ML072040109
| ML072040109 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 07/20/2007 |
| From: | Baty M, Matt Young NRC/OGC |
| To: | Atomic Safety and Licensing Board Panel |
| M A Young, NRC/OGC, 301-415-1523 | |
| References | |
| 50-219-LR, ASLBP 06-844-01-LR, RAS 13901 | |
| Download: ML072040109 (226) | |
Text
July 20, 2007
UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION
BEFORE THE ATOMIC SAFETY AND LICENSING BOARD
In the Matter of )
) AMERGEN ENERGY COMPANY, LLC ) Docket No. 50-219-LR ) (Oyster Creek Nuclear Generating Station) )
NRC STAFF INITIAL STATEMENT OF POSITION ON THE DRYWELL CONTENTION INTRODUCTION Pursuant to 10 C.F.R. §§ 2.1207(a)(1) and 2.337(g)(2), the "Memorandum and Order (Prehearing Conference Call Summary, Case Management Directives, and Final Scheduling Order) (April 17, 2007) (unpublished) ("April 17 Order"), at 4, the Staff of the U.S. Nuclear Regulatory Commission ("Staff") submits its initial written statements of positions and written testimony with supporting affidavits on Citizens' 1 admitted contention. Appended to this filing is the "NRC Staff Testimony of Hansraj G. Ashar, James A. Davis, Mark Hartzman, and Timothy L. O'Hara Concerning Drywell Contention" (July 20, 2007) ("Testimony") and Staff's Exhibits 1 and 2: "SER Excerpts" and "Subsection IWE Excerpts (Parts of -1000, -2000, -3000)." For the reasons set forth below and in the testimony filed herewith, the Staff submits that a careful evaluation of Citizens' Drywell Contention demonstrates that Citizen's challenge to the AmerGen Energy Company, LLC ("AmerGen") application for renewal of the Oyster Creek operating license cannot be sustained.
1 The six organizations are Nuclear Information and Resource Service, Jersey Shore Nuclear Watch, Inc., Grandmothers, Mothers, and More for Energy Safety, New Jersey Public Interest Research Group, New Jersey Sierra Club, and New Jersey Environmental Federation.
BACKGROUND This proceeding concerns AmerGen's application to renew Oyster Creek's operating license for 20 years past the April 9, 2009 expiration date. On November 14, 2005, Citizens filed a timely request for hearing concerning AmerGen's application to renew the Oyster Creek operating license for 20 years past the April 9, 2009 expiration date. On February 27, 2006, the Atomic Safety and Licensing Board ("Board") granted Citizens' intervention petition, admitting a contention that alleged that the license renewal application ("LRA")
2 was deficient due to the failure to include periodic ultrasonic test (UT) measurements of the sand bed region of the drywell liner in the aging management program, and rejecting Citizens' attempt in its reply to expand the contention. LBP-06-07, 63 NRC 188, 211-217 (2006).
3 On February 7, 2006, the Board rejected Citizens' February 7, 2006, attempt to raise contentions challenging, among other things, the adequacy of monitoring of thickness in inaccessible areas of the drywell liner. LBP-06-11, 63 NRC 391, 393-95, review den'd, CLI-06-24, 64 NRC 111 (2006). On June 6, 2006, the Board ruled that Citizens' contention of omission was rendered moot by AmerGen's April 4, 2006, commitment 4 to perform periodic UT measurements in the sand bed region of the drywell (i.e., prior to entering the period of extended operation and every ten years thereafter), but gave Citizens the opportunity to file a new contention challenging AmerGen's new periodic UT program for the sand bed region. LBP-06-16, 63 NRC 737, 742-45 2 Letter from C. N. Swenson, AmerGen, to NRC (July 22, 2005) (ML052080172).
3 The admitted contention alleged that "AmerGen's corrosion management program . . . will not enable AmerGen to determine the amount of corrosion in that region and thereby maintain the safety margins during the term of the extended license." LBP-06-07, 63 NRC at 217. Prior to the admission of the contention, AmerGen committed to "perform a set of onetime thickness measurements . . . in the 'sand bed region' . . . at a sample of areas previously inspected (in the 1990s) and identified as having exhibited corrosion." Letter from C. N. Swenson, AmerGen, to NRC (Dec. 9, 200
- 5) (ML053490219
), at 3.
4 Letter from Michael P. Gallagher, AmerGen, to NRC (Apr. 4, 2006) (ML060970288).
(2006). Citizens' filing was to be limited to AmerGen's new UT program for that region as reflected in its April 4 commitment and was to address the remaining factors in 10 C.F.R. § 2.309(f)(2), as well as the admissibility factors in 10 C.F.R. § 2.309(f)(1).
Id. at 744-45. Citizens subsequently submitted a contention based on the April 4 commitment, got permission to file a supplement limited to AmerGen's UT program as reflected in a June 20, 2006 commitment and new information in that commitment, 5 and filed a supplemental petition.
See [Citizens'] Motion for Leave to Supplement the Petition (June 23, 2006) ("June 23 Petition"); Order (Granting NIRS's Motion for Leave to Submit a Supplement to its Petition (July 5, 2006)
(unpublished); "Supplement to Petition to Add a New Contention" (July 25, 2006) ("Supplement").
6 On October 10, 2006, the Board admitted one of seven challenges 7 raised by Citizens as the following contention: [I]n light of the uncertain corrosive environment and correlative uncertain corrosion rate in the sand bed region of the drywell shell, AmerGen's proposed plan to perform UT tests prior to the period of extended operations, two refueling outages later, and thereafter at an appropriate frequency not to exceed 10-year intervals is insufficient to maintain an adequate safety margin.
LBP-06-22, 64 NRC 229, 255-56 (2006). The Board noted that Citizens' argument was grounded upon the assumption that the corrosion rate in the sand bed region is unknown due to the uncertain corrosive environment.
See 64 NRC at 240. The Board, inter alia, rejected as nontimely Citizens' challenge to the adequacy of monitoring the sand bed region for integrity of 5 Letter from Michael P. Gallagher, AmerGen, to NRC (June 20, 2006) (ML061740573).
6 Appended to Citizens' June 23 Petition and the Supplement are memoranda from Rudolph Hausler, dated June 23 and July 25, 2007, respectively.
7 Citizens challenged as inadequate AmerGen's (1) drywell thickness acceptance criteria, (2) scheduled UT monitoring frequency, (3) moisture and coating integrity monitoring, (4) response to wet conditions and coating failure, (5) scope of UT monitoring to systematically identify and sufficiently test degraded areas, (6) quality assurance for measurements, and (7) methods for analyzing UT results.
See LBP-06-22, 64 NRC at 236.
the epoxy coating and for moisture as well as the challenge to the spatial scope of AmerGen's UT measurements and assertions that monitoring fails to systematically survey thin areas, and the challenge to AmerGen's drywell minimum thickness acceptance criteria (i.e., 0.736 inches and 0.536 inches) used since 1992.
Id. at 244-51, 237-240; reconsideration den'd, Memorandum and Order (Nov. 20, 2006) (unpublished).
On February 9, 2007, the Board denied Citizen's request 8 to admit two late contentions concerning (1) AmerGen's December 3, 2006 proposal 9 to conduct UT monitoring in the embedded region and (2) the inadequacy of AmerGen's proposed monitoring in the sand bed region from the outside. The Board ruled that the contentions were nontimely under 10 C.F.R. § 2.309(f)(2), and inadmissible under § 2.309(f)(1) since they failed to raise a genuine dispute regarding a material issue of law or fact. Memorandum and Order (Denying Citizens' Motion for Leave to Add Contentions and Motion to Add Contention) (unpublished), slip op. at 7, 15-16, 19. In a Memorandum and Order, dated April 10, 2007 (unpublished), the Board also rejected, as unjustifiably late, Citizens' request to add a late contention alleging that UT acceptance criteria for the drywell shell should be increased from 0.536 and 0.736 inches to 0.618 and 0.844 inches, respectively. On March 30, 2007, AmerGen Energy Company, LLC (AmerGen) filed a "Motion for Summary Disposition of Citizens' Drywell Contention" (SD Motion) and attached (1) two 8 Motion for Leave to Add Contentions and Motions to Add Contentions (Dec. 20, 2006). Appended to this filing was the December 3 Supplement (Exh. ANC 1), AmerGen's Advisory Committee on Reactor Safeguards Information Package (Exh. ANC 2), an Oyster Creek shift turnover note for October 21-22, 2006 (Exh. ANC 3), a Memorandum of Dr. Rudolph Hausler (Dec. 19, 2006) (Exh. ANC 4) ("Sixth Hausler Memo"), an Oyster Creek Action Request (Oct. 25, 2006) (Exh. ANC 5), and a Letter from Richard Conte, NRC, to Richard Webster (Nov. 9, 2006) (Exh. ANC 6).
9 Letter from Michael P. Gallagher to NRC (Dec. 3, 2006) (enclosing Post-2006 Refueling Outage Information) ("December 3 Supplement") (ML063390664). Corrections to this letter were submitted on December 15, 2006 (ML063530042).
drawings of the drywell (Exhibits 1 and 2); (2) a Letter from AmerGen to NRC, dated February 15, 2007 (ML070520252), documenting commitments made at a February 1, 2007 Advisory Committee on Reactor Safeguards ("ACRS") meeting, including a commitment to perform full scope of drywell sand bed region inspections every other refueling outage; (3) the Affidavit of Peter Tamburro, dated March 26, 2007 ("Tamburro Affidavit"); (4) the Affidavit of Barry Gordon, dated March 26, 2007 ("Gordon Affidavit"); and (5) the Affidavit of Jon R. Cavallo, dated March 26, 2007 ("Cavallo Affidavit"). The Staff filed a response supporting the motion and Citizens opposed the motion.
See NRC Staff Response to AmerGen's Motion for Summary Disposition (Apr. 26, 2007); Citizens' Answer Opposing AmerGen's Motion for Summary Disposition (Apr. 26, 2007). The Board denied the motion for summary disposition, finding it was unable to conclude as a matter of law that AmerGen's UT monitoring plan is sufficient to ensure adequate safety margins during the period of extended operation. Memorandum and Order (Denying AmerGen's Motion for Summary Disposition) (June 19, 2007) (unpublished), at 12. The Board noted that Citizens had asserted that uncertainty surrounds all of the facts underlying AmerGen's current approach to taking UT measurements once every four years in the sand bed region and that disputes exist regarding (1) the remaining safety margins, (2) the potential for corrosion under the epoxy coating due to defect in and deterioration of the coating that is "past its useful life" and (3) future corrosion rates.
Id. (citing Hausler Memorandum at 1-12). The Board indicated that it viewed the relevant factual issues for litigation as: (1) the amount by which the remaining thickness of the shell exceeds the established criteria in the sand bed region; (2) existence vel non of a corrosive environment, taking into account whether sources of water have been eliminated as well as whether, regardless of the potential existence of water, a corrosive environment can exist in the sand bed region after the sand was removed and the protective coating applied, particularly considering that the sand is no longer there to hold water in the previously corroded areas of the shell; and (3) the corrosion rate - including the uncertainties related to its determination [e.g.,
limited accuracy of the measurement method used, use of a limited number of data points, and the method use to analyze and interpret the data].
SD Order at 7. The Board indicated that evidence on uncertainties may include both the measurement technique and the interpretation of data and that the Board's consideration of uncertainties will determine how much actual values of thickness can reasonably be expected to differ from the measured values.
Id. at n. 10. The Board further indicated that establishment of such facts would determine "how rapidly the thickness is approaching the acceptance criteria and, thus the adequacy of the frequency of UT measurements AmerGen proposed to take during the period of extended operation."
Id. at 7.10 In addition, the Board indicated that Citizens "may not challenge the derivation or validity of the established acceptance criteria or the methodology for analyzing UT results," but are not precluded from arguing that application of these items is inconsistent with past practice.
Id. at 8. The Board also noted that it expected the parties to address whether the "bathtub ring" of corrosion in the sand bed region may lead to a buckling failure between scheduled UT measurements and whether the existing corrosion in sand bed region, if exacerbated by future corrosion, would render "the shell susceptible to buckling failure for which the buckling acceptance criteria [were] developed, and if not, what criteria (such as a leakage criteria) should
apply." Id. at 9 n.11. On July 11, 2007, the Board issued Memorandum and Order Clarifying Memorandum and Order Denying AmerGen's Motion for Summary Disposition (unpublished), in response to a joint motion for clarification filed by the Party on June 29, 2007. Therein the Board stated that 10 The Board indicated that listed factual issues may also require resoluti on of ancillary issues such as whether the monitoring frequency is sufficient to ensure maintenance of an adequate safety margin under the protective epoxy coating in the sand bed region due to "'uncertainty regarding the existence . . . of a corrosive environment in th[at] region and the correlative uncertainty regarding corrosion rates in that region'" as well as the possibility that "'corrosion may occur under epoxy coating in the absence of visual deterioration due to visible . . . pinholes.'" SD Order at 7-8 (citing LBP-06-22, 64 NRC at 240, 242).
"Citizens may not challenge any aspect of AmerGen's UT monitoring program that applies prior to the period of extended operation (i.e. prior to 2009)," but they may use information resulting from Oyster Creek's 2006 UT measurements. Slip op. at 2. The Board clarified that "established" technique for analyzing UT data and calculating the rate of corrosion refers to "the methodology approved by the NRC Staff and relied upon in the Safety Evaluation Report."
Id. The Board admonished Citizens' not to attack AmerGen's "established" technique, but stated that Citizens may seek to demonstrate that AmerGen has not consistently applied its established technique. Id. For the reasons set forth below, the contention lacks merit.
DISCUSSION I. Legal and Regulatory Requirements The scope of license renewal proceedings is limited. The Commission's "[l]icense renewal reviews are not intended to 'duplicate the Commission's ongoing review of operating reactors.'"
Florida Power & Light Co. (Turkey Point Nuclear Generating Plant, Units 3 & 4), CLI-01-17, 54 NRC 3, 7 (2001) (citing Final Rule, "Nuclear Power Plant License Renewal," 56 Fed. Reg. 64,943, 64,946 (Dec. 13, 1991)). Therefore, the license renewal safety review process focuses on the "potential detrimental effects of aging that are not routinely addressed by ongoing regulatory oversight programs."
Id. Consequently, "10 C.F.R. Part 54 requires renewal applicants to demonstrate how their programs will be effective in managing the effects of aging during the period of extended operation."
Id. at 8 (citing 10 C.F.R. § 54.21(a)). Applicants are required to "identify any additional actions, i.e., maintenance, replacement of parts, etc., that will need to be taken to manage adequately the detrimental effects of aging."
Id. (citing Final Rule, "Nuclear Power Plant License Renewal: Revisions," 60 Fed. Reg. 22,461, 22,479 (May 8, 1995)). The Commission has recognized that these "adverse aging effects generally are gradual and thus can be detected by programs that ensure sufficient inspections and testing."
Id. (citing 60 Fed. Reg. at 22,475). License renewal proceedings are limited to a "review of the plant structures and components that will require an aging management review for the period of extended operation and the plant's systems, structures, and components that are subject to an evaluation of time-limited aging analyses."
Duke Energy Corp. (McGuire Nuclear Station, Units 1 and 2; Catawba Nuclear Station, Units 1 and 2), CLI-01-20, 54 NRC 211, 212 (2001) (citing 10 C.F.R. §§ 54.21(a) and (c), 54.4; Nuclear Power Plant License Renewal: Revisions, Final Rule, 60 Fed. Reg. 22,461 (1995)). The issue before the Board in this proceeding is "whether, in light of uncertainty regarding the existence vel non of a corrosive environment in the sand bed region and the correlative uncertainty regarding corrosion rates in that region, Amergen's UT monitoring plan is sufficient to ensure adequate safety margins." SD Order at 2. The adequacy of the Staff's review of AmerGen's application is not at issue.
See Rules of Practice for Domestic Licensing Proceedings-Procedural Changes in the Hearing Process, Final Rule, 54 Fed Reg. 33168, 33171 (Aug. 11, 1989) (citing Pacific Gas and Electric Co. (Diablo Canyon Nuclear Power Plant, Units 1 and 2), ALAB-728, 17 NRC 777, 807, review declined, CLI-83-82, 18 NRC 1309 (1983)). The overall burden is on AmerGen to demonstrate that its UT monitoring program is adequate to manage the aging effects of corrosion on Oyster Creek's drywell so that the intended function of the drywell will be maintained during the period of extended operations.
See 10 C.F.R. § 2.325. Citizens, however, must come forward with evidence that AmerGen's UT program is inadequate. Louisiana Power & Light Co. (Waterford Steam Electric Station, Unit 3), ALAB-732, 17 NRC 1076, 1093 (1983). The Commissions' requirements with respect to the adequacy of Oyster Creek's program to monitor the condition of the drywell during the license renewal period are described in the testimony filed herein. Specifically, as set forth in the Staff's NUREG-1875, "Safety Evaluation Report Related to the License Renewal of Oyster Creek Generating Station" (Mar. 2007, Published Apr. 2007) ("SER"), the applicable legal standard for the Staff's approval of Oyster Creek's program is 10 C.F.R. § 54.21(a)(3), i.e. whether AmerGen has demonstrated "that the effects of aging [of the Oyster Creek drywell shell] will be adequately managed so that the intended function(s) [i.e., structural support and pressure boundary] will be maintained . . . for the period of extended operation.'"
Oyster Creek LBP-06-22, 64 NRC at 241 (quoting 10 C.F.R. § 54.21(a)(3)). One way for a licensee to make the demonstration required by § 54.21(a)(3), is to commit to following the guidance provided by the Generic Aging Lessons Learned ("GALL") Report, NUREG-1801, Rev. 1. AmerGen claimed that its program for managing the effects of aging on the drywell shell is consistent, with an exception and enhancements contained in Commitments 27 and 33, with applicable provisions of GALL.
See SER § 3.0.3.2.23. Therefore, the Staff reviewed Oyster Creek's program to determine consistency with GALL and, in addition, reviewed each exception or enhancement to determine whether it was acceptable and whether the program, as modified, would adequately manage the effect for which it was credited.
See SER at 3-4 to 3-5. II. Staff's Witnesses The attached testimony presents the opinions of a panel of four highly qualified witnesses as follows: 1) Hansraj G. Ashar, a Senior Structural Engineer in the Division of Engineering, Office of Nuclear Reactor Regulation (NRR); 2) Dr. James A. Davis, a Senior Materials Engineer in the NRR Division of License Renewal; 3) Dr. Mark Hartzman, a Senior Mechanical Engineer in the NRR Division of Engineering; and 4) Timothy L. O'Hara, a Reactor Inspector in the Division of Reactor Safety, NRC Region I Office. Testimony at A1(a)-(d). Mr. Ashar (a Structural Engineer) has reviewed plant license and license renewal applications, and has been involved in nuclear power plant standards development.
Id. at A2(a). Mr. Ashar represents the NRC on committees for a number of organizations that develop standards related to nuclear power plant structures, namely, the American Society of Mechanical Engineers (ASME), American Concrete Institute, and American Institute of Steel Construction.
Id. Mr. Ashar was the lead technical coordinator for development of Chapter II of GALL related to the positions on PWR and BWR containments.
Id. Mr. Ashar reviewed Section 4.7.2, "Time Limited Aging Analysis of Drywell Corrosion" in the Oyster Creek License Renewal Application and prepared Section 4.7.2 of the SER.
Id. at A3(a). Mr. Ashar's testimony addresses the Staff's review of AmerGen's program to manage the aging effect of corrosion on Oyster Creek's drywell shell with respect to the Staff's conclusion that AmerGen's drywell monitoring program is sufficient to ensure that the drywell can perform its intended function during the proposed license renewal period.
Id. at A4(a). Dr. Davis (a Metallurgical Engineer) was a member of the license renewal safety audit team for Oyster Creek.
Id. at A3(b). Dr. Davis reviewed portions of Oyster Creek's LRA, including numerous aging management programs.
Id. Dr. Davis has worked on coating and corrosion control since 1968, and has worked on coatings issues at nuclear facilities for the past 16 years at the NRC.
Id. at A2(b). Dr. Davis' testimony addresses Citizens' assertion that visual inspection of the epoxy coating is insufficient because corrosion may occur under the epoxy coating in the absence of visual indications.
Id. at A4(b). Dr. Hartzman (a Mechanical Engineer) is responsible for reviewing safety analyses of ASME Section III Class 1, 2, and 3, and non-ASME piping systems and components submitted by licensees in license amendment requests.
Id. at A2(c). Dr. Hartzman represents the NRC at ASME Section III Code-writing working groups and reviews ASME Section III code cases for NRC endorsement.
Id. In the connection with license renewal, Dr. Hartzman evaluates time limited aging analyses of ASME Section III metal components.
Id. With respect to Oyster Creek's LRA, Dr. Hartzman reviewed the applicability of ASME Section Code Case N-284 to the buckling/stability analyses of the Oyster Creek drywell shell performed by General Electric and the Sandia National Laboratory.
Id. at A3(c).
Dr. Hartzman's testimony addresses the Staff's review of the buckling analysis for the drywell shell and the purpose of the ASME buckling criteria.
Id. at A4(c). Mr. O'Hara (a Reactor Inspector) participated in the License Renewal Aging Management Inspection conducted in March 2006 at Oyster Creek, reviewing Aging Management Programs: B.1.27, ASME Section XI, Subsection IWE Program; and B.1.33, Protective Coating Monitoring and Maintenance Program. Id. at A3(d). Mr. O'Hara participated in the NRC inspection of license renewal commitments regarding the drywell shell and torus conducted during Oyster Creek's 2006 outage. Id. Mr. O'Hara's testimony describes his observations of condition of the drywell in the sand bed region and the Staff's inspection findings concerning AmerGen's commitments related to license renewal and the drywell.
Id. at A4(d).
III. The Concerns Raised by the Contention Lack Merit The Staff's testimony presents its position that the concerns raised by Citizens' contention lack merit because AmerGen's UT monitoring frequency is sufficient to maintain an adequate safety margin in accordance with NRC r equirements. The bases for this position are described in detail in the testimony.
A. Corrosion and UT Measurements Corrosion of the sand bed region of Oyster Creek's drywell shell was identified in the late 1980s, but corrective actions taken, including removal of the sand from the sand bed region and application of a multi-layer epoxy coating in 1992, protect the drywell from additional corrosion.
Testimony at A5. The likelihood of a corrosive environment existing during operation of Oyster Creek is very low because the drywell is inerted during operation.
Id. at A12(a) However, because certain leakages from components inside the drywell can create a corrosive environment during outages, AmerGen committed to monitoring the two trenches for the presence of water until no water is identified for two consecutive outages. Id. Implementation of this commitment will ensure that the embedded portion of the drywell shell is not subjected to corrosion.
Id. As far as eliminating sources of water, AmerGen has committed to monitor the sand bed region drains quarterly during the operating cycle and take corrective actions if water is found.
Id. at A12(b). AmerGen has also committed to using a strippable coating during the proposed period of extended operation that has been shown to be effective in mitigating water intrusion into the annular space between the drywell shell and the shield wall.
Id. The Staff's position is, contrary to Citizens' assertion (see Supplement, July 25, Hauser Memo at 5-6), that corrosion (not visible to an inspector) will not occur in pinholes or holidays in the epoxy coating on the external surface of the drywell.
Id. at A13. First, AmerGen has applied a multi-layer epoxy coating (i.e. one pre-primer, and two top coats) to the exterior of Oyster Creek's drywell shell in the sand bed region.
Id. at A14. The use of multiple layers of epoxy coating results in an extremely low probability that pinholes or holidays will line-up in the three-layer coating.
Id. Second, AmerGen has committed to conducting inspections of the coatings in the sand bed region in accordance with ASME Code Section XI, Subsection IWE (Commitment 27 Items 4 and 21 and Commitment 33).
Id. at A13. Corrosion will be visible because when steel corrodes it produces an oxide film which is higher volume and different in color than the original steel. Id. at A15. This film will be obvious against the gray color epoxy coating, especially to qualified inspectors performing VT-1 inspections in accordance with AMSE Code Section XI, Subsection IWE.
Id. In March 2006, the Staff conducted license renewal inspections at Oyster Creek.
Id. at A16. The NRC inspectors reviewed AmerGen's drywell aging management program (ASME Section XI, Subsection IWE) and found it consistent with guidance for managing the effects of aging on the drywell.
Id. The Staff also reviewed AmerGen's Protective Coating Monitoring and Maintenance Program (i.e. the program for monitoring the coating on the exterior of the drywell) and concluded that the program provided adequate guidance to ensure that effects of aging on the drywell shell, including the sand bed regions, will be adequately managed.
Id. Reactor Inspector Timothy O'Hara inspected the epoxy coatings in Bays 11 and 13 during the 2006 outage.
Id. at A20. He noted that the coating in both Bays was grayish-white in color, appeared to be in excellent condition with no visible evidence of cracking, peeling, or blistering, and that there was no visible moisture.
Id. Mr. O'Hara did not see any sign that corrosion had disturbed the epoxy coating and saw no evidence that corrosion was occurring under the coating.
Id. Mr. O'Hara also reviewed videos of inspections of all the Bays and saw no evidence of moisture, a corrosive environment, or deterioration of the epoxy coating.
Id. On pages 4-59 and 4-60 of the SER, the Staff evaluates the process used by AmerGen related to UT measurements taken after the epoxy coating was applied.
Id. at A22. During the Regional Aging Management inspection in March 2006, the Staff reviewed the historical evolution of the drywell corrosion issue and inquired about Oyster Creek's past UT data and data collection procedures.
Id. at A18. The Staff concluded that Oyster Creek has completed a well-documented baseline inspection on the internal and external drywell condition, which will be reinspected, at appropriate intervals based upon recently-measured corrosion rates, to ensure that the drywell wall thicknesses remain adequate.
Id. During the 2006 outage, Reactor Inspector O'Hara observed the use of a qualified UT procedure, performed by qualified technicians.
Id. at A17. AmerGen was able to obtain comparison readings for 106 of 115 points. Id. AmerGen employed a UT measurement technique (automatic nullification of the epoxy coating thickness) that eliminates an additional measurement step that was required by previous UT measurement techniques.
Id. at A19. This new technique provides more consistent and accurate measurements than the technique used prior to 2006.
Id. at A19. The results of the 2006 UT measurements do not indicate any significant corrosion that would challenge the integrity of the drywell shell.
Id. at A21. Corrosion is not occurring at a rate that warrants UT measurement at an interval shorter than in AmerGen's Commitment 27, Item 21 (i.e., every other outage). Id. at A11. AmerGen has committed to performing a full scope inspection of the drywell sand bed region during inspections prior to the period of extended operation and every other outage thereafter. Id. at A10. Any anomaly associated with inspections during the 2008 outage will tracked prior to the start of license renewal period.
Id. The Staff found the frequency of inspections adequate because UT measurements taken during the 2006 outage confirmed that the epoxy coating in the sand bed area has been effective in reducing the potential for corrosion in this area since the changes in thicknesses were so small.
Id. at A11. B. Acceptance Criteria As stated in the SER, the Staff concluded that AmerGen's aging management program is consistent with GALL AMP XI.S1, AMSE Section XI, Subsection IWE such that the effects of aging will be adequately managed for the period of extended operation provided AmerGen effectively implements enhancements to it aging management program.
Id. at A7. The current licensing basis for Oyster Creek's drywell shell is based on the General Electric (GE) analyses performed in 1991-1992.
Id. The objective of the analyses was to provide reasonable assurance that the structural integrity of the as-built shell would be maintained under refueling conditions, by showing that the stresses do not exceed ASME Section III Subsection NE limits.
Id. The term "buckling" refers to "linear bifurcation buckling," which is the state where adjacent equilibrium configurations of the shell may exist under the same loading condition. Id. at A7. Buckling has been identified as the governing failure mode of the drywell shell in the degraded sand bed region (i.e., the bathtub ring) under refueling load conditions.
Id. The GE analysis included a buckling analysis of Oyster Creek's drywell shell, considering a uniform reduction in the sand bed region wall thickness due to corrosion to 0.736 inches.
Id. The GE analysis also included a buckling analysis that modeled locally thinned areas in the sand bed region. Id. The assumed wall thicknesses in this analysis were 0.536 inches and 0.636 inches, extending over a square foot area tapering to 0.736 inches over a 9 square foot area.
Id. GE's analysis showed that the postulated wall thinning did not have a significant effect on the allowable buckling loads.
Id. Oyster Creek adopted GE's criteria to assess locally thinned areas. Id. Based on information received from the 2006 outage inspection, the Staff concluded that overall changes in the extent of drywell shell corrosion since 1992 are relatively small and are bounded by GE's analyses.
Id. The Staff found that GE's analyses would remain valid for the extended period of operation.
Id. Nevertheless, the Staff did not rely solely on the results of the GE analysis.
Id. at A8. The Staff asked Sandia National Laboratory to perform a confirmatory analysis.
Id. Sandia performed an analysis of the degraded drywell shell using advanced techniques for modeling and analyzing the complex shell structure to determine the controlling loads. Id. Sandia confirmed that Oyster Creek's degraded shell can withstand the postulated load conditions without exceeding ASME Code allowable limits.
Id. Sandia's analysis provides assurance that Oyster Creek's drywell can fulfill its intended functions.
Id. As stated above, Oyster Creek adopted GE's criteria for assessing locally thinned areas. Based upon its review of GPU Nuclear Calculation C-1302-187-5320-024, Rev. 1 (AmerGen Exhibit 17), the Staff concludes that AmerGen has developed three criteria related to acceptance (1) general minimum average required thickness of 0.736 inch, (2) a minimum locally thin thickness of 0.536 inch, in an area of one square foot, with a surrounding one foot transition area to 0.736 inch, and (3) the minimum thickness of 0.49 inch in an isolated area not exceeding an area of a circle having a diameter of two and one-half inches.
Id. at A.9. AmerGen has elected to use a thickness of .636 inched to characterize the extent of degradation below 0.736 inch.
Id. The Staff did not consider Calculation C-1302-187-5320-024, Rev. 2 (March 2007) (AmerGen Exhibit 16) during review of the LRA.
Id. Although the Staff had not conduct a detailed review of Rev 2, Section 6, it appears that Calculation-24, Rev. 2 criterion related to the locally thinned areas is a more stringent criterion, but is encompassed by the criterion of 0.536 discussed in the SER at 4-55 to 4-61.
Id. In sum, contrary to Citizens' assertion, the Staff's position is that the AmerGen Aging Management Program will adequately manage the condition of the drywell shell during the license renewal period.
Id. at A24. Based on the condition of the Oyster Creek drywell shell in the sand bed region during the 2006 outage, the AmerGen Aging Management Program, as enhanced by commitments to perform UT inspections every other outage (as required by proposed license condition), provides reasonable assurance that drywell shell integrity (and the intended function of the drywell) will be maintained during the period of extended operation.
Id.
CONCLUSION For the reasons discussed above, AmerGen's UT monitoring frequency is sufficient to maintain an adequate safety margin in accordance with NRC requirements thus, Citizens' contention lacks merit.
Respectfully submitted, /RA/
Mitzi A. Young Counsel for NRC Staff
/RA/
Mary C. Baty Counsel for NRC Staff
Dated at Rockville, Maryland this 20th day of July, 2007 July 20, 2007 UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD
In the Matter of )
)
AMERGEN ENERGY COMPANY, LLC ) Docket No. 50-219-LR ) (Oyster Creek Nuclear Generating Station) )
NRC STAFF TESTIMONY OF HANSRAJ G. ASHAR, DR. JAMES A. DAVIS, DR. MARK HARTZMAN AND TIMOTHY L. O'HARA CONCERNING DRYWELL CONTENTION Q1. Please state your name, occupation, and by whom you are employed. A1(a). My name is Hansraj G. Ashar ("Ashar").
1 I am employed as a Senior Structural Engineer in the Division of Engineering, Office of Nuclear Reactor Regulation ("NRR"), U.S.
Nuclear Regulatory Commission ("NRC"). A stat ement of my professional qualifications is attached hereto. A1(b). My name is Dr. James A. Davis ("Davis"). I am employed by the NRC as a Senior Materials Engineer in the Office of Nuclear Reactor Regulation ("NRR"), Division of License Renewal. A statement of my professional qualifications is attached hereto. A1(c). My name is Dr. Mark Hartzman ("Hartzman"). I am employed by the NRC as a Senior Mechanical Structural Engineer in the Di vision of Engineering, Office of Nuclear Reactor Regulation ("NRR"). A statement of my pr ofessional qualification is attached hereto. A1(d). My name is Timothy L. O'Hara ("O'Hara"). I am employed by the NRC as a Reactor Inspector in the Division of Reactor Safety, Region I Office. A statement of my 1 In this testimony, the sponsors of each numbered response are identified by their last name; no such designation is provided for paragraphs which are sponsored by all witnesses.
professional qualification is attached hereto. Q2. Please describe your current responsibilities. A2(a). (Ashar) I am responsible for performing safety reviews of nuclear power plant structures including containment structures and various structural supports for the operating nuclear power issues, license renewal applications , and new reactor design certifications. For the last 33 years, I have reviewed plant license and license renewal applications, and have been involved in nuclear power plant standards development. In license renewal activities, I was the lead technical coordinator for development of Chapter II of Generic Aging Lessons Learned (GALL) related to the positions on PWR and BWR containments. I have reviewed the containment section of license renewal applications for PWR and BWR plants. For the BWR containments, I have principally reviewed drywell shells, tori and connecting vents to ensure the integrity of these pressure retaining structural components during the period of extended operation. As part of my duties, I represent the NRC on committees for a number of organizations that develop standards related to nuclear power plant structures, namely, the American Society of Mechanical Engineers (ASME), American Concrete Institute, and American Institute of Steel Construction. A2(b). (Davis) Since November 2005, I have served as an audit team leader and as an audit team member for license renewal audits. Prio r to joining the Division of License Renewal, I was the lead researcher on steam generator issues in the Materials Engineering Branch of the Office Nuclear of Regulatory Research and a technical reviewer in the Materials and Chemical Engineering Branch of NRR, Division of Engineering, responsible for conducting reviews of coating issues, corrosion of metals, service water issues, threaded fasteners, and license renewal. I have worked on coatings and corrosion control since 1968 and have worked on coating issues in nuclear facilities for the past sixteen years at the NRC. I was the NRC representative to ASTM D-33, "Coatings for Power Generation Facilities." This committee prepared standards for testing and inspection of coatings for nuclear power plants. Prior to joining the NRC, I was a member of the NACE Technical Practices Committee on Pipeline Coatings where we wrote standards for the testing and inspection of pipeline coatings including epoxy coatings. These standards included testing to detect pinholes or holidays. I was also a member of the American Water Works Association Technical Advisory Committee on Coatings for Steel Water Pipe and elected Chairman of this committee in 1989. The work of this committee included writing standards for epoxy coated pipe, including requirements for holiday and pinhole testing. A2(c). (Hartzman) I am responsible for reviewing safety analyses of ASME Section III Class 1, 2 and 3 and non-ASME piping systems and components submitted by licensees in license amendment requests. The reviews evaluate licensee-submitted structural integrity analyses of piping systems and components under various Service Level operating conditions, and verifying that the stresses meet the ASME Code Section III or other acceptance criteria for strength and fatigue for each operating service level. I assist regional offices with the evaluation of technical issues arising during inspection activities and, as part of reviews of license renewal applications, evaluate time limited aging analyses of ASME Section III metal components. I represent the NRC at ASME Section III Code-writ ing working groups, such as the WG Vessels and the WG on Methods Development, and I review ASME Section III Code Cases for NRC
endorsement.
A2(d). (O'Hara) As a reactor inspector, I inspect licensee implementation of inservice inspection (ISI) programs. I also participate in license renewal aging management program reviews of licensee ISI activities. In addition, I perform component replacement inspections (steam generators, pressurizers and reactor vessel heads) and general engineering inspections contained in the Reactor Oversight Program. Q3. Please explain your duties in connection with the Staff's review of the License Renewal Application ("LRA") submitted by AmerGen Energy Company, LLC, ("AmerGen" , "Applicant" or "Licensee") for the renewal of the Oyster Creek Facility Operating License No. DPR-16. A3(a). (Ashar) As part of my official duties, I was responsible for the review of the following sections of the LRA: 1) Section 2.4, "Scoping and Screening Results - Structures;" 2) portions of Section 3.5, "Aging Management of Containment, Structures, Component Supports, and Piping and Component Insulation;" 3) Section 4.7.2, "Time Limited Aging Analysis [TLAA] of Drywell Corrosion;" and 4) Section 4.7.3, "TLAA, Equipment Pool and Reactor Cavity Walls Rebar Corrosion." I prepared Section 4.7.2 of NUREG-1875, "Safety Evaluation Report Related to the License Renewal of Oyster Creek Nuclear Generating Station" (March 30, 2007 (published April 2007) ("SER") (ML070890637). Excerpts from the SER are attached hereto as Staff Exhibit 1. The primary objective of my review is to ensure that there is reasonable assurance that the structural integrity and the safety functions of power plant structures, including a containment structure such as the drywell shell, are maintained when subjected to various combinations of the postulated loads including design basis earthquake and accident loads. A3(b). (Davis) As part of my official duties, I was an audit team member for the license renewal safety audit at Oyster Creek. I reviewed the Oyster Creek LRA, including the following aging management programs: B.1.11, "Flow Accelerated Corrosion;" B.1.12, "Bolting Integrity;" B.1.15, "Boraflex Monitoring;" B.1.21, "Above Ground Tanks;" B.1.21A, "Above Ground Tanks-
Forked River Construction Tower;" B.1.25, "Selective Leaching;" B.1.26, "Buried Pipe Inspection;" B.1.26B, "Met. Tower Repeater Engine Fuel Supply - Buried Pipe Inspection;"
B.2.02, "Lube Oil Monitoring Activities;" and B.2.52, "Periodic Inspection," including preparation of Section 3.0.3 of the SER. I also reviewed aging management reviews not consistent with GALL and prepared Sections 3.1.2.3, 3.2.2.3, 3.3.2.3, 3.4.2.3, 3.5.2.3, and 3.6.2.3 of the SER. A3(c). (Hartzman) As part of my official responsibilities, I reviewed the applicability of ASME Section III, Division 1 Code Case N-284-1, "Metal Containment Shell Buckling Design Methods, Class MC," (Code Case N-284-1) to the buckling analyses of the Oyster Creek drywell shell performed by General Electric (GE) and the Sandia National Laboratory (SNL). My expertise is based on my (1) education and experience in the field of Engineering Mechanics, which includes the subject of structural stability theory, (2) experience in reviews of structural and mechanical safety evaluation reports, (3) review of the Code Case for NRC endorsement acceptability, and (4) participation, as the NRC representative, in the ASME Section III Working Group on Vessels, which is responsible for maintaining and updating Code Case N-284-1.
A3(d). (O'Hara) As part of my reactor inspector duties, I participated in the License Renewal Aging Management Inspection conducted in March 2006 at the Oyster Creek Nuclear Generating Station. During this inspection, I reviewed the following Aging Management Programs: B.1.27, ASME,Section XI, Subsection IWE Program; and B.1.33, Protective Coating Monitoring and Maintenance Program. I also participated in the NRC inspection of Amergen's implementation of some license renewal commitments regarding the drywell shell and torus during the Fall 2006 outage at Oyster Creek, and provided information about my inspection activities at Oyster Creek as part of the Staff's presentation at the January 2007 meeting of the Advisory Committee on Reactor Safety ("ACRS"). Q4. What is the purpose of your testimony?
A4. The purpose of this testimony is to present the Staff's position regarding Citizen's contention. As admitted by the Board, LBP-06-22, 64 NRC at 255-56, alleges that:
[I]n light of the uncertain corrosive environment and the correlative uncertain corrosion rate in the sand bed region of the drywell shell, AmerGen's proposed plan to perform UT tests prior to the period of extended operations, two refueling outages later, and thereafter at an appropriate frequency not to exceed 10-year intervals is insufficient to maintain an adequate safety margin.
We have read relevant portions of: the SER; LBP-06-22, 64 NRC 229 (2006); Citizens' "Petition to Add a New Contention" (June 23, 2006) ("June 23 Petition"); Citizens' "Supplement to Petition to Add a New Contention" (July 25, 2006) ("Supplement") and the attached Memorandum from Dr. Rudolf H. Hausler to Richard Webster (July 25, 2006) ("July 25 Hausler Memo"); "AmerGen's Motion for Summary Disposition of Citizens' Drywell Contention" (Mar. 30, 2007);
"Citizens' Answer Opposing AmerGen's Motion for Summary Disposition" (Apr. 26, 2007); "Citizens' Response to NRC" (May 7, 2007); the "Memorandum and Order (Denying AmerGen's Motion for Summary Disposition)" (June 19, 2007) (unpublished); and the "Memorandum and Order (Clarifying Memorandum and Order Denying AmerGen's Motion for Summary Disposition)" (July 11, 2007).
A4(a). (Ashar) My testimony will address the Staff's review of AmerGen's aging management program for the aging effect of corrosion on the drywell shell with respect to the Staff's conclusion that there is reasonable assurance that AmerGen's drywell monitoring plan is sufficient to ensure that the drywell can perform its intended function during the proposed license renewal period. A4(b). (Davis) My testimony will address Citizens' claim that visual inspections of epoxy coating do not reveal that the coating has deteriorated because corrosion may occur under the epoxy coating in the absence of visible deterioration due to nonvisible holidays, or pinholes. A4(c). (Hartzman) My testimony will address, in the context of license renewal, the Staff's review and evaluation of ASME Code Case N-284 as applied to the stability analysis of the drywell shell.
A4(d). (O'Hara) My testimony will provide my observations of the condition of the sand bed region of the drywell shell and the Staff's inspection findings concerning AmerGen's commitments related to license renewal and the drywell. Q5. Describe the corrosion in the sand bed region of the drywell shell at Oyster Creek. A5. Corrosion of the sand bed region of the Oyster Creek drywell shell was identified in the late 1980s. SER at 4-42. The accumulation of water from leaks from the reactor cavity into the gap between the drywell shell and the shield concrete during refueling outages caused corrosion of the exterior of the drywell shell in the sand bed region. Significantly corroded areas in the sand bed region are referred to as the "bathtub" ring of corrosion. Because the high corrosion rate in the sand bed region was attributed to galvanic corrosion of the drywell shell caused by water retained in the sand due to a lack of proper drainage, corrective actions taken included removal of the sand in 1992 and the application of a protective coating to protect the drywell shell from additional corrosion.
See SER at 4-42 to 4-43 (citing AmerGen RAI Response, dated April 7, 2006).
Prior to coating the shell, thickness measurements were taken in each of the 10 bays, from outside the drywell, to establish the minimum general and local thickness of the thinned shell. Id. at 4-43. Measurements from outside the drywell showed a minimum average thickness generally greater than .800 inches (some local areas were less than .800 inches), but the minimum average thickness in these areas was greater than the .736 inches required to satisfy ASME Section III Code requirements for structural integrity of the drywell.
Id. at 4-43. Q6. How was the corrosion of the drywell shell considered in the Staff's review of the Oyster Creek LRA? A6. (Ashar) The Staff reviewed LRA Section 3.5, which contains AmerGen's aging management review results for the drywell, and Section 4.7.2, the TLAA analysis, to determine whether the degraded condition of the drywell shell could withstand the postulated loadings stipulated in the plant's Final Safety Analysis Report (FSAR) without exceeding acceptance criteria. In the description of TLAA 4.7.2, the Applicant states that its ASME Section XI, Subsection IWE aging management program (B.1.27) ensures that drywell shell thickness will not be reduced to less than the minimum required value in any future operation. LRA at 4-55. The Applicant further states that the effects of loss of material on the intended function of the drywell will be adequately managed in accordance with 10 CFR 54.21(c)(1)(iii) for the period of
extended operation.
Id. Due to the extent of reported drywell shell degradation in the sand bed area, the Staff sent requests for additional information (RAIs) about differences in 1994 and 1996 UT results, comparison of such results to UT results in 1992, measurement errors, statistical approach in interpreting the UT results, corrosion rates in the upper spherical and cylindrical areas, and the ability to replicate the locations of UT measurements. In March and April 2006, the Staff was at Oyster Creek, discussed some of these RAIs, and discussed earlier Oyster Creek efforts to mitigate future corrosion. The Staff discu ssed RAIs during a public meeting at NRC Headquarters on June 1, 2006.
NRC inspectors observed UT measurements taken during the 2006 outage and provided updates about AmerGen's drywell activities. The Staff also reviewed AmerGen's statistical analysis of previous measurements in Calculation C-1302-187-5300-11, "Statistical Analysis of Drywell Shell Thi ckness Data Thru 4-24-90" (6/13/90) (see ML06490205) (AmerGen Exhibit 23) and the analysis in Calculation C-1302-187-5320-24, Rev.
0, "OC Drywell Ext. UT Evaluation in Sandbed" (4/16/93) ("Calculation-24")
(AmerGen Exhibit 18), and Calculation-24, Rev. 1 (9/21/06) (AmerGen Exhibit 17). See SER at 59-60.
Q7. What did the Staff conclude about whether the degraded drywell shell can fulfill its intended function during the period of extended operation? A7. (Ashar, Hartzman) As stated in SER, the Staff concluded that AmerGen's aging management program is consistent with GALL AMP XI.S1, ASME Section XI, Subsection IWE such that the effects of aging will be adequately managed for the period of extended operation provided AmerGen effectively implements enhancements to its aging management program.
See SER at 3-143, 4-75.
As part of the containment, the drywell shell is required to provide a pressure retaining function under all the postulated loadings.
See OCNGS FSAR at 3.8-10 to 3.8-19. The current licensing basis for the Oyster Creek is based on analyses performed by General Electric (GE) 1991-92 in GE Reports 9-3, 9-4, "ASME Section VIII Evaluations of the Oyster Creek Drywell for Without Sand Case [Stress and Stability Analyses] - February 1991" (ML0610206140), which are discussed, for example, in the SER at 4-55 to 4-58. The objective of the GE structural analysis of the drywell shell was to provide reasonable assurance that the structural integrity of the as-built shell (i.e., with the degraded wall thickness in the sand bed region) will be maintained under this loading condition, by showing that the stresses do not exceed the ASME Section III Subsection NE stress limits, and that the compressive stress (buckling) requirements of ASME Section III, Code Case N-284 are satisfied. The term "buckling" refers to "linear bifurcation buckling," the state where adjacent equilibrium configurations of the shell may exist under the same loading. This loading is called the "theoretical buckling load," and is determined from a type of structural analysis called "bifurcation buckling" analysis. Local imperfections in thin-walled shells, resulting from the fabrication processes, significantly affect the buckling of fabricated thin-walled shells. Thus, actual buckling of such a shell may occur at a load considerably lower than the theoretical buckling load. Buckling has been identified as the governing failure mode of the drywell shell in the degraded sand bed region under the refueling loading condition. In the refueling condition, the drywell shell is loaded in the vertical direction by gravity and inertia type loads. The minimum uniform degraded sand bed wall thickness necessary to prevent buckling under this loading condition is determined from a buckling analysis of the sand bed region. The criteria in ASME Section III Code Case N-284 are appropriate for determining the stability of the degraded drywell shell.
The GE analysis included a bifurcation buckling analysis of the Oyster Creek drywell shell, considering the uniform reduction in the sand bed region wall thickness due to corrosion to 0.736 inches. The analysis, based on the finite element method, determined that, in this portion of the drywell spherical shell, the axial (meridional) stresses were compressive and the hoop (circumferential) stresses were tensile. This analysis provided the theoretical and allowable buckling stresses for the sand region. In 1992, the Staff's review of that analysis concluded that the Oyster Creek drywell shell analysis was performed in accordance with ASME Code Case N-284 and showed that (1) the load combinations critical to buckling were those involving refueling and post-accident conditions, and (2) application of a factor of safety of 2 and 1.67 for load combinations involving refueling and post-accident conditions, respectively, showed the drywell had adequate margin against buckling with no sand support for an assumed average sand bed region thickness of 0.736 inches.
See Letter from Alexander Dromerick, NRC, to John Barton, GPU Nuclear Corporation, dated April 24, 1992 (enclosing Evaluation Report on Structural Integrity of the Oyster Creek Drywell) (ML070290668) ("1992 SE"), at 4. The Staff found that the procedure used to calculate buckling requirements consistent with ASME Code Case N-284.
See SER at 4-61 to 4-63. GE also performed additional buckling analyses where locally thinned areas in the sand bed region were modeled.
See SER at 3-128. The assumed wall thicknesses in these analyses were 0.536 inches and 0.636 inches, extending over a square foot area and transitioning to a thickness of 0.736 inches over a 9 square foot area. GE used a refined finite element model which took advantage of the symmetry of the modeled degraded area. The analysis showed that the postulated wall thinning did not have a significant effect on the allowable buckling loads. Oyster Creek adopted these results as criteria for assessing local wall thinning in the sand bed region.
See , e.g. Calculation-24, Rev.1 (AmerGen Exhibit 17) at 10 of 117. See also SER at 4-56 to 4-58. Based on information received from the 2006 outage inspection, the Staff concluded that overall changes in the extent of drywell shell corrosion since 1992 were relatively small and were bounded by the analysis and calculations done by GE.
See SER at 3-137 to 3-143, 4-72 to 4-73. Therefore, the Staff concluded that the degraded drywell will be able to perform its intended function and the effects of aging will be adequately managed during the extended period of operation, provided AmerGen implements commitments to its aging management program.
See, id at 3-422 to 3-424, 4-73 to 4-75. Q8. Did the Staff rely solely on the results of the 1992 GE analysis? A8. (Ashar, Hartzman) No.
In order to provide additional assurance that the aging management program would ensure that the drywell shell could perform during the renewal period, the Staff asked Sandia National Laboratories (Sandia) to perform an analysis of the degraded drywell shell based on advanced techniques for modeling and analyzing the complex shell structure and to determine controlling postulated load conditions. See SER at 4-71.
Sandia developed a full (360 º) three dimensional (3D) finite element model of the Oyster Creek drywell shell that permitted a more sophisticated analysis of structural details that accounted for asymmetries of drywell shell. Sandia used the degraded shell thicknesses in the Applicant's Calculation-24, Rev. 0 (AmerGen Exhibit 18) and performed analyses for both the undegraded and degraded shell. For the degraded shell, the load condition with a minimum margin against the ASME allowable limits was found to be the refueling condition. For this loading condition, the safety factor against buckling was found to be 3.85 for the undegraded shell and 2.15 for the degraded shell. For the operational load condition, such as the refueling condition, the ASME Code requires a minimum safety factor of 2.00. Thus, the Sandia analysis confirmed that the Oyster Creek degraded drywell shell could withstand the postulated load conditions without exceeding the ASME Code,Section III, Subsection NE. See SER at 4-72. This confirmation provides assurance that the Oyster Creek drywell shell can fulfill its intended function of providing the pressure retaining barrier against uncontrolled release of radioactivity under all postulated load conditions, provided the drywell shell does not experience significant additional degradation. Q9. You testified that the Sandia analysis used information from the 1993 version of Calculation-24. Did the Staff consider information in later versions of that calculation during its review of AmerGen's LRA? A9. (Ashar) Yes. The Staff was aware of Calculation-24, Revision 1 (AmerGen Exhibit 17), which had used the same 1992 bathtub area measurements that are in Rev.0. In Calculation-024, Rev. 0 (AmerGen Exhibit 18), there are eight raw 1992 UT data points in Bay 1, that are between 0.636 inch and 0.736 inch, and no UT data point is less than 0.636 inches. In Bay #13, there are nine raw data points between the thickness of 0.636 inch and 0.736 inch, and one data point (i.e., 0.618 inch) below 0.636 inch, but above 0.536 inch. AmerGen has adjusted the raw data points less than 0.736 inch to account for surface roughness for their use in its structural evaluation.
Id. at 67-87 of 117.
Based on a review of the Calculation-24, Revs. 0 and 1 (AmerGen Exhibits 18 and 17) analysis of degraded areas, and AmerGen responses to Staff RAIs (see SER section 4.7.2), AmerGen has three criteria related to acceptance of the shell thicknesses: 1) a general minimum average required thickness of 0.736 inch; (2) a minimum locally thin thickness of 0.536 inch, in an area of one square foot, with a surrounding one foot transition area to 0.736 inch; and (3) the minimum thickness of 0.49 inch in an isolated area not exceeding an area of a circle having a diameter of two and one-half inches.
E.g., Calculation-24, Rev. 1 (AmerGen Exhibit 17) at 10-11 of 117. In addition, AmerGen has elected to use a thickness of 0.636 inch to characterize the extent of degradation below 0.736 inch. See id. The Staff did not consider Calculation C-1302-187-5320-024, Rev 2 (Mar. 2007) (AmerGen Exhibit 16) during the review of t he LRA because that document was not submitted to the NRC for review in connection with the LRA (or available before issuance of the SER).
Although the Staff has not conducted a detailed technical review of Calculation-24, Rev. 2, Section 6.0 (at 10-15 of 183) of the calculation indicates that AmerGen analyzed 2006 UT results from the drywell exterior using a local acceptance criterion different from a previous version of the calculation. Section 6.1 of Calculation-24, Rev. 2, indicates a general uniform wall thickness criterion of 0.736 inch and methods for implementing the criterion under various UT measurements, but a local wall thickness criterion for buckling as an average of 0.636 inch in an area no larger than 12 inches by 12 inches square. See AmerGen Exhibit 16 at 10-15 of 183. The criterion allows the transition (from 0.636 inch to 0.736 inch) thickness in the area no larger than 36 inches by 36 inches square.
Id. However, Revision 2 refers to the same analysis that was used in Calculation-24 , Revisions 0 and 1. The very local wall thickness criterion of 0.49 in an area not exceeding a 21/2 inch diameter circle has not changed. Thus, it appears that the Calculation -24, Revision 2 criterion for locally thin areas (i.e., 0.636 inch) is a more stringent criterion, and is encompassed by the Staff's review based on a very local criterion of 0.536 inch discussed at SER pages 4-55 to 4-60. Q10. How often will UT measurements of the sand bed region of the drywell be taken under AmerGen's aging management program? A10. (Ashar) In LRA, section B.1.27, "ASME Section XI, Subsection IWE,"
AmerGen indicates that inspection of the drywell shell and other primary containment components is in accordance with this aging management program.
LRA at B-75. Commitment 27, Item 21, indicates that, during the period of extended operation AmerGen will perform the full scope of drywell sand bed region inspections prior to the period of extended operation and then every other refueling outage thereafter. The full scope inspection is defined as:
- UT measurements from inside the drywell
- Visual inspections of the drywell external shell epoxy coating in all ten bays
- Inspection of the seal at the junction between the sand bed region concrete and the embedded drywell shell
- UT measurements at the external areas inspected in 2006. The Staff found AmerGen's Commitment 27 items acceptable.
See SER at 4-75. As noted in the SER (at 1-18), the Staff plans to include a license condition that requires the applicant to perform full scope inspections of the drywell sand bed region every other refueling outage during the proposed renewal period. Q11. Why did the Staff find the monitoring frequency adequate?
A11. (Ashar, Davis) UT measurements taken during the October 2006 outage confirmed that the epoxy coating in the sand bed area has been effective in reducing the potential for corrosion in this area since the change in thicknesses were small. In its letter of December 3, 2006 (ML063390664) (AmerGen Exhibit 12), AmerGen indicated that wall thinning of 0.038 inch had taken place in trenches 5 and 17, since 1986, when the trenches were constructed.
See SER at 3-423 to 4-424. These trenches are in the inside of the drywell and do not have an epoxy coating to prevent corrosion. This corrosion identified in the trenches is equivalent to about 2 mils per year of corrosion in the specific areas of the trenches. The Staff reasoned that, if this corrosion rate is applied to the lowest average thickness of 0.8 inch for four years, the average thickness would be reduced to 0.792 inch, and hence, higher than the average minimum required thickness of 0.736 inch. This approach is conservative because it involves the application of a very local thickness reduction to the entire sand bed region and, because the rate of future corrosion normally decreases over time due to the formation of corrosion products.
In addition, AmerGen has committed (Commitment 27, Items 16, 20 and 21) to perform inspections during the 2008 outage, which will include UT examinations in the trench areas, as well as in the rest of the sand bed area.
See SER at 4-74 to 4-75. Any anomaly associated with these measurements will be tracked prior to the start of the extended period of operation. In summary, the Staff's view is that no significant corrosion is occurring in the sand bed area at a rate that would warrant the UT measurement at an interval shorter than in Commitment 27, Item 21 (i.e., every other outage). Q12. Can a corrosive environment exist in the sand bed region after removal of the sand and application of the epoxy coating?
A12(a). (Ashar) Because the drywell is inerted during operation, the likelihood of corrosive environment existing inside the drywell during operation of the plant is very low.
However, certain leakages from components inside the drywell can create a corrosive environment during outages, as found in the trenches during the October 2006 inspections. In Commitment 27, Item 20 (see SER at A-31 to A-32), AmerGen committed to monitor the two trenches for the presence of water. Visual and UT inspections of the shell within the trenches will continue to be performed until no water is identified in the trenches for two consecutive refueling outages, at which time the trenches will be restored to their original design (e.g., refilled with concrete) to minimize the risk of future corrosion.
Proper implementation of this commitment will ensure that the embedded portion of the inside of the drywell shell will not be subjected to corrosion. Routine implementation of IWE program (LRA AMP B.1.27) will ensure that the junction between the bottom concrete floor and the drywell shell is monitored during each inspection period. A12(b). (Davis) As far as eliminating sources of water, Oyster Creek has committed (Commitment 27, Item 3) to monitor the sand bed region drains quarterly during the operating cycle. If water is detected, the following actions will be taken: 1) The leakage rate will be quantified for flow rate and trended; 2) The source of water will be investigated and diverted, if possible, from entering the sand bed region; 3) The water will be analyzed to determine the source of leakage; 4) If a leak is detected, the coating and moisture barrier will be inspected in any bays affected by the leakage during the next refueling outage or outage of opportunity; 5) If the coating is degraded, and visual inspection indicates corrosion has taken place, then UT measurements will be taken in the affected areas of the sand bed region from either the inside or outside of the drywell to ensure that the shell thickness in areas affected by water leakage is measured; 6) UT measurements will be taken in the upper region of the drywell consistent with the existing program; and 7) Any degraded coating or seal will be repaired in accordance with station procedures.
See SER at 1-17. Oyster Creek has also committed (Commitment 27, Item 2) to use a strippable coating during the period of extended operation that has been shown to be effective in mitigating water intrusion into the annular space between drywell shell and shield wall. This has been applied to the refueling cavity liner during periods when the refueling cavity is flooded. This commitment applies to refueling outages prior to and during the period of extended operation.
See SER at 3-115.
Q13. Citizens contend that corrosion (not visible to an inspector) can occur in pinholes or holidays in the epoxy coating on the external surface of the drywell. Do you agree? A13. (Davis) In my opinion, Citizens' contention lacks technical merit because AmerGen has committed to conduct inspections of the coatings in the sand bed region in accordance with the ASME Code Section XI, Subsection IWE.
See Commitment 27, Items 4 and 21 and Commitment 33 in SER, Appendix A. During the audit at Oyster Creek, the Applicant stated that visual inspection of the containment drywell shell, conducted in accordance with ASME Section XI, Subsection IWE, is credited for aging management of accessible areas of the containment drywell shell. Typically this inspection is for internal surfaces of the drywell. The exterior surfaces of the drywell shell in the sand bed region for Mark I containment are considered inaccessible by ASME Code Section XI, Subsection IWE; thus, visual inspection was not possible for a typical Mark I containment before the sand was removed from the sand bed region in 1992. After removal of the sand, an epoxy coating was applied to the exterior wall in the sand bed region.
See SER at 3-118 to -119. Excerpts from Subsection IWE are attached as Staff Exhibit 2. Q14. What is the potential for corrosion under epoxy coating due to defects in and deterioration of the coating? A14. (Davis) There is a multi-layer epoxy coating on the exterior of the Oyster Creek drywell shell in the sand bed region to prevent corrosion in that region. This coating was discussed in detail under SER Open Item 4.7.2-3, which has been closed. This coating was applied as part of corrective actions taken in the late 1980s and early 1990s to prevent additional corrosion of the drywell shell in the sand bed region. This coating was discussed in detail under Open Item 4.7.2-3 in the SER. In addition to removing the sand from the sand bed region, a coating was applied to the exterior of the drywell shell in the sand bed region with a multi-layered epoxy system (i.e., one pre-primer coat, and two top coats) to prevent any water or moisture that might reach the sand bed region from contacting the exterior shell. See SER at 1-15 to 1-18, 3-163 to 3-167, 4-67 to 4-70.
Thus, the use of multiple layers of epoxy coatings at Oyster Creek results in an extremely low probability that pinholes and holidays will line up in the three layer coating system. In addition, pinholes usually develop during the initial cure of the coating and new pinholes would not likely develop over time in the absence of conditions such as mechanical impacts or exposure to ultraviolet light.
Q15. What is the basis for your conclusion that corrosion would be visible? A15. (Davis) When a steel surface corrodes, the oxide film that is generated has a higher volume than the original volume of the steel because iron in the steel is converted to iron oxide that is then hydrated, which leads to blistering and other observable anomalies in the coating. The film will be rust colored and will be obvious against the gray colored epoxy coating. AmerGen's protective coating monitoring and maintenance program specifies VT-1 visual inspections of epoxy coating using qualified inspectors. The rust colored corrosion product will be easily detected during VT-1 inspections of the coating on the external surface of the drywell shell in accordance with the ASME Code,Section XI, Subsection IWE. Additional guidance for inspection of the epoxy coatings on the drywell shell are in GALL section XI.S1, "ASME Section XI, Subsection IWE," and XI.S8, "Protective Coating Monitoring and Maintenance Program." These sections indicate that inspectors are to be trained to inspect the surfaces within the scope of IWE for evidence of flaking, blistering, peeling, discoloration, and other signs of degradation. AmerGen has committed to follow this guidance (Commitment 27, Items 4 and 21 and Commitment 33 in the SER Appendix A).
The Applicant further stated that the existing Protective Coating Monitoring and Maintenance Program does not invoke all of the requirements of ASME Code Section XI, Subsection IWE. AmerGen has committed (Commitment 27, Item 4) to enhance the program to incorporate coated surfaces inspection requirements specified in ASME Code Section XI, Subsection IWE and has provided specific enhancements that will be made to the program as follows: Sand bed region external coating inspections will be per Examination Category E-C (augmented examination) and will require VT-1 visual examinations per IWE-3412.1.
- a. The inspected area shall be examined (as a minimum) for evidence of flaking, blistering, peeling, discoloration, and other signs of distress.
- b. Areas that are suspect shall be dispositioned by engineering evaluation or corrected by repair or replacement in accordance
with IWE-3122.
- c. Supplemental examinations in accordance with IWE-3200 shall be performed when specified as a result of engineering
evaluation.
SER at 3-120. If the coating is damaged and corrosion is observed, AmerGen will conduct UT measurements of that area and will evaluate the results following the existing program. SER at A-18 to A-20 (Commitment 27, Item 1). The Applicant committed to conduct additional visual inspections of the epoxy coatings applied to the external surface of the drywell shell in the sand bed region prior to entering the period of extended operation. SER at A-22 to A-23 (Commitment 27, Item 4). AmerGen has committed (Commitment 27, Items 4 and 21, and Commitment 33) to enhance the Inservice Inspection Program to require 100% inspection of the epoxy coatings every other refueling outage during the period of extended operation.
The Staff, as noted in SER Sections 3.0.3.2.23 and 3.0.3.2.27, concluded that the performance of ASME Section XI, Subsection IWE, visual inspections of the drywell in all ten bays of the sand bed region every other refuelling outage, and AmerGen taking appropriate actions when significant corrosion is detected, provides assurance that effects of aging will be adequately managed so that intended functions will be maintained throughout the renewal
period. It should also be noted that, Regulatory Guide 1.54, Rev. 1, "Service Level I, II, and III Protective Coatings Applied to Nuclear Power Plants," which refers to ASTM D 5163, "Standard Guide for Establishing Procedures to Monitor the Performance of Safety Related Coatings in an Operating Nuclear Power Plant," and ASME Code Section XI, Subsection IWE, "Requirements for Class MC and Metallic Liners of Class CC Components of Light Water Cooled Plants," recommend visual inspection of coatings for evidence of degradation before conducting additional tests. Q16. What did the NRC learn during license renewal inspections at Oyster Creek? A16. (O' Hara) As an inspector, I reviewed the implementation of AmerGen's B.1.27, ASME Section XI, Subsection IWE Program, during the March 2006 inspection and found that AmerGen's program was consistent with guidance for managing aging effects of the drywell. This decision was reached after interviews with cognizant engineering and management personnel from AmerGen, review of historical data on the drywell corrosion issue, review of the licensee's evaluation and analysis of the historical drywell testing data, and the licensee's commitment to significantly improve the rigor with which they had been addressing the condition of the drywell and their program to monitor the aging effects of the drywell. See NRC Inspection Report 05000219/2006007 (9/21/06) (ML062650059), at 16. The Staff also concluded, regarding B.1.33, Protective Coating Monitoring and Maintenance Program, that the licensee's program provided adequate guidance to ensure that aging effects of the drywell shell will be adequately managed.
Id. at 16-17. This program is used to monitor the coating on the exterior of the drywell. Q17. Did NRC inspectors observe UT measurements of the drywell shell during the Fall 2006 outage? A17. (O'Hara) Yes. During the fall 2006 inspection, I observed the use of a qualified UT procedure, performed by qualified technicians. Exelon Procedure TQ-AA-122, Revision 3; "Qualification and Certification of Nondestructive (NDE) Personnel" provides the standard used by AmerGen to qualify and certify NDE technicians. In general, UT personnel are qualified in accordance with ASNT SNT-TC-1A, through 1984 edition; ANSI/ASNT CP-189, 1991 and 1995 editions; and ASME Section XI, 1986 Edition through 2001 Edition, 2003 Addenda, as applicable. For UT, personnel certification Attachment 5 of TQ-AA-122 provides the detailed qualification which must be demonstrated to perform examinations for the requirements of ASME Section XI. All the aforementioned standards have been previously reviewed and accepted by the NRC for the specified qualification processes. The calibrations and data collection activities were performed per the procedure, recorded on appropriate data sheets, and the results were reviewed and approved by a qualified, Level III Nondestructive Evaluation Examiner. Then all data was evaluated and analyzed by qualified, experienced engineers to determine whether acceptance criteria were met. Upon confirming that all recorded data met the wall thickness criteria, the Licensee determined that the GE Analysis report of record was validated for the wall thickness data recorded. Based upon the calculated corrosion rate (2006) and the remaining wall thickness, the Licensee demonstrated that the drywell wall thickness will be maintained above minimum requirements until the next refueling outage in 2008. The UT and visual (VT) records from this inspection in the fall of 2006, were well documented, the data was correctly collected, personnel were knowledgeable and qualified to perform the required inspections. The NDE level III supervising the data collection was knowledgeable and provided accurate direction to the data collection personnel. All data collected was reviewed for acceptability before it was given to engineering. Upon receiving the validated data, engineering personnel conducted appropriate and accurate analyses and evaluations based upon written procedures and criteria. Upon completion of the evaluations, appropriate engineering and station management reviews were conducted.
The external UT wall thickness measurements taken during 2006 showed no significant corrosion compared to1992 measurements. It should be noted that the Licensee had intended to re-measure approximately 115 external points which had been prepared and measured in 1992, prior to application of the epoxy coating. Due to the difficulty in finding and matching up all of these points, the licensee was able to obtain 2006 comparison readings for approximately 106 points of the planned 115. For the exter nal points measurements I observed during the inspection, AmerGen found it difficult to locate and identify some of the points. For example, some measurements had not been ground as deeply as others and some had not been referenced correctly. This indicates that it may not always be appropriate to compare 2006 point readings with external readings from previous years. During my observations of the internal drywell UT measurements, there was a very light surface coating of oxidation present on small uncoated portions of the drywell shell in the trenches in Bay 5 and 17, however, no wall thickness loss (i.e., flaking) was apparent. The licensee had coated the internal drywell test locations with grease after prior UT measurements in 1994 to prevent this oxidation, but had apparently not coated these areas or the grease was disturbed during preparation for the 2006 inspection. The presence of the water in the trenches in Bay 5 and Bay 17 was the only evidence of a corrosive environment inside the drywell. The Licensee monitors the inside of the drywell under their ASME Section XI, Subsection IWE program, and I verified that the interior of the drywell is inspected and actions taken when coating deterioration is detected. And, in addition, the internal sections of the drywell are measured with UT for wall thickness in the area of the sand bed. The water in the trenches was determined to not be a corrosive environment because the water had reacted with the concrete and had become a non-corrosive (i.e., basic) environment. Q18. How were the UT measurements taken during the 2006 outage? A18. (O'Hara) During the 2006 outage measurements, the licensee employed a UT measurement technique (automatic nullification of the epoxy coating thickness) that eliminated an additional measurement step which had been used in previous measurements prior to 2006. Prior to 2006 the licensee had measured the epoxy coating thickness and then manually subtracted the thickness from the recorded thickness of the coating and shell measured together. The new technique, known as wave skip or half-wave technique, involved calibration of the UT instrument to record the first signal reflection of the coating-to-metal interface and deduction of that distance from the overall coating and metal thickness measurement, thus effectively cancelling out the coating thickness and reporting only the remaining metal thickness. This technique had not been used during previous inspections of the drywell thickness after the epoxy coating had been applied in 1992. In my opinion, this technique provided more consistent and accurate measurements than pre-2006 measurements. During the Regional Aging Management inspection, in March 2006, I was assigned to review the ASME,Section XI, Subsection IWE Program and the Protective Coating Monitoring and Maintenance Program. In reviewing the historical evolution of the drywell corrosion issue, I inquired about the licensee's past data and data collection procedures. Discussions with AmerGen regarding how past data could be directly compared to the 2006 data, in part, led to AmerGen commitments that were verified and results reported in NRC Inspection Report 05000219/2006013 (1/17/07) (ML070170396). Basically, the Licensee has completed a well-documented baseline inspection on the internal and external drywell condition which will be reinspected, at appropriate intervals based upon recently-measured corrosion rates, to ensure that the drywell wall thickness remains adequate to perform its safety function. Q19. What is your opinion regarding AmerGen's UT measurement uncertainties during the 2006 outage?
A19. (O'Hara) From my observation of the UT equipment calibration, observation of the data collection and the Level III review of t he reported data, the measurement uncertainty on these measurements was very low. The use of UT technology as a thickness gauging tool is a very elementary application of the technology and has been shown to be very accurate in many industrial applications. In addition, it is my opinion that the elimination of an additional measurement step to account for the epoxy coating thickness simplified the measurement of the actual remaining metal thickness and enabled meas urement with greater accuracy. Also, my experience has been that there would be significant variability in thickness for a manually applied coating applied in the confined space of the external drywell bays. The licensee's use of a technique that accounts for the thickness of the epoxy at each reading location removed a significant potential measurement error. Thus, in my opinion, the 2006 data should be considered to be more accurate than the licensee's previous UT metal thickness measurements. It is also my opinion, based upon discussions with several licensee personnel about the methods used to remove the sand and scale from the exterior of the drywell and the methods used to prepare the metal surface prior to applying the epoxy coating in 1992, that the licensee has included some additional conservatism in the external UT thickness measurements by not taking credit for metal that was intentionally removed in 1992 prior to applying the epoxy coating. In order to provide a smooth surface for UT readings in 1992, the licensee prepared the dimpled surface of the external locations to be measured by grinding smooth, flat surfaces on the outside of the drywell. During this preparation process, the licensee did not control the amount of material removed. Thus, readings taken since the application of the epoxy coating can be expected to be thinner than the original, 1992 actual thickness by some amount not attributable to corrosion, but attributable to the surface prep process. This added conservatism would affect measurements taken since the application of the epoxy coating, however, because the licensee cannot quantify the amount of this conservatism, no credit has been taken by the licensee in its analysis of the drywell condition. The licensee also has some limited video and pictorial records on the processes followed during the 1992 effort to remove the sand and to clean the drywell and apply the epoxy coating, which I viewed. Q20. What did you observe regarding the condition of the epoxy coating on the exterior of the drywell shell in the sand bed region? A20. (O'Hara). During the fall 2006 outage, I inspected (by physically entering the Bays 11 and 13) the external epoxy coating on the outside of the drywell. The coating in both bays was grayish-white in color and appeared to be in excellent condition with no visible evidence of cracking, peeling or blistering. The general condition of each bay was good with no moisture visible. I could not see any sign that corrosion had disturbed the epoxy coating and saw no evidence that corrosion was occurring under the epoxy coating. In addition to entering Bays 11 and 13, I also viewed video tapes of all Bays and reviewed the VT data sheets from all Bays. The video tapes showed the same general condition in all bays and showed that the epoxy coating had not been visibly disturbed since the original application. The epoxy coating, in all Bays, appeared to be in good condition and undisturbed since the application of the epoxy in 1992.
Regarding the potential for a corrosive environment to exist on the outside of the drywell, my visual observations of (and a review of records concerning) the exterior of the drywell and the epoxy coating condition did not reveal any evidence of moisture on the drywell exterior or the coating in the sand bed region. Additionally, my reviews did not identify any evidence that a corrosive environment had been recently active on the drywell exterior or the epoxy coating in the sand bed region. Q21. What do the 2006 UT results show about whether remaining thicknesses of the shell exceeds AmerGen's UT acceptance criteria?
A21. (Ashar)
A review of the 106 UT thickness measurements in the locally thinned areas made during the October 2006 outage, in general, indicated that the metal thicknesses in these areas were lower than those in 1992.
See AmerGen Letter to NRC (Dec. 3, 2006) (AmerGen Exhibit 12). AmerGen attributed the lower metal thickness as largely due to using a more accurate UT instrument and the procedure used to take the measurements, which involved moving the instrument within the locally thinned areas to locate the minimum thickness in the area (SER at 3-138). However, a review of the data attached to AmerGen's December 3 letter (see SER at 3-424) indicated that the measurements did not exceed the acceptance criteria for the locally thinned areas. Thus, the results of the 2006 UT measurements do not indicate any significant corrosion that would challenge the integrity of the drywell shell.
See SER at 3-142 to 3-143. Q22. What is the corrosion rate in the sand bed region, including uncertainties related to its determination?
A22. (Ashar)
AmerGen has asserted, based on the comparison of the UT measurements in October 2006, and earlier UT measurement data, that the drywell corrosion in the sand bed area has been arrested.
See, e.g., SER at 3-126. AmerGen, however, has described ten sources of uncertainties associated with UT measurements of the drywell shell (e.g. UT instrumentation, drywell surface roughness, probe location repeatability, UT probe rotation, temperature effects, NDE technician, UT unit setting, etc.) and its plans to address each source of uncertainty through implementation of proper procedures and training.
See SER at 4-53 to 4-55.
Between 1986 and 1992, the wall thickness loss at the thinnest located was reported to be 70 mils, resulting in linear corrosion rate of 12 mils/year. SER at 4-43.
As indicated on SER pages 4-59 and 4-60, the Staff evaluated the process used by AmerGen related to the UT measurements taken after the epoxy coating was applied. Initial locations identified in 1986 and 1987 where corrosion loss was most severe were selected for repeat inspection over time to measure corrosion rates. For locations where the initial investigations found significant wall thinning, new wall thickness were measured by UT at 49 points in 6" x 6" area, and verified for compliance with the minimum required wall thickness criteria. A statistical analysis was then performed of this dataset, and the mean value was compared to the previously calculated mean values at this location. A linear regression analysis of the old and new values was then performed to determine the slope and 95% upper and lower confidence intervals. For a non-zero slope, the slope of the line represents the corrosion rate at this location. The lower 95% confidence interval was then projected into the future and compared with the required minimum wall thickness criteria.
The use of the lower 95% confidence interval in projecting the future thicknesses, and the requirement that the thickness acceptance criteria are met, is consistent with the ASME Subsection IWE requirements for evaluating the UT results. The Staff concluded that the use of this process is acceptable for assessing the future corrosion rate.
See SER at 4-60.
As previously noted, October 2006 outage results confirmed that the epoxy coating in the sand bed area has been effective in reducing corrosion in this area and indicated a corrosion rate of about 2 mils per year based on the wall thinning in the trenches.
See SER at 3-424. When this corrosion rate is applied to the lowest average thickness of 0.8 inch for four years, the average thickness would reduce to 0.792 inch, which would be higher than the average minimum required thickness of 0.736 inch.
Q23. What is the Staff's position regarding the necessity for UT monitoring of the Oyster Creek drywell shell when visual inspection results for the epoxy coating do not identify any evidence of deterioration of the epoxy coating?
A23. The Staff position is that UT monitoring in the sand bed region is necessary even when visual inspection results for the epoxy coating satisfy the acceptance criteria of ASME Section XI, Subsection IWE-3512 due to (1) the inability to make a definitive assessment regarding the uncertainties related to corroded areas, (2) only three reliable points of metal thickness data, and (3) the unknown duration of the effectiveness of the epoxy coating in protecting the sand bed region metal surfaces. Thus, both the VT-1 examination of the epoxy coating and UT monitoring should continue throughout the extended period of operation as committed by AmerGen in Commitment 27, Item 21. Q24. What is the Staff's conclusion regarding whether the aging management program for the drywell shell is adequate for the license renewal period?
A24. The results of the 2006 outage inspection indicate that AmerGen corrective actions (removal of the sand and application of epoxy coating) have been effective in managing corrosion of the drywell shell. AmerGen's Aging Management Program includes commitments listed in Appendix A of the SER to periodically monitor corrosion in the sand bed region of the drywell shell, identify the extent of additional degradation, perform additional UT measurements and compare thickness differentials, report stat istically significant corrosion to the NRC, and perform an operability determination and justification for operation until the next inspection. Based on the condition of the Oyster Creek drywell shell in the sand bed region during the 2006 outage, the AmerGen Aging Management Program, as enhanced by commitments to perform UT inspections every other outage (as required by proposed license condition), provides reasonable assurance that drywell shell integrity (and the intended function of the drywell) will be maintained during the period of extended operation. Thus, AmerGen's Aging Management Program will adequately manage the condition of the drywell shell during the
proposed license renewal period.
Hansraj G. Ashar Statement of Professional Qualifications
CURRENT POSITION:
Senior Structural Engineer Division of Engineering, Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Rockville, MD EDUCATION Bachelor of Civil Engineering, Gujarat University, India Masters Degree in Civil-Structural Engineering, 1958, University of Michigan, Ann Arbor, MI
Registered Professional Engineer in the States of Ohio and Maryland.
EXPERIENCE For the last 33 years, I have been working as a Structural engineer/Sr. Structural Engineer with the U.S. Nuclear Regulatory Commission in review of the plant licenses, standards development, containment related research activities and license renewal activities. For the first eleven years of my career, I have worked as a Bridge Engineer in the States of Ohio, New Jersey; and in Wiesbaden Germany on designing steel, reinforced and prestressed concrete bridges. The next five years, I worked as a Lead Civil Engineer on developing design documents and procurement specifications for nuclear power plants, namely, Three Mile Island, Unit 2, Forked River, and Oyster Creek.
I represent NRC in a number of Standards Developing Organizations, namely, American Society of Mechanical Engineers (ASME), American Concrete Institute, and American Institute of Steel Construction on several committees developing standards related to the nuclear power plant structures. I am a fellow member of the American Concrete Institute, and the American
Society of Civil Engineers.
REGULATORY DOCUMENTS (Principal Author):
Information Notices
IN 93-53 Effects of Hurricane Andrew on Turkey Point Nuclear Generating Station and Lessons Learned, April 1994
IN 95-49 Seismic Adequacy of Thermo-Lag Panels, October 1995 Supplement 1: Seismic Adequacy of Thermo-Lag Panels, December 1997
IN 97-10 Liner Plate Corrosion in Concrete Containments, March 1997 IN 97-11 Cement Erosion from Containment Subfoundation at Nuclear Power Plants, March 1997
IN 97-22 Failure of Welded Steel Moment-Resisting Frames During the Northridge Earthquake, April 1997
IN 97-29 Containment Inspection Rule, May 1997
IN 98-26 Settlement Monitoring and Inspection of Plant Structures Affected by Degradation of Porous Concrete Subfoundation, July 1998 IN 99-10 Degradation of Prestressing Tendon Systems in Prestressed Concrete Containments, April 1999
IN 06-01 Torus Cracking in a BWR Mark-I Containment, January 2006 ISG 06-01 Aging Management Program for Inaccessible Areas of BWR Mark-I Containment Drywell shell, September 2006
Inspection Procedures IP 62002 Inspection of Structures, Passive Components, and Civil Engineering Features at Nuclear Power Plants, Dec. 1996
IP 62003 Inspection of Steel and Concrete Containments at Nuclear Power Plants, June 1997 Regulatory Guides
RG 1.35 lnservice Inspection of Ungrouted Tendons in Prestressed Concrete Containments. Rev. 1 (1974), 2 (1976), 3 (1990)
RG 1.35.1 Determining Prestressing Forces for lnservice Inspection of Prestressed Concrete Containments: Draft (1979), final (1990)
RG 1.90 lnservice Inspection of Prestressed Concrete Containments with Grouted Tendons: (1977).
RG 1.107 Qualification of Cement Grouting for Prestressing Tendons in Prestressed Concrete Containments: (1977)
RG 1.136 Materials, Construction and Testing of Concrete Containments (Endorsement of ASME Section III/Div. 2 (or ACI 359): (1981)
RG 1.142 Safety-Related Concrete Structures for Nuclear Power Plants (Other than Reactor Vessels and Containments): (1981)
Technical Support to the principal coordinators of 10 CFR 50.55a, (Codes and Standards) Revisions on endorsing Subsections IWE/IWL (ISI of Containments) of the ASME Code: 1994 to
Present PROFESSIONAL AND COMMUNITY ACTIVITIES Participation in National and International Standards Organizations Member of the following NSO and INSO Committees: American Institute of Steel Construction (AISC) Chairman: Nuclear Specification Committee (AISC/ANSI N690)
Member: Building Specification Committee Advisory: Seismic Provisions Committee American Concrete Institute (ACI) 349 Committees Member: Main committee Member: Subcommittee 1 on General Requirements, Materials and QA Member: Subcommittee 2 on Design American Society of Mechanical Engineers (ASME): Member: Working Group on lnservice Inspection of Concrete and Steel Containments (Subsections IWE and IWL of ASME Section XI Code) Member: ASME/ACI Joint Committee on Design, Construction, Testing and Inspection of Concrete Containments and Pressure Vessels Member: RILEM Task Committee 160-MLN: Methodology for Life Prediction of Concrete Structures in Nuclear Power Plants Member: Federation Internationale du Beton (FIB) Task Group 1.3: Containment Structures Consultant to IAEA on Concrete Containment Database (2001 to 2005)
PROFESSIONAL MEMBERSHIPS Professional Engineer: State of Ohio, State of Maryland Fellow - American Concrete Institute Fellow - American Society of Civil Engineers Professional Member - Post-tensioning Institute
COMMUNITY ORGANIZATIONS - SERVICES Member- Montgomery County Energy and Air-Quality Advisory Committee (1995 to 2001)
Science Fair Judge (Montgomery County) - 1994-2001 Member-Architectural Committee - Hickory Crest, Columbia, Association Peer reviewer of number of papers to be published in ASCE Material Journal, NED Periodicals, and ACI International.
PUBLICATIONS/PRESENTATIONS
- 1. Ashar, H., Terao, D., Imbro, E.:
AReliability of Containment and Risk-Informed Decision Making B A Perspective,@ Presented at SMiRT17 International Conference in Prague, Czech Republic, August 2003.
- 2. Ashar, H., Imbro, E, Terao, D.: Integrated Leak Rate Testing of Containments - A Regulatory Perspective, Presented by Eugene Imbro at ICONE11 in Tokyo, Japan, April
2003.
- 3. Ashar, H.: Inspection of Containment Structures in the U.S.A. Presented at the 16 th International Conference on Structural Mechanics in Reactor Technology, Washington DC. August 12-17, 2001.
- 4. Kotzalas, M., Ashar, H.: Regulatory Issues Involved in the Use of the ASME XI, IWE/IWL, Presented at the ASME Pressure Vessel and Piping Conference, Atlanta, GA.
July 2001.
- 5. Ashar H., Kotzalas, M.: Implementation of Containment Inspection Rule, 10 CFR Part 50.55a, Presented at the ASME Pressure Vessel and Piping Conference, Atlanta, GA.
July 2001.
- 6. Ashar, H.: Implications of Concrete Structure Degradations in Nuclear Power Plants, Proceedings of the International RILEM Conference on Life Prediction and Aging Management of Concrete Structures, Cannes, France, October 16-18, 2000.
- 7. Ashar, H., Bagchi, G.: "Monitoring Degradation of Concrete Structures in U.S. Nuclear Power Plants," Proceedings of the 8 th International Conference (Sponsored by RILEM) on "Life Management and Aging Management of Concrete Structures," Bratislava, Slovakia, July 1999.
- 8. Ashar, H., Bagchi, G.: "Implementation of Maintenance Rule for Structures," Proceedings of the 7" symposium on Current Issues Related to Structures, Systems, and Piping, North Carolina State University, Raleigh, NC, December 1998 (Published in Nuclear Engineering and Design in Nov. 1999).
- 9. Ashar, H., Costello, J., Graves, H.: "Prestress Force Losses in Containments of U.S. Nuclear Power Plants," Proceedings of the Joint WANO-PCIOECD-NEA Workshop on Prestress Loss in Nuclear Containments, Poitier, France, August 1997.
- 10. Ashar, H., Bagchi G.: "Safety Related Nuclear Power Plant Structures - Assessment of lnservice Conditions," NUREG 1522, U.S. Nuclear Regulatory Commission, Washington D.C., 20555, May 1995.
- 11. Ashar, H., Jeng, D.: "Degradation of Passive Components in U.S. Nuclear Power Plants," Proceedings of the 6th Symposium on Current Issues Related to Structures, Systems, and Piping, North Carolina State University, Raleigh, NC, December 1996.
- 12. Ashar, H., Jeng, D.: "Performance of Structures in Nuclear Power Plants," Paper X/2, Proceedings of the 5th Symposium on Current Issues Related to Structures, Systems, and Piping, Orlando, Fl., December 1994.
- 13. Ashar, H., Naus, D., Tan, C. P.: "Prestressed Concrete in U.S. Nuclear Power Plants," Concrete International, American Concrete Institute, Detroit, Michigan, Part I in May 1994, Part 2 in June 1994.
- 14. Jeng, D., Bagchi, G., Ashar, H.: "Structural Issues Related to Containment Performance in Advanced Reactors," Proceedings of the Second ASME/JSME Conference on Nuclear Engineering, San Francisco, CA, March 1993.
- 15. Ashar, H., Tan, C. P.: "Inservice Performance of Containment Structures - U.S.
Experience," Proceedings of the 11 th Conference of Structural Mechanics in Reactor Technology (SMIRT), Tokyo, Japan, August 1991.
- 16. Tan, C. P., Ashar, H.: "Modifications of Concrete Containments for Steam Generator Replacement-Regulatory Considerations," Proceedings of SMIRT 11th, Tokyo, Japan, August 1991.
- 17. Ashar, H., Jeng, D.: "Effectiveness of lnservice Requirements for Prestressed Concrete Containments," Proceedings of the 2nd International Conference on Containment Design and Operation, Toronto, Ontario, Canada, October 1990.
- 18. Ashar, H., Degrassi, G.: "Design and Analysis of Free standing Spent Fuel Racks in Nuclear Power Plants," Proceedings of the 10 th SMIRT Conference, Anaheim, CA., August 1989.
- 19. Bagchi, G., Jeng. D., Ashar, H.: "Proposed Modifications of NRC's Standard Review Plan for Seismic Analysis," Proceedings of the 2 nd Symposium on Current Issues Related to NPP Structures, Systems, and Piping, Orlando, Fl., Dec. 1988.
- 20. Ashar, H., Jeng, D.: "Spent Fuel Storage - A Regulatory Perspective," Presented at 1988 ASME Joint Power Generation Conference, Philadelphia, Pa. September 1988.
- 21. Richardson, J., Ashar, H.: "Regulatory Perspective on Containment Performance," Presented at MITI/NRC Conference on Nuclear Technology, Tokyo, Japan, Dec. 1987.
- 22. Ashar, H., Naus, D.: "Overview of the Use of Prestressed Concrete in U.S. Nuclear Power Plants," Nuclear Engineering and Design, Val. 75, North Holland Publishing Company, August 1983.
- 23. Dougan, J., Ashar, H.: "Evaluation of Grease Performance in Prestressed Concrete Containments," Proceedings of 6 th SMIRT Conference, Chicago, 11. August 1983.
James A. Davis, Ph. D Statement of Professional Qualifications CURRENT POSITION:
Senior Materials Engineer Division of License Renewal, Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Commission, Rockville, MD EDUCATION:
B. Met. E., The Ohio State University, 1965, Metallurgical Engineering M.S., The Ohio State University, 1965, Metallurgical Engineering Ph.D., The Ohio State University, 1968, Metallurgical Engineering
SUMMARY
Over 39 years of experience in material engineer ing with over 20 years of experience in the nuclear power industry. Significant experience in the following areas:
Materials Engineering Corrosion and Control Protective Coatings and Linings Welding and Special Repair Processes License Renewal Nuclear Facilities Audits Allegations Reviews of Navy Submarine Power Plant Designs Quality Assurance ASME Code Committees ASTM D-33 Committee on Coatings for Power Generation Facilities
EXPERIENCE:
U.S. Nuclear Regulatory Commission, 11/11/1990 - Present 11/13/2005 to Present - Senior Materials Engineer, Division of License Renewal, Office of Nuclear Regulatory Research
Audit Team Leader for the license renewal safety audit at the Pilgrim Nuclear Power Station Audit Team Member for the license renewal safety audit at the Oyster Creek Generating Station
12/15/2001 - 11/13/ 2005 - Senior Materials Engineer in the Division of Engineering Technology, Office of Nuclear Regulatory Research Program Manager on the Steam Generator Tube Integrity Program overseeing work conducted at Argonne National Laboratory Acting Program Manager for Non-Destructive Examination research at Pacific Northwest National Laboratory 11/11/1990 - 12/15/2001 - Technical Reviewer in the Materials and Chemical Engineering Branch, Chemical Engineering and Metallurgy Section, Division of Engineering, Office of Nuclear Reactor Regulation.
Coatings for nuclear power plants, License renewal for Calvert Cliffs, Oconee, Arkansas Nuclear One, Hatch, and Turkey Point.
Threaded fastener issues (such as stress corrosion cracking, boric acid corrosion, and fatigue),
chemical decontamination, Boiling Water Reactor internals cracking, pump and valve internals cracking, pipe integrity issues, corrosion behavior for dry cask storage, and interaction of coatings with spent fuel water, Coordinated the responses to a generic letter on containment coatings for nuclear power plants.
NRC representative to ASTM D-33 on coatings for power generation facilities.
Member of the Board of Directors for the National Board of Registration for Nuclear Safety Related Coating Engineers & Specialists.
Member of ASME on Welding and Special Repair Processes.
Member of an Augmented Inspection Team at Palisades on fuel handling problems, Point Beach on the hydrogen burn as a result of interactions between borated water and the inorganic Zinc coating during dry cask loading operations and Davis-Besse on the Boric acid corrosion of he vessel head.
Contract Technical Monitor and Project Officer for numerous contracts at Brookhaven National Labs.
Technical reviewer for the design of the Navy Seawolf Submarine and the Virginia Class Submarine Reviewer on the DOE project to produce tritium in a commercial reactor (Watts Bar) Numerous presentations to senior NRC management including the Chairman, the Executive Director for Operations, the Committee to Resolve Generic Issues, and the Advisory Committee on Reactor Safety and Safeguards.
Testified before Representative Dingle's staff on the safety of fasteners in nuclear power plants as a result of concerns raised by a private citizen.
Polyken Division of the Kendall Company. Senior Research Associate, 1981 - 1990:
Responsible for Technical Marketing for the pipeline coating division providing technical data and reports to domestic and international customers. Company representative to the National Association of Corrosion Engineers, the American Water Works Association coatings committees, and ASTM coating committees.
Arthur D. Little, Senior Consultant, 1979 - 1981:
Consultant to DOE on Defense Nuclear Waste issues and Waste Tank corrosion issues.
Consultant on numerous commercial contracts on corrosion, coating, metallurgical, and plating issues.
Allied Tube and Conduit Corp., Director of Research, 1978-1979:
Responsible for research and development for metallurgical tube forming, welding, chemical cleaning of steel, galvanizing, surface treatment and coating of electrical conduit, fence posts, and specialty tubing. Responsible for Quality Assurance and
Process Control.
Allegheny Ludlum Steel Corp., Research Specialist, 1976-1978:
Responsible for customer service for use of stainless steels in corrosive service. Responsible for conducting failure analysis. Conducted research on corrosion mechanisms for stainless steels.
Bell Aerospace Company, Senior Research Scientist, 1970-1976:
Program Manager on numerous Navy spons ored programs involving corrosion of aluminum alloys, stainless steels, and titanium alloys in high velocity sea water for the Navy=s high performance ships program. Conducted research on corrosion fatigue, stress corrosion, and fouling in sea water. Conducted research on the compatibility of rocket fuels and oxidizers with fuel handling equipment.
U.S, Steel Corporation, Senior Research Engineer, 1968-1970:
Conducted research on the mechanism of pitting/crevice corrosion, stress corrosion cracking, hydrogen embrittlement, and intergranular corrosion using electrochemical techniques, transmission electron microscopy, optical microscopy, and scanning electron microscopy.
Mark Hartzman, Ph. D.
Statement of Professional Qualifications CURRENT POSITION:
Senior Mechanical Engineer Mechanical and Civil Engineering Branch (EMCB)
Division of Engineering Office of Nuclear Reactor Regulation
EDUCATION:
! B.S. Mechanical Engineering, The City College of New York, New York, N. Y., 1959.
! MS Mechanical Engineering, University of Washington, Seattle, WA, 1963. Major: Engineering Mechanics.
! Ph. D., Mechanical Engineering, University of California, Davis, CA, 1970. Major: Engineering Mechanics.
SUMMARY
- Over 48 years of experience in Engineering Mechanics and Structural Analysis. Over 32 years experience in Nuclear Regulatory review and evaluation. Significant review experience in the following areas:
! Finite element analysis - solid mechanics, statics and dynamics
! Structural seismic analysis methodology
! Structural computer programs
! Piping analysis methodology and criteria
! ASME Section III Code design criteria
! License renewal EXPERIENCE:
U.S. Nuclear Regulatory Commission, 06/75 - present Wide variety of assignments over this time period. Representative assignments have consisted or consist of the following:
! Review of a wide variety of license amendment requests, requiring in-depth technical evaluation of licensee calculational methodology and procedures.
! Evaluation of licensee responses to I&E Bulletin 79-07, ASeismic Stress Analysis of Safety Related Piping.
@ Co-author of reports NUREG/CR 1677, APiping Benchmark Problems
@, Volumes 1 and 2.
! Development of acceptance criteria for I&E Bulletin 79-02, A Pipe Support Base Plate Design Using Concrete Expansion Anchor Bolts.
@
! Evaluation of industry acceptance criteria and plant responses to I&E Bulletin 88-08 AThermal Stresses in Piping Connected to Reactor Coolant Systems.
@ ! Evaluation of license renewal requests in the area of time limited aging analysis of ASME Section III metal components (metal fatigue) for the following plants:
Palisades, St. Lucie Browns Ferry, V. C. Summer Brunswick, ANO-2
! Evaluation of allegations:
Example: Deficiencies in piping and base plate design at the Diablo Canyon NPP, 1982-1984.
! Revision and updating of the Standard Review Plan within the scope of the EMCB. ! Evaluation of ASME Section III code cases for acceptance and listing in Regulatory Guide 1.84.
! Assistance to NRC Regions with technical resolution of inspection reports and differing professional opinions (DPOs):
Example: Fermi HVAC duct safety under tornado loading. Resulted in NRC Regulatory Issue Summary (RIS) 2006-23, A Post-tornado Operability of ventilating and Air Conditioning Systems Housed in Emergency Diesel generating Rooms.
@ Example: In 2006, as a member of a Region II Differing Professional Opinion DPO panel, performed the technical evaluation of a DPO regarding Oconee pipe whip structural integrity.
! Participation in ASME Section III Code working groups and committees since 1974. As the NRC representative, participated or currently participate in the following groups:
Task Group on Faulted Conditions Working Group on Dynamic and Extreme Loading Conditions Working Group on Vessels (current)
Working Group on Methods Development (current)
The Lawrence Livermore National Laboratory, Livermore, CA, 1973-1975 (On loan to the USAEC, Mechanical Engineering Branch (MEB))
! Review of new plants construction license applications.
! Assistance with development of the Standard Review Plan within the scope of the MEB. ! Review of ASME Code Section III faulted condition acceptance criteria.
The Lawrence Livermore National Laboratory, Livermore, CA, 1963-1973.
Computer-based design and analysis of equipment used in testing of nuclear weapons.
Ph. D. dissertation based on this work.
The Boeing Company, Seattle, WA, 1959 - 1963
! Design and stress analysis of pilotless aircraft and helicopter engines.
! Research in the fabrication of aircraft components using explosives. MS thesis based on this work.
Timothy L. O'Hara Statement of Professional Qualifications CURRENT POSITION:
Reactor Inspector U.S. Nuclear Regulatory Commission, Region 1 Office, Division of Reactor Safety, Plant Support Branch 2
EDUCATION:
Bachelor of Science in Physics, 1970, Saint Francis University, Loretto, PA U.S. Naval Officer Candidate School, 1971, Newport, RI U.S. Naval Nuclear Power Program, 1972, Bainbridge, MD and Windsor, CT Master of Science in Engineering Management, 1980, University of Pittsburgh, Pittsburgh, PA Master of Business Administration, 1988, Temple University, Philadelphia, PA
EXPERIENCE:
U.S. Nuclear Regulatory Commission, June 2002 - Present Reactor Inspector, Region I, Plant Support Branch 2, King of Prussia, PA, October 2005 to Present Conduct engineering inspections and assess licensee performance at commercial nuclear power plants throughout the northeast US. Inspections include Inservice Inspections, Plant Component Replacement Inspections (Steam G enerators, Pressurizers, and Reactor Vessel Closure Heads), License Renewal Aging Management Inspections, Plant Modifications, Problem Identification and Resolution, Resident Inspector coverage, and Safety System Design Inspections.
Training in ASME Code, Eddy Current Testing, Fracture Mechanics, welding techniques and Construction Procedures.
Reactor Inspector, Region I, Engineering Branch I, King of Prussia, PA, October 2004 - September 2005 Conduct engineering inspections and assess licensee performance at commercial nuclear power plants throughout the northeast US. Inspections include Plant Modifications, Problem Identification and Resolution, Fire Protection, In Service Inspection, Resident Inspector coverage, and Safety System Design Inspections.
Training in Digital Circuits, Electrical System Coordination and Short Circuit Calculations. Reactor Inspector, Region I, Electrical Branch, King of Prussia, PA, June 2002 - September 2004 Conduct engineering inspections and assess licensee performance at commercial nuclear power plants throughout the northeast US. Inspections include Plant Modifications, Problem Identification and Resolution, Fire Protection, In Service Inspection, Resident Inspector coverage, and Safety System Design Inspections.
Training in BWR and PWR plant design and operation.
Completed the following inspections during the past five years:
Salem U1, Inservice Inspection, September 2004, Team Lead Indian Point U2, Inservice Inspection, November 2004, Team Lead
Ginna, Inservice Inspection, March 2005, Team Lead Salem U2, Inservice Inspection, April 2005, Team Lead Beaver Valley U1, Stream Generator Replacement, January - June 2006, Team Lead Beaver Valley, SSDI, August 2002 Calvert Cliffs, Modifications & 50.59 Inspection, December 2002 Vermont Yankee, Modifications & 50.59 Inspection, April 2003 Millstone U2 & U3, Modifications & 50.59 Inspection, June 2003 Nine Mile Point U1 & U2, Modifications & 50.59 Inspection, August 2003 Salem, EDG Turbocharger Special Inspection, September 2003 Fitzpatrick, SSDI, October 2003 Salem U1, Inservice Inspection, September 2003 Ginna, Triennial Fire Protection Inspection, November 2003 Oyster Creek, Triennial Fire Protection Inspection, January 2003 Indian Point U2, Triennial Fire Protection Inspection, January 2004 Vermont Yankee, Triennial Fire Protection Inspection, December 2004 Indian Point U3, Triennial Fire Protection Inspection, February 2005 Ginna, License Renewal Inspection, Scoping & Screening, August 2003 Millstone, License Renewal Aging Management Inspection, September 2004 Indian Point U2, Modifications & 50.59 Inspection, January 2005 Nine Mile Point U1 & U2, License Renewal Aging Management Inspection, February 2005 Oyster Creek, License Renewal Aging Management Inspection, March 2006 Oyster Creek PI&R Team Inspection, May 2004 Hope Creek, PI&R Team Inspection, December 2005 Pilgrim, License Renewal Aging Management Inspection, September 2006 Oyster Creek License Renewal Commitment Inspection, October 2006 Vermont Yankee, License Renewal Aging Management Inspection, February 2007 Calvert Cliffs, PI&R Sample (460v breakers), June 2004 Salem PI&R Sample (CC-17 valve), June 2004 Ginna PI&R Sample (Human Performance), July 2006 Salem PI&R Sample (Auxiliary Building Ventillation - Charcoal Filters), June 2005 Peach Bottom PI&R Sample ( Corrective Actions), July 2006 Salem PI&R Sample (Corrective Actions), September 2006 Oyster Creek, Resident Backfill, July 2003 Salem Resident Inspector Backfill, June 2004 Hope Creek, Inservice Inspection, April 2006 Peach Bottom U2 & U3, PI&R Sample (Torus Corrosion), July 2006 Salem U2 Inservice Inspection, October 2006
Susquehanna U1, Inservice Inspection, March 2007 Salem U1, Inservice Inspection, April 2007
NRC TRAINING COURSES COMPLETED:
Power Plant Engineering Effective Communication For NRC Inspectors Media Training Workshop
Expectations For Inspectors
PRA Basics For Regulatory Applications Westinghouse 100 Technology Gathering Information For Inspectors
PRA Techniques and Regulatory Perspectives Root Cause/Incident Investigation Workshop Allegations Training - Classroom Ethics Orientation Conducting Inspections GE BWR/4 Technology GE BWR/4 Advanced Technology GE BWR/4 Simulator Field Techniques And Regulatory Processes Ethics Laws & Rules For Employees
Fire Protection For Power Plants Response Technical Manual Training SNE 594, Westinghouse Station Nuclear Engineers Training Improving Employment Applications Industrial & Commercial Power Distribution Systems Digital I & C Training Low Voltage Protection Course Eddy Current Testing Eddy Current & UT Testing of RV Head Penetrations, Wesdyne GE BWR/4 Simulator Refresher Training American Concrete Institute Seminar, Inspecting Concrete Structures Fracture Mechanics Training Construction Inspector Training ASME B&PV Code,Section VIII Denton Vacuum, LLC, June 1997 to February 2002 Operations Manager, Vacuum Equipment Division, Moorestown, NJ Responsible for material management, manufacturing, assemble and testing of complex vacuum deposition (thin film) equipment and systems for this privately held company.
Scott Specialty Gases, September 1993 to January 1997 General Manager, High Pressure Technology - Plumsteadville, PA Total business responsibility for the turnaround of high pressure cylinder manufacturing and startup of a custom equipment product line. Establishment of specialty innovative, custom gas handling and distribution equipment. Sales, manufacturing, new product development, and customer service responsibility.
Westinghouse Electric Corporation, December 1975 to August 1993 District Manager , Philadelphia Operations Center - 1989-1993 Total business responsibility for the Engineering Services Division's Philadelphia Region. Performed commercial electrical services and electrical equipment installation. Responsible for sales, customer service, and engineering services for all industrial sectors.
Manager, Nuclear Services Operations, Moorestown, NJ - 1985-1989 Total P&L responsibility for custom manufacturing decontamination and mobile cleaning services. Directed a staff of 5 managers and 150 technicians. Integrated an acquired subsidiary company into an existing corporate division. Manager, Mechanical Projects, Monroeville, PA - 1981-1985 Field Service responsibility for reactor internals repairs for commercial power plants. Split pin replacement, reactor upflow conversion, spent fuel rack replacement, foreign object search and retrieval, and miscellaneous mechanical repairs. Extensive work with utility representatives, Westinghouse Engineering and research groups. Managed 22 field engineers and 75 field service technicians . Site Manager, Steam Generator Replacement, Surry, VA - 1979-1981 Westinghouse site representative for SG replacement. Responsible for daily contact between utility and Westinghouse engineering, manufacturing and field service resources. Extensive involvement in mechanical problems, welding issues, and plant startup.
Nuclear Fuel Licensing Engineer, Monroeville, PA - 1977 -1979 Lead the Westinghouse effort on reload core licensing. Extensive involvement with utilities and internal Westinghouse Fuel and Engineering Divisions.
Senior Field Service Engineer , Churchill, PA - 1975-1977 Conducted SG eddy current inspections, SG sludge lancing, and SG weld repairs at Westinghouse commercial nuclear power plant. Extensive work with utility representatives and Westinghouse Engineering and Research groups.
U. S. Navy, September 1970 to November 1975 Completed Navy Basic Training and Electronic Technician Class A Training. Attended Officer Candidate School and Naval Nuclear Power Training. Served as a junior engineering office on board USS Seahorse and USS Sam Houston. Served as Electrical Officer, Damage Control Assistant, Ship's Diving Officer, Subsafe Officer, Engineering Plant Watch Officer. Completed extensive ship overhaul and refueling.
PROFESSIONAL MEMBERSHIPS:
American Society of Mechanical Engineers American Nuclear Society Beta Gamma Sigma Society of Manufacturing Engineers HONORS AND AWARDS:
Frank Castelli Academic Scholarship
Saint Francis University Physics Award Officer Candidate School, Distinguished Naval Graduate Temple University Executive MBA Selection, Westinghouse Electric Corporation Beta Gamma Sigma Distinguished Scholar, Temple University NRC Team Award, December 2002, Salem Special Inspection NRC Performance Award, Spring 2003 NRC Performance Award, December 2004 NRC Performance Award, December 2005 NRC Performance Award, December 2006
Staff Exhibit 1
Safety Evaluation Report Related to the License Renewal of Oyster Creek Generating Station Docket No. 50-219 AmerGen Energy Company, LLC Manuscript Completed: March 2007 Date Published: April 2007 Division of License Renewal Office of Nuclear Reactor Regulation U.S. Nuclear Regula tory Commission Washington, DC 20555-0001
1-1S E CT I ON 1
I NT RODUCT I ON A ND GE NE RA L DI S CUS S I ON 1.1 Introd uctionT hi s do cum ent i s a s af et y ev al uat i on r epor t (SE R) on t he l i cens e r enewal appl i cat i on (LR A) f or O y st er C r eek G ener at i ng St at i on (O C G S), as f i l ed by Am er G en Ener gy C om pany , LLC (A m e rG e n o r th e a p p li c a n t). B y l e tte r d a te d J u ly 2 2 , 2 0 0 5 , A m e rG e n s u b m itte d its a p p li c a tio n to t he U.S. N ucl ear R egul at or y C om m i ss i on (N R C) f or r enewal of t he O C G S oper at i ng l i cens e f or an addi t i onal 20 y ear s. T he NR C st af f (t he s t af f) pr epar ed t hi s r epor t , whi ch s um m ar i z es t he r esul t s of i t s s af et y r ev i ew of t he LRA f or com pl i ance wi t h t he r equi r em ent s of T i t l e 10, Par t 54, of t he C ode of Feder al R egul at i ons (10 CF R Par t 54), "R equi r em ent s f or R enewal of O per at i ng L i c e n s e s f o r Nu c l e a r P o w e r P l a n t s." Th e NR C l i c e n s e r e n e w a l p r o j e c t ma n a g e r f o r t h e OCGS l i cens e r enewal r ev i ew i s Donni e J. Ashl ey. Mr. Ashl ey can be c ont act ed by t el ephone at 3 0 1-4 1 5-3 1 9 1 o r b y e le c tro n ic m a il a t dj a1@nr c.gov. Al t er nat i v el y , wr i t t en c or r espo ndenc e m ay be se nt t o t he f ol l ow i ng a ddr ess: Li cens e R enewal and Env i r onm ent al I m pact s Pr ogr am U.S. N ucl ear R egul at or y C om m i ss i on W ashi ngt on, D.C. 20555-0001 At t en t i on: Donn i e J. As hl ey , Mai l St op 0-11 F1 I n i t s Jul y 22, 200 5, subm i t t al l et t er , t he a ppl i cant r equ est ed r ene wa l of t he o per at i ng l i cense i ss ued und er Sect i on 104b (O per at i ng Li cens e N o. D PR-16) of t he At om i c Ener gy Act of 1954, as a m ended, f or O C G S f or a per i od of 20 y ear s be y ond t he c ur r ent l i cens e ex pi r at i on dat e of m id n ig h t A p r il 9 , 2 0 0 9. O C G S is lo c a te d in L a c e y T o w n s h ip , O c e a n C o u n ty, N e w J e r s e y, appr ox i m at el y t wo m i l es s out h of t he c om m uni t y of For ked R i v er , t wo m i l es i nl and f r om t he shor e of Bar negat Bay , and ni ne m i l es s out h of T om s Ri v er , N ew Jer sey. T he NR C i ss ued t he O C G S const r uct i on per m i t on Decem ber 15, 1964, and t he O C G S oper at i ng l i cens e on J ul y 2, 1991. O C G S i s a s i ngl e uni t f aci l i t y wi t h a s i ngl e-cy cl e, f or ced-ci r cul at i on boi l i ng wat er r eact or (BW R)-2 and a Mar k 1 c ont ai nm ent. T he nuc l ear st eam sup pl y sy st em was f ur ni shed by G ener al El ect r i c (G E) and t he bal ance of t he pl ant was o r i gi nal l y des i gned an d co nst r uct ed by Bur ns & R oe. O C G S's l i cens ed power out put i s 19 30 m egawat t t her m al wi t h a gr oss el ect r i cal o u tp u t o f a p p ro x i m a te l y 6 1 9 m e g a w a tt e l e c tri c. T h e u p d a te d fin a l s a fe ty a n a l y s i s re p o rt (U FS AR) con t ai ns d et ai l s c once r ni ng t he pl ant and t he s i t e.T h e li c e n s e re n e w a l p ro c e s s c o n s is ts o f tw o c o n c u rre n t re v ie w s: (1) a te c h n ic a l re v ie w o f s a f e ty i ss ues and (2) an env i r onm ent al r ev i ew. T he NR C r egul at i ons f ound i n 10 CFR Par t s 54 and 51 , re s p e c ti v e l y , s e t fo rth th e re q u i re m e n ts a g a i n s t w h i c h l i c e n s e re n e w a l a p p l i c a ti o n s a re r ev i ewed. T he s af et y r ev i ew f or t he O C G S l i cens e r enewal i s ba sed on t he appl i cant's LRA and r e s p o n s e s t o t h e s t a f f's r e q u e s t s f o r a d d i t i o n a l i n f o r ma t i o n. Th e a p p l i c a n t s u p p l e me n t e d i t s L RA and pr ovi ded cl ar i f i cat i ons t hr oug h i t s r espo nses t o r equ est s f or add i t i ona l i nf or m at i on i n au di t s, m eet i ngs, and do ck et ed c or r espo ndenc e. U nl ess ot her wi se n ot ed, t he s t af f r ev i ewed and cons i der ed i nf or m at i on s ubm i t t ed t hr ough Decem ber 15, 2006, and af t er t hi s da t e on a cas e-by-cas e bas i s de pendi ng on t he s t age of t he s af et y r ev i ew and on t he v ol um e and com pl ex i t y of t he i nf or m at i on. T he publ i c m ay v i ew t he LRA and al l per t i nent i nf or m at i on and m at er i al s, i ncl udi ng t he UF SA R , at t he NR C Publ i c Docum ent R oom on t he f i r st f l oor of O ne 1-2 W hi t e Fl i nt N or t h, 11555 R ock v i l l e Pi ke, R ock v i l l e, MD 20852-2738 (301-415-4737 /800-397-4209), and at t he Lac ey Br anch - O cean C ount y Li br ar y , 10 East Lac ey R oad, For ked R i v er , N J 08 731. I n addi t i on, t he publ i c m ay f i nd t he LRA , as we l l as m at er i al s r el at ed t o t he l i c e n s e r e n e w a l r e vi e w , o n t h e N R C W e b S i t e a t w w w.n r c.g o v.T hi s SER sum m ar i z es t he r esul t s of t he s t af f's s af et y r ev i ew of t he LRA and de sc r i bes t he t echn i cal det ai l s c onsi der ed i n ev al uat i ng t he s af et y asp ect s of t he pr opos ed oper at i on f or an addi t i onal 20 y ear s be y ond t he t er m of t he c ur r ent oper at i ng l i cens e. T he s t af f r ev i ewed t he LR A i n ac cor danc e wi t h N R C r egul at i ons and t he gui danc e of N U R EG-1800, R ev i si on 1,"S t and ar d R evi ew P l an f or R evi ew of Li cense R ene wa l A ppl i cat i ons f or N ucl ear P ow er P l ant s"(S R P-L R), d a te d S e p te m b e r 2 0 0 5. SE R Sect i ons 2 t hr ough 4 addr ess t he s t af f's r ev i ew and ev al uat i on of l i cens e r enewal i ss ues cons i der ed dur i ng t he r ev i ew of t he appl i cat i on. Sect i on 5 i s r eser v ed f or t he r epor t of t he Adv i sor y C om m i t t ee on React or Saf eguar ds (AC R S). C oncl usi ons of t hi s r epor t ar e pr esen t ed i n Sect i on 6.SE R Appendi x A cont ai ns a t abl e t hat i dent i f i es t he appl i cant's c om m i t m ent s f or t he r enewal of t he o per at i ng l i cense. A ppe ndi x B pr ovi des a chr ono l ogy of t he p r i nci pal cor r espo nde nce bet ween t he s t af f and t he appl i cant on t he r ev i ew of t he appl i cat i on. Appendi x C i s a l i st of t he pr i nci pal con t r i but or s t o t hi s SER. Appendi x D i s a b i bl i ogr aphy of t he r ef er ence s i n su ppor t of t he r ev i ew.In a c c o rd a n c e w ith 1 0 C F R P a rt 5 1 , th e s ta f f p re p a re d a d ra f t, p la n t-s p e c ific s u p p le m e n t to N U R EG-1437, "G ener i c Env i r onm ent al I m pact St at em ent f or Li cens e R enewal of N ucl ear Pl ant s (G EI S)". T hi s s uppl em ent di sc uss es t he env i r onm ent al con si der at i ons f or r enewal of t he O C G S l i cens e. T he s t af f i ss ued Dr af t Suppl em ent 28 t o N U R EG-1437, "G ener i c Env i r onm ent al I m pact St at em ent f or Li cens e R enewal of N ucl ear Pl ant s, R egar di ng O y st er C r eek G ener at i ng St at i on, D r af t R epor t f or C om m ent ," i n Ju ne 2006.
1.2 License Renew al Bac kgroundPur suan t t o t he At om i c Ener gy Act of 1954, as a m ended, and NR C r egul at i ons, oper at i ng l i cens es f or com m er ci al power r eact or s ar e i ss ued f or 40 y ear s. T hese l i cens es c an be r enewed f or up t o 20 ad di t i onal y ear s. T he or i gi nal 40-y ear l i cens e t er m was s el ect ed on t he bas i s of e c o n o mi c a n d a n t i t r u s t c o n s i d e r a t i o n s r a t h e r t h a n o n t e c h n i c a l l i mi t a t i o n s; h o w e v e r , s o me i ndi v i dual pl ant and eq ui pm ent des i gns m ay hav e been engi neer ed f or an ex pect ed 40-y ear ser v i ce l i f e.I n 1982, t he s t af f ant i ci pat ed i nt er est i n l i cens e r enewal and he l d a wor ks hop on nucl ear power pl ant agi ng. T hi s wor ks hop l ed t he s t af f t o es t abl i sh a com pr ehens i v e pr ogr am pl an f or nuc l ear pl ant agi ng r esea r ch. W i t h t he r esul t s of t hat r esea r ch, a t echn i cal r ev i ew gr oup c oncl uded t hat m a n y a g in g p h e n o m e n a a re re a d il y m a n a g e a b le a n d p o s e n o te c h n ic a l i s s u e s th a t w o u ld pr ecl ude l i f e ex t ensi on f or nuc l ear power pl ant s. I n 1986, t he s t af f publ i shed a r eques t f or com m ent on a po l i cy st at em ent t hat woul d addr ess m aj or pol i cy , t echn i cal , and pr oced ur al i ssues r el at ed t o l i cense r ene wa l f or nucl ear pow er pl ant s.I n 1991, t he s t af f publ i shed t he l i cens e r enewal r ul e i n 10 CFR Par t 54 (t he Rul e), (56 FR 64943 dat ed Decem ber 13, 1991). T he s t af f par t i ci pat ed i n an i ndus t r y-spon sor ed dem onst r at i on 1-3 pr ogr am t o appl y t he Rul e t o a pi l ot pl ant and t o gai n ex per i ence nec ess ar y t o dev el op i m pl em ent at i on gui danc e. T o es t abl i sh a sc ope of r ev i ew f or l i cens e r enewal , t he Rul e def i ned a g e-r e l a t e d d e g r a d a t i o n u n i q u e t o l i c e n s e r e n e w a l; h o w e v e r , d u r i n g t h e d e mo n s t r a t i o n p r o g r a m, th e s ta ff fo u n d th a t a d v e rs e a g i n g e ff e c ts th a t o c c u r to p l a n t s y s te m s a n d c o m p o n e n ts a re m anaged dur i ng t he per i od of i ni t i al l i cens e. I n addi t i on, t he s t af f f ound t hat t he s cope of t he r ev i ew di d not al l ow suf f i ci ent cr edi t f or ex i st i ng pr ogr am s, par t i cul ar l y t he i m pl em ent at i on of t he M ai nt enanc e R ul e, whi ch a l so m anages pl ant-agi ng phen om ena. As a r esul t , t he s t af f am ended th e R u l e i n 1 9 9 5 (6 0 F R 2 2 4 6 1 d a te d M a y 8 , 1 9 9 5). T h e a m e n d e d R u l e e s ta b l i s h e d a re g u l a to ry pr oces s s i m pl er , m or e st abl e, and m or e pr edi ct abl e t han t he pr ev i ous R ul e. I n par t i cul ar , t he st af f am ended t he Rul e t o f ocus on m anagi ng t he adv er se e f f ect s of agi ng r at her t han on id e n tifyin g a g e-re la te d d e g ra d a tio n u n iq u e to li c e n s e re n e w a l. T h e s ta f f in iti a te d th e s e R u le c h a n g e s to e n s u re th a t im p o rta n t s ys te m s , s tru c tu re s , a n d c o m p o n e n ts (S S C s) w il l c o n tin u e to per f or m t hei r i nt ended f unct i ons dur i ng t he per i od of ex t ended o per at i on. I n addi t i on, t he r ev i sed R ul e cl ar i f i ed and si m pl i f i ed t he i nt egr at ed pl ant ass ess m ent pr oces s t o be c onsi st ent wi t h t he re v i s e d fo c u s o n p a s s i v e , l o n g-l i v e d s tru c tu re s a n d c o m p o n e n ts (S C s).I n par al l el wi t h t hese ef f or t s, t he s t af f pur sued a se par at e r ul em aki ng ef f or t and de v el oped an am endm ent t o 10 CFR Par t 51 t o f ocus t he s cope of t he r ev i ew of env i r onm ent al i m pact s of l i cense r ene wa l and f ul f i l l t he N R C's r espo nsi bi l i t i es un der t he N at i ona l E nvi r onm ent al P ol i cy Act of 1969.1.2.1 Saf et y R ev i ewLi cense r ene wa l r equ i r em ent s f or pow er r eact or s ar e ba sed o n t wo key pr i nci pl es: (1)
T h e re g u la to ry p ro c e s s is a d e q u a te to e n s u re th a t th e li c e n s in g b a s e s o f a ll c u rre n tly o p e ra tin g p la n ts p ro v id e a n d m a in ta in a n a c c e p ta b le le v e l o f s a f e ty, w ith th e p o s s ib le e x c e p tio n o f th e d e trim e n ta l e f f e c ts o f a g in g o n th e f u n c tio n a li ty o f c e rta in S S C s , a s w e ll as a f ew ot her saf et y-r el at ed i ss ues, dur i ng t he per i od of ex t ended o per at i on. (2)
T he pl ant-spec i f i c l i cens i ng bas i s m ust be m ai nt ai ned dur i ng t he r enewal t er m i n t he s a me ma n n e r a n d t o t h e s a me e x t e n t a s d u r i n g t h e o r i g i n a l l i c e n s i n g t e r m.I n i m pl em ent i ng t hese t wo pr i nci pl es, 10 CF R 54.4 def i nes t he s cope of l i cens e r enewal as i ncl udi ng t hose SS C s (1) t hat ar e sa f et y-r el at ed, (2) whose f ai l ur e co ul d af f ect saf et y-r el at ed f unct i ons, and (3) t hat ar e r el i ed on f or com pl i ance wi t h N R C r egul at i ons f or f i r e pr ot ect i on, env i r onm ent al qual i f i cat i on (EQ), pr ess ur i z ed t her m al sho ck (PT S), ant i ci pat ed t r ansi ent wi t hout s c ra m (A T W S), a n d s ta ti o n b l a c k o u t (S B O).P u rs u a n t to 1 0 C F R 5 4.2 1 (a), a n a p p li c a n t fo r a re n e w e d li c e n s e m u s t re v ie w a ll S S C s w ith in t he sco pe o f t he R ul e t o i den t i f y S C s subj ect t o an agi ng m ana gem ent r evi ew (A M R). T hose SC s s ubj ect t o an AM R per f or m an i nt ended f unct i on wi t hout m ov i ng par t s or wi t hout a ch ange i n co nf i gur at i on or pr oper t i es a nd ar e not sub j ect t o r epl acem ent bas ed on a qual i f i ed l i f e or speci f i ed t i m e pe r i od. A s r equ i r ed b y 10 C FR 54.21(a), an a ppl i cant f or a r ene we d l i cense m ust dem onst r at e t hat t he ef f ect s of agi ng wi l l be m anaged i n su ch a way t hat t he i nt ended f unct i on(s) of t hose SC s wi l l be m ai nt ai ned, con si st ent wi t h t he c ur r ent l i cens i ng bas i s (C LB), f or th e p e rio d o f e x te n d e d o p e ra tio n; h o w e v e r, a c tiv e e q u ip m e n t is c o n s id e re d to b e a d e q u a te ly m oni t or ed and m ai nt ai ned by ex i st i ng pr ogr am s. I n ot her wor ds, t he det r i m ent al ef f ect s of agi ng t hat m ay af f ect act i v e equi pm ent ar e m or e r eadi l y det ect abl e and c an be i dent i f i ed and cor r ect ed t hr ough r out i ne s ur v ei l l ance , per f or m ance m oni t or i ng, and m ai nt enanc e ac t i v i t i es. T he 1-4 s u rv e il la n c e a n d m a in te n a n c e a c tiv iti e s p ro g ra m s f o r a c tiv e e q u ip m e n t, a s w e ll a s o th e r a s p e c ts of m ai nt ai ni ng t he pl ant's de si gn and l i cens i ng bas i s, ar e r equi r ed t hr oughou t t he per i od of ex t ended o per at i on.Pur suan t t o 10 CFR 54.21(d), t he LRA i s r equi r ed t o i ncl ude a UFS AR sup pl em ent wi t h a sum m ar y des cr i pt i on of t he appl i cant's pr ogr am s an d ac t i v i t i es f or m anagi ng t he ef f ect s of agi ng and an ev al uat i on of t i m e-l i m i t ed agi ng anal y ses (T LAA s) f or t he per i od of ex t ended o per at i on.Li cens e r enewal al so r equi r es i dent i f i cat i on and updat i ng of T LAA s. D ur i ng t he des i gn phas e f or a pl ant , cer t ai n as sum pt i ons about t he l engt h of t i m e t hat t he pl ant can oper at e ar e i ncor por at ed i n to d e s i g n c a l c u l a ti o n s fo r s e v e ra l o f th e p l a n t's S S C s. I n a c c o rd a n c e w i th 1 0 C F R 5 4.2 1 (c)(1), t he appl i cant m ust ei t her sho w t hat t hese cal cul at i ons wi l l r em ai n v al i d f or t he per i od of ex t ended o per at i on, pr oj ect t he anal y ses t o t he end of t he per i od of ex t ended o per at i on, or dem onst r at e t hat t he ef f ect s of agi ng on t he i nt ended f unct i on(s) wi l l be ade quat el y m anaged f or t he per i od of ex t ended o per at i on.I n 2001, t he s t af f dev el oped an d i ss ued Regul at or y G ui de 1.188, "St andar d For m at and Cont ent f or Appl i cat i ons t o R enew Nucl ear Power Pl ant O per at i ng Li cens es." T hi s r egul at or y gui de endor ses N ucl ear Ener gy I nst i t ut e (N EI) 95-10, "I ndus t r y G ui del i ne f or I m pl em ent i ng t he R equi r em ent s of 10 CF R Par t 54 - T he Li cens e R enewal R ul e," dat ed Mar ch 2 001. N EI 95-10 d e ta il s a n a c c e p ta b le m e th o d o f im p le m e n tin g th e R u le. T h e s ta f f a ls o u s e d th e S R P-L R to r ev i ew t he appl i cat i on.I n t he LRA , t he appl i cant f ul l y ut i l i z ed t he pr oces s de f i ned i n N U R EG-1801, R ev i si on 1,"G e n e ri c A g i n g L e s s o n s L e a rn e d (G A L L) R e p o rt," d a te d S e p te m b e r 2 0 0 5. T h e G A L L R e p o rt pr ov i des t he s t af f wi t h a s um m ar y of st af f-appr ov ed agi ng m anagem ent pr ogr am s (AM Ps) f or t he a gi ng o f m any S C s subj ect t o an A M R. I f an a ppl i cant com m i t s t o i m pl em ent i ng t hese st af f-appr ov ed AM Ps, t he t i m e, ef f or t , and r esou r ces use d t o r ev i ew an app l i cant's LRA can be gr eat l y r educ ed, t her eby i m pr ov i ng t he ef f i ci ency and ef f ect i v enes s of t he l i cens e r enewal r evi ew pr ocess. T he G A LL R epo r t sum m ar i z es t he a gi ng m ana gem ent eval uat i ons, pr ogr am s, a n d a c tiv itie s c r e d ite d f o r m a n a g in g a g in g f o r m o s t o f th e S C s u s e d th r o u g h o u t th e in d u s tr y.T h e re p o rt a l s o s e rve s a s a re fe re n c e fo r b o t h a p p l i c a n t s a n d s t a ff r e vi e w e rs t o q u i c k l y i d e n t i fy AM Ps and ac t i v i t i es t hat t he s t af f det er m i ned c an pr ov i de adeq uat e agi ng m anagem ent dur i ng per i ods of ex t ended o per at i on.1.2.2 Envi r onm ent al R ev i ewP a rt 5 1 o f 1 0 C F R g o ve rn s e n vi ro n m e n t a l p ro t e c t i o n re g u l a t i o n s. I n D e c e m b e r 1 9 9 6 , t h e s t a ff r ev i sed t he env i r onm ent al pr ot ect i on r egul at i ons t o f aci l i t at e t he env i r onm ent al r ev i ew f or li c e n s e re n e w a l. T h e s ta f f p re p a re d th e G E IS to d o c u m e n t its e v a lu a tio n o f th e p o s s ib le env i r onm ent al i m pact s of r enewed l i cens es f or nuc l ear power pl ant s. For cer t ai n t y pes of env i r onm ent al i m pact s, t he G EI S est abl i shes gener i c f i ndi ngs appl i cabl e t o al l nuc l ear power pl ant s. T hese gener i c f i ndi ngs ar e co di f i ed i n Appendi x B t o Subpar t A of 10 CF R Par t 51.P ur suan t t o 10 C FR 51.53(c)(3)(i), an a ppl i cant f or l i cense r ene wa l m ay i ncor por at e t hese gener i c f i ndi ngs i n i t s en v i r onm ent al r epor t. I n ac cor danc e wi t h 10 CFR 51.53(c)(3)(i i), an env i r onm ent al r epor t m ust al so i ncl ude ana l y ses of env i r onm ent al i m pact s t hat m ust be e v a l u a te d o n a p l a n t-s p e c i fic b a s i s (i.e., C a te g o ry 2 i s s u e s).
1-5 I n ac cor danc e wi t h t he Nat i onal Env i r onm ent al Pol i cy Act of 1969 a nd t he r equi r em ent s of 1 0 C F R P a rt 5 1 , th e s ta f f re v ie w e d th e p la n t-s p e c ific e n v iro n m e n ta l i m p a c ts o f li c e n s e re n e w a l, in c lu d in g w h e th e r th e G E IS h a d n o t c o n s id e re d n e w a n d s ig n ific a n t in f o rm a tio n. A s p a rt o f its s c o p in g p r o c e s s , th e s ta f f h e ld a p u b lic m e e tin g N o v e m b e r 1 , 2 0 0 5 , in T o m s R iv e r , N e w J e r s e y, to id e n tify e n v iro n m e n ta l i s s u e s s p e c ific to th e p la n t. T h e d ra f t, p la n t-s p e c ific S u p p le m e n t 2 8 to t he G E I S , dat ed Ju ne 2 006 , docu m ent s t he r esul t s of t he e nvi r onm ent al r evi ew and i ncl ude s a p re li m in a ry re c o m m e n d a tio n o n th e li c e n s e re n e w a l a c tio n. T h e s ta f f h e ld a n o th e r p u b li c m eet i ng on J ul y 12, 2006, i n T om s Ri v er , N ew Jer sey , t o di sc uss dr af t G EI S S uppl em ent 28.A f te r c o n s id e rin g c o m m e n ts o n th e d ra f t, th e s ta f f p u b li s h e d th e f in a l, p la n t-s p e c ific G E IS S u p p le m e n t 2 8 , o n J a n u a ry 2 9 , 2 0 0 7.
1.3 Pri nci pal R ev iew M at te rsPar t 54 of 10 CF R des cr i bes t he r equi r em ent s f or r enewi ng oper at i ng l i cens es f or nuc l ear power pl ant s. T he st af f per f or m ed i t s t echn i cal r evi ew of t he L R A i n acco r dan ce w i t h N R C gui dan ce and t he r equi r em ent s of 10 CF R Par t 54. Sect i on 54.29 of 10 CF R set s f or t h t he s t andar ds f or r en ew i ng a l i c en s e. Thi s SER des c r i be s t he r es ul t s of t he s t af f's s af et y r ev i ew.Sect i on 54.19(a) of 10 CF R r equi r es l i cens e r enewal appl i cant s t o su bm i t gener al i nf or m at i on.Th e a p p l i c a n t p r o v i d e d t h i s g e n e r a l i n f o r ma t i o n i n L RA S e c t i o n 1. Th e s t a f f r e v i e w e d L RA Sect i on 1 an d f ound t hat t he appl i cant had s ubm i t t ed t he i nf or m at i on r equi r ed by 1 0 C F R 5 4.1 9 (a).S e c ti o n 5 4.1 9 (b) o f 1 0 C F R re q u i re s e a c h L R A to i n c l u d e "c o n fo rm i n g c h a n g e s to th e s ta n d a rd i ndem ni t y agr eem ent , 10 CF R 140.92, Appendi x B, t o ac coun t f or t he ex pi r at i on t er m of t he pr opos ed r enewed l i cens e." I n t he LRA , t he appl i cant st at ed t he f ol l owi ng r egar di ng t hi s i ss ue:T h e c u rre n t in d e m n ity a g re e m e n t (N o. B-3 7) f o r O ys te r C re e k s ta te s in A rtic le V II t hat t he agr eem ent sha l l t er m i nat e at t he t i m e of ex pi r at i on of t he l i cens es spec i f i ed i n I t em 3 of t he At t achm ent t o t he agr eem ent. I t em 3 of t he At t achm ent to th e in d e m n ity a g re e m e n t li s ts li c e n s e n u m b e r, D P R-1 6. A p p li c a n t re q u e s ts t hat any nec ess ar y con f or m i ng c hanges be m ade t o Ar t i cl e VI I and I t em 3 of t he A tta c h m e n t, a n d a n y o th e r s e c tio n s o f th e in d e m n ity a g re e m e n t a s a p p ro p ria te to ensu r e t hat t he i ndem ni t y agr eem ent con t i nues t o appl y dur i ng bot h t he t er m s of t he c ur r ent l i cens e and t he t er m s of t he r enewed l i cens e. Appl i cant under st ands t hat no c hanges m ay be nec ess ar y f or t hi s pu r pose i f t he c ur r ent l i cens e num ber i s r et ai ned.T he s t af f i nt ends t o m ai nt ai n t he or i gi nal l i cens e num ber upon i ss uanc e of t he r enewed l i cens e, i f appr ov ed. T her ef or e, con f or m i ng c hanges t o t he i ndem ni t y agr eem ent need n ot be m ade and th e re q u ire m e n ts o f 1 0 C F R 5 4.1 9 (b) h a v e b e e n m e t.S e c ti o n 5 4.2 1 o f 1 0 C F R re q u i re s e a c h L R A to c o n ta i n (a) a n i n te g ra te d p l a n t a s s e s s m e n t, (b) a desc r i pt i on of any C LB changes t hat occ ur r ed dur i ng t he s t af f's r ev i ew of t he LRA , (c) an e va l u a t i o n o f T L A A s , a n d (d) a U F S A R s u p p l e m e n t. L R A S e c t i o n s 3 , 4 , a n d A p p e n d i x B addr ess t he l i cens e r enewal r equi r em ent s of 10 CF R 54.21(a) and (c). LR A A ppendi x A as supp l em ent ed b y A m er G en l et t er s 213 0-06-203 54 a nd 2 130-06-202 58 co nt ai ns t he l i cense re n e w a l re q u i re m e n ts o f 1 0 C F R 5 4.2 1 (d).
1-6 Sect i on 54.21(b) of 10 CF R r equi r es t hat eac h y ear , f ol l owi ng s ubm i ss i on of t he LRA , and at l east t hr ee m ont hs be f or e t he sch edu l ed co m pl et i on o f t he st af f's r evi ew , t he a ppl i cant m ust s u b m it a n a m e n d m e n t to th e L R A th a t id e n tifie s a n y c h a n g e s to th e f a c il ity's C L B m a te ria ll y af f ect i ng t he c ont ent s of t he LRA , i ncl udi ng t he UF SA R sup pl em ent. T he appl i cant sub m i t t ed an updat e t o t he LRA , by l et t er dat ed J ul y 18, 2006, whi ch s um m ar i z es t he c hanges t o t he CLB t hat hav e oc cur r ed dur i ng t he s t af f's r ev i ew of t he LRA. I n a s ubse quent l et t er on Decem ber 3, 2006, as c or r ect ed by l et t er dat ed Decem ber 15, 2006, t he appl i cant sub m i t t ed an u pdat e t o t he L R A t o i n c o rp o ra t e c h a n g e s fro m t h e O c t o b e r 2 0 0 6 re fu e l i n g o u t a g e. T h e s e s u b m i s s i o n s s a t i s fy th e re q u i re m e n ts o f 1 0 C F R 5 4.2 1 (b).Sect i on 54.22 of 10 CF R 54.22 r equi r es t he LRA t o i ncl ude c hanges or addi t i ons t o t he t echn i cal spe ci f i cat i ons nece ss ar y t o m anage t he ef f ect s of agi ng dur i ng t he per i od of ex t ended oper at i on. I n LRA Appendi x D , t he appl i cant st at ed t hat i t had no t i dent i f i ed any t echn i cal spec i f i cat i on c hanges nec ess ar y t o su ppor t i ss uanc e of t he r enewed o per at i ng l i cens e f or O C G S. T hi s s t at em ent adequa t el y addr ess es t he r equi r em ent spe ci f i ed i n 10 CFR 54.22.T h e s ta f f e v a lu a te d th e te c h n ic a l i n f o rm a tio n re q u ire d b y 1 0 C F R 5 4.2 1 a n d 1 0 C F R 5 4.2 2 in acc or danc e wi t h N R C r egul at i ons and t he gui danc e pr ov i ded by t he SR P-LR. SE R Sect i ons 2, 3 , a n d 4 d o c u m e n t t h e s t a f f's e v a l u a t i o n o f t h e t e c h n i c a l i n f o r m a t i o n i n t h e L RA.As r equi r ed by 10 CF R 54.25, t he AC R S wi l l i ss ue a r epor t t o doc um ent i t s ev al uat i on of t he s ta f f's re v ie w o f th e L R A a n d a s s o c ia te d S E R. S E R S e c tio n 5 w il l i n c o rp o ra te th e A C R S re p o rt, once i t i s i ss ued. SE R Sect i on 6 do cum ent s t he f i ndi ngs r equi r ed by 10 CF R 54.29.T he f i nal , pl ant-spec i f i c G EI S S uppl em ent 28 wi l l doc um ent t he s t af f's ev al uat i on of t he env i r onm ent al i nf or m at i on r equi r ed by 10 CF R 54.23 and wi l l spe ci f y t he c onsi der at i ons r el at ed to re n e w in g th e li c e n s e f o r O C G S. T h e s ta f f w il l p re p a re th is s u p p le m e n t s e p a ra te ly f ro m th is S E R.
1.4 In te rim St af f Gu id anceT he l i cens e r enewal pr ogr am i s a l i v i ng pr ogr am. T he s t af f , i ndus t r y , and ot her i nt er est ed st akeh ol der s ga i n ex per i ence and de v el op l ess ons l ear ned wi t h eac h r enewed l i cens e. T he l ess ons l ear ned add r ess t he s t af f's pe r f or m ance goal s of saf et y and s ecur i t y; openne ss i n t he re g u la to ry p ro c e s s; e f f e c tiv e n e s s , e f f ic ie n c y, re a li s tic , a n d tim e ly a c tio n; a n d e x c e ll e n c e in a g e n c y m a n a g e m e n t. In te r im s ta f f g u id a n c e (I S G) is d o c u m e n te d f o r u s e b y th e s ta f f , in d u s tr y, and ot her i nt er est ed st akeh ol der s unt i l i t i s i ncor por at ed i nt o such l i cense r ene wa l gui dan ce d o c u m e n ts a s th e S R P-L R a n d th e G A L L R e p o rt.T h e f o ll o w in g ta b le p ro v id e s th e c u rre n t IS G , is s u e d b y th e s ta f f , a s w e ll a s th e S E R s e c tio n s in whi ch t he s t af f addr ess es e ach I SG i ss ue.
1-7 IS G Is sue (A ppr ov ed IS G N o.)Pu rp oseSE R Sec tio n Nicke l-al loy compo nent s in the rea ctor pr essur e bo undar y (LR-ISG-19B)
Cr acking of nickel-alloy compo nent s in t he r eacto r p ressu re bound ary. IS G und er dev elopme nt. N EI and EP RI-M RP w ill d ev elop an augmen ted inspect ion pro gra m fo r G ALL A M P X I.M 11-B. T his A M P w ill not be com ple ted un til the NRC appr ov es an aug mente d in specti on pro gra m fo r n ickel-alloy base met al compone nts and w elds as pr oposed by E PR I-M RP. N/A (P W Rs on l y)Co rr osion of dry w ell shell in M ark I conta inment s (LR-IS G-20 06-01)T o ad dre ss conce rns rela ted to corr osion of dry w ell shell in M ark I conta inment s.3.0.3.2.27 3.0.3.2.23 3.5 4.7.2 1.5 Sum mar y o f Op en It emsA s a re s u l t o f i t s re vi e w o f t h e L R A , i n c l u d i n g a d d i t i o n a l i n fo rm a t i o n s u b m i t t e d t o t h e s t a ff t hr ough J ul y 10, 2006, t he s t af f i dent i f i ed t he f ol l owi ng open i t em s (O I s), whi ch r em ai ned ope n when t he SE R wi t h open i t em s was i ss ued i n August 2006. An i ss ue i s c onsi der ed open i f t he ap pl i c an t ha s no t pr es en t ed s uf f i c i en t i nf or m at i on or i f t he s t af f ha s no t c ompl et ed i t s r ev i ew.Each O I has been a ss i gned a uni que i dent i f y i ng num ber. By l et t er s da t ed Apr i l 7, Jun e 20, D ecem ber 3, and D ecem ber 15, 200 6, and Fe br uar y 15, 200 7, t he a ppl i cant r espo nde d t o t hose O I s. T he s t af f r ev i ewed t hese r espo nses and c l osed eac h of t he O I s. T he bas i s f or cl osi ng t he O I s i s as f ol l ow s: O I 4.7.2-1.1: (Sect i on 4.7.2 - D r y wel l C or r osi on)I n R AI 4.7.2-1 dat ed Mar ch 1 0, 2006, t he s t af f r eques t ed t hat t he appl i cant pr ov i de t he f ol l owi ng i nf or m at i on: For t he dr y wel l cor r osi on dur i ng t he l at e 1980s and t he new c or r osi on f ound du r i ng t he s ubse quent i nspe ct i ons, pr ov i de t he pr oces s us ed t o es t abl i sh c onf i denc e t hat t he s am pl i ng done t o i dent i f y t he ar eas of cor r osi on has been a dequat e.I n i t s r espo nse d at ed A pr i l 7, 200 6, t he a ppl i cant em pha si z ed t hat i t em pl oy s a r obu st pr ocess t o es t abl i sh c onf i denc e t hat t he nat ur e and l ocat i ons of sam pl i ng done and ar eas cons i der ed f or i dent i f y i ng t he ar eas of cor r osi on hav e been adequa t e. T he appl i cant st at ed t hat t he el em ent s of p ro c e s s h a d b e e n d e v e lo p e d o v e r s e v e ra l y e a rs a n d d e f in e d in s e v e ra l te c h n ic a l d o c u m e n ts subm i t t ed t o t he NR C i n t he 1990 s. I n addi t i on, t he appl i cant st at ed t hat O C G S has co nduc t ed ex t ensi v e ex am i nat i ons t o i dent i f y t he c ause of dr y wel l cor r osi on, em pl oy ed a r obus t sam pl i ng p ro c e s s , q u a n tifie d w ith re a s o n a b le a s s u ra n c e th e e x te n t o f d ryw e ll s h e ll th in n in g d u e to c o r r o s io n , a n d a s s e s s e d its im p a c t o n th e d r yw e ll's s tr u c tu r a l in te g r ity.Th e s t a f f's r e v i e w o f t h e a p p l i c a n t's r e s p o n s e d e t e r mi n e d t h a t t h e r e h a d b e e n n o UT m easu r em ent s t aken i n t he l ower por t i on of t he s pher i cal ar ea abov e t he s and-pock et ar ea. T he s ta f f re q u e s te d th a t th e a p p li c a n t c la rif y i ts U T s a m p li n g p la n f o r th e e n tire d ryw e ll s h e ll a s s e s s m e n t.
1-8 I n i t s s uppl em ent al r espo nse dat ed J une 20, 2006, t he appl i cant st at ed:A r ev i ew of t he dr y wel l f abr i cat i on and i nst al l at i on det ai l s s how t hat t he wel ds t hat at t ach t he 0.770 i nche s (t he co r r ect t hi ckness i s 0.770 i nche s, not 0.722 i nch as i ndi cat ed i n t he m eet i ng not es) nom i nal pl at es t o t he 1.154 i nch nom i nal pl at es a t el ev at i on 23 f t 6 7/8 i nch ar e doubl e bev el f ul l penet r at i on wel ds. T he ex t er nal edge o f t he 1.154 i nche s pl at es i s t aper ed t o 3 t o 12 m i ni m um as r equi r ed by AS M E S ect i on VI I I , Subsec t i on UW-35, whi l e t he i nt er nal edge o f t he 1.154 i nch pl at es a r e f l ush wi t h t he 0.770 i nch pl at es. T hus t her e ar e no l edges t hat cou l d r et ai n wat er l eaka ge and r esul t i n m or e se v er e co r r osi on t han i n ar eas i ncl uded i n t he i nspe ct i on pr ogr am. Al so, t hi s j oi nt i s l ocat ed bel ow t he equa t or i al cent er of t he s pher e. T her ef or e, i n t he ev ent t hat wat er m ay r un down t he gap b e tw e e n th e d ryw e ll s h e ll a n d th e c o n c re te w a ll it w o u ld n o t c o ll e c t o n th is jo in t.In 1 9 9 1 , O ys te r C re e k p e rf o rm e d ra n d o m in s p e c tio n s o f th e d ryw e ll s h e ll.U l t r ason i c t est i ng i nspe ct i ons wer e co nduc t ed at 19 l ocat i ons on ei t her t he 1.154 i n c h th i c k p l a te s o r o n th e 0.7 7 0 i n c h th i c k p l a te s. T h e U T m e a s u re m e n ts w e re t aken on a 6 i nch x 6 i nch gr i d (49 UT s) at eac h l ocat i on. T he UT m easu r em ent r esul t s s how t hat t hi nni ng of t he pl at es a t t hese l ocat i ons i s l ess sev er e t han t he ar eas t hat ar e i ncl uded i n t he c or r osi on-m oni t or i ng pr ogr am. For t hi s r easo n, t he t r ansi t i on ar ea was not added t o t he c or r osi on-m oni t or i ng pr ogr am. Based on t he abov e, Am er G en c oncl udes t hat ar eas m oni t or ed unde r t he dr y wel l cor r osi on m oni t or i ng p r ogr am bou nd t he t r ansi t i on (f r om 1.154 i nche s t o 0.770 i nch t hi ck pl at es) ar ea of t he dr y wel l she l l. N ev er t hel ess , U T m easu r em ent s wi l l be t aken on t he 0.770 i nch t hi ck pl at e, j ust abov e t he wel d, pr i or t o ent er i ng t he per i od of e x te n d e d o p e ra tio n. T he m easu r em ent s wi l l be co ndu ct ed a t one l ocat i on u si ng t he 6 i nch x 6 i nch gr i d. A secon d se t of U T m easu r em ent s wi l l be t aken t wo r ef uel i ng out ages l at er at t he s am e l ocat i on. T he r esul t s of t he m easu r em ent s wi l l be ana l y z ed and ev al uat ed t o co nf i r m t hat t he r at e of cor r osi on i n t he t r ansi t i on i s bo unded b y t he ra te o f c o rro s io n o f th e m o n ito re d a re a s in th e u p p e r re g io n o f th e d ryw e ll. If cor r osi on i n t he t r ansi t i on ar ea i s f ound t o be gr eat er t han ar eas m oni t or ed i n t he upper r egi on of t he dr y wel l , U T i nspe ct i ons i n t he t r ansi t i on ar ea wi l l be per f or m ed on t he s am e f r equenc y as t hose per f or m ed on t he uppe r r egi on of t he d ry w e l l (e v e ry o th e r re fu e l i n g o u ta g e).Si m i l ar l y , a r ev i ew of f abr i cat i on and i nst al l at i on det ai l s of t he c ont ai nm ent dr y wel l she l l sho ws t hat t he wel d t hat con nect s t he 2.625" knu ck l e pl at es t o t he 0.640" cy l i nder pl at es a t el ev at i on 71 f t 6 i nch i s a d oubl e bev el f ul l penet r at i on w e ld. T h e e d g e s o f th e 2.6 2 5 in c h p la te s w e re f a b ric a te d w ith a 3 to 1 2 ta p e r to pr ov i de a s m oot h t r ansi t i on f r om t he t hi ck er t o t he t hi nner pl at e as r equi r ed by A S M E S e c tio n V III, S u b s e c tio n U E-3 5. T h u s th e re a re n o le d g e s th a t c o u ld re ta in wat er l eaka ge and r esul t i n m or e se v er e co r r osi on t han t he ar eas i ncl uded i n t he i n s p e c t i o n p r o g r a m.In 1 9 9 1 , O ys te r C re e k p e rf o rm e d ra n d o m in s p e c tio n s o f th e d ryw e ll s h e ll.U l t r ason i c t est i ng (U T) i nspe ct i ons wer e co nduc t ed at 18 l ocat i ons on t he 2.625 1-9 i nch t hi ck knu ck l e pl at e and a t f our (4) l ocat i ons on t he 0.640 i nch t hi ck cy l i nder pl at e. T he UT m easu r em ent s wer e t aken on a 6 i nch x 6 i nch gr i d (49 UT s) at each l ocat i on. T he UT m easu r em ent r esul t s s howed t hat t hi nni ng of t he pl at es a t t hese l ocat i ons was l ess sev er e t han t he ar eas t hat ar e i ncl uded i n t he c or r osi on m oni t or i ng pr ogr am. For t hi s r easo n t he k nuck l e ar ea was not added t o t he cor r osi on m oni t or i ng pr ogr am. Based on t he abov e, Am er G en c oncl udes t hat ar eas m oni t or ed unde r t he dr y wel l cor r osi on m oni t or i ng pr ogr am bound t he knuc kl e ar ea of t he dr y wel l she l l. H owev er , U T m easu r em ent s wi l l be t aken abov e t he 2.625 i nch knuc kl e pl at e i n t he 0.640 i nch t hi ck pl at e pr i or t o ent er i ng th e p e rio d o f e x te n d e d o p e ra tio n. T he s t af f bel i ev es t hat r andom sam pl i ng of U T m easu r em ent i s v al uabl e i f t he l i kel i hood of cor r osi on i s al m ost equal at ev er y pl ace i n t he r egi on c onsi der ed f or U T m easu r em ent s. I f t he g e o m e t r y o f t h e r e g i o n a n d w a t e r fl o w i n t h e a i r g a p s u g g e s t t h a t o n e a r e a i s m o r e l i k e l y t o h a ve c o r r o s i o n t h a n a n o t h e r t h e n t h e s a m p l i n g p l a n m u s t c o n s i d e r a r e a s m o r e l i k e l y t o h a ve cor r osi on i n addi t i on t o t he r andom l y sel ect ed ar eas. I f t he wat er f l ow i n t he ai r gap i s hi gh, t he appl i cant's ar gum ent t hat t he wel d t r ansi t i on wi l l not al l ow wat er acc um ul at i on woul d be acc ur at e. H owev er , i f t he wat er f l ow i s s l ow, t he appl i cant's ar gum ent m ay not hol d t r ue. D ur i ng t he f or t hcom i ng out age, t he appl i cant pl ans U T m easu r em ent s at one l ocat i on on e ach of t he t r ansi t i on ar eas. T he s t af f bel i ev es t hat m easu r em ent at f our l ocat i ons i n eac h t r ansi t i on ar ea woul d be m or e co nser v at i v e. T he l ocat i ons al ong t he t hi ck ness t r ansi t i on s houl d be c onsi st ent w ith th e a re a s th a t h a v e la rg e w a te r a c c u m u la tio n a n d c o rro s io n in th e s a n d b e d re g io n. T h is i t em was i dent i f i ed as O pen I t em 4.7.2-1.1 i n t he SE R wi t h O pen I t em s i ss ued i n August 2006.T he appl i cant updat ed t he I W E P r ogr am C om m i t m ent s i n i t s Decem ber 3, 2006, sub m i ss i on (pages 73 and 74, i t em s 10 and 11) wi t h f our sep ar at e se t s of U T t hi ck ness m easu r em ent s of th e d ryw e ll s h e ll a t tw o a re a s o f tra n s iti o n b e tw e e n s h e ll p la te th ic k n e s s e s u s in g a 6"x 6" g rid (i.e., f o u r s e p a r a t e 4 9-p o i n t UT s e t s a t t h e t r a n s i t i o n a t e l e v a t i o n 2 3' 6 7/8" a n d f o u r s e t s o f UTs at el ev at i on 71'-6"). T he s peci f i c l ocat i ons sel ect ed wi l l be bas ed on p r ev i ous oper at i onal ex per i ence (i.e., bi ased t owar d ar eas t hat hav e ex per i ence d co r r osi on or ex posu r e t o wat er l eaka ge). T hese m easu r em ent s wi l l be at t he s am e l ocat i ons pr i or t o t he per i od of ex t ended ope r at i on a nd a t t he se cond r ef uel i ng o ut age af t er t he i ni t i al i nspe ct i on. I f cor r osi on i n t hese t r ansi t i on ar eas i s gr eat er t han i n ar eas m oni t or ed i n t he uppe r dr y wel l , U T i nspe ct i ons i n t he t r ansi t i on ar eas wi l l be on t he s am e f r equenc y as t hose i n t he uppe r dr y wel l (ev er y ot her r ef uel i ng o ut age). O f t hese f our l ocat i ons, t her e w er e U T m easu r em ent s at t wo f or each t r ansi t i on ar ea dur i ng 2006 out age. T hese f i r st-t i m e r eadi ngs show t hat t he m ean and i ndi v i dual th ic k n e s s e s m e e t a c c e p ta n c e c rite ria w ith a d e q u a te m a rg in. T h e re w il l b e U T m e a s u re m e n ts in t he r em ai ni ng t wo l ocat i ons at eac h t r ansi t i on ar ea dur i ng t he nex t out age pr i or t o t he per i od of ex t ended o per at i on.T h e s ta f f f in d s th a t th e a p p li c a n t's a c tio n s to in c lu d e in th e p ro g ra m U T m e a s u re m e n t o f s h e ll ar eas t hat m ay ex per i ence i ncr ease d r at es o f cor r osi on r esol v es t he s t af f con cer n. T he bas i s f or th i s fin d i n g i s th a t t h e U T m e a s u re m e n ts s h o u l d p ro v i d e a n a d e q u a te d a ta b a s e to c o n firm whet her t he r andom sam pl i ng pr ogr am f or U T m easu r em ent s i s r easo nabl y r epr esen t at i v e.T he s t af f , howev er , not ed an i ncon si st ency i n t he l i cens e r enewal com m i t m ent l i st (pages 45 and 46, com m i t m ent num ber 27, "AS M E S ect i on XI , Subsec t i on I W E," i t em num ber s 10 and 11) wher e i t st at es t hat t he UT m easu r em ent s wi l l be at one l ocat i on. I n a l et t er dat ed 1-10 D ecem ber 15, 2006, t he appl i cant not ed t he edi t or i al er r or i n i t s l et t er dat ed Decem ber 3, 2006.Th e a p p l i c a n t c o r r e c t e d t h e e r r o r b y c h a n g i n g c o mmi t me n t 2 7 i t e m n u mb e r s 1 0 a n d 1 1 f r o m UT m e a s u re m e n ts a t o n e lo c a tio n to U T m e a s u re m e n ts a t fo u r lo c a tio n s. O p e n Ite m O I 4.7.2-1.1 is cl osed.I n i t s l et t er dat ed Febr uar y 15, 2007, t he appl i cant r ev i sed a co m m i t m ent (C om m i t m ent N o. 27)by addi ng I t em 21, whi ch s t at es t hat t he per f or m ance of t he f ul l sc ope of dr y wel l san d bed re g io n in s p e c tio n s w il l b e c o n d u c te d e v e ry o th e r re f u e li n g o u ta g e. T h e s ta f f id e n tifie d th is com m i t m ent i t em as a l i cens e co ndi t i on.O I 4.7.2-1.2: (Sect i on 4.7.2 - D r y wel l C or r osi on)I n R AI 4.7.2-1 dat ed Mar ch 1 0, 2006, t he s t af f r eques t ed t hat t he appl i cant pr ov i de t he f ol l owi ng i nf or m at i on: For t he dr y wel l cor r osi on dur i ng t he l at e 1980s and t he new c or r osi on f ound du r i ng t he s ubse quent i nspe ct i ons, pr ov i de t he pr oces s us ed t o es t abl i sh c onf i denc e t hat t he s am pl i ng done t o i dent i f y t he ar eas of cor r osi on has been a dequat e.T h e s ta f f's re v ie w o f th e A p ril 7 , 2 0 0 6 , re s p o n s e d e te rm in e d th a t th e m o s t s u s c e p tib le b a ys in th e s a n d p o c k e t re g io n o f th e d ryw e ll s h e ll h a d b e e n in c o rp o ra te d in th e s a m p li n g. H o w e v e r, it was no t cl ear t o t he s t af f whet her t he j unct i on at el ev at i on 6' 10.25" had be en r epr esen t ed i n t he s a m p li n g. T o d e te rm in e w h e th e r th e re a d in g s a re ta k e n a t th e v u ln e ra b le lo c a tio n s a n d re li a b le t echn i ques ar e us ed, t he s t af f r eques t ed t hat t he appl i cant ex pl ai n why t hi s ar ea s houl d not be in c lu d e d in th e s a m p li n g p la n. I n i t s r espo nse dat ed J une 20, 2006, t he appl i cant not ed t hat t he dr y wel l con st r uct i on and f a b ric a tio n d e ta il s s h o w th a t th e p re s e n c e o f th e d ryw e ll s k irt p re v e n ts m o is tu re in tru s io n in to th e p la te. T h e a p p li c a n t a ls o n o te d th a t A m e rG e n h a s e x te n s iv e ly in v e s tig a te d d ryw e ll cor r osi on, i ncl udi ng t he e m bed ded shel l. P l ant-speci f i c and i ndu st r y ope r at i ng e x per i ence in d ic a te th a t c o rro s io n o f th e e m b e d d e d s te e l i n c o n c re te is n o t s ig n ific a n t b e c a u s e th e s h e ll is pr ot ect ed by t he hi gh al kal i ni t y of con cr et e. C or r osi on c oul d bec om e si gni f i cant onl y i f t he conc r et e env i r onm ent i s ag gr ess i v e. T he appl i cant al so s t at ed t hat hi st or i cal dat a sh ow t hat t he env i r onm ent i n t he s and bed r egi on i s no t aggr ess i v e, and t hus any wat er i n co nt act wi t h t he em bedded she l l i s no t aggr ess i v e. T he dat a sh ow t hat cor r osi on of t he dr y wel l she l l i n t he s and bed r egi on i s ga l v ani c an d i m pur i t i es l i ke c hl or i des and s ul f at es a r e not f undam ent al l y i nv ol v ed i n t he anod i c an d ca t hodi c c or r osi on r eact i ons. T hus, onl y l i m i t ed c or r osi on i s an t i ci pat ed f or t he d ryw e ll e m b e d d e d s h e ll.T h e a p p li c a n t c o n c lu d e d th a t c o rro s io n m o n ito rin g o f th e s a n d b e d re g io n o f th e d ryw e ll s h e ll is b o u n d in g w ith re s p e c t to c o rro s io n th a t m a y h a v e o c c u rre d o n th e d ryw e ll e m b e d d e d s h e ll bef or e 1992. Af t er 1992, cor r osi on of t he em bedded she l l has not been s i gni f i cant bec ause of t h e mi t i g a t i v e mea s u r e s i m p l e m e n t e d a n d t h e r o b u s t d r y w e l l c o r r o s i o n AMP.T he s t af f under st ands t he appl i cant's t echn i cal bas i s t o su ppor t t he appl i cant's v i ew t hat t he i nacc ess i bl e por t i on of t he dr y wel l she l l (i.e., em bedded bet ween t he c oncr et e f l oor i nsi de, and conc r et e out si de) i s no t l i kel y t o be s ubj ect t o t he s am e t y pe of sev er e co r r osi on as ex per i ence d in th e s a n d b e d a re a. H o w e v e r, th e g e n e ra l c o rro s io n in th e li n e r p la te s e m b e d d e d in c o n c re te o f a n u m b e r o f p re s s u rize d w a te r re a c to r (P W R) a n d B W R c o n ta in m e n ts s u g g e s ts th a t c e rta in i r r egul ar i t i es d ur i ng t he c onst r uct i on (i.e. f or ei gn obj ect s or v oi ds i n t he c oncr et e) cou l d t r i gger cor r osi on not ar r est ed by t he c oncr et e env i r onm ent. T hi s s ugges t i on i s pa r t i cul ar l y si gni f i cant f or 1-11 th e p la te s p o te n tia ll y s u b je c t to w a te r s e e p a g e. T h e a p p li c a n t's p o s iti o n th a t th e u n ifo rm ly r e d u c e d t h i c k n e s s u s e d i n t h e G E a n a l y s i s c o m p e n s a t e s for a n y c o r r o s i o n t h a t m a y h a ve occ ur r ed bef or e t he ar ea was sea l ed i n 1992 has som e v al i di t y. T hi s i t em was I dent i f i ed as O pen I t em O I 4.7.2-1.2 i n t he SE R wi t h O pen I t em s i ss ued i n August 2006.D u rin g th e O c to b e r 2 0 0 6 re f u e li n g o u ta g e , th e a p p li c a n t in s p e c te d th e e m b e d d e d d ryw e ll s h e ll i n t he t r ench es i n bay s #5 and 17 af t er r em ov i ng t he f i l l er m at er i al i n t he t r ench es. T he appl i cant o b s e rv e d a p p ro x im a te ly 5 in c h e s o f s ta n d in g w a te r in th e tre n c h in b a y #5 , a n d th e tre n c h in bay #17 was dam p. Appl i cant i nv est i gat i ons conc l uded t hat t he l i kel y wat er sou r ces wer e a det er i or at ed dr ai npi pe c onnec t i on and a v oi d i n t he bot t om of t he Sub-Pi l e R oom dr ai nage t r ough or con dens at i on wi t hi n t he dr y wel l t hat ei t her f el l or washe d down t he i nsi de of t he dr y wel l she l l t o t he c oncr et e f l oor. W at er sam pl es f r om t he t r ench i n bay #5 wer e t est ed and det er m i ned t o be no n-aggr ess i v e i n pH (8.4 - 10.21), chl or i des (13.6 - 14.6 ppm), and s ul f at es (2 2 8 - 2 3 0 p p m).T h e a p p l i c a n t e n t e r e d t h e c o n d i t i o n i n t o t h e c o r r e c t i ve a c t i o n p r o c e s s. S e ve r a l c o r r e c t i ve act i ons i ncl uded r epai r of t he t r ough c oncr et e i n t he ar ea unde r t he r eact or v ess el t o pr ev ent wat er f r om m i gr at i ng t hr ough t he c oncr et e and r each i ng t he dr y wel l she l l and c aul ki ng of t he i nt er f ace b et we en t he d r y we l l shel l and t he d r y we l l concr et e f l oor/cur b i ncl udi ng t he t r ench ar eas. T he t r ench bay i n bay #5 al so was ex cav at ed t o unc ov er an add i t i onal 6 i nche s of t he i n t e r n a l d r y w e l l s h e l l s u r f a c e f o r i n s p e c t i o n a n d UT t h i c k n e s s me a s u r e me n t. A t o t a l o f 5 8 4 UT t hi c k ne s s m ea s ur ement s we r e t ak en wi t h a 6"x 6" t empl at e w i t hi n t he t wo t r en c he s. Fo r t y-t wo addi t i onal U T m easu r em ent s wer e t aken i n t he newl y ex pose d ar ea i n bay #5.V is u a l e x a m in a tio n o f th e d ryw e ll s h e ll w ith in th e tw o tre n c h e s d e te c te d m in o r s u rf a c e ru s t w ith no r ecor dabl e co r r osi on on t he s hel l i nner sur f ace. T he UT m easu r em ent s i ndi cat ed t hat t he dr y we l l shel l i n t he t r ench ar eas h ad e x per i ence d a 0.038" r edu ct i on i n aver age t hi ckness si nce 198 6. A m er gen concl ude d t hat t he w al l t hi nni ng w as a r esul t of cor r osi on o n t he e x t er i or sur f ace o f th e d ryw e ll s h e ll in th e s a n d b e d re g io n b e tw e e n 1 9 8 6 a n d 1 9 9 2 w h e n th e s a n d w a s s til l i n pl ace and t he c or r osi on was kno wn.An engi neer i ng ev al uat i on t o det er m i ne t he i m pact of t he as-f ound wat er on t he c ont i nued i nt egr i t y of t he dr y wel l con cl uded t hat t he m easu r ed wat er che m i st r y v al ues and t he l ack of any i n d i c a t i o n s o f r e b a r d e g r a d a t i o n o r c o n c r e t e s u r fac e s p a l l i n g s u g g e s t t h a t t h e p r o t e c t i ve p a s s i ve f il m e s ta b li s h e d d u rin g c o n c re te in s ta ll a tio n a t th e e m b e d d e d s te e l/c o n c re te in te rf a c e is s til l i nt act and t hat si gni f i cant cor r osi on of t he dr y wel l she l l i s no t ex pect ed as l ong as t hi s be ni gn env i r onm ent i s m ai nt ai ned. Mor e sp eci f i cal l y , t hi s en gi neer i ng ev al uat i on i ndi cat es t hat no si gni f i cant cor r osi on of t he i nner sur f ace of t he em bedded dr y wel l she l l i s an t i ci pat ed f or t he f ol l ow i ng r easo ns:
- T he wat er i n co nt act wi t h t he dr y wel l she l l has been i n co nt act wi t h t he adj acen t c o n c re te , w h ic h is a lk a li n e , in c re a s e s th e p H o f th e w a te r, a n d in h ib its c o rro s io n. T h is hi gh-pH wat er con t ai ns l ev el s of i m pur i t i es s i gni f i cant l y bel ow t he El ect r i c Power R esea r ch I nst i t ut e (E P R I) em bed ded st eel gui del i nes a ct i on l evel r ecom m end at i ons.
- A n y n e w w a te r (e.g., r eact or coo l ant) ent er i ng t he c oncr et e-t o-shel l i nt er f ace (now m in im ize d b y re p a irs) a ls o in c re a s e s p H b y i ts m ig ra tio n th ro u g h a n d c o n ta c t w ith c o n c re te , c re a tin g a n o n-a g g re s s iv e , a lk a li n e e n v iro n m e n t.
1-12
- M in im a l c o rro s io n o f th e w e tte d in n e r d ryw e ll s te e l s u rf a c e in c o n ta c t w ith c o n c re te is ex pect ed onl y dur i ng out ages bec ause t he dr y wel l i s i ner t ed wi t h ni t r ogen du r i ng oper at i ons. Ev en dur i ng out ages , she l l cor r osi on l oss es a r e ex pect ed t o be i nsi gni f i cant as t he ex posu r e t i m e t o ox y gen i s v er y l i m i t ed and t he wat er pH i s ex pect ed t o be re l a ti v e l y h i g h. A l s o re p a i rs/m o d i fic a ti o n s d u ri n g th e 2 0 0 6 o u ta g e w i l l fu rth e r m i n i m i ze ex posu r e of t he dr y wel l she l l t o ox y gen.Af t er t he UT t hi ck ness m easu r em ent s du r i ng t he 2006 out age of t he newl y-ex pose d sh el l ar ea in b a y #5 , w h ic h h a d n o t b e e n e x a m in e d s in c e in iti a l c o n s tru c tio n , a re d u c tio n o f a v e ra g e s h e ll t hi ck ness of 0.041" was o bser v ed. T he appl i cant m ai nt ai ns t hat , al t hough n o co nt i nui ng cor r osi on i s ex pect ed, t her e i s s uf f i ci ent m ar gi n f or bot h t he 1.154" t hi ck pl at e and t he 0.676"t hi ck pl at e ev en as sum i ng t he s am e r educ t i on unt i l t he end of t he per i od of ex t ended o per at i on.T h e a p p li c a n t a ls o h a s e n h a n c e d th e A M P to re q u ire p e rio d ic in s p e c tio n o f th e d ryw e ll s h e ll subj ect t o con cr et e (wi t h w at er) envi r onm ent s i n t he i nt er nal em bed ded shel l ar ea. A f t er each i n s p e c t i o n , UT t h i c k n e s s me a s u r e me n t s w i l l b e e v a l u a t e d a n d c o mp a r e d t o p r e v i o u s UT t hi ck ness m easu r em ent s. I f r esul t s ar e uns at i sf act or y addi t i onal cor r ect i v e ac t i ons, as nece ss ar y , wi l l m ai nt ai n dr y wel l she l l i nt egr i t y t hr oughou t t he per i od of ex t ended o per at i on.T o in v e s tig a te th e f e a s ib il ity o f s ta te-o f-th e-a rt n o n-d e s tru c tiv e e x a m in a tio n te c h n iq u e s to d e te rm in e th e c o n d iti o n o f th e e m b e d d e d re g io n , th e a p p li c a n t c o n ta c te d E P R I a n d o th e r u til ity owner s t hat use t hese t echn i ques. Af t er di sc uss i ons and f i ndi ngs, t he appl i cant under st ood t hat a "gui ded wav e" t echn ol ogy m ay be abl e t o pr ov i de s om e qual i t at i v e i nf or m at i on on whe t her t he embed de d s he l l ha s un de r go ne c or r os i on; ho we v er , ne i t he r t hi s no r an y ot he r k no wn non-dest r uct i v e m et hods cou l d det er m i ne t he t hi ck ness of t he em bedded dr y wel l she l l or t he spec i f i c ex t ent of cor r osi on.Based on r ev i ew of t he appl i cant's ev al uat i on of t he c ondi t i on of t he i nacc ess i bl e por t i on of dr y wel l she l l em bedded i n co ncr et e, t he appl i cant's ac t i ons t o dat e, and t he enha nced i nspe ct i on pr ogr am i ncl udi ng a de t ai l ed UT m easu r em ent pl an t o whi ch t he appl i cant c o m m itte d , th e s ta f f c o n c lu d e s w ith re a s o n a b le a s s u ra n c e th a t th e e n v iro n m e n t in th e re g io n is s u ff i c i e n tl y n o n-a g g re s s i v e fo r n o s i g n i fic a n t p ro g re s s i v e c o rro s i o n. T h e re fo re , t h e s ta ff c o n c e rn i s r esol v ed and O pen I t em 4.7.2-1.2 i s c l osed.I n i t s l et t er dat ed Febr uar y 15, 2007, t he appl i cant cha nge a c om m i t m ent (C om m i t m ent N o. 27)by addi ng I t em 20, whi ch s t at es Am er G en i s c om m i t t ed t o per f or m v i sual and UT i nspe ct i ons of t he dr y wel l she l l i n t he i nspe ct i on t r ench es i n dr y wel l bay s #5 and #1 7. Am er G en wi l l m oni t or th e tw o tre n c h e s f o r th e p re s e n c e o f w a te r d u rin g e a c h re f u e li n g o u ta g e. T h e s ta f f id e n tifie d th is com m i t m ent i t em as a l i cens e co ndi t i on.
1-13 O I 4.7.2-1.3: (Sect i on 4.7.2 - D r y wel l C or r osi on)I n R AI 4.7.2-1 dat ed Mar ch 1 0, 2006, t he s t af f r eques t ed t hat t he appl i cant pr ov i de t he f ol l owi ng in f o rm a tio n: A s u m m a ry o f th e f a c to rs c o n s id e re d in e s ta b li s h in g th e m in im u m re q u ire d d ryw e ll t hi ckness.In its re s p o n s e d a te d A p ril 7 , 2 0 0 6 , th e a p p li c a n t e x p la in e d th a t th e f a c to rs c o n s id e re d in e s ta b l i s h i n g th e m i n i m u m re q u i re d d ry w e l l th i c k n e s s a t va ri o u s e l e v a ti o n s o f th e d ry w e l l a re desc r i bed i n det ai l i n engi neer i ng anal y ses doc um ent ed i n t wo G E r epor t s, I ndex N os. 9-1, 9-2, a n d 9-3 , 9-4. I n t he appl i cant's di sc uss i on, a su m m ar y of t he m et hods and as sum pt i ons used i n t he buc kl i ng anal y si s of t he s hel l i n t he s and-pock et ar ea has been g i v en. Al t hough t he NR C has not appr ov ed AS M E C ode Case N-284 f or use on a ge ner i c ba si s, t he s t af f does not t ake ex cept i on t o t he us e of av er age c om pr ess i v e st r ess acr oss t he m et al t hi ck ness f or buc kl i ng anal y si s of t he as-bui l t she l l. H owev er , i f t he c or r osi on has r educ ed t he s t r engt h of t he r em ai ni ng m et al t hr ough th e c ro s s s e c tio n , th is u s e m a y n o t b e v a li d. T h e s ta f f re q u e s te d th a t th e a p p li c a n t a d d re s s th is i ss ue.I n i t s r espo nse dat ed J une 20, 2006, t he appl i cant di sc uss ed i t s us e of AS M E C ode C ase N-284:A l th o u g h R e v i s i o n 1 o f C o d e C a s e 2 8 4 h a d n o t y e t b e e n i s s u e d w h e n th e re p o rt (An A SM E S ect i on VI I I Ev al uat i on of O y st er C r eek D r y wel l f or W i t hout Sand Cas e, Par t I I - St ab i l i t y Ana l y s i s ," G E Repo r t , I nd ex No. 9-4, Rev i s i on 0, DR F #00664) was wr i t t en, t he aut hor s c onsu l t ed wi t h t he pr i m ar y aut hor of t he r ev i si on.Based on t hose di sc uss i on, t he pl ast i ci t y cor r ect i on f act or s us ed i n t he ev al uat i on a re th e s a m e a s th o s e in F ig u re 1 6 1 0-1 o f C o d e C a s e N-2 8 4 R e v is io n 1. T he appl i cant st at ed t hat t he t echn i cal appr oach use d i n t he s t abi l i t y ev al uat i on of R ef er ence 2 i s en t i r el y con si st ent wi t h t he gui del i nes i n AS M E C ode Case N-284, R ev i si on 1. I n addi t i on, t he app l i cant concl ude d t hat t he co r r osi on o n t he o ut si de su r f ace o f t he sh el l wi l l not i nt r odu ce ecc ent r i ci t i es t hat woul d si gni f i cant l y i m pact t he "e/t" v al ue of 1.0 as sum ed i n AS M E C ode C a s e N-2 8 4. T h e a p p li c a n t a ls o s ta te d th a t it e x p e c te d a d d iti o n a l e c c e n tric ity f ro m s h e ll cor r osi on i n ser v i ce t o be accom m oda t ed w i t hi n t he a l l ow abl e l i m i t f or i m per f ect i ons.T he s t af f bel i ev ed t hat t he appl i cant pr ov i ded a t hor ough ex pl anat i on of t he f act or s c onsi der ed i n appl y i ng t he AS M E C ode Case N-284-1 f or buc kl i ng anal y si s of t he c or r oded s hel l i n t he s a n d b e d a re a o f th e d ryw e ll s h e ll. H o w e v e r, th e a p p li c a n t d id n o t a d d re s s w h e th e r it is appr opr i at e t o as sum e t he s am e st r engt h ac r oss t he c or r oded s ect i on of t he s hel l. T he i ncor por at i on of t he "e/t" cor r osi on c once pt wi t h a r epr esen t at i v e di st r i but i on of st r engt h al ong t he c or r oded s ect i on t hat r ecog ni z e t he l ower st r engt h at t he c or r oded s i de and f ul l st r engt h at t he i nsi de s ur f ace, cou l d su ppor t t he c l ai m of con ser v at i sm i n t he anal y si s. T hi s i t em was i dent i f i ed as O pen I t em O I 4.7.2-1.3 i n t he SE R wi t h O pen I t em s i ss ued i n August 2006.O n f u rth e r e v a lu a tio n o f th e a p p li c a n t's in f o rm a tio n , th e s ta f f c o n c lu d e s th a t th e s ta b il ity e v a l u a ti o n w a s c o n s i s te n t w i th th e g u i d e l i n e s o f A S M E C o d e C a s e N-2 8 4-1. T h e s ta ff's c o n c e rn about use of t he s am e se ct i on s t r engt h ac r oss t he c or r oded s ect i on of t he s hel l i s ad dr ess ed by C o d e C a s e N-2 8 4-1 , w h ic h u s e s c o n s e rv a tiv e a s s u m p tio n s to d e te rm in e s h e ll c a p a c ity 1-14 r edu ct i on f act or s (i.e., a s s u m p tio n o f im p e rf e c tio n li m it i n d ic a te d b y p a ra m e te r "e/t" to b e 1.0 in t he c ode c ase) ex pect ed t o co m pens at e r easo nabl y f or suc h us e of t he s am e se ct i on s t r engt h.In a d d i ti o n , t h e a p p l i c a n t c o n s e rv a ti v e l y a s s u m e d th e l o c a l c o rro d e d th i c k n e s s fo r th e e n ti re dr y wel l she l l r egi on and dem onst r at ed t hat t he c ode-al l owabl e st r ess es wer e sa t i sf i ed cons i st ent l y wi t h t he gui del i nes of t he c ode c ase. T hus, t hi s an al y si s ad ds a m ar gi n of saf et y f or t he dr y wel l st abi l i t y ev al uat i on. O n t hi s ba si s, t he s t af f bel i ev es t hat t he s t abi l i t y ev al uat i on m e th o d is a d e q u a te a n d a c c e p ta b le , a n d th e s ta f f's c o n c e rn is re s o lv e d. O p e n Ite m 4.7.2-1.3 is cl osed.O I 4.7.2-1.4: (Sect i on 4.7.2 - D r y wel l C or r osi on)I n R AI 4.7.2-1 dat ed Mar ch 1 0, 2006, t he s t af f r eques t ed t hat t he appl i cant pr ov i de t he f ol l owi ng in f o rm a tio n: A s u m m a ry o f th e f a c to rs c o n s id e re d in e s ta b li s h in g th e m in im u m re q u ire d d ryw e ll t hi ckness.In its re s p o n s e d a te d A p ril 7 , 2 0 0 6 , th e a p p li c a n t e x p la in e d th a t th e f a c to rs c o n s id e re d in e s ta b l i s h i n g th e m i n i m u m re q u i re d d ry w e l l th i c k n e s s a t va ri o u s e l e v a ti o n s o f th e d ry w e l l a re desc r i bed i n det ai l i n engi neer i ng anal y ses doc um ent ed i n t wo G E r epor t s, I ndex N os. 9-1, 9-2, a n d 9-3 , 9-4. For t he l ocal i z ed t hi n ar eas, t he appl i cant use s t he pr ov i si on of N E-3213.10 of Subsec t i on NE of A S M E C o d e S e c tio n III. T h is p ro v is io n , a lth o u g h n o t d ire c tly a p p li c a b le to th e ra n d o m ly th in ar eas caus ed by cor r osi on, i f use d wi t h ca r e and a dequat e co nser v at i sm , cou l d pr ov i de i n fo rm a t i o n a b o u t t h e p ri m a ry s t re s s l e ve l s a t t h e j u n c t i o n o f t h e t h i n a n d t h i c k a re a s. T h e s t a ff re q u e s te d th a t th e a p p li c a n t p ro v id e a s u m m a ry o f th e p ro c e s s u s e d to a d d re s s th is is s u e. I n i t s r e s p o n s e d a t e d J u n e 2 0 , 2 0 0 6 , t h e a p p l i c a n t n o t e d t h a t " a l t h o u g h p r o v i s i o n s i n ASM E C ode Sect i on I I I , Subsec t i on NE-3213.10 ar e not di r ect l y appl i cabl e t o t he r andom l y t hi n ar eas caus ed by cor r osi on, Am er G en bel i ev es t hat t he pr ov i si ons ar e appl i cabl e t o t he anal y si s of O y st er C r eek dr y wel l she l l bas ed on t he f ol l owi ng:
- T he s t r ess anal y si s of O y st er C r eek dr y wel l pr esen t ed i n R ef er ence 1 sa t i sf i es t he l ocal p ri m a ry s tre s s re q u i re m e n ts o f N E-3 2 1 3.1 0. C o n s e rv a ti s m i n th e a l l o w a b l e p ri m a ry st r ess i nt ensi t y v al ue, t he as sum ed peak pr ess ur e dur i ng t he LO C A condi t i on and t he ass um pt i on of l ocal cor r oded t hi ck ness i n t he ent i r e r egi on of t he dr y wel l pr ov i de addi t i onal st r uct ur al m ar gi n.
- T he Code pr i m ar y st r ess l i m i t s ar e sa t i sf i ed i n t he c or r oded c ondi t i on and t he num ber of f a tig u e c yc le s is s m a ll , th e s u rf a c e d is c o n tin u iti e s f ro m c o rro s io n d o n o t re p re s e n t a si gni f i cant st r uct ur al i nt egr i t y con cer n.
- T he appl i cant i ndi cat ed t hat U T m easu r em ent s of t he dr y wel l she l l abov e t he s and bed r egi on had shown t hat t he m easu r ed gene r al t hi ck ness con t ai ns s i gni f i cant m ar gi n. T he appl i cant st at ed t hat t he ongo i ng c or r osi on i n t hat r egi on i s i nsi gni f i cant and t hat t he m ar gi n cou l d be app l i ed t o of f set unce r t ai nt i es r el at ed t o sur f ace r oug hne ss.
- T he appl i cant st at ed t hat U T m easu r em ent s of t he dr y wel l she l l i n t he s and bed r egi on show t hat t he m easu r ed gene r al t hi ck ness i s gr eat er t han t he 0.736'" t hi ck ness ass um ed in th e b u c k li n g a n a ly s is b y s ig n ific a n t m a rg in s e x c e p t in tw o b a ys , 1 7 a n d 1 9. (R e f e r to 1-15 r es po ns e t o RAI 4.7.2-1(d), Tabl e-2). The mar gi n i n t he ge ne r al t hi c k ne s s of t he t wo bay s i s 0.074" and 0.064" r espe ct i v el y. As si gni f i cant addi t i onal cor r osi on i s no t ex pect ed i n t he s and bed r egi on, t he appl i cant appl i ed t he m ar gi n t o of f set unc er t ai nt i es r el at ed t o t he su r f ace r oug hne ss.Because t he s t af f had no t com pl et ed i t s ev al uat i on, t hi s i t em was i dent i f i ed as O pen I t em O I 4.7.2-1.2 i n t he SE R wi t h O pen I t em s i ss ued i n August 2006.Af t er f ur t her ev al uat i on of t he appl i cant's j ust i f i cat i on, t he s t af f acc ept s t he us e of t he N E-3 2 1 3.1 0 p ro v is io n s o f S u b s e c tio n N E o f A S M E C o d e S e c tio n III. T h e s ta f f a c c e p ta n c e is b a s e d o n th e a p p li c a n t's c o n s e rv a tiv e a p p ro a c h e s to its d e te rm in a tio n o f th e a ll o w a b le s h e ll capa ci t y. Speci f i cal l y , t he appl i cant dem onst r at ed ac cept abl e sh el l cap aci t y bas ed on a cons er v at i v e LO C A peak i nt er nal pr ess ur e (i.e., peak i nt er nal pr ess ur e of 62 ps i i n t he ev al uat i on v er sus t he 44 p si peak i nt er nal pr ess ur e i n an Oy st er C r eek spec i f i c c al cul at i on appr ov ed by t he NR C i n 1993), use of a l ocal cor r oded t hi ck ness f or t he ent i r e r egi on of t he d ryw e ll , a n d c o m p li a n c e w ith lo c a l p rim a ry s tre s s c o d e li m its in th e c o rro d e d c o n d iti o n. In a d d iti o n , th e a p p li c a n t e x p e c ts its e n h a n c e d a c tio n s to p re v e n t s ig n ific a n t a d d iti o n a l c o rro s io n in t he s and bed r egi on. W i t h t hi s i nf or m at i on, t he s t af f's c once r n i s r esol v ed and O pen I t em 4.7.2-1.4 i s c l osed.O I 4.7.2-3: (Sect i on 4.7.2 - D r y wel l C or r osi on)I n R AI 4.7.2-3 dat ed Mar ch 1 0, 2006, t he s t af f not ed t hat l eaka ge f r om t he r ef uel i ng s eal has been i dent i f i ed as one of t he r easo ns f or acc um ul at i on of wat er and c ont am i nat i on of t he sand-pock et ar ea. T he r ef uel i ng wat er pas ses t hr ough t he gap bet ween t he s hi el d co ncr et e and t he dr y wel l she l l i n t he l ong l engt h of i nacc ess i bl e ar eas. As t her e i s a p ot ent i al f or cor r osi on, A S M E C o d e S u b s e c t i o n I W E w o u l d re q u i re a u g m e n t e d i n s p e c t i o n o f t h i s a re a. T h e s t a ff r eques t ed t hat t he appl i cant pr ov i de a s um m ar y of i nspe ct i ons (v i sual and ND E) and m i t i gat i ng act i ons t o pr event wa t er l eaks f r om t he r ef uel i ng se al com pon ent s.I n i t s r espo nse d at ed A pr i l 7, 200 6, t he a ppl i cant st at ed t hat t he r ef uel i ng se al s at O C G S consi st o f s t a i n l e s s s t e e l b e l l o w s. I n t h e mi d-t o-l a t e 1 9 8 0 s , GP U c o n d u c t e d e x t e n s i v e v i s u a l a n d ND E in s p e c tio n s to d e te rm in e th e s o u rc e o f w a te r in tru s io n in to th e s e is m ic g a p b e tw e e n th e d ryw e ll conc r et e sh i el d wal l and t he dr y wel l she l l and ac cum ul at i on i n t he s and bed r egi on. T he i nspe ct i ons conc l uded t hat t he r ef uel i ng bel l ows (seal s) wer e not t he s our ce o f wat er l eaka ge.T he bel l ows wer e r epeat edl y t est ed by hel i um (ex t er nal) and ai r (i nt er nal) wi t h no i ndi cat i on of l eaka ge. Fur t her m or e, any m i nor l eaka ge f r om t he r ef uel i ng bel l ows wou l d be c ol l ect ed i n a c o n c re te tro u g h b e lo w th e b e ll o w s. T h e c o n c re te tro u g h is e q u ip p e d w ith a d ra in li n e th a t w o u ld di r ect any l eaka ge t o t he r eact or bui l di ng equi pm ent dr ai n t ank and pr ev ent i t f r om ent er i ng t he sei sm i c ga p. T he dr ai n l i ne has been c heck ed bef or e r ef uel i ng out ages t o co nf i r m t hat i t i s no t b lo c k e d. T h e o n ly o th e r s e a l i s th e g a s k e t fo r th e re a c to r c a v ity s te e l tro u g h d ra in li n e. T h is gask et was r epl aced af t er t he t est s s howed t hat i t was l eaki ng. H owev er , t he gas ket l eak was r ul ed out as t he pr i m ar y sou r ce o f wat er obs er v ed i n t he s and bed dr ai ns b ecau se t her e i s no c le a r le a k a g e p a th to th e s e is m ic g a p. M in o r g a s k e t le a k s w o u ld b e c o ll e c te d in th e c o n c re te t r ough be l ow t he gas ket and woul d be r em ov ed by t he dr ai n l i ne l i ke l eaks f r om t he r ef uel i ng bel l ow s.I n addi t i on, t he appl i cant not ed t hat addi t i onal v i sual and ND E (dy e penet r ant) i nspe ct i ons on t he r eact or cav i t y st ai nl ess st eel l i ner had i dent i f i ed a s i gni f i cant num ber of cr ack s, som e 1-16 t hr oughwal l. Engi neer i ng anal y si s c oncl uded t hat t he c r ack s wer e m ost pr obabl y cau sed by m e c h a n i c a l i m p a c t o r th e rm a l fa ti g u e , n o t i n te rg ra n u l a r s tre s s c o rro s i o n c ra c k i n g (IG S C C).T hese cr ack s wer e det er m i ned t o be t he s our ce o f r ef uel i ng wat er t hat pas sed t hr ough t he sei sm i c gap. T o pr event l eaka ge t hr oug h t he cr acks, G P U i nst al l ed a n ad hesi v e-t y pe st ai nl ess st eel t ape t o br i dge any obs er v ed l ar ge c r ack s an d su bseq uent l y appl i ed a s t r i ppabl e co at i ng.T hi s r epai r gr eat l y r educ ed l eaka ge and was i m pl em ent ed ev er y r ef uel i ng out age whi l e t he r eact or cav i t y was f l ooded.T he appl i cant not ed t hat O C G S has a l ong-t i m e co m m i t m ent t o m oni t or t he s and bed r egi on dr ai ns f or wat er l eaka ge. A r ev i ew of pl ant doc um ent at i on pr ov i ded no obj ect i v e ev i denc e t hat t he c om m i t m ent had be en i m pl em ent ed s i nce 1998. O C G S I ss ue Repor t N o. 348545 was i ss ued, i n ac cor danc e wi t h t he c or r ect i v e ac t i on pr oces s, t o doc um ent t he l apse i n i m pl em ent i ng t he c om m i t m ent and t o r ei nf or ce s t r i ct com pl i ance wi t h co m m i t m ent i m pl em ent at i on i n t he f ut ur e, i ncl udi ng dur i ng t he per i od of ex t ended o per at i on.T h e a p p li c a n t a ls o c o m m itte d (C o m m itm e n t N o. 2 7) to a u g m e n te d in s p e c tio n s o f th e d ryw e ll in a c c o r d a n c e w i t h A S ME Co d e S e c t i o n X l , S u b s e c t i o n I W E. Th e s e i n s p e c t i o n s c o n s i s t o f UT e xa m i n a t i o n s o f t h e u p p e r r e g i o n o f t h e d r y w e l l a n d vi s u a l e xa m i n a t i o n s o f t h e p r o t e c t i ve c o a tin g o n th e e x te rio r o f th e d ryw e ll s h e ll in th e s a n d b e d re g io n. U T m e a s u re m e n ts w il l supp l em ent t he vi sual i nspe ct i on o f t he co at i ng m easu r em ent s f r om i nsi de t he d r y we l l once bef or e ent er i ng t he per i od of ex t ended o per at i on and ev er y 10 y ear s du r i ng t he per i od of e x te n d e d o p e ra tio n. T he s t af f's r ev i ew of t he appl i cant's r espo nse det er m i ned t hat t he epox y coa t i ng appl i ed i n t he sand-bed r egi on of t he s hel l has a l i m i t ed l i f e and t hat wat er l eaka ge f r om t he ai r gap ha s no t been pr ev ent ed. W i t h t hese obs er v at i ons, t he s t af f r eques t ed t hat t he appl i cant pr ov i de a s ys te m a tic p ro g ra m o f e x a m in a tio n o f th e c o a tin g f o r c o n f id e n c e th a t th e p re v e n tiv e m e a s u re is a d e q u a te ly im p le m e n te d a t a ll lo c a tio n s in th e s a n d-p o c k e t a re a s. I n i t s r espo nse dat ed J une 20, 2006, t he appl i cant com m i t t ed t o m oni t or i ng t he s and bed r egi on d ra in s o n a d a il y b a s is d u rin g re f u e li n g o u ta g e s a n d ta k e th e f o ll o w in g a c tio n s if w a te r is det ect ed. T he f ol l owi ng ac t i ons wi l l be c om pl et ed pr i or t o ex i t i ng t he out age:
- T he s our ce o f wat er wi l l be i nv est i gat ed and di v er t ed, i f pos si bl e, f r om ent er i ng t he gap b e tw e e n th e d ryw e ll s h e ll a n d th e d ryw e ll s h ie ld w a ll.
- T he wat er wi l l be c hem i cal l y anal y z ed t o ai d i n det er m i ni ng t he s our ce o f l eaka ge.
- A r em ot e i nspe ct i on wi l l be per f or m ed i n t he t r ough dr ai n ar ea t o det er m i ne i f t he t r ough d r a in s a r e o p e r a tin g p r o p e r ly.
- T he c ondi t i on of t he c oat i ng and t he m oi st ur e bar r i er (seal) i n t he af f ect ed bay s wi l l be i nspe ct ed.
- I f t he c oat i ng i s de gr aded an d v i sual i nspe ct i on i ndi cat es c or r osi on i s t aki ng pl ace, t hen U T t hi ck ness m easu r em ent s wi l l be t aken i n t he af f ect ed ar eas of t he s and bed r egi on.T he m easu r em ent s wi l l be t aken f r om ei t her i nsi de or out si de t he dr y wel l t o ens ur e t hat t he sh el l t hi ckness i n ar eas a f f ect ed b y wa t er l eaka ge i s m easu r ed. U T t hi ckness me a s u r e me n t s a n d e v a l u a t i o n w i l l b e c o n s i s t e n t w i t h t h e e x i s t i n g p r o g r a m.
1-17
- T he degr aded c oat i ng and/or t he s eal wi l l be r epai r ed i n ac cor danc e wi t h st at i on pr oced ur es.
- U T m easu r em ent s wi l l be t aken i n t he uppe r r egi on of t he dr y wel l con si st ent wi t h t he e x i s t i n g p r o g r a m.T he appl i cant al so c om m i t t ed (C om m i t m ent N o. 27) t o m oni t or t he s and bed r egi on dr ai ns quar t er l y dur i ng t he oper at i ng c y cl e. T he appl i cant st at ed t hat , i f wat er i s de t ect ed, act i ons l i st ed bel ow wi l l be t aken. Act i ons t hat can onl y be c om pl et ed dur i ng an o ut age wi l l be c om pl et ed dur i ng t he nex t sc hedul ed r ef uel i ng out age.
- T he l eaka ge r at e wi l l be qua nt i f i ed t o det er m i ne a r epr esen t at i v e f l ow r at e. T he l eaka ge r at e wi l l be t r ended.
- T he s our ce o f wat er wi l l be i nv est i gat ed and di v er t ed, i f pos si bl e, f r om ent er i ng t he gap b e tw e e n th e d ryw e ll s h e ll a n d th e d ryw e ll s h ie ld w a ll.
- T he wat er wi l l be c hem i cal l y anal y z ed t o det er m i ne t he s our ce o f l eaka ge.
- T he c ondi t i on of t he c oat i ng and t he m oi st ur e bar r i er (seal) i n t he af f ect ed bay s wi l l be in s p e c te d d u r in g th e n e x t r e f u e lin g o u ta g e o r a n o u ta g e o f o p p o r tu n ity.
- I f t he c oat i ng i s de gr aded an d v i sual i nspe ct i on i ndi cat es c or r osi on has t aken pl ace, t hen U T t hi ck ness m easu r em ent s wi l l be t aken i n t he af f ect ed ar eas of t he s and bed r egi on f r om ei t her i nsi de or out si de t he dr y wel l t o ens ur e t hat t he s hel l t hi ck ness i n ar eas af f ect ed by wat er l eaka ge i s m easu r ed. U T t hi ck ness m easu r em ent s an d ev al uat i on of t h e r e s u l t s w i l l b e c o n s i s t e n t w i t h t h e e x i s t i n g p r o g r a m.
- U T m easu r em ent s wi l l be t aken i n t he uppe r r egi on of t he dr y wel l con si st ent wi t h t he e x i s t i n g p r o g r a m.
- T he d egr ade d coa t i ng o r t he se al wi l l be r epa i r ed i n acco r dan ce w i t h st at i on p r oced ur es.T he s t af f bel i ev es t hat appl i cant had no t pr ov i ded s uf f i ci ent i nf or m at i on r egar di ng t he ex t ent t hat coat ed s ur f aces wi l l be ex am i ned dur i ng eac h i nspe ct i on. T hi s i t em was i dent i f i ed as O pen I t em O I 4.7.2-3 in th e S E R w ith O p e n Ite m s is s u e d in A u g u s t 2 0 0 6. I n a l et t er dat ed J une 23, 2006, t he appl i cant com m i t t ed t o m oni t or i ng of t he c oat i ng on t he d ryw e ll s h e ll e x te rio r in th e s a n d b e d re g io n a s p a rt o f its A S M E S e c tio n X I, S u b s e c tio n IW E Pr ogr am and of i t s Pr ot ect i v e C oat i ng Moni t or i ng and M ai nt enanc e Pr ogr am. T he appl i cant com m i t t ed t o ad di t i ona l v i sual i nspe ct i ons o f t he e poxy coat i ng i n al l 10 d r y we l l bay s at l east once pr i or t o t he per i od of ex t ended o per at i on. I n a l et t er dat ed Decem ber 3, 2006, t he appl i cant st at ed t hat 100 pe r cent of t he epox y coa t i ng had been i nspe ct ed dur i ng t he O ct ober 2006 out age wi t h no ev i denc e of f l aki ng, bl i st er i ng, peel i ng, di sc ol or at i on, or ot her si gns of coa t i ng di st r ess. T he s t af f f i nds t hat t hese com m i t m ent s wi t h t he I W E pr ogr am and t he abs ence of ev i denc e of coa t i ng det er i or at i on i n t he O ct ober 2006 i nspe ct i on r esol v e t he c once r n ov er t he ex t ent of coa t i ngs i nspe ct i ons. T he s t af f's c once r n i s r esol v ed and O pen I t em 4.7.2-3 i s c l osed.
1-18 1.6 Sum mar y o f Co nf irm at or y It emsT he s t af f's r ev i ew of t he LRA , i ncl udi ng addi t i onal i nf or m at i on s ubm i t t ed t o t he s t af f t hr ough D ecem ber 15, 2006, i dent i f i ed no c onf i r m at or y i t em s (C I s). An i ss ue was con si der ed conf i r m at or y i f t he st af f and t he a ppl i cant have r each ed a sat i sf act or y r esol ut i on, but such i n fo rm a t i o n h a s n o t y e t b e e n s u b m i t t e d t o t h e s t a ff.
1.7 Summary of Propose d License Condit ionsAs a r esul t of i t s r ev i ew of t he LRA , r ecom m endat i ons f r om t he Adv i sor y C om m i t t ee on React or Saf eguar ds, and s ubse quent i nf or m at i on and cl ar i f i cat i ons f r om t he appl i cant , t he s t af f , at pr esen t , pr opo ses seven l i cense cond i t i ons.T he f i r st l i cens e co ndi t i on r equi r es t he appl i cant t o i ncl ude t he UF SA R sup pl em ent r equi r ed by 10 CF R 54.21(d) i n t he nex t U FS AR updat e, as r equi r ed by 10 CF R 50.71(e), f ol l owi ng t he i ss uanc e of t he r enewed l i cens e.T he s econ d l i cens e co ndi t i on r equi r es f ut ur e ac t i v i t i es i dent i f i ed i n t he UF SA R sup pl em ent t o be com pl et ed pr i or t o ent er i ng and dur i ng t he per i od of ex t ended o per at i on.T he t hi r d l i cens e co ndi t i on r equi r es a l l sur v ei l l ance cap sul es p l aced i n st or age t o be m ai nt ai ned f or f ut ur e i nser t i on. Any cha nges t o st or age r equi r em ent s m ust be app r ov ed by t he s t af f as r e q u i r e d b y 1 0 CF R P a r t 5 0 , A p p e n d i x H.T he f our t h l i cens e co ndi t i on r equi r es t he appl i cant t o per f or m f ul l sc ope i nspe ct i ons of t he dr y wel l san d bed r egi on ev er y ot her r ef uel i ng out age.T he f i f t h l i cens e co ndi t i on r equi r es t he appl i cant t o m oni t or dr y wel l t r ench es e v er y r ef uel i ng o u ta g e to id e n tify a n d e li m in a te th e s o u rc e s o f w a te r a n d re c e iv e N R C a p p ro v a l p rio r to re s to rin g th e tre n c h e s to th e ir o rig in a l d e s ig n c o n f ig u ra tio n. T he s i x t h l i cens e co ndi t i on r equi r es t he appl i cant t o per f or m an eng i neer i ng s t udy pr i or t o t he p e r i o d o f e x t e n d e d o p e r a t i o n t o i d e n t i f y o p t i o n s t o e l i mi n a t e o r r e d u c e t h e l e a k a g e i n t h e OCGS re fu e l i n g c a v i ty l i n e r.T he s ev ent h l i cens e co ndi t i on r equi r es t he appl i cant t o per f or m a 3-D (di m ensi onal) f i ni t e-e le m e n t a n a ly s is o f th e d ryw e ll s h e ll p rio r to e n te rin g th e p e rio d o f e x te n d e d o p e ra tio n.
Section 3.0.3.2.23 3-114 i nt ended f unct i on(s) wi l l be m ai nt ai ned c onsi st ent wi t h t he CLB f or t he per i od of ex t ended oper at i on, as r equi r ed by 10 CF R 54.21(a)(3). T he s t af f al so r ev i ewed t he UF SA R sup pl em ent f or t hi s AM P and conc l udes t hat i t pr ov i des an adeq uat e su m m ar y des cr i pt i on of t he pr ogr am , a s re q u i re d b y 1 0 C F R 5 4.2 1 (d).
3.0.3.2.2 3 A S M E S e c tio n X I, S u b s e c tio n IW E Sum m ar y of T echn i cal I nf or m at i on i n t he Appl i cat i on. I n LRA Sect i on B.1.27, t he appl i cant desc r i bed t he ex i st i ng AS M E S ect i on XI , Subsec t i on I W E P r ogr am as c onsi st ent , wi t h an e x c e p ti o n , w i th G A L L A M P X I.S 1 , "A S M E S e c ti o n X I, S u b s e c ti o n IW E." T he AS M E S ect i on XI , Subsec t i on I W E P r ogr am pr ov i des f or i nspe ct i on of pr i m ar y con t ai nm ent c o m p o n e n ts a n d th e c o n ta in m e n t v a c u u m b re a k e rs s ys te m p ip in g a n d c o m p o n e n ts. It is i m pl em ent ed t hr ough s t at i on pl ans and pr oced ur es a nd c ov er s s t eel con t ai nm ent she l l s an d t hei r i nt egr al at t achm ent s; con t ai nm ent hat ches and ai r l ock s, sea l s an d gas ket s, con t ai nm ent v acuu m br eake r s s y st em pi pi ng and com ponent s, and pr ess ur e r et ai ni ng bol t i ng. T he pr ogr am i ncl udes v i sual ex am i nat i on and l i m i t ed s ur f ace or v ol um et r i c ex am i nat i on, when aug m ent ed ex am i nat i on i s r equi r ed, t o det ect l oss of m at er i al. T he pr ogr am al so m anages l oss of sea l i ng f o r s e a ls a n d g a s k e ts a n d lo s s o f p re lo a d f o r p re s s u re-re ta in in g b o lti n g. P ro c u re m e n t c o n tro ls and i nst al l at i on pr act i ces , def i ned i n pl ant pr oced ur es, ens ur e t hat onl y appr ov ed l ubr i cant s an d t ensi on or t or que ar e appl i ed. T he pr ogr am com pl i es wi t h Subsec t i on I W E f or st eel c o n ta in m e n ts (C la s s M C) o f A S M E S e c tio n X I, 1 9 9 2 E d iti o n in c lu d in g 1 9 9 2 A d d e n d a , in a c c o rd a n c e w i th th e p ro v i s i o n s o f 1 0 C F R 5 0.5 5 (a).St af f Ev al uat i on. D ur i ng i t s au di t and r ev i ew, t he s t af f r ev i ewed t he appl i cant's c l ai m of c o n s i s te n c y w i th th e G A L L R e p o rt. D e ta i l s o f th e s ta ff's a u d i t e v a l u a ti o n o f th i s A M P a re docu m ent ed i n t he Audi t and Rev i ew R epor t Sect i on 3.0.3.2.23.D ur i ng t he ons i t e audi t s of O ct ober 3-7, 2005, Jan uar y 23-27, 2006, Febr uar y 13-17, 2006, and Apr i l 19-20, 2006, t he s t af f con duct ed an i n-dept h r ev i ew of (1) t he O C G S hi st or y of cont ai nm ent degr adat i on due t o co r r osi on, (2) t he c or r ect i v e ac t i ons t aken at t he t i m e, (3) t he c u rre n t IW E a u g m e n te d in s p e c tio n s a n d o th e r p ro g ra m s a n d a c tiv iti e s to m o n ito r/m iti g a te addi t i onal cor r osi on, and (4) t he appl i cant's l i cens e r enewal com m i t m ent s t o m anage a gi ng of t he degr aded c ont ai nm ent dur i ng t he per i od of ex t ended o per at i on.T h ro u g h th e a u d it p ro c e s s , th e a p p li c a n t m a d e a n u m b e r o f s ig n ific a n t n e w c o m m itm e n ts to m anage a gi ng of t he dr y wel l she l l. H owev er , t hr ee i ss ues r em ai n unr esol v ed. T he s t af f's r ev i ew of t he appl i cant's or i gi nal l i cens e r enewal com m i t m ent s, t he dev el opm ent of t he appl i cant's ne w com m i t m ent s, and t he r em ai ni ng unr esol v ed i ss ues ar e doc um ent ed i n t he Audi t and Rev i ew R e p o rt. T o s u m m a ri ze t h e s t a ff's e va l u a t i o n o f t h e c o n t a i n m e n t c o rr o s i o n i s s u e , t h e s t a ff f o c u s e d o n th e f o ll o w in g f o u r s p e c ific a re a s: (1) wat er l eaka ge f r om t he r ef uel i ng c av i t y i nt o t he annu l us b et ween t he dr y wel l and t he s h ie ld w a ll (2) cor r osi on of t he uppe r dr y wel l r egi on abov e t he f or m er san d bed r egi on (3) c o rro s io n o f th e f o rm e r s a n d b e d re g io n o f th e d ryw e ll (4) pi t t i ng co r r osi on o f t he su ppr essi on ch am ber (t or us) 3-115 T he oper at i ng ex per i ence and pr opos ed agi ng m anagem ent act i v i t i es f or eac h of t hese ar eas wer e r ev i ewed i n det ai l , and ad di t i onal i nf or m at i on was r eques t ed, as n eces sar y , t o f aci l i t at e a t hor oug h asse ssm ent and eval uat i on o f t he a ppl i cant's agi ng m ana gem ent pl ans f or t he l i cense re n e w a l p e rio d. T h e re s u lts o f th is d e ta il e d a u d it a re d o c u m e n te d in th e f o ll o w in g p a ra g ra p h s. In addi t i on, t he s t af f's ev al uat i on of t he i nf or m at i on i n eac h of t hese f our ar eas i s pr esen t ed unde r th e d ryw e ll d e g ra d a tio n is s u e a t th e e n d o f th is s e c tio n.
W at er Leak age f r om t he Ref uel i ng Cav i t y. D ur i ng t he audi t , t he appl i cant st at ed t hat a sp eci al coat i ng i s ap pl i ed t o t he r ef uel i ng c av i t y l i ner pr i or t o f l oodi ng t he r eact or f or r ef uel i ng t o pr ev ent l eaka ge i nt o t he a nnu l ar space bet we en t he d r y we l l shel l and t he co ncr et e shi el d w al l. A s a r esul t , t he appl i cant bel i ev es t hat wat er i nt r usi on i nt o t he r ef uel i ng c av i t y has been e l i m i nat ed as a s o u rc e o f f u rth e r d e g ra d a tio n o n th e e x te rio r s u rf a c e o f th e d ryw e ll s h e ll.Si nce t he appl i cant use d t hi s s peci al coa t i ng t o m i ni m i z e wat er i nt r usi on i nt o t he annu l us b e t w e e n t h e d ry w e l l a n d t h e c o n c re t e s h i e l d w a l l; t h e s t a ff r e q u e s t e d t h a t t h e a p p l i c a n t i d e n t i fy whet her i t i s c om m i t t ed t o co nt i nue t he us e of t hi s s peci al coa t i ng as par t of i t s r ef uel i ng p ro c e d u re t h ro u g h t h e p e ri o d o f e xte n d e d o p e ra t i o n. I f n o t , t h e a p p l i c a n t w a s a s k e d t o i d e n t i fy what enhanc ed i nspe ct i ons wi l l be c onduc t ed dur i ng t he per i od of ex t ended o per at i on t o m oni t or pot ent i al cor r osi on on t he dr y wel l ex t er i or sur f ace f r om t he uppe r f l ange r egi on t o t he s and bed r egi on.I n i t s r espo nse, t he appl i cant st at ed t hat t he s t r i ppabl e co at i ng has been e f f ect i v e i n m i t i gat i ng wat er i nt r usi on i nt o t he annu l ar spa ce a nd i n r educ i ng t he r at e of cor r osi on. T he appl i cant com m i t t ed t o appl y i ng t he s t r i ppabl e co at i ng t o t he r eact or cav i t y l i ner pr i or t o f l oodi ng f or r ef uel i ng dur i ng t he per i od of ex t ended o per at i on. I n i t s l et t er dat ed Apr i l 4, 2006, t he appl i cant c o m m itte d (C o m m itm e n t N o. 2 7) to th e f o ll o w in g: C onsi st ent wi t h cu r r ent pr act i ce, a st r i ppabl e co at i ng wi l l be app l i ed t o t he r eact or c a v ity li n e r to p re v e n t w a te r in tru s io n in to th e g a p b e tw e e n th e d ryw e ll s h ie ld w a ll a n d th e d ryw e ll s h e ll d u rin g p e rio d s w h e n th e re f u e li n g c a v ity is f lo o d e d. T h is com m i t m ent appl i es t o r ef uel i ng out ages pr i or t o and d ur i ng t he per i od of ex t ended o per at i on.I n r e v i e w i n g P B D-A M P-B.1.2 7 f o r t h e a p p l i c a n t's A S M E S e c t i o n X I , S u b s e c t i o n I W E P r o g r a m, t he s t af f not ed t hat , page 7 of t hi s do cum ent st at es t hat , "U nder t he c ur r ent t er m , O y st er C r eek i s c om m i t t ed t o t he NR C t o m oni t or t he f or m er san d bed r egi on dr ai ns f or wat er l eaka ge. T he com m i t m ent i s t o i nvest i gat e t he so ur ce of l eaka ge, t ake co r r ect i v e act i ons, eval uat e t he i m pact o f th e le a k a g e a n d , if n e c e s s a ry, p e rf o rm a d d iti o n a l d ryw e ll in s p e c tio n s. T h is c o m m itm e n t w il l be i m pl em ent ed dur i ng t he per i od of ex t ended o per at i on. T hi s i s a n ew com m i t m ent not pr ev i ousl y i dent i f i ed i n t he LRA." I n i t s l et t er dat ed Apr i l 4, 2006, t he appl i cant com m i t t ed (C om m i t m ent N o. 27) t o t he f ol l owi ng: T he r eact or cav i t y sea l l eaka ge t r ough dr ai ns a nd t he d r yw e ll s a n d b e d re g io n d r a in s w ill b e m o n ito r e d f o r w a te r le a k a g e p e r io d ic a lly.T he s t af f r eques t ed t hat t he appl i cant des cr i be t hi s c om m i t m ent i n m or e det ai l. I n i t s r espo nse, t h e a p p l i c a n t s t a t e d t h a t t h e c o m m i t m e n t f o r mon i t o r i n g t h e s a n d b e d d r a i n s i s i n a s t a f f SER tra n s m i tt e d b y l e tt e r N o v e m b e r 1 , 1 9 9 5. T h i s S E R re q u e s te d a c o m m i tm e n t t o p e rfo rm i nspe ct i ons "3 m ont hs af t er t he d i scover y of any wa t er l eaka ge." S ubse que nt cor r espo nde nce f r om G ener al Publ i c Ut i l i t i es Nucl ear C or por at i on (G PU N) cl ar i f i ed t he c om m i t m ent af t er 3-116 di sc uss i ons wi t h t he s t af f. T he c om m i t m ent m ade and acc ept ed by t he s t af f i n a Febr uar y 15, 1996, l et t er was t o per f or m addi t i onal i nspe ct i ons of t he dr y wel l 3 m ont hs a f t er di scover y of any wa t er l eaka ge d ur i ng p ow er ope r at i on b et we en sch edu l ed d r y we l l i nspe ct i ons.T h e re q u ire m e n t w a s n o t m e a n t to a p p ly to m in o r le a k a g e f ro m n o rm a l re f u e li n g a c tiv iti e s. T h is com m i t m ent i s c onsi st ent wi t h t he pr esen t com m i t m ent i n PB D-AM P-B.1.27.T he appl i cant f ur t her st at ed i n i t s r espo nse t hat , al t hough t her e i s no f or m al l eaka ge m oni t or i ng i n pl ace, t her e ha s bee n no r epo r t ed e v i den ce of l eaka ge f r om t he f or m er sand bed dr ai ns.I ss ue Repor t #34854 5 was subm i t t ed i nt o t he c or r ect i v e ac t i on pr oces s when t hi s l ack of f or m al l eaka ge m oni t or i ng was di sc ov er ed. C or r ect i v e ac t i ons hav e been i ni t i at ed t o cr eat e r ecur r i ng act i v i t i es c ont r ol l ed by wor k m anagem ent pr oces s an d pr oced ur es f or al l f ut ur e r equi r ed i nspe ct i ons t o m eet t he pr esen t com m i t m ent. Becaus e t her e has been n o r epor t ed l eaka ge, th e re h a s b e e n n o n e e d to in v e s tig a te th e s o u rc e o f le a k a g e , ta k e c o rre c tiv e a c tio n s , e v a lu a te t he i m pact of l eaka ge, or per f or m add i t i ona l dr y we l l i nspe ct i ons.T he appl i cant f ur t her st at ed t hat num er ous act i ons hav e been t aken t o al l ev i at e t he pr ev i ous wat er l eaka ge pr obl em si nce di sc ov er y of t he c onse quent dr y wel l she l l cor r osi on. Som e of t he si gni f i cant act i ons cons i st ed of i nspe ct i ons of t he r eact or cav i t y wal l , r em ot e v i sual i nspe ct i on of t he t r ough ar ea bel ow t he r eact or cav i t y bel l ows s eal ar ea, and s ubse quent r epai r of t he t r ough ar ea and cl ear i ng of i t s dr ai n. C l ear i ng of t he t r ough dr ai n and r epai r of t he t r ough r out e any l eaka ge away f r om t he dr y wel l she l l. I n addi t i on, a st r i ppabl e co at i ng i s ap pl i ed t o t he r eact or c a v ity w a ll s b e f o re th e re a c to r c a v ity is f il le d w ith w a te r to m in im ize th e li k e li h o o d o f le a k a g e in to t he t r ough ar ea. T hese pr ev ent i v e ac t i ons hav e r esul t ed i n no ev i denc e of l eaka ge ov er t he ye a rs a t th e f o rm e r s a n d b e d d ra in s. D ur i ng t he AC R S m eet i ng on Febr uar y 1, 2007, t he appl i cant agr eed t o per f or m an eng i neer i ng st udy t o i nv est i gat e co st-ef f ect i v e r epl acem ent or r epai r opt i ons t o el i m i nat e or r educ e r eact or cav i t y l i ner l eaka ge. By l et t er dat ed Febr uar y 15, 2007, t he appl i cant , i n C om m i t m ent N um ber 27, "AS M E S ect i on XI , Subsec t i on I W E," i t em 19, com m i t t ed t o co m pl et e t he engi neer i ng s t udy p rio r to th e p e rio d o f e x te n d e d o p e ra tio n s. C or r osi on o f t he U ppe r D r y we l l abo v e t he F or m er S and B ed R egi on. I n r evi ew i ng t he l i cense r enewal i nf or m at i on f or t he uppe r r egi on of t he dr y wel l she l l , t he s t af f not ed t hat t he appl i cant r ef er r ed t o t he LRA Sect i on 4.7.2, "D r y wel l C or r osi on," T LAA ev al uat i on f or f ur t her di sc uss i on.In L R A S e c tio n 4.7.2 , th e a p p li c a n t s ta te d th a t th e d is p o s iti o n o f th is T L A A is in a c c o rd a n c e w ith 1 0 C F R 5 4.2 1 (c)(1)(iii), a n d th e A S M E S e c tio n X I, S u b s e c tio n IW E P ro g ra m is c re d ite d to addr ess t he dr y wel l cor r osi on T LAA. I n LRA Sect i on 4.7.2, under Anal y si s, t he appl i cant st at ed t hat t he AS M E S ect i on XI , Subsec t i on I W E P r ogr am ens ur es t hat t he r educ t i on i n v ess el t hi ck ness wi l l not adv er sel y af f ect t he abi l i t y of t he dr y wel l t o per f or m i t s s af et y f unct i on. T he AS M E S ect i on XI , Subsec t i on I W E P r ogr am per f or m s pe r i odi c UT i nspe ct i ons at cr i t i cal l ocat i ons, per f or m s c al cul at i ons t o t r ack cor r osi on r at es, pr oj ect s v ess el t hi ck ness bas ed on cons er v at i v e co r r osi on r at es, and de m onst r at es m ai nt enanc e of t he m i ni m um r equi r ed v ess el t hi ckness.T h e a p p li c a n t fu rth e r s ta te d in th e L R A th a t in s p e c tio n s c o n d u c te d s in c e 1 9 9 2 d e m o n s tra te th a t, as a r esul t of cor r ect i v e ac t i ons, t he c or r osi on r at es a r e v er y l ow or , i n so m e ca ses , ar r est ed.T h e d ryw e ll s u rf a c e s th a t w e re c o a te d s h o w n o s ig n s o f d e te rio ra tio n. D ryw e ll v e s s e l w a ll t hi ck ness m easu r em ent s i ndi cat e su bst ant i al m ar gi n t o t he m i ni m um wal l t hi ck ness , ev en when pr oj ect ed t o t he y ear 2029 wi t h co nser v at i v e es t i m at es o f cor r osi on r at es. T he appl i cant st at ed t hat con t i nued as ses sm ent of t he obs er v ed dr y wel l v ess el t hi ck ness ens ur es t hat t i m el y act i on can be t aken t o co r r ect degr adat i on t hat cou l d l ead t o l oss of t he i nt ended f unct i on.
3-117 T he s t af f r ev i ewed t he appl i cant's di sc uss i on of agi ng m anagem ent act i v i t i es f or t he uppe r r egi on of t he dr y wel l she l l and de t er m i ned t hat addi t i onal i nf or m at i on was needed on t he augm ent ed s cope of I W E. I n i t s r espo nse, t he appl i cant st at ed t hat O C G S had been c om m i t t ed t o t he dr y wel l cor r osi on pr ogr am i n 1986 bef or e i m pl em ent at i on of I W E i n Sept em ber 9, 2001.T h e p ro g ra m e le m e n ts , in c lu d in g p e rio d ic U T in s p e c tio n s a t c ritic a l l o c a tio n s , c a lc u la tio n s to t r ack cor r osi on r at es, v ess el t hi ck ness pr oj ect i ons base d on c onse r v at i v e co r r osi on r at es, and dem onst r at i ons of m ai nt enanc e of m i ni m um r equi r ed v ess el t hi ck ness , ar e now i ncor por at ed i nt o I W E as an aug m ent ed i nspe ct i on. T he appl i cant pr ov i ded pr oced ur es ER-AA-330, ER-AA-33 0-00 7, O C-6, an d 2 40 0-G MM-39 00.52 f or r ev i ew.T h e a p p li c a n t fu rth e r s ta te d in its re s p o n s e th a t e x a m in a tio n o f th e d ryw e ll in te rio r s u rf a c e s in t he f or m er sand bed r egi on i s i ncl ude d as p ar t of t he A S M E C ode S ect i on XI I W E i nspe ct i ons.T he i nspe ct i on of t he ex t er i or sur f aces of t he dr y wel l i n t he s and bed r egi on i s i ncl uded i n t he P r o t e c t i v e C o a t i n g M o n i t o r i n g a n d M a i n t e n a n c e P r o g r a m.T he appl i cant al so p r ov i ded a t abul at i on of m easu r ed t hi ck ness es f or t he m oni t or ed el ev at i on of t he u ppe r r egi on o f t he d r y we l l shel l al ong wi t h cal cul at i on 1 302-187-E 310-003 7, wh i ch sum m ar i z es t r endi ng r esul t s, pr oj ect ed r em ai ni ng wal l t hi ck ness at t he end of t he per i od of ext end ed o per at i on, and t he C LB m i ni m um r equ i r ed t hi ckness.T he appl i cant f ur t her st at ed t hat U T i nspe ct i ons ar e per f or m ed ev er y ot her r ef uel i ng out age and t hat cal cul at i on 1302-187-E310-0037 pr ov i des t he c or r osi on c al cul at i on and end-of-oper at i ng l i f e t hi ck ness cal cul at i on.I n i t s l e t t e r d a t e d A p r i l 4 , 2 0 0 6 , t h e a p p l i c a n t c o mmi t t e d (Co mmi t me n t No. 2 7) t o c o n d u c t UT t hi ck ness m easu r em ent s i n t he uppe r r egi ons of t he dr y wel l she l l ev er y ot her r ef uel i ng out age a t th e s a m e lo c a tio n s c u rre n tly m e a s u re d p rio r to a n d d u rin g th e p e rio d o f e x te n d e d o p e ra tio n. I n r e v i e w i n g P B D-A M P-B.1.2 7 f o r t h e a p p l i c a n t's A S M E S e c t i o n X I , S u b s e c t i o n I W E P r o g r a m, t he s t af f not ed t hat , i n t he di sc uss i on on p ages 25 t hr ough 31 of dr y wel l cor r osi on abov e t he s a n d b e d re g io n , th e a p p li c a n t s ta te d th a t, C or r ect i v e ac t i on f or t hese r egi ons i nv ol v ed pr ov i di ng a c or r osi on al l owanc e by dem onst r at i ng, t hr ough an al y si s, t hat t he or i gi nal dr y wel l des i gn pr ess ur e was cons er v at i v e. Am endm ent 165 t o t he O y st er C r eek T echn i cal Speci f i cat i ons r educ ed t he dr y wel l des i gn pr ess ur e f r om 62 ps i g t o 44 ps i g. T he new de si gn pr ess ur e co upl ed wi t h m easu r es t o pr ev ent wat er i nt r usi on i nt o t he gap bet ween th e d ryw e ll s h e ll a n d th e c o n c re te w il l a ll o w th e u p p e r p o rtio n o f th e d ryw e ll to m eet A S M E C ode r equ i r em ent s.D ur i ng t he audi t , t he s t af f r eques t ed t hat t he appl i cant des cr i be t he m easu r es t o pr ev ent wat er i nt r usi on i nt o t he gap bet ween t he dr y wel l she l l and t he c oncr et e t o al l ow t he uppe r por t i on of th e d ryw e ll to m e e t A S M E C o d e re q u ire m e n ts. In a d d iti o n , th e a p p li c a n t w a s f u rth e r a s k e d to c la rif y w h e th e r th e s e m e a s u re s to p re v e n t w a te r in tru s io n w e re c re d ite d f o r lic e n s e re n e w a l, and, i f not , t o cl ar i f y how AS M E C ode r equi r em ent s wi l l be m et dur i ng t he per i od of ex t ended oper at i on.I n i t s r espo nse, t he appl i cant st at ed t hat t he m easu r es t aken t o pr ev ent wat er i nt r usi on i nt o t he g a p b e tw e e n th e d ryw e ll s h e ll a n d th e c o n c re te to a ll o w th e u p p e r p o rtio n o f th e d ryw e ll to m ai nt ai n t he AS M E C ode r equi r em ent s ar e t he f ol l owi ng:
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- C l ear ed t he f or m er san d bed r egi on dr ai ns t o i m pr ov e t he dr ai nage pa t h.
- R epl aced r eact or cav i t y st eel t r ough dr ai n gas ket , whi ch was f ound t o be l eaki ng.
- Appl i ed s t ai nl ess st eel t y pe t ape and st r i ppabl e co at i ng t o t he r eact or cav i t y dur i ng re fu e l i n g o u ta g e s to s e a l i d e n ti fie d c ra c k s i n th e s ta i n l e s s s te e l l i n e r.
- C onf i r m ed t hat t he r eact or cav i t y con cr et e t r ough dr ai ns a r e not cl ogged.
- M oni t or ed f or m er san d bed r egi on dr ai ns a nd r eact or cav i t y con cr et e t r ough dr ai ns f or l eaka ge dur i ng r ef uel i ng out ages and pl ant oper at i on.T he appl i cant f ur t her st at ed t hat O C G S i s c om m i t t ed t o i m pl em ent t hese m easu r es d ur i ng t he per i od of ex t ended o per at i on.
C or r osi on of t he For m er Sand Bed R egi on of t he Dr y wel l. I n r ev i ewi ng i nf or m at i on f or t he s and b e d re g io n a t th e b o tto m o f th e d ryw e ll , th e s ta f f n o te d th a t, in th e A S M E S e c tio n X I, Subsect i on I W E P r ogr am di sc uss i on of oper at i ng ex per i ence , t he appl i cant had s t at ed t hat san d was r em ov ed and a pr ot ect i v e co at i ng was appl i ed t o t he s hel l t o m i t i gat e f ur t her cor r osi on. T he coat i ng i s m oni t or ed p er i odi cal l y und er t he P r ot ect i v e C oat i ng M oni t or i ng a nd M ai nt ena nce P r o g r a m , w h i c h i s d i s c u s s e d i n S E R S e c t i o n 3.0.3.2.2 7. T h e s t a ff r e vi e w e d t h e P r o t e c t i ve C oat i ng Moni t or i ng and M ai nt enanc e Pr ogr am and de t er m i ned t hat t he c oat i ng i s i ncl uded w i t h i n i t s s c o p e. T h e s t a ff n o t e d t h a t t h e d i s c u s s i o n o f op e r a t i n g e xp e r i e n c e i n t h e P r o t e c t i ve C oat i ng Moni t or i ng and M ai nt enanc e Pr ogr am i s s i m i l ar t o t he di sc uss i on of oper at i ng e x p e r i e n c e i n A S M E S e c t i o n X I , S u b s e c t i o n I W E P r o g r a m.T he s t af f r ev i ewed t he appl i cant's ag i ng m anagem ent act i v i t i es f or t he f or m er san d bed r egi on of t he dr y wel l she l l and de t er m i ned t hat addi t i onal i nf or m at i on was needed on agi ng m anagem ent of t hi s r egi on. I n i t s r espo nse, t he appl i cant st at ed t hat m oni t or i ng and m ai nt enanc e of t he c oat i ng i n t he f or m er san d bed r egi on ar e i ncl uded i n t he s cope of t he P r ot ect i v e C oat i ng M oni t or i ng a nd M ai nt ena nce P r ogr am. T hese act i v i t i es ar e i n acco r dan ce w i t h s p e c i f i c a t i o n s S P-1 3 0 2-3 2-0 3 5 a n d S P-9 0 0 0-0 6-0 0 3 , w h i c h a r e i n c l u d e d i n t h e p r o g r a m.T h e a p p li c a n t fu rth e r s ta te d in its re s p o n s e th a t a g in g m a n a g e m e n t o f th e s a n d b e d re g io n is n o t i n c l u d e d i n t h e a u g m e n t e d i n s p e c t i o n r e q u i r e d b y ASM E Co d e Se c t i o n X I , Su b s e c t i o n I W E.As st at ed i n AS M E C ode Sect i on XI , Subsec t i on I W E oper at i ng ex per i ence , cor r ect i v e ac t i ons t hat i ncl ude c l eani ng and coat i ng of t he s and bed r egi on i m pl em ent ed i n 1992 hav e ar r est ed cor r osi on. T he c oat ed s ur f aces wer e i nspe ct ed i n 1994, 1996, 2000, and 20 04, and t he in s p e c tio n s h o w e d n o c o a tin g f a il u re o r s ig n s o f d e g ra d a tio n. T h u s , th e re g io n is n o t s u b je c t to augm ent ed i nspe ct i on i n ac cor danc e wi t h I W E-1240. T he c oat i ng wi l l be i nspe ct ed ev er y ot her r ef uel i ng out age dur i ng t he per i od of ex t ended o per at i on c onsi st ent wi t h co m m i t m ent s f or t he c u r r e n t t e r m.As a r esul t of di sc uss i ons bet ween t he s t af f and t he appl i cant on J anuar y 26, 2006, and Apr i l 20, 2006, t he appl i cant sup pl em ent ed i t s i ni t i al r espo nse t o i ncl ude t he f ol l owi ng:
- O C G S wi l l al so p er f or m per i odi c UT i nspe ct i ons of t he dr y wel l she l l t hi ck ness i n t he s and bed r egi on, as d i sc uss ed pr ev i ousl y i n t hi s s ect i on.
- O C G S w il l a ls o e n h a n c e th e P ro te c tiv e C o a tin g M o n ito rin g a n d M a in te n a n c e P ro g ra m to r equi r e i nspe ct i on of t he c oat i ng c r edi t ed f or cor r osi on (t or us i nt er nal , v ent sy st em i nt er nal , san d bed r egi on ex t er nal) i n ac cor danc e wi t h AS M E S ect i on XI , Subsec t i on I W E P r ogr am. D et ai l s ar e pr ov i ded l at er i n t hi s s ect i on.
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- O n Apr i l 20, 2006, O C G S pr ov i ded s uppl em ent al i nf or m at i on on t or us c oat i ng.D et ai l s of t he enha ncem ent t o t he Pr ot ect i v e C oat i ng Moni t or i ng and M ai nt enanc e Pr ogr am and t he s t af f's ev al uat i on of t hi s AM P ar e di sc uss ed i n SE R Sect i on 3.0.3.2.27.A f t er t he a ppl i cant's i ni t i al r espo nse, t he a ppl i cant wa s asked f or i t s t echn i cal basi s f or not al so c re d iti n g its A S M E S e c tio n X I, S u b s e c tio n IW E P ro g ra m f o r m a n a g in g lo s s o f m a te ria l d u e to c o rro s io n in th e f o rm e r s a n d b e d re g io n o f th e d ryw e ll.T h e a p p li c a n t s ta te d th a t v is u a l i n s p e c tio n o f th e c o n ta in m e n t d ryw e ll s h e ll , c o n d u c te d in acc or danc e wi t h AS M E C ode Sect i on XI , Subsec t i on I W E, i s c r edi t ed f or agi ng m anagem ent of acc ess i bl e ar eas of t he c ont ai nm ent dr y wel l she l l. T y pi cal l y t hi s i nspe ct i on i s f or i nt er nal sur f aces of t he dr y wel l. T he ex t er i or sur f aces of t he dr y wel l she l l i n t he s and bed r egi on f or Ma r k I c o n t a i n m e n t a r e c o n s i d e r e d i n a c c e s s i b l e b y ASM E Co d e Se c t i o n X I , Su b s e c t i o n I W E;t hus, v i sual i nspe ct i on was not pos si bl e f or a t y pi cal Mar k I con t ai nm ent bef or e t he s and was r em ov ed f r om t he s and bed r egi on i n 1992. Af t er r em ov al of t he s and, an epo x y coa t i ng was appl i ed t o t he ex t er i or sur f aces of t he dr y wel l she l l i n t he s and bed r egi on. T he r egi on was m a d e a c c e s s ib le d u r in g re f u e lin g o u ta g e s f o r p e r io d ic in s p e c tio n o f th e c o a tin g. S u b s e q u e n tly, O C G S p e rio d ic a ll y v is u a ll y i n s p e c te d th e c o a tin g u n d e r a C L B c o m m itm e n t im p le m e n te d p rio r to th e A S M E S e c tio n X I, S u b s e c tio n IW E P ro g ra m. A s a re s u lt, i n s p e c tio n o f th e c o a tin g w a s in a c c o rd a n c e w ith th e P ro te c tiv e C o a tin g M o n ito rin g a n d M a in te n a n c e P ro g ra m. T h e a p p li c a n t's e v a lu a tio n o f th is A M P c o n c lu d e d th e p ro g ra m is a d e q u a te to m a n a g e a g in g o f th e d ryw e ll s h e ll i n t he s and bed r egi on dur i ng t he per i od of ex t ended o per at i on c onsi st ent wi t h t he CLB com m i t m ent and t hat i ncl usi on of t he c oat i ng i nspe ct i on unde r t he AS M E I W E i nspe ct i on i s no t r e q u i r e d. H o w e ve r , t h e a p p l i c a n t w i l l a m e n d t h i s p o s i t i o n t o c o m m i t t o m o n i t o r t h e p r o t e c t i ve coat i ng on t he ex t er i or sur f aces of t he dr y wel l i n t he s and bed r egi on i n ac cor danc e wi t h t he r equi r em ent s of AS M E C ode Sect i on XI , Subsec t i on I W E dur i ng t he per i od of ex t ended o p e ra tio n. I n i t s l et t er dat ed Apr i l 4, 2006, t he appl i cant com m i t t ed (C om m i t m ent N o. 27) t o t he f ol l owi ng: Pr i or t o t he per i od of ex t ended o per at i on, t he appl i cant wi l l per f or m addi t i onal v i sual i nspe ct i ons of t he e poxy coat i ng a ppl i ed t o t he e x t er i or sur f ace o f t he d r y we l l shel l i n t he sa nd b ed r egi on so t he c oat ed s ur f aces i n al l 10 dr y wel l bay s wi l l hav e been i nspe ct ed at l east onc e. I n addi t i on, t he I SI pr ogr am wi l l be enh ance d t o r equi r e i nspe ct i on of 100 pe r cent of t he epox y coa t i ng ev er y 10 ye a rs d u rin g th e p e rio d o f e x te n d e d o p e ra tio n. T h e s e in s p e c tio n s w il l b e in a c c o rd a n c e w ith A S M E C ode S ect i on XI , S ubse ct i on I W E. T he i nspe ct i ons w i l l be st agg er ed so t hat at l east t hr ee bay s wi l l be ex am i ned ev er y ot her r ef uel i ng out age.I n i t s l et t er dat ed Apr i l 4, 2006, t he appl i cant com m i t t ed (C om m i t m ent N o. 27) t o t he f ol l owi ng: U T t hi ckness m easu r em ent s of t he d r y we l l shel l i n t he sa nd b ed r egi on w i l l be e v er y 10 y ear s.T h e in iti a l i n s p e c tio n w il l o c c u r p rio r to th e p e rio d o f e x te n d e d o p e ra tio n. T h e U T m e a s u re m e n ts wi l l be t aken f r om t he i nsi de of t he dr y wel l at t he s am e l ocat i ons of U T m easu r em ent s i n 1996.T he i nspe ct i on r esul t s wi l l be c om par ed t o pr ev i ous r esul t s. St at i st i cal l y si gni f i cant dev i at i ons f r om t he 1992 , 1994, and 19 96 UT m easu r em ent s wi l l r esul t i n co r r ect i v e ac t i ons: (1) addi t i onal U T m easu r em ent s t o co nf i r m t he r eadi ngs, (2) not i ce t o t he s t af f wi t hi n 48 ho ur s of con f i r m at i on of t he c ondi t i on, (3) v i sual i nspe ct i on of t he ex t er nal sur f ace i n t he s and bed r egi on i n ar eas wher e any unex pect ed c or r osi on m ay be det ect ed, (4) an eng i neer i ng ev al uat i on of t he ex t ent o f c o n d itio n to d e te r m in e w h e th e r a d d itio n a l in s p e c tio n s a r e re q u ir e d to a s s u r e d r yw e ll in te g r ity, and (5) an ope r abi l i t y det er m i nat i on and j ust i f i cat i on f or oper at i on unt i l t he nex t i nspe ct i on.T h e s e a c tio n s w il l b e c o m p le te d p rio r to re s ta rt f ro m th e o u ta g e.
3-120 I n i t s l et t er dat ed May 1, 2006, t he appl i cant com m i t t ed (C om m i t m ent N o. 27) t o t he f ol l owi ng: D ur i ng t he nex t U T i nspe ct i ons of t he dr y wel l san d bed r egi on (r ef er ence Am er G en Apr i l 4, 2006, l et t er t o N R C), an at t em pt wi l l be m ade t o l ocat e and e v al uat e so m e of t he l ocal l y t hi nned ar eas i d e n t i f i e d i n t h e 1 9 9 2 i n s p e c t i o n f r o m t h e e x t e r i o r o f t h e d r y w e l l. Th i s t e s t i n g w i l l u s e t h e l a t e s t UT m e th o d o lo g y w ith e x is tin g s h e ll p a in t in p la c e. T h e U T th ic k n e s s m e a s u re m e n ts f o r th e s e lo c a ll y th in n e d a re a s m a y b e ta k e n f ro m e ith e r in s id e o r o u ts id e th e d ryw e ll (s a n d b e d re g io n) to li m it ra d ia tio n d o s e to a s lo w a s re a s o n a b ly a c h ie v a b le. T he s t af f r eques t ed t hat t he appl i cant pr ov i de a di sc uss i on of t he s cope of t he c ur r ent coa t i ng i nspe ct i on pr ogr am and t he l i cens e r enewal com m i t m ent. I n i t s r espo nse t he appl i cant st at ed th a t p ro te c ti v e c o a ti n g s o n th e e x te ri o r s u rfa c e s o f th e d ry w e l l s h e l l i n th e s a n d b e d re g i o n a re m oni t or ed i n ac cor danc e wi t h t he Pr ot ect i v e C oat i ng Moni t or i ng and M ai nt enanc e Pr ogr am. T he cur r ent pr ogr am r equi r es v i sual i nspe ct i on of t he c oat i ng i n ac cor danc e wi t h Engi neer i ng S p e c i fic a ti o n IS-3 2 8 2 2 7-0 0 4. I n s p e c ti o n c ri te ri a a re n o t p ro v i d e d b y th e s p e c i fic a ti o n. H o w e v e r, i nspe ct i ons ar e by i ndi v i dual s qu al i f i ed f or coa t i ng i nspe ct i ons. Accept ance cr i t er i a i n t he spec i f i cat i on ar e t hat any coa t i ng def ect s be sub m i t t ed f or engi neer i ng ev al uat i on. T he i nspe ct i on f r equenc y i s ev er y ot her r ef uel i ng out age.T he appl i cant f ur t her st at ed i n i t s r espo nse t hat , as d i sc uss ed wi t h t he s t af f , t he ex i st i ng P ro te c tiv e C o a tin g M o n ito rin g a n d M a in te n a n c e P ro g ra m d o e s n o t in v o k e a ll o f th e re q u ire m e n ts of AS M E C ode Sect i on XI , Subsec t i on I W E. T he appl i cant has com m i t t ed (C om m i t m ent N o. 27)to e n h a n c e th e p ro g ra m to in c o rp o ra te c o a te d s u rf a c e s in s p e c tio n re q u ire m e n ts s p e c ifie d in AS M E C ode Sect i on XI , Subsec t i on I W E and has p r ov i ded s peci f i c en hanc em ent s t hat wi l l be m ad e t o t he pr og r am as f ol l ow:S a n d b e d re g i o n e x te rn a l c o a ti n g i n s p e c ti o n s w i l l b e p e r E x a m i n a ti o n C a te g o ry E-C (augm ent ed ex am i nat i on) and wi l l r equi r e VT-1 v i sual ex am i nat i ons per I W E-3412.1. a.
T he i nspe ct ed ar ea s hal l be ex am i ned (as a m i ni m um) f or ev i denc e of f la k in g , b li s te rin g , p e e li n g , d is c o lo ra tio n , a n d o th e r s ig n s o f d is tre s s. b.
Ar eas t hat ar e su spec t sha l l be di spos i t i oned by engi neer i ng ev al uat i on or c o rre c te d b y re p a ir o r re p la c e m e n t in a c c o rd a n c e w ith IW E-3 1 2 2. c.
Suppl em ent al ex am i nat i ons i n ac cor danc e wi t h I W E-3200 s hal l be per f or m ed when s peci f i ed as a r esul t of engi neer i ng ev al uat i on.D u rin g th e a u d it, th e s ta f f a s k e d th e a p p li c a n t fo r in f o rm a tio n re la te d to in s p e c tio n s o f th e d ryw e ll sand bed r egi on. I n r espo nse, t he appl i cant st at ed t hat t he m i ni m um r ecor ded t hi ck ness i n t he s a n d b e d re g io n f ro m a p p ro x im a te ly 1 2 0 U T m e a s u re m e n ts ta k e n o n th e o u ts id e o f th e d ryw e ll s h e l l i s 0.6 1 8". Th e mi n i mu m r e c o r d e d t h i c k n e s s i n t h e s a n d b e d r e g i o n f r o m t h e 6" b y 6" UT m e a s u re m e n t g ri d s i n s i d e th e d ry w e l l s h e l l i s 0.6 0 3". T h e s e m i n i m u m re c o rd e d th i c k n e s s e s a re i sol at ed l ocal m easu r em ent s and r epr esen t si ngl e po i nt U T m easu r em ent s.O n Apr i l 19, 2006, t he appl i cant sup pl em ent ed i t s r espo nse, st at i ng t hat t he l owest r ecor ded r eadi ng was 0.603 i n D ecem ber 1992. T he appl i cant st at ed t hat a r ev i ew of t he pr ev i ous re a d in g s f o r th e p e rio d 1 9 9 0 th ro u g h 1 9 9 2 a n d tw o s u b s e q u e n t re a d in g s ta k e n in Sept em ber 1994 a nd i n 1996 shows t hat t hi s po i nt sho ul d not be c onsi der ed v al i d. T he av er age r eadi ng f or t hi s po i nt t aken i n 1994 and 199 6 was 0.888 i nche s. Poi nt 14 i n l ocat i on 17D was t he n e x t lo w e s t v a lu e o f 0.6 4 6 in c h e s re c o rd e d d u rin g th e 1 9 9 4 o u ta g e. A re v ie w o f re a d in g s a t th is s a m e p o in t, ta k e n d u rin g th e p e rio d f ro m 1 9 9 0 th ro u g h 1 9 9 2 , a n d s u b s e q u e n t re a d in g s ta k e n in 3-121 1996 ar e co nsi st ent wi t h t hi s v al ue. T hus, t he m i ni m um r ecor ded t hi ck ness i n t he s and bed re g io n f ro m in s id e in s p e c tio n s is 0.6 4 6 in c h e s in s te a d o f 0.6 0 3 in c h e s. T h e a p p l i c a n t fu rt h e r sta t e d i n i t s re s p o n s e t h a t t h e 0.8 0 6 i n c h e s t h i c k n e s s p ro vi d e d t o t h e s t a ff v e rb a ll y i s a n a v e ra g e m in im u m g e n e ra l th ic k n e s s c a lc u la te d b a s e d o n 4 9 U T m e a s u re m e n ts t aken i n an ar ea appr ox i m at el y 6 i nche s x 6 i nche s. T hus, t he t wo l ocal i sol at ed m i ni m um r ecor ded t hi ck ness es c annot be c om par ed di r ect l y t o t he gene r al t hi ck ness of 0.806 i nche s. T he 0.8 0 6 in c h e s m in im u m a v e ra g e th ic k n e s s v e rb a ll y d is c u s s e d w ith th e s ta f f d u rin g th e A M P a u d it was r ecor ded i n l ocat i on 19A i n 1994. Lower m i ni m um av er age t hi ck ness v al ues wer e r ecor ded at t he s am e l ocat i on i n 1991 (0.803 i nche s) and i n 1992 (0.800 i nche s). H owev er , t he t hr ee v a lu e s a re w ith in th e to le ra n c e o f +/- 0.0 1 0 in c h e s d is c u s s e d w ith th e s ta f f. T he appl i cant f ur t her st at ed i n i t s r espo nse t hat t he m i ni m um pr oj ect ed t hi ck ness depend s on whet her t he t r ended d at a i s be f or e or af t er 1992, as d em onst r at ed by cor r osi on t r ends. For l i cense r ene wa l t he u se of cor r osi on r at e t r end s af t er 199 2 i s app r opr i at e be cause of such cor r osi on m i t i gat i ng m easu r es a s r em ov al of t he s and and coa t i ng of t he s hel l. T hen, usi ng cor r osi on r at e t r ends bas ed on 1 992, 1994, and 19 96 UT dat a and t he m i ni m um av er age t hi ck ness m easu r ed i n 1992 (0.800 i nche s), t he m i ni m um pr oj ect ed av er age t hi ck ness t hr ough 2009 an d bey ond r em ai ns a ppr ox i m at el y 0.800 i nche s. T he pr oj ect ed m i ni m um t hi ck ness dur i ng and t hr ough t he per i od of ex t ended o per at i on wi l l be r eev al uat ed af t er U T i nspe ct i ons cond uct ed p ri o r to th e p e ri o d o f e x te n d e d o p e ra ti o n a n d a fte r U T i n s p e c ti o n s e v e ry 1 0 y e a rs th e re a fte r.T he appl i cant f ur t her st at ed i n i t s r espo nse t hat t he engi neer i ng anal y si s t hat dem onst r at ed com pl i ance wi t h AS M E C ode r equi r em ent s ha d t wo par t s, st r ess and s t abi l i t y anal y si s wi t h sa nd a n d s tre s s a n d s ta b il ity a n a ly s e s w ith o u t s a n d. T h e a n a ly s e s a re d o c u m e n te d in G E R e p o rts I ndex N o. 9-1, 9-2, 9-3, and 9-4 t r ansm i t t ed t o t he s t af f i n D ecem ber 1990 a nd i n 1991, r espe ct i v el y. I ndex N os. 9-3 and 9-4 wer e r ev i sed l at er t o co r r ect er r or s i dent i f i ed dur i ng an i nt er nal audi t and r esub m i t t ed t o t he s t af f i n Ja nuar y 1992.T h e s ta f f re q u e s te d th a t th e a p p li c a n t p ro v id e in f o rm a tio n re la te d to th e e v a lu a tio n o f th e re s u lts of t he nex t U T i nspe ct i on of t he s and bed r egi on. I n i t s r espo nse, t he appl i cant st at ed t hat t he new se t of U T m easu r em ent s f or t he f or m er san d bed r egi on wi l l be ana l y z ed by t he s am e m et hodol ogy use d t o anal y z e t he 1992 , 1994, and 19 96 UT dat a. T he r esul t s wi l l t hen be com par ed t o t he 1992 , 1994, and 19 96 UT r esul t s t o co nf i r m t he pr ev i ous no c or r osi on t r end.B e c a u s e o f s u r f a c e r o u g h n e s s o f t h e e x t e r i o r o f t h e d r y w e l l s h e l l , e x p e r i e n c e s h o w s t h a t UT m easu r em ent s c an v ar y si gni f i cant l y unl ess t he UT i nst r um ent i s po si t i oned on t he ex act poi nt as fo r th e p re v i o u s m e a s u re m e n ts. T h u s , a c c e p ta n c e c ri te ri a w i l l b e b a s e d o n th e s ta n d a rd dev i at i on of t he pr ev i ous dat a (+/-11 m i l s) and i nst r um ent acc ur acy of (+/-10 m i l s) f or a t ot al of 21 m i l s. D ev i at i on f r om t hi s v al ue wi l l be c onsi der ed unex pect ed and r equi r i ng c or r ect i v e ac t i ons d e s c rib e d p re v io u s ly. T he s t af f's r ev i ew of t hi s i nf or m at i on i s i n i t s ev al uat i on of t he dr y wel l degr adat i on i ss ue pr esen t ed at t he end of t hi s s ect i on.
Pi t t i n g Co r r o s i o n o f t h e Su p p r e s s i o n Ch a m b e r (To r u s). I n r e v i e w i n g i n f o r m a t i o n i n t h e ASM E Sect i on XI , Subsec t i on I W E P r ogr am di sc uss i on of oper at i ng ex per i ence f or t he s uppr ess i on c h a m b e r (to ru s) a n d v e n t s ys te m , th e s ta f f n o te d th a t th e a p p li c a n t h a d s ta te d th a t th e c o a tin g is i nspe ct ed ev er y out age and r epai r ed, as r equi r ed, t o pr ot ect t he t or us s hel l and t he v ent sy st em f r om cor r osi on. T he s t af f r ef er r ed t o t he Pr ot ect i v e C oat i ng Moni t or i ng and M ai nt enanc e Pr ogr am f or add i t i ona l det ai l s. T he st af f r evi ew ed t he P r ot ect i v e C oat i ng M oni t or i ng a nd M ai nt ena nce Pr ogr am and no t ed t hat , under oper at i ng ex per i ence , t he appl i cant st at ed t hat t or us a nd v ent 3-122 header v apor spa ce Ser v i ce L ev el I coa t i ng i nspe ct i ons i n 2002 f ound t he c oat i ng i n t hese ar eas in g o o d c o n d iti o n. In s p e c tio n o f th e im m e rs e d c o a tin g in th e to ru s f o u n d b li s te rin g th a t p rim a rily i n th e s h e l l i n v e rt b u t a l s o o n th e u p p e r s h e l l n e a r th e w a te r l i n e. T h e m a j o ri ty o f th e b l i s te rs r em ai ned i nt act and c ont i nued t o pr ot ect t he bas e m et al. H owev er , sev er al ar eas i ncl uded pi t t i ng dam age wher e t he bl i st er s wer e f r act ur ed. A qual i t at i v e as ses sm ent of t he pi t s c oncl uded t hat t he pi t dept hs wer e si gni f i cant l y l ess t han t he es t abl i shed acc ept ance cr i t er i a. T he f r act ur ed b l i s te rs w e re re p a i re d to re e s ta b l i s h th e p ro te c ti v e c o a ti n g b a rri e r.T o cl ar i f y , t he s t af f ask ed t he appl i cant f or i nf or m at i on per t ai ni ng t o oper at i ng ex per i ence and li c e n s e re n e w a l a g in g m a n a g e m e n t fo r th e s u p p re s s io n c h a m b e r (to ru s) a n d v e n t s ys te m. In its r espo nse, t he appl i cant st at ed t hat i nspe ct i on of t he s uppr ess i on c ham ber (t or us) and v ent sy st em coa t i ng i s by di v er s ev er y ot her out age i n ac cor danc e wi t h Engi neer i ng Speci f i cat i on SP-1302-52-120, whi ch p r ov i des i nspe ct i on and acc ept ance cr i t er i a f or t he c oat i ng and f or pi t t i ng as a con t i ngenc y i n t he ev ent f ai l ur e of t he c oat i ng r esul t s i n pi t t i ng. T he c oat i ng i s m oni t or ed f or c r a c k s , s a g s , r u n s , fl a k i n g , b l i s t e r s , b u b b l e s , a n d o t h e r d e fec t s d e s c r i b e d i n t h e P r o t e c t i ve C o a t i n g M o n i t o r i n g a n d M a i n t e n a n c e P r o g r a m.T he appl i cant f ur t her st at ed t hat t he s peci f i cat i on r equi r es i nspe ct i on of t he t or us a nd v ent s ys te m s u rf a c e s f o r c o a tin g in te g rity. I f p itti n g is o b s e rv e d is o la te d p its o f 0.1 2 5 in c h e s in di am et er hav e an al l owed m ax i m um dept h of 0.261 i nche s an y wher e i n t he s hel l pr ov i ded t he cent er-t o-cent er di st ance bet ween t he s ubj ect pi t s an d nei ghbor i ng i sol at ed pi t s or ar eas of pi t t i ng co r r osi on i s gr eat er t han 20 i nche s. M ul t i pl e pi t s t hat can b e en com passe d by a 2.5-i nch di am et er ci r cl e ar e l i m i t ed t o a m ax i m um dept h of 0.141 i nche s pr ov i ded t he c ent er-t o-cent er di st ance bet ween t he s ubj ect pi t t ed ar ea and nei ghbor i ng i sol at ed pi t s or ar eas of pi t t i ng cor r osi on i s gr eat er t han 20 i nche s.Pl ant doc um ent at i on t hat des cr i bes t he bl i st er i ng and pi t t i ng and qual i t at i v e as ses sm ent p e rf o rm e d , th e e s ta b li s h e d a c c e p ta n c e c rite ria , a n d c o rre c tiv e a c tio n s ta k e n is in c lu d e d in PB D-AM P-B.1.27.O n Apr i l 19, 2006, t he appl i cant sup pl em ent ed i t s r espo nse t o i ncl ude t he s t at em ent "Pi t s gr eat er th a t 0.0 4 0 in c h e s in d e p th s h a ll b e d o c u m e n te d a n d s u b m itte d to e n g in e e rin g f o r e v a lu a tio n."T he appl i cant f ur t her st at ed i n i t s r espo nse t hat t he t or us a nd v ent sy st em coa t i ng i s c l ass i f i ed S er v i ce Le v el I coat i ng a s descr i bed i n t he P r ot ect i v e C oat i ng M oni t or i ng a nd M ai nt ena nce P r o g r a m. T h e p r o g r a m w a s e va l u a t e d a g a i n s t t h e 1 0 e l e m e n t s o f G A L L A M P X I.S 8 , "P r o t e c t i ve C oat i ng Moni t or i ng and M ai nt enanc e Pr ogr am" and f ound c onsi st ent wi t hout enhanc em ent s or ex cept i ons. Accept ance cr i t er i a ar e ev al uat ed i n el em ent 3.6 of t he Pr ot ect i v e C oat i ng Moni t or i ng and Mai nt enanc e Pr ogr am (PB D-AM P-B.1.33). T he i nspe ct i on i s pe r f or m ed by AS M E S ect i on XI L e v e l II a n d L e v e l III i n s p e c to rs. A c c e p ta n c e c rite ria f o r p its a re b a s e d o n e n g in e e rin g a n a ly s is t hat use s t he m et hod of AS M E C ode Case N-597 as gui danc e f or cal cul at i on of pi t dept hs t hat wi l l not v i ol at e t he l ocal st r ess r equi r em ent s of ei t her AS M E C ode Sect i on I I I , 1977 Edi t i on or S e c tio n V III, 1 9 6 2 E d iti o n. T he appl i cant al so s t at ed i n i t s r espo nse t hat t he i nspe ct i on t hat di sc ov er ed t he bl i st er i ng was c o n d u c te d u n d e r th e p ro te c ti v e c o a ti n g m o n i to ri n g a n d m a i n te n a n c e p ro g ra m. E x a m i n a ti o n s a re p e rf o rm e d b y A S M E S e c tio n X I L e v e l II a n d L e v e l III i n s p e c to rs. T h e a p p li c a n t fu rth e r s ta te d in i t s r espo nse t hat bot h t he AS M E S ect i on XI , Subsec t i on I W E and t he Pr ot ect i v e C oat i ng M oni t or i ng and M ai nt enanc e Pr ogr am s ar e cr edi t ed t o m anage l oss of m at er i al due t o co r r osi on f or t he s uppr ess i on c ham ber (t or us) and t he v ent sy st em f or t he per i od of ex t ended o per at i on.
3-123 O n Apr i l 19, 2006, t he appl i cant sup pl em ent ed i t s r espo nse t o cl ar i f y t hat dur i ng t he per i od of ext end ed o per at i on, t or us coa t i ng i nspe ct i on w i l l be p er f or m ed i n al l 20 t or us ba y s at a f r equ ency of ev er y ot her r ef uel i ng out age f or t he c ur r ent coa t i ng s y st em. Shoul d t he c oat i ng s y st em be r epl aced , t he i nspe ct i on f r equenc y and s cope wi l l be r e-ev al uat ed. T he i nspe ct i on s cope wi l l , as a m i ni m um , m eet t he r equi r em ent s of AS M E C ode Subsec t i on I W E. T hi s s peci f i c c om m i t m ent (C om m i t m ent N o. 33) i s associ at ed w i t h t he P r ot ect i v e C oat i ng M oni t or i ng a nd M ai nt ena nce P r o g r a m.I n i t s l e t t e r d a t e d Ma y 1 , 2 0 0 6 , t h e a p p l i c a n t c o m m i t t e d (Co m m i t m e n t No. 2 7) t o t h e f o l l o w i n g: As not ed i n t he appl i cant's Apr i l 4, 2006 l et t er t o N R C , O C G S wi l l per f or m t or us c oat i ng i nspe ct i ons in a c c o rd a n c e w ith A S M E C o d e S e c tio n X I, S u b s e c tio n IW E e v e ry o th e r re f u e li n g o u ta g e p rio r to and dur i ng t he per i od of ex t ended o per at i on. T hi s ne w com m i t m ent cl ar i f i es t hat t he s cope of each of t hese i nspe ct i ons wi l l i ncl ude t he wet t ed ar ea of al l 20 t or us b ay s. Shoul d t he c ur r ent t or us c oat i ng s y st em be r epl aced , t he i nspe ct i on f r equenc y and s cope wi l l be r e-ev al uat ed.In s p e c tio n s c o p e w il l, a s a m in im u m , m e e t th e re q u ire m e n ts o f A S M E C o d e S e c tio n X I, S u b s e c tio n IW E. O n A p ri l 1 9 , 2 0 0 6 , t h e a p p l i c a n t s u p p l e m e n te d i ts re s p o n s e , s ta ti n g th a t C o n d i ti o n R e p o rt N o. 373695 ass i gnm ent s 2 a nd 3 ha v e been i ni t i at ed t o dr i v e pr ogr am i m pr ov em ent s f or t he m oni t or i ng and t r endi ng of t or us d esi gn m ar gi ns, and t o dev el op r ef i ned ac cept ance cr i t er i a and t hr esho l ds f or ent er i ng c oat i ng def ect s an d unac cept abl e pi t dept hs i nt o t he c or r ect i v e ac t i on pr oces s f or f ur t her ev al uat i on. T hese i m pr ov em ent s wi l l be i ncor por at ed i nt o t he i nspe ct i on i m pl em ent i ng doc um ent s pr i or t o t he nex t per f or m ance of t hese i nspe ct i ons, whi ch i s al so p r i or t o t he per i od of ex t ended o per at i on. T hese i m pr ov em ent s wi l l be des cr i bed i n a l et t er t o t he N R C. In its le tte r d a te d M a y 1 , 2 0 0 6 , th e a p p li c a n t s ta te d th a t it w il l d e v e lo p re f in e d a c c e p ta n c e c rite ria a n d t h r e s h o l d s for e n t e r i n g t o r u s c o a t i n g d e fec t s a n d u n a c c e p t a b l e p i t d e p t h s i n t o t h e c o r r e c t i ve act i on pr oces s f or f ur t her ev al uat i on. T hese i m pr ov em ent s wi l l be i ncor por at ed i nt o t he in s p e c tio n im p le m e n tin g d o c u m e n ts p rio r to th e n e x t p e rf o rm a n c e o f th e s e in s p e c tio n s , w h ic h is al so p r i or t o t he per i od of ex t ended o per at i on.T he s t af f f i nds t hi s ac cept abl e si nce i t wi l l pr ov i de addi t i onal cr i t er i a t o det er m i ne whet her d e g ra d a tio n o f th e s u p p re s s io n c h a m b e r is b e in g a d e q u a te ly m a n a g e d. O n Apr i l 19, 2006, t he appl i cant sup pl em ent ed i t s r espo nse, st at i ng t hat t he ans wer s pr ov i ded p re v io u s ly o n to ru s w a ll th ic k n e s s w e re w ritte n to a d d re s s s p e c ific c o n c e rn s o f th e A M P a u d it te a m a n d w e re c e n te re d a ro u n d w o rs e c a s e to ru s th ic k n e s s m a rg in s e x is tin g o n th e to ru s s h e ll d u e to c o rro s io n. T h is s u p p le m e n ta l i n f o rm a tio n is b e in g p ro v id e d to re in f o rc e th a t, b a s e d o n a ll av ai l abl e i nspe ct i on r esul t s, t he av er age t hi ck ness of t he t or us r em ai ns a t 0.385 i nche s. Based on t he r esul t s of t he i nspe ct i ons per f or m ed t hr ough 19 93 (14R), i t was c oncl uded t hat t he t or us s h e ll th ic k n e s s h a d re m a in e d v irtu a ll y u n c h a n g e d f o ll o w in g th e re p a ir a n d re c o a tin g e f f o rts per f or m ed i n 1984. T hi s was com m uni cat ed t o t he NR C v i a l et t er C 321-94-2186 da t ed N ov em ber 3, 1994, Am endm ent N o. 177 t o D PR-16 and SE R dat ed Febr uar y 21, 1995 f or t he el ect r om at i c r el i ef v al v e (EM R V) t echn i cal spe ci f i cat i on c hange. C oat i ng i nspe ct i ons per f or m ed subs equent t o 1993 (14R) con t i nue t o co nf i r m t hat t he t or us s hel l t hi ck ness has r em ai ned v i r t ual l y unc hanged f ol l owi ng t he r epai r and r ecoa t i ng ef f or t s pe r f or m ed i n 1984, and t hat t he av er age t hi ck ness of t he t or us r em ai ns a t 0.385 i nche s. T or us i nt egr i t y wi l l con t i nue t o be ev al uat ed dur i ng f ut ur e i nspe ct i ons (per f or m ed ev er y ot her r ef uel i ng out age) i nt o t he per i od of ex t ended o per at i on.
3-124 T h e a p p li c a n t a ls o c la rif ie d th e e x te n t o f p itti n g c o rro s io n. P itti n g c o rro s io n le s s th a n o r e q u a l to 0.040 i nche s was not r epai r ed dur i ng t he 1984 t or us r epai r and r ecoa t i ng ef f or t bas ed on av ai l abl e m ar gi ns a nd was f ound t o be ac cept abl e wi t hout any si z e r est r i ct i on s i nce i t sat i sf i ed m i n i m u m u n i form t h i c k n e s s r e q u i r e m e n t s. I n s p e c t i o n a c t i vi t i e s s u b s e q u e n t t o 1 9 8 4 h a ve i dent i f i ed 5 i sol at ed pi t s t hat ex ceed 0.040 i nche s. T he f ol l owi ng ar eas hav e been m apped f or t r endi ng and anal y si s du r i ng f ut ur e i nspe ct i ons: 1 pi t of 0.042 i nche s i n bay 1; 1 pi t of 0.0 6 8 5 in c h e s in b a y 2; 2 p its o f 0.0 5 0 in c h e s in b a y 6; 1 p it o f 0.0 5 8 in c h e s in b a y 1 0. S h e ll t hi ck ness es h av e been ev al uat ed agai nst cod e r equi r em ent s an d f ound t o sa t i sf y al l des i gn and l i c e n s i n g b a s i s r e q u i r e m e n t s. T h e r e fore , t h e i n t e g r i t y o f t h e t o r u s s h e l l h a s b e e n ve r i fi e d t o h a ve adequa t e sh el l t hi ck ness m ar gi ns t o ens ur e des i gn and l i cens i ng bas i s r equi r em ent s c an be m ai nt ai ned.T he appl i cant al so s uppl em ent ed i t s r espo nse t o i ncl ude t he s t at em ent , "Pi t s gr eat er t hat 0.0 4 0 in c h e s in d e p th s h a ll b e d o c u m e n te d a n d s u b m itte d to e n g in e e rin g f o r e v a lu a tio n."T he s t af f r ev i ewed t he appl i cant's r espo nse and det er m i ned t hat i t was r espo nsi v e t o t he ques t i ons ask ed.I n r e v i e w i n g P B D-A M P-B.1.2 7 f o r t h e a p p l i c a n t's A S M E S e c t i o n X I , S u b s e c t i o n I W E P r o g r a m, th e s ta f f n o te d th a t, in th e d is c u s s io n o f to ru s d e g ra d a tio n p a g e s 2 5 to 3 1 o f th is d o c u m e n t s ta te th a t,I nspe ct i ons per f or m ed i n 2002 f ound t he c oat i ng t o be i n good cond i t i on i n t he v apor ar ea of t he t or us a nd v ent header , and i n f ai r con di t i on i n i m m er si on.C oat i ng def i ci enci es i n i m m er si on i ncl ude bl i st er i ng, r andom and m echa ni cal dam age. Bl i st er i ng oc cur s pr i m ar i l y i n t he s hel l i nv er t but was a l so n ot ed on t he upp er shel l nea r t he w at er l i ne. T he f r act ur ed b l i st er s we r e r epa i r ed t o r eest abl i sh t he pr ot ect i v e co at i ng bar r i er. T hi s i s an ot her ex am pl e of obj ect i v e ev i denc e t hat t he AS M E S ect i on XI , Subsec t i on I W E P r ogr am can i dent i f y degr adat i on and i m pl em ent cor r ect i v e ac t i ons t o pr ev ent t he l oss of t he c ont ai nm ent's i nt ended f u n c tio n. W h il e b li s te rin g is c o n s id e re d a d e f ic ie n c y, i t is s ig n ific a n t o n ly w h e n it i s f r act ur ed and ex pose s t he bas e m et al t o co r r osi on at t ack. T he m aj or i t y of t he bl i st er s r em ai n i nt act and c ont i nue t o pr ot ect t he bas e m et al; con sequ ent l y t he cor r osi on r at es a r e l ow. Q ual i t at i v e as ses sm ent of t he i dent i f i ed pi t s i ndi cat e t hat th e m e a s u re d p it d e p th s (5 0 m il s m a x im u m) a re s ig n ific a n tly le s s th a n th e c rite ria est abl i shed i n sp eci f i cat i on SP-1302-52-120 (141- 261 m i l s, depend i ng on d i a m e te r o f th e p i t a n d s p a c i n g b e tw e e n p i ts).T h e s ta f f a s k e d th e a p p li c a n t to c o n f irm o r c la rif y th a t (1) o n ly th e f ra c tu re d b li s te rs f o u n d in th is i nspe ct i on wer e r epai r ed, (2) pi t s wer e i dent i f i ed wher e t he bl i st er s wer e f r act ur ed, (3) pi t dept hs wer e m easu r ed and f ound t o 50 m i l s m ax i m um , (4) t he i nspe ct i on Speci f i cat i on SP-1302-52-120 i ncl udes pi t-dept h ac cept ance cr i t er i a f or r api d ev al uat i on of obs er v ed pi t t i ng, and (5) t he m in im u m p it d e p th o f c o n c e rn is 1 4 1 m il s (0.1 4 1 in c h e s) a n d p its a s d e e p a s 2 6 1 m il s (0.261 i nche s) m ay be ac cept abl e.I n i t s r espo nse, t he appl i cant st at ed t hat Speci f i cat i on SP-1302-52-120, "Speci f i cat i on f or In s p e c tio n a n d L o c a li ze d R e p a ir o f th e T o ru s a n d V e n t S ys te m C o a tin g ," s p e c ifie s re p a ir r equi r em ent s f or coa t i ng def ect s ex posi ng s ubst r at e and f r act ur ed bl i st er s s howi ng s i gns of c o rro s io n. T h e re p a irs to w h ic h th e in s p e c tio n re p o rt re f e rre d in c lu d e d f ra c tu re d b li s te rs a s w e ll as a ny m echa ni cal l y dam aged ar eas whi ch h av e ex pose d bar e m et al sho wi ng s i gns of cor r osi on.T her ef or e, onl y f r act ur ed bl i st er s wi l l be c andi dat es f or r epai r , not bl i st er s t hat r em ai n i nt act. T he 3-125 num ber and l ocat i on of r epai r s ar e t abul at ed i n t he f i nal i nspe ct i on r epor t pr epar ed by U nder wat er C onst r uct i on Cor por at i on.T he appl i cant f ur t her st at ed i n i t s r espo nse t hat coa t i ng def i ci enci es i n t he i m m er si on r egi on i n c l u d e d b l i s te ri n g w i th m i n o r m e c h a n i c a l d a m a g e. B l i s te ri n g o c c u rre d p ri m a ri l y i n th e s h e l l i n v e rt b u t w a s a l s o n o te d o n th e u p p e r s h e l l n e a r th e w a te r l i n e. M o s t b l i s te rs w e re i n ta c t. In ta c t b l i s te rs wer e ex am i ned by r em ov i ng t he bl i st er cap ex posi ng t he s ubst r at e. C or r osi on at t ack under non-f r act ur ed bl i st er s was m i ni m al and ge ner al l y l i m i t ed t o su r f ace di sc ol or at i on. Ex am i nat i on of t he su bst r at e r eveal ed sl i ght di scol or at i on a nd p i t t i ng w i t h pi t dep t hs l ess t han 0.001 i nche s.Sev er al bl i st er ed ar eas i ncl uded pi t t i ng c or r osi on wher e t he bl i st er s wer e f r act ur ed. T he subs t r at e benea t h f r act ur ed bl i st er s ge ner al l y ex hi bi t ed a s l i ght l y heav i er m agnet i t e ox i de l ay er and m i nor pi t t i ng (l ess t han 0.010 i nche s) of t he s ubst r at e.I n addi t i on t o bl i st er i ng, r andom def i ci enci es t hat ex pose d bas e m et al wer e i dent i f i ed i n t he t or us i m m er si on r egi on c oat i ng (e.g., m i nor m echa ni cal dam age) dur i ng t he 19R (2002) t or us c oat i ng i nspe ct i ons. T hey r anged i n si z e f r om 1/16 t o 1/2 i nche s i n di am et er. Pi t t i ng i n t hese ar eas was qual i t at i v el y ev al uat ed and r anged f r om l ess t han 10 m i l s t o sl i ght l y m or e t han 40 m i l s i n a f ew i sol at ed c ases. T hr ee quan t i t at i v e pi t dept h m easu r em ent s wer e t aken i n se v er al l ocat i ons i n t he i m m e rs i o n a re a o f B a y 1. P i t d e p th s a t t h e s e s i te s ra n g e d fro m 0.0 0 8 to 0.0 4 2 i n c h e s a n d w e re j udged t o be r epr esen t at i v e of t y pi cal con di t i ons f ound on t he s hel l. Pr i or t o t he 2002 i nspe ct i on, 4 p i ts g re a te r th a n 0.0 4 0 i n c h e s w e re i d e n ti fie d. T h e p i t d e p th s w e re 0.0 5 8 i n c h e s (1 p i t i n 1 9 8 8), 0.05 i nche s (2 pi t s i n 19 91), and 0.068 5 i nche s (1 pi t i n 19 92). T he p i t s we r e eval uat ed a gai nst t he l ocal pi t dept h ac cept ance cr i t er i a and f ound ac cept abl e.T he appl i cant al so s t at ed t hat t he ac cept ance cr i t er i a f or pi t dept h ar e as f ol l ow: I sol at ed pi t s of 0.1 2 5 in c h e s in d ia m e te r h a v e a n a ll o w e d m a x im u m d e p th o f 0.2 6 1 in c h e s a n yw h e re in th e s h e ll pr ov i ded t he c ent er-t o-cent er di st ance bet ween t he s ubj ect pi t and ne i ghbor i ng i sol at ed pi t s or ar eas of pi t t i ng c or r osi on i s gr eat er t han 20.0 i nche s. T hi s c r i t er i on i ncl udes ol d pi t s or ol d ar eas o f p itt in g c o r r o s io n th a t h a v e b e e n f ille d o r re-c o a te d. M u ltip le p its th a t c a n b e e n c o m p a s s e d b y a 2-1/2 i nche s di am et er ci r cl e sh al l be l i m i t ed t o a m ax i m um pi t dept h of 0.141 i nche s pr ov i ded t he cent er-t o-cent er di st ance bet ween t he s ubj ect pi t t ed ar ea and nei ghbor i ng i sol at ed pi t s or ar eas of pi t t i ng c or r osi on i s gr eat er t han 20.0 i nche s. T hi s c r i t er i on i ncl udes ol d pi t s or ol d ar eas of pi t t i ng c or r osi on t hat hav e been f i l l ed or r e-coat ed.D r y wel l D egr adat i on I ss ue. T he s t af f ev al uat ed t he appl i cant's r ev i sed agi ng m anagem ent com m i t m ent s t o addr ess f our di st i nct i ss ues: (1) m oni t or i ng/el i m i nat i ng wat er l eaka ge, (2)cor r osi on i n t he uppe r dr y wel l r egi on, (3) cor r osi on i n t he f or m er san d bed r egi on, and (4) pi t t i ng c o rro s io n in th e s u p p re s s io n c h a m b e r (to ru s). T h e s ta f f's e v a lu a tio n o f e a c h a re a is d is c u s s e d in t he f ol l ow i ng p ar agr aph s. (1)
M o n ito rin g/E li m in a tin g W a te r L e a k a g e in th e G a p B e tw e e n th e D ryw e ll a n d S h ie ld W a ll.T he appl i cant m ade a c om m i t m ent (C om m i t m ent N o. 27), t o co nt i nue t he us e of t he st r i ppabl e co at i ng f or eac h r ef uel i ng dur i ng t he l i cens e r enewal per i od. Accor di ng t o t he appl i cant , t hi s c oat i ng has been e f f ect i v e i n el i m i nat i ng wat er i nt r usi on i nt o t he annu l ar spac e bet ween t he dr y wel l she l l and t he c oncr et e sh i el d wal l. I n t he LRA , t he appl i cant had not com m i t t ed t o co nt i nue i t s us e.T he appl i cant al so c om m i t t ed (C om m i t m ent N o. 27) t o i nv est i gat e t he s our ce o f l eaka ge, ta k e c o rre c ti v e a c ti o n s , e v a l u a te th e i m p a c t o f th e l e a k a g e a n d , i f n e c e s s a ry , p e rfo rm addi t i onal dr y wel l i nspe ct i ons i n t he ev ent wat er l eaka ge f r om t he f or m er san d bed r egi on 3-126 i s f o u n d d u r i n g t h e p e r i o d o f e x t e n d e d o p e r a t i o n. Un d e r t h e c u r r e n t l i c e n s e t e r m, OCGS is c o m m itte d to m o n ito r th e f o rm e r s a n d b e d re g io n d ra in s f o r w a te r le a k a g e. T h is c o m m i t m e n t w a s n o t p r e v i o u s l y i d e n t i f i e d i n t h e L RA.T he s t af f not ed t hat whi l e t hese new c om m i t m ent s ad dr ess bot h m i t i gat i on of and m o n ito rin g f o r w a te r le a k a g e; th e y a re a n e s s e n tia l e le m e n t o f th e a p p li c a n t's o v e ra ll pr ogr am t o m anage a gi ng of t he degr aded dr y wel l dur i ng t he l i cens e r enewal per i od, t he a p p l i c a n t h a s n o t e s t a b l i s h e d a l e a k a g e mo n i t o r i n g p r o g r a m.H owev er , t he appl i cant i ndi cat ed t hat t her e i s no f or m al pr oced ur e i n pl ace t o m oni t or le a k a g e f ro m th e s a n d b e d d ra in s a n d s ta te d , "Is s u e R e p o rt #3 4 8 5 4 5 w a s s u b m itte d in to t he c or r ect i v e ac t i on pr oces s when t hi s was di sc ov er ed. C or r ect i v e ac t i ons hav e been i ni t i at ed t o cr eat e r ecur r i ng ac t i v i t i es c ont r ol l ed wi t h t he wor k m anagem ent pr oces s an d p ro c e d u re s , t o p e rfo rm a l l fu tu re re q u i re d i n s p e c ti o n s to m e e t t h e p re s e n t c o m m i tm e n t." T he s t af f f ound t hat t he abs ence of a l eaka ge m oni t or i ng pr ogr am t o m eet t he c ur r ent l i cens e t er m com m i t m ent r ai ses a ques t i on abou t t he bas i s f or t he appl i cant's c l ai m t hat w a te r is n o lo n g e r le a k in g in to th e a n n u la r g a p b e tw e e n th e d ryw e ll s h e ll a n d th e c o n c re te shi el d wal l. Subsequen t t o t he audi t , i n r espo nse t o R AI 4.7.2-1, by l et t er dat ed J une 20, 2006, t he appl i cant pr ov i ded add i t i onal i nf or m at i on r egar di ng t he AM P and act i v i t i es ass oci at ed wi t h dr y wel l l eaka ge m oni t or i ng pr ogr am. T he s t af f's ev al uat i on of t he appl i cant's ad di t i onal i nf or m at i on and com m i t m ent s i s do cum ent ed i n SE R Sect i on 4.7.2. (2)
U pper D r y wel l R egi on. T he appl i cant m ade a n ew l i cens e r enewal com m i t m ent (C om m i t m ent N o. 27), t o co nt i nue UT m easu r em ent s of t he uppe r dr y wel l r egi on f or t he per i od of ex t ended o per at i on.T he appl i cant m anages l oss of m at er i al due t o co r r osi on i n t he uppe r dr y wel l r egi on (s p h e ric a l a n d c yl in d ric a l s e c tio n s) b y a u g m e n te d e x a m in a tio n s in a c c o rd a n c e w ith I W E-124 0. A n U T sur v ey i s per f or m ed e v er y ot her r ef uel i ng o ut age (4 y ear s) t o de t ect any addi t i onal l oss of m at er i al due t o co r r osi on. T he UT r esul t s ar e ev al uat ed and tre n d e d to e n s u re th a t th e d ryw e ll s h e ll is c a p a b le o f p e rf o rm in g its in te n d e d f u n c tio n to t he end of pl ant l i f e. T he ar eas subj ect t o per i odi c UT m easu r em ent s wer e se l ect ed base d on ex t ensi v e ex pl or at or y t est i ng t o es t abl i sh t he m ost sev er el y cor r oded l ocat i ons i n t h e d r y w e l l a b o v e t h e s a n d b e d r e g i o n. Co r r o s i o n o f t h e u p p e r d r y w e l l r e g i o n i s a TL AA per 10 CF R 54.21(c). T he appl i cant's TLA A i s do cum ent ed i n LRA Sect i on 4.7.2. T he a p p li c a n t im p le m e n ts T L A A o p tio n (iii) a n d u s e s th e U T in s p e c tio n re s u lts f ro m its IW E p ro g ra m to m o n ito r re m a in in g th ic k n e s s , to p e rio d ic a ll y u p d a te th e c o rro s io n ra te , a n d to per i odi cal l y updat e t he pr oj ect ed r em ai ni ng t hi ck ness at t he end of t he l i cens e r enewal p e rio d. T he ev al uat i on of t hi s TLA A i s ad dr ess ed i n SE R Sect i on 4. (3)
For m er Sand Bed R egi on of D r y wel l. I n t he LRA , t he appl i cant's po si t i on was t hat cor r osi on i n t he f or m er san d bed r egi on has been c om pl et el y ar r est ed by t he r em edi al act i ons al r eady t aken. T he or i gi nal LR A com m i t m ent was t o i nspe ct a se ct i on of coa t i ng e v e ry o th e r o u ta g e (4 ye a rs) to c o n f irm its s o u n d n e s s. T h e la s t U T re a d in g s w e re in 1996. As a r esul t of t he audi t , t he appl i cant m ade s ev er al new c om m i t m ent s t o m anage agi ng of t he f or m er san d bed r egi on of t he dr y wel l dur i ng t he per i od of ex t ended oper at i on. I n i t s l et t er s da t ed Apr i l 4, 2006, and May 1, 2006, t he appl i cant r ev i sed t he com m i t m ent s:
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- M oni t or t he pr ot ect i v e co at i ng on t he ex t er i or sur f aces of t he dr y wel l i n t he s and b e d re g io n in a c c o rd a n c e w ith th e re q u ire m e n ts o f A S M E C o d e S e c tio n X I, S u b s e c ti o n IW E d u ri n g th e p e ri o d o f e x te n d e d o p e ra ti o n (C o m m i tm e n t N o. 2 7),
- C ond uct per i odi c U T i nspe ct i on o f t he f or m er sand bed r egi on b ef or e t he l i cense re n e w a l p e ri o d a n d e v e ry 1 0 y e a rs th e re a fte r (C o m m i tm e n t N o. 2 7),
- At t em pt dur i ng t he UT i nspe ct i ons of t he s and bed r egi on pr i or t o t he per i od of ex t ended o per at i on a UT i nspe ct i on f r om t he ex t er i or of t he dr y wel l of som e of t he l o c a l l y th i n n e d a re a s i d e n ti fie d i n th e 1 9 9 2 i n s p e c ti o n (C o m m i tm e n t N o. 2 7),
- I nspe ct t he r em ai ni ng 50 p er cent of t he ex t er nal coa t i ng i n t he f or m er san d bed r egi on bef or e t he l i cens e r enewal per i od (t o dat e, onl y 50 per cent of t hi s c oat i ng has been i nspe ct ed s i nce i t was a ppl i ed i n t he ear l y 1990s) and c onduc t a 100 per cent r e-i nspe ct i on of t he c oat i ng ev er y 10 y ear s du r i ng t he l i cens e r enewal p e ri o d (C o m m i tm e n t N o. 2 7),
- If a d d iti o n a l c o rro s io n o f th e s a n d b e d re g io n is id e n tifie d b y th e U T in s p e c tio n to b e c o n d u c t e d b e fore e n t e r i n g t h e l i c e n s e r e n e w a l p e r i o d , i n i t i a t e c o r r e c t i ve act i ons t hat i ncl ude one or al l of t he f ol l owi ng, depend i ng on t he ex t ent of i dent i f i ed c or r osi on:<P e rf o rm a d d iti o n a l U T m e a s u re m e n ts to c o n f irm th e re a d in g s. <N o tify th e s ta f f w ith in 4 8 h o u rs o f c o n f irm a tio n o f th e id e n tifie d c o n d iti o n. <I nspe ct t he c oat i ngs i n t he s and bed r egi on i n ar eas wher e t he addi t i onal c o rro s io n w a s d e te c te d. <Per f or m an eng i neer i ng ev al uat i on t o as ses s t he ex t ent of t he c ondi t i on a n d to d e te rm i n e w h e th e r a d d i ti o n a l i n s p e c ti o n s a re re q u i re d to a s s u re d ryw e ll in te g rity. <Per f or m an ope r abi l i t y det er m i nat i on and j ust i f i cat i on f or con t i nued o p e ra tio n u n til n e x t s c h e d u le d in s p e c tio n.
T hese act i ons wi l l be c om pl et ed bef or e r est ar t i ng f r om an out age (C om m i t m ent N o. 2 7).T he s t af f not ed t hese new c om m i t m ent s f or m anagi ng agi ng of t he f or m er san d bed r egi on, but al so n ot ed t he v er y sm al l r em ai ni ng m ar gi n bet ween t he m i ni m um r epor t ed uni f or m t hi ckness a nd t he m i ni m um r equ i r ed u ni f or m t hi ckness (0.800 i nche s v s.0.736 i nche s). T hi s ap par ent l ack of m ar gi n l ed t he s t af f t o r eques t addi t i onal i nf or m at i on about (1) t he UT i nspe ct i on r esul t s an d dat a r educ t i on m et hods em pl oy ed t o det er m i ne th e m in im u m re m a in in g th ic k n e s s a n d (2) th e a n a ly tic a l m e th o d o lo g y e m p lo ye d to det er m i ne t he m i ni m um r equi r ed t hi ck ness f or l ocal i z ed ar eas wher e t he m easu r ed t hi ck ness i s l ess t han t he m i ni m um r equi r ed uni f or m t hi ck ness. T he appl i cant pr ov i ded addi t i onal i nf or m at i on on t hese sub j ect s. D ur i ng a f ol l owup ons i t e audi t con duct ed A p ril 1 9-2 0 , 2 0 0 6 , th e s ta f f d is c u s s e d th e s e re s p o n s e s w ith th e a p p li c a n t in d e ta il to ensu r e a c om pl et e under st andi ng.T he s t af f r ev i ewed t he det ai l ed UT t hi ck ness r eadi ngs i n t he s and bed r egi on t aken f r om t he i nsi de s ur f ace t hr ough 19 96 and on t he out si de s ur f ace i n 1992. T he s t af f poi nt ed out a def i ni t e bi as i n t he 1996 r eadi ngs beca use t he av er age t hi ck ness (base d on 49 re a d in g s/lo c a tio n) in c re a s e d a t a lm o s t a ll lo c a tio n s. T h e s ta f f a n d th e a p p li c a n t's per sonn el di sc uss ed pos si bl e ca uses f or t hi s bi as, but no c oncl usi ons coul d be dr awn.
3-128T he s t af f's r ev i ew of t he UT dat a co nf i r m ed t hat t he r em ai ni ng t hi ck ness i n t he f or m er sand bed r egi on s i gni f i cant l y ex ceed s t he m i ni m um r equi r ed t hi ck ness of 0.736 i nche s at m ost m oni t or ed l ocat i ons. Sev er al l ocat i ons ar e cl ose t o t he or i gi nal des i gn t hi ck ness of 1.154 i nche s. H owev er , i n a f ew v er y l ocal i z ed ar eas, pr i m ar i l y i n Bay s 1 a nd 13, r em ai ni ng t hi ck ness es l ess t han 0.736 i nche s ha v e been m easu r ed.T h e s ta f f a ls o re v ie w e d th e te c h n ic a l b a s is d o c u m e n ts th a t e s ta b li s h e d c o m p li a n c e w ith AS M E C ode r equi r em ent s. I n r espo nse t o a que st i on, t he appl i cant st at ed t hat t he engi neer i ng anal y si s de m onst r at i ng c om pl i ance wi t h AS M E C ode r equi r em ent s was per f or m ed i n t wo par t s, st r ess and s t abi l i t y anal y si s wi t h and wi t hout san d. T he anal y ses a re d o c u m e n te d in G E R e p o rts In d e x N o. 9-1 , 9-2 , 9-3 , a n d 9-4 tra n s m itte d to th e N R C in D e c e m b e r 1 9 9 0 a n d in 1 9 9 1 , re s p e c tiv e ly. In d e x N o s. 9-3 a n d 9-4 w e re re v is e d la te r to c o rre c t e rro rs id e n tifie d d u rin g a n in te rn a l a u d it, a n d w e re re s u b m itte d to th e s ta f f in Janu ar y 1992.T he appl i cant st at ed t hat t he dr y wel l she l l t hi ck ness i n t he s and bed r egi on i s ba sed on st abi l i t y anal y si s wi t hout san d (G E R epor t 9-4). T he anal y si s i s ba sed on a 36-degr ee sec t i on m odel t hat t akes adv ant age of sy m m et r y of t he dr y wel l wi t h 10 v ent s. T he m odel i ncl udes t he dr y wel l she l l f r om t he bas e of t he s and bed r egi on t o t he t op of el l i pt i cal head and t he v ent and v ent header. T he t or us i s no t i ncl uded i n t hi s m odel bec ause t he bel l ows pr ov i de a v er y f l ex i bl e co nnec t i on whi ch d oes not al l ow si gni f i cant st r uct ur al i nt er act i on bet ween t he dr y wel l and t he t or us. T he anal y si s c onse r v at i v el y ass um ed t hat t he s hel l t hi ck ness i n t he ent i r e sa nd bed r egi on had been r educ ed uni f or m l y t o a t hi ckness o f 0.736 i nche s.T he appl i cant f ur t her i ndi cat ed t hat G E Let t er R epor t "Sand Bed Local T hi nni ng and R ai si ng t he Fi x i t y H ei ght Anal y si s" pr esen t s r esul t s de m onst r at i ng t hat ass um i ng a u n ifo rm re d u c tio n in th ic k n e s s o f 2 7 p e rc e n t to 0.5 3 6 in c h e s o v e r a 1 f t a re a w il l c re a te 2 onl y a 9.5 per cent r educ t i on i n t he l oad f act or and t heor et i cal buc kl i ng s t r ess f or t he w h o le d ryw e ll. A s e c o n d b u c k li n g a n a ly s is a s s u m in g a w a ll th ic k n e s s re d u c tio n o f 1 3.5 per cent t o 0.636 i nche s ov er a 1 f t ar ea r educ ed t he l oad f act or and t heor et i cal buc kl i ng 2 s tre s s b y o n ly 3.5 p e rc e n t fo r th e w h o le d ryw e ll. T he appl i cant f ur t her st at ed t hat t o br i ng t hese r esul t s i nt o per spec t i v e, a r ev i ew of t he N D E re p o rts in d ic a te s th e re a re 2 0 U T m e a s u re d a re a s in th e w h o le s a n d b e d re g io n w ith t hi ck ness es l ess t han 0.736 i nche s c ov er i ng a c onse r v at i v e t ot al ar ea of 0.68 f t of t he 2 d ryw e ll s u rf a c e w ith a n a v e ra g e th ic k n e s s o f 0.7 0 3 in c h e s o r 4.5 p e rc e n t re d u c tio n in w a ll t hi ckness. Fu r t her m or e, al l of t hese v er y l ocal wa l l ar eas a r e cen t er ed a bou t t he vent s, s ig n ific a n tly s tiff e n in g th e s h e ll. T h is s tiff e n in g e f f e c t li m its th e s h e ll b u c k li n g in th e s h e ll sand bed r egi on t o t he m i dpo i nt bet we en t wo v ent s.T he s t af f r ev i ewed t he det ai l ed UT t hi ck ness r eadi ngs, t he G E st abi l i t y anal y ses , and t he cons er v at i v e as sum pt i ons used i n t he G E Let t er R epor t , "Sand Bed Local T hi nni ng and R ai si ng t he Fi x i t y H ei ght Anal y si s." T he s t af f con cl udes t hat t he degr aded c ondi t i on of t he f o rm e r s a n d b e d re g io n o f th e d ryw e ll s h e ll m e a s u re d in 1 9 9 6 w a s a d e q u a te f o r its in te n d e d f u n c tio n in a c c o rd a n c e w ith its d e s ig n b a s is. H owev er , bec ause t her e has been n o U T i nspe ct i on c onduc t ed s i nce 1996 an d t he r em ai ni ng c or r osi on m ar gi n i n 1996 was l ess t han 0.1 i nche s at sev er al l ocat i ons, t he s t a f f i n i t i a t e d f u r t h e r e v a l u a t i o n o f t h e a p p l i c a n t's a g i n g ma n a g e me n t c o mmi t me n t f o r UT 3-129i nspe ct i on of t he f or m er san d bed r egi on.T h e a p p li c a n t c re d ite d its P ro te c tiv e C o a tin g M o n ito rin g a n d M a in te n a n c e P ro g ra m to m oni t or/m ai nt ai n t he pr ot ect i v e co at i ng on t he ex t er i or sur f ace of t he dr y wel l i n t he f or m er s a n d b e d re g i o n. T h e s t a ff e va l u a t e d t h i s p ro g ra m i n S E R S e c t i o n 3.0.3.2.2 7. T h e s t a ff f i nds t he enha ncem ent t o t he pr ot ect i v e co at i ng m oni t or i ng and m ai nt enanc e pr ogr am a c c e p ta b le b e c a u s e it e n s u re s th a t th e re q u ire m e n ts o f A S M E C o d e IW E re la te d to coat i ng i nspe ct i on wi l l be i m pl em ent ed dur i ng t he per i od of ex t ended o per at i on. T he a p p li c a n t's re v is e d a g in g m a n a g e m e n t c o m m itm e n t (C o m m itm e n t N o. 2 7) is to c o m p le te a 100 p er cent i nspe ct i on of t he c oat i ng (i ni t i at ed i n 1994 and c ur r ent l y 50 per cent com pl et e) pr i or t o t he l i cens e r enewal per i od and t o co nduc t sub sequ ent 100 pe r cent r ei nspe ct i ons ev er y 10 y ear s du r i ng t he l i cens e r enewal per i od.Because of t he m i ni m al cor r osi on m ar gi n r em ai ni ng i n t he f or m er san d bed r egi on and t he appl i cant's r el i ance on t he c oat i ng t o m i t i gat e addi t i onal cor r osi on t he s t af f i ni t i at ed f u rth e r re v ie w o f th e a p p li c a n t's in s p e c tio n p ro g ra m to e n s u re th a t th e c o a tin g w il l c o n tin u e to p e rf o rm its in te n d e d f u n c tio n f o r th e e x te n d e d p e rio d o f o p e ra tio n. Subsequen t t o t he audi t , i n r espo nse t o R AI 4.7.2-1, by l et t er dat ed J une 20, 2006, t he appl i cant pr ov i ded add i t i onal i nf or m at i on r egar di ng t he AM P and act i v i t i es a ss oci at ed wi t h dr y wel l she l l cor r osi on. T he s t af f's ev al uat i on of t he appl i cant's ad di t i onal i nf or m at i on and i t s c om m i t m ent s i s do cum ent ed i n SE R Sect i on 4.7.2. (4)
Suppr ess i on Cham ber (T or us). T he appl i cant cr edi t ed i t s Pr ot ect i v e C oat i ng Moni t or i ng and Mai nt enanc e Pr ogr am t o m oni t or/m ai nt ai n t he pr ot ect i v e co at i ngs i nsi de t he supp r ess i on c ham ber (t or us) t o m i t i gat e co r r osi on. T he s t af f's de t ai l ed ev al uat i on of t he a p p l i c a n t's Pr o t e c t i v e Co a t i n g Mo n i t o r i n g a n d Ma i n t e n a n c e Pr o g r a m i s a d d r e s s e d i n SER Sect i on 3.0.3.2.27.T h e s ta ff q u e s ti o n e d th e a p p l i c a b i l i ty a n d i m p l e m e n ta ti o n o f A S M E C o d e C a s e N-5 9 7-1 f or devel opi ng p i t dep t h acce pt ance cr i t er i a f or t he t or us. B ased on t he a ccept ance cr i t er i a dev el oped by t he appl i cant , an i sol at ed pi t of 0.125 i nche s di am et er on t he i nner s u rf a c e is c o n s id e re d a c c e p ta b le if its d e p th d o e s n o t e x c e e d 0.2 6 1 in c h e s. A c c o rd in g to th e a p p li c a n t, th e to ru s a s-b u il t w a ll th ic k n e s s is 0.3 8 5 in c h e s. T h e re f o re , a p it d e p th e q u a l to 6 7 p e rc e n t o f th e a s-b u i l t t h i c k n e s s i s c o n s i d e re d a c c e p ta b l e i f is o l a te d. F o r a cl ust er of pi t s wi t hi n a 2.5 i nche s di am et er ci r cl e t he ac cept abl e pi t dept h i s 0.141 i nche s or 37 per cent of t he as-bui l t t hi ck ness. T he ac cept abl e pi t dept h i ncl udes al l owanc e f or an ass um ed 0.0009 i nche s pe r y ear cor r osi on r at e ov er t he 4-y ear per i od bet ween i nspe ct i ons. R G 1.147 s t i pul at es t he f ol l owi ng c ondi t i on on t he us e of C ode C ase N-597-1: " (5) Fo r cor r osi on p hen om ena ot her t han f l ow-accel er at ed co r r osi on, use o f th e C o d e C a s e is s u b je c t to N R C re v ie w a n d a p p ro v a l. In s p e c tio n p la n s a n d w a ll th in n in g ra te s m a y b e d iff ic u lt to ju s tify fo r c e rta in d e g ra d a tio n m e c h a n is m s s u c h a s M IC a n d p itti n g."T he appl i cant st at ed t hat t he m ax i m um pi t dept h m easu r ed i n t he t or us i s 0.0685 i nche s (m easu r ed i n 1992 i n Bay 2). I t was e v al uat ed as acc ept abl e by t he des i gn c al cul at i ons at th a t tim e a n d w a s n o t b a s e d o n c a lc u la tio n C-1 3 0 2-1 8 7-E 3 1 0-0 3 8. T h is b o u n d in g w a ll t hi ckness i n t he t or us r em ai ns. T he cr i t er i on d evel ope d i n 20 02 f or l ocal t hi ckness a c c e p ta n c e p ro v i d e s a n e a s i e r m e th o d fo r e v a l u a ti n g a s-fo u n d p i ts. T h e re s u l ts w e re s h o w n to b e c o n s e rv a tiv e v e rs u s th e o rig in a l A S M E C o d e S e c tio n III a n d V III 3-130 r equi r em ent s f or t he t or us. T he t or us i nspe ct i on pr ogr am wi l l be enh ance d per I R 373695 t o i m pr ov e t he det ai l of t he ac cept ance cr i t er i a and m ar gi n m anagem ent r equi r em ent s by t he AS M E C ode Sect i on I I I cr i t er i a. T he appr oach use d i n C-1302-187-E310-038 wi l l be c la rif ie d a s to h o w it m a in ta in s th e c o d e re q u ire m e n ts. If A S M E C o d e C a s e N-5 9 7-1 is r equi r ed t o dev el op t hese cr i t er i a f or f ut ur e i nspe ct i ons, st af f r ev i ew and ap pr ov al wi l l be o b ta in e d. It s h o u ld a ls o b e n o te d th a t th e p ro g ra m h a s e s ta b li s h e d c o rro s io n ra te c rite ria and c ont i nues t o m oni t or per i odi cal l y t o v er i f y t hat t hey r em ai n bound ed.T he appl i cant's r espo nse cl ar i f i ed f or t he s t af f t hat pi t dept h ac cept ance cr i t er i a bas ed on A S M E C o d e C a s e N-5 9 7-1 h a d n o t b e e n im p le m e n te d a n d th a t if im p le m e n ta tio n s h o u ld b e c o n te m p la te d th e a p p li c a n t w il l s e e k s ta f f re v ie w a n d a p p ro v a l. T h e s ta f f f in d s th is cl ar i f i cat i on ac cept abl e t o r esol v e i t s c once r n about t he us e of AS M E C ode C ase N-597-1.F ro m th e a p p li c a n t's re s p o n s e , th e s ta f f d e te rm in e d th a t th e re w a s m in im a l m a rg in r em ai ni ng bet ween t he c ur r ent t hi ck ness and t he m i ni m um r equi r ed t hi ck ness f or t he t or us. D ur i ng a f ol l owup ons i t e audi t Apr i l 19-20, 2006, t he s t af f di sc uss ed wi t h t he appl i cant t he c ur r ent con di t i on of t he t or us, t he pi t dept h ac cept ance cr i t er i a, and t he scope of t he co at i ng i nspe ct i on co ndu ct ed e v er y 4 y ear s.T h e a p p li c a n t e x p la in e d th a t th e a v e ra g e re m a in in g th ic k n e s s o f th e to ru s is e s s e n tia ll y th e a s-b u il t th ic k n e s s (0.3 8 5 in c h e s). F iv e is o la te d p its , ra n g in g f ro m 0.0 4 2 to 0.068 i nche s i n dept h, ar e m oni t or ed and t r ended d ur i ng eac h i nspe ct i on. T he appl i cant supp l em ent ed i t s ea r l i er r espo nse t o doc um ent t hi s ex pl anat i on.T he appl i cant f ur t her ex pl ai ned t hat pi t dept h ac cept ance cr i t er i a bas ed on ASM E C ode C ase N-597-1 had n ev er been u sed t o f or acc ept abi l i t y of obs er v ed pi t t i ng. T he c ur r ent pr act i ce i s t o r ecor d and m oni t or al l pi t s ex ceed i ng 0.040 i nche s i n dept h. T he appl i cant s u p p le m e n te d its e a rlie r re s p o n s e to in d ic a te th a t, "P its g re a te r th a n 0.0 4 0 in c h e s in d e p th s h a ll b e d o c u m e n te d a n d s u b m itte d to e n g in e e rin g f o r e v a lu a tio n."I n i t s l et t er dat ed May 1, 2006, t he appl i cant sup pl em ent ed i t s ea r l i er r espo nse, com m i t t i ng (C om m i t m ent N o. 27) t o i nspe ct t he c oat i ng i n al l 20 bay s of t he s uppr ess i on c h a m b e r (to ru s) d u rin g th e p e rio d o f e x te n d e d o p e ra tio n. T h e f re q u e n c y o f in s p e c tio n w il l b e e v e ry o th e r re f u e li n g o u ta g e f o r th e c u rre n t c o a tin g s ys te m. If th e c o a tin g s ys te m is r epl aced , t he i nspe ct i on f r equenc y and s cope wi l l be r e-ev al uat ed. T he i nspe ct i on s cope w il l m e e t, a s a m in im u m , th e re q u ire m e n ts o f A S M E C o d e S u b s e c tio n IW E. T he a ppl i cant al so com m i t t ed (C om m i t m ent N o. 27) t o de v el op r ef i ned accep t ance cr i t er i a and t hr esho l ds f or ent er i ng c oat i ng def ect s an d unac cept abl e pi t dept hs i nt o t he cor r ect i v e ac t i on pr oces s f or f ur t her ev al uat i on. T hese i m pr ov em ent s wi l l be i ncor por at ed i nt o t he i nspe ct i on i m pl em ent i ng doc um ent s pr i or t o t he nex t i nspe ct i ons and pr i or t o t he per i od of ex t ended o per at i on.N R C i nspe ct or s c onduc t ed an i nspe ct i on dur i ng t he O y st er C r eek O ct ober 2006 r ef uel i ng out age. T he t eam doc um ent ed i t s f i ndi ngs i n i nspe ct i on r epor t 050002 19/200060 13, dat ed J anuar y 17, 2007, (M L07017 0396). T he i nspe ct i on t eam r ev i ewed s uppor t i ng docu m ent at i on and i nt er v i ewed app l i cant per sonn el t o co nf i r m t he adeq uacy of t he l i cens e r enewal con cl usi ons f r om t he v i sual i nspe ct i ons cond uct ed i n t he t or us. T he i nspe ct i on t eam not ed t hat com m i t m ent s f or t he t or us w er e m et. T he vi sual t est i nspe ct i on pr oced ur es c ont ai ned app r opr i at e cr i t er i a f or r epor t i ng nonc onf or m i ng 3-131 cond i t i ons and f or di spos i t i oni ng non-conf or m i ng c ondi t i ons. O n t he bas i s of t he i nspe ct i on r epor t f i ndi ngs, t he s t af f det er m i ned t hat com m i t m ent 2 f or t he t or us i dent i f i ed in th e a p p li c a n t's le tte r d a te d M a y 1 , 2 0 0 6 , h a s b e e n c o m p le te d. Based on t he s t af f's un der st andi ng of (1) t he c ur r ent con di t i on of t he t or us, (2) t he appl i cant's pl an t o r ef i ne t he pi t dept h ac cept ance cr i t er i a, and (3) t he s cope of t he c o a t i n g i n s p e c t i o n c o n d u c t e d e v e r y 4 y e a r s , t h e s t a f f c o n c l u d e s t h a t t h e a p p l i c a n t's AMP f or t he s uppr ess i on c ham ber (t or us) pr ov i des r easo nabl e as sur ance t hat t he ef f ect s of agi ng wi l l be ade quat el y m anaged dur i ng t he per i od of ex t ended o per at i on.T he s t af f r ev i ewed t hose por t i ons of t he AS M E S ect i on XI , Subsec t i on I W E P r ogr am f or whi ch t he appl i cant cl ai m ed c onsi st ency wi t h G ALL A M P XI.S1 wi t h t he ex cept i on desc r i bed bel ow. Based on i t s r ev i ew, t he s t af f i dent i f i ed f i v e open i t em s (O I s) 4.7.2-1.1, 4.7.2-1.2 , 4.7.2-1.3 , 4.7.2-1.4 , a n d 4.7.2-3 , p e rta i n i n g to a g i n g m a n a g e m e n t o f p ri m a ry c o n ta in m e n t (d ryw e ll s h e ll). T h e s ta f f re s o lu tio n o f th e s e o p e n ite m s is d is c u s s e d in Sect i on 4.7.2.Ex cept i on. I n t he LRA , t he appl i cant st at ed an e x cept i on t o t he G ALL R epor t r ecom m endat i ons i n t he "Pr ogr am D esc r i pt i on." Speci f i cal l y , t he ex cept i on s t at ed:N U R EG-1801 ev al uat i on i s ba sed on AS M E S ect i on XI , 2001 Edi t i on i ncl udi ng 2002 an d 2003 Addenda. T he c ur r ent O y st er C r eek AS M E S ect i on XI , Subsec t i on I W E pr ogr am pl an f or t he Fi r st T en-Y ear i nspe ct i on i nt er v al ef f ect i v e f r om S e p te m b e r 9 , 1 9 9 8 th ro u g h S e p te m b e r 9 , 2 0 0 8 , a p p ro v e d p e r 1 0 C F R 5 0.5 5 a , is b a s e d o n A S M E S e c t i o n X I , 1 9 9 2 E d i t i o n i n c l u d i n g 1 9 9 2 a d d e n d a. T h e n e xt 1 2 0-m o n th in s p e c tio n in te rv a l fo r O ys te r C re e k w il l i n c o rp o ra te th e re q u ire m e n ts spec i f i ed i n t he v er si on of t he AS M E C ode i ncor por at ed i nt o 10 CFR 50.55a 12 m o n th s b e f o re th e s ta rt o f th e in s p e c tio n in te rv a l.T he s t af f not ed t hat t he 1992 AS M E C ode Sect i on XI , Subsec t i on I W E, i ncl udi ng 1992 addend a, w a s in c o rp o ra te d in to 1 0 C F R 5 0.5 5 a a t th e tim e th e a p p li c a n t w a s re q u ire d to d e c la re its in s p e c tio n b a s is f o r th e c u rre n t 1 0-ye a r IW E in s p e c tio n in te rv a l. T h e a p p li c a n t w il l i n c o rp o ra te t he r equi r em ent s s peci f i ed i n t he AS M E C ode v er si on i ncor por at ed i nt o 10 CFR 50.55a 1 2 m o n th s b e f o re th e s ta rt o f th e n e x t 1 2 0-m o n th in s p e c tio n in te rv a l. A s th is in c o rp o ra tio n is cons i st ent wi t h t he r ecom m endat i ons i n t he G ALL R epor t , t he s t af f di d not con si der i t an ac t ual ex cept i on and f i nds i t acc ept abl e.I n i t s l et t er s da t ed Decem ber 3, 2006 a nd Decem ber 15, 2006, t he appl i cant r ev i sed t he com m i t m ent s f or t he I W E pr ogr am bas ed on t he r esul t s of t he O ct ober 2006 r ef uel i ng out age N D E in s p e c tio n a c tiv iti e s a s s o c ia te d w ith th e p rim a ry c o n ta in m e n t d ryw e ll s h e ll.S p e c ific a ll y, d u rin g th e 2 0 0 6 d ryw e ll li c e n s e re n e w a l i n s p e c tio n s , s ta n d in g w a te r w a s id e n tifie d in cont act wi t h t he dr y wel l she l l i nsi de t he t r ench i n bay #5 as des cr i bed bel ow. I nspe ct i on and ev al uat i on of t he dr y wel l she l l con cl udes t hat bec ause t he wat er env i r onm ent i s al kal i ne and o x y g e n i s l i m i te d d u ri n g p l a n t o p e ra ti o n , t h e e x p e c te d c o rro s i o n i s i n s i g n i fic a n t. H o w e v e r, A m e rG e n w il l fu rth e r e n h a n c e th is a g in g m a n a g e m e n t p ro g ra m to e n s u re p o te n tia l d ryw e ll cor r osi on i s de t ect ed and cor r ect i v e ac t i ons ar e t aken bef or e a l oss of t he dr y wel l i nt ended f unct i on. T he s peci f i c c om m i t m ent s whi ch t he appl i cant added ar e:14.
U T t hi ck ness m easu r em ent s wi l l be t aken f r om out si de t he dr y wel l i n t he s and bed r egi on dur i ng t he 2008 r ef uel i ng out age on t he l ocal l y t hi nned ar eas 3-132 e x a m i n e d d u ri n g th e O c to b e r 2 0 0 6 re fu e l i n g o u ta g e. T h e l o c a l l y th i n n e d a re a s a re d is tr ib u te d b o th v e r tic a lly a n d a r o u n d th e p e r im e te r o f th e d r yw e ll in a ll te n b a ys suc h t hat pot ent i al cor r osi on of t he dr y wel l she l l woul d be de t ect ed.15.
St ar t i ng i n 2010, dr y wel l she l l U T t hi ck ness m easu r em ent s wi l l be t aken f r om out si de t he dr y wel l i n t he s and bed r egi on i n t wo bay s pe r out age, suc h t hat in s p e c tio n s w ill b e p e r f o r m e d in a ll 1 0 b a ys w ith in a 1 0-ye a r p e r io d. T h e tw o b a ys w ith th e m o s t lo c a ll y th in n e d a re a s (b a y #1 a n d b a y #1 3) w il l b e in s p e c te d in 2010. I f t he UT ex am i nat i ons y i el d unac cept abl e r esul t s, t hen t he l ocal l y t hi nned a re a s in a ll 1 0 b a ys w il l b e in s p e c te d in th e re f u e li n g o u ta g e th a t th e u n a c c e p ta b le r esul t s ar e I dent i f i ed.16.
Per f or m v i sual i nspe ct i ons of t he dr y wel l she l l i nsi de t he t r ench es i n bay #5 and b a y #1 7 a n d t a k e U T m e a s u r e me n t s i n s i d e t h e s e t r e n c h e s i n 2 0 0 8 a t t h e s a me l ocat i ons ex am i ned i n 2006. R epeat (bot h t he UT and v i sual) i nspe ct i ons at re fu e l i n g o u ta g e s d u ri n g th e p e ri o d o f e x te n d e d o p e ra ti o n u n ti l th e tre n c h e s a re re s to re d to th e o rig in a l d e s ig n c o n f ig u ra tio n u s in g c o n c re te o r o th e r s u ita b le m at er i al t o pr event m oi st ur e col l ect i on i n t hese ar eas.17.
Per f or m v i sual i nspe ct i on of t he m oi st ur e bar r i er bet ween t he dr y wel l she l l and t he conc r et e f l oor cur b, i nst al l ed I nsi de t he dr y wel l dur i ng t he O ct ober 2006 r ef uel i ng out age, i n ac cor danc e wi t h AS M E S ect i on XI , Subsec t i on I W E dur i ng t he per i od of ex t ended o per at i on.A f te r e a c h in s p e c tio n , U T th ic k n e s s m e a s u re m e n ts re s u lts w il l b e e v a lu a te d a n d c o m p a re d w ith pr ev i ous U T t hi ck ness m easu r em ent s. I f uns at i sf act or y r esul t s ar e i dent i f i ed, t hen add i t i onal c o rre c tiv e a c tio n s w il l b e in iti a te d , a s n e c e s s a ry, to e n s u re th e d ryw e ll s h e ll in te g rity i s m ai nt ai ned t hr oughou t t he per i od of ex t ended o per at i on.D ur i ng t he Adv i sor y C om m i t t ee on React or Saf eguar ds (AC R S) m eet i ng on Febr uar y 1, 2007, t he appl i cant com m i t t ed t o per f or m an eng i neer i ng s t udy pr i or t o t he per i od of ex t ended o p e ra tio n in o rd e r to id e n tify o p tio n s to e li m in a te o r re d u c e th e le a k a g e in th e re f u e li n g c a v ity l i ner. T he appl i cant al so c om m i t t ed t o per f or m a 3-D (di m ensi onal) f i ni t e-el em ent anal y si s of t he dr y wel l she l l pr i or t o ent er i ng t he per i od of ex t ended o per at i on.I n i t s l et t er dat ed Febr uar y 15, 2007, t he appl i cant doc um ent ed t he c om m i t m ent s i t m ade t o t he AC R S and r ev i sed C om m i t m ent 27 ASM E S ect i on XI , Subsec t i on I W E. T he appl i cant al so a dded c o m m itm e n ts to in s p e c t th e d ryw e ll tre n c h e s a n d th e 1 0 d ryw e ll b a ys. T h e s p e c ific c o m m itm e n ts and i t em num ber s whi ch t he appl i cant added ar e:
1 8.
A m e rG e n w i l l p e rfo rm a 3-D fin i te e l e m e n t s tru c tu ra l a n a l y s i s o f th e p ri m a ry c o n ta in m e n t d ryw e ll s h e ll u s in g m o d e rn m e th o d s a n d c u rre n t d ryw e ll s h e ll t hi ck ness dat a t o bet t er quant i f y t he m ar gi n t hat ex i st s ab ov e t he Code r equi r ed m i ni m um f or buc kl i ng. T he anal y si s wi l l i ncl ude s ensi t i v i t y st udi es t o det er m i ne t he d e g re e to w h ic h u n c e rta in tie s in th e s ize o f th in n e d a re a s a f f e c t C o d e m a rg in s. If t he a nal y si s det er m i nes t hat t he d r y we l l shel l doe s not m eet r equ i r ed t hi ckness v al ues, t he N R C wi l l be n ot i f i ed i n acco r dan ce w i t h 10 C FR 50 r equ i r em ent s.1 9.
A m e r G e n w i l l p e r form a n e n g i n e e r i n g s t u d y t o i n ve s t i g a t e c o s t-e ff e c t i ve r epl acem ent or r epai r opt i ons t o el i m i nat e or r educ e r eact or cav i t y l i ner l eaka ge.
3-1332 0.
A m e rG e n is c o m m itte d to p e rf o rm v is u a l a n d U T in s p e c tio n s o f th e d ryw e ll s h e ll in t he i nspe ct i on t r ench es i n dr y wel l bay s #5 and #1 7 dur i ng t he O y st er C r eek 2008 r ef uel i ng out age (see i t em num ber 16 of Am er G en's I W E P r ogr am (C om m i t m ent 27), i n i t s l et t er 213 0-06-204 26). A m er G en w i l l ext end t hi s com m i t m ent and al so per f or m t hese i nspe ct i ons dur i ng t he 2010 r ef uel i ng out age. I n addi t i on, Am er G en wi l l m oni t or t he t wo t r ench es f or t he p r esen ce of wa t er dur i ng r ef uel i ng o ut age s.Vi sual and UT i nspe ct i ons of t he s hel l wi t hi n t he t r ench es wi l l con t i nue t o be per f or m ed unt i l no wat er i s i dent i f i ed i n t he t r ench es f or t wo con sec ut i v e r ef uel i ng out ages , at whi ch t i m e t he t r ench es wi l l be r est or ed t o t hei r or i gi nal des i gn conf i gur at i on (e.g., r ef i l l ed wi t h co ncr et e) t o m i ni m i z e t he r i sk of f ut ur e co r r osi on.21.
Per f or m t he f ul l sc ope of dr y wel l san d bed r egi on i nspe ct i ons pr i or t o t he per i od of e x te n d e d o p e ra tio n a n d th e n e v e ry o th e r re f u e li n g o u ta g e th e re a f te r. T h e f u ll s c o p e is d e f in e d a s:
- U T m easu r em ent s f r om i nsi de t he dr y wel l (i t em num ber 1)
- V is u a l in s p e c tio n s o f th e d r yw e ll e x te r n a l s h e ll e p o x y c o a tin g in a ll 1 0 b a ys (i t em num ber 4)
- I nspe ct i on of t he s eal at t he j unct i on bet ween t he s and bed r egi on conc r et e and t he em bedded dr y wel l she l l (i t em num ber 12)
- U T m easu r em ent s at t he ex t er nal l ocal l y t hi nned ar eas i nspe ct ed i n 2006 (i t em num ber s 9 a nd 14)Assoc i at ed wi t h t hese new c om m i t m ent s, t he s t af f i dent i f i ed l i cens i ng c ondi t i ons t hat r equi r e t he a p p l i c a n t t o i n c l u d e t h e UFS AR s u p p l e m e n t r e q u i r e d b y 1 0 CFR 5 4.2 1 (d) i n t h e n e x t UFS AR u p d a te , a s re q u ire d b y 1 0 C F R 5 0.7 1 (e), f o ll o w in g th e is s u a n c e o f th e re n e w e d li c e n s e; per f or m f ul l sc ope i nspe ct i ons of t he dr y wel l san d bed r egi on ev er y ot her r ef uel i ng out age; and m oni t or dr y wel l t r ench es e v er y r ef uel i ng out age t o i dent i f y and el i m i nat e t he s our ces of wat er and r ecei v e N R C appr ov al pr i or t o r est or i ng t he t r ench es t o t hei r or i gi nal des i gn c onf i gur at i on.T h e s ta f f f in d s th e a p p li c a n t's a d d iti o n a l c o m m itm e n ts f o r e n h a n c in g th e A S M E S e c tio n X I, S u b s e c tio n IW E a g in g m a n a g e m e n t p ro g ra m a c c e p ta b le; th e re f o re , th e c o n c e rn d e s c rib e d in R AI 4.7.2-5 i s r esol v ed.O p e ra tin g E x p e rie n c e. T h e a p p li c a n t s ta te d , in th e L R A , th a t A S M E S e c tio n X I, S u b s e c tio n IW E as d esc r i bed i n t he Fi r st 10-Y ear C ont ai nm ent (I W E) I nser v i ce I nspe ct i on Pr ogr am Pl an and Basi s i s ef f ect i v e Sept em ber 9, 1998, t o Sept em ber 9, 2008. Base l i ne i nspe ct i on of con t ai nm ent sur f aces was c om pl et ed i n 2000 and a s econ d i nspe ct i on was com pl et ed i n 2004. T he 2004 i nspe ct i on i dent i f i ed t wo r ecor dabl e co ndi t i ons, a l oose l ock nut on a s par e dr y wel l penet r at i on and a wel d r od s t uck t o t he unde r si de of t he dr y wel l head. Engi neer i ng ev al uat i on c oncl uded t hat t he st uck w el d r od h ad n o ad v er se i m pact on d r y we l l hea d st r uct ur al i nt egr i t y and t hat t he l oose l ock nut di d not af f ect t he s eal of t he c ont ai nm ent penet r at i on.T he appl i cant st at ed t hat t he uppe r r egi on of dr y wel l she l l has ex per i ence d l oss of m at er i al due to c o rro s io n f ro m w a te r le a k a g e in to th e g a p b e tw e e n th e c o n ta in m e n t a n d th e re a c to r b u il d in g in t he 1 980 s. A s a r esul t t he a r ea i s subj ect t o au gm ent ed e x am i nat i ons b y U T t hi ckness m e a s u re m e n ts a s re q u ire d b y A S M E C o d e S e c tio n X I, S u b s e c tio n IW E. U T m e a s u re m e n ts t aken i n 2004 showe d t hat t he dr y wel l she l l t hi ck ness m eet s ASM E C ode c r i t er i a and t hat t he r at e of cor r osi on i s de cl i ni ng. Engi neer i ng ev al uat i on of t he UT r esul t s al so c oncl uded t hat t he cont ai nm ent dr y wel l , con si der i ng t he c ur r ent cor r osi on r at e, i s c apabl e of per f or m i ng i t s i nt ended f u n c t i o n t h r o u g h t h e p e r i o d o f e x t e n d e d o p e r a t i o n. F u r t h e r d i s c u s s i o n i s p r o v i d e d i n L RA Sect i on 4.7.2.
3-134 T he appl i cant st at ed t hat t he s and bed r egi on al so e x per i ence d l oss of m at er i al due t o co r r osi on at t r i but ed t o t he pr esen ce o f ox y genat ed wet san d and e x acer bat ed by t he pr esen ce o f chl or i de and s ul f at e i n t he s and bed r egi on. As a co r r ect i v e m easu r e, t he s and was r em ov ed and a pr ot ect i v e co at i ng was appl i ed t o t he s hel l t o m i t i gat e f ur t her cor r osi on. Subsequen t i nspe ct i ons c o n f irm e d th a t c o rro s io n o f th e s h e ll h a d b e e n a rre s te d. T h e c o a tin g is m o n ito re d p e rio d ic a ll y u n d e r th e P ro te c tiv e C o a tin g M o n ito rin g a n d M a in te n a n c e P ro g ra m. T h e s ta f f e v a lu a tio n o f th is pr ogr am i s ad dr ess ed i n SE R Sect i on 3.0.3.2.27.T h e a p p li c a n t s ta te d th a t th e s u p p re s s io n c h a m b e r (to ru s) a n d v e n t s ys te m w e re o rig in a ll y coat ed wi t h C ar bol i ne Car bo-Zi nc 1 1 pai nt. T he c oat i ng i s i nspe ct ed ev er y out age and r epai r ed, as r equi r ed, t o pr ot ect t he t or us s hel l and t he v ent sy st em f r om cor r osi on.T h e a p p li c a n t s ta te d th a t fr o m o p e ra tin g e x p e rie n c e it h a d c o n c lu d e d th a t A S M E S e c tio n X I, S ubse ct i on I W E i s ef f ect i v e f or m ana gi ng a gi ng e f f ect s of pr i m ar y cont ai nm ent sur f aces.I n PB D-AM P-B.1.27, t he appl i cant ex panded i t s di sc uss i on of oper at i ng ex per i ence t o i ncl ude i ndus t r y oper at i ng ex per i ence and ad di t i onal det ai l s of t he pl ant-spec i f i c c ont ai nm ent degr adat i on. T he appl i cant st at ed t hat i ndus t r y oper at i ng ex per i ence had c onf i r m ed t hat cor r osi on had occ ur r ed i n co nt ai nm ent she l l s. I N s 86-99, 88-82, and 89-79 des cr i bed occ ur r ence s of cor r osi on i n st eel con t ai nm ent she l l s. G L 87-05 addr ess ed t he pot ent i al f or cor r osi on of BW R Mar k I st eel dr y wel l s i n t he " sand poc ket r egi on." Mor e r ecen t l y , I N 97-10 i dent i f i ed s peci f i c l ocat i ons wher e co ncr et e co nt ai nm ent s ar e su sc ept i bl e t o l i ner pl at e co r r osi on.Pl ant oper at i ng ex per i ence sho ws t hat cor r osi on has occ ur r ed i n se v er al con t ai nm ent l ocat i ons i ncl udi ng t he dr y wel l she l l i n t he s and bed r egi on, t he dr y wel l she l l abov e t he s and bed r egi on, a n d th e s u p p re s s io n c h a m b e r a n d v e n t s ys te m. In a ll c a s e s th e A S M E S e c tio n X I, Subsect i on I W E P r ogr am has i dent i f i ed and cor r ect ed t he degr adat i on. Ex per i ence wi t h t he A S M E S e c tio n X I, S u b s e c tio n IW E P ro g ra m s h o w s th a t it i s e f f e c tiv e in m a n a g in g a g in g e f f e c ts f or t he p r i m ar y cont ai nm ent and i t s com pon ent s.T he appl i cant i ncl uded t he f ol l owi ng di sc uss i on and t hr ee ex am pl es o f oper at i ng ex per i ence as ev i denc e t hat t he AS M E S ect i on XI , Subsec t i on I W E P r ogr am ef f ect i v el y ass ur es t hat i nt ended f unct i ons wi l l be m ai nt ai ned c onsi st ent wi t h t he CLB f or t he per i od of ex t ended o per at i on:T h e O ys te r C re e k A S M E S e c tio n X I, S u b s e c tio n IW E P ro g ra m a s d e s c rib e d in O y st er C r eek 10 Y ear C ont ai nm ent (I W E) I nser v i ce I nspe ct i on Pr ogr am Pl an and Basi s i s i n ef f ect f r om Sept em ber 9, 1998 t o Sept em ber 9, 2008. Base l i ne i nspe ct i on of t he dr y wel l was c om pl et ed dur i ng 2000 , r ef uel i ng out age. T he supp r ess i on c ham ber (t or us) v apor r egi on bas e l i ne i nspe ct i on was com pl et ed d u rin g 2 0 0 0 , re f u e li n g o u ta g e. Al t hough t he O y st er C r eek AS M E S ect i on XI , Subsec t i on I W E P r ogr am im p le m e n ta tio n is re c e n t, th e p o te n tia l fo r lo s s o f m a te ria l, d u e to c o rro s io n , in i nacc ess i bl e ar eas of t he c ont ai nm ent dr y wel l she l l was f i r st r ecog ni z ed i n 1980 when wat er was d i sc ov er ed c om i ng f r om t he s and bed r egi on dr ai ns. C or r osi on was l at er con f i r m ed by ul t r ason i c t hi ck ness (U T) m easu r em ent s t aken dur i ng t he 1 9 8 6 re f u e li n g o u ta g e. A s a re s u lt, s e v e ra l c o rre c tiv e a c tio n s w e re in iti a te d to d e te rm in e th e e x te n t o f c o rro s io n , e v a lu a te th e in te g rity o f th e d ryw e ll , m iti g a te acc el er at ed c or r osi on, and m oni t or t he c ondi t i on of con t ai nm ent sur f aces. T he c o rre c tiv e a c tio n s in c lu d e e x te n s iv e U T m e a s u re m e n ts o f th e d ryw e ll s h e ll t hi ck ness , r em ov al of t he s and i n t he s and bed r egi on, cl eani ng and coat i ng ex t er i or sur f aces i n ar eas wher e sa nd was r em ov ed, and an engi neer i ng 3-135 ev al uat i on t o co nf i r m t he dr y wel l st r uct ur al i nt egr i t y. A cor r osi on m oni t or i ng pr ogr am was e st abl i shed , i n 1987, f or t he dr y wel l she l l abov e t he s and bed r egi on t o ens ur e t hat t he c ont ai nm ent v ess el i s c apabl e of per f or m i ng i t s i nt ended f u n c t i o n s. El e m e n t s o f t h e p r o g r a m h a v e b e e n i n c o r p o r a t e d i n t o t h e ASM E Sect i on XI , Subsec t i on I W E and pr ov i de f or (1) per i odi c UT i nspe ct i ons of t he s h e l l t h i c k n e s s a t c r i t i c a l l o c a t i o n s , (2) c a l c u l a t i o n s w h i c h e s t a b l i s h c o n s e r va t i ve c o r r o s i o n r a t e s , (3) p r o j e c t i o n s o f t h e s h e l l t h i c k n e s s b a s e d o n t h e c o n s e r va t i ve cor r osi on r at es, and (4) dem onst r at i on t hat t he m i ni m um r equ i r ed sh el l t hi ckness i s i n ac cor danc e wi t h AS M E C ode.Addi t i onal l y , t he NR C was n ot i f i ed of t hi s po t ent i al gener i c i ss ue t hat l at er bec am e th e s u b je c t o f N R C In f o rm a tio n N o tic e 8 6-9 9 a n d G e n e ric L e tte r 8 7-0 5. A sum m ar y of t he oper at i ng ex per i ence , m oni t or i ng ac t i v i t i es, and c or r ect i v e ac t i ons ta k e n to e n s u re th a t th e p rim a ry c o n ta in m e n t w il l p e rf o rm its in te n d e d f u n c tio n s is d is c u s s e d b e lo w. 1.
D r y wel l Shel l i n t he Sand Bed R egi on:
T he dr y wel l she l l i s f abr i cat ed f r om AS T M A-212-61T G r. B st eel pl at e.T he s hel l was c oat ed on t he i nsi de s ur f ace wi t h an i nor gani c z i nc (C ar bol i ne c ar boz i nc 1 1) and on t he out si de s ur f ace wi t h " R ed Lead" pr i m er i dent i f i ed as T T-P-86C T y pe I. T he r ed l ead c oat i ng c ov er ed t he e n tire e x te rio r o f th e v e s s e l fro m e le v a tio n 8' 1 1.2 5" (F il l s la b le v e l) to e le v a tio n 9 4' (b e lo w d ryw e ll f la n g e). T h e s a n d b e d re g io n w a s f il le d w ith dr y san d as spe ci f i ed by AS T M 633. Leak age of wat er f r om t he s and bed dr ai ns was obs er v ed dur i ng t he 1980 and 19 83 r ef uel i ng out ages. A ser i es o f in v e s tig a tio n s w e re p e rf o rm e d to id e n tify th e s o u rc e o f th e w a te r a n d its l eak pat h. T he r esul t s c oncl uded t hat t he s our ce o f wat er was f r om t he r eact or cav i t y , whi ch i s f l ooded d ur i ng r ef uel i ng out ages. As a r esul t of t he pr esen ce of wa t er i n t he sa nd b ed r egi on, ext ensi v e U T t hi ckness m e a s u re m e n ts (a b o u t 1 0 0 0) o f th e d ryw e ll s h e ll w e re ta k e n to d e te rm in e if de gr ad at i on wa s oc c ur r i ng. Thes e meas ur ement s c or r es po nd ed t o k no wn w a te r le a k s a n d in d ic a te d th a t w a ll th in n in g h a d o c c u rre d in th is re g io n.
B ecau se of r edu ced t hi ckness r ead i ngs, add i t i ona l t hi ckness m easu r em ent s wer e obt ai ned t o det er m i ne t he v er t i cal pr of i l e of t he th i n n i n g. A tre n c h w a s e x c a v a te d i n s i d e th e d ry w e l l , i n th e c o n c re te flo o r, i n t he ar ea wher e t hi nni ng at t he f l oor l ev el was m ost sev er e.M easu r em ent s t aken f r om t he ex cav at ed t r ench i ndi cat ed t hat t hi nni ng of t he em bedded she l l i n co ncr et e wer e no m or e se v er e t han t hose t aken at t he f l oor l ev el and be cam e l ess sev er e at t he l ower por t i ons of t he s and bed r egi on. C onv er sel y , m easu r em ent s t aken i n ar eas wher e t hi nni ng was not i dent i f i ed at t he f l oor l ev el sho wed no i ndi cat i on of si gni f i cant t hi nni ng i n t he em bedded she l l. Asi de f r om U T t hi ck ness m easu r em ent s pe r f or m ed b y p l a n t s t a f f , i n d e p e n d e n t a n a l y s i s w a s p e r f o r me d b y t h e E P RI ND E C ent er and t he G E U l t r a I m age I I I " C" sc an t opogr aphi cal m appi ng s y st em.T he i ndepen dent t est s c onf i r m ed t he UT r esul t s. T he G E U l t r a I m age r esul t s wer e us ed as bas el i ne pr of i l e t o t r ack con t i nued c or r osi on.
3-136 T o v al i dat e U T m easu r em ent s an d ch ar act er i z e t he f or m of dam age and i t s c ause (i.e., due t o t he pr esen ce o f con t am i nant s, m i cr obi ol ogi cal spec i es, or bot h) cor e sa m pl es o f t he dr y wel l she l l wer e obt ai ned at sev en l ocat i ons. T he c or e sa m pl es v al i dat ed t he UT m easu r em ent s an d conf i r m ed t hat t he c or r osi on of t he dr y wel l i s du e t o t he pr esen ce o f ox y genat ed wet san d and e x acer bat ed by t he pr esen ce o f chl or i de and sul f at e i n t he sa nd b ed r egi on. A cont am i nat e con cent r at i ng m echa ni sm due t o al t er nat e wet t i ng and dr y i ng of t he s and m ay hav e al so c ont r i but ed t o t he c or r osi on phen om enon. I t was t her ef or e co ncl uded t hat t he opt i m um m et hod f or m i t i gat i ng t he c or r osi on i s by (1) r em ov al of t he s and t o br eak u p th e g a lv a n ic c e ll , (2) re m o v a l o f th e c o rro s io n p ro d u c t fr o m th e s h e ll a n d (3) a p p li c a tio n o f a p ro te c tiv e c o a tin g.
R em ov al of san d was i ni t i at ed dur i ng 1988 by r em ov i ng s heet m et al f r om ar ound t he v ent header s t o pr ov i de ac ces s t o t he s and bed f r om t he T or us r oom. D ur i ng o per at i ng cy cl e 13 som e san d w as r em oved and access h o l e s w e re c u t i n to th e s a n d b e d re g i o n th ro u g h th e s h i e l d w a l l. T h e w o rk wa s f i ni shed i n D ecem ber 199 2. A f t er sand r em oval , t he co ncr et e sur f ace bel ow t he s and was f ound t o be un f i ni shed wi t h i m pr oper pr ov i si ons f or wat er dr ai nage. C or r ect i v e ac t i ons t aken i n t hi s r egi on dur i ng 1992 i ncl uded; (1) cl eani ng of l oose r ust f r om t he dr y wel l she l l , f ol l owed by appl i cat i on of epox y coa t i ng and (2) r em ov i ng t he l oose debr i s f r om t he c o n c re te f lo o r f o ll o w e d b y re b u il d in g a n d re s h a p in g th e f lo o r w ith e p o x y to a l l o w d r a i n a g e o f a n y w a t e r t h a t ma y l e a k i n t o t h e r e g i o n. UT m easu r em ent s t aken f r om t he out si de af t er cl eani ng v er i f i ed l oss of m at er i al pr oj ect i ons t hat had be en m ade bas ed on m easu r em ent s t aken f r om t he i nsi de of t he dr y wel l. T her e wer e, howev er , som e ar eas t hi nner t han pr oj ect ed; but i n al l cas es e ngi neer i ng anal y si s de t er m i ned t hat t he dr y we l l shel l t hi ckness sa t i sf i ed A S M E C ode r equ i r em ent s.
T he pr ot ect i v e co at i ng m oni t or i ng and m ai nt enanc e pr ogr am was r ev i sed to in c lu d e m o n ito rin g o f th e c o a tin g s o f e x te rio r s u rf a c e s o f th e d ryw e ll in t he s and bed r egi on. T he c oat ed s ur f aces of t he f or m er san d bed r egi on wer e su bseq uent l y i nspe ct ed dur i ng r ef uel i ng out ages of 1994, 1996, 2000, and 20 04. T he i nspe ct i ons showe d no c oat i ng f ai l ur e or si gns of det er i or at i on. T he i nspe ct i ons pr ov i de obj ect i v e ev i denc e t hat t he coat i ng i s i n a goo d co ndi t i on and wi l l pr ov i de adeq uat e pr ot ect i on t o t he d ryw e ll s h e ll in th e s a n d b e d re g io n. E v a lu a tio n o f U T m e a s u re m e n ts ta k e n f ro m in s id e th e d ryw e ll , in th e in th e f o rm e r s a n d b e d re g io n , in 1 9 9 2 , 1 9 9 4 , a n d 1 9 9 6 c o n firm e d th a t c o rro s i o n i s m i ti g a te d. I t i s th e re fo re conc l uded t hat cor r osi on i n t he s and bed r egi on has been a r r est ed and no f u rth e r lo s s o f m a te ria l i s e x p e c te d. M o n ito rin g o f th e c o a tin g in accor dan ce w i t h t he p r ot ect i v e coa t i ng m oni t or i ng a nd m ai nt ena nce p ro g ra m , w il l c o n tin u e to e n s u re th a t th e c o n ta in m e n t d ryw e ll s h e ll m a in ta in s its in te n d e d f u n c tio n d u rin g th e p e rio d o f e x te n d e d o p e ra tio n. 2.
D r y wel l Shel l abov e Sand Bed R egi on:
T he UT i nv est i gat i on phas e (1986 t hr ough 19 91) al so i dent i f i ed l oss of m at er i al , due t o cor r osi on, i n t he u ppe r r egi ons o f t he d r y we l l shel l. T hese 3-137 r egi ons wer e handl ed s epar at el y f r om t he s and bed r egi on bec ause of t he si gni f i cant di f f er ence i n co r r osi on r at e and p hy si cal di f f er ence i n des i gn.C or r ect i v e ac t i on f or t hese r egi ons i nv ol v ed pr ov i di ng a c or r osi on a ll o w a n c e b y d e m o n s tra tin g , th ro u g h a n a ly s is , th a t th e o rig in a l d ryw e ll desi gn pr ess ur e was cons er v at i v e. Am endm ent 165 t o t he O y st er C r eek T e c h n ic a l S p e c ific a tio n s re d u c e d th e d ryw e ll d e s ig n p re s s u re f ro m 6 2 p s ig t o 44 ps i g. T he new de si gn pr ess ur e co upl ed wi t h m easu r es t o pr ev ent w a te r in tru s io n in to th e g a p b e tw e e n th e d ryw e ll s h e ll a n d th e c o n c re te w il l a ll o w th e u p p e r p o rtio n o f th e d ryw e ll to m e e t A S M E C o d e re q u ire m e n ts.
Or i g i n a l l y , t h e k n o w l e d g e o f t h e e x t e n t o f c o r r o s i o n w a s b a s e d o n UT m easu r em ent s go i ng c om pl et el y ar ound t he i nsi de of t he dr y wel l at s e v e ra l e le v a tio n s. A t e a c h e le v a tio n , a b e lt-li n e s w e e p w a s u s e d w ith r eadi ngs t aken on as l i t t l e as 1" cen t er s wher ev er t hi ck ness cha nged bet ween s ucc ess i v e nom i nal 6" cen t er s. Si x-by-si x gr i ds t hat ex hi bi t ed t he w o rs t m e ta l l o s s a ro u n d e a c h e le v a tio n w e re e s ta b li s h e d u s in g th is appr oach and i ncl uded i n t he Dr y wel l C or r osi on I nspe ct i on Pr ogr am.
As ex per i ence i ncr ease d wi t h eac h dat a co l l ect i on c am pai gn, onl y gr i ds s h o w i n g e v i d e n c e o f a c h a n g e w e r e r e t a i n e d i n t h e i n s p e c t i o n p r o g r a m.Addi t i onal ass ur ance r egar di ng t he adeq uacy of t hi s i nspe ct i on pl an was obt ai ned by a co m pl et el y r andom i z ed i nspe ct i on, i nv ol v i ng 49 g r i ds t hat show ed t hat al l i nspe ct i on l ocat i ons sa t i sf i ed A S M E C ode r equ i r em ent s.Ev al uat i on of U T m easu r em ent s t aken t hr ough 20 00 c oncl uded t hat c o rro s io n is n o lo n g e r o c c u rrin g a t tw o (2) e le v a tio n s , th e 3 rd e le v a tio n is u n d e rg o in g a c o rro s io n ra te o f 0.6 m il s/ye a r, w h il e th e 4 th e le v a tio n s is subj ect t o 1.2 m i l s/y ear. T he r ecen t U T m easu r em ent s (2004) con f i r m ed t hat t he c or r osi on r at e co nt i nues t o dec l i ne. T he t wo el ev at i ons t hat pr ev i ousl y ex hi bi t ed no i ncr ease i n co r r osi on c ont i nue t he no c or r osi on i ncr ease t r end. T he r at e of cor r osi on f or t he 3r d el ev at i on dec r ease d f r om 0.6 m i l s/y ear t o 0.4 m i l s/y ear. T he r at e of cor r osi on f or t he 4t h el ev at i on decr ease d f r om 1.2 m i l s/y ear t o 0.75 m i l s/y ear. Af t er eac h U T ex am i nat i on cam pai gn, an eng i neer i ng anal y si s i s pe r f or m ed t o ens ur e t he r equi r ed m i ni m um t hi ck ness i s pr ov i ded t hr ough t he per i od of ex t ended o per at i on.T hus cor r osi on of t he dr y wel l she l l i s c onsi der ed a TLA A f ur t her des cr i bed in S e c tio n 4.7.2. 3.
Suppr ess i on Cham ber (T or us) and Vent Sy st em T h e O y s te r C re e k s u p p re s s i o n c h a m b e r (t o ru s) a n d v e n t s y s te m w e re o rig in a ll y c o a te d w ith C a rb o li n e C a rb o-Z in c 1 1 p a in t. T h e c o a tin g is i nspe ct ed per i odi cal l y and r epai r ed t o pr ot ect t he T or us s hel l and t he v ent s ys te m in a c c o rd a n c e w ith s p e c ific a tio n S P-1 3 0 2-5 2-1 2 0. A s a re s u lt w a ll th in n in g o f th e to ru s s h e ll a n d th e v e n t s ys te m h a s n o t b e e n a n is s u e. A r ev i ew of pas t i nspe ct i ons of t he t or us s hel l and t he v ent sy st em i ndi cat es t he m aj or i t y of t he pr obl em s f ound ha v e been at t r i but ed t o bl i st er i ng of coat i ng i n sm al l ar eas, l ocal i z ed pi t t i ng. I n 1983, pi t t ed s ur f aces of t he i m m er sed t or us s hel l wer e r epai r by wel di ng. T he t or us s hel l , t he i nt er i or of 3-138 d o w n c o m e rs , a n d th e e n ti re i n te ri o r s u rfa c e s o f th e v e n t s y s te m w e re r e c o a te d w ith M o b il 7 8-H i B u ild E p o x y.
In s p e c tio n p e rf o rm e d in 2 0 0 2 f o u n d th e c o a tin g to b e in g o o d c o n d iti o n in th e v a p o r a re a o f th e to ru s a n d v e n t h e a d e r, a n d in f a ir c o n d iti o n in i m m er si on. C oat i ng def i ci enci es i n i m m er si on i ncl ude bl i st er i ng, r andom and m echa ni cal dam age. Bl i st er i ng oc cur s pr i m ar i l y i n t he s hel l i nv er t but was al so n ot ed on t he uppe r she l l near t he wat er l i ne. T he f r act ur ed b li s te rs w e re re p a ire d to re e s ta b li s h th e p ro te c tiv e c o a tin g b a rrie r. T h is is a n o t h e r e x a m p l e o f o b j e c t i v e e v i d e n c e t h a t t h e Oy s t e r Cr e e k ASM E Sect i on XI , Subsec t i on I W E P r ogr am can i dent i f y degr adat i on and im p le m e n t c o r r e c tiv e a c tio n s to p r e v e n t th e lo s s o f th e c o n ta in m e n t's i nt ended f unct i on.
W h il e b li s te rin g is c o n s id e re d a d e f ic ie n c y, i t is s ig n ific a n t o n ly w h e n it i s f r act ur ed and ex pose s t he bas e m et al t o co r r osi on at t ack. T he m aj or i t y of th e b li s te rs re m a in in ta c t a n d c o n tin u e s to p ro te c t th e b a s e m e ta l;cons equent l y t he c or r osi on r at es a r e l ow. Q ual i t at i v e as ses sm ent of t he i d e n ti fie d p i ts i n d i c a te th a t t h e m e a s u re d p i t d e p th s (5 0 m i l s m a x) a re si gni f i cant l y l ess t han t he c r i t er i a es t abl i shed i n Speci f i cat i on SP-1302-52-120 (141- 261 m i l s, depend i ng on d i am et er of t he pi t and s p a c i n g b e tw e e n p i ts).I n PBD-AMP-B.1.2 7 , t h e a p p l i c a n t c o n c l u d e d t h a t t h e o p e r a t i n g e x p e r i e n c e o f t h e ASM E S e c t i o n X I , S u b s e c t i o n I W E P r o g r a m s h o w s n o a d v e r s e t r e n d i n p e r f o r ma n c e. P r o b l e ms id e n tifie d w il l n o t c a u s e s ig n ific a n t im p a c t to th e s a f e o p e ra tio n o f th e p la n t, a n d a d e q u a te c o r r e c t i v e a c t i o n s w e r e t a k e n t o p r e v e n t r e c u r r e n c e. Th e i m p l e m e n t a t i o n o f t h e ASM E Sect i on XI , Subsec t i on I W E P r ogr am wi l l ef f ect i v el y i dent i f y con t ai nm ent agi ng ef f ect s pr i or t o t he lo s s o f th e c o n ta in m e n t fu n c tio n. A p p ro p ria te g u id a n c e f o r e v a lu a tio n , re p a ir, o r re p la c e m e n t is pr ov i ded f or l ocat i ons sus cept i bl e t o degr adat i on. Per i odi c s el f-ass ess m ent s of t he pr ogr am i d e n t i f y a r e a s t h a t n e e d i mp r o v e me n t t o ma i n t a i n p e r f o r ma n c e o f t h e p r o g r a m.I n i t s l et t er dat ed Decem ber 3, 2006, t he appl i cant r ev i sed t he oper at i ng ex per i ence sec t i on of t he AM P B.1.2.7 t o i ncl ude ex per i ence f r om t he O ct ober 2006 r ef uel i ng out age. T he addi t i onal o p e ra tin g e x p e rie n c e in c lu d e d th e f o ll o w in g: D ur i ng t he O ct ober 2006 r ef uel i ng out age UT t hi ck ness m easu r em ent s i n t he s a n d b e d re g io n w e re m a d e in s id e th e d ryw e ll a t th e s a m e lo c a tio n s e x a m in e d in 1 9 9 6. T h e re s u lts o f th e s ta tis tic a l a n a ly s is o f th e 2 0 0 6 U T d a ta w e re c o m p a re d to th e 1 9 9 2 , 1 9 9 4 a n d 1 9 9 6 d a ta s ta tis tic a l a n a ly s is re s u lts. S o m e o f th e 1 9 9 6 d a ta cont ai ned ano m al i es t hat ar e not r eadi l y j ust i f i abl e but t he anom al i es d i d not si gni f i cant l y cha nge t he r esul t s. T he c om par i son conf i r m ed t hat cor r osi on on t he ex t er i or sur f aces of t he dr y wel l she l l i n t he s and bed r egi on has been a r r est ed.I n ad di t i on 1 06 U T t hi ckness m easu r em ent s we r e m ade i n l ocal l y t hi nne d ar eas, i d e n t i f i e d i n 1 9 9 2 , f r o m o u t s i d e t h e d r y w e l l i n t h e s a n d b e d r e g i o n. Th e 2 0 0 6 UT t hi ck ness r eadi ngs i n t he l ocal l y t hi nned ar eas ar e l ower when c om par ed t o 1992 r eadi ngs. T hi s i s l ar gel y due t o us i ng a m or e ac cur at e U T i nst r um ent and t he pr oced ur e us ed t o t ake t he m easu r em ent s, whi ch i nv ol v ed m ov i ng t he i nst r um ent 3-139 wi t hi n t he l ocal l y t hi nned ar ea i n or der t o l ocat e t he m i ni m um t hi ck ness i n t hat ar ea. I n addi t i on t he i nner dr y wel l she l l sur f ace coul d be s ubj ect t o so m e i nsi gni f i cant cor r osi on due t o wat er i nt r usi on ont o t he em bedded she l l (see di sc uss i on bel ow). Addi t i onal m easu r em ent s of t he l ocal l y t hi nned ar eas wi l l be t aken i n 2008 usi ng t he s am e t y pe of U T i nst r um ent t o bet t er cor r el at e t he m e a s u re m e n ts a n d c o n f irm s ig n ific a n t c o rro s io n is n o t o n g o in g in th e in n e r d ryw e ll shel l sur f ace.D ur i ng t he 2006 r ef uel i ng out age (1R 21), U T t hi ck ness m easu r em ent s wer e t aken a t t h e 4 e l e v a t i o n s d i s c u s s e d a b o v e i n a c c o r d a n c e w i t h t h e Oy s t e r Cr e e k ASM E S e c t i o n X I , S u b s e c t i o n I W E a g i n g ma n a g e me n t p r o g r a m. Th e r e s u l t s o f t h e UT t hi ck ness m easu r em ent s i ndi cat ed t hat no obs er v abl e co r r osi on i s oc cur r i ng at el ev at i ons 51' 10" and 60' 10". A si ngl e l ocat i on (Bay 15 -23L) of t he 3r d el ev at i on (50 '2") con t i nues t o ex per i ence m i nor cor r osi on at a r at e of 0.66 m i l s/y r. T he c o rro s io n ra te f o r th e 4 th e le v a tio n (8 7' 5") is n o w s ta tis tic a ll y i n s ig n ific a n t a n d th is el ev at i on c an be c onsi der ed as no l onger under goi ng obs er v abl e co r r osi on.I n addi t i on UT m easu r em ent s wer e t aken on 2 l ocat i ons (bay #15 an d bay #17) at el ev at i on 23' 6" wher e t he c i r cum f er ent i al wel d j oi ns t he bot t om sph er i cal pl at es and t he m i ddl e sp her i cal pl at es. T hi s wel d j oi ns p l at es t hat ar e 1.154" t hi ck t o t he p l a te s th a t a re 0.7 7 0" th i c k. T h e s e tw o b a y s w e re s e l e c te d b e c a u s e th e y a re am ong t hose t hat hav e hi st or i cal l y ex per i ence d t he m ost cor r osi on i n t he s and bed r egi on. At eac h l ocat i on 49 UT s wer e t aken abov e t he wel d on t he 0.770" t hi ck pl at e and 4 9 U T s wer e t aken bel ow t he wel d on t he 1.154" t hi ck pl at e. T he m i ni m um av er age t hi ck ness m easu r ed on t he 0.770" t hi ck pl at e i s 0.766" and 1.160" on t he 1.154" t hi ck pl at e. T he m i ni m um m easu r ed l ocal t hi ck ness on t he 0.770" t hi ck pl at e i s 0.628" and on t he 1.154" t hi ck pl at e i s 0.867". T he m i ni m um m easu r ed gene r al and l ocal t hi ck ness on eac h pl at e m eet s t he m i ni m um t hi ck ness r equi r ed t o sa t i sf y AS M E st r ess r equi r em ent s wi t h an ad equat e m ar gi n.U T m easu r em ent s wer e al so t aken on 2 l ocat i ons (bay #15 an d bay #19) at el ev at i on 71' 6" wher e t he c i r cum f er ent i al wel d j oi ns t he t r ansi t i on pl at es (r ef er r ed t o as t he k nuck l e pl at es) bet ween t he c y l i nder and t he s pher e. T hi s wel d j oi ns t he knuc kl e pl at es, whi ch a r e 2.625" t hi ck t o t he c y l i nder pl at es, whi ch a r e 0.640" th ic k. T h e s e tw o b a ys w e re s e le c te d b e c a u s e th e y a ls o h a v e h is to ric a ll y e x p e r i e n c e d t h e mo s t c o r r o s i o n i n t h e s a n d b e d r e g i o n. A t e a c h l o c a t i o n 4 9 UTs wer e t aken abov e t he wel d on t he 0.640" t hi ck pl at e and 4 9 U T s wer e t aken bel ow t he wel d on t he 2.625" t hi ck pl at e. T he m i ni m um m easu r ed av er age t hi ck ness on t he 0.640" t hi ck pl at e i s 0.624" and 2.530" on t he 2.625" t hi ck pl at e. T he m i ni m um m easu r ed l ocal t hi ck ness on t he 0.640" t hi ck pl at e i s 0.449" and 2.428" on t he 2.625" t hi ck pl at e. T he m i ni m um m easu r ed g ene r al and l ocal t hi ckness o n ea ch p la te m e e ts th e m in im u m th ic k n e s s re q u ire d to s a tis f y A S M E s tre s s re q u ire m e n ts wi t h an ad equat e m ar gi n.I nner D r y wel l Shel l i n t he Em bedded R egi onIn 1 9 8 6 , a s p a rt o f a n o n g o in g e f f o rt a t th e O ys te r C re e k G e n e ra tin g S ta tio n to i nv est i gat e t he i m pact of wat er on t he out er dr y wel l she l l , con cr et e was ex cav at ed a t tw o lo c a tio n s in s id e th e d ryw e ll (re f e rre d to a s tre n c h e s) to e x p o s e th e d ryw e ll 3-140 s h e l l b e l o w t h e E l e v a t i o n 1 0'-3" c o n c r e t e f l o o r l e v e l t o a l l o w u l t r a s o n i c (UT)m easu r em ent s t o be t aken t o ch ar act er i z e t he v er t i cal pr of i l e of cor r osi on i n t he s a n d b e d re g i o n o u ts i d e th e s h e l l. T h e tre n c h e s (a p p ro x i m a te l y 1 8" w i d e) w e re lo c a te d in b a ys #5 a n d #1 7 w ith th e b o tto m o f th e tre n c h e s a t a p p ro x im a te el ev at i ons 8'-9" and 9-3" r espe ct i v el y (T he el ev at i on of t he s and bed r egi on f l oor o u ts i d e th e d ry w e l l i s a p p ro x i m a te l y 8'-1 1").Fol l owi ng UT ex am i nat i ons i n 1986 and 198 8, t he ex pose d sh el l i n t he t r ench es was pr epped a nd c oat ed and t he t r ench es wer e f i l l ed wi t h D ow C or ni ng 3-6548 si l i cone R T V f oam cov er ed wi t h a pr ot ect i v e l ay er of Pr om at i c l ow dens i t y si l i cone el ast om er t o t he hei ght of t he c oncr et e f l oor (El ev at i on 10'-3"). T he as sum pt i on was t hat t hese m at er i al s woul d pr ev ent wat er t hat m i ght be pr esen t on t he c o n c re te f lo o r f ro m e n te rin g th e tre n c h e s. B e f o re th e 2 0 0 6 o u ta g e th e s e m a te ria ls had not been r em ov ed f r om t he t r ench es s i nce 1988.D ur i ng t he O ct ober 2006 r ef uel i ng out age, t he f i l l er m at er i al f r om t he t wo t r ench es was r em ov ed t o al l ow i nspe ct i on of t he s hel l i n ac cor danc e wi t h co m m i t m ent num ber 27, i t em num ber 5. U pon r em ov al of t he f i l l er m at er i al , appr ox i m at el y 5" of s ta n d in g w a te r w a s d is c o v e re d in th e tre n c h lo c a te d in b a y #5. T h e tre n c h a re a in bay #17 was dam p; but no s t andi ng wat er was o bser v ed. I nv est i gat i ons conc l uded t hat t he l i kel y sou r ce o f wat er was a det er i or at ed dr ai npi pe c onnec t i on and a v oi d i n t he bot t om of t he Sub-Pi l e R oom dr ai nage t r ough, or con dens at i on wi t hi n t he dr y wel l t hat ei t her f el l t o t he f l oor or washe d down t he i nsi de of t he dr y wel l she l l t o t he c oncr et e f l oor. W at er sam pl es t aken f r om t he t r ench i n bay #5 w e re te s te d a n d d e te rm i n e d to b e n o n-a g g re s s i v e w i th p H (8.4 0 - 1 0.2 1), chl or i des (13.6 - 14.6 ppm), and s ul f at es (228 - 230 pp m). T he j oi nt bet ween t he conc r et e f l oor and t he dr y wel l she l l had no t been s eal ed t o pr ev ent wat er f r om com i ng i n co nt act wi t h t he i nner dr y wel l she l l. T he degr aded t r ough dr ai nage sy st em and t he uns eal ed gap bet ween t he c oncr et e sl ab/cur b and t he i nt er i or sur f ace of t he dr y wel l she l l was f i r st di sc ov er ed dur i ng t hi s O ct ober 2006 r ef uel i ng o u ta g e. T h is c o n d iti o n w a s e n te re d in to th e C o rre c tiv e A c tio n P ro c e s s (IR 546049). T he f ol l owi ng c or r ect i v e ac t i ons wer e t aken dur i ng t he O ct ober 2006 r ef uel i ng out age.
- W a l k d o w n s , d ra w i n g re v i e w s , t ra c e r te s ti n g a n d c h e m i s try s a m p l e s w e re per f or m ed t o i den t i f y t he p ot ent i al sour ces of wa t er i n t he t r ench es.
- St andi ng wat er was r em ov ed f r om t r ench i n bay #5 t o al l ow v i sual in s p e c tio n a n d U T e x a m in a tio n o f th e d ryw e ll s h e ll.
- A n e n g i n e e ri n g e v a l u a ti o n w a s p e rfo rm e d b y a s tru c tu ra l e n g i n e e r, re v ie w e d b y a n in d u s try c o rro s io n e x p e rt, a n d a n in d e p e n d e n t th ird p a rty ex per t t o det er m i ne t he i m pact of t he as-f ound wat er on t he c ont i nued in te g rity o f th e d ryw e ll.
- F i e l d re p a i rs/m o d i fic a ti o n s w e re i m p l e m e n te d to m i ti g a te/m i n i m i ze fu tu re 3-141 w a te r i n tru s i o n i n to th e a re a b e tw e e n th e s h e l l a n d th e c o n c re te flo o r.T h e s e re p a i rs/m o d i fi c a t i o n s c o n s i s t e d o f:
- R epai r of t he t r ough c oncr et e i n t he ar ea unde r t he r eact or v ess el to p re v e n t w a te r f ro m p o te n tia ll y m ig ra tin g th ro u g h th e c o n c re te a n d re a c h in g th e d ryw e ll s h e ll ra th e r th a n re a c h in g th e d ryw e ll sum p,
- C a u lk in g th e in te rf a c e b e tw e e n th e d ryw e ll s h e ll a n d th e d ryw e ll conc r et e f l oor/cur b t o pr ev ent wat er f r om r each i ng t he em bedded shel l , and
- G r out i ng/caul ki ng t he co ncr et e/dr y we l l shel l i nt er f aces i n t he t r ench ar eas.
- T he t r ench i n bay #5 was ex cav at ed t o unc ov er an add i t i onal 6" of t he i nt er nal dr y we l l shel l sur f ace f or i nspe ct i on a nd a l l ow U T t hi ckness m easu r em ent s t o be t aken i n an ar ea of t he s hel l t hat was e m bedded by conc r et e.
- Vi sual i nspe ct i on of t he dr y wel l she l l wi t hi n t he t r ench es was per f or m ed.
- A t ot al of 584 UT t hi ck ness m easu r em ent s wer e t aken usi ng a 6" x 6" t e mp l a t e (4 9 p o i n t s) w i t h i n t h e t w o t r e n c h e s. F o r t y-t w o (4 2) a d d i t i o n a l UT m easu r em ent s wer e t aken i n t he newl y ex pose d ar ea i n bay #5.Vi sual ex am i nat i on of t he dr y wel l she l l wi t hi n t he t wo t r ench es i ni t i al l y i dent i f i ed m i nor sur f ace r ust; wi t h wat er i n bay #5 and m oi st ur e i n bay #17. Af t er t he s u rfa c e s w e re c l e a n e d w i th a fla p p e r w h e e l (l i g h tl y to a v o i d re m o v i n g th e m e ta l) a v i s u a l e x a m i n a t i o n o f t h e s h e l l w a s c o n d u c t e d i n a c c o r d a n c e w i t h ASM E S e c tio n X l, S u b s e c tio n IW E. T h e v is u a l e x a m in a tio n id e n tifie d n o re c o rd a b le (s ig n ific a n t) c o rro s io n o n th e in n e r s u rf a c e o f s h e ll.A t ot al of 294 UT t hi ck ness m easu r em ent s wer e t aken i n t he bay #5 t r ench and 290 m easu r em ent s wer e t aken i n t he bay #17 t r ench dur i ng 2006 r ef uel i ng out age. T he r esul t s of t he m easu r em ent s i ndi cat ed t hat t he dr y wel l she l l i n t he t r ench ar eas e x per i ence d a r edu ct i on i n t he a v er age t hi ckness o f 0.038" si nce 1986. Am er G en's ev al uat i on c oncl uded t hat t he wal l t hi nni ng was a r esul t of cor r osi on on t he ex t er i or sur f ace of t he dr y wel l she l l i n t he s and bed r egi on bet ween 198 6 and 1 992 when t he s and was st i l l i n pl ace and c or r osi on was k n o w n to e x is t.An engi neer i ng ev al uat i on of t he O y st er C r eek i nner dr y wel l she l l con di t i on was p re p a re d b y a s tru c tu ra l e n g i n e e r a n d re v i e w e d b y a n i n d u s try c o rro s i o n e x p e rt and i ndepen dent t hi r d-par t y ex per t t o det er m i ne t he i m pact of t he as-f ound wat er on t he c ont i nued i nt egr i t y of t he dr y wel l she l l. T he ev al uat i on ut i l i z ed wat er chem i cal anal y si s, v i sual i nspe ct i ons and UT ex am i nat i ons. I t con cl uded t hat t he m easu r ed wat er che m i st r y v al ues and t he l ack of any i ndi cat i ons of r ebar d e g ra d a tio n o r c o n c re te s u rf a c e s p a ll in g s u g g e s t th a t th e p ro te c tiv e p a s s iv e f il m est abl i shed dur i ng co ncr et e i nst al l at i on a t t he e m bed ded st eel concr et e i nt er f ace i s s t i l l i nt act and s i gni f i cant cor r osi on of t he dr y wel l she l l woul d not be ex pect ed as lo n g a s th is b e n ig n e n v iro n m e n t is m a in ta in e d. T h e re f o re , s in c e th e c o n c re te env i r onm ent com pl i es wi t h t he EP R I con cr et e st r uct ur e gui del i nes, cor r osi on woul d not be c onsi der ed s i gni f i cant wi t hi n t he O y st er C r eek dr y wel l and t he wat er 3-142 coul d r em ai n i n co nt act wi t h t he i nt er i or dr y wel l she l l i ndef i ni t el y wi t hout hav i ng l ong t er m adver se ef f ect s.M or e sp eci f i cal l y , t he r esul t s of t hi s en gi neer i ng ev al uat i on i ndi cat e t hat no si gni f i cant cor r osi on of t he i nner sur f ace of t he em bedded dr y wel l she l l woul d be ant i ci pat ed f or t he f ol l ow i ng r easo ns:
- T he e x i st i ng w at er i n con t act wi t h t he d r y we l l shel l has b een i n con t act wi t h t he adj acen t con cr et e. T he c oncr et e i s al kal i ne whi ch i ncr ease s t he pH of t he wat er and, i n t ur n, i nhi bi t s c or r osi on. T hi s hi gh pH wat er con t ai ns l ev el s of i m pur i t i es t hat ar e si gni f i cant l y bel ow t he EP R I em bedded st eel gui del i nes a ct i on l evel r ecom m end at i ons.
- A n y n e w w a te r (s u c h a s re a c to r c o o la n t) e n te rin g th e c o n c re te-to-s h e ll in te rf a c e (n o w m in im ize d b y re p a irs/m o d ific a tio n s im p le m e n te d d u rin g th is out age) wi l l al so i ncr ease i n pH due t o i t s m i gr at i on t hr oug h an d con t act w ith th e c o n c re te c re a tin g a n o n a g g re s s iv e , a lk a li n e e n v iro n m e n t.
- M in im a l c o rro s io n o f th e w e tte d in n e r d ryw e ll s te e l s u rf a c e in c o n ta c t w ith th e c o n c re te Is o n ly e x p e c te d to o c c u r d u rin g o u ta g e s s in c e th e d ryw e ll is in e rte d w ith n itro g e n d u rin g o p e ra tio n s. E v e n d u rin g o u ta g e s , s h e ll c o r r o s i o n l o s s e s a r e e x p e c t e d t o b e i n s i g n i f i c a n t s i n c e t h e e x p o s u r e t i me t o ox y gen i s v er y l i m i t ed and t he wat er pH i s ex pect ed t o be r el at i v el y hi gh.Al so, r epai r s m odi f i cat i ons i m pl em ent ed dur i ng t he 2006 out age wi l l f ur t her m i ni m i z e ex posu r e of t he dr y wel l she l l t o ox y gen.B a s e d o n th e U T m e a s u re m e n ts ta k e n d u rin g th e 2 0 0 6 o u ta g e o f th e n e w ly e x p o s e d s h e ll a re a in B a y 5 th a t h a s n o t b e e n e x a m in e d s in c e it w a s e n c a s e d in conc r et e dur i ng I ni t i al con st r uct i on (pr e-1969), i t was d et er m i ned t hat t he t ot al m et al l ost base d on a cur r ent aver age t hi ckness m easu r em ent of 1.113" v er sus a nom i nal pl at e t hi ck ness of 1.154" i s on l y 0.041" (t ot al wal l l oss f or bot h i nsi de and out si de of t he dr y wel l she l l). Al t hough n o co nt i nui ng c or r osi on i s ex pect ed, but cons er v at i v el y ass um i ng t hat a si m i l ar wal l l oss cou l d oc cur bet ween now a nd t he end of t he per i od of ex t ended o per at i on, a m ar gi n of 336 m i l s t o t he 0.736" re q u ire d w a ll th ic k n e s s w o u ld e x is t.As f or t he 0.676" t hi ck em bedded pl at e, con ser v at i v el y ass um i ng t he pl at e has under gone c or r osi on of 0.041" t o dat e, and wi l l under go s i m i l ar wal l l oss bet ween now and t he e nd o f t he p er i od o f ext end ed o per at i on a m ar gi n of 115 m i l s aga i nst th e re q u ire d m in im u m g e n e ra l th ic k n e s s o f 0.4 7 9" re q u ire d f o r p re s s u re is pr ov i ded.T he engi neer i ng ev al uat i ons sum m ar i z ed abov e co nf i r m ed t hat t he c ondi t i on i d e n t i fi e d d u r i n g t h e 2 0 0 6 o u t a g e w o u l d n o t i m p a c t s a fe o p e r a t i o n d u r i n g t h e n e xt oper at i ng c y cl e. Al so, a co nser v at i v e pr oj ect i on (not ed abov e) of wal l l oss f or t he 1.1 5 4" a n d 0.6 7 6" th ic k e m b e d d e d s h e ll s e c tio n s in d ic a te s th a t s ig n ific a n t m a rg in i s pr ov i ded i n bot h se ct i ons t hr ough t he per i od of ex t ended o per at i on.A lth o u g h a b a s is is e s ta b li s h e d th a t o n g o in g c o rro s io n o f th e s h e ll e m b e d d e d in conc r et e sh oul d not be ex pect ed and r epai r s/m odi f i cat i ons hav e been per f or m ed to li m it o r p re v e n t w a te r f ro m re a c h in g th e in te rn a l s u rf a c e o f th e d ryw e ll s h e ll ,
3-143Am er G en has now es t abl i shed t hat t he ex i st ence of wat er i n co nt act wi t h t he i nt er nal sur f ace of t he dr y wel l she l l and c oncr et e at and be l ow t he f l oor el ev at i on wi l l be as sum ed t o be a n or m al oper at i ng env i r onm ent. Am er G en wi l l f ur t her enhanc e t he O y st er C r eek A S M E S e c tio n X l, S u b s e c tio n IW E a g in g m a n a g e m e n t p ro g ra m to re q u ire p e rio d ic i nspe ct i on of t he dr y wel l she l l sub j ect t o co ncr et e (wi t h wat er) env i r onm ent i n t he i nt er nal em bedded she l l ar ea and wat er env i r onm ent wi t hi n t he t r ench ar ea.T he s t af f r ev i ewed t he oper at i ng ex per i ence pr ov i ded i n t he LRA , PB D , and t he Decem ber 3, 2006, l et t er and i nt er v i ewed t he appl i cant's t echn i cal per sonn el. T he s t af f con cl udes t hat t he O C G S pl ant-spec i f i c op er at i ng ex per i ence i s un i que and not bounde d by i ndus t r y ex per i ence.O n th e b a s is o f its re v ie w o f th e o p e r a tin g e x p e r ie n c e a n d d is c u s s io n s w ith th e a p p lic a n t's te c h n ic a l p e rs o n n e l, th e s ta f f c o n c lu d e s th a t th e a p p li c a n t's A S M E S e c tio n X I, S u b s e c tio n IW E Pr ogr am wi l l adequa t el y m anage t he agi ng ef f ect s i dent i f i ed i n t he LRA and PBD-AM P-B.1.27 f or whi ch t hi s AM P i s c r edi t ed.Th e s t a f f d e t e r mi n e d t h a t t h e A S ME S e c t i o n X I , S u b s e c t i o n I W E P r o g r a m d e s c r i b e d i n L RA S e c tio n B.1.2 7 , is c o n s is te n t w ith th e G A L L A M P X I.S 1 , "A S M E S e c tio n X I, S u b s e c tio n IW E ,"wi t h an ex cept i on and enhanc em ent s. H owev er , oper at i ng ex per i ence i ndi cat ed t hat t he pr ogr am had not been e f f ect i v e i n m anagi ng t he ef f ect s of agi ng i n t he dr y wel l. T he dr y wel l degr adat i on is s u e in c lu d e s c o n c e rn s a s s o c ia te d w ith m o n ito rin g a n d e li m in a tin g w a te r le a k a g e , c o rro s io n in t he uppe r dr y wel l r egi on, cor r osi on i n t he f or m er san d bed r egi on, and pi t t i ng c or r osi on i n t he supp r ess i on c ham ber t or us. T he s t af f ev al uat ed t he appl i cant's Com m i t m ent 27, "AS M E S ect i on XI , Subsec t i on I W E," whi ch i ncl udes 21 i t em s. I n Sect i on 4.7.2 i n t hi s SER , t he s t af f r ev i ewed appl i cant r espo nses t o f i v e open i t em s as soc i at ed wi t h t he dr y wel l degr adat i on i ss ue. O n t he b a s is o f its e v a lu a tio n o f th e p ro g ra m d e s c rip tio n , a d d iti o n a l c o m m itm e n ts , a n d th e re s p o n s e s to th e f iv e o p e n ite m s , th e s ta f f d e te rm in e d th a t th e A S M E S e c tio n X I, S u b s e c tio n IW E P ro g ra m w il l pr ov i de as sur ance t hat t he ef f ect s of agi ng on t he dr y wel l and t or us wi l l be ade quat el y m anaged.U FS AR Suppl em ent. I n LRA Sect i on A.1.27 and l et t er s da t ed Apr i l 4, May 1, Jun e 23, D ecem ber 3, and Decem ber 15, 2006, and Febr uar y 15, 2007, t he appl i cant pr ov i ded t he U F S A R s u p p le m e n t fo r th e A S M E S e c tio n X I, S u b s e c tio n IW E P ro g ra m. T h e s ta f f re v ie w e d th is Sect i on and det er m i ned t hat t he UF SA R sup pl em ent pr ov i des an adeq uat e su m m ar y des cr i pt i on o f th e p ro g ra m , a s re q u i re d b y 1 0 C F R 5 4.2 1 (d).C oncl usi on. O n t he bas i s of i t s r ev i ew, as d i sc uss ed abov e, t he s t af f con cl udes t hat t he appl i cant has dem onst r at ed t hat t he ef f ect s of agi ng wi l l be ade quat el y m anaged so t hat i nt ended f unct i on(s) wi l l be m ai nt ai ned f or t he per i od of ex t ended o per at i on, as r equi r ed by 10 CF R 54.21(a)(3). T he s t af f al so r ev i ewed t he UF SA R sup pl em ent f or t hi s AM P and f ound t hat th i s i n fo rm a ti o n re fle c ts th e re s o l u ti o n o f th e five o p e n i te m s a n d p ro v i d e s a n a d e q u a te s u m m a ry d e s c ri p ti o n o f th e p ro g ra m , a s re q u i re d b y 1 0 C F R 5 4.2 1 (d).
3.0.3.2.24 ASME Sec t i on X I , Sub s ec t i on I W FSum m ar y of T echn i cal I nf or m at i on i n t he Appl i cat i on. I n LRA Sect i on B.1.28, t he appl i cant desc r i bed t he ex i st i ng AS M E S ect i on XI , Subsec t i on I W F P r ogr am as c onsi st ent , wi t h an e x c e p ti o n a n d e n h a n c e m e n ts , w i th G A L L A M P X I.S 3 , "A S M E S e c ti o n X I, S u b s e c ti o n IW F."
Section 3.0.3.2.27 function(s) of the structures.
Inspection of the intake canal in 2001 identified some cracks and fissures, voids, holes, and localized washout of coatings that protect embankment slopes from erosion. The degradations were evaluated and determined not to impact the intended function of the intake canal (UHS). The degradations are inspected periodically and evaluated to ensure that the intended function of the intake canal is not adversely impacted.
The staff reviewed the operating experience provided in the LRA and PBD-AMP-6.1.32, and interviewed the applicant's technical personnel to confirm that the plant-specific operating experience revealed no degradation not bounded by industry experience.
On the basis of its review of the above plant-specific operating experience and discussions with the applicant's technical personnel, the staff concludes that the applicant's RG 1 .I27 lnspection of Water-Control Structures Associated with Nuclear Power Plants Program will adequately manage the aging effects identified in the LRA for which this AMP is Credited.
UFSAR Supplement.
In LRA Section A.1.32 and letter dated March 30, 2006, the applicant provided the UFSAR supplement for the RG 1 .I27 Inspection of Water-Control Structures - Associated with Nuclear Power Plants Program. The staff determined that the information in the UFSAR supplement provides an adequate summary description of the program, as required by 10 CFR 54.21 (d). Conclusion.
On the basis of its audit and review of the applicant's RG 1 .A27 lnspection of Water-Control Structures Associated with Nuclear Power Plants Program, the staff determined that those program elements for which the applicant claimed consistency with the GALL Report are consistent.
Also, the staff reviewed the enhancements and confirmed that their implementation prior to the period of extended operation will make the AMP consistent with the GALL Report AMP to which it was compared.
The staff concludes that the applicant has demonstrated that the effects of aging will be adequately managed so that intended function(s) will be maintained consistent with the CLB for the period of extended operation, as required by 10 CFR 54.21(a)(3).
The staff also reviewed the UFSAR supplement for this AMP and conciudes that it provides an adequate summary description of the program, as required by 10 CFR 54.21(d).
3.0.3.2.27 Protective Coating Monitoring and Maintenance Program Summarv of Technical Information in the A~~lication.
In LRA Section 9.1.33, the applicant described the existing Protective Coating Monitoring and Maintenance Program as consistent with GALL AMP XI.S8, "Protective Coating Monitoring and Maintenance Program." The Protective Coating Monitoring and Maintenance Program provides for aging management of Service Level I coatings inside the primary containment and Service Level II coatings for the external drywell shell in the sandbed region. Service Level 1 coatings are used in areas where coating failure could affect the operation of post-accident fluid systems adversely and thereby impair safe shutdown.
OCGS was not originally committed to Regulatory Guide (RG) 1.54 for Service Level I coatings because the plant was licensed prior to the issuance of this RG in 1974. Currently, OCGS is committed to a modified version of this RG as described in the response to GL 98-04 and as detailed in the Exelon Quality Assurance Topical Report (QATR) NO-AA-10. Service Level II coatings provide corrosion protection and decontamination ability in areas outside of the primary containment subject to radiation exposure and radionuclide contamination.
The Protective Coating Monitoring and Maintenance Program provides for visual inspections, assessment, and repairs for any condition that adversely affects the ability of Service Level I coatings or sandbed region Service Level II coatings to function as intended.
Staff Evaluation.
During its audit and review, the staff confirmed the applicant's claim of consistency with the GALL Report.
Details of the staffs evaluation of this AMP are documented in the Audit and Review Report Section 3.0.3.2.27.
During the audit the staff requested that the applicant clarify which coatings are credited for corrosion protection of metal surfaces.
In its response, the applicant clarified that Service Level 2 coatings are used only for corrosion protection in the external drywell shell sand bed region. Similarly, while some Service Level 1 coatings are used to provide corrosion protection, the applicant does not credit them for corrosion protection for the internal surface of the dtywell shell for license renewal purposes.
An analysis has been performed which dembnstrates that the upper portion of the drywell vessel will meet ASME Code requirements for the remaining life of the plant based on corrosion rates. The corrosion of the drywell shell above the sand bed region is considered a time-limited aging analysis (TLAA) and is further described in LRA Section 4.7.2. However, Service Level 1 coatings are credited for corrosion protection for the vent header and torus. The applicant further stated that for loss of coolant accident debris generation and transport, the drywell coating is qualified for such an environment..The mass of coating released following a loss of coolant accident jet impingement was conservatively estimated at 47 pounds. No additional coating flaking was assumed due to the harsh environment because the cbating is qualified. Coating within the vent system and torus is expected to contribute 0 pounds of debris to the suction strainer load following a loss of coolant accident. However, the analysis conservatively assumed 10 pounds of debris attributed to the vent system and torus coating. The staff also requested that the applicant clarify whether any Service Level Ill coatings are credited for corrosion protection for license renewal. In its response, the applicant stated that Exelon Corporate Procedure ER-AA-330-008 in paragraph 2.7.3 defines Service Level Ill coatings as coatings used on any exposed surface area located outside containment whose failure could affect normal plant operation or orderly and safe plant shutdown adversely.
Service Level Ill coatings are also used in areas outside the reactor containment where failure could affect the safety function of a safety-related structure, system, or component adversely.
Specification SP-9000-06-004 in paragraph 3.2.l.c specifies the use of Service Level Ill coatings on structures/components subjected to a corrosive environment (e.g., liquid immersion, saltwater contact, underground burial, outdoor exposure, etc.). For license renewal Service Level Ill coatings are credited only for corrosion protection for the extemal surfaces of piping and fittings exposed to a soil (external) environment in the emergency service water (ESW) system, service water (SW) system, and roof drain and overboard discharge system (RDODS). These coatings are managed under the Buried Piping Inspection Program.
Other than the Service Levels I and II coatings discussed in PBD-AMP-B.1.33, and the Service Level Ill coatings described in response to this question no other protective coatings are credited for corrosion protection for license renewal. The staff also noted that the discussion in LRA Table 3.5.1, item 3.5.1-1 5, appears to identify a scope larger than that identified in the AMP description.
The staff requested that the applicant clarify the scope of this program. In its response, the applicant stated that the structures or components and environments "rolled-up" into LRA Table 3.5.1 item 3.5.1-1 5 (reference LRA Table 3.5.2.1 .I for primary containment) include the following:
access hatch covers - containment atmosphere (internal) downcomers - containment atmosphere drywell penetration sleeves - containment atmosphere (internal) drywell shell - containment atmosphere (internal) and indoor air (extemal) personnel airlock,equipment hatch - containment atmosphere (internal) suppression chamber penetrations - containment atmosphere (internal) suppression chamber ring girders - containment atmosphere (external) suppression chamber shell - containment atmosphere (internal) vent line, and vent header - containment atmosphere (internal) and indoor air (external) downcomers - immersed suppression chamber ring girders - immersed suppression chamber penetrations - immersed suppression chamber shell - immersed The applicant stated that for Service Level I coatings the Protective Coating Monitoring and Maintenance Program is not used to manage loss of material for access hatch covers, drywell penetration sleeves, and personnel airtock/equipment hatches exposed to a containment atmosphere (internal) environment. Accordingly, LRA Table 3.5.2.1.1 for the primary containment will be revised to delete the Protective Coating Monitoring and Maintenance Program from these component types exposed to a containment atmosphere environment.
For Service Level II coatings, the Protective Coating Monitoring and Maintenance Program is not used to manage corrosion for the vent line and vent header exposed to an indoor air (extemal) environment.
Accordingly, lRA Table 3.5.2.1 .l and fable 3.5.1, item 3.5.1-15, will be revised to delete the Protective Coating Monitoring and Maintenance Program from this component type exposed to an indoor air environment.
In its letter dated April 17, 2006, the applicant stated that LRA Tables 3.5.2.1.1 and 3.5.1 will be revised to delete the Protective Coating Monitoring and Maintenance Program from line items to manage loss of material for access hatch covers, drywell penetration sleeves, and personnel airlocklequipment hatches exposed to a containment atmosphere (internal) environment and line items to manage corrosion for the vent line and vent header exposed to an indoor air (external) environment.
The staff finds the applicant's clarifications acceptable because they defined the scope of coatings credited for corrosion protection and also defined the coatings specifically monitored and maintained by the Protective Coating Monitoring and Maintenance Program for license renewal. During its review of plant-specific operating experience related to containment degradation, the staff asked a number of questions about the implementation of the Protective Coating Monitoring and Maintenance Program for the exterior surface of the sand bed region and for the submersed interior surface of the torus. The staff's inquiries and assessments of the applicant's responses are documented in the evaluation of the applicant's ASME Section XI, Subsection IWE Program summarized in SER Section 3.0.3.2.23.
The applicant made new commitments related to monitoring of these primary containment coatings in accordance with ASME Section XI, Subsection IWE (Commitment No. 33). Subsequent to the audit, in response to RAI 4.7.2-1, by letter dated June 20,2006, the applicant provided additional information regarding the coatings credited for corrosion mitigation for primary containment and activities associated with drywell shell corrosion.
The staffs evaluation of the applicant's information and commitments is documented in SER Section 4.7.2.
Although the LRA did not identify any enhancements for the Protective Coating Monitoring and Maintenance Program, the applicant's program basis document, (PBD)-AMP-6.1.33, "OCGS Program Basis Document: Protective Coating Monitoring and Maintenance Program," Revision 0, identified the following enhancement to meet the GALL Report program elements:
Enhancement.
The applicant identified an enhancement to its program elements "parameters monitored or inspected," "detection of aging effects," and "acceptance criteria." Specifically, the enhancement stated that: The inspection of Service Level I and Service Level II protective coatings that are credited for mitigating corrosion on interior surfaces of the Torus shell and vent system, and, on exterior surfaces of the Drywell shell in the area of the sand bed region, will be consistent with ASME Section XI, Subsection IWE requirements. The staff requested that the applicant clarify what changes were necessary to make the Protective Coating Monitoring and Maintenance Program consistent with ASME Code Section XI, Subsection 1WE requirements.
In its response, the applicant stated that the requirements for coating inspections are included in OCGS specifications SP-1302-52-120, "Specification for Inspection and Localized Repair of the Torus and Vent System Coating," and 18-328227-004, "Functional RBquirements for Drywell Containment Vessel Thickness Examination." These specifications do not invoke all of the requirements of ASME Code Section XI, Subsection IWE. The following requirements will be included in these inspection specifications:
(1) Torus and vent system internal coating inspections will be per Examination Category E-A and will require VT-3 visual examinations per 1WE-3510.2.
The inspected area shall be examined (as a minimum) for evidence of flaking, blistering, peeling, discoloration, and other signs of distress. Disposition of suspect areas shall be by engineering evaluation or correction by repair or replacement in accordance with IWE-3122.
Supplemental examinations in accordance with IWE-3200 shall be performed when specified as a reswlt of engineering evaluation.
(2) Sand bed region external coating inspections will be per Examination Category E-C (augmented examination) and will require VT-1 visual examinations per IWE-3412.1.
'The inspected area shall be examined (as a minimum) for evidence of flaking, blistering, peeling, discoloration, and other signs of distress.
Disposition of suspect areas shall be by engineering evaluation or correction by repair or replacement in accordance with IWE-3122. Supplemental examinations in accordance with IWE-3200 shall be performed when specified as a result of engineering evaluation.
In its letter dated April 4, 2006, the applicant committed (Commitment No. 27) to the following: The coating inside the torus will be visually inspected in accordance with ASME Section XI, Subsection IWE, per the protective coatings program. This commitment will be performed every other refueling outage prior to and during the period of extended operation. On this basis, the staff finds this enhancement to the protective coating monitoring and maintenance program acceptable because it ensures that the requirements of ASME Code IWE related to coatings inspection will be implemented during the period of extended operation.
Operating Ex~erience.
In LRA Section 8.1.33, the applicant explained that it has successfully identified indications of age-related degradation in Service Level 1 coatings prior to the loss of intended function(s) and has taken appropriate corrective actions through evaluation or repair in accordance with the Service Level I coatings procedures and specifications.
Torus and vent header vapor space Service Level 1 coating inspections performed in 2002 found the coating in these areas in good condition. Inspection of the immersed coating in the torus identified blistering that occurred primarily in the shell invert but was also noted on the upper shell near the water line. The majority of the blisters remained intact and continued to protect the base metal. However, several blistered areas included pitting damage where the blisters were fractured. A qualitative assessment of the identified pits concluded that the measured pit depths were significantly less than the established acceptance criteria. The fractured blisters were repaired to reestablish the protective coating barrier. The Service Level II coating effort completed in the 14R refueling outage has been effective in mitigating corrosion in the sand bed area. This effort was accomplished while the vessel thickness was sufficient to satisfy ASME Code requirements, so drywell vessel corrosion in the sand bed region is no lotiger a limiting factor in plant operation; however, inspections are conducted to ensure that 'the coating remains effective.
To date, no age-related degradation has been detected in the sandbed region Service Level II coatiog. In 2003, the replacement motor for the "A recirculation motor was found to be top-coated with a nondesign basis accident qualified coating on the motor housing, end bells, and stator. Engineering analysis concluded that negligible additional suction strainer debris loading will be created by the failure of this additional unqualified coating. The staff reviewed the operating experience provided in the LRA and PBD and also interviewed the applicant's technical personnel.
The staff concludes that the plant-specific operating experience with containment degradation is unique and not bounded by industry experience.
The staff's review of operating experience led to a number of questions about the implementation of the Protective Coating Monitoring and Maintenance Program.
As a result, the staff identified 01 4.7.2-3, regarding the extent of drywell shell coated surfaces examined during each inspection. The staff's evaluation and resolution of this 01 is documented in SER Section 4.7.2. UFSAR Sup~lement.
In LRA Section A.1.33 and letters dated April 4, April 17, May 1, and June 23, 2006, the applicant provided the UFSAR supplement for the Protective Coating Monitoring and Maintenance Program. The staff reviewed this Section and determined that the UFSAR supplement provides an adequate summary description of the program, as required by 10 CFR 54.21(d).
Conclusion.
On the basis of its review, as discussed above, the staff concludes that the applicant has demonstrated that the effects of aging will be adequately managed so that the intended function(s) of primary containment will be maintained during the period of extended operation, as required by 10 CFR 54.21 (a)(3). The staff atso reviewed the UFSAR supplement for this AMP and concludes that it provides an adequate summary description of the program, as required by 10 CFR 54.21(d).
3.0.3.2.28 Electrical Cables and Connections Not Subject to 10 CFR 50.49 EQ Requirements Used in Instrument Circuits Summarv of Technical Information in the A~plication.
In LRA Section B.1.35, the applicant Sectio n 3.5.2.2.1 3-420 P W R a n d B W R C o n ta in m e n t:
- agi ng of i nacc ess i bl e co ncr et e ar eas
- cr ack s an d di st or t i on due t o i ncr ease d st r ess l ev el s f r om set t l em ent; r educ t i on of f oundat i on s t r engt h, cr ack i ng and di f f er ent i al set t l em ent due t o er osi on of por ous conc r et e su bf oundat i ons, i f not cov er ed by st r uct ur es m oni t or i ng pr ogr am
- re d u c ti o n o f s tre n g th a n d m o d u l u s o f c o n c re te s tru c tu re s d u e to e l e v a te d te m p e ra tu re
- l oss of m at er i al due t o gener al , pi t t i ng, and c r ev i ce c or r osi on
- l o s s o f p re s tre s s d u e to re l a x a ti o n , s h ri n k a g e , c re e p , a n d e l e v a te d te m p e ra tu re
- cum ul at i v e f at i gue dam age
- cr ack i ng due t o st r ess cor r osi on c r ack i ng
- cr ack i ng due t o cy cl i c l oadi ng
- l oss of m at er i al (sc al i ng, cr ack i ng, and s pal l i ng) due t o f r eez e-t haw
- cr ack i ng due t o ex pans i on and r eact i on wi t h aggr egat e and i ncr ease i n por osi t y and per m eabi l i t y due t o l each i ng of cal ci um hy dr ox i de S af et y-R el at ed a nd O t her S t r uct ur es an d C om pon ent S upp or t s:
- agi ng of st r uct ur es n ot cov er ed by st r uct ur es m oni t or i ng pr ogr am
- agi ng m anagem ent of i nacc ess i bl e ar eas
- re d u c ti o n o f s tre n g th a n d m o d u l u s o f c o n c re te s tru c tu re s d u e to e l e v a te d te m p e ra tu re
- agi ng m anagem ent of i nacc ess i bl e ar eas f or G r oup 6 s t r uct ur es
- cr acki ng d ue t o st r ess cor r osi on cr acki ng a nd l oss of m at er i al due t o pi t t i ng a nd cr evi ce cor r osi on
- agi ng of sup por t s no t cov er ed by st r uct ur es m oni t or i ng pr ogr am
- cum ul at i v e f at i gue dam age due t o cy cl i c l oadi ng Q u a li ty A s s u ra n c e f o r A g in g M a n a g e m e n t o f N o n s a f e ty-R e la te d C o m p o n e n ts St af f Ev al uat i on. For com ponent gr oups ev al uat ed i n t he G ALL R epor t , f or whi ch t he appl i cant has cl ai m ed c onsi st ency wi t h t he G ALL R epor t and f or whi ch t he G ALL R epor t r ecom m ends f ur t her ev al uat i on, t he s t af f audi t ed and r ev i ewed t he appl i cant's ev al uat i on t o det er m i ne whet her i t adequa t el y addr ess ed t he i ss ues t hat wer e f ur t her ev al uat ed. I n addi t i on, t he s t af f r ev i ewed t he a p p li c a n t's f u rth e r e v a lu a tio n s a g a in s t th e c rite ria in S R P-L R S e c tio n 3.5.2.2. D e ta il s o f th e s ta f f's a u d it a re d o c u m e n te d in th e A u d it a n d R e v ie w R e p o rt. T h e s ta f f's e v a lu a tio n o f th e a g in g e f f e c ts i s di scussed i n t he f ol l ow i ng se ct i ons.3.5.2.2.1 P W R a n d B W R C o n ta in m e n ts T he st af f r evi ew ed L R A S ect i on 3.5.2.2.1 ag ai nst t he cr i t er i a i n S R P-LR S ect i on 3.5.2.2.1, wh i ch ad dr es s es s ev er al ar ea s di s c us s ed be l ow.
3-421 Agi ng of I nacc ess i bl e C oncr et e Ar eas. I n LRA Sect i on 3.5.2.2.1.1, t he appl i cant st at ed t hat agi ng o f in a c c e s s ib le a re a s o f c o n c re te c o n ta in m e n ts , w ith re f e re n c e to th e f u rth e r e v a lu a tio n in S R P-L R S e c tio n 3.5.2.2.1.1 , is n o t a p p li c a b le b e c a u s e O C G S h a s a M a rk I s te e l c o n ta in m e n t.T he s t af f f i nds acc ept abl e t he appl i cant's ev al uat i on t hat t hi s ag i ng ef f ect i s no t appl i cabl e.C r ack s an d D i st or t i on Due t o I ncr ease d St r ess Lev el s f r om Set t l em ent; R educ t i on of Foundat i on S tre n g th , C ra c k in g a n d D iff e re n tia l S e ttle m e n t D u e to E ro s io n o f P o ro u s C o n c re te Subf oundat i ons, I f N ot C ov er ed by St r uct ur es Moni t or i ng Pr ogr am. I n LRA Sect i on 3.5.2.2.1.2, t he appl i cant st at ed t hat cr ack s an d di st or t i on of con cr et e su bf oundat i ons, wi t h r ef er ence t o t he f ur t her eval uat i on i n S R P-LR S ect i on 3.5.2.2.1.2, ar e no t app l i cabl e be cause O C G S has a M ar k I s te e l c o n ta in m e n t. T h e s ta f f f in d s a c c e p ta b le th e a p p li c a n t's e v a lu a tio n th a t th is a g in g e f f e c t is not appl i cabl e.R educ t i on of St r engt h and Modul us o f C oncr et e St r uct ur es Due t o El ev at ed T em per at ur e. T he st af f r ev i ewed LRA Sect i on 3.5.2.2.1.3 agai nst t he c r i t er i a i n SR P-LR Sect i on 3.5.2.2.1.3.I n LRA Sect i on 3.5.2.2.1.3, t he appl i cant addr ess ed r educ t i on of st r engt h and m odul us o f concr et e du e t o el evat ed t em per at ur es.S R P-L R S e c tio n 3.5.2.2.1.3 s ta te s th a t re d u c tio n o f s tre n g th a n d m o d u lu s o f c o n c re te d u e to el ev at ed t em per at ur es c oul d oc cur i n PW R and BW R con cr et e and s t eel con t ai nm ent s. T he i m pl em ent at i on of 10 CF R 50.55a and AS M E C ode Sect i on XI , Subsec t i on I W L woul d not be abl e t o i dent i f y t he r educ t i on of st r engt h and m odul us o f con cr et e due t o el ev at ed t em per at ur e.S u b s e c ti o n C C-3 4 0 0 o f A S M E C o d e S e c ti o n II I, D i v i s i o n 2 , s p e c i fie s th e c o n c re te te m p e ra tu re l i m i t s f or nor m al oper at i on or any ot her l ong-t er m per i od. T he G ALL R epor t r ecom m ends f ur t her e v a lu a tio n o f a p la n t-s p e c ific A M P if a n y p o rtio n o f th e c o n c re te c o n ta in m e n t c o m p o n e n ts ex ceed s s peci f i ed t em per at ur e l i m i t s (i.e., gener al ar ea t em per at ur e gr eat er t han 66 E C (150 E F)and l ocal ar ea t em per at ur e gr eat er t han 93 E C (200 E F)).L R A S e c ti o n 3.5.2.2.1.3 s ta te s th a t t h e n o rm a l o p e ra ti n g te m p e ra tu re i n s i d e th e p ri m a ry cont ai nm ent dr y wel l v ar i es f r om 139 E F (at el ev at i on 55') t o 256 E F (at el ev at i on 95'). T he cont ai nm ent st r uct ur e i s a BW R Mar k I st eel con t ai nm ent , whi ch i s no t af f ect ed by gener al ar ea t em per at ur e of 150 E F and l ocal ar ea t em per at ur e of 200 E F. C oncr et e f or t he r eact or pedes t al and t he dr y wel l f l oor sl ab (f i l l sl ab) ar e l ocat ed bel ow el ev at i on 55' and ar e not ex pose d t o t he e le v a te d te m p e ra tu re. T h e b io lo g ic a l s h ie ld w a ll e x te n d s f ro m e le v a tio n 3 7' 3" to 8 2' 2" a n d is ex pose d t o a t em per at ur e r ange of 139 E F t o 184 E F. T h e w a ll is a c o m p o s ite s te e l-c o n c re te cy l i nder sur r oundi ng t he r eact or v ess el f r am ed wi t h 27 i nche s de ep wi de f l ange c ol um ns c ov er ed w ith s te e l p la te o n b o th s id e s. T h e a re a b e tw e e n th e p la te s is f il le d w ith h ig h-d e n s ity c o n c re te to s a ti s fy t h e s h i e l d i n g re q u i re m e n ts. T h e s te e l c o l u m n s p ro v i d e th e i n te n d e d s tru c tu ra l s u p p o rt f unct i on and t he enc ased hi gh-dens i t y con cr et e pr ov i des shi el di ng r equi r em ent s. T he enc ased conc r et e i s no t acc ess i bl e f or i nspe ct i on. T he el ev at ed dr y wel l t em per at ur e co ncer n was e v a l u a t e d a s a p a r t o f t h e I n t e g r a t e d Pl a n t As s e s s m e n t Sy s t e m a t i c Ev a l u a t i o n Pr o g r a m (SEP)T opi c I I I-7.B. T he ev al uat i on c oncl uded t hat t he t em per at ur e woul d not adv er sel y af f ect t he st r uct ur al and shi el di ng f unct i ons o f t he w al l. T he e l evat ed d r y we l l t em per at ur e w as al so id e n tifie d a s a c o n c e rn f o r th e re a c to r b u il d in g d ryw e ll s h ie ld w a ll. F u rth e r e v a lu a tio n f o r th is w a ll i s di sc uss ed i n SE R Sect i on 3.5.2.2.2.T he s t af f f i nds acc ept abl e t he appl i cant's f ur t her ev al uat i on bec ause t he ex i st i ng el ev at ed t em per at ur e co ndi t i on i n t he dr y wel l wi l l not i m pai r t he i nt ended f unct i ons of t he s t eel c o n ta in m e n t s h e ll o r th e s h ie ld in g c o n c re te o f th e b io lo g ic a l s h ie ld w a ll.
3-422 Based on t he abov e, t he s t af f con cl udes t hat t he appl i cant has m et t he c r i t er i a of SR P-LR S e c t i o n 3.5.2.2.1.3. F o r t h o s e L R A l i n e i t e m s t h a t a p p l y t o t h i s S R P-L R s e c t i o n , t h e s t a ff det er m i ned t hat t he LRA i s c onsi st ent wi t h t he G ALL R epor t and t hat t he appl i cant has dem onst r at ed t hat t he ef f ect s of agi ng wi l l be ade quat el y m anaged so t hat t he i nt ended f unct i on(s) wi l l be m ai nt ai ned c onsi st ent wi t h t he CLB dur i ng t he per i od of ex t ended o per at i on, a s re q u i re d b y 1 0 C F R 5 4.2 1 (a)(3).L o s s o f Ma t e r i a l Du e t o Ge n e r a l , P i t t i n g a n d Cr e v i c e Co r r o s i o n. Th e s t a f f r e v i e w e d L RA Sect i on 3.5.2.2.1.4 agai nst t he c r i t er i a i n SR P-LR Sect i on 3.5.2.2.1.4.I n LRA Sect i on 3.5.2.2.1.4, t he appl i cant addr ess ed l oss of m at er i al due t o gener al , pi t t i ng, and c re v ic e c o rro s io n in s te e l e le m e n ts o f a c c e s s ib le a n d in a c c e s s ib le a re a s f o r B W R c o n ta in m e n t.S R P-LR S ect i on 3.5.2.2.1.4 st at es t hat l oss of m at er i al due t o ge ner al , pi t t i ng, and cr evi ce cor r osi on c oul d oc cur i n st eel el em ent s of acc ess i bl e and i nacc ess i bl e ar eas f or al l t y pes of PW R and BW R con t ai nm ent s. T he ex i st i ng pr ogr am r el i es o n t he AS M E S ect i on XI , Subsec t i on IW E , a n d 1 0 C F R P a rt 5 0 , A p p e n d i x J P ro g ra m s , t o m a n a g e th i s a g i n g e ff e c t. T h e G A L L R e p o rt r ecom m ends f ur t her ev al uat i on of pl ant-spec i f i c pr ogr am s t o m anage t hi s ag i ng ef f ect f or in a c c e s s ib le a re a s if c o rro s io n is s ig n ific a n t.L R A S e c tio n 3.5.2.2.1.4 s ta te s th e p o te n tia l fo r lo s s o f m a te ria l, d u e to c o rro s io n , in in a c c e s s ib le ar eas of t he c ont ai nm ent dr y wel l she l l was f i r st r ecog ni z ed i n 1980 when wat er was d i sc ov er ed c o m in g f ro m th e s a n d b e d re g io n d ra in s. C o rro s io n w a s la te r c o n f irm e d b y U T m e a s u re m e n ts ta k e n d u rin g th e 1 9 8 6 re f u e li n g o u ta g e. A s a re s u lt, s e v e ra l c o rre c tiv e a c tio n s w e re in iti a te d to det er m i ne t he ex t ent of cor r osi on, ev al uat e t he i nt egr i t y of t he dr y wel l , m i t i gat e ac cel er at ed cor r osi on, and m oni t or t he c ondi t i on of con t ai nm ent sur f aces. T he c or r ect i v e ac t i ons i ncl ude ex t ensi v e U T m easu r em ent s of t he dr y wel l she l l t hi ck ness , r em ov al of t he s and i n t he s and bed r egi on, cl eani ng and coat i ng of ex t er i or sur f aces i n ar eas wher e sa nd was r em ov ed, and an engi neer i ng ev al uat i on t o co nf i r m t he dr y wel l st r uct ur al i nt egr i t y. I n 1987, a co r r osi on m oni t or i ng pr oces s was est abl i shed f or t he dr y wel l she l l abov e t he s and bed r egi on t o ens ur e t hat t he cont ai nm ent v ess el i s c apabl e of per f or m i ng i t s i nt ended f unct i ons. El em ent s of t he pr ogr am hav e been i ncor por at ed i nt o t he AS M E S ect i on XI , Subsec t i on I W E P r ogr am and pr ov i de t he f o ll o w in g:
- per i odi c UT i nspe ct i ons of t he s hel l t hi ck ness at cr i t i cal l ocat i ons
- cal cul at i ons whi ch e st abl i sh c onse r v at i v e co r r osi on r at es
- pr oj ect i ons of t he s hel l t hi ck ness bas ed on t he c onse r v at i v e co r r osi on r at es
- d e m o n s t r a t i o n t h a t t h e mi n i m u m r e q u i r e d s h e l l t h i c k n e s s i s i n a c c o r d a n c e w i t h ASM E C ode Addi t i onal l y , t he s t af f was n ot i f i ed of t hi s po t ent i al gener i c i ss ue t hat l at er bec am e t he s ubj ect of I N 86-99 and G L 87-05.T he a ppl i cant pr ovi ded t he f ol l ow i ng su m m ar y of t he o per at i ng e x per i ence , m oni t or i ng a ct i v i t i es, and c or r ect i v e ac t i ons t aken t o ens ur e t hat t he pr i m ar y con t ai nm ent wi l l per f or m i t s i nt ended f unct i ons: D r y wel l Shel l i n t he Sand Bed R egi on. T he dr y wel l she l l i s f abr i cat ed f r om AS T M A-212-61T 3-423 G r ade B st eel pl at e. T he s hel l was c oat ed on t he i nsi de s ur f ace wi t h an i nor gani c z i nc (car bol i ne c a rb o zin c 1 1) a n d o n th e o u ts id e s u rf a c e w ith "re d le a d" p rim e r id e n tifie d a s T T-P-8 6 C T yp e I.T he r ed l ead c oat i ng c ov er ed t he ent i r e ex t er i or of t he v ess el f r om el ev at i on 8' 11.25" (f i l l sl ab l e v e l) to e l e v a ti o n 9 4' (b e l o w d ry w e l l fla n g e).T he s and bed r egi on was f i l l ed wi t h dr y san d as spe ci f i ed by AS T M 633. Leak age of wat er f r om t he s and bed dr ai ns was obs er v ed dur i ng t he 1980 and 19 83 r ef uel i ng out ages. T he appl i cant per f or m ed a s er i es o f i nv est i gat i ons t o i dent i f y t he s our ce o f t he wat er and i t s l eak pat h and conc l uded t hat t he s our ce o f wat er was f r om t he r eact or cav i t y , whi ch i s f l ooded d ur i ng r ef uel i ng out age s.W i t h t he p r esen ce of wa t er i n t he sa nd b ed r egi on, t he a ppl i cant t ook e x t ensi v e U T t hi ckness m easu r em ent s of t he d r y we l l shel l t o de t er m i ne w het her deg r ada t i on h ad o ccur r ed. T hese m easu r em ent s c or r espo nded t o kn own wat er l eaks and i ndi cat ed t hat wal l t hi nni ng had occ ur r ed i n t hi s r egi on.W ith re d u c e d th ic k n e s s re a d in g s , th e a p p li c a n t o b ta in e d a d d iti o n a l th ic k n e s s m e a s u re m e n ts to det er m i ne t he v er t i cal pr of i l e of t he t hi nni ng. I n 1986, t he appl i cant ex cav at ed t wo t r ench es i n t he dr y wel l con cr et e f l oor i n bay s #5 and #1 7 wher e t hi nni ng was m ost sev er e bec ause t he s and bed r egi on was i nacc ess i bl e at t hat t i m e. Measur em ent s t aken f r om t he ex cav at ed t r ench i ndi cat ed t hat t hi nni ng of t he em bedded she l l i n co ncr et e wer e no m or e se v er e t han t hose t aken at t he f lo o r le v e l a n d b e c a m e le s s s e v e r e a t th e lo w e r p o r tio n s o f th e s a n d b e d re g io n. C o n v e r s e ly, m easu r em ent s t aken i n ar eas wi t h no f l oor l ev el t hi nni ng s howed no si gni f i cant t hi nni ng i n t he e m b e d d e d s h e ll. A s id e f ro m U T th ic k n e s s m e a s u re m e n ts b y p la n t s ta f f , a n in d e p e n d e n t a n a ly s is by t he EP R I N D E C ent er , and t he G E U l t r a I m age I I I "C" sc an t opogr aphi cal m appi ng s y st em conf i r m ed t he U T r esul t s. T he G E ul t r a i m age r esul t s we r e use d as b asel i ne p r of i l e t o t r ack cont i nued c or r osi on.T o v a li d a te U T m e a s u re m e n ts a n d c h a ra c te rize th e f o rm o f d a m a g e a n d its c a u s e (i.e., d u e to th e p re s e n c e o f c o n ta m i n a n ts , m i c ro b i o l o g i c a l s p e c i e s , o r b o th) th e a p p l i c a n t o b ta i n e d c o re s a mp l e s o f t h e d r y w e l l s h e l l a t s e v e n l o c a t i o n s i n 1 9 8 6. Th e c o r e s a mp l e s v a l i d a t e d t h e UT m easu r em ent s and conf i r m ed t hat t he co r r osi on o f t he d r y we l l ext er i or wa s due t o t he p r esen ce of ox y genat ed wet san d and e x acer bat ed by chl or i de and sul f at e i n t he s and bed r egi on.C o n t a m i n a t e c o n c e n t r a t i o n d u e t o a l t e r n a t e w e t t i n g a n d d r y i n g o f t h e s a n d a l s o m a y h a ve c o n trib u te d to th e c o rro s io n. T h e re f o re , th e a p p li c a n t c o n c lu d e d th a t th e o p tim u m m e th o d to m i t i gat e t he c or r osi on was by r em ov al of t he s and t o br eak up t he gal v ani c c el l , r em ov al of t he cor r osi on pr oduc t f r om t he s hel l , and ap pl i cat i on of a pr ot ect i v e co at i ng.R em ov al of san d was i ni t i at ed dur i ng 1988 by t he r em ov al of she et m et al f r om ar ound t he v ent header s t o pr ov i de ac ces s t o t he s and bed f r om t he t or us r oom. D ur i ng oper at i ng c y cl e 13 s om e sand was r em ov ed and acc ess hol es c ut i nt o t he s and bed r egi on t hr ough t he s hi el d wal l. T he w o rk w a s f in is h e d in D e c e m b e r 1 9 9 2. A f te r s a n d re m o v a l, th e a p p li c a n t fo u n d th e c o n c re te s u r fac e b e l o w t h e s a n d u n fi n i s h e d w i t h i m p r o p e r p r o vi s i o n s for w a t e r d r a i n a g e. C o r r e c t i ve a c tio n s ta k e n in th is re g io n d u rin g 1 9 9 2 in c lu d e d (1) c le a n in g o f lo o s e ru s t fr o m th e d ryw e ll s h e ll f o ll o w e d b y a p p li c a tio n o f e p o x y c o a tin g a n d (2) re m o v a l o f th e lo o s e d e b ris f ro m th e c o n c re te f l oor f ol l owed by r ebui l di ng and r esha pi ng of t he f l oor wi t h epox y t o al l ow dr ai nage of any wat er t hat m ay l eak i nt o t he r egi on. U T m easu r em ent s t aken f r om t he out si de af t er cl eani ng v er i f i ed l oss of m at er i al pr oj ect i ons t hat had be en m ade bas ed on m easu r em ent s t aken f r om t he i nsi de of t he dr y wel l. T her e wer e, howev er , som e ar eas t hi nner t han pr oj ect ed, but i n al l cas es engi neer i ng anal y si s de t er m i ned t hat t he dr y wel l she l l t hi ck ness sat i sf i ed AS M E C ode 3-424 re q u ire m e n ts. T h e p ro te c tiv e c o a tin g m o n ito rin g a n d m a in te n a n c e p ro g ra m w a s re v is e d to i ncl ude m oni t or i ng of t he c oat i ngs of ex t er i or sur f aces of t he dr y wel l i n t he s and bed r egi on.T he c oat ed s ur f aces of t he f or m er san d bed r egi on wer e i nspe ct ed dur i ng r ef uel i ng out ages of 1994, 1996, 2000, and 20 04. T hese i nspe ct i ons showe d no c oat i ng f ai l ur e or si gns of det er i or at i on. T her ef or e, t he appl i cant con cl uded t hat cor r osi on i n t he s and bed r egi on had been a rre s te d a n d e x p e c te d n o f u rth e r lo s s o f m a te ria l. M o n ito rin g o f th e c o a tin g in a c c o rd a n c e w ith t he pr ot ect i v e co at i ng m oni t or i ng and m ai nt enanc e pr ogr am wi l l con t i nue t o ens ur e t hat t he cont ai nm ent dr y wel l she l l m ai nt ai ns i t s i nt ended f unct i on dur i ng t he per i od of ex t ended o per at i on.In a le tte r d a te d D e c e m b e r 3 , 2 0 0 6 , th e a p p li c a n t p ro v id e d in f o rm a tio n c o n c e rn in g th e d ryw e ll i n s p e c t i o n s a n d u l t r a s o n i c (UT) me a s u r e me n t s p e r f o r me d d u r i n g t h e 2 0 0 6 r e f u e l i n g o u t a g e. On t he bas i s of v i sual i nspe ct i ons, whi ch i ndi cat ed no v i si bl e det er i or at i on, t he appl i cant con f i r m ed t hat no f ur t her cor r osi on of t he dr y wel l she l l i s oc cur r i ng f r om t he ex t er i or of t he epox y-coat ed sand bed r egi on. O n t he bas i s of U T m easu r em ent s of t he dr y wel l she l l i n t he s and bed r egi on f r om i nsi de t he dr y wel l , t he appl i cant con f i r m ed t hat cor r osi on on t he ex t er i or sur f aces of t he dr y wel l she l l i n t he s and bed r egi on has been a r r est ed. O n t he bas i s of U T m easu r em ent s t aken i n t he t r ench es i n dr y wel l bay s nu m ber #5 and #17, t he appl i cant con cl uded t hat wal l t hi nni ng of appr ox i m at el y 0.038" had t aken pl ace i n eac h t r ench si nce 1986.O n t he bas i s of 106 UT m easu r em ent s t aken on t he out si de of t he dr y wel l i n t he s and bed r egi on i n 2006, t he appl i cant det er m i ned t hat t he m easu r ed l ocal t hi ck ness i s gr eat er t hat t he l ocal acc ept ance cr i t er i a of 0.409" f or pr ess ur e and 0.536" f or l ocal buc ki ng. T he appl i cant dec i ded t hat , si nce t he 106 U T m easu r em ent s c oul d not be c or r el at ed di r ect l y wi t h t he c or r espo ndi ng 1 9 9 2 U T d a ta , it w o u ld e n h a n c e th e A S M E S e c tio n X I, S u b s e c tio n IW E P ro g ra m (B.1.2 7) to r equi r e U T m easu r em ent s of t he l ocal l y t hi nned ar eas i n 2008 and per i odi cal l y dur i ng t he per i od of ex t ended o per at i on.T he s t af f r ev i ewed t he appl i cant's op er at i ng ex per i ence and pr opos ed agi ng m anagem ent act i v i t i es t o addr ess degr adat i on of t he pr i m ar y con t ai nm ent dr y wel l ar ea i n t he f or m er san d bed re g io n a s p a rt o f its e v a lu a tio n o f th e A S M E S u b s e c tio n IW E P ro g ra m. T h e s ta f f p re v io u s ly i dent i f i ed, i n t he SE R , dat ed August 18, 2006, f i v e O I s an d f ound t hat t he appl i cant had no t pr ov i ded s uf f i ci ent i nf or m at i on t o co ncl ude t hat t he ef f ect s of agi ng f or t he pr i m ar y con t ai nm ent woul d be ad equat el y m anaged dur i ng t he per i od of ex t ended o per at i on. T he appl i cant pr ov i ded addi t i onal i nf or m at i on i n t he l et t er s da t ed Decem ber 3 and 1 5, 2006, and Febr uar y 15, 2007, i ncl udi ng addi t i onal com m i t m ent s (C om m i t m ent N o.27), t o t he s t af f f or r ev i ew. U pon f ur t her ev al uat i on, t he s t af f con cl udes t hat t he ef f ect s of agi ng wi l l be ade quat el y m anaged so t hat t he i nt ended f unct i ons wi l l be m ai nt ai ned dur i ng t he per i od of ex t ended o per at i on as r equi r ed by 10 CF R 54.21(a)(3). T he s t af f's r esol ut i on of t he open i t em s i s do cum ent ed i n Sect i on 4.7.2 of t h i s S E R.D r y we l l S hel l A bove S and B ed R egi on. T he U T i nvest i gat i on p hase (198 6 t hr oug h 19 91) al so i den t i f i ed l oss of m at er i al due t o cor r osi on i n t he u ppe r r egi ons o f t he d r y we l l shel l. T hese r egi ons w er e ha ndl ed se par at el y f r om t he sa nd b ed r egi on b ecau se of t he si gni f i cant di f f er ence i n co r r osi on r at e and p hy si cal di f f er ence i n des i gn. C or r ect i v e ac t i on f or t hese r egi ons pr ov i ded a c o rro s i o n a l l o w a n c e b y d e m o n s tra ti n g , t h ro u g h a n a l y s i s , t h a t t h e o ri g i n a l d ry w e l l d e s i g n p re s s u re w a s c o n s e rv a tiv e. A m e n d m e n t 1 6 5 to th e O C G S te c h n ic a l s p e c ific a tio n s re d u c e d th e d ryw e ll d e s ig n p re s s u re f ro m 6 2 p s ig to 4 4 p s ig. T h e n e w d e s ig n p re s s u re c o u p le d w ith m e a s u re s to pr ev ent wat er i nt r usi on i nt o t he gap bet ween t he dr y wel l she l l and t he c oncr et e wi l l al l ow t he upp er por t i on o f t he d r y we l l t o m eet A S M E C ode r equ i r em ent s.
3-425 O rig in a ll y, th e k n o w le d g e o f th e e x te n t o f c o rro s io n w a s b a s e d o n U T m e a s u re m e n ts c o m p le te ly ar ound t he i nsi de of t he dr y wel l at sev er al el ev at i ons. At eac h el ev at i on, a bel t-l i ne s weep t ook r eadi ngs on as l i t t l e as 1-i nch cent er s wher ev er t hi ck ness cha nged be t ween s ucc ess i v e nom i nal 6-i n c h c e n te rs. 6" b y 6" g ri d s th a t e x h i b i te d th e w o rs t m e ta l l o s s a ro u n d e a c h e l e v a ti o n w e re e s ta b li s h e d b y th is a p p ro a c h a n d in c lu d e d in th e d ryw e ll c o rro s io n in s p e c tio n p ro g ra m. A s e xp e ri e n c e i n c re a s e d w i t h e a c h d a t a c o l l e c t i o n c a m p a i g n , o n l y g ri d s s h o w i n g e vi d e n c e o f a c h a n g e w e re re ta in e d in th e in s p e c tio n p ro g ra m. A d d iti o n a l a s s u ra n c e o f th e a d e q u a c y o f th is in s p e c tio n p la n w a s o b ta in e d b y a c o m p le te ly ra n d o m ize d in s p e c tio n o f 4 9 g rid s s h o w in g th a t a ll i nspe ct i on l ocat i ons sat i sf i ed AS M E C ode r equi r em ent s. Ev al uat i on of U T m easu r em ent s t aken t hr ough 20 00 c oncl uded t hat cor r osi on no l onger occ ur s at t wo (2) el ev at i ons, t he t hi r d el ev at i on u n d e r g o e s a c o r r o s i o n r a t e o f 0.6 mi l s p e r y e a r , a n d t h e f o u r t h 1.2 mi l s p e r y e a r. Th e r e c e n t UT m easu r em ent s (2004) con f i r m ed t hat t he c or r osi on r at e co nt i nues t o dec l i ne. T he 2 el ev at i ons t hat pr ev i ousl y ex hi bi t ed no i ncr ease i n co r r osi on c ont i nue t he t r end t o no c or r osi on i ncr ease.T he r at e of cor r osi on f or t he t hi r d el ev at i on dec r ease d f r om 0.6 t o 0.4 m i l s pe r y ear. T he r at e of c o r r o s i o n f o r t h e f o u r t h e l e v a t i o n d e c r e a s e d f r o m 1.2 t o 0.7 5 mi l s p e r y e a r. A f t e r e a c h UT ex am i nat i on c am pai gn, an eng i neer i ng anal y si s i s pe r f or m ed t o ens ur e t he r equi r ed m i ni m um th ic k n e s s th ro u g h th e p e rio d o f e x te n d e d o p e ra tio n. T h u s , c o rro s io n o f th e d ryw e ll s h e ll is cons i der ed a TLA A f ur t her des cr i bed i n SE R Sect i on 4.7.2.In a le tte r d a te d D e c e m b e r 3 , 2 0 0 6 , th e a p p li c a n t p ro v id e d in f o rm a tio n c o n c e rn in g th e d ryw e ll i n s p e c t i o n s a n d u l t r a s o n i c (UT) me a s u r e me n t s p e r f o r me d d u r i n g t h e 2 0 0 6 r e f u e l i n g o u t a g e. On t he bas i s of U T m easu r em ent s t aken at f our el ev at i on of t he dr y wel l , t he appl i cant det er m i ned th a t:
- N o o b s e rva b l e c o rr o s i o n i s o c c u rr i n g a t e l e va t i o n s 5 1' 1 0" a n d 6 0' 1 0".
- A si ngl e l ocat i on at el ev at i on 50' 2" con t i nues t o ex per i ence m i nor cor r osi on at a r at e of 0.6 6 m i l s/y e a r.
- T h e c o rro s io n a t e le v a tio n 8 7' 5" is s ta tis tic a ll y i n s ig n ific a n t.T he appl i cant per f or m ed UT m easu r em ent s at t wo l ocat i ons at t he c i r cum f er ent i al wel d t hat j oi ns t he bot t om sph er i cal pl at es a nd t he m i ddl e sp her i cal pl at es a t el ev at i on 23' 6". T he appl i cant det er m i ned t hat t he l oss of m at er i al i n t he t hi nner pl at es i s i nsi gni f i cant and i s bo unded b y cor r osi on ex per i ence at ot her ar eas of t he dr y wel l abov e t he s and bed r egi on. T he appl i cant det er m i ned t hat t he t hi ck er pl at es h av e not ex per i ence d any obs er v abl e co r r osi on.T he appl i cant per f or m ed UT m easu r em ent s at t wo l ocat i ons at t he c i r cum f er ent i al wel d t hat j oi ns t he t r ansi t i on pl at es, whi ch a r e r ef er r ed t o as t he k nuck l e pl at es, bet ween t he c y l i nder and t he sphe r e at el ev at i on 71' 6". T he appl i cant det er m i ned t hat t he l oss of m at er i al i n t he t hi nner pl at es i s i nsi gni f i cant and i s bo unded b y cor r osi on ex per i ence d i n ot her ar eas of t he dr y wel l abov e t he sand bed r egi on. T hr ough i t s i nspe ct i ons, t he appl i cant i dent i f i ed s om e r educ ed t hi ck ness i n t he th ic k e r p la te th a t c o u ld b e a ttrib u te d to s e v e ra l fa c to rs , in c lu d in g v a ria tio n s in o rig in a l p la te t hi ck ness , r em ov al of m at er i al dur i ng or i gi nal j oi nt pr epar at i on, and c or r osi on. T he appl i cant st at ed t hat even i f t he l oss of m at er i al i s at t r i but ed e nt i r el y t o cor r osi on, t he a v ai l abl e t hi ckness m ar gi n i s ad equat e t o ens ur e t hat t he i nt ended f unct i on of t he dr y wel l i s no t i m pact ed bef or e t he n e x t in s p e c tio n p la n n e d f o r 2 0 1 0.
3-426 T h e a p p li c a n t c o m m itte d to ta k e U T m e a s u re m e n ts in 2 0 1 0 a t e le v a tio n s 2 3' 6" a n d 7 1' 6" to c o n f irm th a t c o rro s io n is b o u n d e d b y a re a s o f th e u p p e r d ryw e ll th a t a re m o n ito re d p e rio d ic a ll y. If cor r osi on i n t hese l ocat i ons i s gr eat er t han ar eas m oni t or ed i n t he uppe r dr y wel l , t he appl i cant wi l l per f or m U T i nspe ct i on on a f r equenc y of ev er y ot her r ef uel i ng out age (C om m i t m ent 27 I t em n u m b e rs 1 0 a n d 1 1 i n A m e rG e n L e tt e r N o. 2 1 3 0-0 6-2 0 3 5 8 d a te d J u l y 7 , 2 0 0 6).T he appl i cant con cl uded t hat t he c or r ect i v e ac t i ons t aken and c ont i nued m oni t or i ng of t he dr y wel l f or l oss m at er i al t hr ough t he AS M E S ect i on XI , Subsec t i on I W E, Pr ot ect i v e C oat i ng M o n ito rin g a n d M a in te n a n c e , a n d 1 0 C F R P a rt 5 0 , A p p e n d ix J P ro g ra m s p ro v id e re a s o n a b le assur ance t hat l oss of m at er i al i n i nacce ssi bl e ar eas o f t he d r y we l l wi l l be d et ect ed p r i or t o a l oss o f a n i n te n d e d fu n c ti o n. O b s e rv e d c o n d i ti o n s w i th p o te n ti a l i m p a c t o n a n i n te n d e d fu n c ti o n a re e v a lu a te d o r c o rre c te d in a c c o rd a n c e w ith th e c o rre c tiv e a c tio n p ro c e s s. T h e A S M E S e c tio n X I, Subsect i on I W E, Pr ot ect i v e C oat i ng Moni t or i ng and M ai nt enanc e, and 10 C FR Par t 50, A p p e n d ix J P ro g ra m s a re e v a lu a te d in S E R S e c tio n 3.0. T he s t af f not ed t hat t he appl i cant had no t addr ess ed agi ng m anagem ent of t he por t i on of t he dr y wel l she l l em bedded i n t he dr y wel l con cr et e f l oor. T hi s ar ea i s i nacc ess i bl e f or i nspe ct i on but p o t e n t i a l l y s u b j e c t t o w e t t i n g o n b o t h i n s i d e a n d o u t s i d e s u rfa c e s. D u ri n g t h e a u d i t , t h e s t a ff re q u e s te d th a t th e a p p li c a n t s u b m it i ts A M R f o r th is in a c c e s s ib le p o rtio n o f th e d ryw e ll s h e ll.T he appl i cant st at ed t hat t he em bedded por t i on of t he dr y wel l she l l i s ex em pt f r om v i sual ex am i nat i on i n ac cor danc e wi t h I W E-1232. Pr ess ur e t est i ng i n ac cor danc e wi t h 10 CFR Par t 50, Appendi x J, T y pe A t est i s c r edi t ed f or m anagi ng agi ng ef f ect s of i nacc ess i bl e por t i ons of t he d ryw e ll s h e ll c o n s is te n t w ith th e G A L L R e p o rt.T he appl i cant i dent i f i ed t hat t he G ALL R epor t , Vol um e 2, i t em I I.B1.1-2, AM P col um n st at es t hat l oss of m at er i al due t o co r r osi on i s no t si gni f i cant i f t he f ol l owi ng c ondi t i ons ar e sa t i sf i ed:
- conc r et e m eet i ng t he s peci f i cat i ons of AC I 318 or 349 an d us e of t he gui danc e of 201.2R f or con t ai nm ent she l l or l i ner
- conc r et e m oni t or i ng t o ens ur e t hat i t i s f r ee of cr ack s pr ov i di ng pat hs f or wat er see page t o t he s ur f ace of t he c ont ai nm ent she l l or l i ner
- agi ng m anagem ent of t he m oi st ur e bar r i er , at t he j unct i on wher e t he s hel l or l i ner b e c o m e s e m b e d d e d , i s s u b j e c t t o a g i n g man a g e m e n t i n a c c o r d a n c e w i t h ASM E S e c tio n X I, S u b s e c tio n IW E re q u ire m e n ts
- pr om pt cl ean-up of wat er pondi ng on t he c ont ai nm ent con cr et e f l oor when det ect ed If a n y o f th e s e c o n d itio n s c a n n o t b e s a tis f ie d , a p la n t-s p e c if ic A M P f o r c o r r o s io n is n e c e s s a r y.T h e a p p li c a n t in d ic a te d th a t its A M R re s u lts s a tis f y th e s e re q u ire m e n ts a n d th a t a p la n t-s p e c ific AM P i s no t r equi r ed f or cor r osi on of t he em bedded dr y wel l she l l. T he c oncr et e m eet s t he r ecom m endat i ons of AC I 318 an d t he gui danc e of AC I 201.2R. T he dr y wel l con cr et e f l oor wi l l be m oni t or ed f or cr ack s un der t he St r uct ur es Moni t or i ng Pr ogr am. O C G S desi gn does not i ncl ude a m o i s tu re b a rri e r; h o w e v e r, t h e d e s i g n p ro v i d e s a 9-i n c h h i g h c u rb (m i n i m u m) a ro u n d th e e n ti re dr y wel l f l oor (ex cept at t wo t r ench es) t o pr ev ent any con t act bet ween wat er acc um ul at ed on t he f l oor and t he dr y wel l she l l. T he c ur b i s c onsi der ed par t of t he dr y wel l con cr et e f l oor and in s p e c te d f o r c ra c k in g u n d e r th e S tru c tu re s M o n ito rin g P ro g ra m. T h e d ryw e ll f lo o r is d e s ig n e d to 3-427 sl ope away f r om t he dr y wel l she l l t owar ds t he dr y wel l sum p f or pr oper dr ai nage. T he s um p l ev el i s m o n i to re d i n th e m a i n c o n tro l ro o m i n a c c o rd a n c e w i th te c h n i c a l s p e c i fic a ti o n s , a n d a c ti o n s a re t aken t o ens ur e t hat t echn i cal spe ci f i cat i ons l i m i t s ar e not v i ol at ed. I f t he s um p f i l l s an d t he o v e rf lo w le a k ra te c a n n o t b e m o n ito re d , a p la n t s h u td o w n w il l b e re q u ire d to re g a in le a k ra te m oni t or i ng ca pab i l i t y and t o de t er m i ne t he so ur ce of t he l eak.T he appl i cant f ur t her st at ed t hat dur i ng t he i nv est i gat i on per i od t o det er m i ne t he ex t ent of cor r osi on i n t he ex t er i or sur f aces of t he s and bed r egi on t wo t r ench es wer e ex cav at ed i n t he d ryw e ll c o n c re te f lo o r to e x p o s e th e e m b e d d e d d ryw e ll s h e ll s o th a t U T th ic k n e s s m e a s u re m e n ts c o u l d b e t a k e n f r o m i n s i d e t h e d r y w e l l i n t h e s a n d b e d r e g i o n. V i s u a l i n s p e c t i o n a n d UT m e a s u re m e n ts d id n o t id e n tify c o rro s io n a s a c o n c e rn o n th e e x p o s e d e m b e d d e d d ryw e ll s h e ll i nsi de t he dr y wel l wi t hi n t he ex cav at ed t r ench es. T he t wo t r ench es wer e se al ed wi t h an el ast om er t o pr ev ent wat er i nt r usi on i nt o t he em bedded she l l. Pr i or t o t he per i od of ex t ended o p e ra tio n a o n e-tim e v is u a l i n s p e c tio n o f th e e m b e d d e d d ryw e ll s h e ll w ith in th e tw o tre n c h e s w il l be per f or m ed by r em ov al of t he s eal ant and ex posu r e of t he em bedded she l l. I nspe ct i on and acc ept ance cr i t er i a wi l l be i n ac cor danc e wi t h I W E. I f v i sual i nspe ct i on r ev eal s c or r osi on t hat c o u l d i m p a c t d r y w e l l i n t e g r i t y , c o r r e c t i ve a c t i o n s w i l l b e i n i t i a t e d i n a c c o r d a n c e w i t h t h e c o r r e c t i ve act i on pr oces s t o ens ur e t hat t he dr y wel l r em ai ns c apabl e of per f or m i ng i t s i nt ended f unct i on.Fol l owi ng t hese i nspe ct i ons, t he t r ench es wi l l be r esea l ed f or con t i nued pr ot ect i on of t he em bedded she l l. I n addi t i on, one-t i m e U T m easu r em ent s wi l l be t aken and c or r ect i v e ac t i ons i ni t i at ed i n ac cor danc e wi t h t he c or r ect i v e ac t i on pr oces s t o ens ur e t hat t he dr y wel l i s c apabl e of per f or m i ng i t s i nt ended f unct i on.In its le tte r d a te d A p ril 4 , 2 0 0 6 , th e a p p li c a n t c o m m itte d (C o m m itm e n t N o. 2 7) to th e f o ll o w in g: A v i sual ex am i nat i on of t he dr y wel l she l l i n t he dr y wel l f l oor i nspe ct i on ac ces s t r ench es wi l l be p e rf o rm e d to a s s u re th a t th e d ryw e ll s te e l re m a in s in ta c t. If d e g ra d a tio n is id e n tifie d , th e d ryw e ll s h e ll c o n d iti o n w il l b e e v a lu a te d a n d c o rre c tiv e a c tio n s ta k e n a s n e c e s s a ry. T h e s e s u rf a c e s w il l ei t her be i nspe ct ed as par t of t he s cope of t he AS M E S ect i on XI , Subsec t i on I W E P r ogr am , or t hey wi l l be r est or ed t o t he or i gi nal des i gn c onf i gur at i on wi t h co ncr et e or ot her sui t abl e m at er i al t o pr event m oi st ur e col l ect i on i n t hese ar eas. In a d d iti o n to its p re v io u s c o m m itm e n t to p e rf o rm o n e-tim e v is u a l e x a m in a tio n s o f th e d ryw e ll shel l i n t he ar eas ex pose d by t he t r ench es i n t he bot t om of t he dr y wel l , i n i t s l et t er dat ed Ma y 1 , 2 0 0 6 , t h e a p p l i c a n t c o mmi t t e d (Co mmi t me n t No. 2 7) t o t a k i n g o n e-t i me UT m easu r em ent s t o co nf i r m t he adeq uacy of t he s hel l t hi ck ness i n t hese ar eas, pr ov i di ng f ur t her a s s u ra n c e th a t th e d ryw e ll w il l re m a in c a p a b le o f p e rf o rm in g its in te n d e d f u n c tio n. T h is c o m m itm e n t w il l b e p e rf o rm e d p rio r to th e p e rio d o f e x te n d e d o p e ra tio n. T he appl i cant al so n ot ed t hat t he i nacc ess i bl e dr y wel l she l l i n t he s and bed r egi on bec am e a c c e s s ib le (f ro m th e o u ts id e s u rf a c e) a f te r re m o v a l o f s a n d in 1 9 9 2. T h e in te rf a c e o f th e s h e ll a n d th e s a n d b e d f lo o r w a s c le a n e d , c o a te d , a n d s e a le d w ith s il ic o n s e a la n t. T h e p e rio d ic coat i ng i nspe ct i on h as no t i den t i f i ed a ny coat i ng d egr ada t i on a t t he sh el l-concr et e i nt er f ace in d ic a tin g c o rro s io n in th e e m b e d d e d p o rtio n o f th e s h e ll.In a le tte r d a te d D e c e m b e r 3 , 2 0 0 6 , th e a p p li c a n t p ro v id e d in f o rm a tio n c o n c e rn in g th e d ryw e ll i nspe ct i ons and ul t r ason i c (U T) m easu r em ent s pe r f or m ed dur i ng t he 2006 r ef uel i ng out age.D ur i ng t he out age, t he appl i cant r em ov ed f i l l er m at er i al f r om t he t wo t r ench es t o al l ow i nspe ct i on of t he em bedded she l l and f ound wat er i n one o f t he t r ench es. T he appl i cant con cl uded t hat t he l i kel y sou r ce o f wat er was a det er i or at ed dr ai npi pe c onnec t i on and a v oi d i n t he bot t om of t he Sub-Pi l e R oom dr ai nage t r ough, or con dens at i on wi t hi n t he dr y wel l t hat ei t her f el l t o t he f l oor or 3-428 w a s h e d d o w n th e In s id e o f th e d ryw e ll s h e ll to th e c o n c re te f lo o r. T h e a p p li c a n t d re w w a te r f ro m th e tre n c h a n d d e te rm in e d th e w a te r to b e n o n-a g g re s s iv e w ith pH (8.40 - 10.21), chl or i des (13.6- 14.6ppm), and s ul f at es (228 - 230 pp m). T he appl i cant f ound t hat t he j oi nt bet ween t he c oncr et e f l oor and t he dr y wel l she l l had no t been s eal ed t o pr ev ent wat er f r om com i ng i n co nt act wi t h t he i nner dr y wel l she l l. T he appl i cant f i r st di sc ov er ed t he degr aded t r ough dr ai nage s y st em and t he uns eal ed gap bet ween t he c oncr et e sl ab c ur b and t he i n t e r i o r s u r fac e o f t h e d r y w e l l s h e l l d u r i n g t h e 2 0 0 6 r e fue l i n g o u t a g e. T h e fol l o w i n g c o r r e c t i ve act i ons wer e t aken dur i ng t he r ef uel i ng out age.
- W a lk d o w n s , d ra w in g re v ie w s , tra c e r te s tin g , a n d c h e m is try s a m p le s w e re p e rf o rm e d to i den t i f y t he p ot ent i al sour ces of wa t er i n t he t r ench es.
- St andi ng wat er was r em ov ed f r om t r ench t o al l ow v i sual i nspe ct i on and U T ex am i nat i on o f th e d ryw e ll s h e ll.
- An engi neer i ng ev al uat i on was per f or m ed t o det er m i ne t he i m pact of t he as-f ound wat er o n th e c o n tin u e d In te g rity o f th e d ryw e ll.
- Fi el d r epai r s an d m odi f i cat i ons wer e i m pl em ent ed t o m i t i gat e and m i ni m i z e f ut ur e wat er i nt r usi on i nt o t he ar ea bet ween t he s hel l and t he c oncr et e f l oor. T hese r epai r s an d m o d i fi c a t i o n s c o n s i s t e d o f:
- R epai r of t he t r ough c oncr et e I n t he ar ea unde r t he r eact or v ess el t o pr ev ent wat er f r om pot ent i al l y m i gr at i ng t hr ough t he c oncr et e and r each i ng t he dr y wel l she l l r at her t han r each i ng t he dr y wel l sum p.
- C aul ki ng t he i nt er f ace bet ween t he dr y wel l she l l and t he dr y wel l con cr et e f l oor and c u rb to p re v e n t w a te r f ro m re a c h in g th e e m b e d d e d s h e ll.
- G r out i ng a nd ca ul ki ng t he co ncr et e/dr y we l l shel l i nt er f aces i n t he t r ench ar eas.
- T he t r ench wa s excav at ed t o un cover an a ddi t i ona l 6" of t he i nt er nal dr y we l l shel l sur f ace f o r in s p e c tio n a n d a ll o w U T th ic k n e s s m e a s u re m e n ts to b e ta k e n in a n a re a o f th e s h e ll t hat was e m bedded by con cr et e.
- Vi sual i nspe ct i on of t he dr y wel l she l l wi t hi n t he t r ench es was per f or m ed.
- A t ot al of 58 4 UT t hi c k ne s s m ea s ur ement s we r e t ak en wi t hi n t he t wo t r en c he s. Fo r t y-t wo (42) addi t i onal U T m easu r em ent s wer e t aken i n t he newl y ex pose d ar ea i n bay #5.T he appl i cant det er m i ned t hat t he m easu r ed wat er che m i st r y v al ues and t he l ack of any i n d i c a t i o n s o f r e b a r d e g r a d a t i o n o r c o n c r e t e s u r fac e s p a l l i n g s u g g e s t t h a t t h e p r o t e c t i ve p a s s i ve f il m e s ta b li s h e d d u rin g c o n c re te in s ta ll a tio n a t th e e m b e d d e d s te e l/c o n c re te in te rf a c e is s til l i nt act. T he appl i cant con cl uded t hat si gni f i cant cor r osi on of t he dr y wel l she l l woul d not be ex pect ed as l ong as t he beni gn env i r onm ent i s m ai nt ai ned.T he appl i cant st at ed t hat i t wi l l f ur t her enhanc e t he O y st er C r eek AS M E S ect i on XI , Subsec t i on IW E a g in g m a n a g e m e n t p ro g ra m to re q u ire p e rio d ic in s p e c tio n o f th e d ryw e ll s h e ll s u b je c t to conc r et e (wi t h wat er) env i r onm ent i n t he i nt er nal em bedded she l l ar ea and wat er env i r onm ent 3-429 wi t hi n t he t r ench ar ea. Speci f i c en hanc em ent s ar e:
- U T t hi ck ness m easu r em ent s wi l l be t aken f r om out si de t he dr y wel l i n t he s and bed r egi on dur i ng t he 2008 r ef uel i ng out age on t he l ocal l y t hi nned ar eas ex am i ned dur i ng t he O c to b e r 2 0 0 6 re f u e li n g o u ta g e. T h e lo c a ll y th in n e d a re a s a re d is trib u te d b o th v e rtic a ll y and ar ound t he per i m et er of t he dr y wel l i n al l t en bay s s uch t hat pot ent i al cor r osi on of t he dr y wel l she l l woul d be de t ect ed.
- St ar t i ng i n 2010, dr y wel l she l l U T t hi ck ness m easu r em ent s wi l l be t aken f r om out si de t he dr y wel l i n t he s and bed r egi on i n t wo bay s pe r out age, suc h t hat i nspe ct i ons wi l l be p e rf o rm e d in a ll 1 0 b a ys w ith in a 1 0-ye a r p e rio d. T h e tw o b a ys w ith th e m o s t lo c a ll y t hi nned ar eas (bay #1 and bay #13) wi l l be i nspe ct ed i n 2010. I f t he UT ex am i nat i ons y i el d unac cept abl e r esul t s, t hen t he l ocal l y t hi nned ar eas i n al l 10 bay s wi l l be i nspe ct ed i n t he r ef uel i ng out age t hat t he unac cept abl e r esul t s ar e i dent i f i ed.
- Per f or m v i sual i nspe ct i on of t he dr y wel l she l l i nsi de t he t r ench i n bay #5 and bay #17 an d ta k e U T m e a s u re m e n ts in s id e th e s e tre n c h e s in 2 0 0 8 a t th e s a m e lo c a tio n s e x a m in e d in 2006. R epeat (bot h t he UT and v i sual) i nspe ct i ons at r ef uel i ng out ages dur i ng t he per i od of ex t ended o per at i on unt i l t he t r ench es a r e r est or ed t o t he or i gi nal des i gn c onf i gur at i on usi ng co ncr et e or ot her sui t abl e m at er i al t o pr event m oi st ur e col l ect i on i n t hese ar eas.
- Per f or m v i sual i nspe ct i on of t he m oi st ur e bar r i er bet ween t he dr y wel l she l l and t he conc r et e f l oor/cur b, i nst al l ed i nsi de t he dr y wel l dur i ng t he O ct ober 2006 r ef uel i ng out age, i n ac cor danc e wi t h AS M E S ect i on Xl , Subsec t i on I W E dur i ng t he per i od of ex t ended oper at i on.Af t er eac h i nspe ct i on, t he appl i cant wi l l ev al uat e U T t hi ck ness m easu r em ent s r esul t s an d com par e t hem wi t h pr ev i ous U T t hi ck ness m easu r em ent s. I f uns at i sf act or y r esul t s ar e i dent i f i ed, th e n a p p li c a n t w il l i n iti a te , a s n e c e s s a ry, a d d iti o n a l c o rre c tiv e a c tio n s to e n s u re th e d ryw e ll s h e ll i nt egr i t y i s m ai nt ai ned t hr oughou t t he per i od of ex t ended o per at i on.In its le tte r d a te d D e c e m b e r 3 , 2 0 0 6 , th e a p p li c a n t s ta te d th a t L R A T a b le 3.5.1 w il l b e re v is e d to add t he f ol l owi ng Pl ant Speci f i c Not es t o T abl e 3.5.2.1.1: 10.
W at er env i r onm ent f or t he dr y wel l she l l and t he r ei nf or ced conc r et e sl ab (f i l l sl ab) was i dent i f i ed dur i ng 2006 i n t wo t r ench es i nsi de t he dr y wel l con cr et e f l oor. T he s our ce o f w a te r is m o s t li k e ly f ro m le a k a g e o f tre a te d w a te r f ro m p la n t e q u ip m e n t in s id e th e d ryw e ll.C h e m ic a l te s ts o f w a te r s a m p le s in c o n ta c t w ith c o n c re te a n d th e d ryw e ll s h e ll in d ic a te t hat t he wat er i s no t aggr ess i v e (pH = 8.40 -10.21), (C hl or i de =13.6 - 14.6 ppm), and (S u l fa te = 2 2 8 - 2 3 0 p p m). 1 1.
T h e m o is tu re b a rrie r w a s a d d e d in 2 0 0 6 to s e a l th e ju n c tio n o f th e e m b e d d e d d ryw e ll shel l and t he c oncr et e cu r b i nsi de t he dr y wel l. T he abs ence of t he m oi st ur e bar r i er was id e n tifie d a s a p o te n tia l p a th o f w a te r f o u n d in c o n ta c t w ith th e in n e r d ryw e ll s h e ll e m b e d d e d i n th e c o n c re te d ry w e l l flo o r (fi l l s l a b). 12.
10 CF R Par t 50, Appendi x J, i s no t a cr edi t ed agi ng m anagem ent pr ogr am bec ause t he m o is tu r e b a r r ie r is n o t th e p r im a r y c o n ta in m e n t p r e s s u r e b o u n d a r y. 1 3.
O ys te r C re e k o p e ra tin g e x p e rie n c e id e n tifie d th a t th e re in f o rc e d c o n c re te (f il l s la b) is 3-430subj ect t o pondi ng of wat er on t he f l oor and wat er i nt r usi on i nt o t he s ubsu r f ace of f i l l sl ab.T he s our ce o f wat er i s m ost l i kel y f r om l eaka ge of t r eat ed wat er f r om pl ant equi pm ent in s id e th e d ryw e ll. C h e m ic a l te s ts o f w a te r s a m p le s in c o n ta c t w ith th e c o n c re te in d ic a te t hat t he wat er i s no t aggr ess i v e (pH = 8.40 - 10.21, C hl or i de =13.6 - 14.6 ppm , and Sul f at e = 2 28 - 230 pp m). T he r ei nf or ced conc r et e (f i l l sl ab) i s m oni t or ed f or l oss of m at er i al (spel l i ng, sc al i ng), cha nge i n m at er i al pr oper t i es (l oss of bond) and c r ack i ng due t o co r r osi on of em bedded st eel. T he agi ng ef f ect s an d t he agi ng m anagem ent pr ogr am ar e co nsi st ent wi t h N U R EG-1801, l i ne i t em I I I.A1-4, f or non-aggr ess i v e gr oundwat er e n v iro n m e n t.T he s t af f con cl udes t hat t he appl i cant wi l l det er m i ne, bas ed on t he r esul t s of t he i nspe ct i on of t he t wo t r ench es, t he c ondi t i on of t he i nacc ess i bl e por t i on of t he dr y wel l she l l em bedded i n t he dr y wel l con cr et e f l oor pr i or t o t he per i od of ex t ended o per at i on, and t hat cor r ect i v e ac t i ons wi l l be t aken as n eces sar y i f degr adat i on i s f ound. T he s t af f f i nds t he appl i cant's ap pr oach t o agi ng m a n a g e m e n t o f th e in a c c e s s ib le p o rtio n o f th e d ryw e ll s h e ll e m b e d d e d in th e d ryw e ll c o n c re te f l oor acc ept abl e.I n i t s ev al uat i on of t he appl i cant's ASM E S ect i on XI , Subsec t i on I W E P r ogr am t he s t af f ev al uat ed t he degr adat i on hi st or y of t he appl i cant's c ont ai nm ent and t he adeq uacy of i t s ag i ng m a n a g e m e n t c o m m itm e n ts f o r th e p e rio d o f e x te n d e d o p e ra tio n. F iv e o p e n ite m s a n d th e ir r esol ut i ons ar e di sc uss ed i n det ai l i n SE R Sect i on 4.7.2. Based on t he appl i cant's pr opos ed agi ng m anagem ent act i v i t i es f or t he per i od of ex t ended o per at i on, t he s t af f f i nds t hat t he appl i cant has m et t he c r i t er i a of SR P-LR Sect i on 3.5.2.2.1.4 f or f ur t her ev al uat i on and dem onst r at ed t hat t he ef f ect s of agi ng wi l l be ade quat el y m anaged so t hat t he i nt ended f unct i ons w i l l b e m a i n ta i n e d d u ri n g th e p e ri o d o f e x te n d e d o p e ra ti o n , a s re q u i re d b y 1 0 C F R 5 4.2 1 (a)(3).L o s s o f P r e s t r e s s Du e t o Re l a x a t i o n , S h r i n k a g e , Cr e e p , a n d E l e v a t e d Te mp e r a t u r e. L RA S ect i on 3.5.2.2.1.5 st at es t hat l oss of pr est r ess of concr et e con t ai nm ent s i s not app l i cabl e si nce O C G S has a Mar k I st eel con t ai nm ent. T he s t af f f i nds acc ept abl e t he appl i cant's ev al uat i on t hat th is a g in g e f f e c t is n o t a p p li c a b le s in c e O C G S h a s a M a rk I s te e l c o n ta in m e n t.C u m u la tiv e F a tig u e D a m a g e. L R A S e c tio n 3.5.2.2.1.6 s ta te s th a t fa tig u e is a T L A A , a s d e f in e d in 1 0 CFR 5 4.3. Ap p l i c a n t s mus t e v a l u a t e TL AAs i n a c c o r d a n c e w i t h 1 0 CFR 5 4.2 1 (c)(1). SER Se c t i o n 4.6 d o c u m e n t s t h e s t a f f's r e v i e w o f t h e a p p l i c a n t's e v a l u a t i o n o f t h i s TL AA.C ra c k in g D u e to S tre s s C o rro s io n C ra c k in g (S C C). T h e s ta f f re v ie w e d L R A S e c tio n 3.5.2.2.1.7 agai nst t he c r i t er i a i n SR P-LR Sect i on 3.5.2.2.1.7.I n LRA Sect i on 3.5.2.2.1.7, t he appl i cant addr ess ed c r ack i ng of st ai nl ess st eel penet r at i on s l e e v e s , p e n e t r a t i o n b e l l o w s , a n d d i s s i mi l a r me t a l w e l d s d u e t o S CC.SR P-LR Sect i on 3.5.2.2.1.7 st at es t hat cr ack i ng due t o SC C of st ai nl ess st eel penet r at i on sl eev es, penet r at i on bel l ows, and di ss i m i l ar m et al wel ds c oul d oc cur i n al l t y pes of PW R and BW R con t ai nm ent s. C r ack i ng due t o SC C al so c oul d oc cur i n st ai nl ess st eel v ent l i ne bel l ows f or BW R con t ai nm ent s. T he ex i st i ng pr ogr am r el i es o n t he AS M E S ect i on XI , Subsec t i on I W E and 1 0 C F R P a rt 5 0 , A p p e n d i x J P ro g ra m s to m a n a g e th i s a g i n g e ff e c t. T h e G A L L R e p o rt r ecom m end s f ur t her eval uat i on o f add i t i ona l app r opr i at e exam i nat i ons a nd e v al uat i ons t o de t ect t hese agi ng ef f ect s f or st ai nl ess st eel penet r at i on s l eev es, penet r at i on bel l ows an d di ss i m i l ar m et al we l ds, and st ai nl ess st eel v ent l i ne b el l ow s.
Sectio n 4.7.2 4-41 4.7.1.3.4 Concl usi on O n t he bas i s of i t s r ev i ew, as d i sc uss ed abov e, t he s t af f con cl udes t hat t he appl i cant has dem onst r at ed, pur suan t t o 10 CFR 54.21(c)(1)(i i), t hat , f or t he heat er bay cr ane TLA A, t he ana l y ses ha v e be en p r oj ect ed t o t he e nd o f t he p er i od o f ext end ed o per at i on. T he st af f al so conc l udes t hat t he UF SA R sup pl em ent con t ai ns a n appr opr i at e su m m ar y des cr i pt i on of t he act i v i t i es f or m anagi ng t he ef f ect s of agi ng and t he T LAA ev al uat i on, as r equi r ed by 1 0 C F R 5 4.2 1 (d).
4.7.2 Dr y w el l Cor r os i on 4.7.2.1 Su m m ar y o f Te ch ni ca l I nf or m at i on i n t he Appl i ca t i on I n LRA Sect i on 4.7.2, t he appl i cant sum m ar i z ed t he ev al uat i on of dr y wel l cor r osi on f or t he per i od of ex t ended o per at i on. T he Mar k I con t ai nm ent des i gn i ncl udes an ann ul us (ex pans i on gap)bet ween t he c ont ai nm ent and t he pr i m ar y con t ai nm ent shi el d wal l. T he pot ent i al f or degr adat i on of t he co nt ai nm ent r esul t s f r om cond i t i ons t hat al l ow t he i nt r odu ct i on o f wa t er i nt o t he a nnu l us.T hi s po t ent i al f or cor r osi on was f i r st r ecog ni z ed when wa t er was n ot i ced com i ng f r om t he s and bed dr ai ns i n 1980. C or r osi on was l at er con f i r m ed by ul t r ason i c t hi ck ness m easu r em ent s t aken i n 1986. C or r ect i v e ac t i on i ncl uded es t abl i shi ng a m i ni m um she l l t hi ck ness. T hi s was acc om pl i shed by dem onst r at i ng t hr ough an al y si s t hat t he or i gi nal dr y wel l des i gn pr ess ur e was cons er v at i v e. T he pl ant t echn i cal spe ci f i cat i ons wer e am ended t o r educ e t he dr y wel l des i gn pr ess ur e f r om 62 t o 44 ps i g. T he new de si gn pr ess ur e, cou pl ed wi t h t he m easu r es t o pr ev ent wat er i nt r usi on i n t he gap bet ween t he c ont ai nm ent v ess el and t he s hi el d wal l con cr et e, al l ow t he dr y wel l v ess el t o m eet AS M E C ode r equi r em ent s f or t he r em ai ni ng 40-y ear pl ant l i f e. Anal y si s of t he m i ni m um wal l t hi ck ness of t he c ont ai nm ent v ess el sat i sf i es t he c r i t er i a of 10 CF R 54.3(a) and i s t h u s a TL AA.R e g a rd in g its a n a ly s is , th e a p p li c a n t s ta te d th a t s e v e ra l c o rre c tiv e a c tio n s h a v e b e e n ta k e n to ensu r e m i ni m um wal l t hi ck ness es a r e m ai nt ai ned, i ncl udi ng r em ov al of san d f r om t he s and bed re g io n to b re a k u p g a lv a n ic a c tio n , re m o v a l o f th e c o rro s io n p ro d u c t fr o m th e c o n ta in m e n t v e s s e l, a n d a p p li c a tio n o f a p ro te c tiv e c o a tin g. In a d d iti o n , O C G S p e rf o rm s a m o n ito rin g p ro g ra m to ensu r e t hat cor r osi on m i t i gat i on m easu r es ar e ef f ect i v e an d t he r equ i r ed m i ni m um wa l l t hi ckness is m a in ta in e d. T h e A S M E S e c tio n X I, S u b s e c tio n IW E P ro g ra m e n s u re s th a t th e re d u c tio n in v ess el t hi ck ness wi l l not adv er sel y af f ect t he abi l i t y of t he dr y wel l t o per f or m i t s s af et y f unct i on.I nspe ct i ons cond uct ed s i nce 1992 de m onst r at e t hat as a r esul t of cor r ect i v e ac t i ons t he cor r osi on r at es a r e v er y l ow or i n so m e ca ses hav e been ar r est ed. C oat ed dr y wel l sur f aces do not sho w si gns of or det er i or at i on. D r y wel l v ess el wal l t hi ck ness m easu r em ent s i ndi cat e a subs t ant i al m ar gi n t o t he m i ni m um wal l t hi ck ness , ev en when p r oj ect ed t o t he y ear 2029 u si ng c o n s e rv a tiv e e s tim a te s o f th e c o rro s io n ra te s. C o n tin u e d a s s e s s m e n t o f th e o b s e rv e d d ryw e ll v e s s e l th ic k n e s s e n s u re s th a t tim e ly a c tio n c a n b e ta k e n to c o rre c t d e g ra d a tio n th a t c o u ld le a d to lo s s o f th e in te n d e d f u n c tio n. T h e A S M E S e c tio n X I, S u b s e c tio n IW E P ro g ra m a s s u re s th a t th e d ryw e ll v e s s e l th ic k n e s s w il l not be r educ ed t o l ess t han t he m i ni m um r equi r ed v al ue i n any f ut ur e oper at i on. T her ef or e, t he e f f e c ts o f lo s s o f m a te ria l o n th e in te n d e d f u n c tio n o f th e d ryw e ll w il l b e a d e q u a te ly m a n a g e d in acc or danc e wi t h 10 CFR 54.21(c)(1)(i i i) f or t he per i od of ex t ended o per at i on.T h e A S M E S e c tio n X I, S u b s e c tio n IW E P ro g ra m a s s u re s th a t th e d ryw e ll v e s s e l th ic k n e s s w il l not be r educ ed t o l ess t han t he m i ni m um r equi r ed v al ue i n any f ut ur e oper at i on. T her ef or e, t he 4-42 e f f e c ts o f lo s s o f m a te ria l o n th e in te n d e d f u n c tio n o f th e d ryw e ll w il l b e a d e q u a te ly m a n a g e d in acc or danc e wi t h 10 CFR 54.21(c)(1)(i i i) f or t he per i od of ex t ended o per at i on.
4.7.2.2 St af f Eva l ua t i on T he s t af f's r ev i ew of LR A S ect i on 4.7.2 i dent i f i ed ar eas i n whi ch a ddi t i onal i nf or m at i on was n e c e s s a r y t o c o m p l e t e t h e r e v i e w o f d r y w e l l c o r r o s i o n. Th e a p p l i c a n t r e s p o n d e d t o t h e s t a f f's RAI as di s c us s ed be l ow.
4.7.2.2.1 D r y wel l C or r osi on Sam pl i ng I n R AI 4.7.2-1 dat ed Mar ch 1 0, 2006, t he s t af f r eques t ed t hat t he appl i cant pr ov i de i nf or m at i on conc er ni ng t he dr y wel l cor r osi on ex i st i ng dur i ng t he l at e 1980s , and t he new c or r osi on f ound dur i ng t he s ubse quent i nspe ct i ons, pr ov i de t he pr oces s us ed t o es t abl i sh c onf i denc e t hat t he s a m p li n g d o n e f o r id e n tifyin g th e a re a s o f c o rro s io n h a s b e e n a d e q u a te. I n i t s r espo nse dat ed Apr i l 7, 2006, t he appl i cant em phas i z ed t hat i t em pl oy s a r obus t pr oces s of est abl i shi ng c onf i denc e t hat t he nat ur e and l ocat i ons of sam pl i ng done and t he ar eas cons i der ed f o r id e n tifyin g th e a re a s o f c o rro s io n h a v e b e e n a d e q u a te. T h e a p p li c a n t s ta te d th a t th e e le m e n ts o f p ro c e s s w e re d e v e lo p e d o v e r s e v e ra l y e a rs a n d w e re d e f in e d in s e v e ra l te c h n ic a l d o c u m e n ts subm i t t ed t o t he N R C i n t he 1 990 s. T he a ppl i cant sum m ar i z ed t he p r ocess a s f ol l ow s:I nspe ct i ons usi ng UT t hi ck ness m easu r em ent s wer e co nduc t ed dur i ng r ef uel i ng out ages and ou t ages of oppor t uni t y bet ween 198 6 and 1 989 t o es t abl i sh a nd c h a r a c t e r i z e t h e e x t e n t o f c o r r o s i o n o f t h e d r y w e l l s h e l l. Th e i n i t i a l UT m easu r em ent s wer e not bas ed on a sam pl i ng pr oces s. I nst ead, t he m easu r em ent s wer e t aken i n ar eas t hat cor r espo nd t o l ocat i ons wher e wat er le a k a g e w a s o b s e rv e d f ro m th e s a n d b e d re g io n d ra in s. T h e U T m e a s u re m e n ts we r e t hen expande d ar oun d t he d r y we l l per i m et er and v er t i cal l y t o est abl i sh lo c a tio n s a f f e c te d b y c o rro s io n. A p p ro x im a te ly 1 0 0 0 U T th ic k n e s s m e a s u re m e n ts w e re ta k e n to id e n tify th in n e s t a re a s. In a d d iti o n , c o re s a m p le s o f th e d ryw e ll s h e ll wer e t aken at sev en l ocat i ons, bel i ev ed t o be r epr esen t at i v e of gener al wast age, t o con f i r m U T r esul t s.Based on t he r esul t s of t hese i nspe ct i ons, el ev at i ons 11'-3" , 50'-2" , and 87'-5" wer e i dent i f i ed f or m oni t or i ng. El ev at i on 11'-3" , whi ch c or r espo nds t o t he s and bed r egi on, sho wed t he hi ghes t cor r osi on r at e i n 1987 (up t o 39.1 +/- 3.4 m i l s pe r ye a r) b a s e d o n 1 9 8 6 , a n d 1 9 8 7 U T m e a s u re m e n ts. T h e h ig h ra te o f c o rro s io n in t he s and bed r egi on pr om pt ed c or r ect i v e ac t i on of a phy si cal nat ur e t hat i nv ol v ed r em ov al of t he s and. As a r esul t , cor r osi on of t he dr y wel l she l l i n t he s and bed re g io n w a s a d d re s s e d d iff e re n tly th a n th e u p p e r re g io n o f th e d ryw e ll.T he m ost cr i t i cal r egi on af f ect ed by t he c or r osi on-r el at ed m et al l oss was t he s and bed r egi on of t he dr y wel l she l l. T he appl i cant pr ov i ded a b r i ef hi st or y of t he UT m easu r em ent s t aken and act i ons t aken t o pr event or m i t i gat e cor r osi on i n t hi s ar ea a s f ol l ow s:T h e h ig h ra te o f c o rro s io n in th e s a n d b e d re g io n w a s a ttrib u te d to g a lv a n ic cor r osi on of t he dr y wel l she l l cau sed by wat er r et ai ned i n t he s and bec ause of l ack of pr oper dr ai nage. T o r educ e t he c or r osi on r at e, O y st er C r eek i ni t i at ed s ev er al c or r ec t i v e a c t i on s as de s c r i be d i n t he r es po ns e t o i t em (c) be l ow.E v a lu a tio n o f th e s e c o rre c tiv e a c tio n s c o n c lu d e d th a t th e m o s t e f f e c tiv e a c tio n to 4-43 r educ e t he c or r osi on r at e i s t o r em ov e t he s and f r om t he s and bed r egi on and p ro te c t th e d ryw e ll s h e ll f ro m a d d iti o n a l c o rro s io n b y a p p ly in g a p ro te c tiv e c o a tin g. Loca t i on of t he UT m easu r em ent s was not bas ed on a sam pl i ng pr oces s. I nst ead, t he l ocat i ons wer e bas ed on UT m easu r em ent s t aken at al l acc ess i bl e l ocat i ons t hat cor r espo nd t o t he s and bed r egi on f r om i nsi de t he dr y wel l t o es t abl i sh t he th in n e s t a re a. A f te r th e s a n d w a s re m o v e d in 1 9 9 2 , a n d p rio r to c o a tin g th e s h e ll , t hi ck ness m easu r em ent s wer e t aken i n eac h of t he 10 b ay s, f r om out si de t he d ryw e ll , to e s ta b li s h th e m in im u m g e n e ra l a n d lo c a l th ic k n e s s o f th e th in n e d s h e ll.T he m easu r em ent s f r om i nsi de t he dr y wel l sho wed t hat t he m i ni m um gener al t hi ckness o f t he sa nd b ed r egi on i s 0.800 i nche s, and t he m i ni m um l ocal t hi ckness i s 0.618 i nche s. T he m easu r em ent s f r om out si de t he dr y wel l i n t he s and bed r egi on sh ow ed t hat t he m i ni m um t hi ckness i s gen er al l y gr eat er t han 0.800 i nche s.T h e re w e re l o c a l a re a s w h e re th e th i c k n e s s i s l e s s th a n 0.8 0 0 i n c h e s. H o w e v e r, t he m i ni m um aver age t hi ckness i n t hese ar eas i s gr eat er t han 0.736 i nche s, wh i ch i s r equ i r ed f or sat i sf y i ng A S M E C ode r equ i r em ent s. T he m i ni m um l ocal t hi ckness m easu r ed f r om out si de t he s and bed r egi on i s 0.603 i nche s. C onsi der i ng m easu r em ent and i nst r um ent acc ur aci es, i t i s c oncl uded t hat l ocat i ons ex am i ned f r om i nsi de t he dr y wel l r epr esen t t he c ondi t i on of t he s and bed r egi on.T he r esul t s of t hese m easu r em ent s an d su bseq uent anal y si s, whi ch c onsi der ed al l des i gn bas i s l oads and l oad c om bi nat i ons, con f i r m ed t hat t he " as f ound" cond i t i on of t he dr y wel l she l l t hi ck ness sat i sf i es ASM E S ect i on I I I m i ni m um th ic k n e s s re q u ire m e n ts. A d d iti o n a l th ic k n e s s m e a s u re m e n ts ta k e n a t a ll acc ess i bl e l ocat i ons (t ot al of 19) f r om i nsi de t he dr y wel l i n 1992, 1994, and 19 96 show n o co r r osi on, or no s i gni f i cant cor r osi on (see T abl e-2). I n addi t i on, i nspe ct i on of t he pr ot ect i v e co at i ng on e x t er i or sur f aces of t he dr y wel l she l l i n t he sand bed r egi on, ev er y ot her r ef uel i ng out age, sho ws no degr adat i on of t he c o a ti n g o r th e u n d e rl y i n g s h e l l." A gener al t r end of t he av er age c or r osi on f ound i n t he s and-pock et ar ea as pr ov i ded by t he appl i cant i s s hown i n Fi gur e 3 of t he r espo nse. Fi gur e 3 s hows t he gr owt h of cor r osi on f or t he l ocat i on of t hi nnes t wal l t hi ck ness. I t sho ws an av er age t hi ck ness of 0.87 i nch i n D ecem ber 1986 a n d a p p r o xi m a t e l y 0.8 i n c h i n D e c e m b e r 1 9 9 2. A ft e r 1 9 9 2 (i.e., a ft e r t h e a p p l i c a t i o n o f an e p o xy coat i ng t o t he s hel l i n t he s and poc ket ar ea), t he av er age t hi ck ness appear s t o hav e st abi l i z ed at 0.8 i nch base d on t he r eadi ngs t aken i n 1994 and 199 6. Af t er 1996, t he appl i cant ex t r apol at ed t he t hi ck ness t o r em ai n as 0.8 i nch dur i ng t he c ur r ent l i cens i ng per i od and dur i ng t he per i od of ex t ended o per at i on.T he appl i cant pr ov i ded a s t at us o f cor r osi on of t he uppe r r egi on, abov e t he s and bed r egi on, and not ed t hat bas ed on t he r esul t s of appr ox i m at el y 1000 UT m easu r em ent s, t he appl i cant c o n tin u e d to m o n ito r e le v a tio n s 5 0' 2" a n d 8 7' 5" in th e re g io n s a b o v e th e s a n d b e d re g io n. A t hi r d el ev at i on, 51' 10" , was a dded t o t he s cope of i nspe ct i on af t er i t was d et er m i ned t hat t he s u p p l i e d p l a t e t h i c k n e s s i s s l i g h t l y l e s s t h a n t h e a d j a c e n t 5 0' 2". F o r e a c h e l e v a t i o n , UT m easu r em ent s s pace d appr ox i m at el y 1 i nch wi t hi n a 6-i nch by 6-i nch ar r ay wer e t aken f r om i nsi de t he dr y wel l ar ound t he ent i r e per i m et er of eac h el ev at i on. Engi neer i ng ev al uat i on of t he U T r esul t s c oncl uded t hat m oni t or i ng of 12 l ocat i ons woul d r epr esen t t he dr y wel l she l l con di t i on and pr ov i de r easo nabl e as sur ance t hat si gni f i cant cor r osi on woul d be de t ect ed bef or e a l oss of an i nt ended f unct i on. T he appl i cant con cl uded t hat t hi s i s be caus e t he 12 l ocat i ons, as d esc r i bed bel ow, wer e se l ect ed c onsi der i ng t he degr ee of dr y wel l she l l t hi nni ng and t he m i ni m um r equi r ed t hi ckness t o sat i sf y A S M E st r ess r equ i r em ent s:
4-44
- s e v e n lo c a tio n s a t 5 0' 2",
- t hr ee l ocat i ons at el ev at i on 87' 5" , and
- tw o lo c a tio n s a t e le v a tio n 5 1' 1 0". T hese l ocat i ons ar e i nspe ct ed f r om t he i nsi de of t he dr y wel l she l l on a f r equenc y of ev er y ot her r ef uel i ng out age.I n r espo nse t o an ea r l i er con cer n f r om t he s t af f r egar di ng whet her t he i nspe ct ed l ocat i ons r e p r e s e n t t h e c o n d i t i o n o f t h e e n t i r e d r y w e l l , i n 1 9 9 0 , Ge n e r a l P u b l i c Ut i l i t i e s Co r p o r a t i o n (GP U)p re p a re d a n e w ra n d o m U T in s p e c tio n p la n (a ls o k n o w n a s a u g m e n te d in s p e c tio n) d e s ig n e d to a d d re s s th e c o n c e rn. T h e p la n w a s b a s e d o n a n o n p a ra m e tric s ta tis tic a l a p p ro a c h u s in g a ttrib u te sam pl i ng t hat ass um es n o pr i or kno wl edge of t he di st r i but i on of cor r osi on abov e t he s and bed r egi on. I t con si st ed of r andom U T t est i ng of 57 pl at es u si ng t he 6-i nch by 6-i nch gr i d. T he a p p li c a n t-e s ta b li s h e d a c c e p ta n c e c rite ria w e re th a t th e m e a n a n d lo c a l th ic k n e s s o f th e s h e ll e q u a ls o r e x c e e d s th e re q u ire d m in im u m th ic k n e s s , p lu s a c o rro s io n a ll o w a n c e n e c e s s a ry to r each t he nex t i nspe ct i on.T he appl i cant not ed t hat t he i nspe ct i on r esul t s us i ng t he new r andom i nspe ct i on pl an c onf i r m ed t hat pr ev i ousl y m oni t or ed l ocat i ons bound t he c ondi t i on of t he dr y wel l abov e t he s and bed re g i o n , e xc e p t o n e l o c a t i o n a t e l e va t i o n 6 0' 1 0". T h i s e l e va t i o n w a s a d d e d t o e l e va t i o n s 5 0' 2", 51' 10" , and 87' 5" and ha s be en m oni t or ed ev er y ot her r ef uel i ng out age s i nce i dent i f i ed i n 1992.Af t er des cr i bi ng t he bas i s f or t he ear l i er st af f acc ept ance of t he appl i cant's pr ogr am t he a p p li c a n t p ro v id e d th e re s u lts o f f u rth e r in s p e c tio n s: D u rin g a re c e n t w a lk d o w n o f th e to ru s b y th e s ys te m e n g in e e r, w a te r w a s f o u n d in t hr ee 5-gal l on c ont ai ner s t hat wer e i nst al l ed t o co l l ect wat er l eaka ge f r om t he s a n d b e d d ra i n s. T w o o f th e 3 c o n ta i n e rs w e re fo u n d n e a rl y fu l l. T h e th i rd cont ai ner was a ppr ox i m at el y hal f f ul l. I nspe ct i on of t he dr ai n l i nes showe d t hat t he l i nes wer e dr y and t hat wat er i n t he c ont ai ner s was not due t o a wat er l eaka ge.T he c ont ai ner s wer e cl osed suc h t hat t hei r ov er f l ow was u nl i kel y as c onf i r m ed by n o w a te r p o n d in g o n th e f lo o r. T h u s , th e a p p li c a n t c o n c lu d e d w ith re a s o n a b le a s s u ra n c e th a t th e v o lu m e o f w a te r w a s li m ite d to what i s c ont ai ned i n t he c ont ai ner s, and at t em pt ed t o j ust i f y t hat t he s m al l am ount of wat er was not expect ed t o ha v e si gni f i cant i m pact on t he d r y we l l shel l and on t he co at i ng o f t he sh el l , si nce t he c oat i ng i s de si gned f or a su bm er ged env i r onm ent. T he appl i cant not ed t hat f ur t her i nspe ct i on of t he s and bed r egi on c oat i ng c onduc t ed i n 2004 di d not i ndi cat e co at i ng degr adat i on or i ndi cat i ons of dr y wel l she l l cor r osi on. Si m i l ar l y , U T ex am i nat i ons on t he uppe r r egi on of t he dr y wel l sho wed a dec r ease i n t he c or r osi on r at e si nce t he pr ev i ous i nspe ct i on i n 2000. T hus, t he appl i cant con cl uded t hat t he s m al l v ol um e of wat er f ound i n t he bot t l es s houl d not hav e cr eat ed a n e n v iro n m e n t th a t w o u ld re s u lt i n s ig n ific a n t c o rro s io n to th e d ryw e ll s h e ll. O C G S I ssue R epo r t N o. 004 703 25 w as i ssued , i n acco r dan ce w i t h t he co r r ect i v e act i on p r ocess, t o i nv est i gat e t he s our ce o f wat er and ev al uat e i t s i m pact on t he dr y wel l she l l. Based on t he di sc uss i on abov e, and as i ndi cat ed i n t he t abl es s uppl i ed i n r espo nse t o i t em (d) bel ow, t he appl i cant con cl uded t hat dr y wel l cor r osi on i s ef f ect i v el y m anaged bot h dur i ng t he c ur r ent and p ro p o s e d re n e w e d te rm s o f p l a n t o p e ra ti o n. T h e m o n i to re d l o c a ti o n s u n d e r th e c u rre n t t e rm w e re subj ect ed t o ex t ensi v e U T m easu r em ent s c onduc t ed ov er sev er al y ear s. T he s t af f f i nds t he sam pl i ng m et hodol ogy t o i dent i f y t hese l ocat i ons, and t he r esul t s of i nspe ct i ons, acc ept abl e f or 4-45 t he c ur r ent t er m. T he appl i cant st at ed t hat t he s am e l ocat i ons wi l l be i nspe ct ed dur i ng t he ex t ended p er i od of oper at i on.In s u m m a ry, th e a p p li c a n t e m p h a s ize d th a t O C G S h a s c o n d u c te d e x te n s iv e e x a m in a tio n s to id e n tify th e c a u s e o f d ryw e ll c o rro s io n , e m p lo ye d a ro b u s t s a m p li n g p ro c e s s , q u a n tifie d w ith re a s o n a b le a s s u ra n c e th e e x te n t o f d ryw e ll s h e ll th in n in g d u e to c o rro s io n , a n d a s s e s s e d its im p a c t o n th e d r yw e ll's s tr u c tu r a l in te g r ity.I n addi t i on, t he appl i cant st at ed t hat wat er i nt r usi on i nt o t he gap bet ween t he dr y wel l she l l and t he dr y wel l shi el d wal l was i dent i f i ed as t he c ause f or cor r osi on. C or r ect i v e ac t i ons hav e been ta k e n to m iti g a te c o rro s io n in th e s a n d b e d re g io n a n d in th e u p p e r re g io n o f th e d ryw e ll.C o r r o s i o n o f t h e d r y w e l l s h e l l i n t h e s a n d b e d r e g i o n h a s b e e n a r r e s t e d. T h e s e a c t i o n s a l s o h a ve ef f ect i v el y r educ ed t he r at e of cor r osi on t o a neg l i gi bl e am ount i n t he uppe r r egi on, as dem onst r at ed by U T t hi ck ness m easu r em ent s. O C G S and i t s c onsu l t ant s pe r f or m ed s t r ess and buckl i ng a nal y ses con si der i ng a l l desi gn-basi s l oad s and l oad com bi nat i ons. T he r esul t s of t hese anal y ses i ndi cat ed t hat buc kl i ng c ont r ol s t he m i ni m um dr y wel l she l l t hi ck ness es i n t he s and bed r egi on, whi l e ar eas abov e t he s and bed r egi on ar e co nt r ol l ed by acc i dent pr ess ur e m em br ane st r ess es. I n bot h ca ses , t he m i ni m um m easu r ed dr y wel l she l l t hi ck ness sat i sf i ed AS M E C ode S ect i on I I I r equ i r em ent s.
O p e n Ite m 4.7.2-1.1: L o c a tio n o f U T M e a s u re m e n ts T he s t af f's r ev i ew of t he appl i cant's r espo nse, i ncl udi ng Fi gur e 3 and T abl es 1 and 2, det er m i ned t hat U T m easu r em ent s t aken i n t he s pher i cal por t i on of t he dr y wel l she l l adequa t el y r epr esen t t he uppe r sph er i cal ar ea. H owev er , t her e wer e no m easu r em ent s t aken i n t he l ower por t i on of t he s pher i cal ar ea abov e t he s and-pock et ar ea. T o ens ur e t hat t he s pher i cal por t i on of t he dr y wel l she l l i s pr oper l y r epr esen t ed i n t he dat abas e, addi t i onal U T m easu r em ent s t aken appr ox i m at el y at or abov e t he j unct i on of t he 0.722 i nch and 1.154 i nch t hi ck pl at es wou l d be desi r abl e. Li kewi se, addi t i onal U T m easu r em ent s s houl d be t aken on t he c y l i ndr i cal por t i on of t he dr y wel l she l l at about 71' 6" (i.e. at t he j unct i on of t he 0.640 i nch pl at e and t he t hi ck ened p la te in th e k n u c k le a re a). T h e s ta f f re q u e s te d th a t th e a p p li c a n t c la rif y i ts U T s a m p li n g p la n in c o n te x t o f th e e n tire d ryw e ll s h e ll a s s e s s m e n t.I n i t s r espo nse dat ed J une 20, 2006, t he appl i cant st at ed:A r ev i ew of t he dr y wel l f abr i cat i on and i nst al l at i on det ai l s s how t hat t he wel ds t hat at t ach t he 0.770 i nche s (t he c or r ect t hi ck ness i s 0.770 i nche s, not 0.722 i nch as i ndi cat ed i n t he m eet i ng not es) nom i nal pl at es t o t he 1.154 i nch nom i nal pl at es a t el ev at i on 23 f t 6 7/8 i nch ar e doubl e bev el f ul l penet r at i on wel ds. T he ex t er nal edge of t he 1.154 i nche s pl at es i s t aper ed t o 3 t o 12 m i ni m um as r equi r ed by A S M E S ect i on V I I I , S ubse ct i on U W-35, wh i l e t he i nt er nal edg e of t he 1.154 i nch p la te s a re f lu s h w ith th e 0.7 7 0 in c h p la te s. T h u s th e re a re n o le d g e s th a t c o u ld re ta in w a te r le a k a g e a n d re s u lt i n m o re s e v e re c o rro s io n th a n in a re a s in c lu d e d in t he i nspe ct i on pr ogr am. Al so, t hi s j oi nt i s l ocat ed bel ow t he equa t or i al cen t er of t he s pher e. T her ef or e, i n t he ev ent t hat wat er m ay r un down t he gap bet ween t he d ryw e ll s h e ll a n d th e c o n c re te w a ll it w o u ld n o t c o ll e c t o n th is jo in t.In 1 9 9 1 , O ys te r C re e k p e rf o rm e d ra n d o m in s p e c tio n s o f th e d ryw e ll s h e ll.U l t r ason i c t est i ng i nspe ct i ons wer e co nduc t ed at 19 l ocat i ons on ei t her t he 1.154 i n c h th i c k p l a te s o r o n th e 0.7 7 0 i n c h th i c k p l a te s. T h e U T m e a s u re m e n ts w e re t aken on a 6 i nch x 6 i nch gr i d (49 UT s) at eac h l ocat i on. T he UT m easu r em ent 4-46 r esul t s s how t hat t hi nni ng of t he pl at es a t t hese l ocat i ons i s l ess sev er e t han t he ar eas t hat ar e i ncl uded i n t he c or r osi on-m oni t or i ng pr ogr am. For t hi s r easo n, t he t r ansi t i on ar ea was not added t o t he c or r osi on-m oni t or i ng pr ogr am. Based on t he abov e, Am er G en c oncl udes t hat ar eas m oni t or ed unde r t he dr y wel l cor r osi on m oni t or i ng p r ogr am bou nd t he t r ansi t i on (f r om 1.154 i nche s t o 0.770 i nch t hi ck pl at es) ar ea of t he dr y wel l she l l. N ev er t hel ess , U T m easu r em ent s wi l l be t aken on t he 0.770 i nch t hi ck pl at e, j ust abov e t he wel d, pr i or t o ent er i ng t he per i od of e x te n d e d o p e ra tio n. T he m easu r em ent s wi l l be co ndu ct ed a t one l ocat i on u si ng t he 6 i nch x 6 i nch gr i d. A secon d se t of U T m easu r em ent s wi l l be t aken t wo r ef uel i ng out ages l at er at t he s am e l ocat i on. T he r esul t s of t he m easu r em ent s wi l l be ana l y z ed and ev al uat ed t o co nf i r m t hat t he r at e of cor r osi on i n t he t r ansi t i on i s bo unded b y t he ra te o f c o rro s io n o f th e m o n ito re d a re a s in th e u p p e r re g io n o f th e d ryw e ll. If cor r osi on i n t he t r ansi t i on ar ea i s f ound t o be gr eat er t han ar eas m oni t or ed i n t he upper r egi on of t he dr y wel l , U T i nspe ct i ons i n t he t r ansi t i on ar ea wi l l be per f or m ed o n th e s a m e f re q u e n c y a s th o s e p e rf o rm e d o n th e u p p e r re g io n o f th e d ryw e ll (e v e ry o th e r re fu e l i n g o u ta g e).S im il a rly, a re v ie w o f f a b ric a tio n a n d in s ta ll a tio n d e ta il s o f th e c o n ta in m e n t d ryw e ll shel l sho ws t hat t he wel d t hat con nect s t he 2.625" knu ck l e pl at es t o t he 0.640" cy l i nder pl at es a t el ev at i on 71 f t 6 i nch i s a d oubl e bev el f ul l penet r at i on w e ld. T h e e d g e s o f th e 2.6 2 5 in c h p la te s w e re f a b ric a te d w ith a 3 to 1 2 ta p e r to pr ov i de a s m oot h t r ansi t i on f r om t he t hi ck er t o t he t hi nner pl at e as r equi r ed by A S M E S e c tio n V III, S u b s e c tio n U E-3 5. T h u s th e re a re n o le d g e s th a t c o u ld re ta in wat er l eaka ge and r esul t i n m or e se v er e co r r osi on t han t he ar eas i ncl uded i n t he i n s p e c t i o n p r o g r a m.In 1 9 9 1 , O ys te r C re e k p e rf o rm e d ra n d o m in s p e c tio n s o f th e d ryw e ll s h e ll.U l t r ason i c t est i ng (U T) i nspe ct i ons wer e co nduc t ed at 18 l ocat i ons on t he 2.625 i nch t hi ck knu ck l e pl at e and a t f our (4) l ocat i ons on t he 0.640 i nch t hi ck cy l i nder pl at e. T he UT m easu r em ent s wer e t aken on a 6 i nch x 6 i nch gr i d (49 UT s) at each l ocat i on. T he UT m easu r em ent r esul t s s howed t hat t hi nni ng of t he pl at es a t t hese l ocat i ons was l ess sev er e t han t he ar eas t hat ar e i ncl uded i n t he c or r osi on m oni t or i ng pr ogr am. For t hi s r easo n t he k nuck l e ar ea was not added t o t he cor r osi on m oni t or i ng pr ogr am. Based on t he abov e, Am er G en c oncl udes t hat ar eas m oni t or ed unde r t he dr y wel l cor r osi on m oni t or i ng pr ogr am bound t he k n u c k l e a r e a o f t h e d r y w e l l s h e l l. H o w e ve r , U T m e a s u r e m e n t s w i l l b e t a k e n a b o ve t he 2.625 i nch knuc kl e pl at e i n t he 0.640 i nch t hi ck pl at e pr i or t o ent er i ng t he p e rio d o f e x te n d e d o p e ra tio n. T he s t af f v i ews r andom sam pl i ng of U T m easu r em ent as b ei ng v al uabl e i f t he l i kel i hood of cor r osi on i s al m ost equal at ev er y pl ace i n t he r egi on c onsi der ed f or U T m easu r em ent s. I f t he g e o m e try o f th e re g io n a n d w a te r f lo w in th e a ir g a p is s u c h th a t s u g g e s t its e lf th a t o n e a re a is m or e l i kel y t o hav e co r r osi on t han t he ot her , t hen t he s am pl i ng pl an has t o co nsi der t hose ar eas whi ch a r e m or e l i kel y t o hav e co r r osi on i n addi t i on t o t he r andom l y sel ect ed ar eas. I f t he wat er f l ow i n t he ai r gap i s hi gh, t he appl i cant's ar gum ent t hat t he wel d t r ansi t i on wi l l not al l ow wat er acc um ul at i on wi l l be ac cur at e. H owev er , i f t he wat er f l ow i s s l ow, t hi s m ay not hol d t r ue. D ur i ng t he f or t hcom i ng out age, t he appl i cant pl ans t o per f or m U T m easu r em ent s at one l ocat i on on e a c h o f th e tra n s iti o n a re a s.
4-47 T he s t af f bel i ev es t hat ex am i nat i on of 4 l ocat i ons i n eac h t r ansi t i on ar ea i s ne eded. T he l ocat i ons al ong t he t hi ck ness t r ansi t i on s houl d be c onsi st ent wi t h t he ar eas t hat hav e l ar ge wat er acc um ul at i on and cor r osi on i n t he s and bed r egi on. T hi s was i dent i f i ed as open i t em (O I) 4.7.2-1.1 i n t he SE R , dat ed August 18, 2006.T he appl i cant updat ed t he I W E P r ogr am com m i t m ent s i n i t s Decem ber 3, 2006, sub m i ss i on (pages 73 and 74, i t em s 10 and 11) wi t h f our sep ar at e se t s of U T t hi ck ness m easu r em ent s of t he dr y wel l she l l at t wo ar eas of t r ansi t i on bet ween s hel l pl at e t hi ck ness es u si ng a 6"x 6" gr i d (i.e., f our sep ar at e 49-poi nt U T set s at t he t r ansi t i on at el ev at i on 23' 6 7/8" and f our set s of U T s at el ev at i on 71'-6"). T he s peci f i c l ocat i ons sel ect ed wi l l be bas ed on p r ev i ous oper at i onal ex per i ence (i.e., bi ased t owar d ar eas t hat hav e ex per i ence d co r r osi on or ex posu r e t o wat er l eaka ge). T hese m easu r em ent s wi l l be at t he s am e l ocat i ons pr i or t o t he per i od of ex t ended ope r at i on a nd a t t he se cond r ef uel i ng o ut age af t er t he i ni t i al i nspe ct i on. I f cor r osi on i n t hese t r ansi t i on ar eas i s gr eat er t han i n ar eas m oni t or ed i n t he uppe r dr y wel l , U T i nspe ct i ons i n t he t r ansi t i on ar eas wi l l be on t he s am e f r equenc y as t hose i n t he uppe r dr y wel l (ev er y ot her r ef uel i ng out age). O f t hese f our l ocat i ons t her e wer e U T m easu r em ent s at t wo f or eac h t r ansi t i on ar ea dur i ng 2006 out age. T hese f i r st-t i m e r eadi ngs show t hat t he m ean and i ndi v i dual th ic k n e s s e s m e e t a c c e p ta n c e c rite ria w ith a d e q u a te m a rg in. T h e re w il l b e U T m e a s u re m e n ts in t he r em ai ni ng t wo l ocat i ons at eac h t r ansi t i on ar ea dur i ng t he nex t out age pr i or t o t he per i od of ex t ended o per at i on.T he appl i cant's ac t i ons t o i ncl ude i n t he pr ogr am U T m easu r em ent of she l l ar eas t hat m ay e xp e ri e n c e i n c re a s e d ra t e s o f c o rr o s i o n re s o l ve t h e s t a ff c o n c e rn. T h e b a s i s fo r t h e s t a ffs c o n c lu s io n is th a t th e U T m e a s u re m e n ts a s d e s c rib e d s h o u ld p ro v id e a n a d e q u a te d a ta b a s e to c o n f irm w h e th e r th e ra n d o m s a m p li n g p ro g ra m f o r U T m e a s u re m e n ts is re a s o n a b ly r epr esen t at i v e.T he s t af f , howev er , not ed an i ncon si st ency i n l i cens e r enewal C om m i t m ent 27, "AS M E S ect i on XI , Subsec t i on I W E," i t em s 10 and 11 , wher e i t st at es t hat t he UT m easu r em ent s wi l l be at one l ocat i on. I n di sc uss i ons on Decem ber 13, 2006, t he appl i cant i ndi cat ed t hat t hi s s t at em ent was an edi t or i al er r or. I n a s ubse quent l et t er dat ed Decem ber 15, 2006, Am er G en c or r ect ed t he er r or i n t he l i cens e r enewal com m i t m ent l i st. O pen I t em 4.7.1-1.1 i s c l osed.I n i t s l et t er dat ed Febr uar y 15, 2007, t he appl i cant r ev i sed a co m m i t m ent (C om m i t m ent N o. 27)by addi ng I t em 21, whi ch s t at es t hat t he per f or m ance of t he f ul l sc ope of dr y wel l san d bed r egi on i nspe ct i ons wi l l be c onduc t ed ev er y ot her r ef uel i ng out age. T he s t af f i dent i f i ed t hi s c om m i t m ent i t em as a l i cens e co ndi t i on.
O p e n Ite m 4.7.2-1.2: D ryw e ll S h e ll E m b e d d e d C o n c re te I n t he s and poc ket r egi on of t he dr y wel l she l l , t he m ost sus cept i bl e bay s ar e i ncor por at ed i n t he sam pl i ng. H owev er , t he s t af f bel i ev es t hat r eadi ngs shou l d be t aken v ul ner abl e l ocat i ons and th a t U T te c h n iq u e s a re re li a b le. T h e f irs t is s u e is a d d re s s e d b e lo w a n d th e s e c o n d is s u e is add r essed as pa r t of U T M easu r em ent I ssues.T he f i r st i t em i s t hat i t i s no t cl ear i f t he j unct i on bet ween t he 1.154- and t he 0.676-i nch pl at e at t he el ev at i on 6' 10.25" i s r epr esen t ed i n t he s am pl i ng. T hough t hi s po i nt i s be l ow t he bot t om of th e s a n d-p o c k e t a re a i n c o n ta c t w i th th e a l k a l i n e e n v i ro n m e n t o f c o n c re te , i n th e p a s t (b e fo re seal i ng of t he j unct i on bet ween t he s t eel and t he c oncr et e), t hi s ar ea woul d hav e been subj ect ed t o t he s am e t y pe of con t am i nat ed wat er as t he dr y wel l i n t he s and-pock et ar ea and i s c onsi der ed 4-48 as a sus pect ar ea f or cor r osi on. T he s t af f r eques t ed t hat t he appl i cant j ust i f y why t hi s ar ea shou l d not be i ncl uded i n t he s am pl i ng pl an.I n i t s r espo nse dat ed J une 20, 2006, t he appl i cant not ed t hat a r ev i ew of t he dr y wel l con st r uct i on and f abr i cat i on det ai l s s hows t hat t he dr y wel l sk i r t i s wel ded t o t he 1.154 i nch t hi ck pl at e bel ow t he s and bed f l oor. T hi s t hi ck pl at e i s wel ded t o t he 0.676 i nch pl at e at el ev at i on 6' 10.25". T he pur pose of t he s ki r t , whi ch i s al so e m bedded i n co ncr et e, was t o su ppor t t he dr y wel l dur i ng cons t r uct i on. T he pr esen ce o f t he s ki r t pr ev ent s m oi st ur e i nt r usi on i nt o t he 0.676 i nch pl at e.Q uot i ng t he pr ov i si ons of G ALL R epor t t he appl i cant not ed:
- C oncr et e m eet i ng t he s peci f i cat i ons of AC I 318 or 349 an d t he gui danc e of 201.2R was u s e d fo r th e c o n ta i n m e n t s h e l l o r l i n e r.
- T he c oncr et e i s m oni t or ed t o ens ur e t hat i t i s f r ee of cr ack s t hat pr ov i de a pa t h f or wat er s e e p a g e to th e s u rfa c e o f th e c o n ta i n m e n t s h e l l o r l i n e r.
- T h e m o is tu re b a rrie r, a t th e ju n c tio n w h e re th e s h e ll o r lin e r b e c o m e s e m b e d d e d , is s u b je c t to a g in g m a n a g e m e n t a c tiv iti e s in a c c o rd a n c e w ith A S M E C o d e S e c tio n X I, S ubse ct i on I W E r equ i r em ent s.
- W a te r p o n d i n g o n th e c o n ta i n m e n t c o n c re te flo o r a re n o t c o m m o n a n d w h e n d e te c te d a re c l e a n e d u p i n a ti m e l y m a n n e r.Addi t i onal l y , Am er G en c ont r act ed wi t h St r uct ur al I nt egr i t y Assoc i at es, I nc. (SI) t o pr ov i de an ass ess m ent of cor r osi on of t he em bedded dr y wel l she l l i n t he s and bed r egi on. T he appl i cant a s k e d S I to a d d re s s c o rro s io n o f th e d ryw e ll s h e ll p rio r to 1 9 9 2 , w h e n th e s h e ll w a s p o te n tia ll y ex pose d t o m oi st ur e r et ai ned by t he s and, and po st 1992 a f t er t he s and was r em ov ed and ot her m i t i gat i v e ac t i ons wer e t aken t o pr ev ent wat er i nt r usi on i nt o t he em bedded she l l. T he assessm ent r esul t s can b e sum m ar i z ed a s f ol l ow s:
- C o rro s io n o f th e E m b e d d e d D ryw e ll S h e ll p rio r to 1 9 9 2: T h e c o rro s io n o f th e d ryw e ll s h e ll i n t he s and bed r egi on was cau sed by t he m oi st ur e t r apped i n t he s and bed due t o wat er le a k a g e in to th e re g io n. T h e s o u r c e o f le a k a g e w a s d e te r m in e d to b e th e re a c to r c a v ity, whi ch i s f i l l ed wi t h dem i ner al i z ed wat er dur i ng r ef uel i ng out ages. T he wat er pas sed ov er t he Fi r ebar-D coa t i ng t hat was a ppl i ed t o t he dr y wel l she l l t o al l ow f or f or m at i on of t he re q u ire d s e is m ic g a p b e tw e e n th e d ryw e ll s h e ll a n d th e e n c irc li n g c o n c re te s h ie ld w a ll.T he Fi r ebar-D m at er i al i s a m agnes i um ox y chl or i de c om pound. T he dr y wel l was e r ect ed onsi t e an d exposed t o sal t ai r envi r onm ent dur i ng co nst r uct i on, wh i ch cou l d al so i nt r oduc e co nt am i nant s t o t he s and bed env i r onm ent. C hem i st r y t est r esul t s on wet san d cond uct ed i n 1986 i ndi cat ed t hat t he l each at e f r om t he m oi st san d had a pH of 8.46 and cont ai ned onl y 45 p pb ch l or i des a nd <1 7 pp b sul f at es.
- As not ed i n EP R I R epor t 100295 0, t hi s wat er i s no t aggr ess i v e t o co ncr et e si nce t he pH i s gr eat er t han 5.5, t he c hl or i des ar e l ess t han 500 ppm and s ul f at es a r e l ess t han150 0 ppm. T hi s m eans t hat t he wet t ed c oncr et e env i r onm ent wi l l pr ov i de a hi gh pH env i r onm ent t hat wi l l pr ot ect t he em bedded she l l f r om cor r osi on. Addi t i onal l y , t he cor r osi on r at es c al cul at ed f or t he c ar bon s t eel pl ugs r em ov ed f r om t he dr y wel l she l l i n t he s a n d b e d re g i o n w e re c o m p a ra b l e to c a rb o n s te e l e x p o s e d to ty p i c a l w a te rs o v e r a s im il a r te m p e ra tu re ra n g e. W h il e a n in c re a s e in th e s a li n ity a n d im p u rity o f th e w a te r w il l in c re a s e th e k in e tic s o f th e c o rro s io n re a c tio n b y i n c re a s in g th e e le c tro ly te c o n d u c tiv ity a n d c a n a lte r th e f o rm o f c o rro s io n e x p e rie n c e d b y s te e l (e.g., fr o m g e n e ra l c o rro s io n to 4-49 pi t t i ng c or r osi on), i m pur i t i es s uch as c hl or i de and sul f at e ar e not f undam ent al l y i nv ol v ed i n t he c or r osi on anod i c an d ca t hodi c r eact i ons. I n f act , i ncr easi ng t he s al i ni t y of t he wat er decr ease s t he di ss ol v ed ox y gen c ont ent of t he wat er and, t hus, r educ es t he conc ent r at i on of cat hodi c r eact ant pr esen t f or t he c or r osi on r eact i on.T he appl i cant st at ed t hat i t i s r easo nabl e t o as sum e t hat t he c or r osi on r at e of t he em bedded shel l i s si gni f i cant l y l ess t han t he sh el l i n con t act wi t h t he sa nd b ed f or t wo pr i m ar y r easo ns:
- The c ar bo n s t ee l i n t he embed de d r eg i on i s i n c on t ac t wi t h h i gh pH c on c r et e t ha t al l ow s t he c r eat i on of a pas si v e f i l m on t he s t eel sur f ace. T hat i s, t he pr esen ce o f abunda nt am ount s of cal ci um hy dr ox i de and r el at i v el y sm al l am ount s of al kal i el em ent s, suc h as sodi um and pot assi um , gi v es con cr et e a ver y hi gh a l kal i ni t y (e.g., pH of 12 t o 13). I n f act t her m ody nam i c c al cul at i ons r ev eal no c or r osi on of i r on (st eel) abov e pH 10 at r oom t em per at ur e.
- U n i fo rm c o rro s i o n w i l l te n d to o c c u r w h e n s o m e s u rfa c e re g i o n s b e c o m e a n o d i c fo r a shor t per i od, but t hei r l ocat i on and t hat of t he c at hodi c r egi ons cons t ant l y cha nge. For e x a m p le , g e n e ra l c o rro s io n/ru s tin g o f m il d s te e l w il l o c c u r w h e n th e re is a u n ifo rm s u p p ly of ox y gen av ai l abl e ac r oss t he s ur f ace of t he s t eel and t her e i s a u ni f or m di st r i but i on of def ect s i n t he ox i de f i l m as i s us ual l y t he c ase i n t he non-pr ot ect i v e f i l m s f or m ed on una l l oy ed st eel. I n t he a bsen ce of ar eas o f hi gh i nt er nal st r ess (e.g., col d-wo r ked r egi ons)or seg r egat ed z ones (e.g., non-uni f or m di st r i but i ons of sul f i de i ncl usi ons), a num ber of a n o d ic re g io n s w il l d e v e lo p a c ro s s th e s u rf a c e. S o m e a re a s w il l b e c o m e le s s a c tiv e w h il e new anod i c r egi ons beco m e av ai l abl e. T her ef or e, ov er al l at t ack t akes pl ace at a num ber of anodi c s i t es who se p osi t i ons m ay cha nge, l eadi ng t o gener al r ust i ng ac r oss t he sur f ace.I f t he s uppl y of ox y gen i s no t uni f or m acr oss a su r f ace, t hen any r egi ons t hat ar e depl et ed in o x yg e n w il l b e c o m e a n o d ic a s th e c a s e o f m o is t s a n d in c o n ta c t w ith th e d ryw e ll s te e l.T h e re m a in d e r o f th e d ryw e ll s u rf a c e in c lu d in g th e e m b e d d e d s te e l h a s o x yg e n a v a il a b le t o i t and t her ef or e ac t s as a l ar ge c at hodi c ar ea. W hen t he c at hodi c ar ea i s l ar ger , l ocal at t ack wi l l occ ur i n t he s m al l er anodi c r egi on. T hi s ph enom enon i s r ef er r ed t o as di f f er ent i al aer at i on.T h e re f o re , d u e to th e c re a tio n o f a d iff e re n tia l a e ra tio n c e ll , th e a d ja c e n t c a rb o n s te e l i n cont act wi t h t he m oi st san d bed a ct s as an ano de t hat sac r i f i ces i t sel f t o t he bene f i t of t he st eel i n t he em bedded r egi on. T hat i s, t he c or r osi on of t he s and c ushi on s t eel p re f e re n tia ll y c o rro d e s a s g a lv a n ic a ll y c o u p le d to th e e m b e d d e d s te e l.T h e a p p li c a n t, a ls o d is c u s s e d p o te n tia l fo r c o rro s io n o f th e e m b e d d e d d ryw e ll s h e ll a f te r 1 9 9 2. In re s p o n s e to R A I 4.7.2-1 (c) A m e rG e n d e s c rib e d s e v e ra l c o rre c tiv e a c tio n s ta k e n to m iti g a te cor r osi on of t he dr y wel l she l l. T hese m i t i gat i v e ac t i ons ar e des i gned t o m i ni m i z e wat er i nt r usi on i nt o t he s and bed r egi on, pr ov i de f or an ef f ect i v e dr ai nage of t he r egi on i n t he ev ent of wat er l eaka ge and m oni t or t he dr ai ns t o det ect l eaka ge. I f wat er l eaka ge i s ob ser v ed c om i ng f r om t he sand bed r egi on dr ai ns, num er ous i nv est i gat i v e and c or r ect i v e ac t i ons wi l l be t aken. I n addi t i on, a s il ic o n e s e a l i s a p p li e d a t th e ju n c tio n o f d ryw e ll s h e ll a n d th e s a n d b e d c o n c re te f lo o r to pr ev ent i nt r usi on of m oi st ur e i nt o t he em bedded dr y wel l she l l. T hese act i ons m i t i gat e su bseq uent l ong t er m si gni f i cant cor r osi on o f t he e m bed ded shel l f or t he f ol l ow i ng t wo r easo ns:
- T he gene r al l ack of t wo of t he f our nec ess ar y f undam ent al par am et er s ne ces sar y f or any f o rm o f c o rro s io n to o c c u r, a n e le c tro ly te , (i.e., m o is tu re) a n d th e c a th o d ic re a c ta n t (i.e.,
4-50 ox y gen), whi l e onl y t he l ack of one f undam ent al par am et er i s s uf f i ci ent t o pr ev ent cor r osi on. Seal i ng of f t he em bedded st eel wi l l pr ev ent any r ef r eshm ent of m oi st ur e i n t he em bedded r egi on and any r esi dual m oi st ur e wi l l not sup por t any sub sequ ent cor r osi on once al l t he di ss ol v ed ox y gen i s c onsu m ed i n t he c at hodi c c or r osi on r eact i on. T he c e s s a tio n o f th e c o rro s io n re a c tio n w il l o c c u r re g a rd le s s o f th e p re s e n c e o f c o n ta m in a n ts t hat m ay be d i ssol v ed i n t he w at er (e.g., chl or i de, sul f at e, et c.) si nce a l t hou gh t hese i m pur i t i es c an af f ect t he k i net i cs of t he c or r osi on r eact i on, t hey do not par t i ci pat e i n t he cat hodi c r educ t i on r eact i on. O nce t he c at hodi c r eact i on i s s t opped, cor r osi on i s s t opped.I nt er m i t t ent wet t i ng and aer at i on of t he em bedded st eel woul d pr oduc e onl y m i ni m al addi t i onal cor r osi on.
- T he pr esen ce o f con cr et e i n co nt act wi t h t he em bedded st eel wi l l m i t i gat e co r r osi on ev en if s u f f ic ie n t m o is tu re a n d o x yg e n a re a v a il a b le d u e to th e s p o n ta n e o u s f o rm a tio n o f a th in pr ot ect i v e ox i de pas si v e f i l m on t he em bedded st eel sur f ace i n t he hi ghl y al kal i ne s ol ut i on of t he c oncr et e. As l ong as t hi s f i l m i s no t di st ur bed, i t wi l l kee p t he s t eel pas si v e and pr ot ect ed f r om cor r osi on.I n su m m ar y , t he appl i cant not ed t hat Am er G en has ex t ensi v el y i nv est i gat ed dr y wel l cor r osi on, i ncl udi ng t he em bedded she l l. A r ev i ew of pl ant oper at i ng and i ndus t r y ex per i ence i ndi cat es t hat cor r osi on of em bedded st eel i n co ncr et e i s no t si gni f i cant bec ause i t i s pr ot ect ed by t he hi gh a lk a li n ity in c o n c re te. C o rro s io n c o u ld o n ly b e c o m e s ig n ific a n t if th e c o n c re te e n v iro n m e n t is aggr ess i v e. Al so, hi st or i cal dat a sh ows t hat t he env i r onm ent i n t he s and bed r egi on i s no t a g g re s s iv e , a n d th u s a n y w a te r in c o n ta c t w ith th e e m b e d d e d s h e ll is n o t a g g re s s iv e. T h e d a ta al so s hows t hat cor r osi on of t he dr y wel l she l l i n t he s and bed r egi on i s du e t o gal v ani c c or r osi on and i m pur i t i es s uch as c hl or i des and s ul f at es a r e not f undam ent al l y i nv ol v ed i n t he c or r osi on a n o d ic a n d c a th o d ic re a c tio n s. T h u s , o n ly li m ite d c o rro s io n w o u ld b e a n tic ip a te d f o r th e d ryw e ll e m b e d d e d s h e ll.Am er G en has al so c om m i t t ed t o a c om pr ehens i v e dr y wel l cor r osi on-m oni t or i ng pr ogr am f or t he per i od of ex t ended o per at i on. T he pr ogr am i ncl udes m i t i gat i v e m easu r es t o pr ev ent wat er i n t r u s i o n i n t o t h e s a n d b e d r e g i o n. T h e s a n d b e d r e g i o n c o n c r e t e fl o o r i s s e a l e d w i t h e p o xy coat i ng. T he j unct i on bet ween t he s and bed r egi on c oncr et e f l oor and t he dr y wel l she l l was seal ed i n 1992 t o pr ev ent m oi st ur e f r om i m pact i ng t he em bedded she l l. T hus, addi t i onal si gni f i cant cor r osi on of t he em bedded she l l i s no t ex pect ed bec ause of l ack of m oi st ur e and depl et ed ox y gen. Am er G en wi l l al so t ake spec i f i c ac t i ons i f wat er l eaka ge i s de t ect ed i n t he s and bed r egi on d r ai ns.For al l of t he abov e r easo ns, t he appl i cant st at ed t hat t he c or r osi on r at e f or t he em bedded dr y wel l she l l i s l ess t han t he c or r osi on r at e of t he s and bed r egi on of t he dr y wel l she l l. Al so, d ire c t m o n ito rin g o f th e d ryw e ll s h e ll in th e s a n d b e d re g io n a d e q u a te ly b o u n d s a n y c o rro s io n in th e d ryw e ll e m b e d d e d s h e ll.A m e rG e n c o n c lu d e d th a t c o rro s io n m o n ito rin g o f th e s a n d b e d re g io n o f th e d ryw e ll s h e ll is boundi ng wi t h r espe ct t o co r r osi on t hat m ay hav e oc cur r ed on t he dr y wel l em bedded she l l pr i or t o 1992. Af t er 1992, cor r osi on of t he em bedded she l l has not been s i gni f i cant bec ause of t he m i t i gat i v e m easu r es i m pl em ent ed and t he r obus t dr y wel l cor r osi on AM P and t he appl i cant conc l uded t hat t hi s t r end of no s i gni f i cant cor r osi on wi l l con t i nue dur i ng t he per i od of ex t ended oper at i on.
4-51 T he s t af f under st ands Am er G en's t echn i cal r easo ns t o su ppor t t he appl i cant's v i ew t hat t he i nacc ess i bl e por t i on of t he dr y wel l she l l (i.e. em bedded bet ween t he c oncr et e f l oor i nsi de, and conc r et e out si de) i s no t l i kel y t o be s ubj ect t o t he s am e t y pe of sev er e co r r osi on as ex per i ence d i n t he s and bed ar ea. H owev er , t he ex per i ence of gener al cor r osi on i n t he l i ner pl at es e m bedded i n co ncr et e of a num ber of PW R and BW R con t ai nm ent s s ugges t s t hat cer t ai n i r r egul ar i t i es dur i ng t he c onst r uct i on (i.e. f or ei gn obj ect s or v oi ds i n t he c oncr et e) cou l d t r i gger cor r osi on t hat i s no t ar r est ed l at er by t he c oncr et e env i r onm ent. T hi s i s pa r t i cul ar l y si gni f i cant f or t he pl at es pot ent i al l y sub j ect t o wat er see page. T he appl i cant's po si t i on t hat t he uni f or m l y r educ ed th i c k n e s s u s e d i n th e G E a n a l y s i s c o m p e n s a te s fo r a n y c o rro s i o n th a t m a y h a v e o c c u rre d b e fo re t he ar ea was sea l ed i n 1992 has som e v al i di t y. Becaus e t he s t af f was s t i l l ev al uat i ng, t hi s i t em was i dent i f i ed as O I 4.7.2-1.2 i n t he SE R , dat ed August 18, 2006.D u rin g th e O c to b e r 2 0 0 6 re f u e li n g o u ta g e , th e a p p li c a n t in s p e c te d th e e m b e d d e d d ryw e ll s h e ll in t he t r ench es i n bay s #5 and #1 7 af t er r em ov i ng t he f i l l er m at er i al i n t he t r ench es a nd obs er v ed appr ox i m at el y 5 i nche s of st andi ng wat er i n t he t r ench l ocat ed i n bay #5, and t he t r ench i n bay#17 was dam p. I nv est i gat i ons conc l uded t hat t he l i kel y wat er sou r ces wer e a det er i or at ed dr ai npi pe c onnec t i on and a v oi d i n t he bot t om of t he Sub-Pi l e R oom dr ai nage t r ough or c o n d e n s a tio n w ith in th e d ryw e ll th a t e ith e r f e ll o r w a s h e d d o w n th e in s id e o f th e d ryw e ll s h e ll to th e c o n c re te f lo o r. W a te r s a m p le s ta k e n f ro m th e tre n c h in b a y #5 w e re te s te d a n d d e te rm in e d to be non-aggr ess i v e i n pH (8.4 - 10.21), chl or i des (13.6 - 14.6 ppm), and s ul f at es (228 - 2 30 p p m). T he appl i cant ent er ed t he c ondi t i on i nt o t he c or r ect i v e ac t i on pr oces s. Sev er al cor r ect i v e ac t i ons i ncl uded r epai r of t he t r ough c oncr et e i n t he ar ea unde r t he r eact or v ess el t o pr ev ent wat er f r om m i gr at i ng t hr oug h t he co ncr et e an d r each i ng t he d r y we l l shel l and caul ki ng o f t he i nt er f ace bet ween t he dr y wel l she l l and t he dr y wel l con cr et e f l oor/cur b i ncl udi ng t he t r ench ar eas. T he tre n c h b a y i n b a y #5 a ls o w a s e x c a v a te d to u n c o v e r a n a d d iti o n a l 6 in c h e s o f th e in te rn a l d ryw e ll shel l sur f ace f or i nspe ct i on a nd U T t hi ckness m easu r em ent. A t ot al of 584 U T t hi ckness m easu r em ent s wer e t aken usi ng a 6"x 6" t em pl at e wi t hi n t he t wo t r ench es. For t y-t wo addi t i onal U T m easu r em ent s wer e t aken i n t he newl y ex pose d ar ea i n bay #5.V is u a l e x a m in a tio n o f th e d ryw e ll s h e ll w ith in th e tw o tre n c h e s d e te c te d m in o r s u rf a c e ru s t w ith no r ecor dabl e co r r osi on on t he i nner sur f ace of t he s hel l. T he UT m easu r em ent s i ndi cat ed t hat t he d r y we l l shel l i n t he t r ench ar eas h ad e x per i ence d a 0.038" r edu ct i on i n aver age t hi ckness si nce 1986. Am er gen c oncl uded t hat t he wal l t hi nni ng was a r esul t of cor r osi on on t he ex t er i or sur f ace of t he dr y wel l she l l i n t he s and bed r egi on bet ween 198 6 and 1 992 when t he s and was s til l i n p la c e a n d th e c o rro s io n w a s k n o w n. An engi neer i ng ev al uat i on t o det er m i ne t he i m pact of t he as-f ound wat er on t he c ont i nued i nt egr i t y of t he dr y wel l con cl uded t hat t he m easu r ed wat er che m i st r y v al ues and t he l ack of any i n d i c a t i o n s o f r e b a r d e g r a d a t i o n o r c o n c r e t e s u r fac e s p a l l i n g s u g g e s t t h a t t h e p r o t e c t i ve p a s s i ve f i l m est abl i shed dur i ng co ncr et e i nst al l at i on a t t he e m bed ded st eel/concr et e i nt er f ace i s st i l l i nt act and t hat si gni f i cant cor r osi on of t he dr y wel l she l l i s no t ex pect ed as l ong as t hi s be ni gn env i r onm ent i s m ai nt ai ned. Mor e sp eci f i cal l y , t hi s en gi neer i ng ev al uat i on i ndi cat es t hat no si gni f i cant cor r osi on of t he i nner sur f ace of t he em bedded dr y wel l she l l i s an t i ci pat ed f or t he f ol l ow i ng r easo ns:
- T he wat er i n co nt act wi t h t he dr y wel l she l l has been i n co nt act wi t h t he adj acen t con cr et e, whi ch i s al kal i ne, i ncr ease s t he pH of t he wat er , and i nhi bi t s c or r osi on. T hi s hi gh-pH wat er con t ai ns l ev el s of i m pur i t i es s i gni f i cant l y bel ow t he EP R I em bedded st eel gui del i nes a ct i on l evel r ecom m end at i ons.
4-52
- A n y n e w w a te r (e.g., r eact or coo l ant) ent er i ng t he c oncr et e-t o-shel l i nt er f ace (now m in im ize d b y re p a irs) a ls o in c re a s e s p H b y i ts m ig ra tio n th ro u g h a n d c o n ta c t w ith c o n c re te , c re a tin g a n o n-a g g re s s iv e , a lk a li n e e n v iro n m e n t.
- M in im a l c o rro s io n o f th e w e tte d in n e r d ryw e ll s te e l s u rf a c e in c o n ta c t w ith c o n c re te is ex pect ed onl y dur i ng out ages bec ause t he dr y wel l i s i ner t ed wi t h ni t r ogen du r i ng oper at i ons. Ev en dur i ng out ages , she l l cor r osi on l oss es a r e ex pect ed t o be i nsi gni f i cant as t he ex posu r e t i m e t o ox y gen i s v er y l i m i t ed and t he wat er pH i s ex pect ed t o be re l a ti v e l y h i g h. A l s o re p a i rs/m o d i fic a ti o n s d u ri n g th e 2 0 0 6 o u ta g e w i l l fu rth e r m i n i m i ze ex posu r e of t he dr y wel l she l l t o ox y gen.A f te r th e U T th ic k n e s s m e a s u re m e n t d u rin g th e 2 0 0 6 o u ta g e o f th e n e w ly-e x p o s e d s h e ll a re a in b a y #5 , w h ic h h a d n o t b e e n e x a m in e d s in c e in iti a l c o n s tru c tio n , a re d u c tio n o f a v e ra g e s h e ll t hi ck ness of 0.041" was o bser v ed. T he appl i cant m ai nt ai ns t hat , al t hough n o co nt i nui ng cor r osi on i s ex pect ed, t her e i s s uf f i ci ent m ar gi n f or bot h t he 1.154" t hi ck pl at e and t he 0.676"t hi ck pl at e ev en as sum i ng t he s am e r educ t i on unt i l t he end of t he per i od of ex t ended o per at i on.T h e a p p li c a n t a ls o h a s e n h a n c e d th e A M P to re q u ire p e rio d ic in s p e c tio n o f th e d ryw e ll s h e ll subj ect t o con cr et e (wi t h w at er) envi r onm ent s i n t he i nt er nal em bed ded shel l ar ea. A f t er each i n s p e c t i o n , UT t h i c k n e s s me a s u r e me n t s w i l l b e e v a l u a t e d a n d c o mp a r e d t o p r e v i o u s UT t hi ck ness m easu r em ent s. I f r esul t s ar e uns at i sf act or y , addi t i onal cor r ect i v e ac t i ons, as nece ss ar y , wi l l m ai nt ai n dr y wel l she l l i nt egr i t y t hr oughou t t he per i od of ex t ended o per at i on.T o in v e s tig a te th e f e a s ib il ity o f s ta te-o f-th e-a rt n o n-d e s tru c tiv e e x a m in a tio n te c h n iq u e s to d e te rm in e th e c o n d iti o n o f th e e m b e d d e d re g io n , th e a p p li c a n t c o n ta c te d E P R I a n d o th e r u til ity owner s t hat use t hese t echn i ques. Af t er di sc uss i ons and f i ndi ngs, t he appl i cant under st ood t hat a "gui ded wav e" t echn ol ogy m ay be abl e t o pr ov i de s om e qual i t at i v e i nf or m at i on on whe t her t he embed de d s he l l ha s un de r go ne c or r os i on; ho we v er , ne i t he r t hi s no r an y ot he r k no wn non-dest r uct i v e m et hods cou l d det er m i ne t he t hi ck ness of t he em bedded dr y wel l she l l or t he spec i f i c ex t ent of cor r osi on.Based on r ev i ew of t he appl i cant's ev al uat i on of t he c ondi t i on of t he i nacc ess i bl e por t i on of d ryw e ll s h e ll e m b e d d e d in c o n c re te , th e a p p li c a n t's a c tio n s to d a te to m in im ize e n try o f w a te r in t h e c o n c r e t e-t o-s h e l l i n t e r f a c e , a n d t h e e n h a n c e d i n s p e c t i o n p r o g r a m i n c l u d i n g a d e t a i l e d UT m easu r em ent pl an of t he em bedded she l l ar ea c om m i t t ed by t he appl i cant , t he s t af f con cl udes wi t h r easo nabl e as sur ance t hat t he env i r onm ent i n t he r egi on i s s uf f i ci ent l y non-aggr ess i v e f or no s i gni f i cant pr ogr ess i v e co r r osi on. T her ef or e, t he s t af f con cer n i s r esol v ed and O pen I t em 4.7.2-1.2 i s c l osed.I n i t s l et t er dat ed Febr uar y 15, 2007, t he appl i cant cha nge a c om m i t m ent (C om m i t m ent N o. 27)by addi ng I t em 20, whi ch s t at es Am er G en i s c om m i t t ed t o per f or m v i sual and UT i nspe ct i ons of t he dr y wel l she l l i n t he i nspe ct i on t r ench es i n dr y wel l bay s #5 and #1 7. Am er G en wi l l m oni t or t he tw o tre n c h e s f o r th e p re s e n c e o f w a te r d u rin g e a c h re f u e li n g o u ta g e. T h e s ta f f id e n tifie d th is com m i t m ent i t em as a l i cens e co ndi t i on.
U l t r ason i c Test i ng Measur em ent I ss ues I n t he s and poc ket r egi on of t he dr y wel l she l l , t he m ost sus cept i bl e bay s ar e i ncor por at ed i n t he sam pl i ng. H owev er , t he s t af f bel i ev es t hat r eadi ngs shou l d be t aken at v ul ner abl e l ocat i ons and 4-53 t hat U T t echn i ques ar e r el i abl e. T he f i r st i ss ue i s ad dr ess ed as par t of O pen I t em 4.7.2-1.2 and t he s ec on d i s s ue i s ad dr es s ed be l ow.T he s econ d i t em i s t hat a r ev i ew of U T dat a i ndi cat es t hat t he UT m easu r em ent s t aken f r om i nsi de t he dr y wel l af t er 1992 s how a gen er al i ncr ease i n t he m et al t hi ck ness. I n so m e ca ses , t he a v e r a g e i n c r e a s e i s a s mu c h a s 4 0 mi l s i n a 2-y e a r t i me f r a me. I n g e n e r a l , i t a p p e a r s t h a t t h e UT m e a s u re m e n ts ta k e n a f te r 1 9 9 2 re q u ire p ro p e r c a li b ra tio n , c o n s id e rin g th e c o a tin g s o n b o th si des of t he dr y wel l she l l. T he s t af f r eques t ed t hat t he appl i cant addr ess t hi s i ss ue dur i ng a publ i c m eet i ng hel d Ju ne 1, 2006.I n i t s r espo nse dat ed J une 20, 2006, t he appl i cant pr ov i ded t he f ol l owi ng di sc uss i on of sens i t i v i t i es i nv ol v ed wi t h t he UT m easu r em ent pr oces s an d how t hey wi l l be m i ni m i z ed i n t he f ut ur e:U T In s tru m e n ta ti o n U n c e rta i n ti e s. T h e U T i n s tru m e n ta ti o n , w h i c h i n c l u d e s th e tra n s d u c e r, cabl e an d ul t r ason i c uni t , wi l l be ca l i br at ed t o w i t hi n ap pr oxi m at el y +/- 0.010 i nche s.Ex el on Pr oced ur e (ER-AA-335-004) st ep 4.1.3 r equi r es t hat he UT i nst r um ent s m ust be chec ked wi t hi n 2% of t he c al i br at i on s t andar d (bl ock) pr i or t o us e. For t he s and bed re g io n , w h ic h is n o m in a ll y 1" th ic k , a 1-in c h th ic k c a li b ra tio n s ta n d a rd b lo c k is u s e d. T h is r e s u l t s i n c h e c k i n g t h e UT i n s t r u me n t t o w i t h i n 0.0 2 0" i n c h e s o r +/- 0.0 1 0". UT i nst r um ent at i on a ccur acy i s v er i f i ed u nde r cont r ol l ed co ndi t i ons w her e U T t hi ckness re a d in g s a re p e rf o rm e d o n c a li b ra tio n b lo c k s. T h e c a li b ra tio n b lo c k s h a v e b e e n p re c is e ly m achi ned t o pr escr i bed t hi cknesse s, wh i ch ar e t hen v er i f i ed b y m i cr om et er r ead i ngs.Act ual D r y wel l Sur f ace R oughne ss and UT Pr obe Loc at i on Repeat abi l i t y. D ue t o t he cor r osi on, t he out si de s ur f ace of t he Dr y wel l Vessel i s no t sm oot h and u ni f or m. T he sur f ace cond i t i on i s i ndi cat i v e of gener al cor r osi on, whi ch i s r ough wi t h hi gh and l ow poi nt s s pace d v er y cl osel y t oget her. T hi s pr of i l e was v er i f i ed when t he s and was r em ov ed i n 1992. T he UT I nst r um ent at i on pr obes ar e 7/16" i n di am et er and ar e dual el em ent tra n s d u c e rs (i.e. h a lf tra n s m its s o u n d a n d th e o th e r h a lf re c e iv e s). T h e p ro b e s e m it a f o c u s e d b e a m th a t m e a s u re s a n a re a s ig n ific a n tly s m a ll e r th a n 7/1 6" d ia m e te r a n d w il l re c o rd th e th in n e s t re a d in g w ith in th a t a re a. Because t he s ur f ace r oughne ss of t he dr y wel l wi t hi n t hi s 7/16" di am et er can v ar y , t he pr obe m ust be p l aced at pr eci sel y t he sa m e l ocat i on t o pr eci sel y r epe at a t hi ckness r eadi ng. A sl i ght shi f t of t he pr obe wi l l r esul t i n a r eadi ng whi ch i s c or r ect , but di f f er ent f ro m a p re v io u s re a d in g. T he v ar i abi l i t y ass oci at ed wi t h t hi s f act or i s r educ ed by t he us e of t he s t ai nl ess st eel t em pl at e. T he t em pl at e ha s bee n m anu f act ur ed w i t h ho l es i n a 7 by 7 pa t t er n on 1 i nch cent er s. Each of t he 49 h ol es h as b een m achi ned wi t h a di am et er so t hat t he UT pr obe f i t s wi t hi n ea ch ho l e snu gl y. T he t em pl at es ar e m achi ned wi t h 1/16" wi de sl i t s on e ach edge of t he t em pl at e at 0, 90, 180, and 27 0 degr ees. D ur i ng i nspe ct i ons t he s l i t s i n t he t em pl at e ar e l i ned up wi t h per m anent m ar ks t hat wer e pl aced on t he dr y wel l she l l when t he l ocat i on was or i gi nal l y i nspe ct ed. T he UT r eadi ngs ar e t hen t aken by pl aci ng t he pr obe i nsi de eac h hol e i n t he t em pl at e.I nspe ct i on pr oced ur es r equi r e t hat N D E per sonn el per f or m i ng t he i nspe ct i on pl ace t he t em pl at e pr eci sel y on t he p er m ane nt m ar ki ngs.
4-54Act ual D r y wel l Sur f ace R oughne ss and UT Pr obe Rot at i on. T he UT pr obe s ends t he si gnal f r om one s i de of t he pr obe and r ecei v es t he s i gnal on t he ot her si de. T he pr obe m u s t b e o rie n te d in th e s a m e p la n e in o rd e r to m e a s u re e x a c tly th e s a m e p o in t. T e s t d a ta t aken on a m ock up wi t h si m i l ar r oughne ss sho wed t hat a v ar i ance up t o 0.016 i nch was not ed when r ot at i ng t he pr obe 360 degr ees ov er t he s am e sp ot. T her ef or e, a sl i ght r ot at i on of t he pr obe wi l l r esul t i n a r eadi ng, whi ch i s c or r ect , but di f f er ent f r om a pr ev i ous r eadi ng.I nspe ct i on pr oced ur es r equi r e t hat N D E per sonn el per f or m i ng t he i nspe ct i on pl ace t he pr obe i n t he s am e or i ent at i on.T e m p e ra tu re E f f e c ts. S ig n ific a n t te m p e ra tu re d iff e re n c e s b e tw e e n in s p e c tio n s m a y re s u lt i n a s hi f t i n t he m at er i al t hi ck ness. T her ef or e, t he i nspe ct i on s peci f i cat i on wi l l r equi r e t hat N D E per sonn el per f or m i ng t he i nspe ct i on r ecor d t he s ur f ace t em per at ur e of t he ar ea t hat i s i nspe ct ed.B at t er i es. I nspe ct i on sp eci f i cat i ons r equ i r e t he i nst al l at i on o f new bat t er i es pr i or t o ea ch ser i es of i nspe ct i ons.ND E Te c h n i c i a n. I n s p e c t i o n s p e c i f i c a t i o n s r e q u i r e t h a t p e r s o n n e l c o n d u c t i n g UT ex am i nat i ons be qual i f i ed i n ac cor danc e wi t h Ex el on Pr oced ur e ER-AA-335-004.C al i br at i on Bl ock. Ex el on Pr oced ur e ER-AA-335-004 r equi r es t hat cal i br at i on bl ock s us ed dur i ng t he i nspe ct i on be i nspe ct ed t o v er i f y t hat t he ul t r ason i c r espo nse equal s t he p h ys ic a l m e a s u re m e n t.In te rn a l S u rf a c e C le a n li n e s s. T h e in s p e c tio n a re a s a re c o v e re d w ith a q u a li f ie d g re a s e to pr ot ect t he e x am i nat i on su r f ace f r om r ust i ng b et we en i nspe ct i on p er i ods. T he g r ease m u s t b e re m o v e d p rio r to th e in s p e c tio n a n d re a p p li e d a f te r th e in s p e c tio n. T e s ts per f or m ed i n A pr i l and M ay of 200 6 sho w t hat t he p r esen ce of t he g r ease wi l l i ncr ease th e re a d in g s a s m u c h a s 1 2 m il s. In 1 9 9 6 , th e g o v e rn in g s p e c ific a tio n d id n o t c le a rly s p e c ify th e re q u ire m e n t to re m o v e th e g re a s e p rio r to th e in s p e c tio n. T h e re f o re it i s poss i bl e t hat t he r equi r em ent t o r em ov e t he gr ease was n ot com m uni cat ed t o t he cont r act or , and t hat t he c ont r act or who per f or m ed t he 1996 i nspe ct i on m ay hav e not r em ov ed t he gr ease.T he i nspe ct i on pr oced ur es wi l l cl ear l y r equi r e t hat per sonn el con duct i ng UT ex am i nat i ons r em ov e t he gr ease pr i or t o per f or m i ng t he ex am i nat i on.U T U ni t Set t i ngs. I t i s po ss i bl e t hat t he ul t r ason i c un i t can be s et i n a " hi gh gai n" set t i ng wh i ch m ay bi as t he m achi ne i nt o i ncl udi ng t he e x t er nal coat i ng a s par t of t he t hi ckness.F u tu re in s p e c tio n s w il l u s e m o d e rn "s ta te o f th e a rt" U T u n its th a t d o n o t h a v e g a inset t i ngs.I dent i f i cat i on of t he Phy si cal I nspe ct i on Loc at i on. T her e i s a p ot ent i al t hat i nspe ct i on l ocat i ons m ay be m i sl abel ed on t he dat a sh eet s. T he i nspe ct i on pr oced ur es u ni quel y and cl ear l y i dent i f y eac h i nspe ct i on l ocat i on and pr ov i de t he s peci f i c i nst r uct i on as t o t he ar ea's l ocat i on.
4-55D at a Anal y si s. T he abov e pot ent i al v ar i abl es wi l l be c onsi der ed i n t he anal y si s of t he dat a. T he anal y si s no t onl y det er m i nes a m ean f or eac h gr i d or sub-gr i d, but al so t he v a ri a n c e o f th e m e a n s. T h e s e v a ri a n c e s w i l l b e c o m p a re d to p a s t i n s p e c ti o n s to e n s u re cons i st ency. T he m ean and t he v ar i ance ar e co m par ed t o t he ac cept ance cr i t er i a.I n addi t i on, t he m ean UT t hi ck ness v al ues f or a cu r r ent i nspe ct i on wi l l be c om put ed and com par ed t o t he pr ev i ous i nspe ct i on pr i or t o r est ar t i ng f r om an out age. I f dat a anom al i es s i mi l a r t o 1 9 9 6 a r e i d e n t i f i e d c o r r e c t i v e a c t i o n s w i l l b e t a k e n , i n c l u d i n g n e w UT m easu r em ent s, as ne cessar y , t o en sur e accu r acy of m easu r em ent s.B a s e d o n th e a p p li c a n t's d is c u s s io n o f th e v a ria b le s in v o lv e d in th e U T re s u lts , th e s ta f f f in d s it r easo nabl e t o co ncl ude t hat t he anom al ous r eadi ngs of 1994 a nd 1996 cou l d be at t r i but ed t o one o r m o re o f th e f a c to rs e n u m e ra te d in th e d is c u s s io n. T h e s ta f f w a s c o n c e rn e d a b o u t s ys te m a tic cor r ect i ons t o t he UT m easu r em ent s an d co ul d not det er m i ne t he bas i s f or t he appl i cant's us e of th e a n o m a l o u s re a d i n g s n o r s y s te m a ti c c o rre c ti o n s. T h e a p p l i c a n t c o u l d n o t i s o l a te th e fa c to rs t hat con t r i but ed t o t hese anom al ous r esul t s; t her ef or e, i t pl ans t o ut i l i z e t he l ess ons l ear ned f r om t he ex per i ence f or t he f ut ur e U T ex am i nat i ons. O n t he bas i s of t he appl i cant's wr i t t en r espo nse, th e s ta f f d e te rm in e d th a t its c o n c e rn s h a v e b e e n re s o lv e d.
4.7.2.2.2 M i ni m um D r y we l l T hi ckness I n R AI 4.7.2-1 dat ed Mar ch 1 0, 2006, t he s t af f r eques t ed t hat t he appl i cant pr ov i de a s um m ar y of th e f a c to rs c o n s id e re d in e s ta b li s h in g th e m in im u m re q u ire d d ryw e ll th ic k n e s s. In its re s p o n s e d a te d A p ril 7 , 2 0 0 6 , th e a p p li c a n t e x p la in e d th a t th e f a c to rs c o n s id e re d in e s ta b l i s h i n g th e m i n i m u m re q u i re d d ry w e l l th i c k n e s s a t va ri o u s e l e v a ti o n s o f th e d ry w e l l a re desc r i bed i n det ai l i n engi neer i ng anal y ses doc um ent ed i n t wo G E r epor t s, I ndex N os. 9-1, 9-2, and 9-3, 9-4. R epor t I ndex N o. 9-1, 9-2 was gener at ed f or t he dr y wel l con di t i on wi t h sa nd i n t he s a n d b e d re g io n a n d R e p o rt In d e x N o. 9-3 , 9-4 a d d re s s e d th e d ryw e ll c o n d iti o n w ith o u t s a n d in t he s and bed r egi on. T he t wo r epor t s wer e t r ansm i t t ed t o t he s t af f i n D ecem ber 1990 a nd 1991 , r espe ct i v el y. R epor t I ndex N o. 9-3, 9-4 was r ev i sed l at er t o co r r ect er r or s i dent i f i ed dur i ng an i n te rn a l a u d i t a n d w a s re s u b m i tt e d to th e s ta ff i n J a n u a ry 1 9 9 2. T h e a n a l y s i s d e s c ri b e d i n R e p o rt In d e x N o. 9-3 , 9-4 (i.e., w ith o u t s a n d) is th e c u rre n t a p p li c a b le a n a ly s is f o r th e d ryw e ll.I n i t s r espo nse t he appl i cant al so n ot ed t hat i t bas ed t he anal y si s on t he or i gi nal cod e of r ecor d, AS M E C ode, Sect i on VI l l , and Code C ases 1270N-5, 1271-N , and 12 72N-5. T he AS M E C ode and i t s Code C ases do not pr ov i de s peci f i c gu i danc e i n t wo ar eas. T he f i r st r el at es t o t he s i z e of a r egi on of i ncr ease d m em br ane s t r ess due t o t hi ck ness r educ t i ons f r om l ocal or gener al c o rro s io n e f f e c ts , a n d th e s e c o n d p e rta in s to th e a ll o w a b le s tre s s e s f o r S e rv ic e L e v e l C o r p o s t-a c c id e n t c o n d iti o n s. In th e f irs t c a s e , g u id a n c e w a s s o u g h t fr o m A S M E C o d e S e c tio n III, N E-321 3.10. Fo r S er v i ce Le v el C or post-acci den t cond i t i ons, t he S R P-LR wa s used as gu i dan ce to d e v e lo p th e a ll o w a b le s tre s s e s. A d d iti o n a ll y, th e a p p li c a n t s u m m a rize d th e a n a ly s is e f f o rts in t he f ol l ow i ng p ar agr aph s:T he anal y si s i s ba sed on a 36-degr ee s ect i on m odel t hat t akes adv ant age of sy m m et r y of t he dr y wel l wi t h 10 v ent s. T he m odel i ncl udes t he dr y wel l she l l f r om t he bas e of t he s and bed r egi on t o t he t op of el l i pt i cal head a nd t he v ent and v ent header. T he t or us i s no t i ncl uded i n t hi s m odel bec ause t he v ent bel l ows pr ov i de a v er y f l ex i bl e co nnec t i on, whi ch d oes not al l ow si gni f i cant st r uct ur al i nt er act i on bet ween t he dr y wel l and t he t or us. T he anal y si s c onsi der ed dr y wel l geom et r y and m at er i al s, t hi ckness r edu ct i on f r om cor r osi on, t est l oad s, nor m al ope r at i ng l oad s, 4-56 desi gn bas i s ac ci dent l oads , sei sm i c l oads , r ef uel i ng l oads , and de si gn bas i s l oad com bi nat i ons. Pr ess ur e and t em per at ur e wer e i n ac cor danc e wi t h appr ov ed T echn i cal Speci f i cat i on Am endm ent N o. 165, whi ch e st abl i shed a r ev i sed desi gn base s ac ci dent pr ess ur e of 44 ps i g and a cc i dent t em per at ur e of 292 E F. T he r esul t s of t he anal y si s s how t hat t he m i ni m um r equi r ed AS M E C ode t hi ck ness of t he dr y wel l she l l abov e t he s and bed r egi on i s c ont r ol l ed by m em br ane s t r ess es and t he m i ni m um dr y wel l she l l t hi ck ness i n t he s and bed r egi on i s c ont r ol l ed by buck l i ng. T he m i ni m um r equi r ed AS M E C ode t hi ck ness es a bov e t he s and bed r egi on ar e sh own i n T abl e 1 (at t ache d t o t he r espo nse). For t he s and bed r egi on, t he anal y si s c onse r v at i v el y ass um ed t hat t he s hel l t hi ck ness i n t he ent i r e sa nd b e d re g io n h a s b e e n re d u c e d u n ifo rm ly to a th ic k n e s s o f 0.7 3 6 in c h e s. T h is t hi ck ness sat i sf i es ASM E C ode r equi r em ent s an d i s c onsi der ed t he m i ni m um r equ i r ed t hi ckness.A s d e s c ri b e d a b o v e , t h e b u c k l i n g a n a l y s i s w a s p e rfo rm e d , a s s u m i n g a u n i fo rm g e n e r a l t h i c k n e s s o f t h e s a n d b e d r e g i o n o f 0.7 3 6 i n c h e s. Ho w e v e r , t h e UT m e a s u re m e n ts id e n tifie d is o la te d , lo c a li ze d a re a s w h e re th e d ryw e ll s h e ll t hi ck ness i s l ess t han 0.736 i nche s. Accept ance f or t hese ar eas was ba sed on engi neer i ng c al cul at i on C-1 302-1 87-5320-024. T he c al cul at i on us es a "Loca l W al l Accept ance C r i t er i a." T hi s c r i t er i on c an be a ppl i ed t o sm al l ar eas (l ess t han 12" by 12"), whi ch a r e l ess t han 0.736" t hi ck so l ong as t he s m al l 12" by 12" ar ea i s at l east 0.536" t hi ck. H owev er , t he c al cul at i on does not pr ov i de addi t i onal cr i t er i a as t o t he ac cept abl e di st ance bet ween m ul t i pl e sm al l ar eas. For ex am pl e, t he m i ni m um r equi r ed l i near di st ance s be t ween a 12" by 12" ar ea t hi nner t han 0.736" but t hi ck er t han 0.536" , and an ot her 12" by 12" ar ea t hi nner t han 0.736" b u t th ic k e r th a n 0.5 3 6", w e re n o t p ro v id e d. T he ac t ual dat a f or t wo bay s (13 and 1) sho ws t hat t her e i s m or e t han one 12" by 12" ar ea t hi nn er t ha n 0.73 6" bu t t hi c k er t ha n 0.53 6". Al s o t he ac t ua l da t a f or t wo bay s s hows t hat t her e i s m or e t han one 21/2 i n. di am et er ar ea t hi nner t han 0.736" but t hi ck er t han 0.490". Accept ance i s ba sed on t he f ol l owi ng ev al uat i on. T he e f f e c t o f th e s e v e ry lo c a li ze d w a ll th ic k n e s s a re a s o n th e b u c k li n g o f th e s h e ll r equi r es s om e di sc uss i on of t he buc kl i ng m echa ni sm i n a s hel l of r ev ol ut i on unde r a n a p p li e d a x ia l a n d la te ra l p re s s u re lo a d. T o begi n t he di sc uss i on, we wi l l des cr i be t he buc kl i ng of a si m pl y sup por t ed c y l i n d r i c a l s h e l l u n d e r t h e i n f l u e n c e o f l a t e r a l p r e s s u r e a n d a x i a l l o a d. As desc r i bed i n ch apt er 11 of t he T heor y of El ast i c St abi l i t y , Second Edi t i on, by T i m oshe nko and G er e, t hi n cy l i ndr i cal she l l s bu ck l e i n l obes i n bot h t he ax i al and ci r cum f er ent i al di r ect i ons. T hese l obes ar e def i ned as hal f wav e l engt hs o f si nuso i dal f unct i ons. T he f unct i ons ar e gov er ned by t he r adi us, t hi ck ness and l engt h of t he c y l i nder. I f we l ook at a sp eci f i c t hi n wal l ed c y l i ndr i cal she l l , bot h t hel engt h and r adi us wou l d be es sent i al l y con st ant s an d i f t he t hi ck ness was c hanged l ocal l y , t he c hange wo ul d hav e t o be s i gni f i cant and c ont i nuous ov er a m aj or i t y of t he l obe so t hat t he co m pr essi v e st r ess i n t he l obe wo ul d exceed t he cr i t i cal buckl i ng st r ess under t he appl i ed l oads , t her eby cau si ng t he s hel l t o buc kl e l ocal l y. T hi s ap pr oach can be easi l y ex t r apol at ed t o any she l l of r ev ol ut i on t hat woul d ex per i ence bot h an ax i al l oad and la te ra l p re s s u re a s in th e c a s e o f th e d ryw e ll. T h is lo c a l l o b e b u c k li n g is d e m o n s tra te d in t he G E Let t er R epo r t " S and bed Loca l T hi nni ng a nd R ai si ng t he F i x i t y H ei ght A nal y si s"wher e a 12 x 12 s quar e i nch sec t i on of t he dr y wel l san d bed r egi on i s r educ ed by 200 4-57 m i l s an d a l ocal buc kl e oc cur r ed i n t he f i ni t e el em ent ei genv al ue ex t r act i on anal y si s of t he dr y wel l. T her ef or e, t o i nf l uenc e t he buc kl i ng of a sh el l , t he v er y l ocal ar eas of r educ ed t hi ck ness woul d hav e t o be c ont i guous and of t he s am e t hi ck ness. T hi s i s al so c onsi st ent w ith C o d e C a s e 2 8 4 in S e c tio n-1 7 0 0 w h ic h in d ic a te s 'th a t th e a v e ra g e s tre s s v a lu e s in th e s h e ll s h o u ld b e u s e d f o r c a lc u la tin g th e b u c k li n g s tre s s. T h e re f o re , a n a c c e p ta b le di st ance bet ween ar eas of r educ ed t hi ck ness i s no t r equi r ed f or an ac cept abl e buc kl i ng anal y si s ex cept t hat t he ar ea of r educ ed t hi ck ness i s s m al l enough not t o i nf l uenc e a buck l i ng l obe of t he s hel l. T he v er y l ocal ar eas of t hi ck ness ar e di sper sed ov er a wi de ar ea wi t h v ar y i ng t hi ck ness and as suc h wi l l hav e a neg l i gi bl e ef f ect on t he buc kl i ng r espo nse of t he dr y wel l. I n addi t i on, t hese v er y l ocal wal l ar eas ar e ce nt er ed abou t t he v e n ts , w h ic h s ig n ific a n tly s tiff e n th e s h e ll. T h is s tiff e n in g e f f e c t li m its th e s h e ll b u c k li n g to a po i nt i n t he sh el l sand bed r egi on w hi ch i s l ocat ed a t t he m i dpo i nt bet we en t wo v ent s.T he a ccept ance cr i t er i a f or t he t hi ckness o f 0.49 i nche s conf i ned t o an ar ea l ess th a n 21/2 in c h e s in d ia m e te r e x p e rie n c in g p rim a ry m e m b ra n e + b e n d in g s tre s s e s is base d on ASM E B oi l er and Pr ess ur e Vesse l (B&PV) C ode, Sect i on I I I , Subsec t i on N E, C l ass MC C om ponent s, Par agr aphs N E-3213.2 G r oss St r uct ur al D i sc ont i nui t y , N E-3213.10 Loc al Pr i m ar y Mem br ane St r ess , N E-3332.1 O peni ngs not R equi r i ng Rei nf or cem ent , N E-3332.2 R equi r ed Ar ea of R ei nf or cem ent and N E-3 3 3 5.1 R e in f o rc e m e n t-o f M u lti p le O p e n in g s. T h e u s e o f P a ra g ra p h N E-3 3 3 2.1 is li m ite d b y th e re q u ire m e n ts o f P a ra g ra p h s N E-3 2 1 3.2 a n d N E-3 2 1 3.1 0. In par t i cul ar , N E-3213.10 l i m i t s t he m er i di onal di st ance bet ween ope ni ngs wi t hout re in f o rc e m e n t to 2.5 x (s q u a re ro o t o f R t). A ls o , P a ra g ra p h N E-3 3 3 5.1 o n ly appl i es t o openi ngs i n sh el l s t hat ar e cl oser t han t wo t i m es t hei r av er age di am et er. T he i m pl i cat i ons o f t hese par agr aph s ar e t hat shel l f ai l ur es at t hese l ocat i ons f r om pr i m ar y st r ess es p r oduc ed by pr ess ur e ca nnot occ ur pr ov i ded openi ngs i n sh el l s ha v e su f f i ci ent r ei nf or cem ent. T he c ur r ent des i gn pr ess ur e of 44 ps i g f or t he dr y wel l r equi r es a t hi ck ness of 0.479 i nche s i n t he s and bed r egi on of t he dr y wel l. A r ev i ew of al l t he UT dat a pr esen t ed i n Appendi x D of t he cal cul at i on i ndi cat es t hat al l t hi ck ness es i n t he dr y wel l san d bed r egi on ex ceed t he r equi r ed pr ess ur e t hi ck ness by a su bst ant i al m ar gi n. T her ef or e, t he re q u i re m e n ts fo r p re s s u re re i n fo rc e m e n t s p e c i fie d i n th e p re v i o u s p a ra g ra p h a re not r equi r ed f or t he v er y l ocal wal l t hi ck ness ev al uat i on pr esen t ed i n R ev i si on 0 of C al cul at i on C-1302-187-5320-024.Re v i e w i n g t h e s t a b i l i t y a n a l y s e s p r o v i d e d i n b o t h t h e GE Re p o r t 9-4 a n d t h e GE L e tte r R e p o rt, "S a n d b e d L o c a l T h in n in g a n d R a is in g th e F ix ity H e ig h t A n a ly s is ,"and r ecog ni z i ng t hat t he pl at e el em ent s i n t he s and bed r egi on of t he m odel ar e 3" x 3", i t i s c l e a r th a t t h e c i rc u m fe re n ti a l b u c k l i n g l o b e s fo r th e d ry w e l l a re subst ant i al l y l ar ger t han t he 21/2 i nch d i am et er v er y l ocal wa l l ar eas. T hi s, com bi ned wi t h t he l ocal r ei nf or cem ent sur r oundi ng t hese l ocal ar eas, i ndi cat es t hat t hese ar eas w i l l have no i m pact on t he b uckl i ng m ar gi ns i n t he sh el l. I t i s al so cl ear f r om t he G E Let t er R epor t t hat a uni f or m r educ t i on i n t hi ck ness of 27 per cent to 0.5 3 6" o v e r a o n e s q u a re f o o t a re a w o u ld o n ly c re a te a 9.5 p e rc e n t re d u c tio n in t he l oad f act or and t heor et i cal buc kl i ng s t r ess f or t he whol e dr y wel l r esul t i ng i n t he l ar gest r educ t i on pos si bl e. I n addi t i on t o t he r epor t ed r esul t f or t he 27 p er cent re d u c tio n in w a ll th ic k n e s s , a s e c o n d b u c k li n g a n a ly s is w a s p e rf o rm e d f o r a w a ll th ic k n e s s re d u c tio n o f 1 3.5 p e rc e n t o v e r a o n e s q u a re f o o t a re a w h ic h o n ly 4-58 r educ ed t he l oad f act or and t heor et i cal buc kl i ng s t r ess by 3.5 per cent f or t he w h o le d ryw e ll , re s u lti n g in th e la rg e s t re d u c tio n p o s s ib le. T o b rin g th e s e re s u lts in to p e rs p e c tiv e , a re v ie w o f th e n o n d e s tru c tiv e e x a m in a tio n (N D E) re p o rts i ndi cat es t hat t her e ar e 20 UT m easu r ed ar eas i n t he whol e sa nd bed r egi on t hat h a v e th i c k n e s s e s l e s s th a n th e 0.7 3 6 i n c h u s e d i n G E R e p o rt 9-4 , w h i c h c o v e r a cons er v at i v e t ot al ar ea of 0.68 s quar e f eet of t he dr y wel l sur f ace wi t h an av er age th ic k n e s s o f 0.7 0 3" o r a 4.5 p e rc e n t re d u c tio n in w a ll th ic k n e s s. T her ef or e, t o ef f ect i v el y cha nge t he buc kl i ng m ar gi ns o n t he dr y wel l she l l i n t he sand bed r egi on a r educ ed t hi ck ness woul d hav e t o co v er appr ox i m at el y one s q u a re f o o t o f s h e ll a re a a t a lo c a tio n in th e s h e ll th a t is m o s t s u s c e p tib le to buck l i ng wi t h a r educ t i on i n t hi ck ness gr eat er t han 25 per cent. T hi s l eads t o t he conc l usi on t hat t he buc kl i ng of t he s hel l i s un af f ect ed by t he di st ance bet ween t he v er y l ocal wal l t hi ck ness es, i n f act t hese l ocal ar eas coul d be c ont i guous pr ov i ded t hei r t ot al ar ea di d not ex ceed one s quar e f oot and t hei r av er age t hi ck ness was gr eat er t han t he t hi ck ness anal y z ed i n t he G E Let t er R epor t , and pr ov i ded t he m e th o d o lo g y o f C o d e C a s e N 2 8 4 w a s e m p lo ye d to d e te rm in e th e a ll o w a b le b u c k l i n g l o a d fo r th e d ry w e l l. F u rth e rm o re , a l l o f th e s e v e ry l o c a l w a l l a re a s a re cent er ed a bou t t he vent s, wh i ch si gni f i cant l y st i f f en t he sh el l. T hi s st i f f eni ng e f f ect l i m i t s t he s hel l buc kl i ng t o a poi nt i n t he s hel l san d bed r egi on, whi ch i s l ocat ed at t he m i dpo i nt bet we en t wo v ent s.I n su m m ar y , t he appl i cant not ed t hat t he m i ni m um r equi r ed dr y wel l she l l t hi ck ness i s ba sed on a n a n a ly s is c o n d u c te d in a c c o rd a n c e w ith A S M E C o d e. F a c to rs c o n s id e re d in c lu d e d ryw e ll g e o m e try, m a te ria l o f c o n s tru c tio n , re d u c e d w a ll th ic k n e s s d u e to c o rro s io n , a n d a p p li c a b le desi gn-basi s l oads and l oad c om bi nat i ons. Acci dent pr ess ur e and t em per at ur e ar e 44 ps i g and 292 E F, r espe ct i v el y , i n ac cor danc e wi t h t he appr ov ed t echn i cal spe ci f i cat i on am endm ent N o. 1 6 5. I n a l et t er dat ed Apr i l 7, 2006, t he appl i cant r espo nded t o R AI 4.7.2-1. I n i t s r espo nse t he appl i cant st at ed t hat t he m i ni m um r equi r ed t hi ck ness es o f t he dr y wel l she l l abov e t he s and bed r egi on s hown i n T abl e-1 of t he r espo nse ar e co nt r ol l ed by m em br ane s t r ess es. T he m i ni m um r equi r ed gene r al dr y wel l she l l t hi ck ness i n t he s and bed r egi on of 0.736 i nch i s c ont r ol l ed by b u c k l i n g. L o c a l i ze d a re a s i n th e s a n d b e d re g i o n w h e re th e th i c k n e s s i s l e s s th a n 0.7 3 6 i n c h a re e v a l u a t e d a g a i n s t a l o c a l t h i c k n e s s a c c e p t a n c e c r i t e r i a (0.4 9 i n c h) d e v e l o p e d b a s e d o n ASM E C ode , S ect i on I I I , S ubse ct i on N E , C l ass M C C om pon ent s, P ar agr aph s N E-321 3.2, "G r oss St r uct ur al D i sc ont i nui t y ," N E-3213.10, "Loca l Pr i m ar y Mem br ane St r ess ," N E-3332.1, "O peni ngs N ot R equi r i ng Rei nf or cem ent ," N E-3332.2, "R equi r ed Ar ea of R ei nf or cem ent ," and NE-3335.1,"R ei nf or cem ent of Mul t i pl e O peni ngs." Appl i cat i on of t hese AS M E C ode s ect i ons i s j ust i f i ed as di sc uss ed abov e, and s peci f i c bu ck l i ng s ensi t i v i t y anal y si s r esul t s s uppor t t he c oncl usi on t hat , on an a v er age wa l l t hi ckness b asi s, buckl i ng o f t he sh el l i s una f f ect ed b y l ocal wa l l t hi ckness ar eas as t hese ar e di st r i but ed ov er t he s and bed r egi on.T he s t af f r ev i ewed t he c i t ed anal y si s r epor t s t o ens ur e t hat t he par am et er s us ed and t he a s s u m p ti o n s m a d e i n th e a n a l y s i s a re v a l i d fo r th e p e ri o d o f e x te n d e d o p e ra ti o n. H o w e v e r, base d on t he r ev i ew con duct ed, t he s t af f r eques t ed t hat t he appl i cant pr ov i de addi t i onal i nf or m at i on t o ad dr ess cer t ai n gr oss assu m pt i ons.At t achm ent 1A of t he G PU l et t er dat ed Nov em ber 26, 1990, m akes a st at i st i cal ev al uat i on of t he U T m easu r em ent dat a t aken up t o 1990. O n t he c ov er page o f t he r epor t , G PU N ucl ear 4-59 Co r p o r a t i o n s t a t e s a d i s c l a i me r , "t h e w o r k i s c o n d u c t e d b y a n i n d i v i d u a l (s) f o r u s e b y GP U.N e ith e r G P U n o r th e a u th o rs o f th e re p o rt w a rra n t th a t th e re p o rt is c o m p le te o f a c c u ra te -." In v ie w o f th is d is c la im e r, th e s ta f f a t a p u b li c m e e tin g o n J u n e 1 , 2 0 0 6 , a s k e d th e a p p li c a n t to pr ov i de a de t ai l ed des cr i pt i on of t he way t he UT m easu r em ent dat a, whet her t aken as p ar t of t he 6-in c h b y 6-in c h g rid , o r is o la te d re a d in g s , w e re e v a lu a te d a n d u s e d in p e rf o rm in g th e a n a ly s is. I n i t s r espo nse dat ed J une 20, 2006, t he appl i cant cl ar i f i ed t he us e of t he s t at i st i cal ev al uat i on as f ol l ow s: T h e d is c la im e r n o te d b y th e N R C s ta f f is o n th e c o v e r p a g e o f T e c h n ic a l D a ta R epo r t (T D R) N o. 948 R evi si on 1 , " S t at i st i cal A nal y si s of t he D r y we l l T hi ckness Da t a." Th e d i s c l a i me r s t a t e me n t i s a s t a n d a r d c l a u s e t h a t w a s p l a c e d o n TDR s dev el oped i n ac cor danc e wi t h t he appl i cabl e G PU N pr oced ur e at t he t i m e.Am er G en poi nt s ou t t hat T D R N o. 1027, whi ch i s al so a par t of At t achm ent 1A i n c l u d e s t h e s a me d i s c l a i me r. Th e d i s c l a i me r w a s i n t e n d e d t o r e i n f o r c e t h a t TDR s a re n o t d e s ig n b a s is d o c u m e n ts a n d w e re n o t d e s ig n v e rif ie d in a c c o rd a n c e w ith t he G PU N Q A P r ogr am. I n t hi s c ase T D R 948 was dev el oped t o su m m ar i z e t he i ni t i at i v e t hat sur v ey ed t he dr y wel l and t hat ass ess ed i ni t i al cor r osi on r at es b ased on dat a co l l ect ed f r om 1986 t hr ough Decem ber 1988. H owev er t hi s TD R di d not ser v e as t he des i gn bas i s do cum ent , whi ch d em onst r at ed t he dr y wel l she l l m et desi gn bas i s r equi r em ent s. T he T D R i n Sect i on 1 (I nt r oduc t i on/Backgr ound)ex pl ai ns t hat t he T D R doc um ent s t he as sum pt i ons, m et hods and r esul t s of t he st at i st i cal anal y si s us ed t o ev al uat e t he c or r osi on r at es. T he s ect i on t hen s t at es t hat t he c om pl et e anal y si s i s do cum ent ed i n ca l cul at i on C-1302-187-5300-005.
C al cul at i on C-130 2-187-530 0-005 , " S t at i st i cal A nal y si s of D r y we l l T hi ckness D at a T hr u 12-31-88" di d ser v e as t he d esi gn b asi s docu m ent , wh i ch dem onst r at ed t he dr y wel l she l l m et des i gn bas i s r equi r em ent s. T hi s c al cul at i on was de v el oped an d des i gn v er i f i ed i n ac cor danc e wi t h t he G PU N Q A P r ogr am a n d is a p p ro x im a te ly 2 0 0 p a g e s lo n g. A re v ie w o f th e in f o rm a tio n c o n ta in e d in th e T D R S e c tio n 4.6 (S u m m a ry o f C o n c lu s io n) s h o w s th a t it i s c o n s is te n t w ith t he i nf or m at i on i n Sect i on 2 (Sum m ar y of R esul t s) i n ca l cul at i on C-1 3 0 2-0 1 8 7-5 3 0 0-0 0 5. T h u s , th e in f o rm a tio n in th e T D R N o. 9 4 8 re p re s e n ts d e s ig n q u a li ty i n f o rm a tio n. In re s p o n s e to th e N R C's q u e s ti o n o n h o w th e U T m e a s u re m e n t d a ta w e re ev al uat ed and used i n t he dr y wel l anal y si s, Am er G en pr ov i ded a d esc r i pt i on of h o w t h e 4 9-p o i n t a r r a y s t a t i s t i c a l a n a l y s i s w a s p e r f o r me d i n r e s p o n s e t o NR C Q&A #AM P-356, i t em (4). I n t hat r espo nse, Am er G en s t at ed t hat t he m et hodol ogy and accep t ance cr i t er i a t hat ar e ap pl i ed t o ea ch gr i d of poi nt t hi ckness r ead i ngs, i ncl udi ng bot h gl obal (ent i r e ar r ay) ev al uat i on and l ocal(s u b re g io n o f a rra y) a re d e s c rib e d in e n g in e e rin g s p e c ific a tio n IS-3 2 8 2 2 7-0 0 4 a n d in c a lc u la tio n N o. C-1 3 0 2-1 8 7-5 3 0 0-0 1 1 , "S ta tis tic a l A n a ly s is o f D ryw e ll T h ic k n e s s D a ta T hr u 4-24-90". T hi s c al cul at i on i s t he m or e r ecen t v er si on of cal cul at i on C-1302-187-5300 a n d h a s b e e n s u b mi t t e d b y A me r Ge n t o t h e NR C.T hese t wo doc um ent s wer e su bm i t t ed t o t he NR C i n a l et t er dat ed N ov em ber 26, 1990 a nd pr ov i ded t o t he St af f dur i ng t he AM P/AM R audi t. A br i ef s umm ar y of t he m et ho do l og y an d a c c ep t an c e c r i t er i a i s de s c r i be d b el ow.
4-60T he i ni t i al l ocat i ons i den t i f i ed i n 19 86 a nd 1 987 wh er e cor r osi on l oss w as m ost sever e w er e sel ect ed f or r epe at i nspe ct i on o v er t i m e t o m easu r e cor r osi on r at es.F o r l o c a t i o n s w h e r e t h e i n i t i a l i n v e s t i g a t i o n s f o u n d s i g n i f i c a n t w a l l t h i n n i n g , UT i nspe ct i on c onsi st ed of 49 i ndi v i dual U T dat a poi nt s eq ual l y spa ced ov er a 6" x 6" ar ea. Each new s et of 49 v al ues was t hen t est ed f or nor m al di st r i but i on. I f t he dat a was nor m al l y di st r i but ed, t hen t he m ean v al ue of t he 49 p oi nt s was cal cul at ed and used t o r epr esen t t he gene r al dr y wel l she l l t hi ck ness i n t he t est ed ar ea. I f t he 49 p oi nt s wer e not nor m al l y di st r i but ed, t hen t he gr i d was subd i v i ded i nt o dat aset s (usua l l y 2, t op and bot t om) t hat wer e nor m al l y di st r i but ed. T he m ean v al ue f or eac h dat aset was t hen c al cul at ed. T he m i ni m um m ean v al ue was c ompar ed t o t he m i ni m um r eq ui r ed t hi c k ne s s as de s c r i be d b el ow.T he m ean v al ues of eac h gr i d wer e t hen c om par ed t o t he r equi r ed m i ni m um uni f or m t hi ck ness cr i t er i a of 0.736 i nche s. I n addi t i on eac h i ndi v i dual r eadi ng was com par ed t o t he l ocal m i ni m um r equi r ed c r i t er i a of 0.490 i nche s. T he bas i s f or t he r equi r ed m i ni m um uni f or m t hi ck ness cr i t er i a and t he l ocal m i ni m um r equi r ed cr i t er i a i s pr ov i ded i n r espo nse t o N R C Q uest i on #AM P-210. A decr ease i n t he m e a n v a lu e o v e r tim e is re p re s e n ta tiv e o f c o rro s io n. If c o rro s io n d o e s n o t e x is t, t h e me a n v a l u e w i l l n o t v a r y w i t h t i me , a l t h o u g h r a n d o m v a r i a t i o n s i n t h e UT m easu r em ent s as a r esul t of such f act or s as var i abl es i n t he i nspe ct i on p r ocess and i n env i r onm ent al con di t i ons m ay occ ur. I f cor r osi on i s c ont i nui ng, t he m ean th ic k n e s s w il l d e c re a s e li n e a rly w ith tim e. T h e re f o re th e c u rv e f it o f th e d a ta is t est ed t o det er m i ne i f l i near r egr ess i on i s ap pr opr i at e, i n whi ch c ase t he c or r osi on r at e i s eq ual t o t he s l ope of t he l i ne. I f a sl ope ex i st s, t hen upp er and l ower 95%conf i den ce i nt er v al s of t he cu r v e f i t ar e cal cul at ed. T he l ow er 95% conf i den ce i nt er v al i s t hen pr oj ect ed i nt o t he f ut ur e and c om par ed t o t he r equi r ed m i ni m um u n ifo rm th ic k n e s s c rite ria o f 0.7 3 6 in c h e s. A pr oces s s i m i l ar t o t hat des cr i bed abo v e i s ap pl i ed t o t he t hi nnes t i ndi v i dual r eadi ng i n eac h gr i d. T he l owest r eadi ng t aken i s al so v er i f i ed agai nst t he l ocal m in im u m th ic k n e s s re q u ire m e n t. T h e n th e c u rv e f it o f th e d a ta is te s te d to det er m i ne i f l i near r egr ess i on i s ap pr opr i at e. I f a sl ope ex i st s, t hen t he l ower 95%conf i denc e i nt er v al i s t hen pr oj ect ed i nt o t he f ut ur e and c om par ed t o t he r equi r ed m in im u m lo c a l th ic k n e s s c rite ria o f 0.4 9 0 in c h e s. T he s t af f f i nds t hat t he appl i cant has pr ov i ded an ex pl anat i on of t he doc um ent s us ed f or t he desi gn bas i s c al cul at i ons. Fur t her m or e, t he appl i cant pr ov i ded t he pr oces s us ed i n es t abl i shi ng t he m i ni m um t hi ck ness of t he dr y wel l use d i n t he 1991 G E anal y si s. Based on t he di sc uss i on pr ov i ded abo v e, t he s t af f f i nds t he appl i cant's hi st or i cal m et hod of det er m i ni ng t he m i ni m um r equi r ed wal l t hi ck ness acc ept abl e bec ause t hese pr oces ses use r ecog ni z ed i ndus t r y st andar ds f or per f or m ance and ev al uat i on of r esul t s. O n t he bas i s of t he appl i cant's wr i t t en r espo nse, t he st af f det er m i ned t hat i t s c once r ns r el at ed t o t he di sc l ai m er i n t he T echn i cal D at a R epor t had b e e n re s o lv e d.
O pen I t em 4.7.2-1.3: AS M E C ode Case N-284 I n t he appl i cant's di sc uss i on, a su m m ar y of t he m et hods and as sum pt i ons used i n t he buc kl i ng a n a l y s i s o f t h e s h e l l i n t h e s a n d-p o c k e t a r e a h a s b e e n g i v e n. Th o u g h i t h a s n o t e n d o r s e d ASM E C o d e C a s e N-2 8 4 for u s e , t h e s t a ff d o e s n o t t a k e e xc e p t i o n t o t h e u s e o f ave r a g e c o m p r e s s i ve st r ess acr oss t he m et al t hi ck ness f or buc kl i ng anal y si s of t he as-bui l t she l l. H owev er , i f t he 4-61 c o rro s io n h a s re d u c e d th e s tre n g th o f th e re m a in in g m e ta l th ro u g h th e c ro s s s e c tio n , th is a s s u m p tio n m a y n o t b e v a li d. T h e s ta f f re q u e s ts th e a p p li c a n t to a d d re s s th is is s u e. I n i t s r espo nse d at ed Ju ne 2 0, 200 6, t he a ppl i cant pr ovi ded t he f ol l ow i ng d i scussi on o n t he u se of AS M E C ode Case N-284:Al t hough Rev i si on 1 of C ode Case 284 had not y et been i ss ued when t he R ef er ence 2 r epor t (An A SM E S ect i on VI I I Ev al uat i on of O y st er C r eek D r y wel l f or W i t hout Sand C ase, Par t I I - St abi l i t y Anal y si s," G E R epor t , I ndex N o. 9-4, R ev i si on 0, D R F # 00664) was wr i t t en, t he aut hor s ha d t he bene f i t of con sul t at i on wi t h D r. C l ar ence Mi l l er who was t he pr i m ar y aut hor of t he r ev i si on. T hus, t he pl ast i ci t y cor r ect i on f act or s us ed i n t he ev al uat i on (i n Fi gur e 2-4 of R ef er ence 2)a re th e s a m e a s th o s e in F ig u re 1 6 1 0-1 o f C o d e C a s e N-2 8 4 R e v is io n 1. Par agr aph 150 0 i n bot h r ev i si ons al l ows hi gher v al ues of cap aci t y r educ t i on f act or s du e t o i nt er nal pr ess ur e by st at i ng, " T he i nf l uenc e of i nt er nal pr ess ur e on a shel l st r uct ur e m ay r educ e t he i ni t i al i m per f ect i ons and t her ef or e hi gher v al ues of ij capa ci t y r edu ct i on f act or s á m ay be ac cept abl e. Jus t i f i cat i on f or hi gher v al ues of ijá m ust be gi v en i n t he des i gn r epor t." T he t echn i cal appr oach doc um ent ed and u s e d in th e R e f e re n c e 2 a n a ly s is w a s re v ie w e d a n d a c c e p te d b y D r. M il le r in R ef er ence 4 (M i l l er , C.D., 1991, " Ev al uat i on of St abi l i t y Anal y si s Met hods U sed f o r t h e Oy s t e r Cr e e k Dr y w e l l ," Do c k e t No. 5 0-2 1 9 , Se p t e m b e r 1 2 , 1 9 9 1 , CBI T echn i cal Ser v i ces C om pany R epor t pr epar ed f or G PU N ucl ear C or por at i on). t hat i s al so c i t ed as one of t he r ef er ence s i n R ef er ence 3 r epor t (N U R EG/C R-6706" C apac i t y of St eel and Concr et e C ont ai nm ent Vessel s W i t h C or r osi on D a m a g e ,"F e b ru a ry 2 0 0 1").T h u s , th e te c h n ic a l a p p ro a c h u s e d in th e s ta b il ity e v a lu a tio n o f R e f e re n c e 2 is ent i r el y con si st ent wi t h t he gui del i nes i n R ev i si on 1 of C ode Case N-284.In th e R e fe re n c e 6 re p o rt (M i l l e r, C.D., "A p p l i c a b i l i ty o f A S M E C o d e C a s e N-2 8 4-1 t o Buckl i ng Anal y si s of D r y wel l Shel l ," Jun e 15, 2006), D r. Mi l l er di sc uss ed t he appl i cabi l i t y of t he N-284-1 m et hods t o co r r oded s hel l s. H e i ndi cat ed t hat t he im p e rf e c tio n li m it i n d ic a te d b y a p a ra m e te r e/t (w h e re 'e' is th e e c c e n tric ity a n d 't'i s t he s hel l t hi ck ness) was a ss um ed as 1.0 i n C ode Case N-284-1. T he i m per f ect i ons coul d be f r om t he f abr i cat i on pr oces s i n t he c ase of a new s hel l or c o u ld b e f ro m a c o m b in a tio n o f f a b ric a tio n a n d c o rro s io n in th e s h e ll s a lre a d y i n ser v i ce. T he co nt r i but i on t o e/t par am et er f r om cor r osi on w as de f i ned as f ol l ow s: cor r osi on n c c (e/t) = (t - t)/(2t)Fo r t he sa nd b ed r egi on, i f we assum e t he m i ni m um gen er al cor r ode d t hi ckness cor r osi on of 0.736 i nch and t he nom i nal t hi ck ness of 1.154 i nche s, t he (e/t) wor ks out t o be (1.154-0.736)/(2x 0.736) or 0.28. H owev er , t hi s do es n ot m ean t he pr eced i ng cor r osi on v al ue o f (e/t) nee d al wa y s be a dde d t o t he (e/t) v al ue f r om f abr i cat i on. I n f act i t needs t o be s ubt r act ed wher e t he f abr i cat i on r el at ed ec cent r i ci t y i s i n t he o u tw a rd ra d ia l d ire c tio n. S in c e th e f a b ric a tio n re la te d e c c e n tric iti e s a re li k e ly r andom l y di st r i but ed and t hus ar e equal l y l i ke i n ei t her di r ect i on, t he ov er al l net e f f e c t o f th e c o rro s io n-in d u c e d e c c e n tric iti e s w o u ld b e in s ig n ific a n t. T h u s , it i s concl ude d t hat t he co r r osi on o n t he o ut si de su r f ace o f t he sh el l wi l l not i nt r odu ce 4-62 ecc ent r i ci t i es t hat woul d si gni f i cant l y i m pact t he e/t v al ue of 1.0 as sum ed i n C ode C ase N-284.A s a s u m m a ry, th e a p p li c a n t s ta te d: T he st r ess an al y si s of O y st er C r eek d r y we l l sat i sf i es t he l ocal pr i m ar y st r ess r equ i r em ent s of N E-321 3.10. C onse r v at i sm i n t he a l l ow abl e pr i m ar y st r ess i nt ensi t y v al ue, t he as sum ed peak pr ess ur e dur i ng t he LO C A condi t i on and t he ass um pt i on of l ocal cor r oded t hi ck ness i n t he ent i r e r egi on of t he dr y wel l pr ov i de addi t i onal st r uct ur al m ar gi n.Si nce t he Code pr i m ar y st r ess l i m i t s ar e sa t i sf i ed i n t he c or r oded c ondi t i on and t he num ber of f at i gue c y cl es i s s m al l , t he s ur f ace di sc ont i nui t i es f r om cor r osi on do not r epr esen t a si gni f i cant st r uct ur al i nt egr i t y con cer n.T h e te c h n ic a l a p p ro a c h u s e d in th e s ta b il ity e v a lu a tio n o f th e O ys te r C re e k d ryw e ll i s c onsi st ent wi t h t he r equi r em ent s s peci f i ed i n C ode Case N-284, R ev i si on 1.Addi t i onal ecc ent r i ci t y pr oduc ed by she l l cor r osi on i n se r v i ce i s ex pect ed t o be accom m oda t ed w i t hi n t he a l l ow abl e l i m i t f or i m per f ect i ons.As i ndi cat ed i n T abl e-1, U T m easu r em ent s of t he dr y wel l she l l abov e t he s and bed r egi on s how t hat t he m easu r ed gene r al t hi ck ness con t ai ns s i gni f i cant m ar gi n.C onsi der i ng t he ongo i ng c or r osi on i n t hat r egi on i s i nsi gni f i cant , t he m ar gi n ca n be app l i ed t o of f set unce r t ai nt i es r el at ed t o sur f ace r oug hne ss.U T m easu r em ent s of t he dr y wel l she l l i n t he s and bed r egi on s how t hat t he m e a s u re d g e n e ra l th ic k n e s s is g re a te r th a n th e 0.7 3 6 in c h th ic k n e s s a s s u m e d in t he buc kl i ng anal y si s by si gni f i cant m ar gi n ex cept i n 2 bay s, bay #17 an d bay #19.(R ef er t o r espo nse t o R AI 4.7.2-1(d), T abl e-2). T he m ar gi n i n t he gene r al t hi ck ness of t he t wo bay s i s 0.074 i nch and 0.064 i nch r espe ct i v el y. C onsi der i ng t hat si gni f i cant addi t i onal cor r osi on i s no t ex pect ed i n t he s and bed r egi on, t he m ar gi n can be a ppl i ed t o of f set unce r t ai nt i es r el at ed t o t he su r f ace r oug hne ss.T he s t af f f i nds t hat t he appl i cant has pr ov i ded a t hor ough ex pl anat i on of t he f act or s c onsi der ed i n appl y i ng t he AS M E C ode Case N-284-1 f or buc kl i ng anal y si s of t he c or r oded s hel l i n t he s and b e d a re a o f th e d ryw e ll s h e ll. H o w e v e r, it d o e s n o t a d d re s s th e s ta f f's c o n c e rn a b o u t w h e th e r it is appr opr i at e t o as sum e t he s am e st r engt h ac r oss t he c or r oded s ect i on of t he s hel l. T he in c o rp o ra tio n o f th e "e/t" c o rro s io n c o n c e p t to a rriv e a t a re p re s e n ta tiv e d is trib u tio n o f s tre n g th a lo n g th e c o rro d e d s e c tio n th a t re c o g n ize s th e lo w e r s tre n g th a t th e c o rro d e d s id e a n d f u ll st r engt h at t he i nsi de s ur f ace coul d su ppor t t he c l ai m of con ser v at i sm i n t he anal y si s. T hi s was i dent i f i ed as O I 4.7.2-1.3 i n t he SE R , dat ed August 18, 2006.O n f u rth e r e v a lu a tio n o f th e a p p li c a n t's in f o rm a tio n , th e s ta f f c o n c lu d e s th a t th e s ta b il ity e v a l u a ti o n w a s c o n s i s te n t w i th th e g u i d e l i n e s o f A S M E C o d e C a s e N-2 8 4-1. T h e s ta ff's c o n c e rn about use of t he s am e se ct i on s t r engt h ac r oss t he c or r oded s ect i on of t he s hel l i s ad dr ess ed by th e C o d e C a s e N-2 8 4-1 , w h ic h u s e s c o n s e rv a tiv e a s s u m p tio n s to d e te rm in e s h e ll c a p a c ity r edu ct i on f act or s (i.e., a s s u m p tio n o f im p e rf e c tio n li m it i n d ic a te d b y p a ra m e te r "e/t" to b e 1.0 in th e c o d e c a s e) e x p e c te d to c o m p e n s a te re a s o n a b ly f o r s u c h u s e o f s a m e s e c tio n s tre n g th. In a d d iti o n , th e a p p li c a n t c o n s e rv a tiv e ly a s s u m e d th e lo c a l c o rro d e d th ic k n e s s f o r th e e n tire d ryw e ll s h e ll re g io n a n d d e m o n s tra te d th a t th e c o d e a ll o w a b le s tre s s e s w e re s a tis f ie d c o n s is te n tly w ith 4-63 th e g u id e li n e s o f th e c o d e c a s e. T h u s , th is a n a ly s is a d d s a m a rg in o f s a f e ty fo r th e d ryw e ll s ta b il ity e v a lu a tio n. O n th is b a s is , th e s ta f f b e li e v e s th a t th e s ta b il ity e v a lu a tio n m e th o d is adequa t e and a cc ept abl e, and t he s t af f's c once r n i s r esol v ed. O pen I t em 4.7.2-1.3 i s c l osed.
O pen I t em 4.7.2-1.4: Loc al i z ed T hi n Ar eas F o r t h e l o c a l i z e d t h i n a r e a s , t h e a p p l i c a n t i s u s i n g t h e p r o v i s i o n o f NE-3 2 1 3.1 0 o f S u b s e c t i o n NE o f S e c tio n III o f th e A S M E C o d e. T h is p ro v is io n , a lth o u g h n o t d ire c tly a p p li c a b le to th e ra n d o m ly t hi n ar eas caus ed by cor r osi on, i f use d wi t h ca r e and a dequat e co nser v at i sm , m ay pr ov i de s om e i d e a a b o u t t h e p ri m a ry s t re s s l e ve l s a t t h e j u n c t i o n o f t h e t h i n a n d t h i c k a re a s. T h e s t a ff re q u e s te d th a t th e a p p li c a n t p ro v id e a s u m m a ry o f th e p ro c e s s u s e d to a d d re s s th is is s u e. In its re s p o n s e d a te d J u n e 2 0 , 2 0 0 6 , th e a p p li c a n t n o te d th a t th is is th e o n ly m e th o d a v a il a b le and t hat t hi s ap pr oach was a cc ept ed by t he s t af f i n t he 1990 s. R ecen t l y , t he appl i cant had cont r act ed G E t o r ev i ew t he 1991 anal y si s f or t he pur pose of i dent i f y i ng c onse r v at i sm. T he app l i cant sum m ar i z ed t he G E r epo r t as f ol l ow s:Al t hough t he AS M E S ect i on I I I and Sect i on VI I I anal y si s pr oced ur es wer e not dev el oped f or r andom l y t hi n ar eas caus ed by cor r osi on, G E has co ncl uded t hat t he s am e anal y si s pr oced ur es a r e appl i cabl e t o i n-ser v i ce c om ponent s as l ong as th e s e c tio n th ic k n e s s v a lu e s u s e d a re a d ju s te d to a c c o u n t fo r th e re d u c tio n d u e to cor r osi on. T abl e 2-1 of R ef er ence 1 l i st s t he nom i nal t hi ck ness v al ues and t he 95% con f i denc e l ev el t hi ck ness v al ues i n t he l ocal l y cor r oded ar eas. Ev en t hough t he c or r oded t hi ck ness i s pr esen t onl y i n a v er y l ocal ar ea of a r egi on, t he r educ ed v al ue w as use d f or t hat dr y we l l r egi on i n t he S ect i on V I I I st r ess an al y si s.AS M E S ect i on I I I , Subsec t i on NE-3213.10 s t at es t hat m em br ane s t r ess pr oduc ed by pr ess ur e or ot her m echa ni cal l oadi ng and ass oci at ed wi t h a pr i m ar y or di sc ont i nui t y ef f ect pr oduc es e x ces si v e di st or t i on i n t he t r ansf er of l oad t o ot her por t i ons o f t he st r uct ur e. C onse r v at i sm r equ i r es t hat such st r ess be cl assi f i ed a s a l o c a l p ri m a ry m e m b ra n e s t re s s e ve n t h o u g h i t h a s s o m e c h a ra c t e ri s t i c s o f a sec ondar y st r ess. A st r ess ed r egi on m ay be c onsi der ed l ocal i f t he di st ance ov er mc whi ch t he m em br ane ex ceed s 1.1 S (st r ess i nt ensi t y) does not ex t end i n t he mc m er i di onal di r ect i on m or e t han 1.0(R t)1/2, wher e S i s as def i ned i n Subsec t i on N E-3112.4, R i s t he m i ni m um m i d su r f ace r adi us o f cur v at ur e and t i s t he m i ni m um t hi ckness i n t he r egi on co nsi der ed. R egi ons o f l ocal pr i m ar y st r ess mc i nt ensi t y i nv ol v i ng ax i sy m m et r i c m em br ane di st r i but i ons whi ch e x ceed 1.1S shal l not be c l oser i n t he m er i di onal di r ect i on t han 2.5 (R t)1/2, wher e R i s de f i ned as (R 1 + R2)/2 and t i s de f i ned as (t 1 + t 2)/2, wher e t 1 and t 2 ar e t he m i ni m um t hi ck ness es a t eac h of t he r egi ons cons i der ed and R 1 and R2 ar e t he m i ni m um m id s u rf a c e ra d ii o f c u rv a tu re a t th e s e re g io n s w h e re th e m e m b ra n e s tre s s in te n s ity e x c e e d s 1.1 mc S. T he r equi r em ent s of AS M E S ect i on I I I , Subsec t i on NE-3213.10 wer e sa t i sf i ed by det er m i ni ng t he m ax i m um m er i di onal ex t ent of t he ar eas wher e t he l ocal pr i m ar y m em br ane mc mc st r ess ex ceed s 1.1 S , but i s be l ow t he al l owabl e v al ue of 1.5 S [R ef er ence 1]. T he m ax i m um e x te n t w a s d e te rm in e d to b e 1 1 in c h e s (u s in g th e la rg e d is p la c e m e n t s o lu tio n) a n d w a s f o u n d to b e a c c e p ta b le [i.e., le s s th a n th e a ll o w a b le v a lu e o f 1.0 (R t)1/2 o r 1 7.6 in c h e s]. G iv e n th a t a uni f or m m i ni m um cor r oded t hi ck ness f or a dr y wel l r egi on i s us ed i n t he ev al uat i on, t he pr eced i ng anal y si s i s ex pect ed t o be bo undi ng f or t he ac t ual cor r oded c ondi t i on.T he appl i cant not es t hat t he abov e ev al uat i on was bas ed on a peak i nt er nal pr ess ur e of 62 ps i. H owev er , t he appl i cant poi nt s ou t t hat t he O y st er C r eek 4-64 spec i f i c c al cul at i on wi t h an ad der of 15% sho wed t he peak i nt er nal pr ess ur e as 44 psi , and t hat t hi s v al ue was appr ov ed by t he NR C i n 1993. T he appl i cant not ed t hat " al t hough p r ov i si ons i n AS M E C ode Sect i on I I I , Subsec t i on N E-3213.10 ar e not di r ect l y appl i cabl e t o t he r andom l y t hi n ar eas caus ed by cor r osi on, Am er G en bel i ev es t hat t he pr ov i si ons ar e appl i cabl e t o t he anal y si s of O y st er C r eek dr y wel l she l l bas ed on t he f ol l owi ng:
- T he s t r ess anal y si s of O y st er C r eek dr y wel l pr esen t ed i n R ef er ence 1 sa t i sf i es t he l ocal pr i m ar y st r ess r equ i r em ent s of N E-321 3.10. C onse r v at i sm i n t he a l l ow abl e pr i m ar y st r ess i nt ensi t y v al ue, t he as sum ed peak pr ess ur e dur i ng t he LO C A condi t i on and t he ass um pt i on of l ocal cor r oded t hi ck ness i n t he ent i r e r egi on of t he dr y wel l pr ov i de addi t i onal st r uct ur al m ar gi n.
- T he Code pr i m ar y st r ess l i m i t s ar e sa t i sf i ed i n t he c or r oded c ondi t i on and t he num ber of f a tig u e c yc le s is s m a ll , th e s u rf a c e d is c o n tin u iti e s f ro m c o rro s io n d o n o t re p re s e n t a si gni f i cant st r uct ur al i nt egr i t y con cer n.
- As i ndi cat ed i n T abl e-1, U T m easu r em ent s of t he dr y wel l she l l abov e t he s and bed r egi on show t hat t he m easu r ed gene r al t hi ck ness con t ai ns s i gni f i cant m ar gi n. C onsi der i ng t he ongoi ng c or r osi on i n t hat r egi on i s i nsi gni f i cant , t he m ar gi n ca n be ap pl i ed t o of f set unce r t ai nt i es r el at ed t o sur f ace r oug hne ss.T a b le 4.7.2 D ry w e ll S h e ll T h ic k n e s s a n d th e M in im u m A v a ila b le T h ic k n e s s M a rg inDr y w ell R egi onNo min al De sig n Thi ckne ss (in ches)Mini mum Measu re d Thi ckne ss, (in ches)Mini mum Re qui re d Thi ckne ss (inc hes)Mini mum A v ail abl e Thi ckne ss Ma rg in (in ches)Cy lindr ical 0.64 0 0.60 4 0.45 2 0.15 2 Knu ckle 2.62 5 2.54 2.29 0.25 Up per S pher e 0.72 2 0.67 6 0.51 8 0.15 8 M iddle S pher e 0.77 0 0.68 2 0.54 1 0.14 1 1 Low er Sph ere 1.15 4 0.80 00.62 9 0.17 1 1 San d B ed 1.15 4 0.80 0 0.73 6 0.06 4 2 1. Th e ge ner al t hi c k nes s i n t he l ower s pher e i s c ons er v at i v el y as s um ed t o be t he s am e as t he s and bed r egi on.2. Th e m i ni m um r equi r ed g ener al t hi c k nes s i n t he s and bed r egi on i s c ont r ol l ed b y buc k l i ng a nal y s i s , gov er ned by l oad c om bi nat i ons t hat do n ot i nc l ude t he 4 4 ps i pr es s ur e.
- U T m easu r em ent s of t he dr y wel l she l l i n t he s and bed r egi on s how t hat t he m easu r ed g e n e ra l th ic k n e s s is g re a te r th a n th e 0.7 3 6'" th ic k n e s s a s s u m e d in th e b u c k li n g a n a ly s is b y s ig n ific a n t m a rg in e x c e p t in 2 b a ys , b a y 1 7 a n d b a y 1 9. (R e f e r to re s p o n s e to R AI 4.7.2-1(d), T abl e-2). T he m ar gi n i n t he gene r al t hi ck ness of t he t wo bay s i s 0.074"and 0.064" r espe ct i v el y. C onsi der i ng t hat si gni f i cant addi t i onal cor r osi on i s no t ex pect ed i n t he s and bed r egi on, t he m ar gi n ca n be ap pl i ed t o of f set unc er t ai nt i es r el at ed t o t he sur f ace r oug hne ss.T he s t af f i dent i f i ed t hi s i ss ue as O I 4.7.2-1.4 i n t he SE R , dat ed August 18, 2006.
4-65 Af t er f ur t her ev al uat i on of t he appl i cant's j ust i f i cat i on, t he s t af f con cl udes t hat use of t he N E-3213.10 pr ov i si ons of Subsec t i on NE of Sect i on I I I of t he AS M E C ode i s ac cept abl e. T he st af f's ac cept ance i s ba sed on t he appl i cant's c onse r v at i v e appr oach es t o i t s de t er m i nat i on of th e a ll o w a b le s h e ll c a p a c ity. S p e c ific a ll y, th e a p p li c a n t d e m o n s tra te d a c c e p ta b le s h e ll c a p a c ity base d on us e of a co nser v at i v e LO C A peak i nt er nal pr ess ur e (i.e., peak i nt er nal pr ess ur e of 62 p s i i n th e e v a lu a tio n v e rs u s th e 4 4 p s i p e a k in te rn a l p re s s u re in a n O ys te r C re e k s p e c ific cal cul at i on appr ov ed by t he NR C i n 1993), use of l ocal cor r oded t hi ck ness f or t he ent i r e r egi on of th e d ryw e ll , a n d c o m p li a n c e w ith lo c a l p rim a ry s tre s s c o d e li m its in th e c o rro d e d c o n d iti o n. In addi t i on, t he appl i cant ex pect s i t s en hanc ed ac t i ons t o pr ev ent addi t i onal cor r osi on i n t he s and bed r egi on. O n t hi s ba si s, t he s t af f's c once r n i s r esol v ed and O pen I t em 4.7.2-1.4 i s c l osed.
4.7.2.2.3 Mi t i gat i ng Act i ons I n R AI 4.7.2-1 dat ed Mar ch 1 0, 2006, t he s t af f r eques t ed t hat t he appl i cant pr ov i de a s um m ar y of t he a ct ual m i t i gat i ng a ct i ons t aken and t hei r ef f ect i v ene ss.I n i t s r espo nse d at ed A pr i l 7, 200 6, t he a ppl i cant l i st ed t he f ol l ow i ng a ct i ons:
- cl ear ed t he f or m er san d bed r egi on dr ai ns t o i m pr ov e dr ai nage,
- r epl aced r eact or cav i t y st eel t r ough dr ai n gas ket , whi ch was f ound t o be l eaki ng,
- re m o v e d w a te r f ro m th e s a n d b e d re g io n ,
- i nst al l ed a c at hodi c pr ot ect i on s y st em i n bay s wi t h gr eat est wal l t hi nni ng i n ear l y 1989 -subs equent U T t hi ck ness m easu r em ent s i n t hese bay s s howed t hat t he s y st em was n ot e f f e c tiv e in re d u c in g th e ra te o f c o rro s io n a n d w a s re m o v e d f ro m s e rv ic e in 1 9 9 2 ,
- re m o v e d s a n d in th e s a n d b e d re g io n to b re a k u p th e g a lv a n ic c e ll ,
- r em ov ed c or r osi on pr oduc t s f r om t he ex t er nal si de of t he s hel l i n t he s and bed r egi on,
- upon s and r em ov al , t he s and bed con cr et e f l oor was f ound c r at er ed and unf i ni shed - t he conc r et e f l oor was r epai r ed, f i ni shed and c oat ed t o per m i t pr oper dr ai nage of t he s and b e d re g io n ,
- appl i ed a s i l i cone sea l at t he j unct ur e of t he dr y wel l she l l and t he s and bed con cr et e f l oor to p re v e n t in tru s io n o f m o is tu re in to th e e m b e d d e d d ryw e ll s h e ll in c o n c re te ,
- a p p li e d a m u lti-la ye re d e p o x y p ro te c tiv e c o a tin g to th e e x te rio r s u rf a c e s o f th e d ryw e ll s h e l l i n th e s a n d b e d re g i o n (i.e., o n e p re-p ri m e r c o a t, a n d tw o to p c o a ts),
- appl i ed s t ai nl ess st eel t y pe t ape and st r i ppabl e co at i ng t o t he r eact or cav i t y dur i ng r ef uel i ng out ages t o se al i dent i f i ed c r ack s i n t he s t ai nl ess st eel l i ner , t hi s l i m i t s wat er i nt r usi on i nt o t he gap bet ween t he dr y wel l she l l and t he dr y wel l shi el d wal l , and conf i r m ed t hat t he r eact or cav i t y con cr et e t r ough dr ai ns a r e not cl ogged T he appl i cant f ur t her ex pl ai ned t hat t hese m i t i gat i ng f eat ur es h av e been i n pl ace si nce 1992.T he m ost ef f ect i v e f eat ur e was t he r em ov al of san d i n t he s and bed r egi on t o br eak up t he gal v ani c c el l , whi ch s i gni f i cant l y r educ ed t he r at e of cor r osi on i n t hat r egi on. T he s and bed r egi on 4-66 coat i ng i s ef f ect i v e bec ause i t i s pr ot ect i ng t he unde r l y i ng dr y wel l she l l f r om ongoi ng c or r osi on, as c onf i r m ed by a co m par i son of U T m easu r em ent s t aken i n 1992, 1994, and 19 96. T he ot her f eat ur es, ex cept f or cat hodi c pr ot ect i on, ar e al so e f f ect i v e bec ause t hei r i m pl em ent at i on l i m i t ed wat er i nt r usi on i nt o t he gap bet ween t he dr y wel l she l l and t he dr y wel l shi el d wal l , t hus r educ i ng th e ra te o f c o rro s io n in th e u p p e r re g io n o f th e d ryw e ll. A com par i son of U T m easu r em ent s t aken i n 1992, 1994, 1996, 2000, and 20 04 on t he uppe r re g io n o f th e d ryw e ll s h e ll s h o w s th a t e ith e r th e c o rro s io n is n o lo n g e r o c c u rrin g o r is n e g li g ib le cons i der i ng t he ac cur acy of U T i nst r um ent s. As st at ed pr ev i ousl y , t he c at hodi c pr ot ect i on s y st em wa s i nst al l ed i n t he b ay s wi t h t he g r eat est wa l l t hi nni ng i n ea r l y 198 9. S ubse que nt U T t hi ckness m easu r em ent s i n t hese bay s s howed t hat t he s y st em was n ot ef f ect i v e i n r educ i ng t he r at e of cor r osi on and was r em ov ed f r om ser v i ce i n 1992.Based on t he di sc uss i on abov e, t he s t af f f i nds t he appl i cant's r espo nse t o i t em (c) acc ept abl e, as it d e s c rib e s th e m iti g a tin g a c tio n s ta k e n b y th e a p p li c a n t. T h e s ta f f's c o n c e rn d e s c rib e d in R AI 4.7.2-1(c) i s r esol v ed.
4.7.2.2.4 C har t of U l t r ason i c T est M easu r em ent s I n R AI 4.7.2-1 dat ed Mar ch 1 0, 2006, t he s t af f r eques t ed t hat t he appl i cant pr ov i de a c o m p a ra tiv e g ra p h (o r c h a rt) s h o w in g th e d ryw e ll th ic k n e s s b a s e d o n th e a s s u m e d c o rro s io n ra te and t hat act ual l y f ound af t er t he m i t i gat i ng ac t i ons wer e i m pl em ent ed.I n i t s r espo nse dat ed Apr i l 7, 2006, t he appl i cant pr ov i ded Tabl es 1 and 2. T hese t abl es p r ov i de U T t hi ck ness m easu r em ent s f or t he uppe r r egi on of t he dr y wel l , and f or t he s and bed r egi on of th e d r yw e ll s h e ll, r e s p e c tiv e ly.T h e s ta f f f in d s th e ta b le s a n d f ig u re s u s e f u l i n u n d e rs ta n d in g th e e x te n t o f c o rro s io n. T h e s ta f f's conc er n des cr i bed i n R AI 4.7.2-1(d) i s r esol v ed.
4.7.2.2.5 Loc at i on of D r y wel l C or r osi on J u n c tio n o f D ryw e ll F lo o r a n d S h e ll I n R A I 4.7.2-2 d a t e d M a r c h 1 0 , 2 0 0 6 , t h e s t a ff n o t e d t h a t a n u m b e r o f M a r k I c o n t a i n m e n t s h a ve ex per i ence d co r r osi on i nsi de t hei r dr y wel l s at t he j unct i on of t he bot t om con cr et e f l oor and t he st eel she l l. T he s t af f r eques t ed t hat t he appl i cant pr ov i de i nf or m at i on r egar di ng c or r osi on of t he dr y we l l shel l at t hi s l ocat i on o r any ot her l ocat i on o f t he d r y we l l i nsi de su r f aces.I n i t s r espo nse dat ed Apr i l 16, 2006, t he appl i cant st at ed t hat O C G S has not ex per i ence d c o rro s io n o n th e in s id e s u rf a c e s o f th e d ryw e ll s h e ll , in c lu d in g th e ju n c tio n o f th e b o tto m c o n c re te f l oor and t he s t eel she l l. T he i nsi de of t he dr y wel l i s c oat ed wi t h C ar bo-Zi nk 1 1 ov er an SS PC-SP 6/SP 5, com m er ci al abr asi v e bl ast sur f ace pr epar at i on t o a dr y f i l m t hi ck ness of 3-6 m il s. M o re o v e r, v is u a l i n s p e c tio n s c o n d u c te d in a c c o rd a n c e w ith A S M E C o d e S e c tio n X l, S u b s e c tio n IW E , h a v e n o t id e n tifie d re c o rd a b le c o rro s io n a t th e ju n c tio n o f th e b o tto m c o n c re te f l oor and t he s t eel she l l or any ot her l ocat i on i nsi de t he dr y wel l. Mi nor sur f ace r ust has been not ed i n so m e ar eas wher e t he c oat i ng i s da m aged or r em ov ed f or U T m easu r em ent s. T he m i nor sur f ace r ust i s l i m i t ed t o i sol at ed ar eas and doe s no t i m pact t he i nt ended f unct i on of t he d ryw e ll.
4-67 B a s e d o n th e a b o v e d is c u s s io n , th e s ta f f f in d s th is re s p o n s e a c c e p ta b le , a s th e c o n d iti o n w o u ld n o t c h a ll e n g e th e in te n d e d f u n c tio n o f th e d ryw e ll s h e ll. T h e s ta f f's c o n c e rn d e s c rib e d in R A I 4.7.2-2 is re s o lv e d.
O pen I t em 4.7.2-3: Leak age Fr om R ef uel i ng Seal I n R AI 4.7.2-3 dat ed Mar ch 1 0, 2006, t he s t af f not ed t hat l eaka ge f r om t he r ef uel i ng s eal has been i dent i f i ed as one of t he r easo ns f or acc um ul at i on of wat er and c ont am i nat i on of t he sand-pock et ar ea. T he r ef uel i ng wat er pas ses t hr ough t he gap bet ween t he s hi el d co ncr et e and th e d ryw e ll s h e ll in th e lo n g le n g th o f in a c c e s s ib le a re a s. A s th e re is a p o te n tia l fo r c o rro s io n in t hi s ar ea, AS M E C ode Subsec t i on I W E woul d r equi r e augm ent ed i nspe ct i on of t hi s ar ea. T he st af f r eques t ed t hat t he appl i cant pr ov i de a s um m ar y of i nspe ct i ons per f or m ed (v i sual and nondes t r uct i v e ex am i nat i on (N D E)) and m i t i gat i ng ac t i ons t aken t o pr ev ent wat er l eaks f r om t he r ef uel i ng se al com pon ent s.I n i t s r e s p o n s e d a t e d A p r i l 1 6 , 2 0 0 6 , t h e a p p l i c a n t s t a t e d t h a t t h e r e f u e l i n g s e a l s a t OCGS cons i st of st ai nl ess st eel bel l ows. I n t he m i d-t o-l at e 1980s , G PU con duct ed ex t ensi v e v i sual and N D E i nspe ct i ons t o det er m i ne t he s our ce o f wat er i nt r usi on i nt o t he s ei sm i c ga p bet ween t he dr y wel l con cr et e sh i el d wal l and t he dr y wel l she l l and i t s ac cum ul at i on i n t he s and bed r egi on.T he i nspe ct i ons conc l uded t hat t he r ef uel i ng bel l ows (seal s) wer e not t he s our ce o f wat er l eaka ge. T he bel l ows wer e r epeat edl y t est ed us i ng hel i um (ex t er nal) and ai r (i nt er nal) wi t hout any i ndi cat i on of l eaka ge. Fur t her m or e, any m i nor l eaka ge f r om t he r ef uel i ng bel l ows wou l d be c o ll e c te d in a c o n c re te tro u g h b e lo w th e b e ll o w s. T h e c o n c re te tro u g h is e q u ip p e d w ith a d ra in l i ne t hat woul d di r ect any l eaka ge t o t he r eact or bui l di ng equi pm ent dr ai n t ank and pr ev ent i t f r om e n te ri n g th e s e i s m i c g a p. T h e d ra i n l i n e h a s b e e n c h e c k e d b e fo re re fu e l i n g o u ta g e s to c o n firm th a t it i s n o t b lo c k e d. T h e o n ly o th e r s e a l i s th e g a s k e t fo r th e re a c to r c a v ity s te e l tro u g h d ra in l i ne. T hi s ga sk et was r epl aced af t er t he t est s s howed t hat i t was l eaki ng. H owev er , t he gas ket l e a k w a s ru l e d o u t a s th e p ri m a ry s o u rc e o f w a te r o b s e rv e d i n th e s a n d b e d d ra i n s b e c a u s e th e re i s no cl ear l eaka ge pat h t o t he s ei sm i c ga p. Mi nor gas ket l eaks woul d be c ol l ect ed i n t he conc r et e t r ough be l ow t he gas ket and woul d be r em ov ed by t he dr ai n l i ne s i m i l ar t o l eaks f r om t he r ef uel i ng b el l ow s.I n addi t i on, t he appl i cant not ed t hat addi t i onal v i sual and ND E (dy e penet r ant) i nspe ct i ons on t he r eact or cavi t y st ai nl ess st eel l i ner had i den t i f i ed a si gni f i cant num ber of cr acks, som e of wh i ch w e re th ro u g h w a ll c ra c k s. E n g in e e rin g a n a ly s is c o n c lu d e d th a t th e c ra c k s w e re m o s t p ro b a b ly caus ed by m echa ni cal i m pact or t her m al f at i gue, and no t I G SC C. T hese cr ack s wer e det er m i ned t o be t he s our ce o f r ef uel i ng wat er t hat pas sed t hr ough t he s ei sm i c ga p. T o pr ev ent l eaka ge t hr ough t he c r ack s, G PU i nst al l ed an a dhes i v e-t y pe s t ai nl ess st eel t ape t o br i dge any obs er v ed l ar ge c r ack s an d su bseq uent l y appl i ed a s t r i ppabl e co at i ng. T hi s r epai r gr eat l y r educ ed l eaka ge and was i m pl em ent ed ev er y r ef uel i ng out age whi l e t he r eact or cav i t y was f l ooded.T he appl i cant not ed t hat i t has com m i t t ed t o m oni t or t he s and bed r egi on dr ai ns f or wat er l eaka ge. A r ev i ew of pl ant doc um ent at i on di d not pr ov i de obj ect i v e ev i denc e t hat t he c o m m itm e n t h a s b e e n im p le m e n te d s in c e 1 9 9 8. Is s u e R e p o rt N o. 3 4 8 5 4 5 w a s is s u e d in acc or danc e wi t h t he O G C S cor r ect i v e ac t i on pr oces s t o doc um ent t he l apse i n i m pl em ent i ng t he com m i t m ent and t o r ei nf or ce s t r i ct com pl i ance wi t h co m m i t m ent i m pl em ent at i on i n t he f ut ur e, i ncl udi ng dur i ng t he per i od of ex t ended o per at i on.T he appl i cant al so c om m i t t ed (C om m i t m ent N o. 27, I t em 4) t o per f or m i ng augm ent ed i nspe ct i ons of t he dr y wel l i n ac cor danc e wi t h AS M E C ode Sect i on Xl , Subsec t i on I W E. T hese i nspe ct i ons cons i st of U T ex am i nat i ons of t he uppe r r egi on of t he dr y wel l and v i sual ex am i nat i ons of t he 4-68 p ro te c tiv e c o a tin g o n th e e x te rio r o f th e d ryw e ll s h e ll in th e s a n d b e d re g io n. U T m e a s u re m e n ts wi l l supp l em ent t he vi sual i nspe ct i on o f t he co at i ng m easu r em ent s f r om i nsi de t he d r y we l l once bef or e ent er i ng t he per i od of oper at i on and ev er y 10 y ear s t her eaf t er dur i ng t he per i od of e x te n d e d o p e ra tio n. T he s t af f's r ev i ew of t he appl i cant's r espo nse det er m i ned t hat t he epox y coa t i ng appl i ed i n t he sand-bed r egi on of t he s hel l has a l i m i t ed l i f e and wat er l eaka ge f r om t he ai r gap ha s no t been pr ev ent ed. I n v i ew of t hese obs er v at i ons, t he s t af f r eques t ed t hat t he appl i cant pr ov i de a sy st em at i c pr ogr am of ex am i nat i on of t he c oat i ng t hat woul d pr ov i de c onf i denc e t hat t he p re v e n tiv e m e a s u re is a d e q u a te ly im p le m e n te d a t a ll lo c a tio n s in th e s a n d-p o c k e t a re a s. I n i t s r espo nse dat ed J une 20, 2006, t he appl i cant com m i t t ed t hat i t wi l l m oni t or t he s and bed re g io n d ra in s o n a d a il y b a s is d u rin g re f u e li n g o u ta g e s a n d ta k e th e f o ll o w in g a c tio n s if w a te r is det ect ed. T he ac t i ons wi l l be c om pl et ed pr i or t o ex i t i ng t he out age.
- T he s our ce o f wat er wi l l be i nv est i gat ed and di v er t ed, i f pos si bl e, f r om ent er i ng t he gap b e tw e e n th e d ryw e ll s h e ll a n d th e d ryw e ll s h ie ld w a ll.
- T he wat er wi l l be c hem i cal l y anal y z ed t o ai d i n det er m i ni ng t he s our ce o f l eaka ge.
- A r em ot e i nspe ct i on wi l l be per f or m ed i n t he t r ough dr ai n ar ea t o det er m i ne i f t he t r ough d r a in s a r e o p e r a tin g p r o p e r ly.
- T he c ondi t i on of t he c oat i ng and t he m oi st ur e bar r i er (seal) i n t he af f ect ed bay s wi l l be i nspe ct ed.
- I f t he c oat i ng i s de gr aded an d v i sual i nspe ct i on i ndi cat es c or r osi on i s t aki ng pl ace, t hen U T t hi ck ness m easu r em ent s wi l l be t aken i n t he af f ect ed ar eas of t he s and bed r egi on.T he m easu r em ent s wi l l be t aken f r om ei t her i nsi de or out si de t he dr y wel l t o ens ur e t hat t he sh el l t hi ckness i n ar eas a f f ect ed b y wa t er l eaka ge i s m easu r ed. U T t hi ckness me a s u r e me n t s a n d e v a l u a t i o n w i l l b e c o n s i s t e n t w i t h t h e e x i s t i n g p r o g r a m.
- T he degr aded c oat i ng and/or t he s eal wi l l be r epai r ed i n ac cor danc e wi t h st at i on pr oced ur es.
- U T m easu r em ent s wi l l be t aken i n t he uppe r r egi on of t he dr y wel l con si st ent wi t h t he e x i s t i n g p r o g r a m.T he appl i cant , al so, com m i t t ed (C om m i t m ent N o. 27, I t em 3) t o m oni t or t he s and bed r egi on dr ai ns q uar t er l y dur i ng t he oper at i ng c y cl e. T he appl i cant st at ed t hat i f wat er i s de t ect ed, act i ons l i st ed bel ow wi l l be t aken. T hose t hat r equi r e an ou t age t o be ac com pl i shed wi l l be c om pl et ed dur i ng t he nex t sc hedul ed r ef uel i ng out age.
- T he l eaka ge r at e wi l l be qua nt i f i ed t o det er m i ne a r epr esen t at i v e f l ow r at e. T he l eaka ge r at e wi l l be t r ended.
- T he s our ce o f wat er wi l l be i nv est i gat ed and di v er t ed, i f pos si bl e, f r om ent er i ng t he gap b e tw e e n th e d ryw e ll s h e ll a n d th e d ryw e ll s h ie ld w a ll.
- T he wat er wi l l be c hem i cal l y anal y z ed t o ai d i n det er m i ni ng t he s our ce o f l eaka ge.
- T he c ondi t i on of t he c oat i ng and t he m oi st ur e bar r i er (seal) i n t he af f ect ed bay s wi l l be in s p e c te d d u r in g th e n e x t r e f u e lin g o u ta g e o r a n o u ta g e o f o p p o r tu n ity.
- I f t he c oat i ng i s de gr aded an d v i sual i nspe ct i on i ndi cat es c or r osi on i s t aki ng pl ace, t hen U T t hi ck ness m easu r em ent s wi l l be t aken i n t he af f ect ed ar eas of t he s and bed r egi on.
4-69 T he m easu r em ent s wi l l be t aken f r om ei t her i nsi de or out si de t he dr y wel l t o ens ur e t hat t he sh el l t hi ckness i n ar eas a f f ect ed b y wa t er l eaka ge i s m easu r ed. U T t hi ckness me a s u r e me n t s a n d e v a l u a t i o n o f t h e r e s u l t s w i l l b e c o n s i s t e n t w i t h t h e e x i s t i n g p r o g r a m.
- U T m easu r em ent s wi l l be t aken i n t he uppe r r egi on of t he dr y wel l con si st ent wi t h t he e x i s t i n g p r o g r a m.
- T he degr aded c oat i ng and/or t he s eal wi l l be r epai r ed i n ac cor danc e wi t h st at i on p ro c e d u re s. T he s t af f f i nds t hat t he appl i cant's pr ogr am wi l l pr ov i de r easo nabl e as sur ance t hat any f ur t her i nci dent s of wat er i n t he s and bed r egi on wi l l be s y st em at i cal l y ev al uat ed, and ac t i ons wi l l be t aken t o pr ev ent f ur t her degr adat i on of t he dr y wel l she l l. H owev er , t he pr ogr am was n ot cl ear r egar di ng t he ex t ent of t he c oat ed s ur f aces ex am i ned dur i ng eac h i nspe ct i on. T hi s was i dent i f i ed as OI 4.7.2-3 i n t he SE R , dat ed August 18, 2006.T h e a p p li c a n t c o m m itte d (C o m m itm e n t N o. 2 7) to m o n ito rin g o f th e c o a tin g o n th e d ryw e ll s h e ll ex t er i or i n t he s and bed r egi on as par t of i t s ASM E S ect i on XI , Subsec t i on I W E P r ogr am and of its P ro te c tiv e C o a tin g M o n ito rin g a n d M a in te n a n c e P ro g ra m. T h e a p p li c a n t c o m m itte d to addi t i onal v i sual i nspe ct i ons of t he epox y coa t i ng i n al l 10 dr y wel l bay s at l east onc e pr i or t o t he per i od of ex t ended o per at i on. I n a l et t er dat ed Decem ber 3, 2006, t he appl i cant st at ed t hat 100 per cent of t he epox y coa t i ng had been i nspe ct ed dur i ng t he O ct ober 2006 o ut age wi t h no evi den ce of f l aki ng, bl i st er i ng, pee l i ng, di scol or at i on o r ot her si gns o f coat i ng d i st r ess. T hese com m i t m ent s, wi t h t he I W E pr ogr am and t he O ct ober 2006 i nspe ct i on whi ch i ndi cat ed no c oat i ng degr adat i on, r esol v e t he s t af f con cer n ov er t he ex t ent of coa t i ngs i nspe ct i on. T her ef or e, t he st af f's c once r n i s r esol v ed and O pen I t em 4.7.2-3 i s c l osed.I n i t s l et t er dat ed Febr uar y 15, 2007, t he appl i cant r ev i sed a co m m i t m ent (C om m i t m ent N o. 27)by addi ng I t em 19, whi ch s t at es t hat Am er G en wi l l per f or m an eng i neer i ng s t udy pr i or t o t he p ro p o s e d re n e w a l p e rio d to in v e s tig a te c o s t-e f f e c tiv e re p la c e m e n t o r re p a ir o p tio n s to e li m in a te o r re d u c e re a c to r c a v ity li n e r le a k a g e. T h e A C R S re c o m m e n d e d th e li c e n s e b e c o n d iti o n e d to re q u ire th e s tu d y. T h e s ta f f id e n tifie d th is a s a li c e n s e c o n d iti o n c o n s is te n t w ith th e a p p li c a n t's C om m i t m ent 27 i t em 19.
4.7.2.2.6 U l t r ason i c Test Measur em ent Pr ogr am I n v i ew of t he unc er t ai nt y r egar di ng t he l ong-t er m ef f ect i v enes s of t he c oat i ng and wat er l eaka ge, t he st af f r equ est ed t hat t he a ppl i cant r evi ew t he a ccur acy of t he U T m easu r em ent s and est abl i sh a cr edi bl e pr ogr am f or per f or m i ng t he UT ex am i nat i on of t he s hel l i n t he s and-bed r egi on dur i ng th e p e rio d o f e x te n d e d o p e ra tio n. In its re s p o n s e d a te d J u n e 2 0 , 2 0 0 6 , th e a p p li c a n t s ta te d: In a le tte r d a te d A p ril 4 , 2 0 0 6 , A m e rG e n c o m m itte d to p e rf o rm U T m e a s u re m e n ts of t he s and bed r egi on ev er y 10 y ear s. I n v i ew of t he unc er t ai nt y r egar di ng t he l ong-t er m ef f ect i v enes s of t he c oat i ng and wat er l eaka ge, t he NR C r eques t ed t he appl i cant t o cl ar i f y t he c om m i t m ent f or U T m easu r em ent f r equenc y i n t he s and bed r egi on.A m e rG e n is c o n f id e n t th a t th e a g in g m a n a g e m e n t p ro g ra m it c o m m itte d its e lf to in th e A p ril 4 , 2 0 0 6 le tte r is a d e q u a te to e n s u re th a t s ig n ific a n t d ryw e ll c o rro s io n w il l be det ect ed and addr ess ed pr i or t o i m pact i ng t he i nt ended f unct i on of t he 4-70 cont ai nm ent. T he pr ogr am r equi r es v i sual i nspe ct i on of t he c oat i ng i n t he s and bed r egi on on a f r equenc y of ev er y ot her r ef uel i ng out age.T he pr ogr am al so r equi r es p er f or m i ng UT i nspe ct i ons i n t he uppe r r egi ons of t he d ryw e ll s h e ll o n a f re q u e n c y o f e v e ry o th e r re f u e li n g o u ta g e. T h e m e a s u re m e n ts i n t he uppe r r egi on of t he dr y wel l bound t he s and bed r egi on s i nce t he env i r onm ent i s t he s am e and t he s and bed r egi on i s pr ot ect ed wi t h epox y coa t i ng w h il e th e u p p e r re g io n is c o a te d o n ly w ith a Z in c p rim e r. In a d d iti o n , A m e rG e n is com m i t t ed t o pe r f or m i ng U T exam i nat i ons o f t he sa nd b ed r egi on e v er y 10 y ear s.T he 10-y ear f r equenc y f or t he UT m easu r em ent s i s ba sed on AS M E S ect i on XI re q u ire m e n ts a n d is in te n d e d to c o n f irm th a t th e c o a tin g c o n tin u e s to m iti g a te cor r osi on. T he i ni t i al U T m easu r em ent s wi l l be t aken pr i or t o ent er i ng t he per i od of ex t ended o per at i on. T he UT m easu r em ent s ar e onl y a par t of t he ov er al l pr ogr am desi gned t o pr ov i de r easo nabl e as sur ance t hat si gni f i cant cor r osi on i s de t ect ed bef or e co nt ai nm ent i nt ended f unct i on i s ad v er sel y i m pact ed.N ev er t hel ess , Am er G en wi l l t ake a se cond set of U T m easu r em ent s i n t he s and bed r egi on t wo r ef uel i ng out ages af t er t he m easu r em ent s t aken pr i or t o ent er i ng t he per i od of ex t ended o per at i on. T he r esul t s of t he m easu r em ent s wi l l bee v a lu a te d to d e te rm in e th e a p p ro p ria te m e a s u re m e n t fr e q u e n c y re q u ire d to p ro v id e c o n tin u e d re a s o n a b le a s s u ra n c e th a t c o rro s io n is b e in g e f f e c tiv e ly m oni t or ed a nd m ana ged dur i ng t he p er i od o f ext end ed o per at i on. T he f r equ ency wi l l be es t abl i shed as a ppr opr i at e, but not t o ex ceed ev er y 10 y ear s. I n I t em H of t he J une 20, 2006 r espo nse, Am er G en pr ov i des addi t i onal i nf or m at i on on t he act i ons t hat wi l l be t aken i f wa t er i s det ect ed i n t he sa nd b ed r egi on d r ai ns.Based on t he appl i cant's c om m i t m ent (C om m i t m ent N o. 27), t he s t af f under st ands t hat t he appl i cant wi l l t ake U T m easu r em ent s i n t he s and bed r egi on t wo r ef uel i ng out ages af t er t he m e a s u re m e n ts ta k e n p rio r to e n te rin g th e p e rio d o f e x te n d e d o p e ra tio n. T h e s ta f f's f in d s th is a c c e p ta b le; th e re f o re , th e c o n c e rn is re s o lv e d. I n R A I 4.7.2-4 da t ed M ar ch 10 , 200 6, t he st af f not ed t hat i ndu st r y wi de o per at i ng e x per i ence i n d i c a t e s a n u mb e r o f i n c i d e n c e s o f t o r u s c o r r o s i o n i n Ma r k I c o n t a i n me n t s. Ne i t h e r L RA T abl e 3.5.2.1.1 nor t he AS M E S ect i on XI , Subsec t i on I W E P r ogr am des cr i bes oper at i ng ex per i ence r el at ed t o co r r osi on of t he O C G S t or us. T he s t af f r eques t ed t hat t he appl i cant pr ov i de a s um m ar y of t he r esul t s of I W E i nspe ct i ons per f or m ed on t he t or us a nd i nst ance s of to ru s c o rro s io n. I n SE R Sect i on 3, t he s t af f ev al uat es t he c ondi t i on of t he t or us (supp r ess i on c ham ber) and conc l udes t hat agi ng ef f ect s wi l l be ade quat el y m anaged dur i ng t he per i od of ex t ended o p e ra tio n.
4.7.2.2.7 S and i a N at i ona l Lab or at or i es D r y we l l S t r uct ur al A nal y si s T o p ro v id e a d d iti o n a l a s s u ra n c e th a t th e a p p li c a n t's A M P (a s d is c u s s e d in S e c tio n 3), w o u ld pr ov i de a f r am ewor k f or i nsur i ng t hat t he O y st er C r eek dr y wel l she l l can wi t hst and t he pos t ul at ed desi gn l oads dur i ng t he r enewal per i od, t he NR C st af f con t r act ed wi t h Sandi a N at i onal Labor at or i es (Sandi a) t o anal y z e t he dr y wel l wi t h co nser v at i v el y bi ased m odel i ng of t he degr adat i on. T he Sandi a anal y si s i s i n r epor t SA N D 2007-0055 (M L07012 0395), "St r uct ur al I nt egr i t y Anal y si s of t he Degr aded Dr y wel l C ont ai nm ent at t he O y st er C r eek N ucl ear G ener at i ng St at i on," whi ch was i ss ued on Janu ar y 12, 2007. As par t of t he anal y si s, Sandi a dev el oped a 4-71 det ai l ed t hr ee-di m ensi onal (3D) f i ni t e el em ent m odel of t he dr y wel l con t ai nm ent v ess el usi ng i nf or m at i on pr ov i ded by t he NR C and t he appl i cant. T he m odel was u sed t o ev al uat e t he st r uct ur al i nt egr i t y of t he v ess el i n t er m s of t he s t r ess l i m i t s s peci f i ed i n t he AS M E B oi l er and Pr ess ur e Vesse l (B&PV) C ode, Sect i on I I I , D i v i si on I , Subsec t i on NE , and i n t er m s of buc kl i ng (s ta b il ity) lim its s p e c ifie d in A S M E B&P V C o d e C a s e N-2 8 4. T h e p u rp o s e o f th e S a n d ia a n a ly s is was t o ex am i ne whet her t he O y st er C r eek degr aded dr y wel l she l l can wi t hst and t he pos t ul at ed lo a d in g s w ith o u t e x c e e d in g th e A S M E c o d e re q u ir e m e n ts f o r s tr e s s a n d s ta b ility.T he Sandi a anal y si s di d not r epl ace or r epr oduc e t he anal y si s do ne i n t he G E st udy. T he base l i ne (i.e. un-degr aded) anal y si s was per f or m ed t o i sol at e t he ef f ect s of t he degr adat i on. T he Sandi a anal y si s f ocus ed m or e on t he r el at i v e r educ t i on i n des i gn m ar gi n due t o t he c or r osi on t han on t he ca l cul at ed a bsol ut e st r esses o r st abi l i t y l i m i t s.T he Sandi a anal y si s us ed a di f f er ent m odel i ng appr oach t han t he G E st udy and m ade ass um pt i ons r egar di ng gene r al des i gn i nf or m at i on when p l ant spe ci f i c i nf or m at i on was una v ai l abl e. A nal y st j udg m ent wa s used i n ap pl y i ng t he A S M E C ode r equ i r em ent s.C o n s e q u e n tl y , t h e n u m e ri c a l v a l u e s d e ri v e d b y th e S a n d i a a n a l y s i s a re g e n e ri c i n n a tu re a n d a re not par t of t he O y st er C r eek cu r r ent l i censi ng b asi s.T he Sandi a st udy i ncl uded s t r ess and bu ck l i ng anal y ses f or bot h a r epr esen t at i on of t he cont ai nm ent i n i t s deg r ade d con di t i on a nd i n i t s or i gi nal , as-bui l t , cond i t i on. T he st udy of t he a s-bui l t con di t i ons pr ov i des base-l i ne anal y ses t o as ses s t he ef f ect s of degr adat i on on t he s t r ess es a n d b u c k li n g b e h a v io r f o r th e c o n ta in m e n t. T he c oncl usi ons r esul t i ng f r om t he s t udy i ncl uded:
- T h e in tro d u c tio n o f d e g ra d a tio n d o e s c a u s e a n o tic e a b le in c re a s e in th e s tre s s le v e ls th ro u g h o u t th e d ryw e ll s h e ll f o r e a c h lo a d c o n d iti o n.
- I n gener al , t he ac ci dent con di t i on (acc i dent pr ess ur e 44 ps i g, and t em per at ur e 292 E F)c a u s e s th e la rg e s t s tre s s in c re a s e s th ro u g h o u t th e d ryw e ll w h e n d e g ra d a tio n is i nt r oduc ed.
- T he buc kl i ng ev al uat i on per f or m ed us i ng AS M E N-284 s how t hat bas ed on t he l oadi ngs and t he Sandi a m odel , bot h t he r ef uel i ng and post-acc i dent l oad c om bi nat i ons m et buckl i ng r equ i r em ent s.
- AS M E al l owabl e st r ess es a r e m et f or al l t hr ee l oad c ases ex am i ned.T he ef f ect s of l ocal l y t hi nner r egi ons i n bay s #1 and #1 3 wer e ex pl or ed. U nder t he r ef uel i ng l oad cond i t i on, t he buc kl i ng i ni t i at i on was obs er v ed as a r esul t of t hese t hi n ar eas. H owev er , t he ef f ect i v e sa f et y f act or was m ai nt ai ned abo v e t he AS M E m i ni m um of 2.0 f or t he l oad c om bi nat i on cont ai ni ng l oadi ngs f r om t he r ef uel i ng ac t i v i t i es, t he pos t ul at ed s ei sm i c l oads , and a h y pot het i cal ex t er nal pr ess ur e l oad of 2 poun ds p er squ ar e i nch.T h e S a n d ia R e p o rt re s u lts s u p p o rt a n d c o n f irm th a t th e d ryw e ll w il l b e a b le to p e rf o rm its in te n d e d f u n c tio n s in its p re s e n t c o n d iti o n. T h e re p o rt a ls o in d ic a te s th a t th e a re a s o f th e d ryw e ll shel l abov e and b el ow t he s and bed r egi on hav e su f f i ci ent t hi ck ness t o ac com m odat e addi t i onal c o rro s i o n o f th e s h e l l b e fo re A S M E C o d e s a fe ty fa c to rs o r m i n i m u m w a l l th i c k n e s s c ri te ri a a re r each ed. H owev er , i n t he s and bed r egi on, U T m easu r em ent s i ndi cat e t hat wal l t hi ck ness of 4-72 som e ar eas of t he s hel l ar e at or near t he wal l t hi ck ness r equi r ed t o sa t i sf y t he AS M E C ode saf et y f act or or t he m i ni m um wal l t hi ck ness cr i t er i a.Addi t i onal l y , t he NR C st af f r eques t ed Sandi a t o per f or m an ana l y si s of t he dr y wel l she l l wi t h t he e x is tin g d e g ra d a tio n to a s s e s s th e m in im u m th ic k n e s s re q u ire d in th e s a n d b e d a re a to m a in ta in t he m i ni m um saf et y f act or s ag ai nst buc ki ng. Sandi a anal y z ed t he s hel l usi ng t he pr ov i si ons of A S M E S e c tio n III C o d e C a s e N-2 8 4. In c o n s id e rin g th e c a p a c ity re d u c tio n f a c to r a p p li c a b le to t h e l o a d c o m b i n a t i o n i n c o r p o r a t i n g t h e r e fue l i n g l o a d a n d e xt e r n a l p r e s s u r e , S a n d i a d i d n o t g i ve a n y c r e d i t t o t h e m e m b r a n e t e n s i l e s t r e s s e s p r o d u c e d i n t h e s h e l l b y t h e m e r i d i o n a l c o m p r e s s i ve l oad, by not i ncr easi ng c apac i t y r educ t i on f act or. Sandi a ar r i v ed at a m i ni m um t hi ck ness of 0.8 4 4".I n t he s t af f's SER dat ed Apr i l 14, 1992, t he s t af f had m ade an ass ess m ent of t he G E anal y si s f or t he l oad c om bi nat i on i ncor por at i ng t he r ef uel i ng l oad and ex t er nal pr ess ur e. T he SE R and a tta c h e d T e c h n ic a l E v a lu a tio n R e p o rt b y B ro o k h a v e n N a tio n a l L a b o ra to ry d o c u m e n te d th e s ta f f's r ev i ew of t he i ncr ease d ca paci t y r educ t i on f act or due t o t he m em br ane t ensi on, and ac cept ed t he p ro c e s s o f d e ri v i n g th e i n c re a s e d c a p a c i ty re d u c ti o n fa c to r. T h e G E a n a l y s i s a s s u m e d a u n i fo rm m i ni m um t hi ck ness i n t he s and bed r egi on of 0.736". T he St af f f i nds t he us e of t he i ncr ease d c a p a c i t y r e d u c t i o n f a c t o r d e s c r i b e d i n t h e GE a n a l y s i s i s r e a s o n a b l e a n d c o n s i s t e n t w i t h ASM E C ode Case N-284 as wel l as ASM E S ect i on VI I I , C ode Case 2286
.Based on i t s r ev i ew and t he appl i cant's Com m i t m ent 27, t he s t af f i dent i f i ed a l i cens i ng c ondi t i on t hat r equi r es t he appl i cant t o m oni t or t he s hel l degr adat i on i n al l 10 bay s of t he s and bed r egi on ev er y ot her r ef uel i ng out age t hr oughou t t he r enewal per i od.D ur i ng t he Adv i sor y C om m i t t ee on React or Saf eguar ds (AC R S) m eet i ng on Febr uar y 1, 2007, th e a p p li c a n t c o m m itte d to p e rf o rm a 3-D (d im e n s io n a l) fin ite-e le m e n t a n a ly s is o f th e d ryw e ll shel l pr i or t o ent er i ng t he per i od of ex t ended o per at i ons. I n i t s l et t er dat ed Febr uar y 15, 2007, t he app l i cant r evi sed a l i cense com m i t m ent (C om m i t m ent N o. 27) by add i ng S ub-i t em 18, wh i ch st at es t hat Am er G en wi l l per f or m a 3-D f i ni t e el em ent al anal y si s of t he pr i m ar y con t ai nm ent d r yw e ll s h e ll u s in g m o d e r n m e th o d s a n d c u r r e n t d r yw e ll s h e ll th ic k n e s s d a ta to b e tt e r q u a n tif y th e m a rg in th a t e x is ts a b o v e th e C o d e re q u ire m e n t fo r b u c k li n g. T h e s ta f f id e n tifie d th is com m i t m ent i t em as a l i cens e co ndi t i on.
4.7.2.3 UFSAR Suppl em en t T he appl i cant pr ov i ded a UFS AR sup pl em ent sum m ar y des cr i pt i on of i t s TLA A ev al uat i on of dr y wel l cor r osi on i n LRA Sect i on A.4.5.2.T he s t af f's r ev i ew of LR A S ect i on A.4.5.2 i dent i f i ed an a r ea i n whi ch a ddi t i onal i nf or m at i on was n e c e s s a ry to c o m p le te th e re v ie w o f d ryw e ll c o rro s io n. I n RAI 4.7.2-5 d a t e d Ma r c h 1 0 , 2 0 0 6 , t h e s t a f f n o t e d t h a t f o r t h i s i m p o r t a n t i s s u e t h e UFS AR s u p p le m e n t s h o u ld , a t a m in im u m , b rie f ly d e s c rib e th e q u a n tita tiv e a s p e c t o f th e d ryw e ll cor r osi on and t he appl i cant's as ser t i ons t o m ai nt ai n i t abov e a c er t ai n t hi ck ness t o ens ur e t hat t he c ont ai nm ent can per f or m i t s i nt ended f unct i on dur i ng t he per i od of ex t ended o per at i on. T he appl i cant wi l l use t he T LAA and Subse ct i on I W E of t he AS M E C ode t o m ai nt ai n t he c ont ai nm ent f u n c tio n a li ty. I n i t s r espo nse dat ed Apr i l 26, 2006, t he appl i cant st at ed t hat U FS AR Sect i on 3.8.2.8 pr ov i des hi st or i cal i nf or m at i on on d r y wel l cor r osi on and cor r ect i v e ac t i ons t aken t o co nt r ol i t. T he s ect i on 4-73 a l s o d e s c ri b e s a g i n g m a n a g e m e n t a c ti v i ti e s th a t a re i m p l e m e n te d d u ri n g th e c u rre n t t e rm cons i st ent wi t h t he ex i st i ng c om m i t m ent s t o N R C. T he s ect i on i s r ev i sed per i odi cal l y t o i ncl ude, by r ef er ence , t he r esul t s of quant i t at i v e engi neer i ng anal y ses , t he UT m easu r em ent s i n t he upper r egi ons of t he dr y wel l , and i nspe ct i on of t he c oat i ng of t he dr y wel l she l l i n t he s and bed r egi on.T he appl i cant st at ed t hat LR A S ect i on A.1.27, AS M E C ode Sect i on XI , Subsec t i on I W E, and t he li c e n s e re n e w a l c o m m itm e n t li s t (C o m m itm e n t N o. 2 7), w h ic h a re in c lu d e d in th e a p p li c a tio n , w il l be i ncor por at ed i n t he UF SA R as a sup pl em ent. H owev er , t he appl i cant r ecog ni z es t hat bot h t he L R A A p p e n d i x A a n d t h e c o m m i t m e n t l i s t d o n o t i n c l u d e a d d i t i o n a l c o m m i t m e n t s t o t h e N R C s t a ff o n d ryw e ll c o rro s io n f o r th e p e rio d o f e x te n d e d o p e ra tio n. H e n c e , th e a p p li c a n t s ta te d th a t it w il l r ev i se t he c om m i t m ent l i st t o i ncl ude det ai l s of t hese addi t i onal com m i t m ent s an d wi l l use i t as t he bas i s f or t he dr y wel l cor r osi on agi ng m anagem ent pr ogr am dur i ng t he per i od of ex t ended oper at i on. T he r ev i sed com m i t m ent l i st and LRA Sect i on A.1.27 wi l l be i ncor por at ed i n t he U FS AR. T he s uppl em ent , t her ef or e, wi l l i ncl ude el em ent s of t he dr y wel l cor r osi on agi ng m anagem ent pr ogr am i n su f f i ci ent det ai l t o ens ur e t hat pr ogr am com m i t m ent s ar e doc um ent ed i n t h e UF S A R.I n a l et t er dat ed Decem ber 3, 2006, t he appl i cant pr ov i ded add i t i onal com m i t m ent s f or enhanc i ng t he AS M E S ect i on XI , Subsec t i on I W E agi ng m anagem ent pr ogr am. T he new c om m i t m ent 27 i t em s ar e:14.
U T t hi ck ness m easu r em ent s wi l l be t aken f r om out si de t he dr y wel l i n t he s and bed r egi on dur i ng t he 2008 r ef uel i ng out age on t he l ocal l y t hi nned ar eas ex am i ned dur i ng t he O ct ober 2006 r ef uel i ng out age. T he l ocal l y t hi nned ar eas ar e di st r i but ed bot h v er t i cal l y and ar ound t he per i m et er of t he dr y wel l i n al l t en bay s s uch t hat pot ent i al cor r osi on of t he dr y wel l she l l woul d be de t ect ed.15.
St ar t i ng i n 2010, dr y wel l she l l U T t hi ck ness m easu r em ent s wi l l be t aken f r om out si de t he dr y wel l i n t he s and bed r egi on i n t wo bay s pe r out age, suc h t hat in s p e c tio n s w ill b e p e r f o r m e d in a ll 1 0 b a ys w ith in a 1 0-ye a r p e r io d. T h e tw o b a ys wi t h t he m ost l ocal l y t hi nned ar eas (bay #1 and bay #13) wi l l be i nspe ct ed i n 2010.If th e U T e x a m in a tio n s yi e ld u n a c c e p ta b le re s u lts , th e n th e lo c a ll y th in n e d a re a s in a ll 1 0 b a ys w il l b e in s p e c te d in th e re f u e li n g o u ta g e th a t th e u n a c c e p ta b le re s u lts ar e I dent i f i ed.16.
Per f or m v i sual i nspe ct i ons of t he dr y wel l she l l i nsi de t he t r ench es i n bay #5 and bay#1 7 a n d t a k e U T m e a s u r e me n t s i n s i d e t h e s e t r e n c h e s i n 2 0 0 8 a t t h e s a me l ocat i ons ex am i ned i n 2006. R epeat (bot h t he UT and v i sual) i nspe ct i ons at re fu e l i n g o u ta g e s d u ri n g th e p e ri o d o f e x te n d e d o p e ra ti o n u n ti l th e tre n c h e s a re re s to re d to th e o rig in a l d e s ig n c o n f ig u ra tio n u s in g c o n c re te o r o th e r s u ita b le m at er i al t o pr event m oi st ur e col l ect i on i n t hese ar eas.17.
Per f or m v i sual i nspe ct i on of t he m oi st ur e bar r i er bet ween t he dr y wel l she l l and t he conc r et e f l oor cur b, i nst al l ed i nsi de t he dr y wel l dur i ng t he O ct ober 2006 r ef uel i ng out age, i n ac cor danc e wi t h AS M E S ect i on XI , Subsec t i on I W E dur i ng t he per i od of ex t ended o per at i on.D ur i ng t he Adv i sor y C om m i t t ee on React or Saf eguar ds (AC R S) m eet i ng on Febr uar y 1, 2007, t he appl i cant com m i t t ed t o per f or m an eng i neer i ng s t udy pr i or t o t he per i od of ex t ended 4-74 o p e ra tio n in o rd e r to id e n tify o p tio n s to e li m in a te o r re d u c e th e le a k a g e in th e re f u e li n g c a v ity l i ner. T he appl i cant al so c om m i t t ed t o per f or m a 3-D (di m ensi onal) f i ni t e-el em ent anal y si s of t he dr y wel l she l l pr i or t o ent er i ng t he per i od of ex t ended o per at i on.I n i t s l et t er dat ed Febr uar y 15, 2007, t he appl i cant con f i r m ed t he c om m i t m ent s i t m ade t o t he A C R S and r evi sed co m m i t m ent 27) A S M E S ect i on XI , S ubse ct i on I W E. T he a ppl i cant al so added c om m i t m ent s f or i nspe ct i on of t he dr y wel l t r ench es a nd f ul l sc ope of dr y wel l san d bed r egi on i nspe ct i ons. T he s peci f i c c om m i t m ent i t em s whi ch t he appl i cant added ar e:
1 8.
A m e rG e n w i l l p e rfo rm a 3-D fin i te e l e m e n t s tru c tu ra l a n a l y s i s o f th e p ri m a ry cont ai nm ent dr y we l l shel l usi ng m ode r n m et hod s and cur r ent dr y we l l shel l t hi ckness dat a t o bet t er quant i f y t he m ar gi n t hat ex i st s ab ov e t he Code r equi r ed m i ni m um f or b u c k li n g. T h e a n a ly s is w il l i n c lu d e s e n s iti v ity s tu d ie s to d e te rm in e th e d e g re e to w h ic h u n c e rta in tie s in th e s ize o f th in n e d a re a s a f f e c t C o d e m a rg in s. If th e a n a ly s is d e t e r mi n e s t h a t t h e d r y w e l l s h e l l d o e s n o t me e t r e q u i r e d t h i c k n e s s v a l u e s , t h e NR C wi l l be n ot i f i ed i n acco r dan ce w i t h 10 C FR 50 r equ i r em ent s.1 9.
A m e r G e n w i l l p e r form a n e n g i n e e r i n g s t u d y t o i n ve s t i g a t e c o s t-e ff e c t i ve r epl acem ent or r epai r opt i ons t o el i m i nat e or r educ e r eact or cav i t y l i ner l eaka ge.2 0.
A m e rG e n is c o m m itte d to p e rf o rm v is u a l a n d U T in s p e c tio n s o f th e d ryw e ll s h e ll in t he i nspe ct i on t r ench es i n dr y wel l bay s #5 and #1 7 dur i ng t he O y st er C r eek 2008 r ef uel i ng out age (see i t em 16 of Am er G en's I W E P r ogr am (C om m i t m ent 27), m ade i n i ts l e tt e r 2 1 3 0-0 6-2 0 4 2 6). A m e rG e n w i l l e x te n d th i s c o m m i tm e n t a n d a l s o p e rfo rm th e s e in s p e c tio n s d u rin g th e 2 0 1 0 re f u e li n g o u ta g e. In a d d iti o n , A m e rG e n w il l m oni t or t he t wo t r ench es f or t he pr esen ce o f wat er dur i ng r ef uel i ng out ages. Vi sual and UT i nspe ct i ons of t he s hel l wi t hi n t he t r ench es wi l l con t i nue t o be pe r f or m ed unt i l no wat er i s i dent i f i ed i n t he t r ench es f or t wo con sec ut i v e r ef uel i ng out ages , at w h ic h tim e th e tre n c h e s w il l b e re s to re d to th e ir o rig in a l d e s ig n c o n f ig u ra tio n (e.g., r ef i l l ed wi t h co ncr et e) t o m i ni m i z e t he r i sk of f ut ur e co r r osi on.21.
Per f or m t he f ul l sc ope of dr y wel l san d bed r egi on i nspe ct i ons pr i or t o t he per i od of ex t ended o per at i on and t hen ev er y ot her r ef uel i ng out age t her eaf t er. T he f ul l sc ope is d e f in e d a s:
- U T m easu r em ent s f r om i nsi de t he dr y wel l (I t em 1)
- V i s u a l i n s p e c t i o n s o f t h e d r y w e l l e xt e r n a l s h e l l e p o xy coat i ng i n al l 10 bay s (I t em 4)
- I nspe ct i on of t he s eal at t he j unct i on bet ween t he s and bed r egi on c oncr et e and t he em bedded dr y wel l she l l (I t em 12)
- U T m easu r em ent s at t he ex t er nal l ocal l y t hi nned ar eas i nspe ct ed i n 2006 (I t em s 9 a nd 14)T he st af f , consi st ent wi t h A C R S r ecom m end at i ons, i den t i f i ed t hese i t em s as l i cense cond i t i ons.T h e s ta f f f in d s th e a p p li c a n t's a d d iti o n a l c o m m itm e n ts f o r e n h a n c in g th e A S M E S e c tio n X I, S u b s e c tio n IW E a g in g m a n a g e m e n t p ro g ra m a c c e p ta b le; th e re f o re , th e c o n c e rn d e s c rib e d in R AI 4.7.2-5 i s r esol v ed.O n th e b a s i s o f it s re v i e w o f th e U F S A R s u p p l e m e n t, th e s ta ff c o n c l u d e s th a t t h e s u m m a ry desc r i pt i on of t he appl i cant's ac t i ons t o addr ess dr y wel l cor r osi on i s ad equat e.
4-75 4.7.2.4 Conc l us i on O n t he bas i s of i t s r ev i ew and t he l i cens e co ndi t i ons di sc uss ed abov e, t he s t af f con cl udes t hat th e a p p li c a n t h a s d e m o n s tra te d , p u rs u a n t to 1 0 C F R 5 4.2 1 (c)(1)(iii), th a t, fo r th e d ryw e ll cor r osi on T LAA , t he ef f ect s of agi ng on t he i nt ended f unct i on(s) wi l l be ade quat el y m anaged f or t he per i od of ex t ended o per at i on. T he s t af f al so c oncl udes t hat t he UF SA R sup pl em ent con t ai ns an appr opr i at e su m m ar y des cr i pt i on of t he ac t i v i t i es f or m anagi ng t he ef f ect s of agi ng and t he T L A A e v a l u a ti o n , a s re q u i re d b y 1 0 C F R 5 4.2 1 (d).
4.7.3 Eq ui pm en t Pool an d Rea ct or Cav i t y W al l s Reb ar Cor r os i on4.7.3.1 Su m m ar y o f Te ch ni ca l I nf or m at i on i n t he Appl i ca t i on I n LRA Sect i on 4.7.3, t he appl i cant sum m ar i z ed t he ev al uat i on of equi pm ent pool and r eact or cav i t y wal l s r ebar cor r osi on f or t he per i od of ex t ended o per at i on. A l et t er t o t he NR C di sc uss i ng
Section 5 5-1 S E CT I ON 5 RE V I E W BY T HE A DV I S ORY COM M I T T E E ON RE A CT OR S A F E GU A RD ST he NR C st af f i ss ued i t s s af et y ev al uat i on r epor t (SE R) wi t h open i t em s r el at ed t o t he r enewal of t h e o p e r a t i n g l i c e n s e f o r Oy s t e r Cr e e k Ge n e r a t i n g S t a t i o n (OCGS) o n A u g u s t 1 8 , 2 0 0 6. On O ct ober 3, 2006, t he appl i cant pr esen t ed i t s l i cens e r enewal appl i cat i on, and t he s t af f pr esen t ed i t s f i ndi ngs t o t he AC R S P l ant Li cens e R enewal Subcom m i t t ee.T he NR C st af f i ss ued an updat ed SE R on Decem ber 29, 2006. O n Ja nuar y 18, 2007, t he appl i cant pr esen t ed i t s l i cens e r enewal appl i cat i on, t he s t af f pr esen t ed i t s r ev i ew f i ndi ngs and t he re p re s e n ta tiv e f o r th e in te rv e n e rs p re s e n te d th e ir in f o rm a tio n , w h ic h w e re a s s o c ia te d w ith d ryw e ll shel l i nt egr i t y , t o t he AC R S P l ant Li cens e R enewal Subcom m i t t ee.D ur i ng t he 539 m eet i ng of t he AC R S on Febr uar y 1, 2007, t he AC R S com pl et ed i t s r ev i ew of th t he O y st er C r eek l i cens e r enewal appl i cat i on and t he NR C st af f's SER. T he AC R S docum ent ed i t s f i ndi ngs i n a l et t er t o t he Com m i ss i on dat ed Febr uar y 8, 2007. A copy of t hi s l et t er and t he st af f's r espo nse i s pr ov i ded on t he f ol l owi ng page s of t hi s SER Sect i on.C onsi st ent wi t h AC R S r ecom m endat i on, t he s t af f added t wo addi t i onal l i cens e co ndi t i ons t o t he S E R.
5-2THIS PAGE IS IN TENTION ALLY LEF T BLAN K.
5-3 R SR-2233 Febr uar y 8, 2007T h e H o n o ra b le D a le E. K le in C hai r m an U.S. N ucl ear R egul at or y C om m i ss i on W ashi ngt on, D C 20555-0001 SUBJ ECT:
REPORT ON TH E SA FE TY ASP ECTS OF THE L I CENSE RENEW AL A P P L I CA TI ON F OR TH E OY S TE R C RE E K GE NE RA TI NG S TA TI ON D ear C hai r m an Kl ei n: D ur i ng t he 539t h m eet i ng of t he Adv i sor y C om m i t t ee on React or Saf eguar ds, Febr uar y 1-3, 2007, we co m pl et ed our r ev i ew of t he l i cens e r enewal appl i cat i on f or t he O y st er C r eek G ener at i ng St at i on (O C G S) and t he upda t ed Saf et y Ev al uat i on Repor t (SE R) pr epar ed by t he N R C st af f. O ur Pl ant Li cens e R enewal Subcom m i t t ee al so r ev i ewed t hi s m at t er dur i ng m eet i ngs on O ct ober 3, 2006 a nd J anuar y 18, 2007. D ur i ng t hese r ev i ews, we had t he bene f i t of di sc uss i ons wi t h r epr esen t at i v es o f t he NR C st af f and i t s c ont r act or Sandi a N at i onal Labor at or i es (S N L), m e m b e rs o f th e p u b li c , a n d A m e rG e n E n e rg y C o m p a n y, L L C (A m e rG e n) a n d its cont r act or s. W e al so h ad t he bene f i t of t he doc um ent s r ef er ence d. T hi s r epor t f ul f i l l s t he r equi r em ent s of 10 CF R 54.25 t hat t he AC R S r ev i ew and r epor t on al l l i cens e r enewal a p p li c a tio n s. RE COM ME ND A TI ONS 1.
W i t h t he i ncor por at i on of t he c ondi t i ons desc r i bed i n R ecom m endat i ons 2, 3, and 4, t he appl i cat i on f or l i cens e r enewal f or O C G S shoul d be ap pr ov ed.2.
W e co ncur wi t h t he s t af f's pr opos al t o i m pose l i cens e co ndi t i ons t o i ncr ease t he fre q u e n c y o f th e d ry w e l l i n s p e c ti o n s a n d to m o n i to r th e tw o d ry w e l l tre n c h e s to e n s u re th a t th e s o u rc e s o f w a te r a re id e n tifie d a n d e li m in a te d. 3.
T h e s ta f f s h o u ld a d d a li c e n s e c o n d iti o n to e n s u re th a t th e a p p li c a n t fu lfills its c o m m itm e n t to p e rf o rm a n e n g in e e rin g s tu d y p rio r to th e p e rio d o f e x te n d e d o p e ra tio n to i d e n ti fy o p ti o n s to e l i m i n a te o r re d u c e th e l e a k a g e i n th e O C G S re fu e l i n g c a v i ty l i n e r.4.
T h e s ta f f s h o u ld a d d a li c e n s e c o n d iti o n to e n s u re th a t th e a p p li c a n t fu lfills its c o m m itm e n t to p e rf o rm a 3-D (d im e n s io n a l) fin ite-e le m e n t a n a ly s is o f th e d ryw e ll s h e ll p rio r to e n te rin g th e p e rio d o f e x te n d e d o p e ra tio n.
5-4 DI S CU S S I ON T h e O ys te r C r e e k G e n e r a tin g S ta tio n is lo c a te d in L a c e y T o w n s h ip , O c e a n C o u n ty, N e w J e r s e y, appr ox i m at el y 2 m i l es s out h of t he c om m uni t y of For ked R i v er , 2 m i l es i nl and f r om t he s hor e of Bar negat Bay , and 9 m i l es s out h of T om s Ri v er , N ew Jer sey. T he NR C i ss ued t he pr ov i si onal o p e ra tin g li c e n s e f o r O C G S o n A p ril 9 , 1 9 6 9 a n d th e o p e ra tin g li c e n s e o n J u ly 2 , 1 9 9 1. O C G S is a si ngl e uni t f aci l i t y wi t h a s i ngl e cy cl e, f or ced ci r cul at i on boi l i ng wat er r eact or (BW R)-2 wi t h a M ar k 1 c ont ai nm ent. T he nuc l ear st eam sup pl y sy st em was f ur ni shed by G ener al El ect r i c an d t he bal ance of t he pl ant was o r i gi nal l y des i gned an d co nst r uct ed by Bur ns & R oe. T he l i cens ed power out put i s 19 30 MW t wi t h a des i gn el ect r i cal out put of appr ox i m at el y 650 MW e. T he appl i cant , Am er G en r eques t ed r enewal of t he O C G S oper at i ng l i cens e f or 20 y ear s be y ond t he cur r ent l i cens e t er m , whi ch e x pi r es o n Apr i l 9, 2009.D u rin g th e 1 9 8 0 s , th e li c e n s e e d is c o v e re d c o rro s io n o n th e o u ts id e w a ll o f th e O C G S d ryw e ll shel l. Al t hough s om e co r r osi on had occ ur r ed i n t he uppe r she l l r egi on, t he m aj or i t y had oc cur r ed i n a r egi on near t he bas e of t he s hel l wher e t he s hel l was p ar t i al l y sup por t ed by a sa nd bed. T he l i cens ee det er m i ned t hat wat er had be en l eaki ng t hr ough f l aws i n t he r ef uel i ng c av i t y l i ner dur i ng r ef uel i ng oper at i ons. T hi s wat er had m i gr at ed down t he out si de of t he dr y wel l she l l and i nt o t he s a n d b e d. A s p a r t o f t h e c o r r e c t i ve a c t i o n s , t h e l i c e n s e e r e m o ve d t h e s a n d a n d a p p l i e d a n e p o xy coat i ng t o t he out si de of t he s hel l i n t he s and bed r egi on. I n addi t i on, r epai r s wer e m ade t o t he r ef uel i ng pool l i ner and t he c oncr et e dr ai n t r ough un der t he r ef uel i ng s eal. T hese r epai r s r educ ed th e le a k a g e a n d ro u te d a n y l e a k a g e to a d ra in li n e ra th e r th a n d o w n th e o u ts id e o f th e d ryw e ll s h e ll. T o f u rth e r re d u c e le a k a g e , th e li c e n s e e a p p li e d s trip p a b le c o a tin g s to th e li n e r d u rin g a ll b u t o n e o f th e s u b s e q u e n t re f u e li n g o u ta g e s. T h e li c e n s e e p e rf o rm e d u ltra s o n ic te s tin g (U T) to det er m i ne t he as-f ound c ondi t i on of t he dr y wel l she l l and pe r f or m ed a s t r uct ur al anal y si s i n 1992 to d e m o n s tra te a c c e p ta b il ity o f th e c o n ta in m e n t in th e d e g ra d e d c o n d iti o n. T h e 1 9 9 2 s tru c tu ra l a n a ly s is w a s re v ie w e d a n d a p p ro v e d b y th e N R C s ta f f. T h is a n a ly s is i ncl uded a det er m i nat i on of t he s t r ess es i n t he t hi nned r egi on unde r t he des i gn pr ess ur e l oads and an ev al uat i on of t he pot ent i al f or buc kl i ng dur i ng nor m al oper at i ons and pos t ul at ed ac ci dent c o n d i t i o n s. Th e b u c k l i n g a n a l y s i s u t i l i z e d Amer i c a n So c i e t y o f Me c h a n i c a l En g i n e e r s (ASM E)C ode Case N-284, R ev i si on 1. T he s t af f acc ept ed t he us e of t hi s Code C ase i n t he 1992 a n a l y s i s. I n s u p p o r t o f t h e r e v i e w o f t h e OCGS l i c e n s e r e n e w a l a p p l i c a t i o n , t h e s t a f f h a d S NL per f or m a co nf i r m at or y st r uct ur al anal y si s. Bot h anal y ses dem onst r at ed t hat t he dr y wel l she l l m et t he m i ni m um AS M E C ode r equi r em ent s f or buc kl i ng. H owev er , t he am ount of m ar gi n abov e t he C o d e m in im u m d e p e n d e d o n th e a p p li c a b il ity o f th e in c re a s e in th e b u c k li n g c a p a c ity d u e to t ensi l e st r ess es o r t hogona l t o t he appl i ed c om pr ess i v e st r ess es c om put ed ac cor di ng t o t he Code C ase. D ur i ng t he J anuar y 18, 2007 m eet i ng, t he Subcom m i t t ee r eques t ed addi t i onal j ust i f i cat i on f or usi ng t he i ncr ease d ca paci t y f act or. At our Febr uar y m eet i ng, D r. C. Mi l l er , t he aut hor of t he A S M E C o d e C a s e , d e s c rib e d th e te c h n ic a l b a s is f o r th e C o d e C a s e a n d p re s e n te d te s t re s u lts to d e m o n s tra te th a t th e in c re a s e d c a p a c ity f a c to r w a s a p p li c a b le to O C G S. T h e in c re a s e d c a p a c ity f act or use d i n t he 1992 anal y si s pr ov i ded by t he appl i cant was b ased on r esul t s f or m et al cy l i nder s. D r. Mi l l er sho wed r esul t s of t est s c onduc t ed on m et al sph er es whi ch d em onst r at ed th a t th e re s u lts f o r c yl in d e rs w e re c o n s e rv a tiv e f o r s p h e ric a l s h e ll s. T h e s ta f f re a f f irm e d its p o s i t i o n t h a t t h e u s e o f t h e i n c r e a s e d c a p a c i t y f a c t o r i s a p p r o p r i a t e f o r t h e a n a l y s i s o f t h e OCGS dr y wel l she l l. W e co ncur wi t h t hi s po si t i on.T h e 1 9 9 2 s tru c tu ra l a n a ly s is w a s b a s e d o n th e a s s u m p tio n th a t th e s h e ll is u n ifo rm ly th in n e d in t he s and bed r egi on. T he appl i cant has com m i t t ed t o per f or m a 3-D f i ni t e-el em ent anal y si s of t he 5-5 O G C S d ry w e l l to d e te rm i n e th e m a rg i n o f th e s h e l l i n th e a s-fo u n d c o n d i ti o n u s i n g m o d e rn m et hods. T hi s an al y si s wi l l pr ov i de a m or e ac cur at e quant i f i cat i on of t he m ar gi n abov e t he Code r equi r ed m i ni m um f or buc kl i ng. T he appl i cant has com m i t t ed t o co m pl et e t he anal y si s pr i or t o t he per i od of ex t ended o per at i on. W e co m m end t he appl i cant f or t hi s ac t i on and woul d l i ke t o be br i ef ed by t he s t af f on t he r esul t s when t hey bec om e av ai l abl e. Al t hough i t i s an t i ci pat ed t hat t he anal y si s wi l l dem onst r at e addi t i onal m ar gi n abov e t he Code r equi r ed m i ni m um , t he appl i cant shou l d co m pl et e t hi s an al y si s i n a t i m el y m anner pr i or t o ent er i ng t he per i od of ex t ended oper at i on i n or der t o i dent i f y and r esol v e any unex pect ed r esul t s. T he anal y si s s houl d i ncl ude sens i t i v i t y st udi es t o det er m i ne t he degr ee t o whi ch u ncer t ai nt i es i n t he s i z e of t hi nned ar eas af f ect t he Code m ar gi ns. T he s t af f sho ul d i m pose a l i cens e co ndi t i on t o ens ur e t hat t he appl i cant com pl et es t he anal y si s pr i or t o ent er i ng t he per i od of ex t ended o per at i on.I n 2006, t he appl i cant per f or m ed addi t i onal U T and v i sual i nspe ct i ons of t he dr y wel l she l l. W hen com par ed t o t he pr ev i ous U T , t he 2006 r esul t s c onf i r m ed t hat t he c or r ect i v e ac t i ons t aken i n t he sand bed r egi on had been ef f ect i v e and t hat t he c or r osi on had been ar r est ed or at l east t hat t he c o rro s i o n ra te s w e re v e ry l o w (i.e., w i th i n th e d a ta s c a tt e r). T h e e p o x y c o a ti n g a p p e a re d i n v e ry good c ondi t i on wi t h no ev i denc e of degr adat i on whi ch i s al so c onsi st ent wi t h t he c oncl usi on t hat t he c or r osi on has been e f f ect i v el y ar r est ed. T hese ex am i nat i ons al so d em onst r at ed t hat t he cor r osi on r at e i n t he uppe r she l l r egi on and t he em bedded f l oor r egi ons r em ai ned s uf f i ci ent l y l ow t o dem onst r at e st r uct ur al i nt egr i t y dur i ng t he per i od of ex t ended o per at i on. T he appl i cant has com m i t t ed t o per f or m U T and v i sual i nspe ct i ons of t he dr y wel l she l l dur i ng t he per i od of ex t ended o p e ra tio n. B e c a u s e o f th e re la tiv e ly s m a ll m a rg in a b o v e th e C o d e m in im u m a g a in s t b u c k li n g in th e s a n d b e d re g io n s h o w n b y c u rre n t a n a ly s e s , th e s ta f f is p ro p o s in g a li c e n s e c o n d iti o n to i n c re a s e th e fre q u e n c y o f d ry w e l l i n s p e c ti o n s a n d U T i n th e s a n d b e d re g i o n to a l l 1 0 b a y s e v e ry o th e r re f u e li n g o u ta g e f o r th e e x te n d e d p e rio d o f o p e ra tio n. In c re a s e d in s p e c tio n s w il l re s u lt i n addi t i onal r adi at i on ex posu r e t o per sonn el i nv ol v ed i n t he i nspe ct i ons. T her ef or e, t he appl i cant shou l d be al l owed t o i ncr ease t he per i od bet ween i nspe ct i ons i f i t dem onst r at es i ncr ease d m ar gi n t hr ough an al y si s or i f t he ongo i ng i nspe ct i ons cont i nue t o dem onst r at e t hat t he c or r osi on has been s uf f i ci ent l y ar r est ed. W i t h t hi s pr ov i si on, we agr ee wi t h t hi s l i cens e co ndi t i on. T he 2006 ex am i nat i ons r ev eal ed t hat when t he c av i t y was f l ooded f or r ef uel i ng, wat er l eaka ge w a s s til l o c c u rrin g. T h is le a k a g e o f a p p ro x im a te ly 1 g a ll o n p e r m in u te is w e ll w ith in th e c a p a c ity o f th e d ra in a s lo n g a s th e d ra in s ys te m is w o rk in g p ro p e rly. T h e p u rp o s e o f th e d ra in s ys te m is t o cat ch w at er t hat m ay l eak p ast a f ai l ed r ef uel i ng se al or l i ner and di v er t t he w at er t o sum ps, and pr ev ent i t f r om com i ng i nt o co nt act wi t h t he out si de of t he dr y wel l she l l. Leak age i s no t ex pect ed t o oc cur as p ar t of nor m al oper at i on wi t h pr oper l y m ai nt ai ned equ i pm ent and s tru c tu re s. T h e a p p li c a n t h a s c o m m itte d to c o n tin u e m o n ito rin g f o r le a k a g e o f th e re f u e li n g c a v ity li n e r a n d o th e r w a te r s o u rc e s a s s o c ia te d w ith th e d ryw e ll. T h e a p p li c a n t h a s a ls o c o m m itte d to c o m p le te a n e n g in e e rin g s tu d y to id e n tify c o s t-e f f e c tiv e re p a ir o r re p la c e m e n t o p tio n s to e li m in a te th e re f u e li n g c a v ity li n e r le a k a g e. T h e e n g in e e rin g s tu d y w il l b e c o m p le te d p rio r to e n te rin g th e p e rio d o f e x te n d e d o p e ra tio n. W e a g re e th a t e f f o rts s h o u ld b e m a d e to e li m in a te ro u t i n e l e a k a g e i n o rd e r t o p ro vi d e i n c re a s e d p ro t e c t i o n a g a i n s t fu rt h e r d e g ra d a t i o n. T h e s t a ff shou l d i m pose a l i cens e co ndi t i on t o ens ur e t he s t udy i s c om pl et ed by t he appl i cant pr i or t o t he per i od of ex t ended o per at i on.D ur i ng t he 2006 r ef uel i ng out age, t he appl i cant di sc ov er ed wat er i n t wo t r ench es t hat had be en pr ev i ousl y ex cav at ed t o al l ow acc ess t o and i nspe ct i on of t he i nsi de of t he s hel l i n t he em bedded r egi on. T he appl i cant det er m i ned t hat t he wat er had c om e f r om nor m al oper at i on and m ai nt enanc e ac t i v i t i es. T he wat er had m i gr at ed t o t he t r ench es d ue t o a bl ock ed dr ai n t ube i n t he 5-6 sub-pi l e ar ea and t he l ack of a se al bet ween t he s hel l and c oncr et e cu r b. T he appl i cant r epai r ed t he dr ai n t ube and i nst al l ed a s eal i n t he gap bet ween t he s hel l and c oncr et e cu r b. T he appl i cant i nt ends t o f i l l t hese t r ench es a f t er t wo con sec ut i v e out ages i n whi ch n o wat er i s ob ser v ed.H av i ng t he t r ench es o pen i s be nef i ci al f or i dent i f y i ng dr ai nage i ss ues, but i t i ncr ease s t he r i sk of addi t i onal cor r osi on bec ause i t pr ov i des an open ar ea i n whi ch wat er can be t r apped a gai nst t he shel l. T he s t af f i s pr opos i ng a l i cens e co ndi t i on t hat woul d r equi r e t he appl i cant t o l eav e t he t r ench es o pen and m oni t or t hem dur i ng eac h r ef uel i ng out age unt i l suc h t i m e t hat t he appl i cant can dem onst r at e t hat t he wat er sou r ces hav e been i dent i f i ed and el i m i nat ed. W e agr ee wi t h t he m oni t or i ng of t he t r ench es t o ens ur e t he el i m i nat i on of t he s our ces of wat er. H owev er , l eav i ng t he t r ench es o pen l onger t han nec ess ar y i ncr ease s t he r i sk of f ut ur e co r r osi on. T her ef or e, t he ap pl i c an t s ho ul d n ot be un ne c es s ar i l y de l ay ed i n r ep ai r i ng t he t r en c he s. W i t h t hi s pr ov i s i on , we a g re e w ith th e li c e n s e c o n d iti o n p ro p o s e d b y th e s ta f f. I n t he upda t ed SE R , t he s t af f doc um ent s i t s r ev i ew of t he l i cens e r enewal appl i cat i on and ot her i nf or m at i on s ubm i t t ed by Am er G en and obt ai ned dur i ng an a udi t and i nspe ct i ons cond uct ed at t he p l ant si t e. T he st af f r evi ew ed t he co m pl et ene ss of t he a ppl i cant's i den t i f i cat i on o f st r uct ur es, sy st em s, and c om ponent s (SS C s) t hat ar e wi t hi n t he s cope of l i cens e r enewal; t he i nt egr at ed p l a n t a s s e s s me n t p r o c e s s; t h e a p p l i c a n t's i d e n t i f i c a t i o n o f t h e p l a u s i b l e a g i n g me c h a n i s ms ass oci at ed wi t h pas si v e, l ong-l i v ed c om ponent s; t he adeq uacy of t he appl i cant's ag i ng m anagem ent pr ogr am s (AM Ps); and t he i dent i f i cat i on and ass ess m ent of t i m e-l i m i t ed agi ng a n a ly s e s (T L A A s) re q u irin g re v ie w. T he O C G S appl i cat i on ei t her dem onst r at es c onsi st ency wi t h t he G ener i c Agi ng Les sons Lear ned (G ALL) R epor t or doc um ent s de v i at i ons f r om t he appr oach es s peci f i ed i n t he G ALL R epor t. T he st af f r ev i ewed t hi s ap pl i cat i on i n ac cor danc e wi t h N U R EG-1800, t he "St andar d R ev i ew Pl an f or R e v i e w o f L i c e n s e R e n e w a l A p p l i c a ti o n s fo r N u c l e a r P o w e r P l a n ts." T he a ppl i cant i den t i f i ed t hose S S C s t hat f al l wi t hi n t he sco pe o f l i cense r ene wa l. Fo r t hese SS C s, t he appl i cant per f or m ed a c om pr ehens i v e agi ng m anagem ent r ev i ew. Based on t he r esul t s of t hi s r ev i ew, t he appl i cant wi l l i m pl em ent 57 AM Ps f or l i cens e r enewal i ncl udi ng ex i st i ng, enhanc ed, and ne w pr ogr am s. I n t he SE R , t he s t af f con cl udes t hat t he appl i cant has appr opr i at el y i dent i f i ed SS C s wi t hi n t he s cope of l i cens e r enewal and t hat t he AM Ps desc r i bed b y t h e a p p l i c a n t a r e a p p r o p r i a t e a n d s u ff i c i e n t t o m a n a g e a g i n g o f l o n g-l i ve d p a s s i ve com pon ent s t hat ar e w i t hi n t he sco pe o f l i cense r ene wa l. W i t h t he i ncor por at i on o f t he l i cense cond i t i ons desc r i bed i n R ecom m endat i ons 2, 3 and 4 , we agr ee wi t h t hi s c oncl usi on.T he s t af f con duct ed i nspe ct i ons and an audi t of t he l i cens e r enewal appl i cat i on. T he pur pose of th e in s p e c tio n s w a s to v e rif y th a t th e s c o p in g a n d s c re e n in g m e th o d o lo g ie s a re c o n s is te n t w ith th e re g u l a ti o n s a n d a re a d e q u a te l y re fle c te d i n th e a p p l i c a ti o n. I n a d d i ti o n , t h e i n s p e c to rs p e r s o n a l l y e xa m i n e d s e l e c t e d a r e a s o f t h e s a n d b e d r e g i o n t o ve r i fy t h e c o n d i t i o n o f t h e e p o xy coat i ng. T he audi t con f i r m ed t he appr opr i at enes s of t he AM Ps and t he agi ng m anagem ent re v i e w s. B a s e d o n th e i n s p e c ti o n s a n d a u d i t, th e s ta ff c o n c l u d e d th a t t h e s e p ro g ra m s a re c o n s i s t e n t w i t h t h e d e s c ri p t i o n s c o n t a i n e d i n t h e O C G S l i c e n s e re n e w a l a p p l i c a t i o n. T h e s t a ff a l s o c o n c l u d e d th a t t h e e x i s ti n g p ro g ra m s , t o b e c re d i te d a s A M P s fo r l i c e n s e re n e w a l , a re g e n e ra ll y fu n c tio n in g w e ll a n d th a t th e a p p li c a n t h a s e s ta b li s h e d a n im p le m e n ta tio n p la n in its com m i t m ent t r acki ng sy st em t o en sur e t i m el y com pl et i on o f t he l i cense r ene wa l com m i t m ent s.T he appl i cant i dent i f i ed t hose sy st em s an d co m ponent s r equi r i ng T LAA s an d r eev al uat ed t hem f or 20 m or e y ear s of oper at i on. Af f ect ed T LAA s i ncl ude t hose ass oci at ed wi t h neut r on 5-7 em br i t t l em ent , m et al f at i gue, i r r adi at i on-ass i st ed s t r ess cor r osi on c r ack i ng, env i r onm ent al q u a l i fi c a t i o n o f e l e c t ri c a l e q u i p m e n t , a n d s t re s s re l a xa t i o n o f h o l d-d o w n b o l t s. T h e s t a ff c o n c l u d e d t h a t t h e a p p l i c a n t h a s p ro vi d e d a n a d e q u a t e l i s t o f T L A A s. F u rt h e r, t h e s t a ff conc l uded t hat i n al l cas es t he appl i cant has m et t he r equi r em ent s of t he l i cens e r enewal r ul e by dem onst r at i ng t hat t he T LAA s wi l l r em ai n v al i d f or t he per i od of ex t ended o per at i on, or t hat t he T LAA s ha v e been pr oj ect ed t o t he end of t he per i od of ex t ended o per at i on, or t hat t he agi ng ef f ect s wi l l be ade quat el y m anaged f or t he per i od of ex t ended o per at i on. W i t h t he i ncor por at i on of t he l i cens e co ndi t i ons desc r i bed i n R ecom m endat i ons 2, 3 and 4 , we co ncur wi t h t he s t af f t hat O C G S T LAA s ha v e been pr oper l y i dent i f i ed and t hat cr i t er i a su ppor t i ng 20 m or e y ear s of o p e ra tio n h a v e b e e n m e t.W i t h t he i ncor por at i on of t he l i cens e co ndi t i ons desc r i bed i n R ecom m endat i ons 2, 3, and 4, no i ss ues r el at ed t o t he m at t er s de sc r i bed i n 10 CFR 54.29(a)(1) and (a)(2) pr ecl ude r enewal of t he oper at i ng l i cens e f or O C G S. T he pr ogr am s es t abl i shed and c om m i t t ed t o by Am er G en pr ov i de re a s o n a b le a s s u ra n c e th a t O C G S c a n b e o p e ra te d in a c c o rd a n c e w ith its c u rre n t li c e n s in g b a s is f or t he per i od of ex t ended o per at i on wi t hout undue r i sk t o t he heal t h and s af et y of t he publ i c an d t he NR C sho ul d appr ov e t he Am er G en appl i cat i on f or r enewal of t he oper at i ng l i cens e f or OCG S.
S in c e re ly , /R A/
W i l l i am J. S hack C hai r m an R ef er ence s:
- U pdat ed Saf et y Ev al uat i on Repor t R el at ed t o t he Li cens e R enewal of O y st er C r eek G ener at i ng St at i on, D ecem ber 29, 2006.
- Saf et y Ev al uat i on Repor t wi t h O pen I t em s Rel at ed t o t he Li cens e R enewal of t he O y st er C r eek G ener at i ng St at i on, August 18, 2006.
- O y st er C r eek G ener at i ng St at i on- Appl i cat i on f or R enewed Oper at i ng Li cens es, Jul y 22, 2005.
- Suppl em ent al I nf or m at i on Rel at ed t o t he Agi ng Managem ent Pr ogr am f or t he O y st er C r eek D r y wel l Shel l , Assoc i at ed wi t h Am er G en's Li cens e R enewal Appl i cat i on, Jun e 20, 2 0 0 6.
- Audi t and Rev i ew R epor t f or Pl ant Agi ng Managem ent R ev i ews an d Pr ogr am s- O y st er C r eek G ener at i ng St at i on August 18, 2006.
- S u p p l e m e n ta l R e s p o n s e to N R C R e q u e s t fo r A d d i ti o n a l In fo rm a ti o n (R A I 2.5.1.1 9-1), dat ed Sept em ber 28, 2005, R el at ed t o O y st er C r eek G ener at i ng St at i on Li cens e R enewal Appl i cat i on, N ov em ber 11, 2005.
5-8
- O y s te r C re e k G e n e ra ti n g S ta ti o n - N R C L i c e n s e R e n e w a l In s p e c ti o n R e p o rt 050002 19/200600 7, Sept em ber 21, 2006
- M e m o ra n d u m d a te d D e c e m b e r 1 4 , 2 0 0 6 f ro m L o u is e L u n d to J o h n L a rk in s , S u b je c t: R ev i ew Backgr ound Mat er i al s f or t he Meet i ng of t he Li cens e R enewal Subcom m i t t ee Schedul ed on J anuar y 18, 2007, R el at ed t o t he I nt er i m R ev i ew of t he Li cens e R enewal of t he O y st er C r eek G ener at i ng St at i on. ML063470557
- M em or andum dat e D ecem ber 8, 2006 f r om Mi chae l P. G al l agher t o t he U.S. N ucl ear R egu l at or y C om m i ssi on, S ubj ect: S ubm i t t al of I nf or m at i on t o A C R S P l ant Li cense R enewal Subcom m i t t ee Rel at ed t o Am er G en's Appl i cat i on f or R enewed Oper at i ng Li cens e f or O y st er C r eek G ener at i ng St at i on. ML063470532
- Sandi a N at i onal Labor at or i es Repor t "St r uct ur al I nt egr i t y Anal y si s of t he Degr aded D r y wel l C ont ai nm ent at t he O y st er C r eek N ucl ear G ener at i ng St at i on," Jan uar y 2007
- A S M E C ode C ase N-284-1, "M et al C ont ai nm ent S hel l B uckl i ng D esi gn M et hod s, C l ass M C , S e c tio n III, D iv is io n o n e , M a rc h 1 4 , 1 9 9 5."
- L e tt e r d a te d J a n u a ry 3 1 , 2 0 0 7 , fro m S e n a to r F ra n k L a u te n b e rg , S e n a to r R o b e rt M enende z , R epr esen t at i v e C hr i st opher H. Sm i t h, and Repr esen t at i v e Ji m Sax t on t o T he ACRS.
- L e tte r d a te d J a n u a ry 3 1 , 2 0 0 7 f ro m R ic h a rd W e b s te r, R u tg e rs E n v iro n m e n ta l L a w C li n ic t o t he AC R S, r egar di ng t he Saf et y Ev al uat i on Repor t f or O y st er C r eek N ucl ear Power P la n t.
- O y st er C r eek G ener at i ng St at i on-N R C I n-Ser v i ce I nspe ct i on and Li cens e R enewal C om m i t m ent Fol l owup I nspe ct i on Repor t 050002 1/200601 3, Jan uar y 17, 2007.
5-9 M ar ch 8 , 2007 D r. W i l l i am J. Shack, C hai r m an Adv i sor y C om m i t t ee on React or Saf eguar ds U.S. N ucl ear R egul at or y C om m i ss i onW ashi ngt on, D C 20555-0001 S UB J E CT:
RE S P ONS E TO A DV I S ORY COM MI TTE E ON R E A CTOR S A F E GUA RD S REPORT ON TH E SA FE TY ASP ECTS OF THE L I CENSE RENEW AL A P P L I CA TI ON F OR TH E OY S TE R C RE E K GE NE RA TI NG S TA TI ON D ear D r. S hack: D ur i ng t he 539 m eet i ng of t he Adv i sor y C om m i t t ee on React or Saf eguar ds (AC R S or t he th C om m i t t ee) hel d on Fe br uar y 1-3 , 200 7, t he A C R S com pl et ed i t s r evi ew of t he l i cense r enewal appl i cat i on (LR A) f or t he O y st er C r eek G ener at i ng St at i on (O C G S) and t he a s s o c i a te d fin a l s a fe ty e v a l u a ti o n re p o rt (S E R) p re p a re d b y th e U.S. N u c l e a r R e g u l a to ry C om m i ss i on (N R C) st af f. I n i t s f i nal r epor t , t he Com m i t t ee r ecom m ends r enewal of t he O C G S oper at i ng l i cens e i n co nj unct i on wi t h t he r ecom m endat i ons di sc uss ed i n y our l et t er dat ed Febr uar y 8, 2007. T he s t af f appr eci at es t he Com m i t t ee's ex pedi t i ous, obj ect i v e, and in-d e p th re v ie w o f th e L R A a n d th e s ta f f's f in a l S E R. T h e s ta f f a g re e s w ith th e C o m m itte e's r ecom m end at i ons: 1.
T h e s ta f f w il l i m p o s e a li c e n s e c o n d iti o n to in c re a s e th e f re q u e n c y o f th e d ryw e ll i nspe ct i ons and t o m oni t or t he t wo dr y wel l t r ench es t o ens ur e t hat t he s our ces of wat er ar e i dent i f i ed and el i m i nat ed.2.
T he s t af f wi l l ens ur e t hat t he appl i cant f ul f i l l s i t s c om m i t m ent t o (a) per f or m an e n g in e e rin g s tu d y p rio r to th e p e rio d o f e x te n d e d o p e ra tio n to id e n tify o p tio n s to e li m in a te o r re d u c e th e l e a k a g e i n th e O C G S re fu e l i n g c a v i ty l i n e r, a n d (b) p e rfo rm a 3-D (di m ensi onal) f i ni t e-el em ent anal y si s of t he dr y wel l she l l pr i or t o ent er i ng t he per i od of ex t ended o per at i on.T h e s ta f f re c o g n ize s th e A C R S's c o m m itm e n t to s a f e ty a n d a p p re c ia te s th e C o m m itte e's c o n tin u e d s u p p o rt o f th e li c e n s e re n e w a l p ro c e s s.
S in c e r e ly,
/RA/
L ui s A. R ey es E x e c u ti v e D i re c to r
f or O per at i onsc c:
C h a irm a n K le inC om m i ss i oner McG af f i ganC o m m is s io n e r M e rrif ie ldC om m i ssi one r Jacz koC om m i ss i oner Ly onsS E CY 5-10M ar ch 8 , 2007 D r. W i l l i am J. Shack, C hai r m an Adv i sor y C om m i t t ee on React or Saf eguar ds U.S. N ucl ear R egul at or y C om m i ss i onW ashi ngt on, D C 20555-0001 S UB J E CT:
RE S P ONS E TO A DV I S ORY COM MI TTE E ON R E A CTOR S A F E GUA RD S REPORT ON TH E SA FE TY ASP ECTS OF THE L I CENSE RENEW AL A P P L I CA TI ON F OR TH E OY S TE R C RE E K GE NE RA TI NG S TA TI ON D ear D r. S hack: D ur i ng t he 539 m eet i ng of t he Adv i sor y C om m i t t ee on React or Saf eguar ds (AC R S or t he th C om m i t t ee) hel d on Fe br uar y 1-3 , 200 7, t he A C R S com pl et ed i t s r evi ew of t he l i cense r enewal appl i cat i on (LR A) f or t he O y st er C r eek G ener at i ng St at i on (O C G S) and t he a s s o c i a te d fin a l s a fe ty e v a l u a ti o n re p o rt (S E R) p re p a re d b y th e U.S. N u c l e a r R e g u l a to ry C om m i ss i on (N R C) st af f. I n i t s f i nal r epor t , t he Com m i t t ee r ecom m ends r enewal of t he O C G S oper at i ng l i cens e i n co nj unct i on wi t h t he r ecom m endat i ons di sc uss ed i n y our l et t er dat ed Febr uar y 8, 2007. T he s t af f appr eci at es t he Com m i t t ee's ex pedi t i ous, obj ect i v e, and in-d e p th re v ie w o f th e L R A a n d th e s ta f f's f in a l S E R. T h e s ta f f a g re e s w ith th e C o m m itte e's r ecom m end at i ons: 1.
T h e s ta f f w il l i m p o s e a li c e n s e c o n d iti o n to in c re a s e th e f re q u e n c y o f th e d ryw e ll i nspe ct i ons and t o m oni t or t he t wo dr y wel l t r ench es t o ens ur e t hat t he s our ces of wat er ar e i dent i f i ed and el i m i nat ed.2.
T he s t af f wi l l ens ur e t hat t he appl i cant f ul f i l l s i t s c om m i t m ent t o (a) per f or m an e n g in e e rin g s tu d y p rio r to th e p e rio d o f e x te n d e d o p e ra tio n to id e n tify o p tio n s to e li m in a te o r re d u c e th e l e a k a g e i n th e O C G S re fu e l i n g c a v i ty l i n e r, a n d (b) p e rfo rm a 3-D (di m ensi onal) f i ni t e-el em ent anal y si s of t he dr y wel l she l l pr i or t o ent er i ng t he per i od of ex t ended o per at i on.T h e s ta f f re c o g n ize s th e A C R S's c o m m itm e n t to s a f e ty a n d a p p re c ia te s th e C o m m itte e's c o n tin u e d s u p p o rt o f th e li c e n s e re n e w a l p ro c e s s.
S in c e r e ly,
/RA/
L ui s A. R ey es E x e c u ti v e D i re c to r
f or O per at i ons c c:
C h a irm a n K le inC om m i ss i oner McG af f i ganC o m m is s io n e r M e rrif ie ldC om m i ssi one r Jacz koC om m i ss i oner Ly onsS E CY DISTRIBUTION:
G 20070 105/LTR-07-01 04 See N ex t P age
ML070460081 O FFI CE:
PM:R LR A: DL R LA: RL RA:D LR T ech E d (A)B C: RL RA:D LR NA M E:
Y Edmo nds HC hang RS chaff DA T E:
02/2 1/07 02/2 2/07 02/2 1/07 02/2 3/07 OFFICE:
M Y oung (w/w dits)
PT Kuo JDy er (B Bog er for)
LR ey es DA T E:
02/2 6/07 02/2 7/07 03/0 2/07 03/0 8/07 OFF I CI A L RE CORD CO PY 5-11 Let t er t o W. Shack, f r om L. R ey es, dat ed: Mar ch 8 , 2007 S UB J E CT:
RE S P ONS E TO A DV I S ORY COM MI TTE E ON R E A CTOR S A F E GUA RD S REPORT ON TH E SA FE TY ASP ECTS OF THE L I CENSE RENEW AL A P P L I CA TI ON F OR OY S TE R C RE E K GE NE RA TI NG S TA TI ON HA RD COPY DL R R F E-M A IL: R W ei sm an G G a ll e tti D Shum SS m i t h (sr s3)S D u r a i s w a my R i dsEdoMai l C ent er R id s N rrD lr R i d s N rrD l rR l ra R i d s N rrD l rR l rb R i d s N rrD l rR l rc R i dsNr r D l r R eba R i dsNr r D l r R ebbRi d s Nr r De R i dsN r r D ci R i d s N r r e E e mb R i dsNr r D eEeeb R i d s N r r D e E q va R i dsN r r D ss R i d s N rrD n rl R i dsOgcM ai l C ent er R i dsNr r Ades R i dsAcr sMai l C ent er BS her on D C ol l i ns---------------D Ashl ey R Lauf er G M i l l er RB e l l a my , RI RC u r e t o n , RI J L i l l i e n d a h l , RI MM o d e s , RI MY o u n g , OGC R id s O p a M a il R i d s N rrD o rl OPA
Section 6 6-1 S E CT I ON 6 CONCL US I ONT he st af f of t he U.S. N ucl ear R egu l at or y C om m i ssi on (N R C or t he st af f) r evi ew ed t he l i cense r e n e w a l a p p l i c a t i o n (L RA) f o r Oy s t e r Cr e e k Ge n e r a t i n g S t a t i o n i n a c c o r d a n c e w i t h t h e NR C r egu l at i ons a nd N U R E G-180 0, R evi si on 1 , "S t and ar d R evi ew P l an f or R evi ew of Li cense R enewal Appl i cat i ons f or N ucl ear Power Pl ant s," dat ed Sept em ber 2005. T i t l e 10, Sect i on 54.29, of t he C ode of Feder al R egul at i ons (10 CF R 54.29) pr ov i des t he s t andar ds f or i ss uanc e of a r enewed l i cens e.O n t he b asi s of i t s r evi ew , t he st af f concl ude s t hat t he a ppl i cant ade qua t el y i den t i f i ed t hose sy st em s an d co m ponent s t hat ar e wi t hi n t he s cope of l i cens e r enewal , as r equi r ed by 10 C FR 54.4(a), and t hose sy st em s an d co m ponent s t hat ar e su bj ect t o an ag i ng m anagem ent r ev i ew, as r equi r ed by 10 CF R 54.21(a)(1). T he s t af f al so c oncl udes t hat t he appl i cant dem onst r at ed t hat t he agi ng ef f ect s wi l l be ade quat el y m anaged so t hat t he i nt ended f unct i ons wi l l be m ai nt ai ned c onsi st ent wi t h t he c ur r ent l i cens i ng bas i s (C LB) f or t he per i od of ex t ended o per at i on, as r equi r ed by 10 CF R 54.21(a)(3). Fur t her , t he s t af f con cl udes t hat t he appl i cant dem onst r at ed t hat (1) t he t i m e-l i m i t ed agi ng anal y ses (T LAA s) wi l l r em ai n v al i d f or t he per i od of ex t ended o per at i on, as r equi r ed by 10 CF R 54.21(c)(1)(i), (2) t he T LAA s ha d be en pr oj ec t ed t o t he en d o f t he pe r i od of ex t en de d o pe r at i on , as r eq ui r ed by 10 CFR 54.21(c)(1)(i i), or (3) t hat t he agi ng ef f ect s wi l l be ade quat el y m anaged f or t he per i od of ex t ended o per at i on, as r equi r ed by 10 CF R 54.21(c)(1)(i i i). O n t he bas i s of i t s ev al uat i on of th e L R A , t h e s ta ff fin d s th a t t h e re q u i re m e n ts o f 1 0 C F R 5 4.2 9 (a) h a v e b e e n m e t, th a t t h e re is re a s o n a b le a s s u ra n c e th a t th e a c tiv iti e s a u th o rize d b y th e re n e w e d li c e n s e w il l c o n tin u e to b e c o n d u c te d in a c c o rd a n c e w ith th e C L B , a n d th a t a n y c h a n g e s m a d e to th e p la n t's C L B in o rd e r to c o m p ly w ith th is p a ra g ra p h a re in a c c o rd w ith th e A c t a n d th e C o m m is s io n's r egu l at i ons.T h e s ta f f n o te s th a t a n y re q u ire m e n ts o f S u b p a rt A o f 1 0 C F R P a rt 5 1 a re d o c u m e n te d in S upp l em ent 28 t o N U R E G-143 7, " G ene r i c E nvi r onm ent al I m pact S t at em ent f or Li cense R ene wa l of N ucl ear P l ant s: R ega r di ng O y st er C r eek N ucl ear G ener at i ng St at i on Fi nal R e p o rt," d a te d J a n u a ry 2 0 0 7 (M L 0 7 0 1 0 0 2 3 4).
Appendix A Excerpts A-1 A PPEN D I X A C O M M I T M EN T S FO R LI C EN SE R EN EW A L O F O C G SD ur i ng t he r ev i ew of t he O y st er C r eek G ener at i ng St at i on (O C G S) l i cens e r enewal a p p l i c a ti o n (L R A) b y th e s ta ff o f th e U.S. N u c l e a r R e g u l a to ry C o m m i s s i o n (N R C) (t h e s ta ff), Am er G en Ener gy C om pany , LLC (t he appl i cant) m ade c om m i t m ent s r el at ed t o agi ng m a n a g e m e n t p ro g ra m s (A M P s) to m a n a g e th e a g in g e f f e c ts o f s tru c tu re s a n d c o m p o n e n ts (S C s) b o th p rio r to a n d d u rin g th e p e rio d o f e x te n d e d o p e ra tio n. T h e f o ll o w in g ta b le li s ts t hese com m i t m ent s al ong wi t h t he i m pl em ent at i on sch edu l es an d t he so ur ces f or each c o m m itm e n t.
A-18 A P P E ND I X A: COM MI T ME NT S F OR L I CE NS E RE NE W A L OF OCGS C O M M I TM E N T NUMBER I TE M N U M B E R AN D C O M M I TM E N TU F S AR S UP P L E ME NT L OCA T I ON (L R A A P P. A)E NH A NC E ME NT OR I MP L E ME NT A T I ON SCH EDU LE S OUR CE p ip e o r c o m p o n e n t h a s n o t b e e n p re v io u s ly r epl aced or r ecoa t ed, i f any suc h l ocat i ons r em ai n. (2)
Fi r e pr ot ect i on c om ponent s i n t he s cope of t h e p r o g r a m. (3)
Pi pi ng l ocat ed i nsi de t he v aul t i n t he s cope of t he pr ogr am. T he v aul t i s c onsi der ed a m anhol e t hat i s l ocat ed bet ween t he re a c to r b u il d in g a n d th e e x h a u s t tu n n e l.2 7)
ASM E S e c tio n X I, Subsect i on IW EEx i st i ng pr ogr am i s c r edi t ed. T he pr ogr am wi l l be enhanc ed t o i ncl ude: (1)
U l t r ason i c T est i ng (U T) t hi ckness m easu r em ent s of t he dr y wel l she l l i n t he sand bed r egi on wi l l be per f or m ed on a f r equenc y of ev er y 10 y ear s, ex cept t hat t he i ni t i al i nspe ct i on wi l l occ ur pr i or t o t he per i od of ex t ended o per at i on and t he s ub s eq ue nt i ns pe c t i on wi l l oc c ur t wo r ef uel i ng out ages af t er t he i ni t i al i nspe ct i on, t o pr ov i de ear l y con f i r m at i on t h a t c o r r o s i o n h a s b e e n a r r e s t e d. Th e UT m easu r em ent s wi l l be t aken f r om t he i nsi de of t he dr y wel l at t he s am e l ocat i ons wher e U T m easu r em ent s wer e per f or m ed A.1.27 Pr i or t o t he per i od of ex t ended o per at i on.Pr i or t o t he per i od of ex t ended o per at i on (com pl et ed dur i ng 2006 r ef uel i ng o u ta g e); t h e n e v e ry ot her r ef uel i ng out age Sect i on B.1.27 Let t er 2130-06-20354 Let t er 2130-06-20358 Let t er 2130-07-20464 Let t er 2130-06-20358 A P P E ND I X A: COM MI T ME NT S F OR L I CE NS E RE NE W A L OF OCGS C O M M I TM E N T NUMBER I TE M N U M B E R AN D C O M M I TM E N TU F S AR S UP P L E ME NT L OCA T I ON (L R A A P P. A)E NH A NC E ME NT OR I MP L E ME NT A T I ON SCH EDU LE S OUR CE A-19i n 1996. T he i nspe ct i on r esul t s wi l l be c o m p a re d to p re v io u s re s u lts. S ta tis tic a ll y si gni f i cant dev i at i ons f r om t he 1992 , 1 9 9 4 , a n d 1 9 9 6 U T re s u lts w il l re s u lt i n cor r ect i v e ac t i ons t hat i ncl ude t he f ol l owi ng:
- P e r f o r m a d d i t i o n a l UT m easu r em ent s t o co nf i r m t he r ead i ngs.
- N ot i f y N R C wi t hi n 48 ho ur s of conf i r m at i on of t he i dent i f i ed cond i t i on.
- C onduc t v i sual i nspe ct i on of t he ex t er nal sur f ace i n t he s and bed r egi on i n ar eas wher e any unex pect ed c or r osi on m ay be det ect ed.
- P e rf o rm e n g in e e rin g e v a lu a tio n to ass ess t he ex t ent of con di t i on and t o det er m i ne i f addi t i onal i n s p e c ti o n s a re re q u i re d to a s s u re d r yw e ll in te g r ity.
- Per f or m oper abi l i t y det er m i nat i on a n d ju s tific a tio n f o r o p e ra tio n u n til nex t i nspe ct i on.
A P P E ND I X A: COM MI T ME NT S F OR L I CE NS E RE NE W A L OF OCGS C O M M I TM E N T NUMBER I TE M N U M B E R AN D C O M M I TM E N TU F S AR S UP P L E ME NT L OCA T I ON (L R A A P P. A)E NH A NC E ME NT OR I MP L E ME NT A T I ON SCH EDU LE S OUR CE A-20T h e s e a c tio n s w il l b e c o m p le te d p rio r to r est ar t f r om t he as soc i at ed out age.N ot e: T he f r equenc y f or t he i nspe ct i ons desc r i bed i n i t em 1 (abov e) has been chan ged t o ev er y ot her r ef uel i ng out age, in a c c o rd a n c e w ith ite m 2 1 o f th e IW E I n s p e c t i o n P r o g r a m. (2)
A st r i ppabl e co at i ng wi l l be app l i ed t o t he r eact or cav i t y l i ner t o pr ev ent wat er in tru s io n in to th e g a p b e tw e e n th e d ryw e ll shi el d wal l and t he dr y wel l she l l dur i ng p e rio d s w h e n th e re a c to r c a v ity is f l ooded. (3)
T he r eact or cav i t y sea l l eaka ge t r ough dr ai ns a nd t he dr y wel l san d bed r egi on dr ai ns wi l l be m oni t or ed f or l eaka ge.
- T he s and bed r egi on dr ai ns wi l l be m oni t or ed dai l y dur i ng r ef uel i ng out ages. I f l eaka ge i s de t ect ed, p ro c e d u re s w il l b e in p la c e to det er m i ne t he s our ce o f l eaka ge and i nv est i gat e and a ddr ess t he im p a c t o f le a k a g e o n th e d ryw e ll R ef uel i ng out ages pr i or t o and d ur i ng t he per i od of ex t ended o per at i on P e rio d ic a ll y D ai l y dur i ng r ef uel i ng out age s.
A P P E ND I X A: COM MI T ME NT S F OR L I CE NS E RE NE W A L OF OCGS C O M M I TM E N T NUMBER I TE M N U M B E R AN D C O M M I TM E N TU F S AR S UP P L E ME NT L OCA T I ON (L R A A P P. A)E NH A NC E ME NT OR I MP L E ME NT A T I ON SCH EDU LE S OUR CE A-21 shel l , i ncl udi ng v er i f i cat i on of t he c o n d iti o n o f th e d ryw e ll s h e ll c o a tin g a n d m o is tu re b a rrie r (s e a l)i n t he s and bed r egi on and per f or m ance of U T ex am i nat i ons of t he sh el l i n t he u ppe r r egi ons.U T s wi l l al so b e per f or m ed on a ny ar eas i n t he s and bed r egi on wher e v i sual i nspe ct i on i ndi cat es t he c oat i ng i s da m aged an d c o r r o s i o n h a s o c c u r r e d. UT r esul t s wi l l be ev al uat ed per t he ex i st i ng pr ogr am. Any degr aded coat i ng or m oi st ur e bar r i er wi l l be r epai r ed. T hese act i ons wi l l be com pl et ed pr i or t o ex i t i ng t he ass oci at ed out age.
- T he s and bed r egi on dr ai ns wi l l be m oni t or ed quar t er l y dur i ng t he p la n t o p e ra tin g c yc le. If le a k a g e is id e n tifie d , th e s o u rc e o f w a te r w il l be i nv est i gat ed, cor r ect i v e ac t i ons t aken or pl anned a s ap pr opr i at e.I n addi t i on, i f l eaka ge i s de t ect ed, t he f ol l owi ng i t em s wi l l be p e r form e d d u r i n g t h e n e xt r ef uel i ng out age: Q uar t er l y dur i ng non-out age per i ods.
A P P E ND I X A: COM MI T ME NT S F OR L I CE NS E RE NE W A L OF OCGS C O M M I TM E N T NUMBER I TE M N U M B E R AN D C O M M I TM E N TU F S AR S UP P L E ME NT L OCA T I ON (L R A A P P. A)E NH A NC E ME NT OR I MP L E ME NT A T I ON SCH EDU LE S OUR CE A-22
- In s p e c tio n o f th e d ryw e ll s h e ll c o a tin g a n d m o is tu re b a rrie r (s e a l)i n t he af f ect ed bay s i n t he s and bed r egi on
- U T s of t he uppe r dr y wel l r egi on cons i st ent wi t h t he ex i st i ng pr ogr am
- U T s wi l l be per f or m ed on a ny ar eas i n t he s and bed r egi on wher e v i sual i nspe ct i on i ndi cat es t he c oat i ng i s da m aged an d cor r osi on has occ ur r ed
- U T r esul t s wi l l be ev al uat ed per th e e x is tin g p ro g ra m.
- A n y d e g ra d e d c o a ti n g o r m o i s tu re bar r i er wi l l be r epai r ed. (4)
Pr i or t o t he per i od of ex t ended o per at i on, Am er G en wi l l per f or m addi t i onal v i sual i nspe ct i ons of t he epox y coa t i ng t hat was appl i ed t o t he ex t er i or sur f ace of t he D r y we l l shel l i n t he sa nd b ed r egi on, such th a t th e c o a te d s u rf a c e s in a ll 1 0 D ryw e ll bay s wi l l have bee n i nspe ct ed a t l east once. I n addi t i on, t he I nser v i ce I nspe ct i on (IS I) P ro g ra m w i l l b e e n h a n c e d to re q u i re i nspe ct i on of 100% of t he epox y coa t i ng Pr i or t o t he per i od of ex t ended o per at i on (com pl et ed dur i ng 2006 r ef uel i ng o u ta g e); t h e n e v e ry ot her r ef uel i ng out age t her eaf t er A P P E ND I X A: COM MI T ME NT S F OR L I CE NS E RE NE W A L OF OCGS C O M M I TM E N T NUMBER I TE M N U M B E R AN D C O M M I TM E N TU F S AR S UP P L E ME NT L OCA T I ON (L R A A P P. A)E NH A NC E ME NT OR I MP L E ME NT A T I ON SCH EDU LE S OUR CE A-23 ev er y 10 y ear s du r i ng t he per i od of ex t ended o per at i on. T hese i nspe ct i ons w il l b e p e rf o rm e d in a c c o rd a n c e w ith ASM E Se c t i o n X I , Su b s e c t i o n I W E.Per f or m ance of t he i nspe ct i ons wi l l be s ta g g e r e d s u c h th a t a t le a s t th r e e b a ys wi l l be ex am i ned ev er y ot her r ef uel i ng out age.N ot e: T he s cope and f r equenc y f or t he i n s p e c ti o n s d e s c ri b e d i n i te m n u m b e r4 (a b o v e) h a s b e e n c h a n g e d to a ll 1 0 b a ys e v e ry o th e r re f u e li n g o u ta g e , in a c c o rd a n c e w ith ite m 2 1 o f th e IW E I n s p e c t i o n P r o g r a m. (5)
A v is u a l e x a m in a tio n o f th e d ryw e ll s h e ll i n t he d r y we l l f l oor i nspe ct i on a ccess t r ench es wi l l be per f or m ed t o as sur e t hat th e d ryw e ll s h e ll re m a in s in ta c t. If d e g ra d a tio n is id e n tifie d , th e d ryw e ll s h e ll c o n d i t i o n w i l l b e e va l u a t e d a n d c o r r e c t i ve act i ons t aken as n eces sar y. I n addi t i on, o n e-t i me u l t r a s o n i c t e s t i n g (UT)m e a s u re m e n ts w i l l b e ta k e n to c o n firm th e a d e q u a c y o f th e s h e ll th ic k n e s s in t hese ar eas. B ey ond t hese exam i nat i ons, Pr i or t o t he per i od of ex t ended o per at i on (com pl et ed dur i ng 2006 r ef uel i ng out age)
A P P E ND I X A: COM MI T ME NT S F OR L I CE NS E RE NE W A L OF OCGS C O M M I TM E N T NUMBER I TE M N U M B E R AN D C O M M I TM E N TU F S AR S UP P L E ME NT L OCA T I ON (L R A A P P. A)E NH A NC E ME NT OR I MP L E ME NT A T I ON SCH EDU LE S OUR CE A-24 t hese sur f aces wi l l ei t her be i nspe ct ed as p a rt o f th e s c o p e o f th e A S M E S e c tio n X I, Subsect i on I W E i nspe ct i on pr ogr am or t hey wi l l be r est or ed t o t he or i gi nal des i gn conf i gur at i on us i ng c oncr et e or ot her s u i ta b l e m a te ri a l to p re v e n t m o i s tu re c o ll e c tio n in th e s e a re a s. N ot e: I t em 5 (abov e) i s s uppl em ent ed by Ite m n u m b e rs 1 6 a n d 2 0 o f th e IW E I n s p e c t i o n P r o g r a m. (6)
T he c oat i ng i nsi de t he t or us wi l l be v is u a ll y i n s p e c te d in a c c o rd a n c e w ith AS M E S ect i on XI , Subsec t i on I W E, per t he Pr ot ect i v e C oat i ngs Pr ogr am. T he s c o p e o f e a c h o f th e s e in s p e c tio n s w il l i ncl ude t he wet t ed ar ea of al l 20 t or us bay s. Shoul d t he c ur r ent t or us c oat i ng sy st em be r epl aced , t he i nspe ct i on f r e q u e n c y a n d s c o p e w i l l , a s a mi n i mu m, m e e t t h e r e q u i r e m e n t s o f ASM E Se c t i o n X I , Su b s e c t i o n I W E. (7)
A m er G en w i l l cond uct U T t hi ckness m easu r em ent s i n t he uppe r r egi ons of t he dr y wel l she l l ev er y ot her r ef uel i ng out age Ev er y ot her r ef uel i ng o u ta g e p rio r to (com pl et ed dur i ng 2006 r ef uel i ng out age) and du r i ng t he per i od of ex t ended o per at i on.Ev er y ot her r ef uel i ng o u ta g e p rio r to (com pl et ed dur i ng 2006 r ef uel i ng Let t er 2130-06-20426 A P P E ND I X A: COM MI T ME NT S F OR L I CE NS E RE NE W A L OF OCGS C O M M I TM E N T NUMBER I TE M N U M B E R AN D C O M M I TM E N TU F S AR S UP P L E ME NT L OCA T I ON (L R A A P P. A)E NH A NC E ME NT OR I MP L E ME NT A T I ON SCH EDU LE S OUR CE A-25 a t th e s a m e lo c a tio n s a s a re c u rre n tly m easu r ed. (8)
T he I W E P r ogr am wi l l be c r edi t ed f or m anagi ng c or r osi on i n t he T or us Vent Li ne and Vent H eader ex pose d t o an In d o o r A ir (E x te rn a l) e n v iro n m e n t. (9)
D ur i ng t he nex t U T i nspe ct i ons t o be per f or m ed on t he dr y wel l san d bed r egi on (re f e re n c e A m e rG e n 4/4/0 6 le tte r to N R C), a n a tte m p t w il l b e m a d e to lo c a te and ev al uat e so m e of t he l ocal l y t hi nned ar eas i dent i f i ed i n t he 1992 i nspe ct i on f ro m th e e x te rio r o f th e d ryw e ll. T h is t est i ng w i l l be p er f or m ed u si ng t he l at est U T m et hodol ogy wi t h ex i st i ng s hel l pai nt i n pl ace. T he U T t hi ckness m easu r em ent s f or t hese l ocal l y t hi nned ar eas m ay be t aken f r om ei t her i nsi de t he dr y wel l or out si de t he dr y wel l (sand bed r egi on) t o l i m i t r adi at i on dos e t o as l ow as re a s o n a b l y a c h i e v a b l e (A L A R A).out age) and du r i ng t he per i od of ex t ended o per at i on Pr i or t o t he per i od of ex t ended o per at i on (com pl et ed dur i ng 2006 r ef uel i ng o u ta g e); t h e n e v e ry ot her r ef uel i ng out age t her eaf t er A P P E ND I X A: COM MI T ME NT S F OR L I CE NS E RE NE W A L OF OCGS C O M M I TM E N T NUMBER I TE M N U M B E R AN D C O M M I TM E N TU F S AR S UP P L E ME NT L OCA T I ON (L R A A P P. A)E NH A NC E ME NT OR I MP L E ME NT A T I ON SCH EDU LE S OUR CE A-26N o te: It e m 9 (a b o v e) is s u p p le m e n te d b y I t em s 14 and 21 of t he I W E I nspe ct i on P r o g r a m. (10)
A m er G en w i l l cond uct U T t hi ckness m easu r em ent s on t he 0.770 i nch t hi ck pl at e at t he j unct i on bet ween t he 0.770 in c h th ic k a n d 1.1 5 4 in c h th ic k p la te s , in t he l ower por t i on of t he s pher i cal r egi on o f th e d ryw e ll s h e ll. T h e s e m e a s u re m e n ts wi l l be t aken at f our l ocat i ons usi ng t he 6"x 6" gr i d. T he s peci f i c l ocat i ons t o be sel ect ed wi l l con si der pr ev i ous oper at i onal ex per i ence (i.e., wi l l be b i a s e d t o w a r d a r e a s t h a t h a ve ex per i ence d co r r osi on or hav e been exposed t o w at er l eaka ge). T hese m e a s u re m e n ts w il l b e p e rf o rm e d p rio r to t he per i od of ex t ended o per at i on and r epeat ed at t he s econ d r ef uel i ng out age a f t e r t h e i n i t i a l i n s p e c t i o n , a t t h e s a me l ocat i on. I f cor r osi on i n t hi s t r ansi t i on ar ea i s gr eat er t han ar eas m oni t or ed i n t he upper dr y wel l , U T i nspe ct i ons i n t he t r ansi t i on ar ea wi l l be per f or m ed on t he sam e f r equenc y as t hose i n t he uppe r d ry w e l l (e v e ry o th e r re fu e l i n g o u ta g e).Pr i or t o t he per i od of ex t ended o per at i on and t wo r ef uel i ng o u ta g e s l a te r.
A P P E ND I X A: COM MI T ME NT S F OR L I CE NS E RE NE W A L OF OCGS C O M M I TM E N T NUMBER I TE M N U M B E R AN D C O M M I TM E N TU F S AR S UP P L E ME NT L OCA T I ON (L R A A P P. A)E NH A NC E ME NT OR I MP L E ME NT A T I ON SCH EDU LE S OUR CE A-27 (11)
A m er G en w i l l cond uct U T t hi ckness m e a s u re m e n ts in th e d ryw e ll s h e ll"knuckl e" ar ea, on t he 0.640 i nch t hi ck pl at e ab ove t he w el d t o t he 2.625 i nch t hi ck pl at e. T hese m easu r em ent s wi l l be t aken at f our l ocat i ons usi ng t he 6"x 6"gr i d. T he s peci f i c l ocat i ons t o be s el ect ed wi l l con si der pr ev i ous oper at i onal e x p e ri e n c e (i.e., w i l l b e b i a s e d to w a rd ar eas t hat hav e ex per i ence d co r r osi on or h a v e b e e n e x p o s e d to w a te r l e a k a g e).T hese m easu r em ent s wi l l be per f or m ed pr i or t o t he per i od of ex t ended o per at i on and r epeat ed at t he s econ d r ef uel i ng out age af t er t he i ni t i al i nspe ct i on, at t he s a m e lo c a tio n. If c o rro s io n in th is t r ansi t i on ar ea i s gr eat er t han ar eas mo n i t o r e d i n t h e u p p e r d r y w e l l , UT i nspe ct i ons i n t he t r ansi t i on ar ea wi l l be per f or m ed on t he s am e f r equenc y as t hose i n t he uppe r dr y wel l (ev er y ot her re fu e l i n g o u ta g e). (1 2)
W h e n th e s a n d b e d re g io n d ryw e ll s h e ll coat i ng i nspe ct i on i s pe r f or m ed (C om m i t m ent 27, I t em s 4 a nd 21), t he seal at t he j unct i on bet ween t he s and bed Pr i or t o t he per i od of ex t ended o per at i on and t wo r ef uel i ng o u ta g e s l a te r.Pr i or t o t he per i od of ex t ended o per at i on (com pl et ed dur i ng 2006 r ef uel i ng o u ta g e); t h e n e v e ry A P P E ND I X A: COM MI T ME NT S F OR L I CE NS E RE NE W A L OF OCGS C O M M I TM E N T NUMBER I TE M N U M B E R AN D C O M M I TM E N TU F S AR S UP P L E ME NT L OCA T I ON (L R A A P P. A)E NH A NC E ME NT OR I MP L E ME NT A T I ON SCH EDU LE S OUR CE A-28 r egi on c oncr et e and t he em bedded dr y wel l she l l wi l l be i nspe ct ed per t he P r o t e c t i v e C o a t i n g s P r o g r a m.N ot e: T he f r equenc y f or t he i nspe ct i ons desc r i bed i n I t em 12 (abov e) has been chan ged t o ev er y ot her r ef uel i ng out age, in a c c o rd a n c e w ith Ite m 2 1 o f th e IW E I nspe ct i on Pr ogr am (1 3)
T h e re a c to r c a v ity c o n c re te tro u g h d ra in wi l l be v er i f i ed t o be c l ear f r om bl ock age once per r ef uel i ng c y cl e. Any i dent i f i ed i ss ues wi l l be add r ess ed v i a t he cor r ect i v e act i on p r ocess. (14)
U T t hi ck ness m easu r em ent s wi l l be t aken f r om out si de t he dr y wel l i n t he s and bed r egi on dur i ng t he 2008 r ef uel i ng out age on t he l ocal l y t hi nned ar eas ex am i ned dur i ng t he O ct ober 2006 r ef uel i ng out age.T he l ocal l y t hi nned ar eas ar e di st r i but ed bot h v er t i cal l y and ar ound t he per i m et er of t he dr y wel l i n al l t en bay s s uch t hat p o te n tia l c o rro s io n o f th e d ryw e ll s h e ll woul d be de t ect ed.ot her r ef uel i ng o u ta g e th e re a fte r.O nce per r ef uel i ng cy cl e.D ur i ng t he 2008 r ef uel i ng out age and ev er y ot her r ef uel i ng out age t her eaf t er A P P E ND I X A: COM MI T ME NT S F OR L I CE NS E RE NE W A L OF OCGS C O M M I TM E N T NUMBER I TE M N U M B E R AN D C O M M I TM E N TU F S AR S UP P L E ME NT L OCA T I ON (L R A A P P. A)E NH A NC E ME NT OR I MP L E ME NT A T I ON SCH EDU LE S OUR CE A-29N ot e: T he f r equenc y f or t he i nspe ct i ons desc r i bed i n I t em 14 (abov e) has been c h a n g e to e v e ry o th e r re f u e li n g o u ta g e , in a c c o rd a n c e w ith Ite m 2 1 o f th e IW E I n s p e c t i o n P r o g r a m. (1 5)
S t a r t i n g i n 2 0 1 0 , d r y w e l l s h e l l UT t hi ck ness m easu r em ent s wi l l be t aken f r om out si de t he dr y wel l i n t he s and bed r egi on i n t wo bay s pe r out age, suc h t hat i nspe ct i ons wi l l be per f or m ed i n al l 10 ba y s wi t hi n a 10-y ea r pe r i od. The t wo bay s wi t h t he m ost l ocal l y t hi nned ar eas (bay #1 and bay # 13) wi l l be i nspe ct ed in 2 0 1 0. If th e U T e x a m in a tio n s yi e ld u n a c c e p ta b le re s u lts , th e n th e lo c a ll y t hi nned ar eas i n al l 10 bay s wi l l be i nspe ct ed i n t he r ef uel i ng out age t hat t he unac cept abl e r esul t s ar e I dent i f i ed.N ot e: T he s cope and f r equenc y f or t he i nspe ct i ons desc r i bed i n I t em 15 (abov e)h a v e b e e n c h a n g e d to a l l 1 0 b a y s e v e ry ot her r ef uel i ng o ut age , i n acco r dan ce wi t h I t em 21 of t he I W E I nspe ct i on P r o g r a m.Al l 10 bay s wi l l be i nspe ct ed dur i ng t he 2008 r ef uel i ng o u ta g e a n d e v e ry ot her r ef uel i ng o u ta g e th e re a fte r.D ur i ng t he 2008 A P P E ND I X A: COM MI T ME NT S F OR L I CE NS E RE NE W A L OF OCGS C O M M I TM E N T NUMBER I TE M N U M B E R AN D C O M M I TM E N TU F S AR S UP P L E ME NT L OCA T I ON (L R A A P P. A)E NH A NC E ME NT OR I MP L E ME NT A T I ON SCH EDU LE S OUR CE A-30 (1 6)
P e rf o rm v is u a l i n s p e c tio n s o f th e d ryw e ll shel l i nsi de t he t r ench es i n bay # 5 and b a y # 1 7 a n d ta k e U T m e a s u re m e n ts i nsi de t hese t r ench es I n 2008 at t he sam e l ocat i ons ex am i ned i n 2006.R e p e a t (b o th th e U T a n d v is u a l)i nspe ct i ons at r ef uel i ng out ages dur i ng t he per i od of ex t ended o per at i on unt i l t he t r ench es a r e r est or ed t o t he or i gi nal desi gn c onf i gur at i on us i ng c oncr et e or ot her sui t abl e m at er i al t o pr ev ent m oi st ur e col l ect i on i n t hese ar eas.N ot e: I t em 16 (abov e) i s s uppl em ent ed by I t em 20 of t he I W E I nspe ct i on Pr ogr am (1 7)
P e rfo rm v i s u a l i n s p e c ti o n o f th e m o i s tu re bar r i er bet ween t he dr y wel l she l l and t he conc r et e f l oor cur b, i nst al l ed i nsi de t he dr y wel l dur i ng t he O ct ober 2006 r ef uel i ng o u t a g e , i n a c c o r d a n c e w i t h ASM E Sect i on XI , Subsec t i on I W E dur i ng t he per i od of ex t ended o per at i on.(1 8)
A m e rG e n w il l p e rf o rm a 3-D f in ite e l e m e n t s tru c tu ra l a n a l y s i s o f th e p ri m a ry r ef uel i ng out age and subs equent r ef uel i ng o u ta g e s u n til t r ench es a r e r est or ed t o or i gi nal conf i gur at i on.In a c c o rd a n c e w ith A S M E S e c tio n X I, Su b s e c t i o n I W E.Pr i or t o t he per i od of ex t ended o per at i on A P P E ND I X A: COM MI T ME NT S F OR L I CE NS E RE NE W A L OF OCGS C O M M I TM E N T NUMBER I TE M N U M B E R AN D C O M M I TM E N TU F S AR S UP P L E ME NT L OCA T I ON (L R A A P P. A)E NH A NC E ME NT OR I MP L E ME NT A T I ON SCH EDU LE S OUR CE A-31 c o n ta i n m e n t d ry w e l l s h e l l u s i n g m o d e rn m e th o d s a n d c u rre n t d ryw e ll s h e ll t hi ck ness dat a t o bet t er quant i f y t he m ar gi n t hat ex i st s ab ov e t he Code r equi r ed m i ni m um f or buc kl i ng. T he a n a ly s is w il l i n c lu d e s e n s iti v ity s tu d ie s to det er m i ne t he d egr ee t o w hi ch unce r t ai nt i es i n t he s i z e of t hi nned ar eas a f f e c t C o d e m a rg in s. If th e a n a ly s is det er m i nes t hat t he dr y wel l she l l does not me e t r e q u i r e d t h i c k n e s s v a l u e s , t h e NR C wi l l be not i f i ed i n ac cor danc e wi t h 10 C FR 50 r equ i r em ent s.(19)
Am er G en wi l l per f or m an eng i neer i ng s t u d y t o i n ve s t i g a t e c o s t-e ff e c t i ve re p la c e m e n t o r re p a ir o p tio n s to e li m in a te or r educ e r eact or cav i t y l i ner l eaka ge. (20)
Am er G en i s c om m i t t ed t o per f or m v i sual a n d U T in s p e c tio n s o f th e d ryw e ll s h e ll in t he i nspe ct i on t r ench es i n dr y we l l bay s 5 and 17 dur i ng t he O y st er C r eek 2008 r ef uel i ng out age (see i t em 16 of Am er G en's I W E P r ogr am (com m i t m ent 2 7), m a d e i n i ts l e tt e r 2 1 3 0-0 6-2 0 4 2 6).Am er G en wi l l ex t end t hi s c om m i t m ent Pr i or t o t he per i od of ex t ended o per at i on A P P E ND I X A: COM MI T ME NT S F OR L I CE NS E RE NE W A L OF OCGS C O M M I TM E N T NUMBER I TE M N U M B E R AN D C O M M I TM E N TU F S AR S UP P L E ME NT L OCA T I ON (L R A A P P. A)E NH A NC E ME NT OR I MP L E ME NT A T I ON SCH EDU LE S OUR CE A-32 and al so p er f or m t hese i nspe ct i ons d u rin g th e 2 0 1 0 re f u e li n g o u ta g e. In ad di t i on , Am er G en wi l l m on i t or t he t wo t r ench es f or t he pr esen ce o f wat er dur i ng r e f u e l i n g o u t a g e s. V i s u a l a n d UT i nspe ct i ons of t he s hel l wi t hi n t he t r ench es wi l l con t i nue t o be pe r f or m ed unt i l no wat er i s i dent i f i ed i n t he t r ench es f or t wo con sec ut i v e r ef uel i ng out ages , at whi ch t i m e t he t r ench es wi l l be r est or ed to th e ir o rig in a l d e s ig n c o n f ig u ra tio n (e.g., r ef i l l ed w i t h con cr et e) t o m i ni m i z e t he r i sk of f ut ur e co r r osi on.(21)
Per f or m t he f ul l sc ope of dr y wel l san d bed r egi on i nspe ct i ons pr i or t o t he per i od o f e x te n d e d o p e ra ti o n a n d th e n e v e ry o th e r re f u e li n g o u ta g e th e re a f te r. T h e f u ll scope i s def i ned as:
- U T m e a s u re m e n ts f ro m in s id e th e d ryw e ll ( I t em 1)
- Vi sual i nspe ct i ons of t he dr y wel l ex t er nal shel l epox y coa t i ng i n al l 10 bay s ( I t em 4)D ur i ng t he 2008 r ef uel i ng out age and ev er y ot her r ef uel i ng o u ta g e th e re a f te r. If t he anal y si s be i ng per f or m ed unde r I t e m 1 8 a b o ve est abl i shes i ncr ease d m ar gi n, or i f ongoi ng i nspe ct i ons cont i nue t o dem onst r at e t hat dr y wel l cor r osi on has A P P E ND I X A: COM MI T ME NT S F OR L I CE NS E RE NE W A L OF OCGS C O M M I TM E N T NUMBER I TE M N U M B E R AN D C O M M I TM E N TU F S AR S UP P L E ME NT L OCA T I ON (L R A A P P. A)E NH A NC E ME NT OR I MP L E ME NT A T I ON SCH EDU LE S OUR CE A-33
- I nspe ct i on of t he s eal at t he j unct i on b e tw e e n th e s a n d b e d re g io n c o n c re te and t he em bedded dr y wel l she l l ( I t em 12)
- U T m easu r em ent s at t he ex t er nal ar eas i nspe ct ed i n 2006 (I t em s 9 a nd 14)b e e n s u f f ic ie n tly ar r est ed, t he per i od bet ween i nspe ct i ons m ay abl e i ncr ease d to m i n i m i ze per sonn el r adi at i on ex posu r e.2 8)
ASM E S e c tio n X I, Subsect i on IW F Ex i st i ng pr ogr am i s c r edi t ed. T he s cope of t he pr ogr am wi l l be enh ance d t o i ncl ude add i t i onal M C sup por t s, and r equi r e i nspe ct i on of t he u n d e rw a te r s u p p o rts f o r lo s s o f m a te ria l d u e to cor r osi on and l oss of m echa ni cal f unct i on and l oss of pr el oad on bol t i ng by i nspe ct i ng f or m i ssi ng, det ache d, or l oose ned bol t s.A.1.28 Pr i or t o t he per i od of ex t ended o per at i on.Sect i on B.1.28 2 9) 1 0 CF R Par t 50, A p p e n d i x J Ex i st i ng pr ogr am i s c r edi t ed.
A.1.29 O ngoi ng Sect i on B.1.29 3 0)
M a s o n ry W a ll Pr ogr am E x is tin g p ro g ra m is c re d ite d. T h e M a s o n ry W a ll Pr ogr am i s pa r t of t he St r uct ur es Moni t or i ng P r o g r a m.A.1.30 O ngoi ng Sect i on B.1.30 A P P E ND I X A: COM MI T ME NT S F OR L I CE NS E RE NE W A L OF OCGS C O M M I TM E N T NUMBER I TE M N U M B E R AN D C O M M I TM E N TU F S AR S UP P L E ME NT L OCA T I ON (L R A A P P. A)E NH A NC E ME NT OR I MP L E ME NT A T I ON SCH EDU LE S OUR CE A-40 e v a lu a tio n w il l b e p e rf o rm e d to d e te rm in e if i dent i f i ed degr adat i on war r ant s m or e f r equent i nspe ct i on o r cor r ect i v e act i ons.3 3)
P r o t e c t i ve C oat i ng M oni t or i ng and M ai nt ena nce P r o g r a m Ex i st i ng pr ogr am i s c r edi t ed. T he O y st er C r eek P r ot ect i v e C oat i ng M oni t or i ng a nd M ai nt ena nce Pr ogr am pr ov i des f or agi ng m anagem ent of S e rv i c e L e v e l I c o a ti n g s i n s i d e th e p ri m a ry cont ai nm ent and Ser v i ce L ev el I I coa t i ngs f or t he ex t er nal dr y wel l she l l i n t he ar ea of t he s and bed r egi on. T he pr ogr am wi l l be enh ance d t o i ncl ude: (1)
T he i nspe ct i on of Ser v i ce L ev el I and S e rv i c e L e v e l II p ro te c ti v e c o a ti n g s th a t a re cr edi t ed f or m i t i gat i ng c or r osi on on i nt er i or sur f aces of t he T or us s hel l and v ent sy st em , a n d , o n e x te rio r s u rf a c e s o f th e D ryw e ll s h e ll i n t he ar ea of t he s andbed r egi on, wi l l be c o n s is te n t w ith A S M E S e c tio n X I, S ubse ct i on I W E r equ i r em ent s.(2)
A d d i t i o n a l vi s u a l i n s p e c t i o n s o f t h e e p o xy coat i ng t hat was a ppl i ed t o t he ex t er i or sur f ace of t he dr y wel l she l l i n t he s and bed re g io n , s u c h th a t th e c o a te d s u rf a c e s in a ll 10 dr y wel l bay s wi l l hav e been i nspe ct ed at l east onc e pr i or t o ent er i ng t he per i od of ex t ended o per at i on.A.1.33 Pr i or t o t he per i od of ex t ended o per at i on.Sect i on B.1.33 Let t er 2130-06-20354 A P P E ND I X A: COM MI T ME NT S F OR L I CE NS E RE NE W A L OF OCGS C O M M I TM E N T NUMBER I TE M N U M B E R AN D C O M M I TM E N TU F S AR S UP P L E ME NT L OCA T I ON (L R A A P P. A)E NH A NC E ME NT OR I MP L E ME NT A T I ON SCH EDU LE S OUR CE A-41 (3)
T he i nspe ct i on of 100% of t he s andbed r egi on epox y coa t i ng ev er y 10 y ear s du r i ng t he per i od of ex t ended o per at i on.I nspe ct i ons wi l l be s t agger ed s uch t hat at l e a s t t h re e b a y s w i l l b e e x a m i n e d e v e ry ot her r ef uel i ng out age.(4)
T h e in s p e c tio n o f a ll 2 0 to ru s b a ys a t a f r equenc y of ev er y ot her r ef uel i ng out age f or t he c ur r ent coa t i ng s y st em. Shoul d t he cur r ent coa t i ng s y st em be r epl aced , t he i nspe ct i on f r equenc y and s cope wi l l be r e-eval uat ed. I nspe ct i on sco pe w i l l , as a m i n i m u m , mee t t h e r e q u i r e m e n t s o f ASM E Se c t i o n X I , Su b s e c t i o n I W E.N ot e: T he s cope and f r equenc y f or t he i nspe ct i ons desc r i bed i n I t em 4 (abov e) has been chan ged t o al l 10 bay s ev er y ot her r ef uel i ng o u ta g e , in a c c o rd a n c e w ith Ite m 2 1 o f th e IW E I n s p e c t i o n P r o g r a m.34)
El ect r i cal C abl es a nd C onnec t i ons N o t S u b je c t to 10 CF R 50.49 Env i r onm ent al P ro g ra m is n e w. T h e p ro g ra m w il l b e u s e d to m anage a gi ng of non-EQ cab l es a nd conn ect i ons dur i ng t he per i od of ex t ended o p e ra tio n. A re p re s e n ta tiv e s a m p le o f a c c e s s ib le cabl es an d con nect i ons l ocat ed i n ad v er se l ocal i z ed env i r onm ent s wi l l be v i sual l y i nspe ct ed A.1.34 Pr i or t o t he per i od of ex t ended o per at i on.Sect i on B.1.34 Staff Exhibit 2
Subsection IWE Excerpts SUBSECTION IWE REQUIREMENTS FOR CLASS MC AND METALLIC LINERS OF CLASS CC COMPONENTS OF LIGHT-WATER COOLED PLANTS IWE-1000 IWE- I IUO IWE- I200 IWE-I210 IWE-I 220 IWE-I 230 IWE-I231 WE-I 232 IWE- I 240 WE-1 241 WE-1 242 Scope and Responsibility
.................................................
215 Scope ..................................................................
215 Components Subject lo Examination
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215 Examination Requirements
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215 Components Exempted From Examination
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.. ...... 215 Accessibility for Examination
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215 Accessible Surface Areas .................................................
215 Inaccessible Surface Areas ..............................................
215 Surface Areas Requiring Augmented Examination
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216 Examination Surface Areas ................................................
216 Identification of Examination Surface Areas ..................................
216 Examination and Inspection
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217 Preservice Examination
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217 Inspection Schedule
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217 Inspection Rogram .......................................................
217 Inspection Rogram A ....................................................
217 Inspection Program B ..................................................
218 Successive Inspections
....................................................
218 Additional Examinations
..................................................
218 Examination and Pressure Test Requirements
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218 Condition of Surface to Be Examined .......................................
219 Acceptance Standards
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228 Evaluation of Nondestructive Examination Results
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228 Preservice Examinations
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228 General ................................................................
228 Acceptance
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228 Repairs and Reexaminations
...............................................
228 Review by Authorities
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228 Inservice Nondestructive Examinations
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228 General ................................................................
228 Acceptance
..............................................................
228 Acceptance by Examination
...............................................
228 Acceptance by Repair ....................................................
Acceptance by Replacement
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Acceptance by EvaIuation
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Repairs and Reexaminations Review by Authorities
....................................................
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I~iservice Visual Examinations
................................................ Supplemental Examinations
...............................................................
Standards Acceptance Standards
.....................................................
Acceptability
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Acceptance Standards Standards for Examination Category E.A. Containment Surfaces ................
Visual Examinations - General ............................................
VT-3 Vi'sual Examinations on Coated Areas
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VT-3 Visual Examinations on Noncoated Areas
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Standards for Examination Category E.B. Pressure-Retaining Welds .............
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VT-I Visual Examinations on Coated Areas VT-I Visual Examinations on Noncoated Areas
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Standards for Examination Category E.C. Co~itaininent Surfaces Requiring
............................................... Augmented Examinations VT-I Visual Examinations on Coated Areas
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VT-I Visual Examinations on Noncoated Areas
..............................
................................................... Ultrasonic Examination Standards for Examination Category E.D. Seals. Gaskets. and Moisture Barriers ..............................................................
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VT-3 Visual Examinations Standards for Examination Category E.F. Pressure Retaining Dissimilar Metal Welds
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Surface Examinations
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Standards for Examination Category E.G. Pressure Retaining Bolting ......................................................
Visual Examinations
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Bolt Torque or Bolt Tension IWE-4000 Repair Procedures
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232 IWE-4 100 Scope ..................................................................
232 System Pressure Tests
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233 System Test Requirements
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233 General ................................................................
233 Tests Following Repair . Modification.
or Replacement
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233 Leakage Test
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233 Deferral of Leakage Tests
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233 Visual Examination
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233 Corrective Measures
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233 IWE-7000 Replacements
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234 WE-7 100 General Requirements
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234 Figures ...................................................
IWE-2500-1 Dissimilar Metal Welds 219 ..........................
....... 1WE-2500-2 Examination Areas for Moisture Barriers .. 220 Tables IWE-14 1 1 . 1 Inspection Program A ....................................................
218 ....................................................
IWE-24 12-1 Inspecrion Program B 218 ...................................................
IWE-2500-I Examination Categories 221 .....................................................
IWE-34 10- I Acceptance Standards 230 ARTICLE IWE-1000 SCOPE AND RESPONSIBILITY IWE-1100 SCOPE to the containment vessel. These components shall be examined in accordance with the rules bf IWB or IWC, This Subsection provides the rules and requirements as appropriate to the classification defined by the De- for inservice inspection, repair, and replacement of sign Specifications.
Class MC pressure retaining components and their in-tegral attachments, and of metallicshell and penetration liners of Class CC pressure retaining components and their integral attachments in light-water cooled plants.
IWE-1230 ACCESSIBILITY FOR EXAMINATION IWE-1200 COMPONENTS SUBJECT TO EXAMINATION IWE-1210 EXAMINATION REQUIREMENTS The examination requirements of this Subsection shall apply to Class MC pressure retaining components and their integral attachments and to metalIic shell and penetration liners of Class CC pressure retaining com- ponents and their integral attachments. These exami- nations shall apply to surface areas, including welds and base metal.
IWE-123 1 Accessible Surface Areas (a) As a minimum, the following portions of Class MC containment vessels, parts, and appurtenances and Class CC metallic shell and penetration liners shall re- main accessible for either direct or remote visual ex- amination, from at least one side of the vessel, for the life of the plant: (1) openings and penetrations; (2) structural discontinuities; (3) single-welded butt joints from the weld side; (4) 80% of the surface area defined in Table IWE- 2500- 1, Examination Category E-A; and (5) surface areas identified in IWE-1240. (b) The requirements of IWE-1232 shall be met 1WE-1220 when accessibility for visual examination is not from EXAMINATION the outside surface. The following components (or parts of components) are exempted from the examination requirements of IWE-1232 Inaccessible Surface Areas IWE-2000: (a) vessels, parts, and appurtenances that are outside the boundaries of the containment as defined in the Design Specifications; (b) embedded or inaccessible portions of contain-ment vessels, parts, and appurtenances that met the re- quirements of the original Construction Code; (c) portions of containment vessels, parts, and ap; purtenances that become embedded or inaccessible as a result of vessel repair or replacement if the conditions of IWE-1232 and IWE-5220 are met; (d) piping, pumps, and valves that are part of the containment system, or which penetrate or are attached (a) Portions of Class MC containment vessels, parts, and appurtenances that are embedded in concrete or otherwise made inaccessible during construction of the vessel or as a result of vessel repair, modification, or replacement are exempted from examination, provided: (I) no openings or penetrations are embedded in the concrete; (2) all welded joints that are inaccessible for ex- amination are double buttwelded and are fully radio- graphed and, prior to being covered, are tested for leak tightness using a gas medium test, such as Halide Leak Detector Test; 1992 SECTION XI - DIVISION 1 (3) all weld joints that are not double butt welded remain accessible for examination from the weld side; and (4) the vessel is leak rate tested after completion of construction, repair, or replacement to the leak rate requirements of the Design Specifications. (b) Portions of Class CC metallic shell and penetra- tion liners that are embedded in concrete or otherwise made inaccessible during construction or as a result of repair or replacement are exempted from examination, provided: (I) all welded joints that are inaccessible for ex- amination are examined in accordance with CC-5520 and, prior to being covered or otherwise obstructed by adjacent structures, components, parts, or appurte- nances, are tested for leak tightness in accordance with CC-5536; and (2) the containment is leak rate tested after com- pletion of construction, repair, or replacement to the leak rate requirements of the Design Specifications.
IWE-1240 SURFACE AREAS REQUIRING AUGMENTED EXAMINATION (a) interior and exterior containment surface areas that are subject tc accelerated corrosion with no or min- imal corrosion allowance or areas where the absence or repeated loss of protective coatings has resulted in substan~ial corrosion and pitting. Typical loca~ionb of such areas are those exposed to standing water, re- peated wetting and drying, persistent leakage, and those with geometries that permit water accumulation, condensation, and microbiological attack.
Such areas may include penetration sleeves, surfaces wetted during refueling, concrete-to-steel shell or liner interfaces, embedment zones, leak chase channels, drain areas, or sump liners. (b) interior and exterior containment surface areas that are subject to excessive wear from abrasion or ero- sion that causes a loss of protective coatings, defor-mation, or material loss. Typical locations of such areas are those subject to substantial traffic, sliding pads or supports, pins or clevises, shear lugs, seismic restraints, surfaces exposed to water jets from testing operations or safety relief valve discharges, and areas that experience wear from frequent vibrations. IWE-1242 Identification of Examination Surface Areas IWE-1211 Examination Surface Areas Surface areas requiring augmented examination shall Surface areas likely to experience accelerated deg- be determined in accordance with IWE-1241, and shall radation and aging require the augmented examinations be identified in the Owner's Inspection Program.
identified in Table IWE-2500-1, Examination Category Examination methods shall be in accordance with E-C. Such areas include the following:
IWE-2500(c).
ARTICLE IWE-2000 EXAMINATION AND INSPECTION IWE-2200 PRESERVICE EXAMINATION (3) When a system leakage test is required by (a) Examinations listed in Table IWE-2500-1 shall be completed prior to initial plant startup. These pre- service examinations shall include the pressure retain-ing portions of components not exempted by IWE- 1220. (b) When visual examinations are required, these ex- aminations shall be performed in accordance with IWE- 2600, following the completion of the pressure test re- quired by the construction Code and after application of protective coatings (e.g., paint) when such coatings are required. (c) When surface examinations are required by Ta- ble IWE-2500-1, shop or field examinations in accor- dance with NE-5000 for Class MC or CC-5500 for Class CC may serve in lieu of the on-site preservice examinations, provided: (I) the examinations are conducted by the same method with equipment and techniques equivalent to those that are expected to be employed for subsequent inservice examinations; (2) the shop or field examination records are, or can be, documented and identified in a form consistent with those required in IWA-6000; and (3) the examinations are performed after the pres- sure test required by the Construction Code has been completed. (d) When a vessel, liner, or a portion thereof is re- paired or replaced during the service lifetime of a plant, the preservice examination requirements for the vessel repair or replacement shall be met. (I) When the repair or replacement is performed while the plant is not in service, the preservice ex- amination shall be performed prior to the resumption of service. (2) When the repair or replacement is performed while the plant is in service, the preservice examination may be deferred to the next scheduled plant outage, provided nondestructive examination in accordance with the approved repair program is performed.
1WE-5220, the preservice examination may be per- formed either prior to or following the test. (e) Welds made as part of a repair or a replacement program shall be examined in accordance with the re- quirements of IWA-4000, except that for welds joining Class MC or Class CC components to items designed, constructed, and installed to the requirements of Sec- tion 111, Class 1, t, or 3, the examination requirements of IWB-2000, IWC-2000, or IWD-2000, as applicable, shall apply. If) Preservice examination for a repair or replace-ment may be conducted prior to installation provided:
(1) the examination is performed after the pressure test required by the Construction Code has been com-pleted; (2) the examination is conducted under conditions and with equipment and techniques equivalent to those that are expected to be employed for subsequent in- service examinations; and (3) the shop or field examination records are, or can be, documented and identified in a form consistent with that required by IWA-6000.
(5) When paint or coatings are reapplied, the con- dition of the new paint or coating shall be documented in the preservice examination records. IWE-2400 INSPECTION SCHEDULE IWE-2410 INSPECTION PROGRAM Inservice examinations and system pressure tests may be performed during plant outages such as re- fueling shutdowns or maintenance shutdowns.
The re- quirements of either Inspection Program A or Inspec-tion Program B shall be met.
IWE-2411 Inspection Program A (a) With the exception of the examinations that may be deferred until the end of an inspection interval, as 1992 SECTION XI - DIVISION 1 IWE-2500 TABLE IWE-2411-1 INSPECTION PROGRAM A Inspection Period, Minimum Maximum Inspection Calendar Years of Exaniinations Examinations Interval Plant Service Completed, % Credited, % 1st 3 100 100 TABLE IWE-2412-1 INSPECTION PROGRAM B lnspection Period, Calendar Years of Minimum Maximum lnspection Plant Service, Examinations Examinations Interval Within the Interval Completed, % Credited, % 1st 3 16 34 7 50 67 10 100 100 3rd 13 16 34 Successive 3 16 34 17 40 50 7 50 67 20 66 75 10 100 100 2 3 100 100 specified in Table IWE-2500-1,. the required exami- nations shall be completed during each successive in- spection interval, in accordance with Table IWE-2411-
- 1. Following completion of Program A after 40 years, successive inspection intervals shall follow the 10 year inspection interval of Program B. (b) The inspection period specified in IWE-24 1 1 (a) may be decreased or extended by as much as 1 year to enable an inspection to coincide with a plant outage, within the limitations of IWA-2430(c).
IWE-2412 Inspection Program B (a) With the exception of the examinations that may be deferred until the end of an inspection interval, as specified in Table IWE-2500-1, the required exami- nations shall be completed during each successive in- spection interval, in accordance with Table IWE-2412-1. (b) The inspection period specified in IWE-2412(a) may be decreased or extended by as much as 1 year to enable an inspection to coincide with a plant outage, within the limitations of IWA-2430(d).
accordance with IWE-3000, and the component is found to be acceptable for continued service, the areas containing such flaws, degradation, or repairs shall be reexamined during the next inspection period listed in the schedule of the inspection program of IWE-2411 or IWE-2412, in accordance with Table IWE-2500-1, Examination Category E-C, (c) When the reexaminations required by IWE- 2420(b) reveal that the flaws, areas of degradation, or repairs remain essentially unchanged for three consec- utive inspection periods, the areas containing such flaws, degradation, or repairs no longer require aug-mented examination in accordance with Table WE- 2500- 1, Examination Category E-C. IWE-2430 ADDITIONAL EXAMINATIONS (a) Examinations performed during any one inspec- tion that reveal flaws or areas of degradation exceeding the acceptance standards of Table IWE-3410-1 shall be extended to include an additional number of exarni- nations within the same category approximately equal to the initial number of examinations during the in- spection. (b) When additional flaws or areas of degradation that exceed the acceptance standards of Table IWE- 3410-1 are revealed, all of the remaining examinations within the same category shall be performed to the ex- tent specified in Table IWE-2500-1 for the inspection interval. IWE-2420 SUCCESSIVE INSPECTIONS (a) The sequence of component examinations estab- lished during the first inspection interval shall be re- IWE-2500 EXAMINATION AND PRESSURE peated during each successive inspection interval, to TEST REQUIREMENTS the extent practical. (a) The method of examination for the components, (b) When component examination results require parts, and items (e.g., seals, gaskets, and bolts) of the evaluation of flaws, areas of degradation, or repairs in pressure retaining boundaries shall comply with those REQUIREbIENTS FOR CLASS MC COMPONENTS 1WE-2600 Surface Areas A - B and C - D FIG. WE-2500-1 DlSSIlJlILAR METAL WELDS tabulated in Table IWE-2500-I, except where alternate examination methods are used that meet the require- ments of IWA-2240. (b) When paint or coatings are to be removed, the paint or coatings shall be visually examined in accor- dance with Table IWE-2500-1 prior to removal. (c) Examination methods for surface areas for aug- mented examination in IWE-1242 shall comply with the following criteria. (I) Surface mas accessible from both sides shall be visually examined using a VT-I visual examination method. (2) Surface areas accessible from one side only shall be examined for wall thinnirlg using an ultrasonic thickness ineasurement method in accordance with Sec- tion V, T-544. (3) When ultrasonic thickness measurements are performed, one foot square grids shall be used. The number and location of the grids shall be determined by the Owner.
(4) Ultrasonic measurements shall be used to de- termine the minimum wall thickness within each grid.
The location of the minimum wall thickness shall be marked such that periodic reexamination of that loca- tion can be performed in accordance with the require- ments of Table 1WE-2500-1, Examination Category E-C. IWE-2600 CONDITION OF SURFACE TO BE EXAMINED (a) When a containment vessel or liner is painted or coated to protect surfaces from corrosion, presemice and inservice visual examinations shall be performed without the removal of the paint or coating. (b) When removal of paint or coating is required, it shall be removed in a manner that will not reduce the base metal or weld thickness below the design thick- ness. Reapplied paint and coating systems shall be compatible with the existing system, and shall be ex- amined in accordance with IWE-2200(g).
Fig. 1WE-2500-2 Examination External concrete-to interface moisture 1992 SECTION XI - DIVISION I Pressure retaining metal containment shell or liner Examination area C-D Internal concrete-to-metal interface moisture barrier Embedded shell or liner FIG. IWE-2500-2 EXAMINATION AREAS FOR MOISTURE BARRlERS TABLE IW E-2500-1 (CONT'D) EXAMINATION CATEGORIES t I Item No. NOTES: (1) Exar (2) Exar arou Parts Examined Containment Vessel Pressure Retaining Boundary Accessible Surface area^^^^,^
Accessible Surface area^^.^,^ Vent System Accessible Surface EXAMINATION CATEGORY E-A, CONTAINMENT SURFACES Extent and Frequency of Examination I Examination1 Requirements/
Examination General Visual7 Visual, VT-3 Visual, VT-3 Acceptance Standard Inspection Successive 100% Prior to each Type A tests 100% End. of interval 100% End of interval Prior to each Type A tests 100% End of interval 100% End of interval ination may be made from either the inside or outside surface. ination shall include structures that are parts of reinforcing structure, such as stiffening rlngs, manhole frames, and reinforcement d openings.
(3) Not including surface areas that are submerged or insulated.
(4) lncludlng the wetted surfaces of submerged areas and the portions of insulated surface areas that are necessary to meet the requirements of IWE-l231(a)(4).
(5) Examination shall include the attachment welds between structural attachments and the pressure retaining boundary or reinforcing structure, except for nonstructural and temporary attachments as defined in N E-4435 and minor permanent attachments as defined in CC-4543.4.
Examination shall include the weld metal and the base metal for '/, In. beyond the edge of the weld. (6) Includes flow channeling devices within containment vessels. (7) Refer to IWE-3510.1 for General Visual examination method requirements.
(8) Refer to IWE-5220 for test requirements.
(9) Deferral of inspection is not permissible In the 4th and successive inspection intervals.
TABLE IWE-2500-1 (CONT'D) EXAMINATION CATEGORIES EXAMINATION CATEGORY E-0, PRESSURE RETAINING WELDS Item No. Parts Examined Containment Penetration weld^^,^
Longltudlnal Clrcumferentlal Flued Head and Bellows Seal Circumferential Welds Joined to the Penetration Flange Welds (Category CIb Noule-to-Shell Welds (Category D)b Examination Requirements1 Fig. No. Examination Method Visual, VT-1 Vlsual, VT-1 Visual, VT-1 Acceptance Standard Extent and Frequ 1st Inspection Interval 25% of the total number of welds1.z 25% of the total number of weldsl.2 25% of the total number of weldsl.2 NOTES: (1) Examination shall include the weld metal and the base metal for '/, In. beyond the edge of the weld. (2) Welds shall be randomly selected throughout the containment and representatlve of the type of welds described by each item number. (3) Examination shall Include welds made In accordance wlth Section 111, Class MC, Including those Class MC welds shown in Figs. NE-1120-1 and NE-1132-1.
(4) Different welds shall be selected for examination each lnspectlon Interval.
(5) Includes only those welds subject to cyclic loads and thermal stress durlng normal plant operation.
(6) Welded joint categories are as defined In NE-3351 for Class MC and CC-3840 for Class CC. (7) Deferral of inspection is not permissible in the 4th and successive lnspectlon intervals.
icy of Examination Successive Inspection Intervals4 25% of the total number of 25% of the total number of welds1J 25% of the total number of weldsl.2 Deferral of Inspection to End of Interval' Permissible Permissible Permissible TABLE IWE-2500-1 (CONT'D) EXAMINATION CATEGORIES Item No. E4.10 E4.11 E4.12 NOTES: (1) Containment surface areas requiring augmented examination are those identified In IWE-1240.
(2) The extent of examination shall be 100% for each inspection period until the areas examined remain esser~tiaily unchanged for three consecutive Inspection periods. Such areas no longer require augmented examination in accordance with IWE-2420(c).
(3) Deferral of inspection is not permissible in the 4th and successive inspection intervals.
EXAMINATION Parts Examined Containment Surface Areas Visible Surfaces Surface Area Grid, Minimum Wall Thickness Locatlon CATEGORY E-C, Examination Requirements1 Fig. No. Deferral of Inspection to End of Interval3 blot Permissible blot Permissible CONTAINMENT SURFACES Examination Method Visual, VT-1 Volumetric AUGMENTED EXAMINATION REQUIRING Acceptance Standard IWE-3512.1 IWE-3512.2 IWE-3512.3 Extent and Frequency 1st Inspection Interval 100% of Surface Areas ldentlfied by WE-1242l 100% of Minimum Wall Thickness Locations during each Inspection Period, established in accordance with IWE-2500(~)(3)~
and IWE-2500(~)(4)'
of Examination Successive Inspection Intervals 100% of Surface Areas Identified by IWE-1242' 100% of Minimum Wall Thickness Locations during each Inspection Period, established in accordance with IWE-2500(~)(3)~
and IWE-2500(~)(4)'
TABLE IWE-2500-1 (C EXAMINATION CATE( EXAMINATION CATEGORY E-D, SEALS, GASKE - i, AND MOISTURE BARRIERS Extent and Frequency of Examination Acceptance Inspection Standard Interval IWE-3513 . 100% of each item I Successive Inspection Intervals - 100% of each item 100% of each item Deferral of Inspection to End of Intervals Not perrnissible Not permissible NOTE: (1) Examination shall include seals and gaskets on airlocks, hatches, and other devices that are required to assure containment leak-tight Integrity.
(2) Examination shall include internal and external containment moisture barrier materials at concrete-to-metal interfaces intended to prevent intrusion of moisture against the pressure retaining metal containment shell or liner.
(3) Containment moisture barrier materials include caulking, flashing, and other sealants used for this application.
(4) Examination shall include all accessible surfaces of internal and external containment moisture barriers.
(51 Deferral of inspection is not permissible in the 4th and successive inspection intervals.
ARTICLE IWE-3000 ACCEPTANCE STANDARDS 1WE-3100 EVALUATION OF NONDESTRUCTIVE EXAMINATION RESULTS IWE-3110 PRESERVICE EXAMINATIONS IWE-3111 General The preservice examination required by IWE-2200 and performed in accordance with the procedures of IWA-2200 shall be evaluated by the acceptance stan-dards specified in Table IWE-3410-
- 1. Acceptance of components for service shall be in accordance with IWE-3 112, IWE-3114, and IWE-3115.
IWE-3112 Acceptance (a) Components whose examination either confirms the absence of or reveals flaws or areas of degradation that do not exceed the acceptance standards of Table IWE-3410-1 shall be acceptable for service, provided the flaws or areas of degradation are recorded in ac- cordance with the requirements of IWA-1400(h) and IWA-6220 in terms of location, size, shape, orienta- tion, and distribution within the component. (b) Components whose examination reveals flaws or areas of degradation that do not meet the acceptance standards of Table IWE-3410-1 shall be unacceptable for service unless such flaws or areas of degradation are removed or repaired, to the extent necessary to meet the acceptance standards, prior to placement of the component in service. IWE-3114 Repairs and Reexaminations Repairs and reexaminations shall comply with the requirements of IWA-4000. Reexamination shall be conducted in accordance with the requirements of IWA-2200; the recorded results shall demonstrate that the repair meets the acceptance standards specified in TabIe IWE-3410-1. IWE-3115 Review by Authorities (a) The repair program and the examination results shall be subject to review by the enforcement author- ities having jurisdiction at the plant site. (b) Evaluation of examination results may be subject to review by the regulatory authority having jurisdiction at the plant site. IWE-3120 INSERVICE NONDESTRUCTIVE EXAMINATIONS IWE-3121 General Inservice nondestructive examination results shall be compared with recorded results of the preservice ex- amination and prior inservice examinations.
Accep- tance of the components for continued service shall be in accordance with IWE-3122, IWE-3124, and IWE- 3125. IWE-3122 Acceptance IWE-3122.1 Acceptance by Examination.
Com- ponents whose examination results meet the acceptance standards listed in Table IWE-2500-1 shall be accept- able for continued service. Verified changes of flaws or areas of degradation from prior examinations shall be recorded in accordance with IWA-1400(h) and IWA-6220. Components that do not meet the accep- tance standards of IWE-3000 shall be corrected in ac- cordance with the provisions shown in IWE-3122.2, IWE-3122.3, or IWE-3 122.4.
IWE-3122.2 Acceptance by Repair. Components whose examination results reveal flaws or areas of deg- radation that do not meet the acceptance standards list- ed in Table IWE-2500-1 shall be unacceptable for con- tinued service until the additional examination requirements of IWE-2430 are satisfied, and the flaw or area of degradation is either removed by mechanical IWE-3122.2 REQUIREMENTS FOR CLASS MC COblPONkNTS IWE-3510.
l methods or the component repaired to the extent nec- lowing verification of the suspect areas by the supple- essary to meet the acceptance standards of IWE-3000.
mental examination as required by IWE-3200, the re- IWE-3122.3 Acceptance by Repla'cement. As an quirements of are satisfied. alternative to the repair requirement of IWE-3122.2.
the component or the portion of the component con- taining the flaw or area of degradation shall be replaced WE-3200 SUPPLEMENTAL in accordance with IWE-7000.
EXAMINATIONS IWE-3122.4 Acceptance by Evaluation (a) Components whose examination results reveal flaws or areas of degradation that do not meet the ac-ceptance standards listed in Table IWE-3410-1 shall be acceptable for service without the removal or repair of the flaw or area of degradation or replacement if an engineering evaluation indicates that the flaw or area of degradation is nonstructural in nature or has no ef- fect on the structural integrity of the containment.
When supplemental examinations of IWE-3200 are re- quired, if either the thickness of the base metal is re- duced by no more than 10% of the nominal plate thick-ness or the reduced thickness can be shown by analysis to satisfy the requirements of the Design Specifications, the component shall be acceptable by evaluation. (b) When flaws or areas of degradation are accepted by engineering evaluation, the area containing the flaw or degradalion shall be reexamined in accordance with IWE-2420(b) and (c). (c) When portions of later editions of the Construc-tion Code or Section I11 are used, all related portions shaIl be met. The engineering evaluation shall be sub- ject to review by the enforcement and regulatory au-thorities having jurisdiction at the plant site. Examinations that detect flaws or evidence of deg- radation that require evaluation in accordance with the requirements of IWE-3100 may be supple~nented by other examination methods and techniques (IWA-2240) to determine the character of the flaw (i.e., size, shape, and orientation) or degradation.
Visual examinations that detect surface flaws or areas that are suspect shall be supplemented by either surface or volumetric ex- amination. IWE-3400 STANDARDS IWE-3410 ACCEPTANCE STANDARDS The acceptance standards of Table IWE-3410-1 shall be applied to evaluate the acceptability of the com- ponent for service following the preservice examination and each inservice examination.
IWE-3430 ACCEPTABILITY Flaws or areas of degradation that do not exceed the allowable acceptance
'standards of IWE-3500 for the respective examination category shall be acceptable.
IWE-3124 Repairs and Reexaminations Repairs and reexaminations shall comply with the requirements of IWA-4000. Reexaminations shall be IWE-3500 ACCEPTANCE STANDARDS conducted in accordance with the requirements of IWE-3510 STANDARDS FOR EXAMINATION IWA-2200 and the recorded results shall demonstrate CATEGORY E-A, CONTAINMENT that the repair meets the acceptance standards of Table SURFACES IWE-3125 Review by Authorities The repair program and the reexamination results shxll be subject to review by the enforcement 'author-ities having jurisdiction at the plant site. IWE-3130 INSERVICE VISUAL EXAMINATIONS
' Components, whose visual examination as specified in Table IWE-2500-1 reveals areas that are suspect, shall be unacceptable for continued service unless, fol- IWE-3510.1 Visual Examinations - General (a) The General Visual Examination shall be per- formed by, or under the direction of, a Registered Professional Engineer or other individual, knowledge-able in the requirements for design, inservice inspec-tion, and testing of Class MC and metallic liners of Class CC components. The examination shall be per-formed either directly or remotely, by an examiner with visual acuity sufficient to detect evidence of degrada- tion that may affect either the containment structural integrity or leak tightness. (b) Prior to proceeding with a Type A test, condi- tions that nlay affect containment structural integrity or 1992 SECTION XI - DIVISION I TABLE 1WE-3410-1 ACCEPTANCE STANDARDS Examination Category Component and Part Examined Acceptance Standard E-A Containment surfaces IWE-3510 E- B Pressure retaining welds IW E-3511 E-C Containment surfaces requiring augmented IWE-3512 examination E- D Seals, gaskets, and moisture barriers IWE-3513 E- F Pressure retaining dissimilar metal welds IWE-3514 E-G Pressure retaining bolting IWE-3515 E- P All pressure retaining components 10 CFR 50, Appendix J leak tightness shall be accepted by engineering eval-in accordance with IWE-3200 shall be perfonned when uation or corrected by repair or replacement in accor- specified as a result of the engineering evaluation.
dance with IWE-3 122. IWE-3511.2 VT-I Visual Examinations on Non- IWE-3510.2 VT-3 Visual Examinations on Coated Areas. The inspected area, when painted or coated, shall be examined for evidence of flaking, blistering, peeling, discoloration, and other signs of distress. Areas that are suspect shall be accepted by engineering evaluation or corrected by repair or replacement in ac- cordance with IWE-3122. Supplemental examinations in accordance with IWE-3200 shall be performed when specified as a result of the engineering evaluation.
IWE-3510.3 VT-3 Visual Examinations on Non- coated Areas. The inspected area shall be examined for evidence of cracking, discoloration, wear, pitting. excessive corrosion, arc strikes, gouges, surface dis- continuities, dents, and other signs of surface irregu-larities.
Areas that are suspect shall be accepted by engineering evaluation or corrected by repair or re- placement in accordance with IWE-3122.
Supplemental examinations in accordance with IWE-3200 shall be performed
'when specified as a result of the engineering evaluation.
IWE-3511 Standards for Examination Category E-B, Pressure Retaining Welds IWE-3511.1 VT-I Visual Examinations on Coated Areas. The inspected area, when painted or coated, shall be examined for evidence of flaking, blistering, peeling, discoloration, and other signs of distress.
Areas that are suspect shall be accepted by engineering evaluation or corrected by repair or replacement in ac- cordance with IWE-3 122. Supplemental examinations coaled Areas. The inspected area shali be examined for evidence of cracking, discoloration, wear, pitting, excessive corrosion, arc strikes, gouges, surface dis- continuities, dents, and other signs of surface irregu- larities. Areas that are suspect shall be accepted by engineering evaluation or corrected by repair or re- placement in accordance with IWE-3 122. Supplemental examinations in accordance with IWE-3200 shall be performed when specified as a result of the engineering evaluation.
IWE-3512 Standards for Examination Category E-C, Containment Surfaces Requiring Augmented Examination IWE-3512.1 VT-I Visual Examinations on Coated Areas. The inspected area, when painted or coated, shall be examined for evidence of flaking, blistering, peeling, discoloration, and other signs of distress.
Areas that are suspect shall be accepted by engineering evaluation or corrected by repair or replacement in ac- cordance with IWE-3 122.
Supplemental examinations in accordance with IWE-3200 shall be performed when specified as a result of the engineering evaluation. IWE-3512.2 VT-1 Visual Examinations on Non- coated Areas. The inspected area shall be examined for evidence of cracking, discoloration, wear, pitting, excessive corrosion, arc strikes, gouges, surface dis- continuities, dents, and other signs of surface irregu-larities. Areas that are suspect shall be accepted by engineering evaluation or corrected by repair or re- placement in accordance with IWE-3 122. Supplemental IWE-3512.2 REQUlREMENTS FOR CLASS MC COMPONENTS IWE-3515.2 examinations in accordance with IWE-3200 shall be performed when specified as a result of the engineering evaluation.
IWE-3512.3 Ultrasonic Examination.
Containment vessel examinations that reveal material loss exceeding 10% of the nominal containment wall thickness, or ma- terial loss that is projected to exceed 10%
of the nom- inal containment wall thickness prior to the next ex- amination, shall be documented. Such areas shall be accepted by engineering evaluation or corrected by re- pair or replaceinenr in accordance with IWE-3 122. Supplemental examinations in accordance with IWE- 3200 shall be perfomled when specified as a result' of the engineering evaluation.
IWE-3513 Standards for Examination Category E-D, Seals, Gaskets, and Moisture Barriers IWE-3513.1 VT-3 Visual Examinations.
Seals, gaskets, and moisture barriers shall be examined for wear, damage, erosion, tear, surface cracks, or other defects that may violate the leak-tight integrity.
De- fective items shall be repaired or replaced.
IWE-3514 Standards for Examination Category E-F, Pressure Retaining Dissimilar Metal Welds IWE-3513.1 Surface Examinations.
The accep- tance standards of IWB-3514 shall apply within the ex- amination boundary of Fig. IWE-2500-1.
IWE-3515 Standards for Examination Category E-G, Pressure Retaining Bolting IWE-3515.1 Visual Examinations.
Bolting rnate- rials shall be examined in accordance with the material specification for defects which may cause the bolted connection to violate either the leak-tight or structural integrity. Defective items shall be replaced. IWE-3515.2 Bolt Torque or Bolt Tension. Either bolt torque or bolt tension shall be within the limits specified for the original design.
If no limits have been specified, acceptable bolt torque or bolt tension limits shall be determined and utilized.
UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD
In the Matter of )
)
AMERGEN ENERGY COMPANY, LLC ) Docket No. 50-219-LR ) (Oyster Creek Nuclear Generating Station) )
AFFIDAVIT OF HANSRAJ G. ASHAR I, Hansraj G. Ashar, do declare under penalty of perjury that my statements in the foregoing testimony and my attached statement of professional qualifications are true and correct to the best of my knowledge and belief.
/Original signed by/
____________________
Hansraj G. Ashar
Executed at Rockville, MD this 20th day of July, 2007 UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD
In the Matter of )
)
AMERGEN ENERGY COMPANY, LLC ) Docket No. 50-219-LR ) (Oyster Creek Nuclear Generating Station) )
AFFIDAVIT OF JAMES A. DAVIS, PH.D I, James A. Davis, do hereby declare under penalty of perjury that my statements in the foregoing testimony and my attached statement of professional qualifications are true and correct to the best of my knowledge and belief.
/Original signed by/
____________________
James A. Davis, Ph. D
Executed at Rockville, MD this 20th day of July, 2007
UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD
In the Matter of )
)
AMERGEN ENERGY COMPANY, LLC ) Docket No. 50-219-LR ) (Oyster Creek Nuclear Generating Station) )
AFFIDAVIT OF MARK HARTZMAN, PH. D I, Mark Hartzman, do hereby declare under penalty of perjury that my statements in the foregoing testimony and my statement of professional qualifications are true and correct to the best of my knowledge and belief.
/Original signed by/
____________________
Mark Hartzman, Ph. D
Executed at Rockville, MD this 20th day of July, 2007
UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD
In the Matter of )
)
AMERGEN ENERGY COMPANY, LLC ) Docket No. 50-219-LR ) (Oyster Creek Nuclear Generating Station) )
AFFIDAVIT OF TIMOTHY O'HARA I, Timothy O'Hara, do hereby declare under penalty of perjury that my statements in the foregoing testimony and my statement of professional qualifications are true and correct to the best of my knowledge and belief.
/Original signed by/
____________________
Timothy O'Hara
Executed at Medford, NJ this 20th day of July, 2007 UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION
BEFORE THE ATOMIC SAFETY AND LICENSING BOARD
In the Matter of )
) AMERGEN ENERGY COMPANY, LLC ) Docket No. 50-219-LR )
(Oyster Creek Nuclear Generating Station) )
CERTIFICATE OF SERVICE I hereby certify that copies of the ANRC STAFF INITIAL STATEMENT OF POSITION ON DRYWELL CONTENTION
@ , "NRC STAFF TESTIMONY OF HANSRAJ G. ASHAR, DR. JAMES A. DAVIS, DR. MARK HARTZMAN AND TIMOTHY O'HARA CONCERNING DRYWELL CONTENTION" , AFFIDAVITS of Hansraj G. Ashar, Mark Hartzman, James A. Davis and Timothy O'Hara in the above-captioned proceeding have been served on the following by electronic mail with copies by deposit in the NRC's internal mail system or as indicated by an asterisk, by electronic mail, with copies by U.S mail, first class, this 20th day of July, 2007.
E. Roy Hawkens, Chair
Administrative Judge Atomic Safety and Licensing Board Mail Stop: T-3F23 U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 ERH@nrc.gov Anthony J. Baratta
Administrative Judge Atomic Safety and Licensing Board
Mail Stop: T-3F23 U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 AJB5@nrc.gov
Paul B. Abramson
Administrative Judge Atomic Safety and Licensing Board Panel Mail Stop: T-3F23 U.S. Nuclear Regulatory Commission Washington, DC 20555-0001
PBA@nrc.gov Office of the Secretary*
ATTN: Docketing and Service Mail Stop: O-16C1 U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 HEARINGDOCKET@nrc.gov
Office of Commission Appellate Adjudication
Mail Stop O-16C1 U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 OCAAmail@nrc.gov Debra Wolf
Law Clerk Atomic Safety and Licensing Board Panel
Mail Stop: T-3F23 U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001
DAW1@nrc.gov
Suzanne Leta Liou NJ Public Interest Research Group 11 N. Willow St.
Trenton, NJ 08608 sliou@environmentnewjersey.org
Richard Webster, Esq.*
Rutgers Environmental Law Clinic 123 Washington Street Newark, NJ 07102-5695
rwebster@kinoy.rutgers.edu
Donald Silverman, Esq.* Alex S. Polonsky, Esq.* Kathryn M. Sutton, Esq.*
1111 Pennsylvania Ave., N.W.
Washington, DC 20004 dsilverman@morganlewis.com apolonsky@morganlewis.com
ksutton@morganlewis.com
J. Bradley Fewell, Esq.* Exelon Corporation 4300 Warrenville Road
Warrenville, IL 60555
bradley.fewell@exeloncorp.com
Paul Gunter, Director* Reactor Watchdog Project Nuclear Information
And Resource Service
6930 Carroll Avenue
Suite 340 Takoma ParK, MD 20912 E-mail: pgunter@nirs.org
/RA/ ____________________
Mitzi A. Young Counsel for the NRC Staff