ML091040727

Document No. 17693-R-001, Revision 0, NJDEP Oyster Creek Drywell Review

ML091040727
Person / Time
Site:	Oyster Creek
Issue date:	04/06/2009
From:	Hollinger G Becht Nuclear Services
To:	Office of Nuclear Reactor Regulation
References
17693-R-001, Rev 0
Download: ML091040727 (40)

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BEcHr NUCLEAR SERVICES Becht Nuclear Services

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NJDEP Oyster Creek Drywell Review Document No. 17693-R-001 Revision No. 0 (4/6/2009)

Prepared by:

G. L.Hollinger, P.E.

Reviewed by:

C.Becht IV,PhD., P.E.

Approved by:

G.A.Antaki, P.E.

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Oyster Creek Drywell Review Record of Revisions I Revision 0 4/6/2009: Initial Issue Description of Changes I1 j

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Oyster Creek Drywell Review Table of Contents Table of Contents ........................................................................................................................................ 3 Executive Sum mary ................................................................................................................................... 4

1. Intro d uctio n .......................................................................................................................................... 5

2. Sum mary of Results ........................................................................................................................... 7

3. Discussion and Conclusions ................................................................................................................ 17 3.1 Thinned Region Modeling Eccentricity Com ment .................................................................. . 17 3.2 Modified Capacity Reduction Factor Com ment .................................................................... . . 18 3.3 Review of SIA Reports [1] and [2] ........................................................................................ . . 20 3.4 Review of the Sandia Report ............................................................................................... . 20 3.5 Comparison of Results of the SIA Reports and the Sandia Report ........................................ 20 3.6 Review of Other References [4], [5], [6], [9], [9a] .................................................................. . 24 3.7 Conclusions and Recom mendations .................................................................................... . 25

4. References .......................................................................................................................................... 26 AppendixA Scope of Work .............................................................................................................. 28 Appendix B Review Observations with No Significance for Conservatism or Negative conservatism of the Analysis .................................................................................. . 29 Appendix C Editorial Com ments Associated with Technical Content ..................................................... . . 40 Becht Nuclear Services

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Ovster Creek Drvwell Review Executive Summary BNS conducted a review of the documents listed as References 1 through 9a herein. Adetailed review of the two Structural Integrity Associates Reports [1] and [2] was performed. A detailed review of the Sandia Report [3] was also performed. That review is a supplement to the overall evaluation and comparison with the SIA evaluations contained in their reports. The detailed review of the Sandia Report is not documented herein.

BNS believes that the SIA analysis reported in the 403 SIA Report [1] presents a modern, up-to-date deterministic evaluation of the Oyster Creek Drywell in accordance with ASME Section.Ill, Subsection NE [10]. The Code requirements are satisfied for the drywell in its current (2006-2008) state of degradation with assumed thin regions based on limited thickness measurements and as modeled based on those measurements. As with any such deterministic engineering evaluation, there are conditions and assumptions with both positive and negative effects on the accuracy and conservatism of the evaluations. These assumptions are typically acceptable, since the design margins included in the Code allowable stresses and other criteria are set to account for such typical unknown conditions.

The analysis of two sensitivity cases reported inthe 404 SIA Report [2] indicate that a modest reduction in thickness from the base case reported in the 403 Report [1] results in a slight increase in Code stress levels and a minimal effect on buckling safety factors, BNS believes that the two sensitivity cases presented in the SIA 404 Report do not represent an estimate of Code stresses and buckling factors at the end-of-extended-life, whereas the Sandia report does estimate an end-of-extended life condition. In both cases, however, Code limits are shown to be met. BNS concurs with those assessments based on the scope of review conducted and as reported herein.

BNS identified several items affecting the overall level of conservatism in SIA's evaluation of the drywell. The most significant is the possible level of negative conservatism associated with the hoop tension enhanced capacity reduction factors used for the refueling configuration evaluation. First, BNS shows that the required code buckling factor of safety (FS) is acceptable without use of Miller's modified capacity reduction factor. Inaddition, it is likely that with a less conservative treatment of the locally high theoretical buckling stress, paired with a more conservative treatment of the enhanced capacity reduction factors for each location of high compressive stress, the resulting buckling safety factors will continue to meet Code limits and will exhibit additional margin.

BNS believes that the uncertainty associated with the wall thinning measurements has been treated adequately for the measurements provided to-date, and as evaluated intwo sensitivity cases in SIA's 404 Report [2]. BNS believes that the SIA 404 report does not address end-of-extended life conditions, per se. However, rather than performing more analysis now, whether deterministically-, statistically- or probabilistically-based, BNS recommends that continued measurement of drywell thickness and evaluation be an ongoing process, and that the interval of inspections and measurements be done and evaluated as frequently as practicable in the early years of extended operation.

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Ovster Creek Drvwell Review 179--0 e.0(//09 NJE ytr Cre rwelRve

1. Introduction References in this report are denoted by [nn], where nn is a reference number listed in the References Section of this report. The agreed Upon Scope of Work for which this report is prepared is provided inAppendix A. The following items summarize the Scope of Work.

0 Perform a technical review of the three-dimensional structural analysis report of the Oyster Creek drywell.

The structural analysis is presented in two documents, which this review considers "the two principal documents":

o Structural Integrity Associates Report 0006004.403 RO, "Structural Evaluation of the Oyster Creek Drywell Summary Report" [1]. NOTE: This is termed the "403 Report" herein.

o Structural Integrity Associates Report 0006004.404 RO, "Oyster Creek Drywell Sandbed Region Wall Thinning Sensitivity Analyses Summary Report" [2]. NOTE: This is termed the "404 Report" herein.

• The review is to include an independent technical review covering these and other identified attributes:

• basis of acceptability of design inputs and assumptions

• methodology

• analytical modeling

• applied loadings

• sensitivity analysis

• other items as necessary

• specifically detail the validity of the capacity reduction factors used inthe analysis 0 The review is to be documented in a report to NJDEP-BNE including:

o Details and scope of the review performed o Executive Summary o Comprehensive discussion of findings of; N Evaluations E Opinions N Deficiencies 0 Safety Issues E Other Items The review considers the following documents as "supporting information" for the review.

• Sandia Report, SAND2007-0055, "Structural Integrity Analysis of the Degraded Drywell Containment at the Oyster Creek Nuclear Generating Station," NOTE: This is termed "The Sandia Report" herein.

• Sandia e-mail to NRC, February 9,2007 [4].

• NRC Memo to ACRS, March 8 [5].

• ASLB Memorandum, October 29, 2008:ASLB (Hawkens, Abramson and Baratta) [6].

• NJDEP-BNE Letter to NRC, September 16, 2008 [7].

• NJDEP-BNE Letter to NRC, January 30, 2009 [8].

• Results of Three-Dimensional Structural Analysis of the Oyster Creek Drywell Shell, Associated with AmerGen's License Renewal Application (TAC No. MC7624) [9].

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Oyster Creek Drywell Review The process used for the review is outlined as follows.

1. Review the provided documents [1] through [9] on a first-pass basis to gain an overall view of the material.

The issues identified inthat first-pass review include:

a. The capacity reduction factor tensile hoop stress for the refueling configuration evaluation.

b. Modeling of thin areas with the shell radius equal to the un-thinned shell radius.

c. The number of assumptions identified in lists and inthe text of the reports.

d. The relationship between the 1962 Section VIII requirements versusSection VIII Div. 2 and Section III, Subsection NE and use of a design-construction code (ASME Section III, Subsection NE) and minimum lower bound material properties for a fitness for service, life extension evaluation.

e. Ahorizontal earthquake load of 2,150 k and its relationship to the response spectrum loading.

f. Use of maximum attached piping support spans rather than spans as they exist in the plant.

g. Potential for material property degradation from aging or exposure to radiation.

h. Exemption from fatigue analysis with the irregularly shaped and potentially rough thin regions.

i. No projection of thinning to end-of-life.

j. Use of a solid model and linearization of stresses.

2. Perform a page-by-page review of both SIA reports 403 Report [1] and 404 Report [2], identifying questions and issues, recording them in a "notes table," recording the document (403 or 404 report), page number, location on the page, the topic of the issue, the reviewer comment, and an experience-based judgment of the level of conservatism, negative conservatism and any uncertainty associated with the comment. Each of the comments is associated with one or more of the attributes listed in the Scope of Work (listed above).

3. Conduct teleconferences with NJDEP, EXELON and SIA to resolve questions, and decide ifthe resolution closed the comment or continued to keep itas a comment.

4. Categorize and report the review comments as one of the following:

a. comments that illustrate positive (+)conservatism in the analysis.

b. comments that illustrate negative (-)conservatism in the analysis.

c. comments that illustrate neutral levels of conservatism inthe analysis.

d. comments that illustrate items of uncertainty.

d. technical-associated editorial comments (for information only).

5. Using the information in process step 4 above, determine an overall judgment of the level of conservatism that this analysis represents with respect to meeting the requirements of The American Society of Mechanical Engineers Boiler and Pressure Vessel Code,Section III, Subsection NE for Class MC Components [10]

supplemented by Nuclear Code Case N-284-1 [11] and two documents written by C. D. Miller, listed as references 23 and 26 of the 403 SIA Report [1]. WRC Bulletins 406 [12] and 462 [13] are used to supplement the review of the Miller references.

NOTE: The abbreviation "CRF" is used for "capacity reduction factor" throughout the report.

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Ovster Creek Drvwell Review

2. Summary of Results Table 2.1 provides an overview of the review results in the form of general comments for the documents provided to Becht Nuclear Services by NJDEP (references 1 through 9a).

Table 2hi x Overview of ReviewRResults'of Documents.Provided byNJDEP XJDEP,ýRetýNd- Content -statuis

[1] Structural Integrity Base Analysis Results, i.e., as-measured Page-by-page initial/dated Associates Report LTAs, but without sensitivity study. review complete. Issues 0006004.403 RO, marked on pages and "Structural Evaluation of recorded in a Table and the Oyster Creek Drywell categorized as an observation Summary Report" (ob, ob+ or ob-) indicating positive, negative or no impact on conservatism or with a level of uncertainty from -2 to 0.

[2] Structural Integrity Sensitivity Study of Wall Thinning inthe Page-by-page initial/dated Associates Report Sandbed region of the containment structure review complete. Issues 0006004.404 RO, "Oyster marked on pages and Creek Drywell Sandbed recorded in a Table and Region Wall Thinning categorized as an observation Sensitivity Analyses (ob, ob+ or ob-) indicating Summary Report." positive, negative or no impact on conservatism or with a level of uncertainty from -2 to 0.

[3] Sandia Report, Sandia's Independent Analysis of the Drywell Page-by-page initial/dated SAND2007-0055, review complete on marked "Structural Integrity pages. Used as source Analysis of the Degraded material and as a general Drywell Containment at comparison with SIA's the Oyster Creek Nuclear analysis.

Generating Station"

[4] Sandia e-mail to NRC, Comments about hoop tension based modified Information, with BNS February 9,2007 capacity reduction factors and Sandia's comments:

opinion that they should not be used for the refueling load combination because there is no internal pressure applied for that case.

[5] NRC Memo to ACRS, Explanation of misunderstanding created by a Information, with BNS March 8, 2007 presentation slide regarding the hoop stress comments.

tension issue, particularly as it relates to hoop tension being included inthe bifurcation analysis and then inthe capacity reduction factor.

[6] ASLB Memorandum, Discussions of issues regarding sensitivity Information, with BNS October 29, 2008 analyses, assignment of measured comments.

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Oyster Creek Drywell Review evaluate tme adequacy ot _XLLUN's analysis and its response to intervener's concerns expressed in meetings inthe Fall of 2008, and how the 3D analyses bound expectation of Jude Baratta's directive, and the issue associated with use of the modified capacity reduction factor for hoop stress tension.

[7] NJDEP-BNE Letter to expectations of AmerGen's 3D FEA evaluation Information NRC, September 16, of the drywell: based on measurements from 2008 Oct 2008 outage; determine ifall ASME Code allowables are met; submitted to NRC and NJDEP entirely; detailed version for independent review; NRC to review the.

documentation; NRC to discuss uncertainties; NRC to summarize its findings

[8] NJDEP-BNE Letter to Letter indicates the need for NRC and Sandia Information NRC, January 30, 2009 to review EXELON's analysis.

[9] Results of Three- Transmits The Structural Integrity Reports Information Dimensional Structural (403 and 404) as enclosures 1 and 2.

Analysis of the Oyster Creek Drywell Shell, Associated with AmerGen's License Renewal Application (TAC No. MC7624)

[9a] EELC Letter (Webster) to Request for Public Meeting and to Temporarily Additional document from Sammuel J. Collins Cease Power Production at Oyster Creek Scope of Work, for information March 24, 2009 Nuclear Generating Station on April 9, 2009. and BNS comments.

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Ovster Creek Drvwell Review Table 2.2 lists the positive conservatism items identified by BNS's review of the two SIA Reports [1] and [2].

NOTE: The term "ob+" signifies an observation exhibiting positive conservatism.

Table 2.2 Ta Observations That Illustrating Positive (+)Levels of Conservatism in the Analysis Source Report Item Description Comment Type of ReferenceComn 403, ASME Rules for Design and Use of a design code such asSection III, Subsection ob+

B&PV Code Construction NE to perform fitness for service evaluations is likely Section Il1, significantly conservative, including use of minimum Subsection NE, (design code based) properties rather than as-built 1998 properties.

403 pg 2-6; CBI Material Properties of The reviewer acknowledges that use of the ASME ob+

Drawings and as-built shell material.Section III Subsection NE code allowable stresses and Revisions physical properties is conservative for this evaluation.

Actual properties are likely higher, although they cannot be used to satisfy ASME Section III, Subsection NE requirements. This is considered a significant source of conservatism with respect to actual response of the drywell structure to loadings.

403 pg. 3-3 Using circular thinned Acceptable based on current industry practice, ob+

areas to encompass including ASME.

square measurement areas.

403 pg 4-3 item Gusset plates for guiding The reviewer agrees that the gusset plates for the ob+

2. pins not included in the guiding pins need not be included, and the model is model. likely slightly conservative.

403 pg 4-4, Modeling flange bolts as Reasonable modeling technique for local thin areas ob+

item 13. beam elements and and buckling evaluations. Exclusion of preload here is without preload. likely slightly conservative for evaluations of interest in this analysis.

403 pg 4-5, Concrete trenches in Stated to be conservative, and appropriately so, since ob+

item 21. Bays 5 and 17 extended exclusion of support tends to be conservative for this to sandbed region analysis.

bottom elevation 8 ft 11.25 in.

403 pg 5-15, 5- 2%damping OBE and Aconservative selection. ob+

18 4%for SSE 403 Page 6-2 Boundary Conditions. Conservative boundary conditions used, ignoring any ob+

support from the 3-inch air gap between the drywell and the concrete containment, which is filled with "compressible material". Use of only circumferential restraint from the male star-truss lugs is a conservative condition. Telecon 3126/09; SIA and EXELON explained that the only internal floor is at the bottom (10' 3"elevation). The reviewer agrees and the question on the comment is CLOSED.

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Oyster Creek Drywell Review eberaton Ti Positive ng I 403 pg 6-3, 3rd Structural boundary Reasonable modeling technique for this evaluation. ob+

para. conditions for portion of The use of only radial constraint in the bottom head is bottom head encased in likely insignificantly conservative, considering that the concrete and supported support skirt juncture with the drywell shell is restrained by embedded support horizontally and vertically.

skirt.

403 pg 6-4, 1st Drywell shell structural The "free" boundary conditions - allowing translation ob+

para. boundary conditions and rotation is all three directions - is potentially above embedded bottom conservative considering the restraint from the head. compressible material in the air space between the drywell shell and concrete building wall. Nonetheless, the reviewer agrees that the free boundary conditions are appropriate for this analysis. Telecon 3126109; SIA stated that the "no displacement" boundary condition means "free." The review agrees and the question on the comment is CLOSED.

403 pg 6-7 top Piping Spans for Actual data not used; lack of as-built information; a ob+

3 para. Connected Piping conservative uncertainty.

Deadweight 403; pg 6-7; The span of the Reasonable assumption, albeit an uncertainty, and ob+

item (b) unsupported piping likely conservative.

attached to penetrations to be "distance of maximum span from the penetration."

403; pg 6-7; The weight from half of Reasonable assumption, albeit an insignificant ob+

item (c) the maximum span of uncertainty, and likely conservative.

piping reacted at the penetration.

403; pg 6-7; Content of piping is Reasonable condition and conservative since not all ob+

item (d) water. piping will be full of water.

403; pg 6-8; 1st List of assumptions on Likely a reasonable conservative assumption. ob+

para, 1st line. page 6-7 are an upper bound of the gravity loads from attached piping system.

403; pg 6-8; Discussion about gravity Reasonable and likely conservative, ob+

entire page loads supporting list on after 1st line. pg 6-7 and list of items (a) through (d) 403, pg 6-13, OBE and SSE damping Appropriate. ob+

2nd para. at 2% and 4%

respectively per RG 1.61 and use of 2% for OBE, conservative.

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Oyster Creek Drywell Review 403, pg 7-2, Considering the post- An acknowledged conservative approach. ob+

section 7.3, 3rd accident case as a level para. C event.

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Oyster Creek Drywell Review Table 2.3 lists Observations illustrating (-)levels of conservatism in the analysis.

NOTE: The term "ob-" signifies an observation exhibiting negative conservatism.

Table 2:3 Observations Illustrating Negative (.)Levels of Conservatism in the Analysis Source Report Item Description' Comment Type of Page Comment Reference 403, 2006 and Thickness inspections of upper UT determination of existing thickness of drywell shell ob-2008 UT cylinder, sphere, sandbed region in local areas; presumes the thinnest area is found.

Inspections This is the information gained from the 2006 and 2008 outages which sets the "base" SIA evaluation. Itis likely that there may be other areas, and it is possible that there are thinner areas. However, what is used is a reasonable judgment of current degraded conditions without performing statistical analyses which would require definition of a probability of failure criteria. The item is therefore identified as a negative conservatism observation.

403 pg 3-3 Average of two adjacent bays Assigning wall-thinning to an area that may or may not ob-para. g assuming that there is a general exhibit it. The reviewer considers ita stated condition wall thickness gradient between with possible negative conservatism and uncertainty.

adjacent bays 403 pg 4-3 mid-thickness modeling, Modeling the mid-thickness of the un-thinned shell for ob-presumed to keep the unthinned regions whose outside is corroded, misses some shell centerline through all eccentricity and associated local moment when thinned areas. transitioning from thick shell to local thin area. See Fig. 3.1. Telecon 3126109; SIA explained that the use of the abrupt change in thickness generates fictitiously high stresses which are assumed to account for the missed eccentricity effect. Initially the reviewer agreed. Subsequent to the telecon, additional discussion within BNS has lead to a different opinion regarding the compensation of this missed effect by the step-change of thicknesses. BNS accepts that this could be a "second-order effect" and thereby identifies it as a potentially negative conservatism assumption.

NOTE: BNS is not in agreement that the thickness step change is a compensating effect for the missed eccentricity with the use of shell elements.

However, we do not believe that additional local bending stresses caused by this condition are a significant concern.

403 pg 4-4, Modeling of the sandbend Presumes, reasonably, that the insert plates are not ob-item 16. regions does not extend into the thinner than the local thin regions of the non-insert region where insert plates exist plate locations inthe sandbed region.

at the vent lines.

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Ovster Creek Drvwell Review NJE OytrCekDvelRve 1 ... 01Re

... .0 ...... O9 iLevels of Conservatismir Ieasonaole moaeiing tecnnique Tor iocai thin areas reinforcing plates and fillet welds and buckling evaluations, except the eccentric bending per Fig. 4-14. The plates are at these locations due to offset mid-planes of the shell presumed to be modeled by the is missed, causing negative conservatism.

total thickness (shell plus plate) and without mid-surface offset.

Mat rocking enveloped points out The statement implies an inaccuracy. Telecon 1S5 to the radius of the containment 3/26109; SIA will confirm adequacy of the rocking shell. information. 3/27/09 Written response: Q2: Report No. 0006004.403, Rev. 1 [1], Section 5.7.1.2, 1st paragraph states that "The difference is due to the change in the locations on the base mat (elevation 10'-3") where the spectra are computed. Both analyses include the effect of rocking of the mat.

The original analysis included the envelope of the spectra for locations on the mat that extended to the edge of the reactor building walls. The revised analysis included this same rocking effect but only enveloped the points out to the radius of the containment shell." Please elaborate on this statement. Response: The above statement is consistent with the description documented in the 4th paragraph of Section 4.2 in Reference 3. This methodology is adopted in the generation of the response spectra for the post-accident flooding condition. The approach taken by the revised analysis for spectra generation is acceptable.

403 pg 6-1 Circumferential gap assumed to The assumption is conservative for the local stresses ob-Section 6.2 (c). be closed, in the cylindrical shell as stated, but response to other parts of the drywell under various load combinations is not likely conservative, since stresses will be developed during closure of the gap. Telecon 3/26/09; SIA stated that the gap is 0.01 in. and that any stress caused by closure of the gap is negligible. The reviewer agrees, and the question on the comment is CLOSED. A slight level of negative conservatism is identified.

403; pg 6-7; The penetration is assumed as Reasonable assumption, albeit an insignificant ob-item (a) an anchor point or a support uncertainty and potentially an insignificant negative location. conservatism.

403, pg 6-15/6- Description and discussion of the The phrase "reasonable number" is taken as a ob-16, section modal frequency analysis. perceived Uncertainty.

6.5.8 403, pg 8-3, Capacity Reduction Factors and See Section 3.2 ob-section 8.3. Miller's Modified factor for tensile hoop stress [23].

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Oyster Creek Drvwell Review The combined effect of the identified conservatisms is judged to illustrate that the analysis is appropriately conservative. None of the observation-identified negative conservatisms are singly or in-combination significant enough to consider further action. They are judged to be the types of negative conservatisms that are covered by design margins included in ASME Codes and Standards.

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Ovster Creek Drvwell Review Table 2.4 lists the review items illustrating some level of uncertainty inthe analysis.

and 2008 UT of, I1upper 1 I"U bb11* III*JrtAIUlI I cylinder, Inspections sphere, sandbed reqion 403 pg 3-3 Average of two adjacent See Table 2.3 comment. -1 para. g bays assuming that there is a general wall thickness gradient between adjacent bays 403 pg 4-4, Modeling of the Presumes, reasonably, that the insert plates are not 0-item 16. sandbend regions does thinner than the local thin regions of the non-insert plate not extend into the locations inthe sandbed region. This is considered an region where insert insignificant uncertainty and likely not significant with plates exist at the vent respect to levels of conservatism.

lines.

403 pg 5-14, Small number of Use of the word "provided" implies that there might be 0-Section 5.5. penetrations provided more that were not provided.

with piping loads.

403 pg 5-15, Use of the response Stating that it is available, and is therefore the reason it 0-Section spectrum at 82 ft - 9 in. is used, implies uncertainty, and is likely not significant 5.7.1.1, 4th with respect to levels of conservatism.

line.

403 pg 6-7. Piping Spans for Actual data not used; lack of as-built information; an 0-Connected Piping insignificant, uncertainty and likely not significant with Deadweight respect to levels of conservatism.

403; pg 6-7; The penetration is Reasonable assumption, albeit an insignificant 0-item (a) assumed as an anchor uncertainty and likely not significant with respect to point or a support levels of conservatism.

location.

403; pg 6-7; The span of the Reasonable assumption, albeit an uncertainty, and likely 0-item (b) unsupported piping a positive conservatism.

attached to penetrations to be "distance of maximum span from the

____________ enetration."

403; pg 6-7; The weight from half of Reasonable assumption, and an insignificant 0-item (c) the maximum span of uncertainty, and likely insignificantly conservative.

piping reacted at the penetration.

403, pg 6- Description and The phrase "reasonable number" is a perceived 0-15/6-16, discussion of the modal uncertainty, but likely not significant with respect to (perceived)

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17693-R-001 Rev. 0(4/6/2009) NJDEP Ovster Creek Drvwell Review Review Items Illustrating So,ýme Laevel~o~ncertinfjy section 6.5.8 frequency analysis. levels of conservatism.

403, pg 6-16, Identification of the first The reasons for stating that the first significant mode is 0-2nd para. significant mode for the the 5th mode are missing. This is a perceived (perceived) refueling configuration uncertainty, but likely not significant with respect to case. levels of conservatism.

404, pg viii, The purpose of the 404 The purpose of the 404 report is to address "potential -1 pg. 1-1, 1-2, report. questions regarding uncertainties." The purpose, 1-3. therefore is not to provide a definitive estimate of any extended end-of-life condition for thinning, such as an extrapolation of continued degradation as is done in the Sandia Report [3]. The "postulated additional thinning" in the 404 report is limited to 1) additional local thinning in Bay 1 from 696 mils to 596 mils, a 14% decrease in thickness; 2) general thinning of Bay 19 from 826 mils to 776 mils, a 6% decrease in thickness.

Table 2.5, which is placed in Appendix B, lists "technically-associated" editorial comments. These comments are associated with a technical aspect of the report, such as a reference number or equation, These are provided for information only, and they have no bearing on the technical evaluation. The reviewer states that these editorial comments are typical and should not be considered as an adverse reflection on the technical quality of the Reports

[1] and [2].

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Ovster Creek Drvwell Review 3.0 Discussion and Conclusions 3.1 The Thinned Region Modeling Eccentricity Comment. Regarding the comment in Table 2.3, for the 403 Report, pg 4-3, Figure 3.1 is provided as a supplemental description.

Figure 3.1 Thinned Region Eccentric Modeling Comment CL Drywell Shell nodes I

Mid-thickness radius from drywell centerline Un-thinned Area I ruflfi <<< This Versus This >>>

(presumed)

I i Transition Area Un-thinned Area I n Measured thickness (Loss on the OD)

Thinned Area rthin I

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Ovster Creek Drvwell Review 3.2 Modified Capacity Reduction Factor Comment. Figures 3.2 and 3.3 are provided as a supplement to the comment on Section 8.3 of the 403 Report [1] from Table 2.3.

Figure 3.2 shows a case where the maximum compressive and maximum tensile stresses are approximately at the same location. Both the compressive stress and hoop tensile stresses are high (absolute values) in a local region - the blue circular region and the red circular region in Fig. 3.2. BNS believes that such a condition is not one that clearly justifies the use of the hoop tensile stress modified CRF, as SIA has done.

Nonetheless, it may be possible to define an appropriate local characteristic length to mitigate the effects of taking the locally highest value of compressive stress. A portion of that line may be used over which to average compressive buckling stress. Similarly, it may be possible to define an appropriate hoop-direction local characteristic length to assure that an adequate region of hoop tension exists to provide the purported benefits of hoop tension on the CFR.

Figure 3.3 shows a case where the maximum compressive and maximum tensile stresses are not at the same location, which BNS believes would not qualify for using the modified Miller equation [23].

Figure 3.2 Modified Capacity Reduction Factor for Tensile Hoop Stress (Fig. 8-7a of SIA's 403 Report [1])

jut (a) Mcridional Maximum hoop tensile stress 4,595 psi 4.60 ksi used for Bay 17 in Table 8-7, presumed to correspond to the 4,595 psi maximum tensile hoop stress Hoop Stress.

Figum 8-7; Refueling Buckling Stress. Sandbed Region Dt; Ith u*tUUdiOVI VIL*b ' UI, 4 VVUUUlUC rAMULIVU Aiken, SC 29803 Tel. 803-648-7461 www.bechtns.com

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Oyster Creek Drvwell Review Figure 3.3 Modified Capacity Reduction Factor for Tensile Hoop Stress (Fig. 8-9a of SIA's 403 Report [1])

.... .. . ,,* ,,,,,*Locally high com pressive stri

-4??

II ]?II

-3)

~ C?)) -IS

. C~

-I)

IZ i

(a) Mcridioinal Stress Maximum hoop tensile stress 3,327 psi "MUMiC 3.33 ksi used for Bay 3 in Table 8-7, presumed to correspond to the 3,327 psi maximum tensile hoop stress, where are the hoop stress at the same location for maximum compressive stress is actually compressive (dark blue contour, -1742 psi)

--- 7 -5.1 ------CA-----

(b) Hoop Shrm, Figure 8-9: Refuei~ng Buckling Stm,csBay 3 SandbedRegion Becht Nuclear Services

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Oyster Creek Drywell Review 3.3 Review of the SIA Reports [1] and [2]. These reports represent a modern analysis of the Oyster Creek Drywell. The reports show that the drywell currently meets, and will likely continue to meet, the requirements of the ASME Boiler and Pressure Vessel Code,Section III, Subsection NE. These reports provide a conservative means of justifying continued operation in that the ASME Code being used is one written for Design and Construction of Equipment that has not yet been built or operated. The reviewer acknowledges that such is the regulatory requirement. Nonetheless, the reviewer considers this approach to be more conservative than using modern fitness for service evaluation techniques, which ifused on the drywell, would likely show more margin than the current analyses reported in the two SIA Reports [1] and [2].

The use of Miller's modified capacity reduction factor [23] for the refueling case is not appropriate for all locations as explained in Section 3.2. However, when the modified factors are not used (more conservative), the resulting buckling safety factors meet N-284-1 [24].

3.4 Review of the Sandia Report [3]. The Sandia Report also represents a modern analysis of the Oyster Creek Drywell using an industry-typical 3D finite element analysis.

The results differ somewhat from the SIA analysis, and those differences, on a bottom-line basis are discussed in a following section. The principal -- and most significant -

difference is Sandia's treatment of the tensile hoop-stress based capacity reduction factor for the refueling configuration evaluation. Sandia's treatment is acknowledged to be more conservative than SIA's treatment. The reviewer's opinion is that a more accurate representation of the tensile hoop stress capacity reduction factors lies somewhere between Sandia's approach and SIA's approach, as noted in Section 3.2.

The reviewer believes that there are conservatisms in both Sandia's approach, and in SIA's approach regarding use of the highest axial compressive stress, "at a point" when it is more likely that buckling response is more of a global phenomenon, and that use of an averaging scheme as a function of the buckling mode would be more representative of buckling behavior - also as noted'in Section 3.2.

3.5 Comparison of Results of the SIA Reports and the Sandia Report. Tables 3.1a and 3.1b show the controlling case differences in the base versus degraded stress evaluations for SIA and Sandia, respectively. The reviewer's interest in this comparison is that the SIA 404 report states (Section 6) that there is insignificant increase of stress from the base case to the two degraded (sensitivity) cases. By contrast, The Sandia Report (Section 4.3) states that there is a significant increase in stress from their base case to their degraded case.

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17693-R-001 Rev. 0 (4/6/20091 NJDEP Ovster Creek Drvwell Review NJE OytrCekDvelRve 179--01Rv (46209 Table 3.1a Comparison of Controlling Results from SIA; [(arsenswavt - O'base)Obase]%

1 Sensitivity Case 1; 2= Sensitivity Case 2 1 2 1 2 1 2 2 Case PL PL PL+Pb PL+Pb PL+Pb lPL+Pb lp+Q 1p+Q P+Q P+Q Top Bot Top Bot Top Bot Top Bot Bay 1, LC5 (Refueling) 3.7% 0.0% 0.5% 0.1% 0.2% 0.1% 0.2% -1.8% 0.1% 0.2%

Bay 1, LC6 (Refueling) 5.6% 2.1% 2.1% 0.8% 2.9% 2.4% 0.7% -2.5% 2.3% 0.2%

Bay 1, LC9 (Post-Accident) -2.1% 0.2% -0.3% 5.0% 0.1% 0.4%

Bay 1, LC10 (Post-Accident) -0.3% 0.0% 4.6% 6.7% 1.4% 0.8%

Bay 19, LC5 (Refueling) 0.1% 3.7% 1.8% 0.9% 0.7% 2.2% 0.8% 0.2% -0.3% -0.7%

Bay 19, LC6 (Refueling) 0.0% 2.8% 0.2% 0.1% 1.5% 3.5% 0.1% 0.1% 0.3% -1.3%

Bay 19, LC9 (Post-Accident) 0.1% 3.4% 0.1% 0.1% 3.3% 3.5%

Bay 1, LC10 (Post-Accident) 0.2% 3.0% 0.2% 0.1% 1.1% 3.6%

Max 5.6% 3.7% 4.6% ,6.7% 3.3% 3.6% 10.8% 0.2% 2.3% 0.2%

Max(Max) 15.6% 1 1 6.7% [ 3.6% 1 0.8% 1 2.3%

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Oyster Creek Drywell Review Table 3.1b Comparison of Controlling Code Stress Results from Sandia; [(degraded - base)/ base]*

Sandia Tables 3-1 and 3-2 Maxial Mhoop M+B Ax M+B Hoop Cylinder Refueling 9.2% 8.3% 8.2% 7.2%

Knuckle Refueling 1.7% 1.0% 2.1% 1.2%

Upper Sphere Refueling 8.8% 14.8% 10.7% 12.1%

Middle Sphere Refueling 23.8% 24.0% 22.4% 23.1%

Thickened Middle Sphere Refueling 26.9% 32.2% 21.1% 48.5%

Lower Sphere Refueling 16.2% 28.3% 14.5% 24.7%

Local Region 1 Refueling NA NA NA NA Local Region 13 Refueling NA NA NA NA MIN/MAX MAX 26.9% 32.2% 22.4% 48.5%

MIN 1.7% 1.0% 2.1% 1.2%

Sandia Tables 3-1 and 3-2 Maxial Mhoop M+B Ax M+B Hoop Cylinder Post-Accident 7.1% 2.3% 5.6% -0.3%

Knuckle Post-Accident -7.0% -7.8% -4.0% -200.0%

Upper Sphere Post-Accident 2.1% 10.2% 10.1% 8.5%

Middle Sphere Post-Accident 16.0% 15.2% 19.3% 14.8%

Thickened Middle Sphere Post-Accident 10.9% 28.4% 27.7% 21.7%

Lower Sphere Post-Accident 30.8% 31.1% 14.4% 38.2%

Local Region 1 Post-Accident NA NA NA NA Local Region 13 Post-Accident NA NA NA NA MIN/MAX MAX 30.8% 31.1% 27.7% 38.2%

MIN -7.0% -7.8% -4.0% -200.0%

Sandia Tables 3-3 and 3-5 Maxial Mhoop M+B Ax M+B Hoop Cylinder Accident 9.7% 9.6% 11.9% 9.3%

Knuckle Accident 1.1% 1.2% 1.4% 1.2%

Upper Sphere Accident 6.9% 7.5% 6.6% 7.2%

Middle Sphere Accident 15.0% 18.7% 23.1% 14.2%

Thickened Middle Sphere Accident 11.5% 10.6% 17.5% 11.1%

Lower Sphere Accident 40.3% 34.5% 88.0% 41.6%

Local Region 1 Accident NA NA NA NA Local Region 13 Accident NA NA NA NA MIN/MAX MAX 40.3% 34.5% 88.0% 41.6%

MIN 1.1% 1.2% 1.4% 1.2%

Table 3.1a shows a maximum increase from base-to-degraded cases for SIA's evaluation as 6.7%.

Table 3.1s shows a maximum increase from base-to-degraded cases for Sandia's evaluation as 88.0%.

The reviewer concludes that this difference is explained by the significantly different thicknesses used in the base and degraded cases by SIA and Sandia. Table 3.2 provides a base and degraded modeled thickness comparison.

Sandia' base case is for the as-built, un-degraded condition, i.e., the condition at beginning of life. This appears to be the principal difference that leads to the two apparently different conclusions about the amount of increase in stress from base-to-degraded conditions.

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Oyster Creek Drywell Review NOTE: In this comparison, the reviewer notices differences in material properties and allowable stresses.

However, none of the differences are significant to the review reported herein.

Table 3.2 provides a comparison of the Base and Degraded thicknesses used by SIA and Sandia.

1. Main cylinder: no additional degraded thickness for SIA, and a 55 mil degraded thickness for Sandia.

2. Upper Sphere: no additional degradedthickness for SIA, and a 46 mil degraded thickness for Sandia.

3. Middle Sphere: no additional degraded thickness for SIA, and a 100 mil degraded thickness for Sandia.

4. Bottom Sphere: no additional degraded thickness for SIA, and no degraded thickness for Sandia.

5. Local Region 1: 230 mils degraded thickness for SIA thin region; 449 mils for Sandia general.

6. Local Region 13/19: 50 mil general and 106 mils local for SIA; 546 mils for Sandia genera!.

SIA's "base" is already degraded to account for the 2006 inspection measurements. Sandia's "base" is per original construction drawings. Hence, the larger difference in the base-degraded conditions for Sandia than for SIA.

Table 3.2 Comparison of SIA and Sandia Base and Degraded Thicknesses Degraded SIA SIA Base. SIA-1 SIA-1 SIA-2 SIA-2 Sandia Sandia Thicknesses Base Thin General Thin General, Thin Base Degraded (mils) Regions Regions Regions Cylinder (Main) 604 604 604 604 604 604 640 585 Upper Sphere 676 676 676 676 676 676 722 676 Middle Sphere 678 678 678 678 678 678 770 670 Bottom Sphere 636 636 636 636 636 636 676 676 Local Region 1 826 696 826 596 826 596 1,154 705 or Bay 1 _ 1 Local Region 13 826 720 826 720 776 720 1,154 618 or Bay 19 Becht Nuclear Services. 5224 Woodside Executive Court, Aiken, SC 29803 - Tel. 803-648-7461

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Ovster Creek Drvwell Review 3.6 Review of Other References [4], [5], [6], [9a] Regarding Key Issues Identified Therein.

3.6.1 Reference [4] is an email communication from Sandia on the modified capacity reduction factor.

This two-page email summarizes Sandia's concerns related to the use of the modified reduction factor on the drywell refueling configuration evaluation. One concern is the "double-counting" effect of including hoop tension in the finite element model and then using the hoop tension capacity reduction factor modification. BNS believes that there is no double-counting as Sandia describes. However, BNS believes that application of the modified capacity reduction factor for locations that exhibit high localized compressive stresses in the presence of tensile stress somewhere else, or even at the same location is not justifiable. Another item of concern is the use of the modified CRF for shells that have undergone years of operation with environmentally induced degradation. BNS acknowledges that this is an arguable point, as Sandia states. However, ifthat position were adopted, then it would be inappropriate to use even for the flooded condition when there is internal pressure.

3.6.2 Reference [5] is a Memorandum to ACRS from NRC regarding explanation of Sandia's presentation on February 1,2007. The main issue is the apparent misunderstanding of what did and did not constitute taking account of hoop tension.

3.6.3 Reference [6] is a Hearing Summary of October 29, 2008 describing the status of the process of review of SIA's analysis. The summary includes discussion of thin area measurements, inspections and suggested evaluation sensitivity studies, including use of 75 mils of thinning instead of 50 mils for Bay 19.

A Monte Carlo uncertainty analysis was suggested by the "Citizens." BNS notes that if such a probabilistic-based approach were to be taken, the entire analysis would then need to be done using agreed-upon probabilistic methods, with probabilities of failure and consequences of failure identified to be meaningful.

3.6.4 Reference [9a] is a letter from EELC March 24, 2009 to NRC requesting that Oyster Creek cease power production on April 9, 2009 because of several issues, including that the SIA analysis does not fulfill commitments, that the SIA analysis does not use the 75 mil thinning for two adjacent bays, and that ifthe modified capacity reduction factor had not been used, the margin for the refueling case could be significantly reduced (60%).

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17693-R-001 Rev. 0 (4/6/2009) NJIDEP Ovster Creek Drvwell Review 3.7 Conclusions and Recommendations.

BNS believes that the SIA analysis reported in the 403 SIA Report [1] presents a modem, up-to-date deterministic evaluation of the Oyster Creek Drywell in accordance with ASME Section III, Subsection NE [10]. The Code requirements are satisfied for the drywell in its current (2006-2008) state of degradation with assumed thin regions based on limited thickness measurements and as modeled based on those measurements. As with any such deterministic engineering evaluation, there are conditions and assumptions with both positive and negative effects on the accuracy and conservatism of the evaluations. These assumptions are typically acceptable, since the design margins included in the Code allowable stresses and other criteria are set to account for such typical unknown conditions.

The analysis of two sensitivity cases reported inthe 404 SIA Report [2] indicate that a modest reduction in thickness from the base case reported in the 403 Report [1] results in a slight increase in Code stress levels and a minimal effect on buckling safety factors. BNS believes that the two sensitivity cases presented in the SIA 404 Report do not represent an estimate of Code stresses and buckling factors at the end-of-extended-life, whereas the Sandia report does estimate an end-of-extended life condition. In both cases, however, Code limits are shown to be met. BNS concurs with those assessments based on the scope of review conducted and as reported herein.

BNS identified several items affecting the overall level of conservatism in SIA's evaluation of the drywell. The most significant is the possible level of negative conservatism associated with the hoop tension enhanced capacity reduction factors used for the refueling configuration evaluation. First, BNS shows that the required code buckling factor of safety (FS) is acceptable without use of Miller's modified capacity reduction factor. Inaddition, it is likely that with a less conservative treatment of the locally high theoretical buckling stress, paired with a more conservative treatment of the enhanced capacity reduction factors for each location of high compressive stress, the resulting buckling safety factors will continue to meet Code limits and will exhibit additional margin.

BNS believes that the uncertainty associated with the wall thinning measurements has been treated adequately for the measurements provided to-date, and as evaluated in two sensitivity cases in SIA's 404 Report [2]. BNS believes that the SIA 404 report does not address end-of-extended life conditions, per se. However, rather than performing more analysis now, whether deterministically-, statistically- or probabilistically-based, BNS recommends that continued measurement of drywell thickness and evaluation be an ongoing process, and that the interval of inspections and measurements be done and evaluated as frequently as practicable in the early years of extended operation.

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17693-R-001 Rev. 0 (4/6/2009) NJIDEP Ovster Creek Drvwell Review 4.0 References The principal references - those subject to review or provided to BNS by NJDEP are listed inTable 4.1, termed "Principal References." References identified by BNS's review are included in Table 4.2 as "Additional References."

Table 4.1 Principal References NJDEP Ref No. Author Date - Pages Filename

[1] Structural Integrity Associates Report Kok, Soo Bee 1/9/2009 270 OC Drywell 3-D 0006004.403 RO, "Structural Evaluation of (SIA) pp Analysis 1 of the Oyster Creek Drywell Summary Report" 2.pdf

[2] Structural Integrity Associates Report Kok, Soo Bee 1/9/2009 129 OC Drywell 3-D 0006004.404 RO, "Oyster Creek Drywell (SIA) pp Analysis 2 of Sandbed Region Wall Thinning Sensitivity, 2.pdf Analyses Summary Report."

[3] Sandia Report, SAND2007-0055, "Structural Petti, Jason P. January 102 Ref 3 Sandia Integrity Analysis of the Degraded Drywell (Sandia) 2007 pp Report.pdf Containment at the Oyster Creek Nuclear Generating Station"

[4]1 Sandia e-mail to NRC, February 9,2007 Hessheimer, 2/9/2007 5 pp Ref 4 Sandia e-Michael (Sandia) mail to NRC.pdf

[5] NRC Memo to ACRS, March 8, 2007 Kuo, P. T (NRC) 3/8/2007 7 pp Ref 5 NRC Position to Sandia e-mail.pdf

[6] ASLB Memorandum, October 29, 2008 ASLB (Hawkens, 10/29/2008 26 pp Ref 6 ASLB Abramson and October 29 Baratta) 2008.pdf

[7] NJDEP-BNE Letter to NRC, September 16, Lipoti, Jil 9/16/2008 2 pp Ref 7 BNE 9 2008 08 Ltr 3D Analysis.pdf

[8] NJDEP-BNE Letter to NRC, January 30, Lipoti, Jil 1/30/2009 2 pp Ref 8 BNE 1 2009 09 Ltr 3D Analysis.pdf

[9] Results of Three-Dimensional Structural Gallagher, 1/22/2009 3 pp Transmittal for Analysis of the Oyster Creek Drywell Shell, Michael P. Ref. 1 and 2.

Associated with AmerGen's License Renewal Application (TAC No. MC7624)

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Oyster Creek Drywell Review Table 4.2 Additional References

[10] The American Society of Mechanical Engineers, Boiler and Pressure Vessel Code, Section II1, Subsection NE for Class MC Components, 1989 Edition with Winter 1991 Addenda.

[11] The American Society of Mechanical Engineers, Boiler and Pressure Vessel Code , Nuclear Code Case N-284-1, 1995.

[12] WRC Bulletin 462, "Commentary on the Alternative Rules for Determining Allowable Compressive Stresses for Cylinders, Codes, Spheres and Formed Heads for Section VIII, Divisions 1 and 2," The Welding Research Council, Inc., New York, NY, 2001.

[13] WRC Bulletin 406, "Proposed Rules for Determining Allowable Compressive Stresses for Cylinders, Cones, Spheres and Formed Heads," The Welding Research Council, Inc., New York, NY, 1995.

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Oyster Creek Drywell Review 1 63R01Rv.0(//09 NJEPyte Cre Revie Appendix A Scope of Work SCOPE OF WORK Item (1) - Technical Review of Report Provide a fixed price to perform a technical review of the three-dimensional structural analysis report of the Oyster Creek drywell submitted to the NRC by Exelon Nuclear on January 22, 2009. The review need not be a number-by number verification of the calculation but rather an independent technical review which shall cover, but not be limited to, the basis and acceptability of design inputs and assumptions, methodology, analytical modeling, applied loadings, sensitivity analysis and ASME Code compliance.

The review shall specifically address in detail the validity of the capacity reduction factors used in the analysis.

Should the technical review of the analysis require information not included in the submitted report and not otherwise publicly available, such information would be made available by Exelon Nuclear at the Oyster Creek Generating Station, in Lacey Township, NJ, or at Exelon Nuclear offices, in Kennett Square, PA, or via conference calls (any and all meetings or calls to be arranged by NJDEP-BNE), under provisions of a proprietary agreement restricting the dissemination of such information.

Results of the technical review shall be documented in a report to NJDEP-BNE and shall include, but not be limited to, details and scope of the review performed, comprehensive discussion of any findings, evaluations, opinions, deficiencies and/or safety issues. An Executive Summary shall be part of this report. This report shall be completed and provided to NJDEP-BNE on or before April 6, 2009 unless otherwise agreed to by NJDEP-BNE.

Consultation with NJDEP-BNE relating to this technical review (including briefings, findings and comment resolution related to the final report) should be included as part of this line item.

This technical review shall be performed by an expert (PhD) in the field.

In addition, please advise us of any possible conflicts of interest with Exelon Nuclear (owner/operator Oyster Creek Nuclear Generating Station) or their predecessor AmerGen, LLC, and/or Structural Integrity Associates, Inc., San Jose, CA (consultant to Exelon who prepared report that is to be reviewed).

Note: NJDEP-BNE has been working closely with the NRC on this issue.

Therefore, any work you may have done with the NRC would not be considered a conflict of interest.

Item (2) - Possible Follow-ur Consultation Consultation and/or other supporting services provided to NJDEP-BNE subsequent to acceptance of the final report shall be billed on an hourly-rate (provide hourly-rate).

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Ovster Creek Drvwell Review Appendix B Review Observations with No Significance for Levels of Conservatism or Uncertainty 4UJ, ubi ana utL Acceptable, and other than modeling the Drawings measurement-based local thin regions, the modeling does not include "imperfections" that are covered by the capacity reduction factors in the buckling evaluation.

403, CBI and GE Loads and Load Combinations Acceptable, based on consideration of original Reports analyses.

403 Report Evaluation of ASME Section III Appropriate, using the bifurcation methods and Code Subsection NE Buckling Case N-284-1 (or -2).

Requirements 403 Page 4-1 Shell Element Finite Element Model Industry practice; very extensive model with significant with 208 penetrations geometric detail beyond needs of the analysis.

403 pg 4-3 item Transition thicknesses. Reasonable modeling technique for local thin areas

3. and buckling evaluations using shell elements.

403 pg 4-3, item Penetrations with reinforcing plates; Reasonable modeling technique.

4. welds same materials as pipe; shell thickness of weld is equal to throat thickness of weld; radius to mid-thickness of reinforcing plate.

403 pg 4-3, item Penetrations with insert plates; Reasonable modeling technique.

5. transition zones are assigned the same materials as the insert plates.

403 pg 4-3, item Vertical location of the lower flange Reasonable modeling technique using shell elements.

6. bolting ring and outer water seal at mid-point thicknesses.

403 pg 4-3, item Star truss assembly modeled with Reasonable modeling technique for this evaluation.

7. male lug and base plate and the ihside truss assembly.

403 pg 4-4, item Lifting lugs not modeled. Reasonable modeling technique for this evaluation.

9.

403 pg 4-4, item Fillet radii and corner radii of insert Reasonable modeling technique for this evaluation

10. plates not included since cyclic loading is not of interest, and is exempt in accordance with Section III, Subsection NE fatigue analysis exemption rules.

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17693-R-001 Rev. 0 (4/6/2009) NJIDEP Ovster Creek Drvwell Review 403 pg 4-4, item Knuckle region weld plates using fillet Reasonable modeling technique using shell elements.

11. weld dimension for mid-surface node location.

403 pg 4-4, item Modeling the head/shell flange as a Reasonable modeling technique for this evaluation.

12. rigid joint. NOTE: The reason given (use of shell elements) is not really a reason. The reviewer believes that the reason is that the evaluation of the drywell shell for local thin areas and buckling does not require detailed modeling of the joint. It is likely that any local sliding effects that are not captured with the modeling used do not interact significantly with the areas of concern inthis analysis.

403 pg 4-4, item Penetrations smaller than 3 inches Reasonable modeling technique for this evaluation.

14. are not modeled.

403 pg 4-4, item Penetration pipe truncated 3 inches Reasonable modeling technique for this evaluation.

15. from the drywell shell. Interaction effects of longer truncation lengths are likely insignificant.

403 pg 4-4, item Two general thicknesses inthe Appears just to be a statement describing Fig. 4-13,

17. sandbed region at 11 ft and one which lacks informative labels.

below that.

403 pg 4-4, item Manhole details, insert plates in top Reasonable modeling technique for this evaluation

8. head and access openings in star truss insert plates not included.

403 pg 4-5, item Modeling of penetrations with insert Appropriate. Fig. 4-15 needs some informative labels 19 and page 4-2, plates; model insert plate transition consistent with the description.

next-to-last as average of insert plate and shell para.. plate thicknesses per Fig. 4-15.

403 pg 4-5, item Modeling of equipment/personnel Reasonable modeling technique for this evaluation

20. hatch simplified.

403 pg 4-5, item Bay 5 trench portion modeled with Not clear to the reviewer, but appears to be an

22. 10.5 inch constant width. acceptable modeling feature. Telecon 3126/09; SIA explained that this is the sand bed area access trench. The reviewer understands, and the question on the comment is CLOSED.

403 pg 4-6, 2nd Modeling the vent Reasonable modeling technique for this evaluation para. header/downcomer with just support stiffness.

403 pg 4-6, 3rd ANSYS Modeling versus analysis Use of an earlier ANSYS version to generate the model para. revision, and then use of a later version to perform the analysis is presumed to be covered under the scope of SIA's Software V&V process. Complete V&V for version 8, Oyster Creek version. Telecon 3/26109; SIA explained that their V&V has addressed this. The comment is CLOSED.

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NJDEP Ovster Creek Drvwell Review 17693-R-001 Rev. 0 (4/6/2009) N

,lvewewObserations withKNpoSignifi cance for Levels of :Conse4ratism orUncertainty 403 pg 4-6, item Modeling the perforated deflector Reasonable modeling technique for this evaluation

23. plates as equivalent property-based solid plates per Fig. 4-17.

403 pg 4-9, Mesh sizes. Reasonable modeling technique for local thin areas Table 4-2. and buckling evaluations. Reference to any mesh sensitivity study would be useful regarding the ability to capture required local buckling modes. Telecon 3/26/09. SIA stated that the mesh study is now documented. The question on the comment is CLOSED.

403 pg 5-9 FSAR modified load conditions and Reduced internal pressure from 62 psi to 44 psi. Any combinations ASME code stamp design pressure marking issues are presumed to have been addressed in FSAR.

403 pg 5-10, 2nd Normal operating internal pressure Stated condition from reference document.

para. atmospheric at 15eF and external 2 psig at 205F.

403 pg 5-10, last Gravity loads and live loads are The reviewer presumes this means that added weight line. treated as quasi-static load in the or mass has been added to the mass density of the analysis. shell elements. Telecon 3/26/09; SIA confirmed that and the question on the comment is CLOSED.

403 pg 5-11, 1st Temporary load from fluid concrete A construction load, no longer of concern.

para. not evaluated.

403 pg 5-11, 3rd P6sload is not included. Load transmitted from the reactor to the concrete para. containment building without bearing on the drywell shell.

403 pg 5-11, 4th Loads not distinguished as SSE or The purpose of the statement is not clear, and could para. OBE. imply inaccuracy or conservatism issues. Telecon 3/26109; Although not explicitly covered in the telecon, other discussions provided explanation sufficient enough to consider the question on the comment to be CLOSED.

403 pg 5-11, last Ps and P2 loads referenced to Figure Reviewer does not finevald P2 loads on Fig. 5-5.

para. 5-5. See 5-3. Telecon 3/26/09; SIA noted that the P1 and P2 forces are shown on Figure 5-3, but not 5-5 as stated. SIA may revise the reference from Fig. 5-5 to 5-3. The reviewer agrees, and the question on the comment is CLOSED.

403.pg 5-11, g 2.150 million b horizontal earthquake No explanation given, but it may be related to the next-to-last para. load not included in Table 5-2. statement inthe middle of page 5-6, i.e., that the seismic loads are evaluated by use of response spectrum analysis. Telecon 3/26109; SIA confirmed the reviewer's expectation, and the question on the comment is CLOSED.

403 pg 5-12, 1st Dry weight of compressible material Without further explanation use of 8 pcf versus 29 pcf para. between the drywell and concrete for the unit weight of the compressible material appears containment at 8 Ib/cuft is used, and to be un-conservative; wet when applied. Telecon reference is made to 29 Ib/cuft at the 3/26/09; SIA explained that the 29 pcf value is the Becht Nuclear Services

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Civster Creek Drvwell Review Table 2.5 Review:Observations withNo Significance for Levels of Conservatism or Uncertainty spray nozzle. wet material as it is deposited. Itis for historical information and has no effect on the evaluation.

The reviewer agrees and the question on the comment is CLOSED.

403 pg 5-12, 3rd Weight of the air. Itis presumed not to be included in this evaluation, para. since itis identified as an original design test. Telecon 3/26109; SIA explained it is mentioned because it was used in the original calculations, and that it has no effect on the current evaluation. The reviewer agrees and the question on the comment is CLOSED.

403 pg 5-12, 4th 1000 lb live load on weld pads. No basis explicitly provided; presumed to be from para. original design.

403 pg 5-12, last Vent thrust loads/end-cap effect; 2 Load (explicit value) needs to be defined.

para. psi external pressure; hydrostatic pressure due to water not explicitly defined 403 pg 5-13 and Excluding model details for small Reasonable modeling technique for this evaluation 5-14, Section 5.4 nozzles (3.12 in). No Code reinforcement is required implying that local stresses would be low.

Therefore it is not necessaryto model the small nozzle openings.

403 pg 5-13, Use of AD-51O from VIII-Div 2 for Section VIII, Div. 2 is a design-by-analysis code for determining reinforcement Section VIII vessels, and Section III, Subsection NE is requirements for small nozzles. the code being used for evaluation. Itis not clear why VIII-2 is chosen, except for its relationship with the 1962 Section VIII Code, which predates any VIII Div. 2 Code.Section VIII Div. 1 would be more appropriate for that relationship regarding required reinforcement.

111-NE-3330 would be more appropriate for the relationship to the code being used for acceptance criteria for the thinned drywell evaluation. Telecon 3/26/09; SIA confirms the response. The reviewer accepts the explanation, and that it has no affect on the evaluation. The question on the comment is CLOSED.

403 pg 5-13, Vent thrust load "interpretation" The purpose of this statement is unclear, and is 5.3.7 repeated from one page earlier. Telecon 3/26/09; SIA indicated it is to confirm that the load is essentially a boundary condition -- the reviewer agrees, and the question on the comment is CLOSED.

403 pg 5-14, Small number of penetrations Use of the word "provided" implies that there might be Section 5.5. provided with piping loads, more that were not provided.

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Ovster Creek Drvwell Review Table 2.5 '

Review Observations with No Significance for Levels of Conservatism or Uncertainty $

403 pg 5-14 and Jet Forces and Table 5-1. There is no mention of Jet Forces and no reference to pg 5-4 Section Table 5-1 in Section 5.3.3. It is presumed that there 5.3.1.3 should be. Otherwise, the implication is that they have not been considered in the analysis/evaluation.

Telecon 3/26/09; SIA indicated that they have been considered, except for impingement evaluation.

The reviewer agrees and the question on the comment is CLOSED.

403 pg 6-2 Reactor building concrete wall is rigid The reviewer agrees that the assumptions are Section 6.2 (e) compared to the drywell shell. reasonable for the evaluations being performed. The and (f). concrete walls and floors are thicker, but concrete is not as stiff as steel. Nonetheless, the stiffness of the concrete walls and floors is likely much greater than the drywell shell, although there are no calculations to illustrate this.

403 pg 6-2 Not using shell manufacturing Reasonable modeling technique for this evaluation.

Section 6.2 (g) tolerances because measured thickness is used.

403 pg 6-3, 2nd Drywell shell above 11 ft at 150F; Reasonable modeling technique for this evaluation para. concrete below 8 ft 11.25 in. at 70F (assumed); steady-state heat transfer analysis with no conduction to air or concrete.

403 pg 6-4, Star Truss, circumferential closed See Ref. No. 9.

Section 6.3.2. gap boundary conditions 403 pg 6-5 1st 'no displacement" boundary This statement is not clear. It can be understood to line.' condition. mean exactly opposite boundary conditions; 1) fixity of displacements by the phrase "no displacement, i.e.

displacement = 0" or 2) no displacement boundary conditions are applied, i.e. displacements are non-specified "free" solution displacements. Telecon 3126/09; SIA confirmed the reviewer's presumption that no displacement boundary condition was applied, and the question on the comment is CLOSED.

403 pg 6-5 Vent header boundary conditions - The reviewer agrees that this boundary condition is Section 6.3.3. vertical restraint and lateral freedom, appropriate, and insignificantly conservative, considering the restraint applied on the bottom head concrete encasement and support skirt.

403; pg 6-7; item Pipe insulation weight not included. Assumed to be so negligible that it does not affect the (e) statement that upper bound loads are considered.

403, pg 6-9; External piping loads applied to pilot Reasonable modeling technique for this evaluation 6.4.3; 2nd para. node at the center of penetrations and weld pad loads applied as distributed force over the weld pad, etc.

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Oyster Creek Drywell Review Table 2.5.

Review Observations with No Significance for Levels of Conservatism or Uncertainty 403, pg 6-9; The moment at the bottom of the Reasonable modeling technique for this evaluation.

6.4.3; 3rd para. pedestal is assumed to transmit through the concrete floor, etc.

403, pg 6-9; The horizontal earthquake load of How does this relate to Section 6.4.8 which states that 6.4.3; last para. 2,150K. a response spectrum analysis is done? Telecon 3/26/09 SIA confirms that the static load is used in the buckling evaluation (Section 8)and the response spectra are used in the stress analysis (Section 7). The reviewer agrees and the question on the comment is CLOSED.

403, pg 6-10, Excluding the top head and bolts Reasonable modeling technique for this evaluation.

Section 6.4.4, from the model for the refueling case.

2nd para.

403, pg 6-10, Refueling loads and Figure 5-5. The reviewer does not find loads mentioned on Fig. 5-Section 6.4.4, 5. The loads are shown on Fig. 6-14.

3rd line.

403, pg 6-10, Flood load as internal pressure as a Reasonable modeling technique for this evaluation.

Section 6.4.5, function of water depth and inclusion both para. of top head and bolts inthe model.

403, pg 6-10, Jet load at three locations and as Reasonable modeling technique for this evaluation.

Section 6.4.6, Level D Conditions.

both para.

403, pg 6-10, Assuming the reactor vessel and Appropriate, i.e., the reactor vessel and the drywell are Section 6.4.7, drywell move together. effectively connected together for considering this type 2nd para. of motion (rotation about the vertical centerline of the reactor/drywell unit) 403, pg 6-11, Calculating mode frequencies without Reasonable modeling technique for this evaluation.

section 6.4.8, 1st the downcomers.

para, last sentence.

403, pg 6-12, 1st Mass from inside water volume Reasonable modeling technique for this evaluation.

para (continued added to shell model density. The word "estimated" inthe 2nd para. would be better from previous stated as "calculated" to avoid the implication of page). And 2nd inaccuracy.

and 3rd paras.

403, pg 6-12, 4th Flooded volume 80% of the drywell Reasonable modeling technique for this evaluation.

and 5th para. volume and not used for normal The word "estimate" in the 3rd para. would be better operating and refueling conditions. stated as "calculation" to avoid the implication of inaccuracy.

403, pg 6-12, E-W and N-S spectrum analysis and Appropriate.

last para. Rosenbluth Correlation Coefficient for closely spaced modes per NRC RG 1.92.

403, pg 6-12, Single-point spectrum analysis Reasonable modeling technique for this evaluation.

next-to-last para. performed.

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Oyster Creek Drywell Review 403, pg 6-13, first para.

403, pg 6-13, Overall membrane as "highly The reviewer understands what is meant, but notes that section 6.5.1.1, localized" and shown in Fig. 6-15. itcannot be associated with the "general primary 1st para. membrane stress" as defined in ASME Section III Codes. The highly localized area is not evident inFig.

6-15, and is presumed to be 17,080 psi, the maximum stress intensity shown in the stress color spectrum in Fig. 6-15. Itwould be helpful to show the location in a focused plot.

403, pp 6-13, Description and discussion of results (a)" ...thinned bay regions have high stress." The section 6.5.1. for pressure loading in Figures 6-15 reviewer understands what is meant, but notes that it and 6-16. would be clearer to state that "the thinned regions show the highest stress intensity (43,146 psi)." (b)The high stress intensity locations are not evident in Figs. 6-15(b) and (c), and a focused plot would be useful to show the described location. [17080; 45146; 43024 psi] internal and [806; 1915; 1906 psi] external 403, pg 6-14, Description and discussion of results Similar comment regarding showing the high stress section 6.5.2. for steady state thermal loading in intensity locations in Fig. 6-18 and 6-19. The statement Figures 6-17 through 6-19. about disregarding the stresses inthe vent header is appropriate since they have no bearing on the analysis of the drywell shell, i.e., the vent header assemblies are modeled only for boundary conditions for the drywell.

[24192; 45463; 48757 psi].

403, pg 6-14, Description and discussion of results Similar comment regarding showing the high stress section 6.5.3 for gravity loading in Figure 6-20. intensity locations in Fig. 6-20. [8340; 20138; 15949 psi].

403, pg 6-14, Description and discussion of An explanation of where the loads are applied for Fig.

section 6.5.4 application of mechanical and live 6-21 would be useful to support descriptions in Section loading in Figures 6-21 and 6-22. 5 for P1 through P9 (Table 5-2). Similar comment regarding showing the high stress intensity locations in Fig. 6-22. [26147; 27093; 25226 psi]

403, pg 6-15, Description and discussion of results Similar comment regarding showing the high stress section 6.5.5 for refueling loading in Figure 6-23. intensity locations in Fig. 6-23. [18924; 21546; 19817 psi]

403, pg 6-15, Description and discussion of Similar comment regarding showing the high stress section 6.5.6 flooding water pressure load and intensity locations in Fig. 6-25. [30021; 41033; 37932 results in Figures 6-24 and 6-25. psi]

403, pg 6-15, Description and discussion of OBE Similar comment regarding showing the high stress section 6.5.7 Seismic Anchor Movements results in intensity locations in Fig. 6-26. [5172; 5492; 4952 psi].

Figure 6-26. The use of the words "maximum stress" and "high stress" that identify two locations could be more accurately stated as "the highest stresses occur in the star truss component where the anchor movement was applied and at the bottom of the drywell." The reviewer recommends eliminating "the cantilever effect" as a Becht Nuclear Services

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17693-R-001 Rev. 0 (4/6/2009) NJIDEP Ovster Creek Drvwell Review Table .2.5 - :" . . *  ; -

Review.Observationswi-th No Significance for.Levels of Con.ervatism or Uncertainty potentially confusing way of explaining where maximum stresses occur where they do in this case.

403, pg 6-17, Refueling configuration. Response Figures 6-27, 6-28, 6-29 and 6-30 show the "middle" section 6.5.8.2.1. Spectrum Analysis results; stresses. stress intensities which are therefore membrane stress intensities. Therefore the "stress intensity" wording in that paragraph is presumed to mean "membrane stress intensity." Similarly; section 6.5.8.2.2 for Figures 6-31, 6-32, 6-33 and 6-34. [1195; 830; 1226; 1523 psi] and

[40057; 52895; 10036; 68350 psi]

403, pg 6-18, Stress Intensity results for external Figure 6-36 shows the "middle" stress intensities which section 6.5.10 piping SSE loads, are therefore membrane stress intensities. Therefore the "stress intensity" wording in that paragraph is presumed to mean "membrane stress intensity."

[50507 psi]

403, pg 6-18, Stress Intensity results for external Figure 6-37 shows the "middle" stress intensities which section 6.5.11 piping thermal loads, are therefore membrane stress intensities. Therefore the "stress intensity" wording in that paragraph is presumed to be "membrane stress intensity." [8022 psi]

403, pg 6-18, Stress Intensity results for flooding Figure 6-38 shows the "middle" stress intensities which section 6.5.12 SSE seismic anchor movement are therefore membrane stress intensities. Therefore loads, the "stress" wording in that paragraph should be "membrane stress intensity." [9815 psi]

403, pg 6-18, Stress Intensity results for external Figure 6-35 shows the "middle" stress intensities which section 6.5.9 piping OBE loads, are therefore membrane stress intensities. Therefore the "stress intensity" wording in that paragraph is presumed to mean "membrane stress intensity."

[25247 psi]

403, pg 6-20, Suggested Pipe Support Spacing. The word "suggested" is presumed to mean Table 6-2 "enveloping" since the piping attachment loads are conservatively calculated rather than taken from as-built/installed equipment data.

403, pg 6-22, Penetration Valve Weights The word "considered" in note (2)is presumed to mean Table 6-4 "applicable" The word "considered" implies something was not included that should have been.

403, pg 7-2, Algebraic sum of individual load Itis presumed that the unsigned SRSS seismic section 7.3, 1st cases. stresses from the response spectra analyses are para. appropriately handled regarding combination with "signed" stresses.

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17693-R-001 Rev. 0(4/6/2009) NJDEP Oyster Creek Drvwell Review Table 2.5 Review Observations with No Significance for Levels of Conservatism or Uncertainty 403, pg 7-2, Refueling and post-accident flooding The basis for considering these cases as the governing section 7.3, 2nd conditions load combinations are cases is from the old analyses - original Parsons para. "considered" to be governing cases. Report the FSAR, Update 7 and GE. This seems reasonable. The Sandia analysis considers one other case - the accident case, which exhibits higher overall stresses but lower compressive stresses, and is therefore not evaluated for buckling. That is the reviewer's presumption.

403, pg 7-3, 1st Effect of jet loads (LOCA) and that jet The statement that jet loads are not evaluated inthis para. loads are not evaluated in this report. report appears to contradict the information on loads in Section 6, particularly Case 9 of Table 6-1 and in supporting wording inSection 6.4.6. Telecon 3126109; SIA indicated that the jet loads are included in non-controlling load cases, and that impingement is not evaluated. The reviewer agrees and the question on the comment is CLOSED.

403, pg 7-3, Penetrations inthe suppression The reviewer acknowledges that they are not included next-to-last para. chamber .. Are not included ... because they are not in the scope of the evaluation.

403, pg 7-4, 1st Bolts and pins not being included in Not modeling bolts and pins is not the reason for not line. the evaluation because they are not evaluating them. Itwould be better to state that they modeled, and bolt preloads are not are not in the scope of the evaluation.

considered.

403, pg 7-5, Fatigue evaluation exemption. The reviewer concurs that the NE-3221.5(d) conditions section 7.5 are met. However, the thinned corroded areas are likely areas of stress concentration, in addition to being areas of lower general strength. Therefore, the reviewer presumes that SIA just did not consider it necessary to discuss this aspect perhaps because NE's fatigue exemption is silent on the level of total stress.

403, pg 7-6, 1st The discussion on the results of the The 855 pressure cycles being more than sufficient is para. fatigue exemption listed in Table 7- based on the assumed 200 cycles. That is all that

11. needs to be stated. The reviewer understands the last statement regarding 135 ksi and the 3Smrlimit, but the way itis worded can appear unconservative, at least at first reading.

403, pg 7-7 Reconciliation of codes; 1962 Edition The mention of the use of Section VIII Div. 2 in Section of Section VIII and 5.4 (page 5-13) should be added.

case/interpretations 1270N, 1271N 1272N-5 and others.

403, pg 7-1, Use of ASME Section III, Subsection This code edition and addenda are noted to be the Section 7.1 2nd NE, 1989 with 1991 Winter Addenda "code of record" for Oyster Creek. Since this para. evaluation is for life extension, it may be more appropriate to use a later edition, at least as currently permitted by NRC. However, the reviewer believes there is not likely any significant differences with later Becht Nuclear Services

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Ovster Creek Drvwell Review Table 2. -

Review Observationswith No Significance for Levels of Conservatism or Uncertainty editions of Subsection NE.

403, pg 7-1, Stress Intensity Allowables. The reviewer presumes that there is an unstated Section 7.2 1st assumption that the potential for decreased strength para. (yield, ultimate, etc.) of the drywell shell material as from irradiation, ifany, is negligible.

403, pg 7-14 Copies of Stress Classification These tables from the 1989MW91 version of Subsection Guidance Tables from NE. NE compare closely and appropriately to the 2007 edition of NE 403, pg 7-15, Table 7-6 Load Combinations and The Thrml load case listed in Table 6-1 is not included Table 7-6 relationship to the load cases listed in inany of the load combinations listed inTable 7-6.

Table 6-1. Telecon 3/26/09; SIA statedthat Thrml is likely considered in a load case that did not control. SIA will confirm. 3/27/09 written response: QI: The Load Combinations in Report No. 0006004.403, Rev. 1 [1], Table 7-6 includes the term Thrm2 but does not include Thrml. Please explain why there is no Thrml in the load combinations. Response:

Per Table 6-1 of the report [1], Thrml refers to the accident condition temperature. Per FSAR Section 3.8.2.3 (c) (5)[2], the load combination for the accident condition includes the accident condition temperature, Thmrl. The Accident Condition load combination was determined to not be one of the limiting load combinations and therefore was not evaluated in detail. The question on the comment is CLOSED.

403, pg 7-20, Evaluation of Fatigue Analysis Table 7-11 does not show SA-516 Gr 70 and Gr 60, Table 7-11 exemption for Subsection NE for which is the material applicable to the evaluations in various materials. Section 7. Itis presumed that since A-212 is no longer a listed material inASME Section IIPart D,that SA-516 and its 70 and 60 ksi grades are the equivalents. SIA uses 29 mpsi for E and Sandia uses 29.5 mpsi - an insignificant difference for this evaluation.

403 pg 8-3, Use of Miller's modified capacity Reduction of Conservatism of the capacity reduction section 8.3.1, 1st reduction factor ("CRF") factors for the "presence of tensile hoop stress is not para. addressed in N-284-1, but its use is permitted as long as it isjustified in the Design Report. The reviewer considers the inclusion of the 403 Report references

[23] and [26] as valid justification.

403, pg 8-7, Use of g loads from the response Acknowledged as appropriate.

section 8.6, 1st spectrum at the significant mode.

Para.

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Oyster Creek Drvwell Review iR---n-ý'cý,'rvtinsýwthNoS~i-g'ni-fi'c~aný-c.ef',Lv oroeW i 403, pg 8-7, Boundary conditions are "similar" to Acknowledged as appropriate without the report section 8.6, 2nd the structural displacement used in describing what is "similar" instead of "the same."

para. the stress analysis.

403, pg 8-8, 2nd The "average" CRF of the thin areas. The average CRF of the thin areas is for information, para. and not for comparison to allowable buckling criteria.

403, pg 8-10, Use of N-284-1 and Miller Modified Reduction of Conservatism of the capacity reduction' section 8.8.1, 1st Capacity Reduction Factor (CRF) factors for the "presence of tensile hoop stress is not and 2nd paras. addressed in N-284-1, but its use is permitted as long as it is justified in the Design Report. The reviewer considers the inclusion of the 403 Report references

[231 and [26] as valid justification.

403, pg 8-11, 3rd The use of the spherical shell based The cited reference indicates that the spherical shell-and 4th paras. CRF for the cylindrical portion of the based equations are applicable to the cylindrical shell drywell. of the drywell.

404, pg 4-2, 2nd The use of a solid element submodel This technique is appropriate.

and 3rd para. and linearization of stresses to obtain PL + Pb stresses.

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17693-R-001 Rev. 0 (4/6/2009) NJDEP Oyster Creek Drvwell Review Appendix C Editorial Comments Associated with Technical Content (non-technical editorials are not provided) 403 Report pg 5-13, last line Table 5-5 is not mentioned in the text.

and following onto pg 5-14.

403 Report pg 5-15, Section Editorial: 82'-9' should be 82'-9" (9 inches, not 9 feet).

5.7.1.1, 4th line.

403 Report pg 5-18, Section Reference 18 is 20.

5.7.2.2, 1st line.

403; pg 6-8. Editorials; (a) 3rd para, 2nd line "on" should be "in"or "for." (b)The reference to Table 6-5 in para. 2, line 2 should be Table 6-3.

403, pg 6-10, Section 6.4.4, Loads are not shown on Fig. 5-5; they are shown on Fig. 5-3.

3rd line.

403, pg 6-15/6-16, section Editorials; (a) last para, 1st sentence: "mode frequency" should be "modal 6.5.8 frequency." -- occurs other places, as well. (b)pg 6-16, "excluded in" should be "excluded from."

403, pg 6-17, section 6.5.8.2.1. Editorial: middle of each para of sections 6.5.8.2.2, the word "due" is apparently missing before "to" 403, pg 7-4, item (c) Editorial: "Bending stress" 403, pg 7-6, 1st para. Editorial: 1st line, "materials existed" should be "materials that existed".

403, pg 7-14 Editorial: Page 7-14, the top line inthe table is missing.

403, pg 7-15, Table 7-6 Editorial: SAM(SSE) listed inTab le 7-6 is designated as "SSESAM" in Table 6-1.

403, pg 8-2, Eqn 8-2 Editorial: alpha, a 403 pg 8-4, section 8.3.2, 1st Editorial: "capacitor" should be "capacity".

para.

403, pg 8-10, Section 8.8.1, 1st Editorial: Reference 6 should be 24.

para.

404, pg 4-2, 2nd and 3rd para. Editorial: "Pi' should be "PL" here and in other places in the 404 report.

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