ML092940241
| ML092940241 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 10/19/2009 |
| From: | Murillo R Entergy Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| W3-1SI-015, W3F1-2009-0056 | |
| Download: ML092940241 (11) | |
Text
Entergy Operations, Inc.17265 River Road Killona, LA 70057-3093 Tel 504-739-6715 Fax 504-739-6698 rmurill@entergy.com Robert J. Murillo Licensing Manager Waterford 3 W3F1-2009-0056 October 19, 2009 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001
SUBJECT:
Request for Alternative W3-1SI-01 5, Inspection of Reactor Vessel Head In-Core Instrument Nozzles during Third Ten-Year Inservice Inspection Interval Waterford Steam Electric Station, Unit 3 Docket No. 50-382 License No. NPF-38
Dear Sir or Madam:
Pursuant to 10 CFR 50.55a(a)(3)(ii), Entergy Operations, Inc (Entergy) requests relief from the inspection requirements of American Society of Mechanical Engineers (ASME) Code Case N-729-1, as conditioned by 1 OCFR50.55a(g)(6)(ii)(D), for Waterford 3 Steam Electric Station, Unit 3 (Waterford
- 3) for-the third 10-year inservice inspection (ISI) interval.As published in the Federal Register on September 10, 2008, NRC revised 1OCFR50.55a to, in part, supersede the NRC First Revised Order EA-03-009 by referencing ASME Code Case N-729-1, as conditioned by 10 CFR50.55a(g)(6)(ii)(D).
In addition, this revision to 10CFR50.55a requires that following September 1, 2009, ultrasonic testing (UT) examinations be performed using qualified personnel, procedures, and equipment.
Compliance to this requirement was not achieved in time to support the Waterford 3 fall 2009 refueling outage. As discussed in the attached relief request (Attachment 1), inspection of the reactor pressure vessel (RPV) head In-Core Instrumentation (ICI) penetrations in accordance with the revised rule for performing surface examinations would constitute a hardship.
Entergy proposes to perform an alternate examination which will reduce or eliminate this hardship due to high personnel dose., Entergy will be replacing the Waterford 3 RPV head during the 1 7 th refueling outage which will commence in the spring of 2011.Entergy requests approval of the attached alternative W3-1SI-01 5 by November 6, 2009 because the RPV head inspections are scheduled to be completed by then. This request is also to support the return to service of Waterford 3 from the fall 2009 refueling outage.This letter contains new commitments as provided in Attachment 2.r W3F1-2009-0056 Page 2 If you have any questions or require additional information, please contact me at 504-739-6715.Sincerely, RJM/RJP Attachments:
- 1. Request for Alternative W3-ISI-01 5, Inspection of Reactor Vessel Head In-Core Instrument Nozzles during Third Ten-Year Inservice Inspection Interval 2. List of Regulatory Commitments W3F1-2009-0056 Page 3 cc: Mr. Elmo E. Collins, Jr.Regional Administrator U. S. Nuclear Regulatory Commission Region IV 612 E. Lamar Blvd., Suite 400 Arlington, TX 76011-4125 NRC Senior Resident Inspector Waterford Steam Electric Station Unit 3 P.O. Box 822 Killona, LA 70066-0751 U. S. Nuclear Regulatory Commission Attn: Mr. N. Kalyanam Mail Stop O-07D1 Washington, DC 20555-0001 Wise, Carter, Child & Caraway ATTN: J. Smith P.O. Box 651 Jackson, MS 39205 Winston & Strawn ATTN: N.S. Reynolds 1700 K Street, NW Washington, DC 20006-3817 Morgan, Lewis & Bockius LLP ATTN: T.C. Poindexter 1111 Pennsylvania Avenue, NW Washington, DC 20004 Louisiana Department of Environmental Quality Office of Environmental Compliance Surveillance Division P. O. Box 4312 Baton Rouge, LA 70821-4312 American Nuclear Insurers Attn: Library 95 Glastonbury Blvd.Suite 300 Glastonbury, CT 06033-4443
-N Attachment I to W3F1-2009-0056 Request for Alternative W3-ISI-01 5, Inspection of Reactor Vessel Head In-Core Instrument Nozzles During Third Ten-Year Inservice Inspection Interval Attachment 1 to W3F1-2009-0056 Page 1 of 5 Entergy Operations, Inc.Waterford Steam Electric Station, Unit 3 Request For Alternative W3-SI-01 5, Inspection of Reactor Vessel Head In-Core Instrument Nozzles During Third Ten-Year Inservice Inspection Interval 1. ASME CODE COMPONENT AFFECTED Waterford Steam Electric Station, Unit 3 (Waterford
- 3) has one hundred-two (102) ASME Class 1 reactor pressure vessel (RPV) head penetration nozzles comprised of ninety-one (91) Control Element Drive Mechanism (CEDM) nozzles, ten (10) In-Core Instrument (ICI)nozzles, and one (1) vent line nozzle. This request pertains to the ICI nozzles only.Component Numbers: Ten (10) RPV Head ICI Nozzles [02-T-92 through 02-T-101]Code
References:
(1) ASME Section XI 2001 Edition through 2003 Addenda (2) ASME Code Case N-729-1, as conditioned by 1 OCFR50.55a(g)(6)(ii)(D)
Examination Category:
Code Case N-729-1 in lieu of Table IWB-2500-1 Exam Category B--P Item Number:, B4.20
Description:
Proposed Alternative to Table 1 of ASME Code Case N-729-1 as conditioned by 10CFR50.55a(g)(6)(ii)(D)
Unit/Inspection Waterford 3 / Third (3 rd) 10-year inspection interval Interval Applicability:
May 31, 2008 thru July 2017 I1. APPLICABLE CODE REQUIREMENT The Code of Federal Regulations (Rule) 10CFR50.55a(g)(6)(ii)(D)(3) requires: Instead of the specified
'examination method' requirements for volumetric and surface examinations in Note 6 of Table 1 of Code Case N-729-1, the licensee shall perform volumetric and/or surface examination of essentially 100 percent of the required volume or equivalent surfaces of the nozzle tube, as identified by Figure 2 of ASME Code Case N-729-1. A demonstrated volumetric or surface leak path assessment, through all J-groove welds shall be performed.
If a surface examination is being substituted for a volumetric examination on a portion of a penetration nozzle that is below the toe of the J-groove weld [Point E on Figure 2 of ASME Code Case N-729-1], the surface examination shall be of the inside and outside wetted surface of the penetration nozzle not examined volumetrically.
Code Case N-729-1 (Reference
- 1) requires that components shall be examined as specified in Table 1 of the code case.
Attachment 1 to W3F1-2009-0056 Page 2 of 5 III. REASON FOR REQUEST Pursuant to 1 OCFR50.55a(a)(3)(ii), Entergy Operations, Inc (Entergy) requests an alternative to the requirements of Code Case N-729-1 as conditioned by 1OCFR50.55a(g)(6)(ii)(D) for the fall 2009 Waterford 3 refueling outage.Prior to the Rule change, Entergy Operations, Inc. (Entergy) performed volumetric examination of the ICI nozzle tube and a leak path assessment of the J-groove welds in accordance with NRC First Revised Order EA-03-009 (Reference 2). These examinations were not qualified to requirements of paragraph 10CFR50.55a(g)(6)(ii)(D).
In addition, Entergy supplemented these base examinations with automated eddy current examination (ECT) of the inside diameter (ID) and lower nozzle end penetration surfaces.Volumetric examination of the CEDM nozzles and J-groove weld leak path assessment techniques have been successfully demonstrated at the Electric Power Research Institute (EPRI). However, qualification of volumetric examination techniques in accordance with 1OCFR50.55a(g)(6)(ii)(D)(4) for inspection of ICI nozzle tubes was not successful.
As a result, compliance with current regulations requires leak path assessment of the ICI J-groove weld and surface examination of the required exam volume on the ICI nozzle tube inside and outside wetted surfaces.Entergy will perform a demonstrated leak path assessment of all ICI J-groove welds and remote ECT examination of the ICI penetration inside and lower end surfaces.
Entergy -will also perform a bare metal visual (BMV) inspection of the RPV head surface in accordance with Code Case N-729-1 during RF16. However, examination of the ICI nozzle tube outer surface below the J-groove weld cannot be performed remotely, which introduces a radiological hardship.
In order to maintain radiological dose as low as reasonably achievable, Entergy proposes to perform an alternative examination such that examination of the ICI nozzle tube OD wetted surface would not provide a compensating increase in the level of component quality and public safety.The ICI penetration
'tube OD wetted surface is formed by a short extension of the tube below the J-groove weld. The length of this extension varies azimuthally around the penetration and from one penetration to another. These variations were introduced by tolerances in allowable J-groove weld reinforcement during original fabrication.
'Dimensional variations and the elliptical cross-section which results from conforming the lower end to the spherical head surface has impeded development of remotely controlled examinations.
Manually delivered ECT examination of the nozzle tube outside diameter (OD) would have to be performed using a hand held transducer.
The estimated extension of Waterford 3 nozzle tubes below the ICI J-groove weld is approximately 1-inch. Surface coverage in accordance with Code Case N-729-1 as conditioned by 1OCFR50.55a(g)(6)(ii)(D) would require under head manual delivery for the ICI nozzle penetrations not receiving essentially 100% coverage.
New ECT tooling is being developed by Wesdyne which contains a larger probe head that, if required, would be used to perform manual scanning of the ICI nozzle OD. However, Entergy does not have historical experience with its use in the field and its confirmed effectiveness to limit the number of nozzle scans. Additionally, the Waterford 3 head stand is elevated such that manual delivery would require additional time for accessing the ICI nozzle OD. Entergy has estimated the total personnel dose for Attachment 1 to W3F1T-2009-0056 Page 3 of 5 performing these manual OD nozzle scans to be between 1.0 to 3.0 Rem. Liquid penetrant examination of the same surfaces would be expected to result in significantly larger personnel exposures.
IV. PROPOSED ALTERNATIVE AND BASIS FOR USE Proposed Alternative Entergy proposes to remotely perform a demonstrated volumetric ICI J-groove weld leak path assessment, ECT surface examination of the interior diameter (ID) and bottom face surface of each ICI nozzle, and a BMV inspection of the RPV head in accordance with Code Case N-729-1. The required examination of the ICI penetration tube OD surface will not be performed.
Entergy proposes to supplement the ECT examinations by performance of a volumetric examination of the ICI nozzle tube using UT equipment and techniques demonstrated under the NRC First-Revised Order EA-03-009 from 1 inch above the J-groove weld to the detectable extent of the nozzle tube below the J-groove weld. Improvements in data acquisition and analysis that were developed during qualification of Control Element Drive Mechanism (CEDM) volumetric examinations will be incorporated in the proposed ICI examinations.
The proposed alternate volumetric examination will include Time-of-Flight-Diffraction (TOFD) examination from the ID surface and from the lower end surface similar to the areas previously examined under NRC First-Revised Order- EA-03-009.
As described in the Basis below, examination of essentially 100% of the penetration tube volume extending downward from the J-groove weld root to one inch below the J-groove weld root is necessary for ensuring quality and the reactor coolant system (RCS) pressure boundary are not compromised.
Therefore, UT TOFD data collected will be reviewed for ,consistency with current data quality standards to ensure exam quality. If the TOFD data is determined to have unacceptable quality from the root of the J-groove weld to 1 inch below the root of the J-groove weld, then a manually delivered ECT examination of the ICI penetration tube OD surface will be performed.
As a result, this will comply with Code Case N-729-1, as conditioned by 10CFR50.55a(g)(6)(ii)(D).
UT technology and tooling for examination of CEDMs and ICI penetration tubes are essentially the same. A significant difference between successful qualification of CEDM and ICI volumetric examination techniques appears to be due to misalignment of the open housing probe as a result of insufficient guide cone engagement and not applying the laser alignment process used by the Waterford 3 vendor. Additionally, penetration geometry and the effects of weld induced distortion in low restraint areas of the lower end of the ICI penetrations likely contributed to the failure to gain examination qualification.
Tooling used at Waterford uses complete alignment techniques and the Waterford ICI nozzles have not experienced significant data quality concerns as a result of nozzle tube weld induced distortion.
Therefore, UT data obtained during RF16 is expected to compare favorably with previous outage data. Despite the inability to qualify volumetric examination of ICI penetrations in support of Waterford 3's fall 2009 refueling outage examinations, those techniques remain capable of detecting defects when quality UT data is obtained.
Attachment 1 to W3F1-2009-0056 Page 4 of 5 Basis for Proposed Alternate Examination Coveraqe The short extension of the ICI penetration below the J-groove weld has no structural function and cracks that are confined to this volume have no significance to quality or pressure boundary integrity.
For PWSCC to develop into a RCS pressure boundary defect, a crack must grow upward through the penetration volume adjacent to the J-groove weld and extend above it, or it must grow through the J-groove weld itself. The risk of PWSCC within the J-groove weld is managed at Waterford 3 by using demonstrated leak path assessment examinations in accordance with 10CFR50.55(a).
The time required for a throughwall, axial crack to grow from the bottom of an ICI penetration tube upward to reach the root of the J-groove weld has been calculated using finite element flaw tolerance methodologies documented in WCAP-1 5815, Revision 1 (Reference 3). This report has not been provided to the NRC; however, the approach of this report is similar to that provided in WCAP-1 5819 for the San Onofre Nuclear Generating Station (Reference 4). Based on WCAP-1 5815, Revision 1, the limiting case for an axial flaw, located in the nozzle tube at the toe of the J-groove weld, to grow to the root of the weld (approximately 1 inch) would take in excess of one operating cycle.Surface examinations of the ID and bottom end of the penetration preclude the possibility of throughwall cracks. Therefore, the throughwall crack growth rates assumed in this analysis conservatively bound potential crack growth. Circumferentially oriented PWSCC cracking below the J-groove weld does not pose an RCS pressure boundary concern since they are not projected to grow into the J-groove weld. A complete severance of the nozzle tube would have to occur for a loose part to be displaced.
The ID ECT scan will be able to detect any throughwall flaws.Although EPRI qualification of the volumetric examination techniques proposed for ICI penetrations were unsuccessful, previous exam data quality for ICI J-groove welds has proven to be effective for the Waterford 3 ICI nozzle examinations.
The qualifications performed at EPRI for CEDM volumetric examinations identified improvements to the previous examination techniques.
Entergy proposes to perform volumetric examination of ICI penetrations incorporating technique improvements developed for CEDMs. These examinations will reduce the possibility of undetected PWSCC. All acceptable UT data produced during the proposed supplemental examinations will be analyzed for indication of defects.The proposed alternatives will minimize the radiological consequence of examinations at Waterford 3 to as low as reasonably achievable while proViding confirmation that the structural integrity of the ICI nozzle tube is acceptable.
In addition to the proposed alternate and compensatory examinations, Waterford 3 has implemented a program for enhanced monitQring of RCS leakage consistent with the September 2006 Pressurized Water Reactor Owners Group industry initiatives.
This leakage monitoring program is designed to detect and respond to increased RCS leakage at levels well below Technical Specification limits.Therefore, use of manual surface examination of the OD to determine the pressure boundary integrity of the Waterford 3 ICI nozzles would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety. Pursuant to 10 CFR 50..55a(a)(3)(ii), Entergy requests an alternative to the requirements of Code Attachment 1 to W3F17-2009-0056 Page 5 of 5 Case N-729-1 as conditioned by 10CFR50.55a(g)(6)(ii)(Q) for the fall 2009 Waterford 3 refueling outage.V. DURATION OF PROPOSED ALTERNATIVE The proposed alternative will apply to the existing RPV head for the fall 2009 (RF16)Waterford 3 refueling outage ICr examinations.
Entergy will be replacing the RPV head during the spring 2011 refueling outage.VI. PRECEDENT A similar alternative was requested by Southern California Edison for San Onofre Nuclear Generating Station, Units 2 and 3 on October 2, 2009 (Reference 4).VII. REFERENCES
- 1. ASME Code Case N-729-1, "Alternative Examination Requirements for PWR Reactor Vessel Upper Heads With Nozzles Having Pressure-Retaining Partial-Penetration Welds,Section XI, Division 1", Approved March 28, 2006.2. First Revised NRC Order (EA-03-009)
Establishing Interim Inspection Requirements for Reactor Pressure Vessel Heads at Pressurized Water Reactors, issued on February 20, 2004 [ML040220181].
- 3. WCAP-1 5815, Revision 1, "Structural Integrity Evaluation of Reactor Vessel Upper Head Penetrations to Support Continued Operation:
Waterford Unit 3 and ANO Unit 2" dated March 2002 4. Southern California Edison letter to the NRC dated October 2, 2009, "Third Ten-Year Inservice Inspection (ISI) Interval Relief Request ISI-3-30, Inspection of Reactor Vessel Head Incore Instrument Nozzles, San Onofre Nuclear Generating Station, Units 2 and 3."
Attachment 2 to W3F1-2009-0056 List of Regulatory Commitments Attachment 2 to W3F1-2009-0056.Page 1 of I List of Regulatory Commitments The following table identifies those actions committed to by Entergy in this document.
Any other statements in'this submittal are provided for information purposes and are not considered to be regulatory commitments.
TYPE SCHEDULED COMPLETION DATE COMMITMENT (Check one)(If Required)ONE-TIME CONTINUING ACTION COMPLIANCE Entergy will perform eddy current X examinations of the inside diameter and the nozzle tube lower face in accordance with Fall, 2009 Refueling Code Case N-729-1 as conditioned by Outage 10CFR50.55a(g)(6)(ii)(D).
Entergy will also acquire and analyze ICI ultrasonic data .., , from 1 inch above.the J-groove weld to the detectable extent of the nozzle tube below the J-groove weld. (Improvements in data acquisition and analysis that were developed during qualification of CEDM volumetric examinations will be incorporated in the proposed ICI examinations).
If ultrasonic (TOFD) data is determined to X Fall 2009 Refueling have unacceptable quality in the nozzle Outage tube from the root of the J-groove weld to 1 inch below the root of the J-groove weld, then a manually delivered eddy current examination of the ICI penetration tube OD surface will be performed.