ML19301A905
| ML19301A905 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 10/30/2019 |
| From: | Siva Lingam Plant Licensing Branch IV |
| To: | Bement R Arizona Public Service Co |
| Lingam S, 301-415-1564 | |
| References | |
| EPID L-2018-LLA-0194, EPID L-2018-LLE-0010 | |
| Download: ML19301A905 (9) | |
Text
October 30, 2019 Mr. Robert S. Bement Executive Vice President Nuclear/
Chief Nuclear Officer Mail Station 7602 Arizona Public Service Company P.O. Box 52034 Phoenix, AZ 85072-2034
SUBJECT:
PALO VERDE NUCLEAR GENERATING STATION, UNITS 1, 2, AND 3 - THIRD REGULATORY AUDIT PLAN FOR NOVEMBER 7-8, 2019, IN SUPPORT OF FRAMATOME HIGH THERMAL PERFORMANCE FUEL LICENSE AMENDMENT REQUEST AND EXEMPTION (EPID L-2018-LLA-0194 AND EPID L-2018-LLE-0010)
Dear Mr. Bement:
By letter dated July 6, 2018 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML18187A417), as supplemented by letters dated October 18, 2018, March 1, 2019, May 17, 2019, and October 4, 2019 (ADAMS Accession Nos. ML18296A466, ML19060A298, ML19137A118, and ML19277J457, respectively), Arizona Public Service Company (the licensee) requested changes to the technical specifications to support the implementation of Framatome Advanced Combustion Engineering 16x16 High Thermal Performance fuel design with M5 as a fuel rod cladding material and gadolinia as a burnable absorber for Palo Verde Nuclear Generating Station (Palo Verde), Units 1, 2, and 3. In addition to this license amendment request (LAR), the licensee is requesting an exemption from certain requirements of Title 10 of the Code of Federal Regulations (10 CFR) Section 50.46, Acceptance criteria for emergency core cooling systems [ECCS] for light-water nuclear power reactors, and 10 CFR Part 50, Appendix K, ECCS Evaluation Models, to allow the use of Framatome M5 alloy as a fuel cladding material.
This amendment will adapt the approved Palo Verde reload analysis methodology to address both Westinghouse and Framatome fuel, including the implementation of Framatome methodologies, parameters, and correlations. The ability to use either Westinghouse or Framatome fuel will ensure security of the Palo Verde fuel supply by providing for multiple fuel vendors with reliable fuel designs and geographically diverse manufacturing facilities.
For better understanding of the LAR, the U.S. Nuclear Regulatory Commission staff conducted the first audit at the Hilton Hotel, 1750 Rockville Pike, Rockville, Maryland 20852, on January 22-23, 2019. For preparing the final requests for additional information, the second audit was conducted at the plant site in Arizona on June 17-20, 2019, to review all the calculation notebooks and relevant documents. A third audit will be held on November 7-8, 2019, at the Westinghouse facility and Marriott Hotel in Bethesda, Maryland, to review the Westinghouse Palo Verde seismic analysis, loss-of-coolant accident analysis, and some of the licensees responses in its letter dated October 4, 2019. The corresponding regulatory audit plan is enclosed with this letter.
R. Bement If you have any questions, please contact me at 301-415-1564 or via e-mail at Siva.Lingam@nrc.gov.
Sincerely,
/RA/
Siva P. Lingam, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. STN 50-528, STN 50-529, and STN 50-530
Enclosure:
Regulatory Audit Plan cc: Listserv
ML19301A905 NRR-106 OFFICE NRR/DORL/LPL4/PM NRR/DORL/LPL4/LA NRR/DSS/SFNB/BC NAME SLingam PBlechman (JBurkhardt for) RLukes DATE 10/29/19 10/29/19 10/29/19 OFFICE NRR/DSS/SNSB/BC(A)
NRR/DORL/LPL4/BC NRR/DORL/LPL4/PM NAME JBorromeo JDixon-Herrity SLingam DATE 10/30/19 10/30/19 10/30/19
Enclosure REGULATORY AUDIT PLAN FOR NOVEMBER 7-8, 2019 TO SUPPORT REVIEW OF FRAMATOME HIGH THERMAL PERFORMANCE FUEL LICENSE AMENDMENT REQUEST AND EXEMPTION ARIZONA PUBLIC SERVICE COMPANY PALO VERDE NUCLEAR GENERATING STATION, UNITS 1, 2, AND 3 DOCKET NOS. STN 50-528, STN 50-529, AND STN 50-530
1.0 BACKGROUND
The U.S. Nuclear Regulatory Commission (NRC) staff is currently engaged in a review of a license amendment request (LAR) for the Palo Verde Nuclear Generating Station (Palo Verde),
Units 1, 2, and 3. By letter dated July 6, 2018 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML18187A417), as supplemented by letters dated October 18, 2018, March 1, 2019, May 17, 2019, and October 4, 2019 (ADAMS Accession Nos. ML18296A466, ML19060A298, ML19137A118, and ML19277J457, respectively), Arizona Public Service Company (APS, the licensee) requested changes to the technical specifications (TSs) to support the implementation of Framatome Advanced Combustion Engineering (CE) 16x16 High Thermal Performance (HTP') fuel design with M5 as a fuel rod cladding material and gadolinia as a burnable absorber for Palo Verde, Units 1, 2, and 3. In addition to this LAR, the licensee is requesting an exemption from certain requirements of Title 10 of the Code of Federal Regulations (10 CFR) Section 50.46, Acceptance criteria for emergency core cooling systems [ECCS] for light-water nuclear power reactors, and 10 CFR Part 50, Appendix K, ECCS Evaluation Models, to allow the use of Framatome M5 alloy as a fuel cladding material. Further, the proposed amendment would revise TS 2.1.1, Reactor Core SLs [Safety Limits]; TS 4.2.1, Fuel Assemblies; and TS 5.6.5, Core Operating Limits Report (COLR).
This amendment will adapt the approved Palo Verde reload analysis methodology to address both Westinghouse and Framatome fuel, including the implementation of Framatome methodologies, parameters, and correlations. The ability to use either Westinghouse or Framatome fuel will ensure security of the Palo Verde fuel supply by providing for multiple fuel vendors with reliable fuel designs and geographically diverse manufacturing facilities.
The NRC staff conducted a regulatory audit on January 22-23, 2019 (ADAMS Accession No. ML19011A108), to enhance technical understanding of the submitted documentation.
During this audit, the licensee made presentations in support of the LAR (ADAMS Accession No. ML19060A298). This audit helped the NRC staff to better understand the supporting documentation and analysis results through interaction with APSs technical experts and also helped to prepare the NRC staffs draft requests for additional information (RAIs). The NRC staff conducted another audit at the Palo Verde site in Arizona, on June 17-20, 2019 (ADAMS Accession No. ML19154A469), to review all the calculation notebooks and relevant documents related to the LAR. This site audit helped the NRC staff to prepare the final RAIs. The final RAIs were issued on August 29, 2019 (ADAMS Accession No. ML19234A320), and the licensee provided the RAI responses on October 4, 2019. The proposed third audit will be held in
accordance with the Office of Nuclear Reactor Regulation (NRR) Office Instruction LIC-111, Regulatory Audits, dated December 16, 2008 (ADAMS Accession No. ML082900195).
2.0 REGULATORY AUDIT SCOPE The NRC staff would like the licensee to make available the appropriate staff with detailed knowledge of the Palo Verde licensing basis and the submitted LAR, supporting methodology, and supporting documents used in the development of the LAR.
The scope of this third regulatory audit includes a detailed discussion of the LAR, with focus on items discussed in Section 3.0, Information Needs, of this audit plan with the appropriate licensee or its contractor staff. During this audit, the NRC staff intends to review the Westinghouse seismic analysis, loss-of-coolant accident (LOCA) analysis, and RAIs BHTP RAI-03, BHTP RAI-05, BHTP RAI-06 and CHF RAI-04, SNPB RAI-10, SNPB RAI-17, SNPB RAI-19, SNPB RAI-22, SNPB RAI-25, SNPB RAI-26, SNPB RAI-28, SNPB RAI-29, SNPB RAI-30, and SRXB RAI-3. In particular, RAIs SNPB RAI-10, SNPB RAI-17, SNPB RAI-28, SNPB RAI-29, and SNPB RAI-30 are related to Westinghouse seismic and LOCA analyses.
3.0 INFORMATION NEEDS The licensee is requested to have the presentations and documents related to the areas of focus listed below. The documentation could be provided by presentations, documents, and calculation details. The following are the planned major areas of focus for detailed discussion and document review. Additional information needs to be identified during the audit and will be communicated to the designated point of contact.
The deliberations during the audit, along with the original contents of the LAR as well as the supplemental information, are used to prepare the safety evaluation for the license amendment and exemption requests. The documents/calculations are listed in Section 3.1 of this audit plan.
3.1 List of Items for Audit Discussion and Review Westinghouse seismic analysis for mixed core (SNPB RAI-10/29/30).
Westinghouse large break and small break LOCA analyses (SNPB RAI-17/28).
During the site audit, the NRC staff reviewed APS calculation RA-13-C00-2019-016, Rev.00, Framatome VQP [Vendor Qualification Program]: Mixed Core Master Setpoint Overall Uncertainty Analysis Demonstration. The stated goal of this calculation is to show that the existing NRC-approved COLSS (core operating limits supervisory system) and CPC (core protection calculator) OUA (overall uncertainty analysis) methodology including the WCAP-16500, Supplement 1, Revision 1, eight-step process can be applied to both the next generation fuel and HTP' fuel types for the purpose of generating COLSS and CPC OUA Uncertainty Factors. As a result of the site audit, the setpoints process was further refined.
SNPB RAI-6 requested details on the augmented COLSS/CPCS [CPC system] MSCU [Modified Statistical Combination of Uncertainties] process and how this process was adjusted for CE16 HTP' fuel and mixed cores. The response to SNPB RAI-6 appears to be acceptable.
However, the staff would like to review the revision to APS calculation RA-13-C00-2019-016 to close the loop on this issue. In addition, the staff would like to discuss whether the revised setpoints process needs to be referenced in TS 5.6.5.
BHTP RAI-03 In its response, the licensee discussed the extended range, which was previously approved for LYNXT, but does not seem to compare to any of the data that was used in the previous validation.
BHTP RAI-05 The unit cell data looks to be in a non-conservative sub-region (i.e., if BHTP [designation for Framatome] correlation on unit cell data is used, 95/95 criteria will not be met). Also, the NRC staff needs clarification from the licensee whether APS checked the distribution shapes.
BHTP RAI-06 The NRC staff is not clear on how only looking at the points above the 95/95 limit will show non-conservative subregions.
SNPB RAI 19 The response omitted part of the requested information necessary for the NRC staff to complete its review. In particular, the NRC staff requested that the licensee estimate the observed change in peak cladding temperature (PCT) associated with an S-RELAP5 code modification autonomously implemented by Framatome following the NRC staffs review and approval of the small-break LOCA evaluation model described in EMF-2328(P)(A).
Both conservative requirements in Appendix K to 10 CFR Part 50 and guidance in Regulatory Guide 1.203, Transient and Accident Analysis Methods, December 2005 (ADAMS Accession No. ML053500170), reflect the importance of performing comparisons of evaluation model predictions against relevant test data. The assessment of the EMF-2328 evaluation model against test data, which constitutes part of the NRC staff's basis for finding the evaluation model acceptable, is specifically discussed in Section 4.5 of the NRC staffs safety evaluation on Revision 0 and Section 5.3 of the NRC staffs safety evaluation on Supplement 1. The validation of the evaluation model is further discussed in the submitted topical reports and a number of RAIs and responses concerning the EMF-2328 methodology.
Confirmation of the impact of the autonomously implemented code modification on the calculated PCT and other relevant figures of merit specified in 10 CFR 50.46(b) is necessary to confirm whether (1) the existing evaluation model assessment remains valid or (2) a new assessment is necessary with the modified evaluation model the licensee proposes to apply to Palo Verde.
SNPB RAI 22 The NRC staff requests that the licensee define the term zirconium-alloy clad. The RAI 22 response states that zirconium-alloy clad refers to cladding that has been approved by the NRC. This response does not appear sufficiently clear, since NRC approval of a fuel design does not appear to be directly related to whether the fuel is clad with a zirconium alloy.
In addition, the discussion concerning cladding coatings does not identify material properties or characteristics of the coating.
Paragraph 10 CFR 50.36(c)(4) states, in part, that Design features to be included [in the Design Features section of the technical specifications] are those features of the facility such as materials of construction and geometric arrangements, which, if altered or modified, would have a significant effect on safety and are not covered under 10 CFR 50.36(c)(1)-(3).
Because both the cladding base material and applied coatings may have a significant effect on safety, sufficient basis is not apparent for omitting the specific materials of construction from the technical specifications.
SNPB RAI 25 The licensee proposed no binding restriction to prohibit loading of mixed batches of fresh fuel. If the licensing basis changes in the requested amendment would allow for mixed fresh batch loading, it is not clear what is meant by the discussion in the RAI response that permission for mixed fresh batch loading is not being requested. The RAI response appears to constitute a regulatory commitment, which is not binding and cannot serve as the basis for a safety evaluation conclusion.
SNPB RAI 26 The licensees response states that The changes that Palo Verde proposed in this LAR are not related to the licensing of Westinghouse fuel. It is not clear that this statement accurately characterizes the impact of the proposed LAR on the licensing of Westinghouse fuel at Palo Verde. A number of proposed changes appear to apply to all fuel types that may be loaded at Palo Verde (i.e., including Westinghouse fuel designs), including the capability to begin using new fuels with different departure from nucleate boiling (DNB) correlations and cladding materials without prior NRC staff review. Therefore, the proposed changes would appear to eliminate significant opportunity for the NRC staff to request that the licensee update the existing license condition to address new Westinghouse fuel designs analyzed with the FATES3B code. Hence, it is not clear that (1) the licensees RAI response accurately depicts the impact of the proposed changes, and (2) the changes proposed by the licensee are capable of ensuring adequate treatment of future Westinghouse fuel designs loaded at Palo Verde with respect to thermal conductivity degradation.
SRXB RAI 3 As stated in response to SRXB RAI-3, APS is requesting NRC approval to use a time in DNB of less than 5 seconds as a criterion to ensure that DNB propagation of Framatome fuel with M5 cladding will not occur. The NRC staff would like to discuss the range of applicability of the M5 time-in-DNB criterion. The legacy ABB [Westinghouse]-CE calculation A-GM-FE-0048, Rev.04, Parametric Analysis of DNB Propagation in ABB-CE 16x16 Fuel, provides the bases for the existing time-in-DNB criteria (used for Westinghouse fuel). Within that calculation, there is a range of applicability defined for the following parameters:
Rod internal pressure Reactor coolant system pressure Coolant quality Coolant mass flux Cladding heat flux
APS credits creep testing performed at the EDGAR facility for the technical bases supporting the time-in-DNB criterion. After reading the cited reference, it is not clear whether the test chamber was at pressurized-water reactor pressure or atmospheric pressure. The NRC staff would like to understand the range of applicability of these tests and how this range will be assessed against predicted local conditions for the various postulated accidents, which rely on this criterion. For example, ballooning dynamics change dramatically with temperature. It is not clear that 600 °centigrade bounds expected cladding temperatures during postulated accidents.
Further discussion is necessary to assess whether the plant-specific conditions at Palo Verde are bounded by the full set of assumptions associated with the proposed 5-second time limit in DNB.
3.2 Supporting Information from the Licensee The licensee is requested to make the appropriate personnel or contractors who are familiar with the proposed LAR available for the audits (either in person or on the phone). The NRC staff also requests the licensee to have the supporting documents related to the above topics available and be prepared to discuss them with the staff during the audit. The documents could be provided by paper copies or electronically. The NRC staff may require the licensee to provide appropriate documents on the NRC docket that would enable an accelerated and effective review of the LAR.
4.0 TEAM AND REVIEW ASSIGNMENTS Area of Review Assigned Auditor Branch Chief Jennifer Dixon-Herrity (NRC/NRR)
Branch Chief Robert Lukes (NRC/NRR)
Branch Chief (A)
Joshua Borromeo (NRC/NRR)
Technical Adviser Paul Clifford (NRC/NRR)
Technical Reviewer Ravi Grover (NRC/NRR)
Technical Reviewer Joshua Kaizer (NRC/NRR)
Technical Reviewer John Lehning (NRC/NRR)
Technical Reviewer Mathew Panicker (NRC/NRR)
Technical Reviewer Diana Woodyatt (NRC/NRR)
Project Manager Siva Lingam (NRC/NRR) 5.0 LOGISTICS The audit will be conducted at the Westinghouse facility in Bethesda, Maryland, on November 7, 2019, starting at 8:00 a.m. Eastern time and ending at 4:30 p.m., and in Marriott Hotel on November 8, 2019, starting at 8:00 a.m. and ending at 2:00 p.m. Eastern time.
Entrance and exit briefings will be held at the beginning and end of this audit, respectively.
The licensee is requested to provide a conference room with a white board for discussions.
The licensee should also provide any other documentation that may aid discussion on the specific topics of interest.
The audit will start at 8:00 a.m. on Thursday, November 7, 2019, and conclude on Friday, November 8, 2019, at 2:00 p.m. approximately (subject to change).
Please note the following proposed schedule that is also subject to change:
November 7, 2019 (at Westinghouse Facility) 8:00 a.m.
Entrance Meeting - Introductions, Audit Activities, Goals, and Logistics 8:15 a.m.
Licensee and NRC Staff to Review Westinghouse Seismic and LOCA analyses (RAIs SNPB RAI-10/17/28/29/30) 12:00 p.m.
Lunch 1:00 p.m.
Continue the Review 4:15 p.m.
Discuss the Audit Results 4:30 p.m.
Exit November 8, 2019 (at Marriott Hotel) 8:00 a.m.
Discuss the remaining RAIs Listed in Sections 2.0 and 3.1 of this Audit Plan 12:00 p.m.
Lunch 12:30 p.m.
Continue the Discussion of the RAIs 1:30 p.m.
Discuss the Audit Results 2:00 p.m.
Audit Exit 6.0 DELIVERABLES At the conclusion of the audit, the NRC staff will provide a summary of audit results for each of the topics defined in the audit scope. Further, as a result of this audit, the staff will identify any open items. The staff will also document its understanding of the proposed resolution of any identified open items. The audit report will be provided to the licensee in draft form for proprietary markup. Additionally, the results of the audit will be utilized to focus the scope of any RAIs issued in the course of this review. The NRCs final Regulatory Audit Report will be issued within 90 days of the completion of the audit.