ML19234A320
| ML19234A320 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 08/29/2019 |
| 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: ML19234A320 (32) | |
Text
OFFICIAL USE ONLY PROPRIETARY INFORMATION UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 August 29, 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-REQUEST FOR ADDITIONAL INFORMATION FOR AMENDMENT AND EXEMPTION REQUEST ASSOCIATED WITH REVISING TECHNICAL SPECIFICATIONS TO SUPPORT THE IMPLEMENTATION OF FRAMATOME HIGH THERMAL PERFORMANCE FUEL (EPID L-2018-LLA-0194; EPID L-2018-LLE-0010)
Dear Mr. Bement:
By application dated July 6, 2018, as supplemented by letters dated October 18, 2018, March 1, 2019, and May 17, 2019, Arizona Public Service Company (APS, the licensee) submitted a license amendment and exemption request for Palo Verde Nuclear Generating Station (Palo Verde), Units 1, 2, and 3. The proposed amendments and exemptions would support the implementation of Framatome High Thermal Performance {HTP') fuel. By letter dated October 18, 2018, the licensee provided supplemental information to support the U.S. Nuclear Regulatory Commission (NRC) acceptance of the requests.
The proposed amendments would revise the Palo Verde Technical Specifications (TSs) to support the implementation of Framatome Advanced Combustion Engineering (CE) 16x16 (CE-16) HTP' fuel design with MS as a fuel rod cladding material and gadolinia as a burnable absorber. In addition to the license amendment, pursuant to Title 10 of the Code of Federal Regulations (10 CFR) Section 50.12, "Specific exemptions," APS is requesting an exemption from the requirements of 10 CFR 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 the Framatome MS alloy as a fuel rod cladding material. In addition, the proposed amendments 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)." to this letter contains Proprietary information. When separated from Enclosure 1, this document is DECONTROLLED.
OFFICIAL USE ONLY PROPRIETARY INFORMATION
R. Bement OFFICIAL USE ONLY PROPRIETARY INFORMATION This license amendment request seeks approval of a reload analysis methodology that addresses both Westinghouse and Framatome fuel, including the implementation of selected Framatome methodologies, parameters, and correlations. According to the licensee, 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 has completed the review of the license amendment request, the supplemental information, and the materials discussed in the audits. The staff requires additional information to complete its review of this request as detailed in the enclosures to this letter. Please provide your responses within 30 days from the date of this letter as mutually agreed during the clarification call held on August 15 and August 21, 2019.
If you have any questions, please contact me at 301-415-1564 or via e-mail at Siva.Linqam@nrc.gov.
Docket Nos. STN 50-528, STN 50-529, and STN 50-530
Enclosures:
Sincerely,
/RA/
Siva P. Lingam, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
- 1. Request for Additional Information (Proprietary)
- 2. Request for Additional Information (Non-Proprietary) cc w/o Enclosure 1: Listserv OFFICIAL USE ONLY PROPRIETARY INFORMATION
ENCLOSURE 2 REQUEST FOR ADDITIONAL INFORMATION RELATED TO FRAMATOME HTP' FUEL LICENSE AMENDMENT AND EXEMPTION REQUEST FOR 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 (NON-PROPRIETARY)
Proprietary information pursuant to Section 2.390 of Title 10 of the Code of Federal Regulations has been redacted from this document.
Redacted information is identified by blank space enc_losed with double brackets.
OFFICIAL USE ONLY PROPRIETARY INFORMATION REQUEST FOR ADDITIONAL INFORMATION FOR LICENSE AMENDMENT AND EXEMPTION REQUEST REGARDING IMPLEMENTATION OF FRAMATOME HIGH THERMAL PERFORMANCE FUEL ARIZONA PUBLIC SERVICE COMPANY PALO VERDE NUCLEAR GENERATING STATION, UNITS 1, 2, AND 3 DOCKET NOS. 50-528, 50-529, AND 50-530 By application 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, and May 17, 2019 (ADAMS Accession Nos. ML18296A466, ML19060A298, and ML19137A118, respectively), Arizona Public Service Company (APS, the licensee) submitted a license amendment and exemption request for Palo Verde Nuclear Generating Station, Units 1, 2, and 3 (Palo Verde or PVNGS). The proposed amendments and exemptions would support the implementation of Framatome High Thermal Performance (HTP') Fuel. By letter dated October 18, 2018, the licensee provided supplemental information to support the U.S. Nuclear Regulatory Commission (NRC) acceptance of the requests.
The proposed amendments would revise the Palo Verde Technical Specifications (TSs) to support the implementation of Framatome Advanced Combustion Engineering (CE) 16x16 (CE-16) HTP' fuel design with M5 as a fuel rod cladding material and gadolinia as a burnable absorber. In addition to the license amendment request (LAR), pursuant to Title 10 of the Code of Federal Regulations (10 CFR) Section 50.12, "Specific exemptions," APS is requesting an exemption from the requirements of 10 CFR 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 the Framatome M5 alloy as a fuel rod cladding material. In addition, 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 LAR seeks approval of a reload analysis methodology that addresses both Westinghouse Electric Company (Westinghouse) and Framatome fuel, including the implementation of selected Framatome methodologies, parameters, and correlations. According to the licensee, 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 has partially completed the review of the LAR, the supplemental information, and the materials discussed in the audits. The staff requires additional information to complete its review of this request as detailed below.
For some requests for additional information (RAls), the NRC staff has used an RAI categorization process that is given in "DSS [Division of Safety Systems] Open Item Categorization Process" dated February 15, 2018 (ADAMS Accession No. ML18017A064).
OFFICIAL USE ONLY PROPRIETARY INFORMATION
OFFICIAL USE ONLY PROPRIETARY INFORMATION Proprietary information contained in this document is enclosed between bolded double square brackets, ((.... )).
Regulatory Information The review of the Palo Verde LAR for Framatome fuel transition is mainly based on the following NRC guidance, as well as appropriate sections of the General Design Criteria (GDC) listed in Appendix A, "General Design Criteria for Nuclear Power Plants," to 10 CFR Part 50:
NUREG-0800, "Standard Review Plan [SRP] for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR [Light-Water Reactor] Edition" (hereafter, referred to as the SRP), including:
o Chapter 4, Section 4.2, "Fuel System Design," Revision 3, dated March 2007 (ADAMS Accession No. ML070740002);
o Chapter 4, Section 4.3, "Nuclear Design," Revision 3, dated March 2007 (ADAMS Accession No. ML070740003);
o Chapter 4, Section 4.4, 'Thermal and Hydraulic Design," Revision 2, dated March 2007 (ADAMS Accession No. ML070550060); and o
Chapter 15, "Transient and Accident Analysis" Regulatory Guide (RG) 1.203, "Transients and Accident Analysis Methods," dated December 2005 (ADAMS Accession No. ML053500170).
The following applicable sections of the GDC of Appendix A to 10 CFR Part 50:
o Criterion 10, "Reactor design";
o Criterion 11, "Reactor inherent protection";
o Criterion 15, "Reactor coolant system design";
o Criterion 20, "Protection system functions";
o Criterion 24, "Separation of protection and control systems";
o Criterion 26, "Reactivity control system redundancy and capability"; and o
Criterion 35, Emergency core cooling."
SNPB RAl-1 TS 5.6.5.b states that "The analytical limits used to determine the core operating limits shall be those previously reviewed and approved by NRC." In the Enclosure, "Description and Assessment of Proposed License Amendment," of the LAR dated July 6, 2018, the licensee stated, in part:
This LAR will adapt the approved PVNGS 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 PVNGS fuel OFFICIAL USE ONLY PROPRIETARY INFORMATION
OFFICIAL USE ONLY PROPRIETARY INFORMATION supply by providing for multiple fuel vendors with reliable fuel designs and geographically diverse manufacturing facilities.
- a.
The licensee states that "... the approved PVNGS reload analysis methodology to address both Westinghouse and Framatome fuel, including the implementation of Framatome methodologies.... " This statement implies that there is an approved Palo Verde methodology for Framatome fuel designs. The NRC staff is not aware of an approved Palo Verde methodology for Framatome fuel designs. Please clarify this statement to remove the ambiguity with respect to approved methodology for Framatome fuel designs.
- b.
Please elaborate on your plan to use both Framatome and Westinghouse fuel designs and their respective methodologies in the Palo Verde units.
SNPB RAl-2 Criterion 10 of Appendix A to 10 CFR Part 50 requires "that specified acceptable fuel design limits [SAFDLs] are not exceeded during any condition of normal operation, including the effects of anticipated operational occurrences."
Section 4 of Attachment 5, "Assessment of Topical Report Limitations and Conditions," of the LAR dated July 6, 2018, briefly discusses the BHTP (designation for a Framatome Critical Heat Flux (CHF) Correlation) correlation verification for VIPRE-01 (Versatile Internals and Component Program for Reactors; Electric Power Research Institute (EPRI)) and VIPRE-W (Versatile Internals and Component Program for Reactors; Westinghouse) codes based on the same CHF test points used in the development of HTP' CHF correlation for use with the thermal-hydraulic subchannel code XCOBRA-IIIC.
- a.
Provide details on how a CHF design limit was determined from the CHF test points.
- b.
Provide details on how the statistical design limit for departure from nucleate boiling ratio (DNBR) was calculated as per Section 4.2 of Attachment 5 and Section 5.4.1 of 0.
SNPB RAl-3 The regulatory basis for this RAI includes Criterion 20, Criterion 24 and Criterion 26 of Appendix A to 10 CFR Part 50.
CEN-356(V)-P-A, Revision 01-P-A, "Modified Statistical Combination of Uncertainties," dated May 1988 and WCAP-16500-P-A, Supplement 1, Revision 1, "Application of CE Setpoint Methodology for CE 16x16 Next Generation Fuel (NGF)," dated December 2010 are NRC-approved methodologies for core operating limits supervisor system (COLSS) and core protection calculator system (CPCS) setpoints analysis specifically for CE type fuel designs.
- a.
Please explain how the above methodologies are used for COLSS/CPCS analysis with the Framatome CE 16x16 fuel in the Palo Verde core.
- b.
Explain the modifications that had to be made to the above methodologies in order to analyze the digital COLSS/CPCS setpoints for the mixed core (three different fuel types; OFFICIAL USE ONLY PROPRIETARY INFORMATION
OFFICIAL USE ONLY PROPRIETARY INFORMATION CE 16x16 STD (standard or value-added), CE 16x16 NGF and CE 16x16 HTP') in the Palo Verde core.
SNPB RAl-4 The regulatory basis for this RAI is Criterion 20, Criterion 24 and Criterion 26 of Appendix A to 10 CFR Part 50.
In the supplemental letter dated October 18, 2018, the licensee indicated that the COLSS/CPCS setpoint analysis performs two major functions: (1) ((
)) for the reload cycle, and (2) perform the COLSS/CPCS overall uncertainty analysis (QUA) to provide the final overall COLSS and CPCS uncertainty factors to ensure that COLSS/CPCS DNBR and linear heat rate/linear power density calculations are conservative with a 95 percent probability and a 95 percent confidence level.
- a.
Describe in detail how the COLSS and CPCS QUA are determined for the mixed core in the Palo Verde core.
- b.
Describe the process in which the COLSS/CPCS database constants are determined.
- c.
Provide a summary of the thermal margin assessment performed as part of the COLSS/CPCS analysis for the Palo Verde mixed core.
SNPB RAl-5 The regulatory basis for this RAI is Criterion 20, Criterion 24 and Criterion 26 of Appendix A to 10 CFR Part 50.
In the supplemental letter dated October 18, 2018, the licensee stated that the fuel dependent factors such as rod bow factors, core neutronics design, thermal-hydraulics design, and fuel performance analyses are updated to reflect fuel type prior to use in the COLSS/CPCS QUA.
Explain in detail how the above update process is performed and implemented to generate the setpoints.
SNPB RAl-6 The regulatory basis for this RAI is Criterion 10 of Appendix A to 1 O CFR Part 50.
In response to NRC Question 7, in the licensee's supplemental letter dated October 18, 2018, points to an "augmented process" for the mixed core with Westinghouse NGF and Framatome fuel. During the last regulatory audit, the licensee stated that this "augmented process" is described in the NRC-approved topical report WCAP-16500, Supplement 1, Revision 1.
However, the "eight steps" process described in the topical report appears to be for the Westinghouse NGF fuel design. Justify the use of this "augmented process" for the Palo Verde core with both NGF and Framatome fuel designs.
OFFICIAL USE ONLY PROPRIETARY INFORMATION
SNPB RAl-7 OFFICIAL USE ONLY PROPRIETARY INFORMATION The regulatory basis for this RAI is Criterion 10 of Appendix A to 10 CFR Part 50.
For mixed cores with Framatome fuel,
- a.
Explain how the potentially limiting fuel type is identified.
- b.
Describe how the fuel-specific CETOP (Combustion Engineering Thermal On-Line Program) correction factors are determined for the setpoints analysis.
SNPB RAl-8 The regulatory basis for this RAI is Criterion 10 of Appendix A to 10 CFR Part 50.
Explain the procedures and results from the mechanical compatibility analysis of Framatome fuel with the resident CE STD and CE NGF fuel design, as well as all of the core internals.
SNPB RAl-9 The regulatory basis for this RAI is RG 1.203 and Criterion 10 of Appendix A to 10 CFR Part 50.
Provide details of the following analyses that are summarized in the licensee's supplemental letter dated October 18, 2018 (Response to NRC Question 3):
- a.
Mixed core compatibility evaluations.
- b.
CE 16 HTP' Thermal-hydraulic Characterization.
- c.
Mixed core thermal margin performance specifically explains how the ((
)).
- d.
Explain the ((
)).
SNPB RAl-10 The regulatory basis for this RAI is Appendix S, "Earthquake Engineering Criteria for Nuclear Power Plants," to 10 CFR Part 50 and 10 CFR 50.46.
ANP-10337P-A, "PWR [Pressurized-Water Reactor] is an NRC-approved methodology for a faulted condition (earthquakes and postulated pipe breaks in the reactor coolant system) analysis for cores containing Framatome fuel designs. However, the Palo Verde core will have three different fuel designs, including CE STD and CE NGF designs. Explain how the faulted condition analysis will be performed for Palo Verde mixed core conditions.
SNPB RAl-11 The regulatory basis for this RAI is 10 CFR 50.46(b)(5), "Long term cooling," that states, "After any calculated successful initial operation of the ECCS, the calculated core temperature shall be OFFICIAL USE ONLY PROPRIETARY INFORMATION
OFFICIAL USE ONLY PROPRIETARY INFORMATION maintained at an acceptably low value and decay heat shall be removed for the extended period of time required by the long-lived radioactivity remaining in the core."
Please clarify the performance of the Framatome HTP' fuel design relative to the fuel currently loaded at Palo Verde with respect to the concerns identified in Generic Letter (GL) 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors," associated with debris blockage following a loss-of-coolant accident (LOCA). The NRC staff seeks to assure that plant modifications during the interim period prior to the plant-specific resolution of all concerns identified in GL 2004-02 adequately consider impacts of post-LOCA debris blockage to avoid unwarranted increases in the potential for inadequate long-term core cooling. Hence, this information request is necessary to assure that the proposed transition to HTP' fuel adequately accounts for 10 CFR 50.46(b )(5) requirements pending the plant-specific resolution of GL 2004-02 concerns.
SNPB RAl-12 The NRC staff's review of the calculated results in ANP-3639P, "Palo Verde Units 1, 2, and 3 Realistic Large Break LOCA Summary Report," identified certain datapoints that appear to be outliers with respect to the main body of data. Information available in the submittal does not provide a reasonable physical explanation for the predicted behavior in these outlying cases.
To provide reasonable assurance that implementation of the Realistic Large-Break LOCA methodology at Palo Verde produces expected results when computing the figures of merit required for comparison against the acceptance criteria in 10 CFR 50.46(b ), please
- a.
Provide a physical explanation for the following outlying predictions:
Figure 3-2, "PCT [Peak Cladding Temperature] versus PCT Time Scatter Plot," of ANP-3639 shows that the case that sets the statistical limit for PCT is ((
)).
Figure 3-4, "Maximum Local Oxidation versus PCT Scatter Plot," of ANP-3639 shows that ((
))
- b.
Provide the maximum local oxidation for each case shown in Table A-1, "Summary of Key Input and Output Parameters, Part 1," of ANP-3639P.
SNPB RAl-13 Section 4.3 of ANP-3640P, "Palo Verde Units 1, 2, and 3 Small Break LOCA [SBLOCA]
Summary Report," describes delayed reactor coolant pump trip sensitivity studies. To ensure that these sensitivity studies are sufficient to provide confidence that the most severe postulated conditions consistent with 10 CFR 50.46 have been calculated, please provide the following information:
OFFICIAL USE ONLY PROPRIETARY INFORMATION
OFFICIAL USE ONLY PROPRIETARY INFORMATION a.
The results of the break sizes that were analyzed for the hot leg and cold leg sensitivity studies in tables similar to those provided in Table 4-1, "Summary of SBLOCA Break Spectrum Transient Results," of ANP-3640P.
- b.
The results for the limiting break sizes for the cold leg and hot leg cases in a table similar to those provided in Table 4-2, "Sequence of Events for Break Spectrum (seconds)," of ANP-3640P.
- c.
Discuss the modeling used for loop seal biasing in the hot leg and cold leg sensitivity,
studies and discuss if it was necessary to ((
)) for the studies.
SNPB RAl-14 To assure the conservatism of the SBLOCA analysis used to demonstrate compliance with the limits of 10 CFR 50.46(b ), please provide justification that the 5-minute reactor coolant pump trip delay time assumed in ANP-3640P considers the limiting condition with respect to reactor coolant pump operation for the full range of postulated small breaks on both the cold and hot legs. Please address in particular the range of larger breaks in the SBLOCA spectrum. For such breaks, a 5-minute delay time is essentially equivalent to running the reactor coolant pumps throughout the event, which has long been known to result in reduced PCTs. In responding, please identify the most likely range of times over which plant operators will manually trip the reactor coolant pumps and explain why there is confidence that a reactor coolant pump trip in this time range would be bounded by the existing analyses.
Alternatively, please perform additional sensitivity studies that consider reduced reactor coolant pump trip time delays for break sizes 5 inches and larger to ensure satisfaction of the requirement in 10 CFR 50.46(a)(1 )(i) that there is assurance that the most severe postulated LOCAs are calculated. Please further provide a basis for considering any revised sensitivity studies as covering the potential range of times when operators would be expected to complete actions to manually trip the reactor coolant pumps.
SNPB RAl-15
((
))
((
))
OFFICIAL USE ONLY PROPRIETARY INFORMATION
OFFICIAL USE ONLY PROPRIETARY INFORMATION SNPB RAl-16 The NRC staff's safety evaluation for EMF-2328(P)(A), Revision 0, Supplement 1, states that
((
)) ANP-3640P does not discuss whether switchover to the containment recirculation sump could occur prior to core quench for some SBLOCA events, or whether this behavior was explicitly modeled. Therefore, to ensure a conservative calculation of the figures of merit required to satisfy the acceptance criteria in 10 CFR 50.46(b ),
- a.
Please identify whether the switchover to sump recirculation could occur prior to core quench for the spectrum of break sizes considered in ANP-3640P. If switchover prior to core quench is not possible, please provide justification.
- b.
If switchover to sump recirculation could occur prior to core quench for breaks in the size range considered in ANP-3640P, then please either (1) demonstrate that the reported figures of merit remain adequately conservative or (2) reanalyze the affected cases with an explicit modeling of sump recirculation.
SNPB RAl-17 Realistic, with allowance for uncertainty, or conservative modeling of the fuel in the reactor core is necessary to ensure that appropriately conservative figures of merit are predicted for comparison against the acceptance criteria in 10 CFR 50.46(b ). Please justify how both the Framatome and Westinghouse LOCA analyses for Palo Verde would address the potential suite of mixed core configurations that could ensue following implementation of the proposed license amendment.
- a.
Please describe whether and how each vendor's existing LOCA analysis for both small and large breaks consider a bounding core configuration that would address the impacts of potential variations in core composition on the predicted LOCA figures of merit.
- b.
Please clarify and justify the conditions under which each analysis would be deemed applicable to a given mixed core configuration, and the conditions under which an explicit analysis of a particular mixed core configuration would become necessary.
SNPB RAl-18 Several figures included in ANP-3640P that plot key parameters predicted for the limiting SBLOCA event display behavior that may appear non-physical. To assure that the predicted figures of merit for this event are calculated correctly such that reasonable assurance exists that the acceptance criteria in 10 CFR 50.46(b) have been satisfied, please provide justification that the following calculated behavior is reasonable:
- a.
Prior to 200 seconds into the event, the steam generator total mass in Figure 4-14, "Steam Generator Total Mass - 9.10 Inch Break," of ANP-3640P begins to vary as a OFFICIAL USE ONLY PROPRIETARY INFORMATION
OFFICIAL USE ONLY PROPRIETARY INFORMATION function of time, despite Figures 4-11 (main feedwater flow), 4-12 (steam generator safety valve mass flow) and 4-13 (auxiliary feedwater flow) showing no appreciable changes in the mass flow into or out of the steam generators.
- b.
After about 200 seconds into the event, the hot assembly mixture level in Figure 4-22, "Hot Assembly Mixture Level - 9.10 inch Break," of ANP-3640P appears to take several different, approximately constant, values across several different periods, most prominently between approximately 355 and 620 seconds; whereas it is not obvious why the hot assembly mixture level should remain approximately constant during this period at a number of distinct values, all of which are below the top of active fuel.
SNPB RAl-19 As discussed in the LAR, the SBLOCA analysis methods proposed for Palo Verde include a deviation from the approved EMF-2328(P)(A) methodology. ((
11 To ensure that the methodology continues to appropriately predict a SBLOCA transient for demonstrating compliance with 10 CFR 50.46(b) acceptance criteria, please address the following:
- a.
((
11
- b.
((
11 C.
((
))
- d.
((
. 11 SNPB RAl-20 Please clarify and justify the modeling of non-Framatome fuel in the large-break LOCA analysis in ANP-3639P.
In particular, ANP-3639P states that In addition to the Framatome HTP' fuel, the hydraulic Gharacteristics of other fuel types that could be present in the core were considered. ((
11 OFFICIAL USE ONLY PROPRIETARY INFORMATION
OFFICIAL USE ONLY PROPRIETARY INFORMATION However, Limitation 4.3 associated with EMF-2103P-A states that the methodology is applicable to fuel with M5 cladding, and that application of the evaluation model to fuel with other types of cladding has not been reviewed. Furthermore, it is not clear how the fuel pellet and cladding thermal-mechanical behavior is modeled for non-Framatome fuel (1) as a function of burnup to support initialization of the LOCA calculation and (2) during the LOCA transient calculation.
Clarification and justification regarding the modeling of non-Framatome fuel in the large-break LOCA analysis is necessary to ensure that figures of merit are calculated in a representative or conservative manner in order to satisfy the acceptance criteria in 10 CFR 50.46(b) during operating cycles with multiple fuel types present in the reactor core.
SNPB RAl-21 Proposed TS SL 2.1.1.2 would specify separate fuel centerline melt limits for "Westinghouse supplied fuel" and "Framatome supplied fuel." However, it is not clear that the proposed terminology is sufficiently precise, since certain types of fuel supplied by Westinghouse or Framatome may be incompatible with the proposed limits. To assure satisfaction of 10 CFR 50.36( c )( 1 ), please clarify whether additional description is necessary in proposed TS SL 2.1.1.2 (e.g., fuel design, applicable topical report methodology) to avoid unsupportable broad interpretations of the proposed wording:
- a.
Regarding proposed TS SL 2.1.1.2.1, please clarify any applicability criteria (e.g., burnable absorber material) that must be satisfied to apply the fuel centerline melt methodology specified in CENPD-382-P-A to Westinghouse-supplied fuel.
- b.
Regarding proposed TS SL 2.1.1.2.2, please identify any applicability criteria that must be satisfied to apply the proposed fuel centerline melt limit to Framatome-supplied fuel.
Please further identify whether the wording of proposed TS SL 2.1.1.2.2 should be modified to reflect the source of the methodology, such that the limits of applicability are unequivocally defined within the safety limit.
SNPB RAl-22 The description of fuel assemblies contained in proposed TS 4.2.1 would replace the names of three specific types of cladding that have been approved for use at Palo Verde with the term "zirconium-alloy clad." The term "zirconium-alloy clad" in proposed TS 4.2.1 has not been defined, and its intent is not clear with respect to either conventional or coated cladding types.
As such, it is not clear that replacement of specific cladding alloys with an undefined generic term would create an enforceable TS requirement capable of satisfying regulatory requirements in 1 O CFR 50.36, "Technical specifications."
- a.
Please clarify the intended definition of the term "zirconium-alloy clad" and discuss how the wording of the proposed TS and its basis would assure an unambiguous interpretation that satisfies applicable regulatory requirements. In particular, the requested information is necessary to confirm satisfaction of 10 CFR 50.36(c)(4), which 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 OFFICIAL USE ONLY PROPRIETARY INFORMATION
OFFICIAL USE ONLY PROPRIETARY INFORMATION 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).
- b.
Marked up TS page 4.0-1 in Attachment 2 of the LAR dated July 6, 2018, does not highlight addition of the term "zirconium-alloy clad" as a proposed change to TS 4.2.1.
Please clarify whether this is an omission, and, as necessary, provide a corrected markup of page 4.0-1.
SNPB RAl-23 Please clarify the intended meaning of proposed TS 4.2.1 with respect to the materials allowed for lead test assemblies and discuss whether the intended meaning is consistent with a plain-language, literal interpretation. In particular, proposed TS 4.2.1 states that The reactor shall contain 241 fuel assemblies. Each assembly shall consist of a matrix of zirconium-alloy clad fuel rods with an initial composition of natural or slightly enriched uranium dioxide (U02) as fuel material.
The proposed change to TS 4.2.1 would further delete an exception to allow lead test assemblies to use cladding types other than those described in TS 4.2.1. Consequently, it appears that proposed TS 4.2.1 would require lead test assemblies (i.e., which number among the 241 fuel assemblies in the reactor) to have the properties described in the passage quoted above. Clarification of proposed TS 4.2.1 is necessary for the NRC staff to confirm that reactor design features have been adequately specified in TSs, in satisfaction of 10 CFR 50.36(c)(4).
SNPB RAl-24 The proposed license amendments would add a suite of Framatome methodologies to Palo Verde TS 5.6.5 (Core Operating Limits Report), without deleting corresponding Westinghouse methodologies. To assure that the administrative controls in proposed Palo Verde TS 5.6.5 are sufficient to support operation of the facility in a safe manner in accordance with 10 CFR 50.36(c)(5), please provide the following information:
- a.
For each analytical methodology in TS 5.6.5, please identify whether the methodology is restricted in its application to fuel assemblies supplied by a particular vendor, or whether it would be applicable to both Framatome and Westinghouse fuel designs.
- b.
Please identify and provide justification for any instances where topical report methodologies supplied by one fuel vendor would be used to generate core operating limits for fuel supplied by a different vendor.
SNPB RAl-25 Historically, the analytical methods of domestic fuel vendors have generally been developed for application to reactor cores where all fresh fuel assemblies have been manufactured by that same vendor. In light of U.S. nuclear plants' historical reliance upon a single fuel supplier for one or typically a number of fuel cycles, however, such a restriction may not be specified explicitly in each topical report (or its corresponding safety evaluation) in proposed Palo Verde TS 5.6.5. To assure that the administrative controls in proposed Palo Verde TS 5.6.5 are OFFICIAL USE ONLY PROPRIETARY INFORMATION
OFFICIAL USE ONLY PROPRIETARY INFORMATION sufficient to assure operation of the facility in a safe manner, in accordance with 10 CFR 50.36(c)(5),
- a.
Please clarify whether implementation of the proposed LAR would permit operation with mixed batches of fresh fuel in the reactor core of any unit at Palo Verde.
- b.
If implementation of the proposed license amendment would permit operation with mixed batches of fresh fuel under existing regulatory requirements applicable to Palo Verde, then please either
- i.
provide justification for the acceptability of using mixed batches of fresh fuel, considering the applicability of the full suite of reload analysis and COLR methodologies, including the potential for increased uncertainties associated with mixed batches of fresh fuel and any validation of the analytical methods for such conditions, or ii.
propose a binding restriction that would forbid operation with mixed batches of fresh fuel.
- c.
If, following implementation of the proposed license amendments, operation with mixed batches of fresh fuel would not be permitted under existing regulatory requirements applicable to Palo Verde, then please identify the specific requirement(s) that would preclude operation with mixed batches of fresh fuel.
SNPB RAl-26 The proposed LAR would implement changes that may obviate future NRC review of certain types of fuel transitions that have historically been subject to review. As such, please justify whether a revision is necessary to the license condition imposed in Amendment No. 205 (which applies a restriction specific to Westinghouse NGF) to ensure its compatibility with the proposed license amendments. In particular, to assure compliance with the acceptance criteria in 10 CFR 50.46(b ), as well other regulatory requirements for fuel integrity deriving from GDC 10, please clarify whether the terms of the license condition should apply, not only to NGF, but to any future Westinghouse-supplied fuel designs introduced at Palo Verde to which FATES3B would be applied.
SNPB RAl-27 In order for the NRC staff to confirm the licensee's determination that the existing evaluation of long-term core cooling remains applicable to Palo Verde and continues to satisfy 10 CFR 50.46(b)(5), please either (1) confirm that the values in Tables 8-13 and 8-15 of to the LAR dated July 6, 2018, to implement Westinghouse NGF dated July 1, 2016, remain valid, or (2) identify any changes and justify that the revised values do not adversely affect the calculated results.
SNPB RAl-28 In order to confirm that introduction of Framatome HTP' fuel will support continued compliance with the acceptance criteria in 10 CFR 50.46(b) for other types of co-resident fuel, please OFFICIAL USE ONLY PROPRIETARY INFORMATION
OFFICIAL USE ONLY PROPRIETARY INFORMATION a.
describe the Westinghouse large-and small-break LOCA analyses performed for mixed core conditions involving Framatome HTP' fuel,
- b.
provide the results of these Westinghouse large-and small-break LOCA analyses and confirm that the acceptance criteria of 10 CFR 50.46(b) remain satisfied.
SNPB RAl-29 Section 2.3.2 of Attachment 10 of the LAR dated July 6, 2018, describes the fuel assembly structural analyses, including externally applied forces such as earthquakes and postulated pipe breaks. The analyses supporting the Advanced CE16 HTP' fuel assembly and the use of the approved Framatome methodology in ANP-10337P-A is described. However, there is little discussion on the impact of a mixed core containing CE16STD, CE16NGF, and CE16 HTP' fuel bundles on the predicted response of each fuel assembly design (i.e., margin to respective design criteria).
- a.
Discuss the sensitivity studies conducted to identify the limiting mixed core configurations with respect to each fuel assembly design, predicted results (i.e., margin to respective design criteria), and how future core loading patterns will demonstrate that these calculations remain bounding.
- b.
Each fuel vendor has separately analyzed mixed core configurations and the performance of their respective fuel assemblies. Provide a comparison of Westinghouse and Framatome dynamic model predictions (e.g. horizontal accelerations, impact loads) and identify and disposition inconsistencies.
- c.
Discuss the methods used to assess differences in spacer grid (and mid-grid mixing grids) axial location and height.
SNPB RAl-30 Section 2.4, "End-of-Life Grid Crush Strength for CE16HTP Fuel," of Attachment 10 of the LAR dated July 6, 2018, describes the Framatome methodology in ANP-10337P-A and how irradiation effects, identified in Information Notice (IN) 2012-09, "Irradiation Effects on Fuel Assembly Spacer Grid Crush Strength," have. been addressed for CE16 HTP' fuel assemblies.
- a.
Describe how irradiation effects (e.g., grid crush strength, grid stiffness, bundle stiffness) are addressed iri the mixed core configuration.
- b.
Considering this new, and potentially more limiting mixed core utilization of the CE16STD and CE16NGF fuel assemblies, describe the level of confidence in the predicted seismic/LOCA performance using the Westinghouse methodology, which does not address the irradiation effects identified in IN 2012-09.
- i.
Provide predicted margin relative to each CE16STD and CE16NGF design criteria.
OFFICIAL USE ONLY PROPRIETARY INFORMATION
OFFICIAL USE ONLY PROPRIETARY INFORMATION SRXB RAl-1 The regulatory basis for this RAI is 10 CFR 50.36 and Criterion 10 of Appendix A to 10 CFR Part 50.
For multiple non-LOCA transients, the LAR dated July 6, 2018, states that "The transient Linear Heat Rate (LHR) will not exceed 21.0kW/ft [kilowatt per foot]. Therefore, the fuel centerline melt temperature will not be exceeded."
However, Table 2-3, "CFM Rod Local LHGR Limits," of Attachment 10, of the LAR indicates that 21.0kW/ft will not preclude centerline melt for ((
)). Provide additional information to demonstrate that fuel centerline melt temperature will not be exceeded for Updated Final Safety Analysis Report (UFSAR) events 15.1.3, 15.1.4, 15.1.5, 15.1.6, and 15.2.3.
SRXB RAl-2 The regulatory basis for this RAI is 10 CFR 50.36 and Criterion 10 of Appendix A to 10 CFR Part 50.
For multiple transients, the LAR dated July 6, 2018, states that "The maximum LHGR [linear heat generation rate] will remain below the value that causes peak centerline melt temperature (TS 2.1.1.2 limit)."
However, the TS 2.1.1.2 limit is provided in terms of peak fuel centerline temperature. Further, there are separate limits for Westinghouse Supplied Fuel and for Framatome Supplied Fuel, which vary as a function of burnup as plotted below.
TS SL 2.1.1.2 5150 E 5100
~
.a 5050
~
-- Westinghouse supplied fuel QJ
- a. 5000 E
-- Framatome supplied fuel i!!! -
4950 cii
~ 4900 QJ C
~ 4850 c
QJ 4800 u
cii 4750 u..
ro 4700 QJ Cl.
4650 0
20 40 60 80 Burnup (MWD/MTU)
OFFICIAL USE ONLY PROPRIETARY INFORMATION
OFFICIAL USE ONLY PROPRIETARY INFORMATION Table 2-3 of Attachment 10 of the LAR dated July 6, 2018, indicates that ((
)). Additional information is needed to demonstrate how LHGR values are controlled to ensure that peak centerline melt is precluded and that variations in fuel type and ((
)) are accounted for in the calculations for UFSAR events 15.4.2 and 15.4.3.
SRXB RAl-3 The regulatory basis for this RAI is 10 CFR 50.46 and 10 CFR Part 50, Appendix K.
In Section 6.2, "DNB Propagation," of Attachment 10 of the LAR dated July 6, 2018, the licensee explains that the maximum cladding strain value cited in the NGF application for CE 14x14 is the limiting and bounding case for HTP' fuel. The LAR also claims that ((
)) therefore ((
)). ((
The LAR includes Figures 6-1 and 6-2, which provide ((
)) and ((
)) respectively.
)).
Because the criteria for DNB propagation is presented in terms of cladding strain, it is necessary to examine a comparison between Zr-4 and MS strain values.
- a.
Please provide data and an explanation that shows strain is bounded for Framatome CE16 HTP' fuel.
- b.
If sufficient dynamic strain data under representative cladding temperature ramp rate conditions does not exist to demonstrate that existing DNB propagation methods may be applied to Framatome HTP' fuel, then please provide an alternate means of
. addressing DNB propagation for Framatome HTP' fuel (e.g., consideration favorable pressure gradient across the cladding wall for the relevant set of events and exposure histories).
SRXB RAl-4 The regulatory basis for this RAI is 10 CFR 50.46 and 10 CFR Part 50, Appendix K.
The LAR dated July 6, 2018, presented information to demonstrate that the impact of MS cladding thermal conductivity and cladding specific heat were appropriately considered in the non-LOCA transient analysis system response computer codes CENTS and HERMITE.
However, the HERMITE code needs the heat conduction equation in the fuel pellet, gap and clad. Please clarify how the fuel specific input for the Framatome CE16 HTP' fuel was generated such that the fuel-to-clad gap coefficient of conductance was appropriately modeled, including any effects of gadolinium on the fuel-to-clad gap coefficient of conductance.
OFFICIAL USE ONLY PROPRIETARY INFORMATION
OFFICIAL USE ONLY PROPRIETARY INFORMATION SRXB RAl-5 The regulatory basis for this RAI is 10 CFR 50.46 and 10 CFR Part 50, Appendix K.
The approved method for utilizing statistical convolution to predict DNBR assumes a single fuel type. It is not clear how multiple fuel types with separate CHF correlations and probability density functions are considered in this analysis. Please provide additional information to clarify how mixed cores will be analyzed to determine DNBR. Discuss the methods as applied to a mixed core with both Framatome and Westinghouse fresh fuel bundles.
SRXB RAl-6 The regulatory basis for this RAI is 10 CFR 50.46 and 10 CFR Part 50, Appendix K.
- a.
The licensee's supplemental letter dated October 18, 2018, states, in part, that "for the Reference (3) application, APS will use interim criteria published by NRC staff in Standard Review Plan, Section 4.2, in 2007... with plant specific adjustments." It is not clear how this position will be implemented for mixed core scenarios. Please describe the intended application of the of interim criteria on mixed core scenarios.
- b.
For UFSAR event 15.4.8, the LAR dated July 6, 2018, states that, "One (1) change to methodology required: The methodology in CENPD-190-A is required to be modified to allow the use of COPERNIC fuel performance code instead of FATES." Section 6.5.1, "M5 Cladding Impact on CEA Ejection Analysis," states that ((
)). Confirm these are the only inputs and parameters that COPERNIC will be used for. Additionally, the interim criteria take into consideration the effect of burnup and are presented as a function of oxide/wall thickness for PWRs. Please describe (1) how burnup effects will be considered for both the Framatome and co-resident fuel and (2) which fuel performance codes will be used to determine the oxide/wall thickness and how the limiting fuel enthalpy rise is determined in a mixed core.
- c.
In Section 6.5.4.2, "Fuel Failure Evaluation Results," in Attachment 8 of the LAR, the licensee states the following, in part:
A comparison of the fuel failure percentage to the fuel failure percentage in the current UFSAR demonstrated that the fuel failure percentage for the CEA Ejection are bounded by the fuel failure percentages in the current PVNGS UFSAR Consequently, the offsite and control room dose consequences meet the acceptance criteria.
Please provide the results of this comparison and demonstrate that the current UFSAR results are bounding.
SRXB RAl-7 The regulatory basis for this RAI is 10 CFR Part 50, Appendix A, GDC 16, "Containment design"; GDC 38, "Containment heat removal"; and GDC 50, "Containment design basis."
OFFICIAL USE ONLY PROPRIETARY INFORMATION
OFFICIAL USE ONLY PROPRIETARY INFORMATION Section 8, "Containment Response Analysis," of Attachment 8, of the LAR dated July 6, 2018, discusses the parameters which are not affected by a change to Framatome CE16 HTP' fuel; however, there is no discussion regarding what has changed as a result of the fuel transition.
Describe any input changes to the mass and energy release analyses and describe how the analysis of record continues to remain valid for the main steam line break accident and LOCA.
V-APS RAl-01 VIPRE-01 Version Number What is the initial version and MOD of VIPRE-01 that APS is using to create its version of VIPRE-APS?
Associated Theory Manual Section Associated 10 CFR Part 50, Appendix A, GDC 1 O; 10 CFR 50.36; 10 CFR 50.34; and Regulations 10 CFR Part 50, Appendix B and Guidance SRP 15.0.2 Subsection 111.3.a V-APS RAl-02 Changes to VIPRE-01 Provide the complete list of changes between VIPRE-01 MOD 2.0 (the version of VIPRE-01 approved by the NRC staff) and the version of VIPRE-01, which was used to generate VIPRE-APS. Additionally, provide the justification for each change.
Associated Theory Manual Section Associated 10 CFR Part 50, Appendix A, GDC 10; 10 CFR 50.36;10 CFR 50.34, Regulations "Contents of applications; technical information"; and 1 O CFR Part 50, and Appendix B Guidance SRP 15.0.2 Subsection 111.3.a OFFICIAL USE ONLY PROPRIETARY INFORMATION
OFFICIAL USE ONLY PROPRIETARY INFORMATION V-APS RAl-03 Application of VIPRE-APS Confirm that VIPRE-APS will be used in a manner consistent with VIPRE-W as described in WCAP-14565-P-A/WCAP-15306-NP-A, "VIPRE-01 Modeling and Qualification for Pressurized Water Reactor Non-LOCA Thermal-hydraulic Safety Analysis," dated October 1999 (ADAMS Accession No. ML993160158).
Associated Theory Manual Section Associated 10 CFR Part 50, Appendix A, General Design Criterion 1 O; 10 CFR 50.36; Regulations 10 CFR 50.34; 10 CFR Part 50, Appendix B and Guidance SRP 15.0.2 Subsection 111.3.a V-APS RAl-04 Confirmation of Conditions and Limitations of VIPRE-01 Provide confirmation that the following conditions and limitations form VIPRE-01 MOD-1.0 and VIPRE-01 MOD-2.0 will be satisfied:
- a.
Confirm that the application of VIPRE-APS is limited to PWR licensing calculations with heat transfer regime up to CHF and will not exceed CHF.
- b.
Confirm that VIPRE-APS will abide by the quality assurance procedures described in Section 2.6 of the Safety Evaluation Report (SER) for VIPRE-01 MOD-1.
- c.
Confirm that VIPRE-APS will not be used in the following situations:
- i.
ii.
iii.
iv.
Associated Section Associated Regulations and Guidance Specific two-phase flow conditions that are characterized by large relative velocity between the phases or radical changes in flow regime, such as low-flow boil-off, annular flow, stratified two phase flow, or countercurrent flow.
Phenomena dominated by local pressure such as flow-down transient, boiling incepted at low pressure, or boiling-water reactor transient flow instability.
Free-field situations not dominated by wall friction.
Situations out of the applicable range of the constitutive correlations.
Previously Reviewed and Accepted Codes and Models 10 CFR Part 50, Appendix A, GDC 1 O; 10 CFR 50.36; 10 CFR 50.34; and 10 CFR Part 50, Appendix B OFFICIAL USE ONLY PROPRIETARY INFORMATION
V-APS RAl-05 OFFICIAL USE ONLY PROPRIETARY INFORMATION Benchmark Comparison Provide justification for the modeling options chosen for VIPRE-APS, including specific and justifying the two-phase friction multiplier.
Associated Validation of the Closure Relationships Section Associated 10 CFR Part 50, Appendix A, GDC 1 O; 10 CFR 50.36; 10 CFR 50.34; and Regulations 10 CFR Part 50, Appendix B and Guidance SRP 15.0.2 Subsection 111.3.b V-APS RAl-06 Single Version of the Evaluation Model (EM)
Confirm that all runs of VIPRE-APS were performed with a single version of the computer code and were implemented in a consistent manner.
Associated Single Version of the Evaluation Model Section Associated 10 CFR Part 50, Appendix A, GDC 1 O; 10 CFR 50.36; 10 CFR 50.34; and Regulations 10 CFR Part 50, Appendix B and Guidance SRP 15.0.2 Subsection 111.3.d V-APS RAl-07 Sensitivity Studies APS should confirm that the axial and radial noding used in the safety analysis is consistent with the methodology presented in VIPRE-W or perform sensitivity studies, which justify its chosen axial and radial noding.
Associated Single Version of the Evaluation Model Section Associated 10 CFR Part 50, Appendix A, GDC 1 O; 10 CFR 50.36; 10 CFR 50.34; and Regulations 10 CFR Part 50, Appendix B and Guidance SRP 15.0.2 Subsection 111.3.d OFFICIAL USE ONLY PROPRIETARY INFORMATION
BHTP RAl-01 OFFICIAL USE ONLY PROPRIETARY INFORMATION Measured to Predicted Comparison For BHTP implemented into both VIPRE-W and VIPRE-APS, describe the method of determining the measured CHF value from the experimental test data and the method of determining the predicted CHF value. Confirm that those methods are consistent with the method used in the initial approval of the BHTP correlation or justify the new method if it is different.
Goal G3.1 - Validation Error Associated Regulations 10 CFR Part 50, Appendix A, GDC 1 O; 10 CFR 50.36; 10 CFR 50.34; and and 10 CFR Part 50, Appendix B Guidance BHTP RAl-02 Validation Data Confirm that the same data that was used to validate BHTP in its initial submittal was also used to validate BHTP's performance in VIPRE-W and VIPRE-APS.
Goal G3.2.1 - Validation Data Associated Regulations 10 CFR Part 50, Appendix A, GDC 1 O; 10 CFR 50.36; 10 CFR 50.34; and and 10 CFR Part 50, Appendix B Guidance BHTP RAl-03 Expanded Range of BHTP Justify the use of the expanded application domain for the BHTP model for computer codes other than L YNXT.
Goal G3.2.2 Application Domain Associated Regulations 10 CFR Part 50, Appendix A, GDC 1 O; 10 CFR 50.36; 10 CFR 50.34; and and 10 CFR Part 50, Appendix B Guidance OFFICIAL USE ONLY PROPRIETARY INFORMATION
BHTP RAl-04 OFFICIAL USE ONLY PROPRIETARY INFORMATION Restricted Domain Describe the process used to restrict the BHTP CHF model to its application domain in both VIPRE-W and VIPRE-APS.
Goal G3.2.6 - Restricted Domain Associated Regulations 10 CFR Part 50, Appendix A, GDC 1 O; 10 CFR 50.36; 10 CFR 50.34; and and 10 CFR Part 50, Appendix B Guidance BHTP RAl-05 Poolability Examine the validation error (e.g., predicted to measured CHF) for potential inconsistences.
This should include examining the poolability of the different subgroups, especially the subgroup of data from the BHTP database that would be expected to have the most similar behavior to the CE16 HTP' fuel.
Confirm that all subgroups are poolable for both VIPRE-W and VIPRE-APS.
Goal G3.3.1 - Poolability Associated Regulations 10 CFR Part 50, Appendix A, GDC 1 O; 10 CFR 50.36; 10 CFR 50.34; and and 10 CFR Part 50, Appendix B Guidance OFFICIAL USE ONLY PROPRIETARY INFORMATION
BHTP RAl-06 OFFICIAL USE ONLY PROPRIETARY INFORMATION Non-Conservative Sub-Regions Examine the validation error (e.g., predicted to measured CHF) for possible non-conservative sub-regions. This should include examining the validation error expected to have the most similar behavior to the CE16 HTP' fuel.
Confirm that all there are no obvious non-conservative sub-regions with BHTP's application in both VIPRE-W and VIPRE-APS.
Goal G3.3.2 - Non-Conservative Sub-Regions Associated Regulations 10 CFR Part 50, Appendix A, GDC 1 O; 10 CFR 50.36; 10 CFR 50.34; and and 10 CFR Part 50, Appendix B Guidance BHTP RAl-07 Model Trends For both VIPRE-W and VIPRE-APS, provide plots demonstrating that the error in the BHTP (measured-to-predicted or predicted to measured) versus its key input parameters (e.g., pressure, local mass flux, local quality, shape factor) is consistent over the entire application domain and is adequately quantified by the 95/95 limit applied to BHTP.
Goal G3.3.3 - Model Trends Associated Regulations 10 CFR Part 50, Appendix A, GDC 1 O; 10 CFR 50.36; 10 CFR 50.34; and 10 CFR Part 50, Appendix B Guidance OFFICIAL USE ONLY PROPRIETARY INFORMATION
BHTP RAl-08 OFFICIAL USE ONLY PROPRIETARY INFORMATION Differences between VIPRE-APS and VIPRE-W Provide an explanation for the differences between VIPRE-APS and VIPRE-W predictions of the BHTP CHF data given in Figure 5-3 of the LAR dated July 6, 2018. While most of the predictions are nearly identical, a small number of the data points have differences, which are larger than anticipated and would indicate differences between VIPRE-APS and VIPRE-W.
Goal G3.3.3 Model Trends Associated Regulations 10 CFR Part 50, Appendix A, GDC 10; 10 CFR 50.36; 10 CFR 50.34; and and 10 CFR Part 50, Appendix B Guidance BHTP RAl-09 VIPRE-W Modeling Options Justify the new modeling options given in Table 5-7 of the LAR dated July 6, 2018, when applying BHTP and discuss how the originally approved modeling options will be applied when using another CHF model.
Goal G3.3.3 - Model Trends Associated Regulations 10 CFR Part 50, Appendix A, GDC 10; 10 CFR 50.36; 10 CFR 50.34; and and 10 CFR Part 50, Appendix B Guidance BHTP RAl-10 Same Evaluation Framework Confirm that future uses of the BHTP in both VIPRE-W and VIPRE-APS will be performed in a similar manner as was when generating the validation data presented in this LAR.
Goal G3.5.2 - Same Evaluation Framework Associated Regulations 10 CFR Part 50, Appendix A, GDC 10; 10 CFR 50.36; 10 CFR 50.34; and and 10 CFR Part 50, Appendix B Guidance OFFICIAL USE ONLY PROPRIETARY INFORMATION
CHF RAl-01 OFFICIAL USE ONLY PROPRIETARY INFORMATION CHF Model Below First HTP' Grid Spacer Provide justification for the conclusion that no CHF model is needed to predict the DNBR behavior below the first HTP' grid spacer.
Associated Modeling of HTP' fuel below the first HTP' grid spacer Section Associated Regulations 10 CFR Part 50, Appendix A, GDC 1 O; 10 CFR 50.36; 10 CFR 50.34; and and 10 CFR Part 50, Appendix B Guidance CHF RAl-02 Use of Macbeth at Low Pressures Provide a reference for Macbeth. The NRC staff is aware of an issue where older CHF models may under predict the CHF in the hot channel at low pressures. This is believed to be related to the fact that many of the older CHF correlations were based on tube data, and that at low pressures and low mass fluxes, the coolant is not kept inside the hot channel of an open lattice bundle as it would be in a tube. Justify the continued use of Macbeth given this new information.
Associated Modeling of HTP' fuel below the first HTP' grid spacer Section Associated Regulations 10 CFR Part 50, Appendix A, GDC 1 O; 10 CFR 50.36; 10 CFR 50.34; and and 10 CFR Part 50, Appendix B Guidance OFFICIAL USE ONLY PROPRIETARY INFORMATION
CHF RAl-03 OFFICIAL USE ONLY PROPRIETARY INFORMATION Use of WLOP CHF Correlation Justify the use of the Westinghouse Low-Pressure (WLOP) Correlation for use on fuel types of than those fuel types it initially validated, specifically CE16 HTP' fuel.
Associated Use of WLOP CHF Correlation Section Associated Regulations 10 CFR Part 50, Appendix A, GDC 10; 10 CFR 50.36; 10 CFR 50.34; and and 10 CFR Part 50, Appendix B Guidance CHF RAl-04 Application of Other CHF Model into Other Computer Codes When the NRC approves a CHF model, it is approved as a CHF model/subchannel code combination. The NRC staff recognizes that the behavior of the CHF model is dependent on the subchannel code's performance and limits the approval to the combination for which validation has been presented to the NRC. Typically, an applicant who desired to use a different CHF model in the same subchannel code, or the same CHF model in a different subchannel code will then submit an application to the NRC to change its approved methods.
APS has made such a submittal in this LAR. However, APS also stated in this LAR that they would like the ability to use other CHF model/subchannel code combinations, which have not been previously reviewed by the NRC staff.
APS should provide further details on the request of application of CHF models into subchannel codes without a submission to the NRC. Specifically, APS should list the complete set of combinations they may wish to use in the future, how they will demonstrate adequate validation to the NRC, and how they will maintain compliance with 10 CFR 50.36.
Associated Section Associated Regulations and Guidance Use of WLOP CHF Correlation 10 CFR Part 50, Appendix A, GDC 1 O; 10 CFR 50.36; 10 CFR 50.34; and 10 CFR Part 50, Appendix B OFFICIAL USE ONLY PROPRIETARY INFORMATION
MIX RAl-01 OFFICIAL USE ONLY PROPRIETARY INFORMATION Mixed Core APS has described a mixed core approach, which seems diff~rent from that described in the VIRPE-W topical report. APS should provide documentation and justification for its mixed core approach, including specification of any previous approvals. This approach should specify how the impact to DNBR behavior is calculated when a core contains multiple fuel types in a transition core (I.e., not a mixed fresh batch).
Associated Mixed Core Methodology Section Associated Regulations 10 CFR Part 50, Appendix A, GDC 1 O; 10 CFR 50.36; 10 CFR 50.34; and and 10 CFR Part 50, Appendix B Guidance MIX RAl-02 Mixed Core with Mixed Fresh Batch APS stated its intention to use its mixed core methodology for mixed fresh batches. APS should provide documentation and justification for this seemingly new application of a mixed core approach, including specification of any previous approvals. This approach should specify how the impact to DNBR behavior would be impacted by mixed fresh batches and would be calculated with mixed fresh batches. Additionally, APS should demonstrate that this approach is within the capabilities of the code and methodology.
Associated Mixed Core Methodology Section Associated Regulations 10 CFR Part 50, Appendix A, GDC 1 O; 10 CFR 50.36; 10 CFR 50.34; and and 10 CFR Part 50, Appendix B Guidance OFFICIAL USE ONLY PROPRIETARY INFORMATION
SET RAl-01 OFFICIAL USE ONLY PROPRIETARY INFORMATION Setpoints Methodology Describe how the BHTP CH F model will be implemented in the COLSS/CPCS setpoint methodology. This description should contain a description or reference to the currently approved process, as well as an explanation of the statistical methodology used.
Associated Application of COLSS/CPCS to Generate Setpoints for CE16 HTP' fuel Section Associated Regulations 10 CFR Part 50, Appendix A, GDC 10; 10 CFR 50.36; and 10 CFR 50.34 and Guidance TH RAl-01 Pressure Drop Provide a thermal hydraulic description of CE16STD, CE16NGF, and CE16 HTP' fuel that contains the number of grid spacers, and the elevation and pressure drop of the spacer, including the bottom grid.
Associated Thermal-hydraulic Compatibility Section Associated Regulations 10 CFR Part 50, Appendix A, GDC 1 O; 10 CFR 50.36; and 10 CFR 50.34 and Guidance OFFICIAL USE ONLY PROPRIETARY INFORMATION
TH RAl-02 OFFICIAL USE ONLY PROPRIETARY INFORMATION Scram Time Testing Confirm that scram time testing will validate the similarity between Westinghouse and Framatome fuel and will demonstrate that the control element assembly drop time will not be challenged due to the fuel transition.
Associated Thermal-hydraulic Compatibility Section Associated Regulations 10 CFR Part 50, Appendix A, GDC 1 O; 10 CFR 50.36, 10 CFR 50.34 and Guidance TH RAl-03 Guide Tube Heating Provide details of the analysis which confirms there will be no boiling in the guide tubes.
Associated Thermal-hydraulic Compatibility Section Associated Regulations 10 CFR Part 50, Appendix A, GDC 1 O; 10 CFR 50.36; and 10 CFR 50.34 and Guidance OFFICIAL USE ONLY PROPRIETARY INFORMATION
Proprietary: ML19234A321; RidsRgn4MailCenter Resource PClifford, NRR MPanicker, NRR DWoodyatt, NRR Jlehning, NRR JKaizer, NRR RGrover, NRR Non-Proonetary: ML19234A320; via memo OFFICE NRR/DORL/LPL4/PM NRR/DORL/LPL4/LA NRR/DSS/SNPB/BC* NRR/DSS/SRXB/BC(A)*
NAME Slingam PBlechman Rlukes JBorromeo DATE 08/29/19 08/29/19 08/07/19 08/07/19 OFFICE NRR/DSS/STSB/BC(A)* NRR/D0RL/LPL4/BC NRR/DORL/LPL4/PM NAME PSnyder RPascarelli SLingam DATE 08/07/19 08/29/19 08/29/19