ML25049A234
| ML25049A234 | |
| Person / Time | |
|---|---|
| Site: | Westinghouse |
| Issue date: | 02/18/2025 |
| From: | Ekaterina Lenning Licensing Processes Branch |
| To: | Zozula C Westinghouse |
| References | |
| WCAP-18869-P, Rev. 0, WCAP-18869-NP, Rev. 0 | |
| Download: ML25049A234 (1) | |
Text
OFFICIAL USE ONLY - PROPRIETARY INFORMATION 1
OFFICIAL USE ONLY - PROPRIETARY INFORMATION REQUEST FOR ADDITIONAL INFORMATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION WESTINGHOUSE ELECTRIC COMPANY TOPICAL REPORT WCAP-18869-P/NP, REVISION 0, "HIGH PERFORMANCE CLADDING FOR USE IN BOILING WATER REACTOR FUEL" DOCKET NO. 99902038 ISSUE DATE: 02/18/2025
=
Background===
By letter dated March 8, 2024 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML24072A267), Westinghouse Electric Company submitted Topical Report (TR) WCAP-18869-P/NP, Revision 0, High Performance Cladding for Use in Boiling Water Reactor Fuel, for U. S. Nuclear Regulatory Commission (NRC) review and approval.
Upon review of the submittal and completion of the regulatory audit that was conducted on December 12-13, 2024, the NRC staff has determined that the following additional information is necessary to continue the review. Westinghouse indicated via an email dated February 18, 2025, that responses to the NRC requests for additional information (RAIs) will be submitted to the NRC within 60 days from the receipt of the RAIs.
Regulatory Basis Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Domestic Licensing of Production and Utilization Facilities, contains the general design criteria (GDC) described in Appendix A to Part 50 including GDC 10, Reactor design, GDC 25, Protection system requirements for reactivity control malfunctions, GDC 26, Reactivity control system redundancy and capability, GDC 27, Combined reactivity control systems capability, GDC 28, Reactivity limits, and GDC 35, Emergency core cooling. Regulatory guidance for the review of fuel system designs and adherence to these GDCs is provided in NUREG-0800, Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants - LWR Edition (SRP). Specifically, Section 4.2, Fuel System Design. Additionally, SRP Section 4.3, Nuclear Design, and Section 4.4, Thermal and Hydraulic Design, are pertinent to the review of fuel systems.
GDC 10 states:
The reactor core and associated coolant, control, and protection systems shall be designed with the appropriate margin to assure that specified acceptable fuel design limits are not exceeded during any condition of normal operation, including the effects of anticipated operational occurrences.
GDC 10 establishes specified acceptable fuel design limits to ensure that the fuel is not damaged. That means that fuel rods do not fail, fuel system dimensions remain within operational tolerances, and functional capabilities are not reduced below those assumed in the safety analysis. SRP Section 4.2 acceptance criteria are based on meeting the requirements of GDC 10.
OFFICIAL USE ONLY - PROPRIETARY INFORMATION 2
OFFICIAL USE ONLY - PROPRIETARY INFORMATION Requirements for analyzing the design-basis loss-of-coolant accident (LOCA) are provided in 10 CFR 50.46, Appendix K to 10 CFR Part 50, and GDC 35. The most relevant regulations to this review are:
- Per 10 CFR 50.46(a)(1)(i), each boiling or pressurized light-water nuclear power reactor fueled with uranium oxide pellets within cylindrical zircaloy or ZIRLOTM cladding must be provided with an emergency core cooling system (ECCS) that must be designed so that its calculated cooling performance following postulated LOCAs conforms to the criteria set forth in Section 50.46(b). ECCS cooling performance must be calculated in accordance with an acceptable evaluation model and must be calculated for a number of postulated LOCAs of different sizes, locations, and other properties sufficient to provide assurance that the most severe postulated LOCAs are calculated.
- 10 CFR Part 50, Appendix K, sets forth the documentation requirements for each evaluation model, and establishes required and acceptable features of evaluation models for heat removal by the ECCS.
- GDC 35 requires abundant core cooling sufficient to (1) prevent fuel and cladding damage that could interfere with effective core cooling and (2) limit the metal-water reaction on the fuel cladding to negligible amounts. GDC 35 further requires suitable redundancy of the ECCS, such that it can accomplish its design functions, assuming a single failure, irrespective of whether its electrical power is supplied from offsite or onsite sources.
In accordance with SRP Section 4.2, Fuel System Design, the objectives of the fuel system safety review are to provide assurance that:
- a. The fuel system is not damaged as a result of normal operation and anticipated operational occurrences (AOOs),
- b. Fuel system damage is never so severe as to prevent control rod insertion when it is
- required,
- c. The number of fuel rod failures is not underestimated for postulated accidents, and
- d. Coolability is always maintained.
SRP Section 6.2.1, Containment Functional Design, presents information related to containment integrity following postulated LOCA, steam line, or feedline break accidents as impacted by the HiFi cladding on the above analyses.
SRP Chapter 15, Transient and Accident Analyses, including acceptance criteria for AOOs and postulated accidents and their impact on HiFi cladding, is addressed in the TR. The review of this TR is based on the acceptance criteria for each of the events described in SRP Chapter 15.
Question 1 Please provide any additional data that was collected since publication of the submitted TR for all lead test rod (LTR)/post irradiation examination programs for HiFi cladding.
Question 2 For the BWR reactor coolant chemistry control programs in the U.S. that are not a part of the Westinghouse LTR program, or not specifically tested for this study, please justify why those chemistry control programs are not expected to have a negative effect on the performance of HiFi cladding (cladding corrosion, hydrogen pickup, etc.). If possible, please provide response in a format which lists the program vs. the effect on HiFi cladding.
OFFICIAL USE ONLY - PROPRIETARY INFORMATION 3
OFFICIAL USE ONLY - PROPRIETARY INFORMATION Question 3 What is the models' uncertainty of HiFi cladding predicted oxide thickness that justifies using
[..-........................]
Conversely, if this data and discussion are to be included in the specific fuel bundle design reports, please clarify this method of inclusion.
Question 4 Please provide detailed model and data analysis to justify the use of [
..-................................-........] including the data discussed during the NRC regulatory audit of TR WCAP-18869-P/NP, High Performance Cladding for Use in Boiling Water Reactor Fuel, conducted by the NRC staff on December 12-13, 2024.
Question 5 The following are related to the impact of high-performance cladding response to LOCA and associated analyses:
a) Please provide the detailed data and analysis of the impact of iron on the +
transformation temperature that justifies [ ] including the data discussed during the NRC regulatory audit.
b) Please provide a [
.............. ] Also, please describe how flow blockage is determined from predicted burst strains for HiFi cladding. Conversely, if this data and discussion are to be outside this TR, then please clarify how this information will be addressed.
Question 6 What are the textures and second phase particle (SPP) size distributions for the different lead use assemblys (LUAs) cladding with HiFi?
Question 7 What fabrication specifications will be applied to texture and SPPs for HiFi cladding in production and how do these compare to current generation Zr-2 specifications for the fuel rods?
Other than the material composition, [
...........,................,....................................................-.?] If yes, what are they and what
[ ]
Question 8 Please provide detailed data for the fuel rod design (FRD) criteria along with the evaluations of the use of HiFi cladding on the specific criteria (Section 4.2 of TR WCAP-18869-P/NP, Revision 0). This should also include all discussions of Westinghouse acceptance criteria for FRD.
OFFICIAL USE ONLY - PROPRIETARY INFORMATION 4
OFFICIAL USE ONLY - PROPRIETARY INFORMATION Question 9 Please confirm that all the performance acceptance criteria and material limits [
...........] and identify where they are addressed.
OFFICE NRR/DORL/LLPB/
PM NRR/DORL/LLPB/
BC NRR/DORL/LLPB/
LA NRR/DSS/SFNB/
BC NAME ELenning GGeorge DHarrison SKrepel DATE 02/18/2025 02/18/2025 2/14/2025 02/11/2025 OFFICIAL RECORD COPY