ML24291A117
| ML24291A117 | |
| Person / Time | |
|---|---|
| Issue date: | 10/23/2024 |
| From: | Matthew Sunseri Advisory Committee on Reactor Safeguards |
| To: | Walter Kirchner Advisory Committee on Reactor Safeguards |
| References | |
| Download: ML24291A117 (1) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION ADVISORY COMMITTEE ON REACTOR SAFEGUARDS WASHINGTON, DC 20555 - 0001 MEMORANDUM TO:
Walt Kirchner, Chair NuScale Subcommittee Advisory Committee on Reactor Safeguards FROM:
Matthew Sunseri, Member NuScale Subcommittee Advisory Committee on Reactor Safeguards
SUBJECT:
INPUT FOR ACRS REVIEW OF THE NUSCALE STANDARD DESIGN APPROVAL APPLICATION - SAFETY EVALUATION REPORT FOR CHAPTER 9, AUXILIARY SYSTEMS In response to the Subcommittees request, I have reviewed the NRC staffs safety evaluation report (SER) provided to support ACRS review of the standard design approval application (SDAA), and the associated section of the applicants submittal for Chapter 9, Auxiliary Systems. The following is my recommended course of action concerning further review of this chapter and the staffs associated safety evaluation.
SER Summary Chapter 9 discusses a wide range of systems supporting the NuScale design including: nuclear fuel storage and handling; water systems such as station service, reactor component cooling, demineralized, site cooling, chilled, utility, and the ultimate heat sink; process auxiliary systems such as chemical and volume control, containment flooding and drain, and standby liquid control; heating, ventilation and air conditioning systems; and other systems such as fire protection. These systems design and functions generally follow the approved NuScale design certification with minor exceptions and scaling changes.
One notable change involves the size of the ultimate heat sink. The pool forming the ultimate heat sink was not only reduced commensurate with the sizing for 6 versus 12 modules but also the water height was lowered. It is counter intuitive that the water level would need to be lowered (and thus giving up margin for longer term shutdown cooling); however, due to changes in the way the emergency core cooling system functions in some scenarios NuScale found it necessary to reduce the water borne heat transfer area of the containment in order to avoid over cooling the core. We find this change to be acceptable.
Finally, NuScale reduced the number of important human actions. The impact of these changes will be discussed in our review of Chapter 18.
10/23/24 MATTHEW SUNSERI Digitally signed by MATTHEW SUNSERI Date: 2024.10.23 14:47:28 -04'00'
W. Kirchner Staff SE The staffs review was thorough, and their assessment found that the NuScale design and associated combined license items met regulatory criteria.
Concerns I did not identify any specific deficiencies or concerns in my review. The application was well documented, and the staffs evaluation thorough.
Recommendation As lead reviewer for NuScale Chapter 9, I recommend that the Committee not perform any additional review of this chapter.
References
- 1. U. S. Nuclear Regulatory Commission, Safety Evaluation of NuScale SDAA Chapter 9, Auxiliary Systems, August 19, 2024 (ADAMS Accession No. ML24158A069).
- 2. NuScale Power, LLC, Standard Design Approval Application, Part 2, Chapter 9, Auxiliary Systems, Revision 1, October 31, 2023 (ADAMS Accession No. ML23304A355).
SUBJECT:
INPUT FOR ACRS REVIEW OF THE NUSCALE STANDARD DESIGN APPROVAL APPLICATION - SAFETY EVALUATION REPORT FOR CHAPTER 9, AUXILIARY SYSTEMS Package Accession No: ML24291A111 Accession No: ML24291A117 Publicly Available (Y/N): Y Sensitive (Y/N): N If Sensitive, which category?
Viewing Rights:
NRC Users or ACRS only or See restricted distribution OFFICE ACRS SUNSI Review ACRS ACRS NAME MSnodderly MSnodderly LBurkhart MSunseri DATE 10/8/24 10/8/24 10/8/24 10/17/24 OFFICIAL RECORD COPY 10/23/24