Document: NRC Regulatory Guide
Document ID: da269da5-7390-4252-b08f-bdb7aeb8beaf
Document Type: regulatory_guide
Title: Developing Principal Design Criteria for Non-Light Water Reactors + HISTORY - HISTORY 02/2017 – DG-1330 , Proposed Revision 0
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1630/ML16301A307.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.232
CFR Part: 
CFR Title: 

Content:
must be satisfied during AOOs and design-basis accidents, as well as during normal operating and shutdown conditions. 79 Cover gas inventory maintenance. A system to maintain cover gas inventory shall be provided as necessary to ensure that the primary coolant sodium design limits are not exceeded as a result of cover gas loss due to leakage from the primary coolant boundary and rupture of small piping or other small components that are part of the primary coolant boundary. This criterion is similar to GDC 33 in 10 CFR Part 50, Appendix A and SFR-DC 33 in this document. GDC 33 and SFR-DC 33 focus on the effects of primary coolant (sodium) loss. A leak in a SFR primary coolant system may expel the cover gas rather than the primary coolant. The cover gas in the SFR performs an important to safety function by protecting the sodium coolant from chemical reactions. The staff created a new SFR-DC rather than adding the cover gas in the term “primary coolant.” The term “primary coolant sodium design limits” is used to maintain consistent terminology with SFR-DC 71. The primary coolant sodium design limits consider the possibility of interactions between the primary coolant sodium and the primary coolant boundary or the fuel due to changes in the chemistry of the primary coolant sodium. The considerations include the possibility of (1) chemical attack, (2) fouling and plugging of passages, (3) radionuclide concentrations, and (4) air or moisture ingress as a result of a leak of cover gas. The term “as necessary” is retained from SFR-DC 33 to permit designer flexibility if leakage of the system does not challenge the design limits of the primary coolant (for instance, an inerted containment filled with Argon). “Reactor coolant pressure boundary” has been relabeled as “primary coolant boundary” to conform to standard terms used in the LMR industry. APPENDIX B. SODIUM-COOLED FAST REACTOR DESIGN CRITERIA Appendix B to DG-1330, Page B-35 VII. Additional