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:
“design limits for fission product barriers” to be consistent with the AOO acceptance criteria. ARDC 10 and ARDC 15 provide the appropriate design limits for the fuel and reactor coolant boundary, respectively. A non-LWR may not necessarily shut down rapidly (within seconds) but the shutdown should occur in a time frame such that the fission product barrier design limits are not exceeded. In regards to safety class, the capability to shut down the reactor is identified as a function performed by safety- related SSCs in the 10 CFR 50.2 definition of safety-related SSCs. (2) Current GDC 27 states that the reactivity control systems shall be designed to have a combined capability of reliably controlling reactivity changes to assure that, under postulated accident conditions and with appropriate margin for stuck rods, the capability to cool the core is maintained. Reliably controlling reactivity, as required by GDC 27, requires that the reactor achieve and maintain safe, stable conditions, including subcriticality, using only safety related equipment with margin for stuck rods (Ref. 26). The first sentence of ARDC 26 (2) refers to the safety-related APPENDIX C. MODULAR HIGH-TEMPERATURE GAS-COOLED REACTOR DESIGN CRITERIA Appendix C to DG-1330, Page C-13 III. Reactivity Control Criterion mHTGR-DC Title and Content NRC Rationale for Adaptions to GDC means (systems and/or mechanisms) to achieve and maintain safe shutdown. “Maintain safe shutdown” indicates subcriticality in the long term or an equilibrium condition naturally achieved by the design. The staff changed “reactivity control systems” to “means” in recognition that advanced reactor designs may rely on a system, inherent feedback mechanism, or some combination thereof to shut down the reactor and maintain a safe shutdown under design-basis event conditions. SECY-94-084, “Policy and Technical Issues Associated with the Regulatory Treatment of Non-Safety Systems in Passive Plant Designs” (Ref.