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:
imits as described in the rationale to mHTGR-DC 10. The mHTGR-DC 34 incorporates the postulated accident residual heat removal requirements contained in GDC 35. Effective core cooling under postulated accident conditions is defined as maintaining fuel temperature limits below design values to help ensure the siting regulatory dose limits criteria at the exclusion area boundary (EAB) and low-population zone (LPZ) are not exceeded and a geometry is preserved which supports residual heat removal. The GDC reference to electric power was removed. Refer to the rationale for ARDC 17 on electric power systems. 35 Emergency core cooling. Not applicable to mHTGR. In the mHTGR design the power density and large length to diameter ratio are such that maintaining the helium coolant inventory is not necessary to maintain effective core cooling. Postulated accident heat removal is accomplished by the residual heat removal system described in mHTGR DC 34. APPENDIX C. MODULAR HIGH-TEMPERATURE GAS-COOLED REACTOR DESIGN CRITERIA Appendix C to DG-1330, Page C-18 IV. Fluid Systems Criterion mHTGR-DC Title and Content NRC Rationale for Adaptions to GDC 36 Inspection of passive residual heat removal system. The passive residual heat removal shall be designed to permit appropriate periodic inspection of important components to ensure the integrity and capability of the system. The word “passive” was added, based on the definition of a mHTGR. In definitions Section 3.1 of DOE report titled “Guidance for Developing Principal Design Criteria for Advanced (Non- Light-Water) Reactors” (Ref. 17), the mHTGR design has a low power density and hence residual heat is removed by a passive system. The GDC 36 system is renamed and revised to provide for inspection of the residual heat removal systems as required for mHTGR-DC 34. The list of examples was deleted, as they apply to LWR designs and each specific design will have different important components associated with residual heat removal.