Document: NRC Regulatory Guide
Document ID: 8a2332d3-66ca-40af-84e1-507db8b26559
Document Type: regulatory_guide
Title: TRIAL - Acceptability of Probabilistic Risk Assessment Results for Non-Light Water Reactor Risk-Informed Activities
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2123/ML21235A008.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.247
CFR Part: 
CFR Title: 

Content:
leading to loss of heat sink or radionuclide transport barrier bypass require a greater number of spurious operations to be included in the fire plant response model). • Instrumentation and support equipment are included. • The internal fire PRA model for each POS should be evaluated for the need for different or additional equipment, particularly in the case of spurious actuations. • The uncertainties in the internal fire PRA related to the internal fire-initiating events and equipment selection are identified and characterized. The objective of the internal fire cable selection and location is to identify those cables associated with the equipment identified in the internal fire-initiating event and equipment selection technical element. The selected cables are mapped to the PAUs and, in some cases, to electrical raceways. The ability to locate a cable for the internal fire PRA is limited by the information known about the plant (i.e., the lack of as-built details) prior to construction. The location of cables is not generally affected by the particular POS, unless cables are temporarily routed during that POS. The characteristics and attributes needed to achieve the objectives of an internal fire cable selection and location PRA analysis element are as follows: • Cables that are required to support the operation of equipment represented in the internal fire PRA (defined in the equipment selection element) are identified and located. RG 1.247, Page 29 • The ability to locate a cable for the internal fire PRA is limited by the information known about the plant (i.e., the lack of as-built details) prior to construction. • The location of cables is not generally affected by the POS, unless cables are temporarily routed during the POS. • The uncertainties in the internal fire PRA related to cable selection are identified and characterized. The objective of the internal fire qualitative screening is to eliminate certain PAUs defined in the plant boundary