Document: NRC Regulatory Guide
Document ID: da2e0703-3488-44b0-b6d0-089aac7cae3d
Document Type: regulatory_guide
Title: Format and Content of Plant-Specific Pressurized Thermal Shock Safety Analysis Reports for Pressurized Water Reactors
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0037/ML003740028.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.154
CFR Part: 
CFR Title: 

Content:
s o f i n i t i a t o r s that should be included are: O Loss-of-coolant accidents ( LOCAs) , i ncl udi ng steam generator tube rupture accidents. * Steam 1 i ne breaks. O Overfeeds. O Combinations of these, i ncl uding possible return t o c r i t i c a l i ty. 3.2.2 I d e n t i f i c a t i o n o f Important I n i t i a t o r Variations - After the classes o f potential i n i t i a t o r s have been identified, it i s i m - portant t o consider variations within any individual class. These variations should include: 1. Decay heat level - The decay heat level, determined by recent operat- ing history o f the plant, can have a major impact on the potential consequences o f a given event. Thus, various decay heat conditions should be considered. Clearly, decay heat associated with a reactor t r i p from f u l l power (assuming operation a t f u l l power f o r some considerable time) should be examined. Zero decay heat represents the opposite extreme but f o r a l l practical purposes occurs only once a t the beginning o f l i f e f o r the plant when PTS i s not important. Therefore, the analyst may choose t o use some other level o f decay heat t h a t would cover potential decay heat conditions a f t e r the i n i t i a l startup o f the plant. The reasons f o r choosing particular decay heat levels f o r analysis should be documented. Each i d e n t i f i e d i n i t i a t o r should be examined a t a l l decay heat levels defined whenever appropriate. 2. Power level - Power level may be important since certain equipment conditions o r configurations may only e x i s t a t certain power levels, e.g., hot standby. As i n the case of decay heat level identification, the reasons f o r the selection o f specific power levels f o r analysis purposes should be stated. It should be noted t h a t under certain conditions a reactor system may be a t a high power level with a low decay heat condition. 3. Location o f event - I n many instances the location o f the event i s