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:
rocedures used t o perform each o f these processes are t o be documented. A good example i s given i n Chapter 7 o f Reference 3. Portions o f t h a t analysis, or other analyses, may be referenced i n l i e u o f por- tions o f the analysis described i n t h i s chapter, provided the licensee demon- strates the appl icabi 1 i t y o f the referenced analyses t o the specific plant. 7.1 Sensitivity Analysis Perform a s e n s i t i v i t y analysis t o estimate the change i n the through-wall crack frequency f o r a known change o f a single parameter. Parameters examined i n the s e n s i t i v i t y analysis should include (1) the i n i t i a t i n g event and event tree branch frequencies, (2) the thermal -hydraul i c variabl es (temperature, pres- sure, etc. ), and (3) the fracture mechanics variables (fluence, flaw density, etc.). Where appropriate, 68th percentile (1-sigma) values should be used t o represent the change i n the parameter. This should provide a s u f f i c i e n t change t o i l l u s t r a t e the effects o f the change, and the use o f the 68th percentile value whenever possible w i l l help t o define the important v a r i a b i l i t i e s . I n the case o f temperature and pressure, however, the 68th percentile values may vary from one sequence t o another. I n t h i s case, it may be easier t o i d e n t i f y a representative change i n the parameter t h a t could then be used f o r a l l sequences rather than t o t r y t o use the 68th percentile values. 1. Each variable examined i n the s e n s i t i v i t y analysis should be l i s t e d along w i t h the change i n the variable. I n the cases i n which changes are represented by using 68th percentile values, some explanation should be provided t o document the reasons the value i s considered a 68th percentile value. I n those cases i n which something other than a 68th percentile value i s chosen, discussion should center around the reasons f o r choosing the value used. Sensitivity