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:
ulic models, fracture mechanics models, grouping of sequences both for thermal-hydraulic analysis and fracture mechanics analysis, nodalization i n the thermal-hydraulic models, etc. These assumptions can introduce conservative or nonconservative biases into the analysis. These biases should be identified and their potential impact on the results discussed. In this section, important assumptions made as part of the analysis should be 1 isted. Each assumption should be identified as being either conservative or nonconservative. A discussion should be supplied for each assumption w i t h respect t o i t s impact on the overall value of through-wall crack frequency. Whenever excess conservatism or nonconservatism i s suspected to be present i n an assumption, an alternative assumption should also be used in the full calcu- lation procedure and the impacts on the overall result compared. 8. EFFECT OF CORRECTIVE ACTIONS ON VESSEL THROUGH-WALL CRACK FREQUENCY This chapter i s t o summarize the licensee's program o f corrective measures. Each corrective measure considered by the licensee should be presented and ex- plained. I n each case, the reasons f o r considering the action as a corrective measure are t o be documented, and the estimated impact o f the action with respect t o through-wall crack frequency provided. Corrective actions t h a t are t o be considered include, but are not l i m i t e d to, those discussed i n the remaining sections o f the chapter. An example can be found i n Chapter 8 o f Reference 3. 8.1 F l ux Reduction Program Early analysis and implementation o f such flux reductions as are reasonably practicable t o avoid reaching the screening c r i t e r i o n are already being required and accomplished i n accordance with the PTS rule, § 50.61. Further f l u x reduc- tions t o c r i t i c a l areas o f the vessel wall t h a t would reduce the r i s k o f con- tinued operation beyond the screening c r i t e r i o n should be considered. I f such