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:
d- ered in the determination of failure. Warm prestress should not be assumed in evaluations of the postulated transients. Acceptable types of material pro- perties are given in the study of the H. B. Robinson reactor (Ref. 3). In the Monte Carlo portion of the analysis, as a minimum, each of the following should be assigned distribution functions: KIc = Static crack initiation fracture toughness KIa = Crack arrest fracture toughness RTNDT = Ni 1 -ducti 1 i ty reference temperature Cu = Concentration of copper, wt-% Ni = Concentration of nickel, wt-% F = Fast neutron fluence The functions used should be justified. Examples of these distributions are found in Reference 3. The following additional information should be supplied: / 1. Flaw density - The number o f cracks per u n i t surface area should be established f o r use i n the calculations and should be j u s t i f i e d . A value o f 0.2 flaw per square meter o f 8-inch-thick material (one flaw/cubic meter) was selected i n References 1, 2, and 3. 2. Flaw depth density function - The flaw depth density d i s t r i b u t i o n should be established. The function t o be used can be t h a t specified i n References 1, 2, and 3. 3. Flaw size, shape, and location - Axial flaws w i t h depths less than 20 percent o f the wall thickness and a l l circumferential flaws should be modeled i n i n f i n i t e length. Axial flaws with depths greater than 20 percent o f the wall thickness may be modeled i n i n f i n i t e o r f i n i t e length depending on the r e l a t i v e toughness o f the weld regions and plate material. For instance, the length o f an axial flaw i n an axial weld t h a t suffers severe radiation damage r e l a t i v e t o the plate can be l i m i t e d t o the length o f the weld. The flaws should be assumed t o be located a t the inner surface o f the vessel and should extend through the cladding t o the inner surface o f the vessel. Reference 20 provides a comprehensive discussion o f