Document: NRC Regulatory Guide
Document ID: cf64153e-7623-469c-a3f9-b57ba0f5497d
Document Type: regulatory_guide
Title: Reactor Coolant Pump Flywheel Integrity + HISTORY - HISTORY 01/2006 – Periodic Review of Revision 1 – No Issues Identified
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0037/ML003739936.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.14
CFR Part: 
CFR Title: 

Content:
arly revision. 21, Attention: Director, Office of Standards Development. Revision 1 Au"ust 1975 The non-ductile fracture analysis called for in regulatory position C.2.d should be based on appropriate conservative assumptions for stress level, flaw size, temperature, and fracture toughness at the location of interest. The non-ductile fracture criterion used to predict the critical fracture speed should be based on initial instability of the flaw as defined in ASTM E-399. The justification for the stress analysis method used in the fracture analysis should describe the treatment of stresses arising from interference fits and thermal stresses when they are superimposed on the stresses caused by rotational forces. Justification for the flaw size estimate should consider it to be the maximum expected size of flaw that could conceivably escape detection, and should consider material thickness, method and frequency of nondestructive inspection, and analysis of flaw growth in fatigue if that is significant. The effect of cracks emanating from such structural discontinuities as key ways and bolt holes should be evaluated. Justification for the fracture toughness assumed for the material should describe the properties to be measured transverse to the rolling direction in the tests of each plate of material. The range of fracture toughness test tempera tures should include the lowest service temperature at which overspeed could occur. If not, the basis used for any extrapolation should be justified. In doing the fracture analysis described in regulatory position C.2.d, engineering judgment should be used to select for analysis only those locations that appear to have the most severe sets of conditions. Severity is a function of stress level, flaw size, and fracture toughness at the location of interest. Comparison of perhaps three or four cases in terms of KI/KIC, the ratio of the imposed stress intensity factor at some nominal speed to the material toughness, should locate