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:
rial should be of closely controlled quality. Plates' should conform to ASTM A20 and should be produced by the vacuum-melting and degassing process or the electroslag remelting process. Plate material should be cross-rolled to a ratio of at least 1 to 3. b. Fracture toughness and tensile properties of each plate of flywheel material should be checked by tests that yield results2 suitable to confirm the applica bility to that flywheel of the properties used in the fracture analyses called for in regulatory positions C.2.c, d, and e. c. All flame-cut surfaces should be removed by machining to a depth at least 12 mm (1/2 inch) below the flame-cut surface. d. Welding, including tack welding and repair welding, should not be permitted in the finished flywheel unless the welds are inspectable and considered as potential sources of flaws in the fracture analysis. 2. Design a. The flywheel assembly, including any speed limiting and antirotation devices, the shaft, and the bearings, should be designed to withstand normal condi tions, anticipated transients, the design basis loss-of coolant accident, and the Safe Shutdown Earthquake loads without loss of structural integrity. b. Design speed should be at least 125% of normal speed but not less than the speed that could be attained during a turbine overspeed transient. Normal speed is defined as the synchronous speed of the a.c. drive motor at 60 hertz. c. An analysis should be conducted to predict the critical speed for ductile fracture of the flywheel. The methods and limits of paragraph F-1323.1(b) in Section III of the ASME Code are acceptable. If another method 2These results should be included as part of the'FSAR. 1.14-2 is used, justification should be provided. The anal ,sis should be submitted to the NRC staff for evaluation.7 d. An analysis should be conducted to predict the critical speed for nonductile fracture of the flywheel. Justification should be given for the stress analysis method, the estimate of flaw size