Document: NUREG-0800
Document ID: ba716f3a-da21-413e-a855-dc0255b76522
Document Type: srp
Title: PUMP FLYWHEEL INTEGRITY (PWR)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1006/ML100680157.pdf
Revision Date: 2023-06
Chapter: 5
Section ID: 5.4.1.1
CFR Part: 
CFR Title: 

Content:
ccident, and the safe shutdown earthquake without loss of structural integrity. The design of the pump flywheel should also meet the following criteria: 5.4.1.1-6 Revision 3 - May 2010 A. The combined stresses at the normal operating speed due to centrifugal forces and the interference fit of the wheel on the shaft, should not exceed 1/3 of the minimum specified yield strength or 1/3 of the measured yield strength in the weak direction of the material if appropriate tensile tests have been performed on the actual material of the flywheel. B. The design overspeed of a flywheel should be at least ten percent above the highest anticipated overspeed. The anticipated overspeed should include consideration of the maximum rotational speed of the flywheel if a break occurs in the reactor coolant piping in either the suction or discharge side of the pump. An acceptable basis for the assumed design overspeed, addressing pipe breaks consistent with the design basis for reactor coolant piping, should be submitted to the staff for review. C. The combined stresses at the design overspeed, due to centrifugal forces and the interference fit, should not exceed 2/3 of the minimum specified yield strength, or 2/3 of the measured yield strength in the weak direction if appropriate tensile tests have been performed on the actual material of the flywheel. D. The shaft and the bearings supporting the flywheel should be able to withstand any combination of loads from normal operation, anticipated transients, the design basis loss-of-coolant accident, and the safe shutdown earthquake. E. A fracture mechanics analysis should be conducted for the life time of the flywheel, including extended operation, to predict the critical speed for fracture of the flywheel. The ratio of KIC to the maximum tangential stress at speeds from normal to design overspeed should be at least 2 /in (consistent with SRP Section 10.2.3, ATurbine Disk Integrity@), or alternatively, the ratio of KIC to the applied K