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:
REVIEW RESPONSIBILITIES Primary - Organization responsible for the review of materials engineering issues related to flaw evaluation and welding Secondary - None I. AREAS OF REVIEW General Design Criterion (GDC) 4 of Appendix A to Title 10 of the Code of Federal Regulations, Part 50 (10 CFR Part 50) requires that structures, systems, and components (SSCs) of nuclear power plants important to safety be protected against the effects of missiles that might result from equipment failures. Because flywheels have large masses and rotate at speeds of 900 revolutions per minute (rpm) or 1200 rpm during normal reactor operation, a loss of flywheel integrity could result in high energy missiles and excessive vibration of the reactor coolant pump assembly. The safety consequences could be significant because of possible damage to the reactor coolant system, the containment, or the engineered safety features. GDC 1 and 10 CFR Part 50.55a(a)(1) require that SSCs important to safety shall be designed, fabricated, erected and tested to quality standards which shall be identified and evaluated to determine their applicability, adequacy, and sufficiency to assure a quality product in keeping with the required safety function. Reactor coolant pump flywheel failure can result in reduction or loss of forced coolant flow. 5.4.1.1-2 Revision 3 - May 2010 The specific areas of review are as follows: 1. Materials Selection and Fabrication. Reactor coolant pump flywheels are of a simple geometric shape, and are made of ductile material. Their quality can be closely controlled and their service conditions are not severe. Therefore, the use of suitable material and fabrication, coupled with adequate design and inservice inspection can provide a sufficiently small probability of a flywheel failure that the consequences of failure need not be protected against. Information in the applicant's safety analysis report (SAR) on materials selection and the procedures used to minimize flaws and