Document: NUREG-0800
Document ID: 90914152-fc84-4413-a5f5-aa75efd21205
Document Type: srp
Title: TURBINE MISSILES
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0636/ML063600395.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.5.1.3
CFR Part: 
CFR Title: 

Content:
and cleaned, and bore diameters should be checked for proper clearance. If any valve is shown to have flaws or excessive corrosion or improper clearances, the valve should be repaired or replaced. All other valves of that type should also be dismantled and inspected. ii. At least once a week during normal operation, main steam control and stop valves, reheat intercept and stop valves, and steam extraction non- return valves should be exercised by closing each valve and observing directly the valve motion as it moves smoothly to a fully closed position. iii. At least once a month during normal operation, each component of the electro-hydraulic governor system (which modulates control and intercept valves), as well as the primary and backup overspeed trip devices (both of which trip the main steam control and stop valves and the reheat intercept and stop valves), should be tested. The online test failure of any one of these subsystems mandates repair or replacement of failed components within 72 hours. Otherwise, the turbine should be isolated from the steam supply until repairs are completed. Refer to SRP Section 10.2 for additional information regarding inspection and testing of turbine generator components. D. The design, inspection, and operating conditions should provide assurance that the probability of turbine missile generation will not exceed those described in Table 3.5.1.3-1. 6. An applicant may propose to install barriers or to take credit for existing structures or features as barriers. Such a decision could be based on the applicant's deterministic judgment that a SSCs is particularly vulnerable to destruction or unacceptable damage in the event of a turbine failure. The applicant should include specific details in the safety analysis report (SAR) supporting the need for such protection. If an applicant proposes to design or evaluate barriers to reduce or eliminate turbine missile hazards to equipment, the barriers should meet the acceptance criteria