Document: NUREG-0800
Document ID: 29fa664a-a42c-4ff0-8ae1-3798f7f23c23
Document Type: srp
Title: TURBINE MISSILES
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070373.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.5.1.3
CFR Part: 
CFR Title: 

Content:
ce 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. (c) 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 mechanical overspeed trip mechanism and backup electrical overspeed trip (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. Operating criteria appropriate to the orientation of the turbine should conform to those described in Table 3.5.1.3-1.27 7. 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 structure, system, or component 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 described in SRP Section 3.5.3. Additional design guidance is provided in Reference 4.28 DRAFT Rev. 3 - April 1996 3.5.1.3-10 Technical Rationale29 The technical rationale for application of these acceptance criteria to protecting safety-related structures, systems, and components