Document: NUREG-0800
Document ID: 68c52f40-6536-4c97-a8ab-72ea2a8c1c8c
Document Type: srp
Title: TURBINE BYPASS SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070595.pdf
Revision Date: 2023-06
Chapter: 10
Section ID: 10.4.4
CFR Part: 
CFR Title: 

Content:
er, reliable power sources must be available for control and isolation valves so that a control operator can establish the flow path assuming a single active failure. B. TBS lines and other components utilized as an MSIV leakage path to the condenser are assigned a quality group classification in accordance with the criteria of SRP Section 3.2.2, Appendix A.24 Technical Rationale: The technical rationale for application of these acceptance criteria to the TBS is discussed in the following paragraphs:25 A. GDC 4 requires that structures, systems, and components important to safety be designed to meet environmental conditions associated with normal operation, maintenance, testing, and postulated accident conditions. However, dynamic effects associated with postulated pipe ruptures in nuclear power plants may be excluded from the design basis when analyses reviewed and approved by the Commission demonstrate that the probability of a rupture in the fluid system piping is extremely low under conditions consistent with the design basis for the piping. Although the turbine bypass system is not classified as a system important to safety, GDC 4 applies to this SRP section because a failure of the TBS or one of its components could have an adverse impact on a structure, system, or component important to safety. Meeting the requirements of this criterion provides a level of assurance that structures, systems, and components important to safety will not be adversely affected by a failure of the turbine bypass system.26 B. GDC 34 requires that the applicant provide a system to remove residual heat, and it establishes specific requirements related to performance, redundancy, and reliability. Although the TBS is not the residual heat removal system specified in GDC 34, it can perform that function. GDC 34 applies to this SRP section because using the TBS during normal plant shutdown reduces demands on systems important to safety. 10.4.4-5 DRAFT Rev. 3 - April 1996 Meeting the