Document: NUREG-0800
Document ID: fd06ef1f-75ea-4f29-9779-8714e92f3050
Document Type: srp
Title: MAIN STEAM ISOLATION VALVE LEAKAGE CONTROL SYSTEM (BWR)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070451.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.7
CFR Part: 
CFR Title: 

Content:
REVIEW RESPONSIBILITIES Primary - Auxiliary Systems BranchPlant Systems Branch (ASBSPLB)1 Secondary - None I. AREAS OF REVIEW Direct cycle boiling water reactor (BWR) plants have redundant quick-acting isolation valves on each main steam line from the reactor to the turbine. In the event of a loss-of-coolant accident (LOCA), any leakage of contaminated steam through these valves is controlled by a leakage control system. The leakage control system must satisfy the requirements of General Design Criteria 2, 4, and 54. As an alternative, the applicant may use a passive method of controlling offsite consequences resulting from leakage past steam line isolation valves in the event of a LOCA by taking credit for fission product plateout and holdup in the large volume and surface area of the main steam piping, main steam drain lines, turbine bypass line, turbine, and main condenser subject to complying with additional requirements for these items.2 The review of the main steam isolation valve leakage control system (MSIVLCS) covers the entire leakage control system, including the source of the sealing medium, if any, and pumps, valves, and piping to the points of connection or interface with the main steam supply system. Emphasis is placed on the components of the leakage control system that are required to remain functional following a design basis LOCA. 3 DRAFT Rev. 3 - April 1996 6.7-2 1. ASB SPLB reviews the design of the MSIVLCS and essential subsystems to 4 assureensure their ability to function following a postulated LOCA, including the loss of 5 offsite power. The system is reviewed to determine that: a. A malfunction or failure of an active component of the system, or loss of the source of sealing fluid, if any, will not impair the functional performance of the system. b. The failure of nonseismic Category I equipment or components will not have an adverse effect on the ability of the system or components to function. c. The capability of the system to perform