Document: NUREG-0800
Document ID: eb937958-fe7c-410a-91e3-63f04734878a
Document Type: srp
Title: MAIN STEAM ISOLATION VALVE LEAKAGE CONTROL SYSTEM (BMR)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052350465.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.7
CFR Part: 
CFR Title: 

Content:
udgment, the results of failure modes and effects analyses, and the results of reviews performed under other SRP sections indicated in subsection I of this SRP section to determine that the failure of nonessential portions of the system or of other systems not designed to seismic Category I and located close to essen- tial portions of the system, or of nonseismic Category I structures located close to essential portions of the system, will not preclude operation of the essential portions of the MSIVLCS. Reference to SAR sections describing site features, the general arrangement and layout drawings, and the tabula- tion of seismic design classifications for systems and structures will be necessary. Statements in the SAR that the above conditions are met are acceptable. 3. If the leakage control system is one using a fluid sealing medium: a. The system design is reviewed to determine that the quantity of sealing fluid needed for an effective seal of the valves has been provided. Independent analyses, using the pump performance curves in the SAR, are made to assure that the design and the location of the pump and components are such as to maintain the appropriate net positive suction head (NPSH) requirements and provide a continuous supply of sealing fluid during the full course of an accident. b. The system design is reviewed to determine that effects resulting from the sealing fluid, such as thermal stresses, pressures associated with flashing, thermal deformations, and other effects will not effect the structural integrity of the steam lines or the main steam isolation valves, or lead to excessive leakage of the valves. This portion of the review is done on a case-by-case basis. The ASB also accepts the system design if a statement in the SAR commits to performing calculations or functional testing to demonstrate that the above conditions are met. 4. The MSIVLCS is reviewed to verify that instrumentation, controls, and inter- locks designed to standards appropriate