Document: NUREG-0800
Document ID: ea7ce8f5-32bf-4d8c-a653-e964bff0ef48
Document Type: srp
Title: EMERGENCY CORE COOLING SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070448.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.3
CFR Part: 
CFR Title: 

Content:
. The reviewer should verify the ADS can satisfy performance requirements without taking credit for non-safety-related equipment or instrumentation, and accounting for normal air (or nitrogen) leakage through the valves (see item II.K.3.28 of Reference 34). For those BWR applicants which use a pneumatic supply for the ADS function, the capability and design of the pneumatic supply system is reviewed under SRP Section 9.3.1.94 d. The applicant’s evaluation of the ADS with respect to reactor vessel integrity limits is reviewed. If integrity limits could be exceeded during rapid cooldown, the applicant should evaluate alternate depressurization methods, other than full actuation of the ADS system, such as early depressurization with one or two relief valves (see item II.K.3.45 of Reference 34).95 11. The design of ECCS injection lines is reviewed to confirm that the isolation provisions at the interface with the reactor coolant system are adequate. The number and type of valves used to form the interface between low pressure portions of the ECCS and the reactor coolant system must provide adequate assurance that the ECCS will not be subjected to a pressure greater than its design pressure. This may be accomplished by any of the following provisions: a. One or more check valves in series with a normally closed motor-operated valve. The motor-operated valve is to be opened upon receipt of a safety injection signal once the reactor coolant pressure has decreased below the ECCS design pressure. b. Three check valves in series. DRAFT Rev. 3 - April 1996 6.3-14 c. Two check valves in series, provided that there are design provisions to permit periodic testing of the check valves for leaktightness and the testing is performed at least annually. 12. The reviewer should identify those portions of nonsafety-related systems which could have an adverse effect on ECCS and should ensure that modificationsdesign provisions are in place to correctprevent these situations. 96 13.