Document: NUREG-0800
Document ID: 5d88f9f1-c708-4a51-8593-a2aa484a15f3
Document Type: srp
Title: Revision 4 - March 2007
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0708/ML070850123.pdf
Revision Date: 2023-06
Chapter: 5
Section ID: 5
CFR Part: 
CFR Title: 

Content:
her only onsite or offsite power available. In demonstrating that the system can perform its function assuming a single failure, limited operator action outside of the control room would be considered acceptable if suitably justified. D. The system(s) shall be capable of bringing the reactor to a cold shutdown condition, with only offsite or onsite power available, within a reasonable period of time following shutdown, assuming the most limiting single failure. 2. RHR System Isolation Requirements The RHR system shall satisfy the following isolation requirements: A. The following shall be provided in the suction side of the RHR system to isolate it from the RCS: BTP 5-4-3 Revision 4 - March 2007 i. Isolation shall be provided by at least two power-operated valves in series. The valve positions shall be indicated in the control room. ii. The valves shall have independent diverse interlocks to prevent the valves from being opened unless the RCS pressure is below the RHR system design pressure. Failure of a power supply shall not cause any valve to change position. iii. The valves should have independent diverse interlocks to protect against one or both valves being open during an RCS increase above the design pressure of the RHR system, to the extent that such interlocks will not degrade high system reliability during shutdown operations (see Generic Letter 88-17). B. One of the following shall be provided on the discharge side of the RHR system to isolate it from the RCS: i. The valves, position indicators, and interlocks described in items 1(a) through 1(c) above. ii. One or more check valves in series with a normally closed power-operated valve. The power-operated valve position shall be indicated in the control room. If the RHR system discharge line is used for an ECCS function, the power-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. iii. Three check valves