Document: NUREG-0800
Document ID: 164d26ee-2125-481e-9fae-fb7b05365716
Document Type: srp
Title: RESIDUAL HEAT REMOVAL (RHR) SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340635.pdf
Revision Date: 2023-06
Chapter: 5
Section ID: 5.4.7
CFR Part: 
CFR Title: 

Content:
formation. A failure modes and effects analysis (or similar system safety analysis) provided in the SAR is used to determine conformance to the single failure criterion. 2. Using the comparison tables of SAR Section 1.3, the RHR system is compared to designs and capacities of such systems in similar plants to see that there are no unexplained departures from previously reviewed plants. Where possible, comparisons should be made with actual performance data from similar systems in operating plants. 3. From the system description and P&IDs, the reviewer determines that the isolation requirements of Branch Technical Position RSB 5-1 (Ref. 5) are satisfied. 4. The reviewer determines that the RHR system design has provisions to prevent damage to the RHR pumps in accordance with Branch Technical Position RSB 5-1 (Ref. 5). The reviewer checks the isolation valves in the suction line for potential closure, NPSH requirements, pump runout, and potential loss of miniflow line during pump testing. If operator action is required to protect the pumps, the reviewer evaluates the instrumentation required to alert the operator and the adequacy of the time frame for operator action. 5.4.7-6 Rev. 3 - April 1984 5. The RHR systems is reviewed to evaluate the adequacy of design features that have been provided to prevent damaging water (steam) hammer due to such mechanisms as voided discharge lines, water entrainment in steam lines and steam bubble collapse. For systems with a water supply above the discharge lines, voided lines are prevented by proper vent location and filling and venting procedures. The vents should be located for ease of operation and testing on a periodic basis. If the normal alignment of suction valves is to a source below the highest level of the pump discharge lines (e.g., the suppression pool for RHR systems of BWRs) back leakage through the pump discharge check valves will result in line voiding. Proper vent location and filling and venting procedures are