Document: NUREG-0800
Document ID: 7c10e1ce-ce1f-4c5c-8b11-53db665b85f4
Document Type: srp
Title: REACTOR COOLANT SYSTEM HIGH POINT VENTS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340642.pdf
Revision Date: 2023-06
Chapter: 5
Section ID: 5.4.12
CFR Part: 
CFR Title: 

Content:
Rs, block valves are not required in lines with safety valves used for venting. 3. Sufficient redundancy in the design shall be incorporated to minimize the probability of inadvertent actuation. Other methods to reduce the chances of inadvertent actuation, such as removing power or administrative controls, may be considered. 4. Since the reactor coolant system vent will be part of the reactor coolant system pressure boundary, all requirements for the reactor pressure boundary must be met. 5. The size of the vent line should be kept smaller than the size corresponding to the definition of a LOCA (10 CFR Part 50, Appendix A) to avoid unnecessary challenges to the ECCS. 6. Vent paths to the containment should discharge into areas that provide good mixing with containment air and are able to withstand steam, water, noncondensibles, and mixtures of the above. 7. The vent system shall be operable from the control room and provide positive valve position indication. Power shall be supplied from emergency buses. 8. It is important that the displays and controls added to the control room as a result of this requirement not increase the potential for operator error. A human-factor analysis should be performed taking into consideration: (a) the use of this information by an operator during both normal and abnormal plant conditions, (b) integration into emergency procedures, (c) integration into operator training, and 5.4-12-3 Rev. 0 - July 1981 (d) other alarms during emergency and need for prioritization of alarms. 9. Provisions to test for operability of the reactor coolant vent system should be a part of the design. Testing should be performed in accordance with subsection IWV of Section XI of the ASME Code for Category B valves. 10. The reactor coolant vent system (i.e., vent valves, block valves, position indication devices, cable terminations, and piping) shall be seismically and environmentally qualified in accordance with IEEE 344-1975 as supple- mented by Regulatory