Document: NUREG-0800
Document ID: 7e0d3b3e-62c3-4492-ba89-6cebb4e82234
Document Type: srp
Title: SECONDARY CONTAINMENT FUNCTIONAL DESIGN
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340701.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.2.3
CFR Part: 
CFR Title: 

Content:
er than 100 volume percent per day, an exfiltration analysis should be provided. 5. The following leakage barriers in paths which do not terminate within the secondary containment should be considered potential bypass leakage paths around the leakage collection and filtration systems of the secondary containment: a. Isolation valves in piping which penetrates both the primary and secondary containment barriers. 6.2.3-10 Rev. 2 - July 1981 b. Seals ana gaskets on penetrations which pass through both the primary and secondary containment barriers. c. Welded joints on penetrations (e.g., guard pipes) which pass through both the primary and secondary containment barriers. 6. The total leakage rate for all potential bypass leakage paths, as identified i-n item 5 above, should be determined in a realistic manner, considering equipment design limitations and test sensitivities. This value should be used in calculating the offsite radiological consequences of postulated loss-of-coolant accidents and in setting technical specification limits with margin for bypass leakage. 7. Provisions should be made to permit preoperational and periodic leakage rate testing in a manner similar to the Type B or C tests of Appendix J to 10 CFR Part 50 for each bypass leakage path listed in item 5 above. An acceptable alternative for local leakage rate testing for welded joints would be to conduct a soap bubble test of the welds concurrently with the integrated (Type A) leakage test of the primary containment required by Appendix J. Any detectable leakage determined in this manner would require repair of the joint. 8. If air or water sealing systems or leakage control systems are pro- posed to process or eliminate leakage through valves, these systems should be designed, to the extent practical, using the guidelines for leakage control systems given in Regulatory Guide 1.96 (Ref. 4). 9. If a closed system is proposed as a leakage boundary to preclude bypass leakage, then the system should: a.