Document: NUREG-0800
Document ID: d2f0cc81-920c-4065-b74b-67114ba68b0e
Document Type: srp
Title: through 7.9 of the SAR. Where exceptions are taken to the guidance provided by regulatory guides, and
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0525/ML052500493.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7.2
CFR Part: 
CFR Title: 

Content:
planned manual actions, and to determine whether safety systems are operating properly. In addition, the instrumentation should also provide sufficient data for the operator to be able to evaluate the potential for core uncovery and gross breach of protective barriers, including the resultant release of radioactivity to the environment. NUREG-0737 provides additional guidance on conformance with this requirement. The evaluation of conformance with this requirement should be addressed in the review of Section 7.5 of the SAR. g. 50.34(f)(2)(xiv) [TMI Action Plan Item II.E.4.2] Containment Isolation Systems "Provide containment isolation systems that (A) ensure all non-essential systems are isolated automatically by the containment isolation system; (B) for each non-essential penetration (except instrument lines) have two isolation barriers in series; (C) do not result in reopening of the containment isolation valves on resetting of the isolation signal; (D) utilize a containment set point pressure for initiating containment isolation as low as is compatible with normal operation; and (E) include automatic closing on a high radiation signal for all systems that provide a path to the environs." Applicability — ESFAS — note that item (B) is not included in the scope of HICB review. Review Methods — The containment isolation functions of the ESFAS should be reviewed to confirm that the ESFAS automatically closes each isolation device on each nonessential penetration. Signal diversity should be provided for the containment isolation function. For plants with digital-computer based ESFAS, signal diversity can be confirmed by review of the licensee/applicant's defense-in-depth and diversity analysis. Reopening of isolation valves should be performed on a valve-by-valve basis, or on a line-by-line basis, provided that electrical independence and the single-failure criterion for the ESFAS functions continue to be satisfied. Ganged reopening of containment isolation