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The licensee identified a finding of very low safety significance (Green) and associated NCV of 10 CFR Part 50, Appendix R, Section III.G.2.a, Fire Protection of Safe Shutdown Capability. Specifically, the licensee identified that the structural steel located in the plant administrative building (PAB) basement supporting the cable spreading room (CSR) floor did not have a 3hour fire rating as required by 10 CFR 50, Appendix R, Section III.G.2.a. Title 10 CFR 50, Appendix R, Section III.G.2.a, requires, in part, that where separation of cables and equipment and associated non-safety circuits of redundant trains by a fire barrier having a 3hour rating is provided, structural steel forming a part of or supporting such fire barriers shall be protected to provide fire resistance equivalent to that required of the barrier. Contrary to the above, since 1982, the licensee failed to protect the structural steel supporting the fire barrier between the cable spreading room and fire area IV. This failure was identified by the licensee on August 4, 2016 during an Appendix R self-assessment and addressed in CAP 1530637. The licensee issued LER 201600201 in response to this Appendix R non-compliance and implemented the immediate corrective action (compensatory measure) of an hourly fire watch in the affected fire area. The licensee conducted an exposed steel fire simulation and evaluation to understand the performance of the unprotected steel in the event of a fire in the PAB. The inspectors reviewed the licensees simulation and evaluation. This finding was determined to be more-than minor because the performance deficiency was associated with the protection against external factors (fire) attribute of the Mitigating Systems Cornerstone and adversely affected its objective to ensure the availability and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, the structural steel supports the fire barrier between the CSR and the PAB basement and a failure to protect the structural steel from fire damage would degrade the fire barrier separating the CSR and PAB. This could result in a fire in the PAB spreading to the CSR due to the degraded fire barrier resulting in an evacuation of the control room. The only means for operators to shutdown the reactor using the ASDS panel would require travel through the PAB fire area where a fire event is occurring. Therefore, this finding impacted the safe shutdown capability of the plant. After review of the licensees exposed steel fire simulation and evaluation, the finding was determined to be of very low safety significance (Green) because the licensee demonstrated that the unprotected structural steel would provide at least one hour of fire endurance rating under a fire event in the PAB.
|Report||IR 05000263/2017004 Section 4OA7|
|Date counted||Dec 31, 2017 (2017Q4)|
|Inspectors (proximate)||P Zurawski|
|Violation of:||10 CFR 50 Appendix R, Appendix R to Part 50-Fire Protection Program for Nuclear Power Facilities Operating Prior to January 1, 1979|
Finding List (Monticello) @ 2017Q4
Self-Identified List (Monticello)