On February 15, 2012, with Unit 1 shutdown for an
RFO, it was identified that two doors to the Unit 1 TDRFP rooms (doors 203 and 207) were propped open with cables and hoses. Corrective action program documents estimated that the doors were propped open for about
12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. Doors 203 and 207 were required to remain shut to act as
HELB barriers while the floor plugs in the TDRFP rooms were removed, since the open plugs allowed the rooms to communicate with the Unit 1 auxiliary building. It is yet unknown as to the full extent of
SSCs that were at risk within the auxiliary building as a result of the defeated hazard barriers. The lack of protection from a postulated Unit 2-generated
HELB had the potential to adversely affect the operability/functionality of any
SSCs in the area not environmentally qualified for the harsh conditions that a
HELB might produce. In response to the inspectors questions about the specific
SSCs that could have been affected, the licensee sought assistance from an outside contractor to perform an analysis of the postulated
HELB effects. The results of this analysis will be required for the inspectors to complete their assessment of this issue. Therefore, an Unresolved Item is opened pending further review by the NRC staff of the licensees analysis. (
URI 05000373/2012002-01 and
05000374/2012002-01), Potential Impact on Operability of Safety-Related Components Due to Defeated High Energy Line Break Barriers
