Fire Areas 2 and 14 contained redundant trains of systems, equipment, and cables necessary to accomplish post-fire SSD conditions. In the event of an unmitigated fire in either of these areas the licensees
SSA credited the use of an alternative shutdown capability designated as the
SSS. The
SSS was comprised of existing plant safety related systems as well as certain dedicated equipment that would be used in the event of a fire which required shutdown of the unit from the SSF.
Section III.L.3 of Appendix R to
10 CFR 50 requires, in part, that the alternative shutdown capability be physically and electrically independent of the fire area under evaluation. The team assessed the adequacy of electrical independence provided for the alternative shutdown capability (i.e.,
SSS) in the event of a fire in Fire Area 2 or Fire Area 14. The
SSS relied on the use of the turbine driven CA pump to accomplish the
decay heat removal shutdown function. Hence, the routing of power and control cables associated with a sample of components required to assure the operability of the turbine driven CA pump was reviewed. This review determined that certain cables associated with the turbine driven CA pump suction valve (Valve 1CA7AC) could be subject to damage as a result of a fire in either of these areas. Specific cables included: 1*CA516, 1*CA517, 1*CA519, 1*CA761, and 1*CA763. Fire damage to these cables had the potential to cause valve 1CA7AC to fail closed. Should this occur, the turbine driven CA pump would be damaged in a short period of time due to a loss of pump suction. Although this scenario had been identified by the licensee, operator actions credited in the
SSA to mitigate this event were not appropriate. Specifically, the team determined that the licensees credited recovery actions in the
SSA could not be completed in a sufficiently timely manner necessary to prevent pump damage. The operator actions in the
SSA had not been translated to appropriate operations procedures (e.g., AP/1/A/5500/24). Additionally, local manual actions to reopen valve 1CA7AC would require an operator to traverse Fire Area 2. This issue will be tracked as Unresolved Item (
URI) 50-369, 370/00-09-01: Potential for Loss of
Auxiliary Feedwater Flow for an Appendix R Fire in Fire Areas 2 or 14. The team noted that certain byproduct associated circuits issues (e.g., fire-induced spurious operations or mal-operations) are the subject of an ongoing, voluntary industry initiative. This
URI is considered an example of a \"byproduct\" associated circuits issue and will be tracked as a
URI pending generic resolution of the related issue. This issue was entered in the licensees corrective action program as Problem Investigation Process (
PIP) No. M-00-04480.
