Surveillance Requirement 3.8.4.7 of the Callaway TS requires that every 18 months the licensee, verify that the battery capacity is adequate to supply, and maintain in
OPERABLE status, the required emergency loads for the design duty cycle when subjected to a battery service test. The service test to which the NK11 and NK14 safety related batteries are subjected at the required 18-month frequency was described in Callaway test procedures MSE-NK-QB011 and MSE-NK-QB014, respectively. The teams review of these procedures determined that the service test loading requirements and durations were included in Section 3.1 of the procedures, as part of the acceptance criteria for battery service test (duty cycle) and that these requirements corresponded to those specified in Table 8.3-2 of the
FSAR, 125 V
DC Class
IE Battery Loading Cycle (Amperes Required per Time Interval per Battery after Loss of
AC Power) Subsystems 1 and 4. The latest revision of Table 8.3-2 was dated March 2003. The team also observed that the 200-minute duration for the duty cycle, contained in the
FSAR table and the test procedure, was not consistent with another section of the
FSAR. In fact, in Table 8.3A-1, as a result of their station blackout coping analysis, the licensee concluded that Callaway was a four-hour or a 240-minute plant. This statement implies that the battery must be proven to be capable of providing adequate voltage to the station blackout loads for the entire coping duration, 240 minutes, and have sufficient capacity to allow restoration of the normal
AC power sources at the end of the 240- minute coping period. The licensee recognized the need to demonstrate such capability and in Note 2 of Table 8.3-2 stated that The 200 minute duty cycle is the design load cycle for the batteries. The batteries have been analyzed for a 240 minute loading cycle to support the Station Blackout coping analysis. The teams review of the
battery sizing calculation determined that the licensee did evaluate the capability of the selected batteries to support the 240 minute loading cycle during the station blackout, albeit the licensee made no distinction between LOCA/LOOP and
SBO loads. The importance of the service (duty cycle) test is to confirm that, given the plant specific duty cycle loading, the battery is capable of supplying adequate voltage to the loads for the duration of the service life of the battery and to detect degradation of the system as the battery approaches the end of its service life. The team discussed their concern with the licensee who simply indicated that the 200 minute duty cycle in the test enveloped the 240 minute loading cycle calculated in NK-05. This item is unresolved pending further review by the NRC of the license requirements under the
SBO rule and the licensees revision of
battery sizing calculation, NK-05.
URI 05000483/2008008-04, Adequacy of the NK11 Battery Service Test
