05000348/FIN-2009004-03
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Finding | |
|---|---|
| Title | Load Sequencer Operability during EDG Surveillance Tests |
| Description | The NRC identified an issue of concern regarding the licensees failure to translate EDG system design into surveillance test procedures that rendered LOSP load sequencers inoperable during the performance of those tests. This issue of concern will be characterized as an unresolved item (URI) pending further inspection to determine what evaluations were completed by the licensee prior to scheduling and performing surveillance tests during modes of plant operation that required the EDGs and emergency load sequencers to be operable. On May 16, 2008, the licensee completed a review of an engineering judgement regarding the operation of the LOSP circuits with a diesel generator operating in the test mode. The engineering review was being performed in response to industry OE that identified issues where a diesel undergoing surveillance testing would not respond as desired during an LOSP event. As a result of that analysis, the licensee concluded that during a LOSP event while the diesel is in test mode and paralleled with offsite power (such that the LOSP relays actuate prior to the degraded grid or underfrequency relays), a LOSP load shed would occur and the diesel would remain running with its output breaker closed onto the bus. However, the automatic load sequencer would not start safety-related loads because the logic of LOSP circuit verifies that the diesel output breaker is open prior to allowing the load start sequence. For the condition identified above, the diesel would remain running and connected to the bus without emergency loads energized because the sequencer would not load the diesel. In response to the engineering analysis, the licensee entered CR 2008105195 into the CAP on May 24, 2008, and began declaring the EDGs inoperable while applying the 10 day completion time of condition B for TS 3.8.1, AC Sources Operating, when the diesels were paralleled with the offsite power source during surveillance tests. The NRC reviewed licensee actions in response to CR 2008105195 and the requirements of TS 3.8.1. The inspectors concluded that the licensee had identified a condition in which surveillance requirements for the load sequencer would not be satisfied in response to a design basis LOSP event. Therefore, the inspectors concluded that the 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> completion time for an inoperable automatic load sequencer as specified in condition G of TS 3.8.1 should be applied. The inspectors also concluded that previous performances of 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> EDG endurance surveillance runs exceeded the TS allowed outage time for an inoperable sequencer. As a result of the inspectors concerns regarding application of TS 3.8.1 condition G for an inoperable sequencer, the licensee deferred future performance of 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> EDG surveillance tests pending implementation of a design change in the EDG test circuit that would allow emergency loads to autostart. The inspectors determined that in order to appropriately evaluate and disposition this issue of concern, additional inspection would be required to better understand: (1) when the licensee began to schedule the performance of 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> EDG surveillance tests during plant modes of operation that required the emergency load sequencers to be operable, (2) what evaluation(s) for the schedule changes were performed by the licensee prior to the performance of those surveillance tests, and (3) whether or not the adequacy of those evaluations constituted a violation of regulatory requirements. The inspectors did not identify an immediate safety concern for this issue because: (1) the licensee had taken actions to modify surveillance test procedures to provide guidance for the operators to mitigate an LOSP condition during surveillance tests of the EDGs and (2) the licensee had deferred 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> EDG surveillance tests that would exceed the allowed outage time for an inoperable load sequencer pending implementation of a design change in the EDG test circuit that would allow emergency loads to auto-start in response to an LOSP event. This issue of concern was identified as URI 05000348,364/2009004-03, Load Sequencer Operability during EDG Surveillance Tests. |
| Site: | Farley  |
|---|---|
| Report | IR 05000348/2009004 Section 4OA2 |
| Date counted | Sep 30, 2009 (2009Q3) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71152 |
| Inspectors (proximate) | A Nielsen D Jones E Crowe G Kuzo H Gepford L Miller R Moore S Sandal S Shaefferb Desaib Sherbin C Even C Peabody D Jones J Eargle P Braxton R Moore R Patterson S Kobylarze Crowes Shaeffer W Rogers G Macdonald B Caballero S Sandal |
| INPO aspect | |
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Finding - Farley - IR 05000348/2009004 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Farley) @ 2009Q3
Self-Identified List (Farley)
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