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| Entered date | Event description | |
|---|---|---|
| ENS 47094 | 26 July 2011 12:14:00 | This report is being made per paragraphs 50.73(a)(1) and 50.73(a)(2)(iv)(A) to address an actuation of Emergency Diesel Generator 'A' on June 3rd, 2011 while performing service water valve isolation signal testing. Emergency AC Electrical power system, including emergency diesel generators, is a system named in 50.73(a)(2)(iv)(B). During a refueling outage, testing was in progress to verify that service water isolation valves received the proper close signal during a safety injection. The test configuration required pulling control power fuses for the Bus 14 normal supply breaker to prevent operation and allow for manual relay actuation. Within seconds of pulling these fuses, the control room received a Bus 14 undervoltage annunciator, Emergency Diesel Generator 'A' started, and the generator output breaker closed onto Bus 14. Upon further investigation, the cause of this signal was identified as a degraded control relay that failed to mechanically latch and unexpectedly changed state when control power was removed. This resulted in an invalid undervoltage signal. Bus voltage remained within normal operating range. Given that the diesel generator was in unit mode of operation and was not fully synchronized with the normal bus supply, the diesel generator tripped shortly after starting due to a valid reverse power signal. A field verification and technical review was performed to ensure that this condition did not cause significant stress on the generator or engine. This start signal is considered an INVALID signal with respect to 50.73(a)(2)(iv)(A), however the system was not fully removed from service. The 'B' train was not affected by this event. The actuation was considered complete since all necessary components responded to the undervoltage signal as expected under the actual field conditions. The control relay would have remained in the desired position and performed its required function under design conditions with normal control power available. Therefore the degradation was not determined to have an impact on the safety function. The NRC Resident Inspector was notified. See related EN #46917. |
| ENS 46735 | 6 April 2011 21:20:00 | During walk downs for a planned site modification on April 6, 2011 at 1530 EDT, two degraded fire barrier seals were identified in the wall between the Auxiliary Building Basement and the Charging Pump Room. The wall is listed as an Appendix R wall between Fire Area (FA) ABBM and FA CHG. The wall separates redundant safe shutdown equipment. Two cylindrical six inch penetrations through the wall did not contain the required material to conform to a 3-hour fire rated barrier. This has been identified as a missing fire barrier such that the required degree of separation for redundant safe shutdown trains is lacking. A fire watch was established as a compensatory measure on 4/6/11. The discovery of this non-compliance is being reported as an unanalyzed condition as defined by 10 CFR 50.72(b)(3)(ii)(B). The NRC Resident Inspector has been notified of this event.
The purpose of this report is to retract the event discussed in Emergency Notification System report #46735 submitted on April 6th, 2011. The ENS notification reported an inadequate fire barrier penetration seal discovered on April 6th, 2011 when maintenance inspected the penetration in preparation for a modification. Initial investigation concluded that the fire barrier penetration seal between the Charging Pump room and Auxiliary Building Basement was inoperable because there was inadequate seal material to provide the required three hour barrier rating. It appeared that when looking in the penetration sleeve that a fire board from the opposite room was visible and no foam material was present. Subsequently, an engineering review of the penetration has been completed. The review determined that a minimum of 8 inches of foam is required to maintain a 3-hour rating. Engineering identified that the design also requires a fire board on each side of the foam. Upon measurement it was confirmed that at least 11 inches of the penetration was filled, with a fire board on each side. Based on these measurements, the fire barrier met design requirements and was operable. The individuals performing the initial investigation did not recognize the thickness of the wall. On April 7th, Maintenance proceeded to penetrate the fire barrier for the modification and it was confirmed that foam was behind the fire board. With a 24 inch thick wall, a large portion at the penetration sleeve can be void of material and still meet the 3 hour rating. As such, the April 6th, 2011 event is being retracted. The licensee notified the NRC Resident Inspector. Notified the R1DO (Caruso) |
| ENS 45510 | 19 November 2009 13:59:00 | The New York State Department of Environmental Conservation and other State and Local officials were notified today, November 19, 2009, that there had been a spill of low level radioactive material at an excavation site at the facility. Workers were conducting planned modification activities, replacing a section of piping, when sediment fell from the pipe to the ground and localized water at the excavation site. Samples of the localized water in the excavation after the sediment had fallen in exceeded the limit of the site procedure for notifying State and Local officials for a groundwater spill. No elevated levels have been detected in the nearest plant monitoring well. Therefore, we have no indications that there has been a release beyond the site from this source. Cleanup activities are currently in progress. The licensee notified the NRC Resident Inspector. The section of piping being replaced was between the plant storm drain system and the discharge canal. The radioactive material was identified as Cs-137 but was not quantified at the time of this report. |