Morning Report for June 6, 2000
Headquarters Daily Report JUNE 06, 2000 *************************************************************************** REPORT NEGATIVE NO INPUT ATTACHED INPUT RECEIVED RECEIVED HEADQUARTERS X REGION I X REGION II X REGION III X REGION IV X PRIORITY ATTENTION REQUIRED MORNING REPORT - HEADQUARTERS JUNE 6, 2000 Licensee/Facility: Notification: Carolina Power & Light Co. MR Number: H-00-0034 Brunswick 1 Date: 06/06/00 Southport,North Carolina Dockets: 50-325 BWR/GE-4 Subject: Potential for Chemical Fire Suppressant Release to Impact Operability of Emergency Diesel Generators Reportable Event Number: 36750 Discussion: On 3/3/00, Carolina Power & Light, the Brunswick licensee, declared an Unusual Event (UE) because of a loss of offsite power (LOOP) to both 4160-volt emergency electrical buses at Brunswick Unit 1 (EN #36750). Unit 1 was in a refueling outage with relay testing ongoing in the plant switchyard, when a switch positioning error resulted in a LOOP. All four emergency diesel generators (EDGs) started as designed, with DG1 and DG2 supplying their respective safety-related buses. DG3 and DG4 did not pick up loads to their respective buses because those buses did not lose power. About two hours after the LOOP, DG2 tripped and the diesel building fire protection system actuated when the excitation system power potential transformer (PPT) for DG2 shorted out. A chemical fire suppressant (Halon 1301) was released into the basement of the diesel building where the PPT was located. The halon discharge into the basement created sufficient pressure to unexpectedly open a tornado damper between the basement and the rest of the building. Halon escaped into the upper portion of the building, where DG1, DG3, and DG4 drew in an air/halon mixture through their individual air intakes. The release of halon into the upper portion of the diesel generator building raised two concerns regarding EDG operability. The halon and combustion interaction caused the lube oil on the three running EDGs to become contaminated with halon in excess of the oil vendor-approved limit of 50 parts per million (ppm). During the combustion process it is normal for some of the combustion chamber exhaust gases to interact with the crankcase oil because of leakage of the gases past the piston rings. The concern with halon contaminating the oil is an accelerated degradation of the oil and increased corrosion rates. The halon reduces the alkalinity of the oil which may increase the formation of acids that could cause corrosion of the engine components. Oil samples taken from DG3 and DG4 indicated halon levels of 53 ppm. Oil samples from DG1 indicated halon levels of 200 ppm. The licensee determined that halon contamination of the oil was not an immediate operability concern, but it could result in premature degradation of engine components. The licensee has set 20 ppm as an administrative limit for halon in the lube oil. The licensee will change the oil in each EDG during the next scheduled outage window. The second concern with EDG operability is the effect of the air/halon mixture on the ability of the EDGs to operate at maximum load capacity. Subsequent to the event, the licensee performed testing to determine if the air/halon mixture would affect the EDGs. The licensee conservatively HEADQUARTERS MORNING REPORT PAGE 2 JUNE 6, 2000 MR Number: H-00-0034 (cont.) assumed that the full 6 percent halon atmosphere released into the basement would be ingested by one of the three operating EDGs. The licensee concluded that there was more than adequate margin in the volume of available combustion air and the release of the halon would have no effect on EDG operability. Contact: Eugene Guthrie, RII (910)457-9531 David Skeen, NRR (301)415-1174 _
Page Last Reviewed/Updated Wednesday, March 24, 2021
Page Last Reviewed/Updated Wednesday, March 24, 2021