ENS 49665
ENS Event | |
|---|---|
20:11 Dec 19, 2013 | |
| Title | Loss of Reactor Building Ventilation |
| Event Description | At 1511 [EST] on December 19, 2013, bus 10A404 (D channel 4 kv 1E vital bus) deenergized while transferring infeed breakers after degraded voltage testing. Reactor building ventilation fans tripped resulting in a loss of secondary containment negative pressure. Filtration Recirculation and Ventilation System (FRVS) was manually started and secondary containment negative pressure was restored at 1525 [EST].
Secondary containment pressure is stable with differential pressure negative. The technical specification requirement is to maintain secondary containment at a negative pressure for secondary containment integrity. Declaring secondary containment inoperable is reportable under 10CFR50.72(b)(3)(v)(C) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material. The standby reactor building ventilation fans did not automatically start and [the reason for that] is being investigated." The licensee notified the NRC Resident Inspector and will notify the Lower Alloways Creek township.
The licensee is retracting this report based on the following: Hope Creek Generating Station Unit 1, is retracting the 8-hour non-emergency notification made on December 19, 2013, at 1918 EST (EN 49665). The notification on December 19, 2013, reported that secondary containment was declared inoperable when reactor building ventilation system (RBVS) fans tripped resulting in the loss of secondary containment negative pressure. Subsequent engineering evaluation concluded that the safety function of secondary containment was not lost. The Hope Creek post-LOCA Exclusion Area Boundary, Low Population Zone, and Control Room dose calculation assumes that primary containment leakage is released directly to the environment with no credit for hold up or filtration for the first 375 seconds after the accident, i.e., the Hope Creek accident analysis does not assume that secondary containment is under vacuum at the start of an accident. In addition, the accident analysis relies upon the operation of the safety related Filtration Recirculation and Ventilation System (FRVS), which was fully operable. Upon receipt of an accident signal, FRVS would have automatically started and restored secondary containment negative pressure within the time limits of the design assumptions. The trip of the non-safety related RBVS and the failure of the stand-by RBVS fans to start did not result in an adverse impact on the dose consequence analysis. Although secondary containment was declared inoperable, the safety function was not lost and secondary containment was capable of performing its design function of minimizing any ground level release of radioactive material by providing a leak tight boundary so that FRVS may draw a vacuum In the Reactor Building and filter radioactive material at all times. The engineering evaluation is captured In the licensee's corrective action program. Based on the engineering evaluation, the condition reported in EN#49665 did not result in the loss of a safety function needed to control the release of radioactive material. This event report is being retracted. The NRC Resident Inspector has been briefed on the evaluation results and informed of this retraction. Notified R1DO (Powell). |
| Where | |
|---|---|
Hope Creek  New Jersey (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | |
| Time - Person (Reporting Time:+-0.88 h-0.0367 days <br />-0.00524 weeks <br />-0.00121 months <br />) | |
| Opened: | Michael Moore 19:18 Dec 19, 2013 |
| NRC Officer: | Dong Park |
| Last Updated: | Feb 14, 2014 |
| 49665 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 512742015-07-28T17:58:00028 July 2015 17:58:00
[Table view]10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Discovered One Inch Diameter Hole Between Reactor Building and Auxiliary Building ENS 496652013-12-19T20:11:00019 December 2013 20:11:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Loss of Reactor Building Ventilation ENS 450482009-05-08T12:17:0008 May 2009 12:17:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Primary Containment Isolation Valves Discovered Open ENS 409962004-08-29T23:28:00029 August 2004 23:28:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Alarm Indication of Inoperable Reactor Water Cleanup Supply Isolation Valve 2015-07-28T17:58:00 | |