ENS 46165
ENS Event | |
|---|---|
17:30 Aug 9, 2010 | |
| Title | 4160 Vac Control and Transfer Breaker Switch Defect |
| Event Description | On August 9, 2010 at 12:30 CDT, Nebraska Public Power District (NPPD) completed a reportability determination which concluded that certain General Electric - Hitachi (GEH) Type SB-1 Control and Transfer Switches, contained a defect that would have prevented the remote and/or automatic opening and closing of safety related 4160 VAC breakers at Cooper Nuclear Station (CNS), had the switches been installed as received. NPPD has concluded this condition is reportable per 10 CFR Part 21.
Specifically, GEH supplied 23 Type SB-1 Control and Transfer Switches under GEH part number Q16SB1EB4G75SSS1C142 to CNS. 14 of the 23 switches exhibited a failure to maintain the established contact logic when implementing the logic feature of these switches. This condition was discovered during pre-installation testing in support of a station modification of 4160 VAC breaker control. The defect would have prevented the remote and/or automatic opening and closing of the essential affected 4160 VAC breakers. This would have prevented the transfer of the essential 4160 VAC switchgear from the normal station service transformer to either source of offsite power or the emergency diesel generators and the sequential loading of emergency core cooling system pumps in response to a design basis accident LOCA. All of the switches have been returned to GEH, and none were installed in the station. Therefore, the condition is not reportable under 10 CFR 50.72 or 50.73. These switches were designed and supplied by GEH as a safety related part, specifically for CNS. NPPD is unaware as to if this specific switch design has been supplied to any other licensee. The condition is being reported under 10 CFR 21.21(d)(3)(i). The Responsible [NPPD] Corporate Officer has been notified of this condition per 10 CFR 21.21(d)(3)(i) on August 9, 2010 at 15:45 CDT- Pursuant to 10 CFR 21.21(d)(3)(ii) written notification is due to the NRC within 30 days of this notification. The licensee will notify the NRC Resident Inspector. |
| Where | |
|---|---|
| Cooper Nebraska (NRC Region 4) | |
| Reporting | |
| 10 CFR 21.21 | |
| Time - Person (Reporting Time:+20.22 h0.843 days <br />0.12 weeks <br />0.0277 months <br />) | |
| Opened: | David Nelson Madsen 13:43 Aug 10, 2010 |
| NRC Officer: | Mark Abramovitz |
| Last Updated: | Aug 10, 2010 |
| 46165 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 461652010-08-09T17:30:0009 August 2010 17:30:00
[Table view]10 CFR 21.21 4160 Vac Control and Transfer Breaker Switch Defect ENS 453342009-09-08T14:30:0008 September 2009 14:30:00 10 CFR 21.21 Defect Found in Bussmann Fuses ENS 446342008-11-06T14:56:0006 November 2008 14:56:00 10 CFR 21.21 Defect Found in Bussman Fuses 2010-08-09T17:30:00 | |