ENS 48030
ENS Event | |
|---|---|
00:58 Apr 23, 2012 | |
| Title | Keowee Hydro Power Station Automatically Started Based on an Invalid Signal |
| Event Description | At 1958 [EDT] on 4/22/2012, Oconee emergency power (Keowee Hydro Station Units 1 and 2) automatically started based upon an invalid signal. In progress at the time was the Unit 3 Keowee Emergency Start Channel B Isolations section of the Unit 3 Engineered Safety Features Actuation System Replacement Modification procedure. A step in this procedure provided direction for a jumper to be connected between links B-13 and B-14. However, this jumper was placed between links A-13 and A-14, which caused the start of the Keowee units. During the period the jumpers were inadvertently installed, the Keowee units remained operable and available to supply emergency power to Units 1, 2, and/or 3. Both Keowee units were shutdown from the inadvertent emergency start actuation and the emergency start signal was reset per procedure at 0156 [EDT] hours on 4/23/2012.
The cause for the misplaced jumper was determined to be a human performance error by the technicians. As required per NUREG 1022, Rev.2 the following information is provided: (a) The specific train(s) and system(s) that were actuated: In this event, both Keowee Hydro Units 1 and 2 actuated because of the emergency start signal being generated by Channel A. (b) Whether each train actuation was complete or partial: The automatic actuation of the Keowee units was completed. (c) Whether or not the system started and functioned successfully: No problems or issues were identified with the performance of the Keowee Hydro Units in response to the emergency start. Therefore this condition is being reported for Oconee 1, 2, and 3 as an invalid actuation under 10 CFR 50.73 (a)(2)(iv)(A), which allows NRC notification via telephone per 10 CFR 50.73(a)(1). Corrective Actions: - Work was stopped on the Unit 3 Engineered Safety Features Actuation System Replacement Modification procedure; - Immediate investigation was conducted to determine the impact of the jumper activity as well as development of a recovery plan; and - The jumper was removed from links A-13 and A-14 and the Keowee units were shutdown. The NRC Resident Inspector was informed. |
| Where | |
|---|---|
Oconee  South Carolina (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation | |
| Time - Person (Reporting Time:+1287.03 h53.626 days <br />7.661 weeks <br />1.763 months <br />) | |
| Opened: | Corey Gray 16:00 Jun 15, 2012 |
| NRC Officer: | Pete Snyder |
| Last Updated: | Jun 15, 2012 |
| 48030 - NRC Website | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 480302012-04-23T00:58:00023 April 2012 00:58:00
[Table view]10 CFR 50.73(a)(1), Submit an LER Keowee Hydro Power Station Automatically Started Based on an Invalid Signal ENS 465442010-11-18T07:45:00018 November 2010 07:45:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Motor Driven Emergency Feedwater System ENS 451802009-05-19T20:09:00019 May 2009 20:09:00 10 CFR 50.73(a)(1), Submit an LER Invalid Feedwater System Actuation While Shutdown ENS 431462006-12-09T02:43:0009 December 2006 02:43:00 10 CFR 50.73(a)(1), Submit an LER Invalid Efw Actuations Due to an Issue in Sg Dryout Protection Circuit ENS 416492005-04-29T05:05:00029 April 2005 05:05:00 10 CFR 50.73(a)(1), Submit an LER Emergency Hydro Generators Auto Start - Unknown Cause ENS 406862004-03-20T19:59:00020 March 2004 19:59:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of the Motor Driven Emergency Feedwater Pumps 2012-04-23T00:58:00 | |