05000255/LER-2003-003, Loss of Shutdown Cooling and Emergency Diesel Generator Start
| ML031480570 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 05/20/2003 |
| From: | Cooper D Nuclear Management Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LER 03-003-00 | |
| Download: ML031480570 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(iv)(A), System Actuation |
| 2552003003R00 - NRC Website | |
text
Committed to Nuclear Excellence Palisades Nuclear Plant Operated by Nuclear Management Company, LLC May 20, 2003 10 CFR 50.73 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 PALISADES NUCLEAR PLANT DOCKET 50-255 LICENSE NO. DPR-20 LICENSEE EVENT REPORT 03-003, LOSS OF SHUTDOWN COOLING AND EMERGENCY DIESEL GENERATOR START Licensee Event Report (LER)03-003 is attached. The LER describes the loss of shutdown cooling and starting of emergency diesel generators that resulted from a loss of offsite power. This occurrence is reportable in accordance with 10 CFR 50.73(a)(2)(v)(B) as an event that prevented the fulfillment of the safety function of a system needed to remove residual heat, and in accordance with 10 CFR 50.73(a)(2)(iv)(A), as an event that resulted in automatic actuation of the emergency ac electrical power system.
SUMMARY OF COMMITMENTS This letter contains no new commitments and no revisions to existing commitments.
Do g E. Cooper Site Vice-President, Palisades CC Regional Administrator, USNRC, Region IlIl Project Manager, USNRC, NRR NRC Resident Inspector-Palisades Attachment 27780 Blue Star Memorial Highway
- Covert, Ml 49043 Telephone: 616.764.2000 T6-aaeD',.
Abstract
On March 25, 2003, at 1116 hours0.0129 days <br />0.31 hours <br />0.00185 weeks <br />4.24638e-4 months <br />, with the plant in Mode 6, a loss of offsite power occurred while installing a signpost. The signpost penetrated a buried conduit, damaging a control power cable associated with both offsite power feeds. As a result, the safety-related and non-safety related buses de-energized, which caused a loss of shutdown cooling flow. The emergency diesel generators started and loaded safety-related buses, as expected. An Alert was declared at 1126 hours0.013 days <br />0.313 hours <br />0.00186 weeks <br />4.28443e-4 months <br />. Shutdown cooling flow through the core was restored in approximately 20 minutes. The Alert was downgraded to an Unusual Event at 1231 hours0.0142 days <br />0.342 hours <br />0.00204 weeks <br />4.683955e-4 months <br />. The Unusual Event was exited on March 27, 2003, at 1737 hours0.0201 days <br />0.483 hours <br />0.00287 weeks <br />6.609285e-4 months <br />, when offsite power was fully restored.
This occurrence is reportable in accordance with 10 CFR 50.73(a)(2)(v)(B) as an event that prevented the fulfillment of the safety function of a system needed to remove residual heat, and in accordance with 10 CFR 50.73(a)(2)(iv)(A), as an event that resulted in automatic actuation of the emergency AC electrical power system.
NRC FORM 366 (7-2001)
(If more space is required, use additional copies of (If more space is required, use additional copies of NRC Form 366A)
CAUSE OF THE EVENT
There was no written process for controlling excavating/trenching/piercing the ground. Additionally, NMC missed an opportunity in May 2002 to identify the lack of procedural controls when an inadequate evaluation was performed for a previous event.
CORRECTIVE ACTIONS
A plant policy was issued prohibiting all digging and landscaping activities without appropriate approval and oversight.
The damaged cable was repaired, and the control circuits for one of the two offsite power feeds were relocated to a separate cable.
A procedure is being written to control excavating/trenching/piercing activities.
SAFETY SIGNIFICANCE
All safety systems functioned as designed. Primary coolant system temperature increased from approximately 92°F to 104°F. The average hourly heat-up rate limit specified in Technical Specification 3.4.3 was not exceeded. Fuel integrity was not challenged.
PREVIOUS SIMILAR EVENTS
Palisades has had several instances where equipment or cabling was damaged as a result of excavation/digging/trenching activities; however, none have caused a loss of offsite power.