ML023610194
| ML023610194 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 12/13/2002 |
| From: | Hopkins L Constellation Nuclear |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NMP1L 1703 | |
| Download: ML023610194 (2) | |
Text
PO Box 63 Lycoming, New York 13093 Constellation Nuclear Nine Mile Point Nuclear Station December 13, 2002 A Member of the Constellation Energy Group NMP1L 1703 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555
SUBJECT:
Nine Mile Point Unit I Docket No. 50-220 License No. DPR-63 Special Report, Channel #12 Accident Monitoring Instrumentation Inoperable Due to Loss of Power Gentlemen:
In accordance with Action Statements 3.a and 4.a of Nine Mile Point Unit 1 Technical Specification Table 3.6.11-2, "Accident Monitoring Instrumentation Action Statements," Nine Mile Point Nuclear Station, LLC (NMPNS) is submitting the following Special Report concerning the inoperability of the Channel #12 Drywell Pressure Monitor, the Channel #12 Containment High Range Radiation Monitor, the Channel #12 Containment Hydrogen Monitor, and the Channel #12 Suppression Chamber Water Level indication.
Description of Event On December 2, 2002, at approximately 1647 hours0.0191 days <br />0.458 hours <br />0.00272 weeks <br />6.266835e-4 months <br />, Nine Mile Point Unit 1 experienced a loss of power to Reactor Protection System (RPS) bus #12. As a result, the Channel #12 Drywell Pressure Monitor, the Channel #12 Containment High Range Radiation Monitor, the Channel
- 12 Containment Hydrogen Monitor, and the Channel #12 Suppression Chamber Water Level indication were deenergized. This is energize-to-function instrumentation and thus was required to be declared inoperable. Power to RPS bus #12 is normally supplied by an uninterruptible power source, UPS 172. At approximately 1709 hours0.0198 days <br />0.475 hours <br />0.00283 weeks <br />6.502745e-4 months <br />, power was restored to RPS bus #12 from an alternate power source, Instrumentation and Controls bus #130A, and the Channel #12 accident monitoring instrumentation was returned to service.
On December 3, 2002, the Channel #12 accident monitoring instrumentation was again deenergized, between 1247 and 1248 hours0.0144 days <br />0.347 hours <br />0.00206 weeks <br />4.74864e-4 months <br />, to allow transferring RPS bus #12 back to its normal power source, UPS172.
Page 2 NMP1L 1703 For both of the instances described above, the Channel #11 Drywell Pressure Monitor, the Channel #11 Containment High Range Radiation Monitor, the Channel #11 Containment Hydrogen Monitor, and the Channel #11 Suppression Chamber Water Level indication were operable while the Channel #12 instrumentation was deenergized.
Cause of Event The loss of power to RPS bus #12 was due to the failure of protective relaying power supply PWRS-(PRC172)PS-1. The failed power supply has been sent to a vendor for failure analysis.
Corrective Actions
- 1.
The immediate corrective action was to restore power to RPS bus #12 from Instrumentation and Controls bus #130A.
- 2.
Power supply PWRS-(PRC172)PS-1 was replaced and on December 3, 2002, at approximately 1248 hours0.0144 days <br />0.347 hours <br />0.00206 weeks <br />4.74864e-4 months <br />, RPS bus #12 was returned to its normal power supply, UPS172.
Very truly yours, Lawrence A. Hopkins Plant General Manager LAH/DEV/jm xc:
Mr. H. J. Miller, Regional Administrator, Region I Mr. G. K. Hunegs, NRC Senior Resident Inspector