PNO-IV-98-021A, on 980526,update to Loss of Offsite Power Made.Components Have Been Replaced & Sys Functioning Properly.Correction Should Be Made to Info in Original Pn. Nonvital Buses 1A1 & 1A2 Continuously Energized
| ML20247P373 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 05/26/1998 |
| From: | Johnson W, Webb Patricia Walker NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| References | |
| PNO-IV-98-021A, PNO-IV-98-21A, NUDOCS 9805270428 | |
| Download: ML20247P373 (1) | |
.
l i.
4 4 May 26,'1998 PREllM!hARY NOTIFICATION OF EVENT OR UNUSUAL-OCCURRENCE PNO-IV-98-021A l
This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or i
public interest significance. The information is as initially received without verification or
. evaluation, and is basically all that is known by Region IV staff in Arlington, Texas on this date.
Facility kicensee Emeroency Class:ficatio.a.
Orqaha Public Power District Notification of Unusual Event Ft Calhoun 1 Alert Fort Calhoun, Nebraska Site Area Eme;gency Dockets: 50-285 General Emergency X Not Applicable
Subject:
UPDATE TO LOSS OF OFFSITE POWER This is to update the information provided on May 21,1998. The licensee has concluded that the cause of the loss of 161 kV offsite power to vital Buses 1A3 and 1A4 was an actuation of the fire protection deluge system for Transformer T1 A-3 which subsequently caused arcs between Phase B and ground and between Phases B and C of Transformer T1A-3. The fire protection de!uge valve actuated as a result of mechanical failure of two smaller valves associated with the main deluge valve. These components have been replaced, and the system is functioning properly.
Buses 1 A3 and 1A4 were transferred to 161 kV power via Transformers T1 A-3 and T1A-4 on May 24, which placed the plant in a normal electrical configuration. The plant is currently in Mode 3 at approximately 520 degrees F,2100 psig, and is being raised to normal operating temperature and pressure in preparation for plant startup which is scheduled for May 27.
A correction should be made to the information in the original PN. The loss of 161 kV power did not result in a complete loss of offsite p>wer to the facility. Nonvital Buses 1 A1 and 1A2 were continuously energized throughout the event via 345 kV offsite power.
This information has been discussed with the licensee and was current as of 10:20 a.m. on May 26,1998.
The states of Nebraska and lowa have been informed.
Contact:
W. D. Johnson (817)860-8148 W. C. Walker (402)426-9611 9805270428 980526 PDR I4eE PNO-IV-98-021A PDR g
f
\\* c~, \\
r/0101