PNO-IV-97-021, on 970421,extraction Steam Line to Feedwater Heater Ruptured in Fort Calhoun Station Turbine Bldg. Licensee Restricted Access to Turbine Bldg & Implemented Respiratory Protection Requirements for Access
| ML20137Y027 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 04/22/1997 |
| From: | Johnson W, Webb Patricia Walker NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| References | |
| PNO-IV-97-021, PNO-IV-97-21, NUDOCS 9704220296 | |
| Download: ML20137Y027 (1) | |
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l April 22,1997 I
PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNO-IV-97-021 4
This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or 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 Licensee Emeraency Classification Omaha Public Power District X Notification of Unusual Event Ft Calhoun 1 Alert Fort Calhoun, Nebraska Site Area Emergency Dockets: 50-285 General Emergency Not Applicable
Subject:
EXTRACTION STEAM LINE BREAK At approximately 8:23 p.m. (CDT), a 12-inch extraction steam line to a feedwater heater j
ruptured in the Fort Calhoun Station turbine building. When operators heard a loud noise 1
from the turbine building, the reactor was manually tripped and was stabilized in Mode 3.
All safety systems responded normally. A Notification of Unusual Event was declared at 8:45 p.m. to increase awareness and enhance staff augmentation. It was subsequently terminated at 11:45 p.m. (CDT) following plant stabilization.
The rupture (estimated by the licensee to be approximately 3 feet long) occurred at the outer edge of a large radius bend in the extraction steam line. No personnel were injured, but significant steam impingement damage to balance-of-plant Motor Control Centers 4C3 and 4C5 occurred. The fire suppression system actuated in the area and was subsequently isolated. Intermittent electrical system grounds occurred during the event.
. Insulation, containing esbestos, was blown throughout the turbine building. The licensee has restricted access to the turbine building and has implemented respiratory protection requirements for access.
The licensee is placing the plant in cold shutdown to perform necessary repairs to the steam piping, inspect similar extraction steam lines, and repair or replace the damaged motor control centers. In addition, the licensee plans to perform other forced outage work, including replacement of the seal package on Reactor Coolant Pump 3C. The licensee has not yet determined the outage duration.
The states of Nebraska and lowa have been informed.
The licensee plans to issue a press release.
Region IV received notification of this occurrence by telephone from the resident inspector at approximately 9:15 p.m. (CDT) on April 21,1997. Region IV has informed the EDO's office, NRR, and Public Affairs.
This information has been discussed with the licensee and is current as of 9:15 a.m.
(CDT).
Contact:
Wayne Walker (402)426-9611; William Johnson (817)860-8148
%x 9704220296 970422 PDR I&E PNO-IV-97-021 PDR
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