ML15205A371
| ML15205A371 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 07/24/2015 |
| From: | David Proulx, Uselding L NRC Region 4 |
| To: | |
| D. Proulx | |
| References | |
| PN-IV-15-001 | |
| Download: ML15205A371 (1) | |
Text
July 24, 2015 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE - PNO-IV-15-001 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 the Region IV, Arlington, Texas staff on this date.
Facility Union Electric Company Callaway Plant P.O. Box 620 Fulton, MO 65251 Docket: 50-483 License No. NPF-30 Licensee Emergency Classification
__Notification of Unusual Event
__Alert
__Site Area Emergency
__General Emergency X Not Applicable
SUBJECT:
CALLAWAY PLANT TECHNICAL SPECIFICATION SHUTDOWN DUE TO REACTOR COOLANT SYSTEM LEAKAGE DESCRIPTION:
On July 23, 2015, at 1:15 a.m. (all times CDT), Callaway Plant operators commenced a reactor shutdown from 100 percent power in response to reactor coolant system leakage in excess of the Technical Specification (TS) 3.4.13 limit of 1 gallon per minute.
On July 22, 2015 at 9:09 p.m. control room operators received alarms indicating elevated containment radiation, humidity, temperature, and sump levels. At 9:39 p.m. operators diagnosed unidentified reactor coolant system leakage of approximately 1.6 gallons per minute.
The resident inspectors responded to the site to monitor the licensees response to the event.
On July 23, 2015, at 6:00 a.m., the plant reached Mode 3 (Hot Shutdown). The operators commenced a plant cool down at 12:10 p.m. During the cool down, the B main feed pump was tripped following an indication of a loss of flow. Operators manually initiated auxiliary feedwater to maintain steam generator levels. At 5:02 p.m. the licensee entered the containment building and determined the source of the leak to be from a gasket on a blind flange on a 3/4 inch drain valve off of the auxiliary pressurizer spray line. The licensee has repaired the gasket leak while in Mode 3 and is conducting other work prior to restart.
Region IV received notification of this occurrence by a phone call from the resident inspectors at 10:53 p.m. on July 22, 2015. The state of Missouri has been notified.
The information presented herein has been discussed with the licensee and is current as of 2:00 p.m. CDT, July 24, 2015.
This preliminary notification is issued for information only and no further action by the staff is anticipated.
ADAMS ACCESSION NUMBER: ML15205A371 CONTACTS: David Proulx Lara Uselding (817) 200-1561 (817) 200-1519 David.Proulx@nrc.gov Lara.Uselding@nrc.gov