ENS 43013

v t e ENS Event
19:30 Nov 27, 2006
Title	Momentary Loss of Shutdown Cooling Due to Rhr Isolation Signal
Event Description	On November 27, 2006 Fort Calhoun Station was on shutdown cooling, while in the process of moving the plant from Mode 3 to Mode 4 to fix a leak on an In-Core Instrument (ICI) Grayloc fitting. At 1327 Reactor Coolant Pump RC-3B was secured. At 1330, the last Reactor Coolant Pump (RC-3A) was secured. Once the reactor coolant pumps were secured, spray to the pressurizer was lost. This loss of pressurizer spray caused pressure in the pressurizer to rise; the systems pressure interlock caused HCV-347, Shutdown Cooling Loop 2 Outboard Isolation Valve, and HCV-348, Loop 2 to Shutdown Cooling Isolation Valve to close due to pressurizer pressure being greater than 250 psia. At 1330 the Control Room entered AOP-19 for a Loss of Shutdown Cooling. The control room operators initiated auxiliary spray, lowered pressure, reopened HCV-347/348, and started Low Pressure Safety Injection Pump SI-1A. At 1342 shutdown cooling was reestablished. At 1352 all conditions to exit AOP-19 were met and the procedure was exited. During the 12 minutes that shutdown cooling was lost the highest pressure reached in the RCS was 254 psia up from 233 psi and the highest temperature was 135 degrees, up from 134 degrees as read on the core exit thermocouples. The licensee informed the NRC Resident Inspector.

ENS 43013 +/-
Where
Ft Calhoun Nebraska (NRC Region 4)
Reporting

10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat
Time - Person (Reporting Time:+-2.72 h-0.113 days <br />-0.0162 weeks <br />-0.00373 months <br />)
Opened:	Chuck Marasco 16:47 Nov 27, 2006
NRC Officer:	Steve Sandin
Last Updated:	Nov 27, 2006
43013 - NRC Website
v • d • e

v t e Emergency Notification System
Fort Calhoun with 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat
WEEKMONTHYEAR2016-03-18T16:28:00 [Table view]
[ENS list for Fort Calhoun]

Navigation menu