Grand Gulf Nuclear Station Enters Refueling Outage in Hot Shutdown after Reactor Vessel Water Loss

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Employees at the Grand Gulf power plant began reducing power to enter a scheduled refueling outage under unexpected conditions on February 19th.  The Unit was in the process of shutting down for its 18th refueling outage.  The reactor had to be manually scrammed due to lowering reactor water levels, in some areas over 35 inches below normal levels.

The water levels inside of the reactor were restored after initiating the “A” RFP into service, but the root cause of the “B” RFP problem has yet to be determined.  Workers will perform hundreds of maintenance activities during the outage and replace more than one third of the fuel in the reactor.

A new turbine rotor and refurbished main generator will also be at a $724 million price tage, whose cost will be shared among the joint owners of Grand Gulf, including Entergy Mississippi and the South Mississippi Electric Power Association, Grand Gulf communication specialist, Suzanne Anderson said in December.

The work is being down as a result of an application for license renewal that was filed in November 2011.  The Nuclear Regulatory Commission has opened a public comment period on Grand Gulf Nuclear Station’s license to operate for another 20 years.

The outage and work at the Entergy plant is expected to last several weeks.  Refueling outages are required for all nuclear reactors every 18 to 24 months.  In 2011, Grand Gulf  the subject of 25 Plant Inspection Findings.

Grand Gulf Nuclear Station Inspection Findings in 2011

Failure to Take Timely Corrective Actions for Reactor Core Isolation Cooling System Venting  Inspection Report# : 2011006 (pdf)

Failure to Submit a Licensee Event Report for an Inoperable Reactor Core Isolation Cooling System  Inspection Report# : 2011006 (pdf)

Inadequate Corrective Action for a Leak on the Division II Emergency Diesel Generator Lube Oil Sump  Inspection Report# : 2011006 (pdf)

Failure to Establish Preventative Maintenance for Components Used in Critical Applications  Inspection Report# : 2011004 (pdf)

Failure To Provide An Adequate Alternative Shutdown Procedure  Inspection Report# : 2011007 (pdf)

Failure To Assure Equipment Required For Postfire Safe Shutdown Was Protected Against Fire Damage  Inspection Report# : 2011007 (pdf)

Failure to Take Timely Corrective Actions to Protect Safe Shutdown Equipment From Fire Damage  Inspection Report# : 2011007 (pdf)

Inadequate Corrective Actions To Assure Postfire Safe Shutdown Inspection Report# : 2011007 (pdf)

Failure to Perform an Adequate Inspection of Probable Maximum Precipitation Door Seals Protecting Safety Related Equipment Inspection Report# : 2011003 (pdf)

Failure to Follow Scaffold Control Procedure Inspection Report# : 2011003 (pdf)

Failure to Identify Conditions Adverse to Fire Protection Inspection Report# : 2011003 (pdf)

Failure to Ensure that Safety Related Manholes were Properly Sealed to Prevent the Entry of Flammable Liquid Inspection Report# : 2011003 (pdf)

Failure to Provide Adequate Procedures for High Pressure Core Spray Minimum Flow Valve Surveillance Testing  Inspection Report# : 2011003 (pdf)

Loose Fuse Clips in Division 3 Emergency Diesel Generator  Inspection Report# : 2011003 (pdf)

Failure to Assure Configuration Control of Safety Related Systems  Inspection Report# : 2011003 (pdf)

Failure to Follow a Procedure Resulting in the Inoperability of the Reactor Core Isolation Cooling System Primary Containment Isolation Valve  Inspection Report# : 2011003 (pdf)

Failure to Update Available Low Pressure Coolant Injection Loops in the Updated Final Safety Analysis Report Inspection Report# : 2011002 (pdf)

Failure to Demonstrate Maintenance Effectiveness of Train B Control Room Air Conditioner Inspection Report# : 2011002 (pdf)

Failure to Prevent Recurrence of Control Room Air Conditioner Compressor Tripping Due to Low Oil Pressure Inspection Report# : 2011002 (pdf)

Failure to Ensure Correct Fuses were Installed in the Hydrogen Igniter Control Circuits Inspection Report# : 2011004 (pdf)

Failure to Perform Preventative Maintenance on the Fuel Handling Bridge Paddle Switch Inspection Report# : 2011004 (pdf)

Transient Combustible Stored in the Fire Exclusion Zone Near the Independent Spent Fuel Storage Installation Inspection Report# : 2011002 (pdf)

Inadequate Design Control for the Mitigation Monitoring System Modification  Inspection Report# : 2011002 (pdf)

Failure to use a qualified radiation protection technician to provide direct continuous coverage of work in a locked high radiation area Inspection Report# : 2011002 (pdf)

 

Power Reactor Event Number: 47679
Facility: GRAND GULF
Region: 4 State: MS
Unit: [1] [ ] [ ]
RX Type: [1] GE-6
NRC Notified By: FRANK WEAVER
HQ OPS Officer: STEVE SANDIN
Notification Date: 02/19/2012
Notification Time: 22:00 [ET]
Event Date: 02/19/2012
Event Time: 19:04 [CST]
Last Update Date: 02/19/2012
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(2)(iv)(B) – RPS ACTUATION – CRITICAL
50.72(b)(3)(iv)(A) – VALID SPECIF SYS ACTUATION
Person (Organization):
GEOFFREY MILLER (R4DO)
Unit SCRAM Code RX CRIT Initial PWR Initial RX Mode Current PWR Current RX Mode
1 M/R Y 23 Power Operation 0 Hot Shutdown

 

MANUAL REACTOR SCRAM DURING SHUTDOWN DUE TO LOWERING REACTOR VESSEL WATER LEVEL (RVWL)

“On 2/19/2012 at 1904 hrs [CST] the reactor was manually scrammed from approximately 23% core thermal power due to lowering reactor water level. All control rods fully inserted and all systems actuated and operated as designed. The Reactor Core Isolation Cooling System was manually initiated to assist in level control. No safety relief valves actuated. Reactor level and pressure are currently being controlled within normal bands. Group 2 and 3 RHR Isolation signals were received, however no valve movement occurred since the affected valves are normally closed.

“This event is reportable under 10CFR50.72(b)(2)(iv)(B) for the reactor trip and 50.72(b)(iv)(A) for the manual start of the core isolation cooling system.”

The lowest Reactor Vessel Water Level [RVWL] observed was -38 inches WR [Wide Range]. RVWL was restored by placing the “A” Reactor Feed Pump [RFP] in service. The “B” RFP which had been operating was secured for troubleshooting. The Unit was in the process of shutting down for its scheduled Refueling Outage #18.

The NRC Resident Inspector was in the control room at the time of the transient.

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