Event Notification Report for April 17, 2013

AGREEMENT STATE REPORT - SHUTTER MECHANISM FAILURE ON A FIXED GAUGE

The following information was received from the State of Iowa via fax:

"On April 18, 2013, the licensee (3M Company - Ames) reported to the Iowa Department of Public Health that a shutter mechanism had failed to close on a fixed gauge at their Ames, Iowa facility. The device is a Thermo EGS Gauging, model ASC-185, serial number KA1527 containing a nominal activity (May 25, 2006) of 1250 millicuries Krypton-85. The licensee's RSO and trained maintenance staff proceeded to troubleshoot the cause of the failure to close. They identified that screws holding the shutter mechanism had become stripped and loose causing the source shutter to not operate properly. The gauge was removed and is now stored in a locked cabinet under the RSO's control. The RSO is currently pursuing the purchase of new screws so that the shutter mechanism can be repaired. Additional corrective actions include a more detailed inspection of the shutter screws during six month inspections."

The sealed source (Krypton-85) is manufactured by Isotope Products Lab, S/N NER-588.

IA Item Number: IA130003

NOTIFICATION OF UNUSUAL EVENT DECLARED DUE TO LOSS OF OFFSITE POWER FROM A LIGHTNING STRIKE

"LaSalle Unit 1 and LaSalle Unit 2 have both experienced an automatic reactor scram, in conjunction with a loss of offsite power. This was caused by an apparent lightning strike in the main 345kV/138kV switchyard during a thunderstorm. 138kV line 0112 has been inspected in the field, and heavy damage has been noted on the insulators on two of the three phases on a line lightning arrestor line side.

"The plant systems have all responded as expected. All five diesel generators started, and have loaded on to their respective buses as designed. All rods went full in on both units during the respective scrams. HPCS [High Pressure Core Spray] system was started on each unit and automatically aligned for injection for initial level control."

The MSIVs [Main Steam Isolation Valves] are shut on both units with decay heat being removed via the safety relief valves. Suppression pool cooling is in progress.

The licensee will notify the NRC Resident Inspector and has notified the State.

Notified DHS, FEMA, USDA, HHS, DOE, NICC, EPA, and Nuclear SSA via email.

* * * UPDATE FROM DON PUCKETT TO VINCE KLCO AT 2113 EDT ON 4/17/2013 * * *

"In addition to information [previously provided], LaSalle Unit 2 received a high drywell pressure signal [1.77 psig] due to loss of containment cooling from the loss of power. At the time of this high drywell pressure signal, high pressure core spray pump and 2B residual heat removal [RHR] pump was already in operation, the low pressure core spray system and 2A residual heat removal system was secured and [placed] in pull to lock. When the signal was satisfied the ECCS [Emergency Core Cooling Systems] signal was processed but only the 2C RHR pump would have started. In this case, the 2C RHR pump tripped when the signal was received. There is no evidence of reactor coolant leakage. There was no additional ECCS systems discharging into the RCS [Reactor Coolant System]. As [initially stated], level was controlled using High Pressure Core Spray and level control is now being maintained using the Reactor Core Isolation Cooling [RCIC] systems. The 2C RHR pump trip is under investigation.

"Due to the initial loss of offsite power for both Unit 1 and Unit 2 reported at 1511 [CDT], multiple containment isolation valves isolated and closed as expected. Once initial containment isolations were verified, two Unit 2 primary containment vent and purge valves were opened to vent the Unit 2 containment. Once Unit Two containment pressure reached 1.77 [psig], these two vent valves isolated as expected.

"Due to the loss of offsite power, the Station Vent Stack Wide Range Gas Monitor (WRGM) and the Standby Gas Treatment Wide Range Gas Monitor (VGWRGM) also lost power. Manual sampling has been implemented and power is restored to the VGWRGM, however the VGWRGM has not been declared operable yet. Normal radiation levels have been reported from the manual sampling. [This is being reported in accordance with 10CFR50.72(b)(3)(xiii).]"

The licensee notified the NRC Resident Inspector and the State of Illinois.

Notified the R3 IRC, NRR EO(Skeen), IRD MOC (Grant).

* * * UPDATE AT 0057 EDT ON 04/18/13 FROM MIKE LAWRENCE TO S. SANDIN * * *

"After the Unit 2 primary containment vent and purge system isolated on the Unit 2 containment High Pressure signal, Venting of the Unit 1 primary containment was commenced. At 2005 CDT, Unit 1 primary containment pressure reached the Group 2 primary containment isolation system setpoint (1.77 PSIG) causing the primary containment vent and purge valves being used to vent the Unit 1 containment to isolate. Unit 1 primary containment venting was being performed through the Standby Gas Treatment system which is a filtered system.

"In addition to the primary containment isolation signal on high drywell pressure, an ECCS initiation on high drywell pressure also occurred. The ECCS signal resulted in an auto start of the 1C RHR system. The 1B RHR system was already running in suppression pool cooling mode. 1A RHR and LPCS had been secured to prevent overloading the common diesel generator for division 1. The common diesel generator supplies both Unit 1 and Unit 2 division 1 ESF busses."

The licensee informed the NRC Resident Inspector. Notified NRR EO (Skeen), IRD MOC (Grant) and R3IRC (Louden).

* * * UPDATE AT 0947 EDT ON 04/18/13 FROM JUSTIN FREEMAN TO PETE SNYDER * * *

"LaSalle has terminated the unusual event which was initiated at 1511 on 4/17/13 and reported under EN 48939. This unusual event has been terminated based on meeting the following established criteria. This report is being made in accordance with 10CFR50.72.(c)(1)(iii).

"1) Off-site power has been restored to all ESF busses
"2) Fuel Pool Cooling has been restored on both units
"3) Primary Containment Chillers have been restored on both units
"4) Drywell pressure is less than ECCS initiation setpoint
"5) ECCS signals cleared to allow diesels to be placed in stand by

"Recovery of remaining plant systems will be managed through the Outage Control Center (OCC)."

The licensee informed the NRC Resident Inspector. Notified R3DO (Orth), NRR EO (Chernoff), IRD (Grant), DHS, FEMA, USDA, HHS, DOE, NICC, EPA, and Nuclear SSA via email.

* * * UPDATE AT 1711 EDT ON 4/21/2013 FROM GREG LECHTENBERG TO MARK ABRAMOVITZ * * *

"In addition to the 10 CFR 50.72 Sections initially identified, the Loss of Offsite Power was also reportable under 10 CFR 50.72(b)(3)(v)(D) as an event or condition that could have prevented the fulfillment of the safety function of systems needed mitigate the consequences of an accident. This event is considered a safety system functional failure for both Units 1 and 2."

The licensee will notify the NRC Resident Inspector.

Notified the R3DO (Orth).

DEGRADED CONDITION DUE TO SUSPECTED VALVE BODY LEAKAGE

"On April 17, 2013 at 1600 [EDT], while performing a valve inspection/repair of the Unit 2 'A' Reactor Coolant Loop Fill Valve (2- RC-HCV-2556A), the as-found inspection results identified evidence of a suspected flaw causing leakage from the valve body to the threads of a stud housing of the valve. This valve is a 2 [inch] 316 SS [Stainless Steel] cast ASME XI (Class 1) 1500 psi valve body of a globe style design. Due to this design and the installed orientation, the RCS pressure medium fills the upper portion of the valve bonnet where the leak is located during normal plant operations. Therefore, this leakage would be considered pressure boundary leakage. 2-RC-HCV-2556A is currently isolated from the Reactor Vessel and is at atmospheric pressure.

"This inspection was performed in response to dry discolored boric acid identified during the normal operating pressure boric acid accumulation inspection procedure during the Spring 2013 Unit 2 refueling outage shutdown. An engineering evaluation of the suspected defect will be performed and corrective actions implemented.

"This event is reportable in accordance to 10CFR50.72(b)(3)(ii)(A) for, 'Any event or condition that results in the condition of the nuclear power plant, including its principal safety barriers, being seriously degraded'."

The licensee notified the NRC Resident Inspector and local County Commissioners.

* * * RETRACTION FROM BOB PAGE TO CHARLES TEAL ON 6/12/13 AT 1109 EDT * * *

"Event Number 48940 was made on April 17, 2013 in accordance with 10CFR50.72(b)(3)(ii)(A) to document a suspected flaw resulting in RCS pressure boundary leakage on Unit 2 'A' Reactor Coolant Loop Fill Valve (2-RC-HCV-2556A). North Anna Power Station is retracting this notification following completion of a cause analysis and metallurgical examination. The analysis determined that the valve leakage was due to the body-to-bonnet gasket joint. The original valve body was especially susceptible to gasket creep, which lead to a loss of sufficient sealing stress. This resulted in body-to-bonnet leakage, not a through-wall leak. Based on this analysis, the reporting requirements of 10CFR50.72(b)(3)(ii)(A) are not met and this event report is being retracted.

"The licensee has notified the NRC Resident Inspector."

Notified R2DO (Ehrhardt).