Event Notification Report for April 18, 2013

LOW PRESSURE CORE SPRAY INOPERABLE

"On 4/18/2013, while attempting to raise Unit 1 reactor level with the Low Pressure Core Spray (LPCS) system, LPCS injection valve 1E21-F005 failed to open as required when the associated control switch was held in the 'OPEN' position. The Unit Supervisor declared the LPCS system inoperable, and the appropriate Technical Specification time clocks were entered. Troubleshooting determined that the problem was a faulty control switch.

"The control switch has been replaced and LPCS returned to an operable status.

"Initial review of this event determined that it was not reportable; however, subsequent review caused the event to be re-evaluated and classified as reportable under 10CFR50.72(b)(3)(v)(D) and 50.73(a)(2)(v)(D) as an event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident.

"The station is continuing to evaluate the reportability of this event."

The licensee notified the NRC Resident Inspector.

LOST POLONIUM-210 STATIC ELIMINATOR SOURCE

Prefix Corporation uses static control ionizers for applying coatings in some of its product processes. These static control ionizers are leased from NRD LLC and contain less than 0.1 millicuries of Polonium-210. In early April, 2013, Prefix was preparing to return one of its leased Nuclecel Ionizers to NRD and discovered it was missing. The source was last used in November of 2012. A search was conducted for the source without success and Prefix considers the source to be lost. The source is small and cylindrical and could have rolled off its storage location onto the floor and been swept-up as trash. Prefix sent a written notification to NRC Region 3 on April 18, 2013, but had not previously reported the event to the NRC Operations Center.

THIS MATERIAL EVENT CONTAINS A "LESS THAN CAT 3" LEVEL OF RADIOACTIVE MATERIAL

Sources that are "Less than IAEA Category 3 sources," are either sources that are very unlikely to cause permanent injury to individuals or contain a very small amount of radioactive material that would not cause any permanent injury. Some of these sources, such as moisture density gauges or thickness gauges that are Category 4, the amount of unshielded radioactive material, if not safely managed or securely protected, could possibly - although it is unlikely - temporarily injure someone who handled it or were otherwise in contact with it, or who were close to it for a period of many weeks. For additional information go to http://www-pub.iaea.org/MTCD/publications/PDF/Pub1227_web.pdf

INADVERTENT ACTIVATION OF AN EMERGENCY SIREN

"On 4/18/13 at 2312 EDT, Emergency Siren 955 inadvertently actuated for approximately 5 minutes. The cause of the actuation is under investigation but believed to be due to rain water intrusion. The siren stopped on its own, and was subsequently disconnected by the siren vendor to prevent further erroneous actuation. The siren remains out service and is the only siren out of service within the 10 mile Emergency Planning Zone (EPZ). There are a total of 70 sirens.

"The siren is located in a state park not currently inhabited by campers; due to the siren location and time of activation the impact on the surrounding population was minimal. The event was therefore determined to not be reportable.

"A subsequent review of the event, considering communications made between Cook Nuclear Plant and the Berrien County 911 Dispatch Center, as well as recent industry operating experience of similar events, was performed; its conclusion was to conservatively make a report under 10 CFR 50.72(b)(2)(xi).

"The licensee has notified the NRC Resident Inspector."

LOSS OF ASSESSMENT CAPABILITY DUE TO FAILURE OF A RADIATION MONITOR BYPASS PUMP

"System(s) Affected: Site Stack Radiation Monitor, RM-8169

"Causes: Failure of radiation monitor bypass pump.

"Effect of Event on Plant: Loss of assessment capabilities from radiation monitor.

"Actions taken or planned: Repair of radiation monitor.

"Additional information: Radiation monitor inoperable at 2030 [EDT] on 4/16/13. Further review identified the reportable condition."

The licensee informed the State of Connecticut, Waterford dispatch, and the NRC Resident Inspector.

PIN HOLES LEAKS IDENTIFIED IN HIGH PRESSURE CORE SPRAY SYSTEM

"This report is being made pursuant to 10CFR50.72(b)(3)(v)(D), 'Event or Condition that could have prevented fulfillment of a Safety Function needed to Mitigate the Consequences of an Accident', and also 10CFR50.72(b)(3)(ii)(A), 'Degraded or Unanalyzed Condition'. At 1400 [CDT] on 4/18/13, 3 pin hole leaks were identified in the Unit 2 High Pressure Core Spray System (HPCS) minimum flow valve flow line, between the minimum flow valve and the Primary Containment Suppression Pool in the Reactor Building Raceway. The leak is approximately ¢ gallon per minute. This could have prevented the Primary Containment, a single train safety system, from performing its design function, and also results in the nuclear power plant, including its principal safety barriers, being seriously degraded. In addition, the Unit 2 HPCS System, a single train system, has been declared inoperable, and has also lost function due to the minimum flow line leak. This is reportable as an 8 hour ENS [Event Notification System] notification.

"At the time the leak was identified, Both LaSalle Unit 1 and 2 are in Hot Shutdown, following a loss of Offsite Power on 4/17/13. Unit 2 will remain shut down until repairs are made to the Unit 2 HPCS minimum flow line leak."

Unit 2 will be placed in Mode 4 and remain in Mode 4 until repairs are complete.

The licensee has informed the NRC Resident Inspector.