Event Notification Report for December 11, 2013

MISSING LICENSED MATERIAL

"Two Trijicon gun scopes, source ID# 6-53953 and 110-59164, both non-exempt sources, were identified as being missing from a Security rifle scopes inventory. Each scope had a [tritium] activity quantity of 57.766 milliCuries (mCi) and 60.528 milliCuries (mCi), respectively. The radioactive material is an integral part of the scope from manufacture. Scope source ID# 110-59164 was recovered, and scope source ID# 6-53953 remains unrecoverable.

"The activity quantity for the these gun scope exceeds the 10 times the 10 CFR 20, Appendix C quantity, but is [less than] 1,000 times the regulatory criteria of Appendix C and therefore is being reported in accordance with 10 CFR 20.2201(a)(ii).

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

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

FITNESS FOR DUTY REPORT INVOLVING A LICENSED EMPLOYEE

"A licensed employee had a confirmed positive test for illegal drugs during a random fitness-for-duty test. The employee's access to the plant has been terminated.

"The licensee notified the NRC Resident Inspector."

INVALID ACTUATION OF PRIMARY CONTAINMENT ISOLATION SYSTEM (PCIS) VALVES DURING I&C MAINTENANCE

"This 60-day report, as allowed by 10 CFR 50.73(a)(1), is being made per 10 CFR 50.73(a)(2)(iv)(A) to describe an unplanned, invalid closure of Unit 2 Primary Containment Isolation System (PCIS) valves.

On December 11, 2013, at 0818 EST, an instrument technician was adjusting the output voltage of the 'A' 120-volt Reactor Protection System (RPS) motor-generator (MG) set, which is the normal power supply for the 'A' RPS bus. As the adjustment potentiometer was being moved, output voltage momentarily dropped below the setpoint of an Electrical Protection Assembly (EPA) on the 'A' RPS bus. The EPA tripped and removed power from the 'A' RPS bus. Removing power from the RPS bus resulted in PCIS valves receiving a close signal. Affected valves or systems were a Reactor Water Sample valve, Main Steam Line Drain valves, Containment Atmospheric Control System valves, Drywell Equipment Drain and Floor Drain valves, and a Reactor Water Cleanup System valve.

"Other systems affected were Standby Gas Treatment, Control Room Emergency Ventilation, and Radiation Monitoring on Main Steam Lines, Main Stack, Reactor Building Vent, and Main Condenser. All actuations that resulted from the loss of power to RPS Bus 'A' were completed as expected.

"This event resulted from the attempt to adjust the voltage control potentiometer on the RPS MG set. When a technician attempted to adjust the potentiometer, the movement caused the RPS MG set to momentarily and unexpectedly experience a low voltage on the output, tripping the output breakers.

"Power was restored to the affected RPS bus by 0858 EST on December 11, 2013, and all affected systems were subsequently returned to service.

"Since no actual plant or process conditions existed which would have caused the various actuations described above, this event is being reported per 10 CFR 50.73(a)(1) as an invalid actuation.

"This issue has been entered into the site Corrective Action Program (CR 651284) for evaluation and implementation of further corrective actions.

"The NRC Resident Inspector has been informed of this notification."

60 DAY REPORT FOR AN INVALID MAIN STEAM LINE ACTUATION

"The following event description is based on information currently available. If through subsequent reviews of this event additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10 CFR 50.73.

"This telephone notification is being made pursuant to the reporting requirements of 10 CFR 50.73(a)(2)(iv)(A) to describe an invalid actuation of the Palo Verde Nuclear Generating Station Unit 2 'A' train Main Steam and Feedwater Isolation System (MSFIS) logic.

"On December 11, 2013, at approximately 2011, Mountain Standard Time, Unit 2 was shut down in Mode 4 with Reactor Coolant System (RCS) temperature at approximately 425 degrees Fahrenheit and 1900 pounds per square inch absolute. While starting up the plant following completion of repairs to the 1A reactor coolant pump, an invalid actuation of the 'A' train MSFIS fast close logic occurred due to a random electrical failure in the 'A' train MSFIS logic cabinet. This resulted in the closure of all four Main Steam Isolation Valves and the two 'A' train Economizer Feed Water Isolation Valves. No other engineered safety feature actuations occurred and none were required. The invalid actuation was initiated by a ground fault in a 30-volt direct current power supply in the 'A' train MSFIS Logic cabinet. Repairs were completed on December 12, 2013.

"This was a complete actuation of 'A' train MSFIS equipment and all the affected equipment responded as designed. RCS temperature and pressure were maintained stable using atmospheric dump valves. Feed water to the steam generators was being provided by Auxiliary Feed Water and was not affected by the event.

"The NRC Resident Inspector has been notified."