Event Notification Report for November 16, 2020

This material event contains a "Less than Cat 3" level of radioactive material.

EN Revision Imported Date: 11/17/2020

EN Revision Text: AGREEMENT STATE REPORT - MISSING DENSITY GAUGE

The following was received from the Colorado Department of Public Health and Environment (CDPHE) via email:

"[A Troxler 3440 (SN 23106) containing not more than 333 MBq (9 mCi) of cesium-137 and 1.63 GBq (44 mCi) of americium-241:beryllium; or 2.44 MBq (66 microCi) of californium-252] was reported missing after a licensee was unable to account for it during a routine inventory check. The material was noticed missing at approximately 1000 MDT on Wednesday, October 14, 2020. The event was reported to the CDPHE at approximately 1700 on October 14, 2020.

"No signs of a burglary at the facility are present. The last entry for the gauge in the utilization log is August 19, 2020. The licensee suspects that a former employee stole the gauge, the employee to last check-out the gauge was terminated on bad terms.

"The licensee is in the process of reporting the theft to the local police."

* * * UPDATE ON 11/16/10 AT 1513 EST FROM DEREK BAILEY TO THOMAS KENDZIA * * *

The following was received from the Colorado Department of Public Health and Environment (CDPHE) via email:

"Following a police investigation the nuclear gauge was anonymously returned to the owner. On November 16, 2020, the missing nuclear density gauge was found chained to the fence at the Olsson office. It was discovered at 1015 MDT Olsson examined the gauge and found it to be in the proper original packaging with no apparent damage to the gauge's packaging, components, or sources of radiation. It was determined that the gauge was returned at approximately 2330 MDT November 15, 2020."

Notified the R4DO (Taylor), NMSS Events Notification (email), and ILTAB (email)

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

AUTOMATIC REACTOR SCRAM DUE TO HIGH REACTOR PRESSURE SIGNAL

"At 0245 EST on November 13, 2020, the Limerick Unit 1 reactor automatically scrammed on a valid Reactor High Pressure signal (1096psig). The Reactor High Pressure signal was caused by the closure of the 1B Inboard Main Steam Isolation Valve (MSIV), causing reactor pressure to rise, exceeding the Reactor Protection System (RPS) setpoint of 1096psig.

"The shutdown was normal and the plant is stable in Hot Shutdown with normal pressure control via the Main Steam Bypass Valves to the Main Condenser and normal level control using the Feedwater System.

"The closure of the 1B Inboard MSIV appears to have been caused by a loss of Primary Containment Instrument Gas (PCIG) pneumatic supply to the valve."

The licensee notified the NRC Resident Inspector, and will be notifying Berks, Chester, and Montgomery Counties, as well as the Pennsylvania Emergency Management Agency.

AUTOMATIC ACTUATION OF THE EMERGENCY DIESEL GENERATORS

"At 0144 EST on November 15, 2020, with Unit 1 in Mode 1 at 100 percent power and Unit 2 in Mode 5 at 0 percent power, an actuation of the Emergency Diesel Generator (EDG) system occurred while transferring the 2A-A 6.9 kV Shutdown Board (SDBD) from the maintenance feed to its normal power supply. The reason for the 2A-A 6.9 kV SDBD failing to transfer to the normal power supply is under investigation. The EDGs automatically started as designed when the valid actuation signal was received.

"This event is being reported in accordance with 10 CFR 50.72(b)(3)(iv)(A) as an event that results in a valid actuation of the EDGs.

"There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified."

PART 21 REPORT - FAILURE OF AIR CONDITIONER COMPRESSOR HEAD GASKET

The following is a synopsis of the information received from the supplier.

On August 26, 2020, H. B. Robinson Generating Station, Unit 2 experienced a failure during post maintenance testing of a newly installed air conditioning compressor, which serves one of the Control Room HVAC units. Robinson plant contacted QualTech (the supplier) on September 22, 2020, detailing the findings of their investigation which indicated an incorrect head gasket had been installed, allowing high pressure gas to discharge to the low pressure side.

QualTech NP reviewed the investigation and agrees, the incorrect gasket was installed. The root cause was determined to be an improper dedication plan of the gaskets, not recognizing the delta between the 'left' and 'right' head gaskets. QualTech has taken action to revise the dedication plan. This is the only compressor unit of this model sold. No other similar failures have been reported. QualTech believes this to be an isolated case.

For further information contact:
Tim Franchuk
Quality Assurance Director
QualTech NP, Curtiss-Wright Nuclear Division
(513) 528-7900 x176