Event Notification Report for December 16, 2010

PLANNED MAINTENANCE TO MICROWAVE RADIO SYSTEM AFFECTING EOF, STATE AND COUNTY FACILITIES

"This is an eight hour report per 10 CFR 50.72 (b)(3)(xiii). Calvert Cliffs will be implementing scheduled maintenance to the microwave radio system to improve reliability of the system at the Emergency Operations Facility (EOF), State and County facilities.

"This work will require that the microwave radio system at the EOF be removed for a period of approximately 4 to 6 hours. During this time, the following systems will be impacted for the duration of maintenance:

1. The plant's (e.g., Control Room, Technical Support Center (TSC), Simulator) Dedicated Offsite Agency telephones will be out of service. (EOF's system will continue to function)

2. 800 MHz desk set radios at the EOF only will be out of service.

3. 153.44 MHz frequency at the EOF only will be out of service. (backup for MEMA and MDE)

4. MIDAS Terminal (Meteorological Data) located in the Dose Assessment Office at the EOF will be out of service.

5. TSC Computer data transfer to the EOF only will be out of service.

"Once the scheduled maintenance starts, the systems (listed above) can be returned to service within 1 hour.

"Should an emergency be declared during this period, the Control Room will continue to have the capability to make the event notification to the offsite agencies within 15 minutes using either commercial telephone lines or the 800 MHz radio console (includes the 153.44 MHz frequency). The Emergency Preparedness communications procedure provides a chart listing the communication devices available and the order in which the process is to be implemented. MIDAS (Meteorological Data) will continue to be operational at the site and can be obtained by contacting the Control Room or TSC. The ERPIPs also provide a backup process and the instructions necessary for the EOF Dose Assessment Office to obtain Meteorological Data. Plant data can be obtained from the CR or TSC and will continue to be downloaded from the plant computer to the ERO SharePoint site.

"All work associated with this microwave radio maintenance will be performed in an expeditious manner consistent with the goal of minimizing unavailability of the systems listed above. A test of the offsite agency notification devices in the Control Room will be made prior to the commencement of the maintenance. A test of all systems will be performed at the completion of the maintenance.

"All EOF responders and Control Room personnel have been briefed on this work and expected contingent actions.

"This job will start on Thursday, December 16, 2010 at approximately 8:00 am. We anticipate that all work will be completed by 2:00 pm on the same day, including testing of the system. We will provide a notification update upon completion of the job."

The licensee informed the NRC Resident Inspector and the affected State and County Agencies.

* * * UPDATE AT 1248 ON 12/16/2010 FROM TOM JONES TO MARK ABRAMOVITZ * * *

The maintenance and testing was completed satisfactorily at 1130 EST. The licensee notified the NRC Resident Inspector.

Notified the R1DO (Holody).

BOTH HF DETECTORS IN GHS TEST LOOP FAILED TO BE AVAILABLE AND OPERABLE

"During a performance of internal procedure to verify functionality of installed HF detectors in the Test Loop (TL) Gas Handling System (GHS) room, it was discovered at about 1044 [EST on] 12/16/10, that both IROFS TL-HF-01 and IROFS TL-HF-02 failed to pass internal test requirements. At least one of these HF detector IROFS is required to be available and operable to meet 10 CFR 70.61 performance requirements.

"The installed HF detector electrochemical sensors performance appears to have been degraded as a result of low room 'relative humidity' as a result of unusually cold outdoor conditions. The independent IROFS TL-HF-04 (an administrative control) remained intact, thus no unsafe condition existed. While one documented IROFS remained functional (TL-HF-04) to assure the consequence of chemical and radiological exposure is maintained low, TL-HF-04 could not alone meet 10 CFR 70.61 performance requirements.

"No loss of UF6 containment occurred in affected process equipment. The degradation of TL-HF-01 and TL-HF-02 was observed as part of the IROFS' periodic surveillance. This event is therefore being reported pursuant to the requirements of 10 CFR 70 Appendix A(b)(2) within 24 hours. The affected TL bench scale experiment equipment will remain shutdown pending further investigation and implementation of associated corrective actions.

"SAFETY SIGNIFICANCE OF EVENTS - Low safety significance - the discovery did not result in an unsafe condition.

"SAFETY EQUIPMENT STATUS - Required IROFS TL-HF-01 and TL-HF-02 functionality being re-established.

"STATUS OF CORRECTIVE ACTIONS - The affected TL process operation remains shutdown pending investigation and implementation of corrective actions."

The licensee will be contacting NRC Region 2, state and local government agencies.