Event Notification Report for July 11, 2012

CRITICALITY HORNS RENDERED INOPERABLE DUE TO LIGHTNING STRIKE

"At approximately 1740 EDT on 7/11/12, lightning strikes near the Wilmington Field Service Center (WFSC) rendered several alarm annunciators (horns) of the Criticality Accident Alarm System (CAAS) inoperable. There are no active fissile material operations in WFSC, thus no unsafe condition existed.

"Until the system is repaired, personnel have either been removed from the affected area or other compensatory measures have been established. Longer term preventative actions are being evaluated.

"This event is being reported pursuant to the requirements of 10CFR70.50(b)(2)."

The licensee will notify NRC R2 (Thomas), and the State and Hanover County Emergency Management Agencies.

OFFSITE NOTIFICATION DUE TO DISCOVERY OF AMMONIA FOUND IN GROUNDWATER

"A report to the State of New Jersey was made on July 11, 2012 at 1157 EDT. The report was in accordance with Attachment 16 of the ECG (Event Classification Guide). The report was due to 4-5 ppm ammonia found in ground water on an excavation site. Samples were obtained from ground water in the hole. Estimate of leakage into hole is 2 ounces per minute."

The licensee believes the ammonia is from leftover de-icing salt. An estimated 100 gallons of water was pumped from the hole into a treated system. The NRC Resident Inspector and the Lower Alloways Creek township was notified.

ANALYSIS OF INTERNAL CONTAINMENT SUPPORT BEAM EXCEEDS LOAD COMBINATION LIMIT

"Fort Calhoun Station is making an 8-hour verbal report per 10CFR50.72(b)(3)(ii)(B) Unanalyzed Condition. An internal containment support beam (B-22) has been identified by the station as not passing the required load combination as stated in the USAR for at power conditions. Beam B-22 is the designation for the two beams that directly support Safety Injection Tanks 6B and 6D.

"This beam was also identified as having potential loading conditions outside the allowable limits for the load combination for shutdown conditions. Specifically, it was determined that in order to bring the beam loading to within acceptable levels, the allowable floor live load would need to be reduced from the current designated load distribution of 200 pounds per square foot (psf) to 140 psf. A walkdown of the area by Design Engineering estimates the current floor live load is approximately 100 psf.

"Compensatory actions are being established to remove any equipment that is contributing to current live loading of the support beam and to isolate and post the affected area to ensure no equipment is stored without engineering analysis."

The licensee has notified the NRC Resident Inspector.

CABLE ASSOCIATED WITH 4KV SHUTDOWN BOARD ROUTED INCORRECTLY

"On July 11, 2012, during the [National Fire Protection Association] NFPA 805 transition review process for the Browns Ferry Nuclear Plant (BFN), it was discovered that a cable associated with 4kV Shutdown Board B cross-tie breaker 1828 differential lockout contacts was not routed in accordance with the Appendix R Separation Analysis. Specifically, the cable was determined to be routed in Fire Zone 03-02 and is considered to be an unanalyzed condition.

"In the event of an Appendix R fire in Fire Zone 03-02, fire damage to cables associated with 4kV Shutdown Board B cross-tie breaker 1828 and the 4kV Shutdown Board 3EB cross-tie breaker 1848 could occur. A fire induced hot short could cause spurious closure of breaker 1828. Fire damage to cable associated with 4kV Shutdown Board B cross-tie breaker 1828 differential lockout contacts could also result in the loss of the breaker trip function. This condition may result in the following two failures:

"1) If breaker 1828 spuriously closed, it could close onto a fault, since the cross-tie power cables from breaker 1828 on 4kV Shutdown Board B to Breaker 1848 on 4kV Shutdown Board 3EB are routed through Fire Zone 03-02 and would be subject to a fire induced fault, if energized. This could result in the trip of Diesel Generator B output breaker 1822 and deenergization of the 4kV Shutdown Board B.

"2) Breaker 1848 on 4kV Shutdown Board 3EB is also vulnerable to spurious closure in the event of an Appendix R fire in Fire Zone 03-02, as the control cable for this breaker is routed through Fire Zone 03-02. In accordance with the applicable BFN Safe Shutdown Instruction, breaker 1848 is isolated and tripped locally prior to connecting Diesel Generator 3B to 4kV Shutdown Board 3EB. If offsite power was lost and 4kV Shutdown Board B and 4kV Shutdown Board 3EB were powered from Diesel Generators B and 3B respectively, and fire damage occurred to the breaker 1848 control cable and the cable for the breaker 1828 differential lockout contacts (which are both routed in Fire Zone 03-02) prior to the completion of Safe Shutdown Instruction steps to isolate and trip breaker 1848, then the potential to parallel Diesel Generators B and 3B out of phase would exist. Paralleling the Diesel Generators B and 3B out of phase with each other or offsite power poses the potential to damage either Diesel Generator.

"Therefore, this condition could result in a loss of power to credited safe shutdown equipment that would challenge the ability to provide adequate core cooling during performance of BFN Safe Shutdown Instructions.

"This condition is being reported pursuant to 10 CFR 50.72(b)(3)(ii)(B). This is also reportable as a 60-day written report in accordance with 10 CFR 50.73(a)(2)(ii)(B).

"The NRC Resident Inspector has been notified of this event."