Event Notification Report for June 23, 2001

POWER LOST TO BUILDING BEACON CRITICALITY ACCIDENT ALARM SYSTEM (CAAS).

At 0350 hours on 06/23/01, it was discovered that the CAAS beacons for building C-333 were inoperable due to a loss of power. The system is required to be operable according to TSR 2.4.4.2.b for the prescribed modes of operation. Loss of power to the CAAS beacons occurred during the process of returning auxiliary power transformers to service. Power to the beacons was lost for a total of approximately 3 minutes. Normal power was subsequently restored. The building CAAS detectability and horn audibility were not lost due to the power failure. No operations were taking place in building C-333 while the CAAS beacons were inoperable but fissile material is stored in the building.

The NRC Resident Inspector has been notified of this event by the certificate holder.

* * * RETRACTED AT 1630 EDT ON 7/9/2001 BY J. M. UNDERWOOD TO FANGIE JONES * * *

The following is taken from a faxed report:

"The PSS's reporting determination was based on the fact that the CAAS lights are mentioned in the CAAS TSR 2.4.4.2b Basis Statement. The Basis includes a paragraph that describes the quarterly surveillance of the CAAS building horns and, in this paragraph, states that the test signal activates the high radiation light and bell in C-300 and activates the building CAAS horns and lights. This is the only mention of CAAS lights in the CAAS TSR. This statement has been interpreted in the past as requiring the CAAS lights to be available and operable and, when inoperable, requiring completion of the TSR 2.4.4.2b LCO actions and reporting to the NRC per 10CFR76.120 (c)(2).

"Since the subject event, NRA has reviewed the TSR, SAR. ANSI/ANS8.3, and 10CFR76 and noted the following:
[1] CAAS TSR 2.4.4.2b requires the CAAS to be operable (audible) and prescribes the required actions to be taken when the 'area does not have an audible criticality accident alarm'. Audibility is proven by the building CAAS horns which were not affected by the subject power failure. There are no actions required for loss of the building lights.
[2] Surveillance requirements 2.4.4.2b-1 and 2.4.4.2b-2 requires quarterly testing of the CAAS horns and verification that the CAAS air accumulator supply pressure to the building horns is adequate to sound the horns for at least 120 seconds. There are no TSR surveillance requirements for the building lights.
[3] ANSI/ANS8.3, 'Criticality Accident Alarm System'. Section 4.3 requires audio alarm signals and Section 6.4 requires periodic tests of the signals. ANSI/ANS8.3 does not require or recommend visual alarm signals except in Section 4.3.8, where visual signals are recommended in areas of very high audio background or mandatory hearing protection, neither of which applies to areas outside the buildings with CAAS coverage.
[4] PGDP SAR Section 5.2.2.4 states, 'a CAAS is provided to alert personnel if a criticality accident should occur. The system utilizes a distinctive audible signal to notify personnel in the affected area and initiate evacuation...'. There is no mention of the building lights.
[5] 10CFR76.89, Criticality Accident Requirements, requires USEC to maintain and operate a criticality monitoring and audible alarm system. There is no mention of building lights,

"From the information provided, NRA has concluded that CAAS audibility is provided solely by the CAAS horns and is not affected by the loss of the CAAS lights. Thus, the CAAS building lights are not required to be available and operable by the TSR and CAAS operability is not affected when the lights are not functional. Since the lights are not required to be available and operable by the TSR, the reporting requirement of 10CFR76.120 (c)(2) is not met and reporting is not required. In addition, the TSR LCD actions prescribed by TSR 2.4.4.2b do not apply to the CAAS lights and are not required to be implemented. Based on this information, the subject NRC event notification (PAD.01-023) is being retracted."

The licensee notified the NRC Resident Inspector. The R3DO (David Hills) and the NMSS EO (Eric Leeds) have been notified.

MAIN GENERATOR OVERCURRENT TRIP CAUSES REACTOR TRIP


Main Generator overcurrent trip caused a Main Turbine trip/Reactor trip. All rods fully inserted into the core. Both Motor Driven Auxiliary Feedwater Pumps automatically started and are currently maintaining proper steam generator water levels. Reactor Coolant System is being maintained at Normal Operating Temperature and Pressure via the stream dumps to the main condenser. First out annunciator was "2A" low low Steam Generator Water level. Plant computer printout indicated that the initiating event was a Main Generator Overcurrent Trip. No work was being performed on the Main Generator when the overcurrent trip occurred. All Emergency Core Cooling Systems and the Emergency Diesel Generators are fully operable if needed. The electrical grid is stable.

The NRC Resident Inspector was notified of this event by the licensee.