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Event Notification Report for July 20, 2009

U.S. Nuclear Regulatory Commission
Operations Center

Event Reports For
07/17/2009 - 07/20/2009

** EVENT NUMBERS **


45184 45210

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Hospital Event Number: 45184
Rep Org: GAMMA KNIFE CENTER OF THE PACIFIC
Licensee: GAMMA KNIFE CENTER OF THE PACIFIC
Region: 4
City: HONOLULU State: HI
County:
License #: 53-1196602
Agreement: N
Docket:
NRC Notified By: RONALD FRICK
HQ OPS Officer: DONALD NORWOOD
Notification Date: 07/03/2009
Notification Time: 18:42 [ET]
Event Date: 07/02/2009
Event Time: 14:00 [HST]
Last Update Date: 07/17/2009
Emergency Class: NON EMERGENCY
10 CFR Section:
35.3045(a)(3) - DOSE TO OTHER SITE > SPECIFIED LIMITS
Person (Organization):
GREG PICK (R4DO)
DUNCAN WHITE (FSME)

Event Text

MEDICAL EVENT - GAMMA KNIFE MISADMINISTRATION

A gamma knife treatment was prescribed for a patient being treated for multiple brain metastatic sites using an 8 mm collimator. The prescribed dose was 24 gray. The treatment was prescribed for 7 discrete sites in the brain. After the second discrete site had been treated it was found that an 18 mm collimator was being used to administer the treatment instead of the prescribed 8mm collimator.

After discovery, the collimator was changed to the 8 mm collimator. Treatment to the remaining 5 discrete sites was administered with the 8 mm collimator.

Both the patient and the patient's physician were notified of the use of the wrong collimator. The licensee states that there should be no clinical effects to the patient as a result of this misadministration.

The previous patient had been treated using the 18 mm collimator as the prescribed collimator.

Investigation into this event is continuing and a written report will follow.

In an effort to prevent recurrence, the licensee will send a notice to all authorized users, neurosurgeons and medical physicists that they should each independently check collimator size before each treatment is started.

A Medical Event may indicate potential problems in a medical facility's use of radioactive materials. It does not necessarily result in harm to the patient.

* * * UPDATE AT 1551 ON 7/17/2009 FROM RONALD FRICK TO MARK ABRAMOVITZ * * *

"The use of the 18 mm collimator instead of the 8 mm collimator increased the treatment site dose by 3%. The larger collimator caused the volume of each of the two treatment areas to increase by 2.35 cm3 [cubic centimeters]. This additional tissue received a dose of 24 Gy. If the correct collimator had been used, this tissue would have received a dose of approximately 4.3 Gy."

Both the physician and patient have been notified by the licensee.

Notified the R4DO (Gaddy) and FSME (Reis).

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Power Reactor Event Number: 45210
Facility: WATTS BAR
Region: 2 State: TN
Unit: [1] [ ] [ ]
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: GREG EVANS
HQ OPS Officer: BILL HUFFMAN
Notification Date: 07/18/2009
Notification Time: 00:26 [ET]
Event Date: 07/17/2009
Event Time: 17:42 [EDT]
Last Update Date: 07/18/2009
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION
Person (Organization):
KATHLEEN O'DONOHUE (R2DO)

Unit SCRAM Code RX CRIT Initial PWR Initial RX Mode Current PWR Current RX Mode
1 N Y 100 Power Operation 100 Power Operation

Event Text

ACTUATION OF EMERGENCY DIESEL GENERATORS DUE TO LOSS OF POWER TO SAFETY RELATED BUS

"At 1742 EDT on July 17, 2009, while attempting to restore normal alignment providing offsite power following repair of the 'D' Common Station Service Transformer (CSST), the transfer from the alternate to the normal power supply for the 6.9kV Shutdown Board 2B-B failed because of an apparent failure of the interlock that should have prevented closing the normal breaker until an undervoltage condition existed on the alternate feed. The emergency diesel generators received a blackout signal and all four diesel generators started. Loads transferred and shed properly, and all systems functioned as expected.

"WBN [Watts Bar Nuclear] had been in LCO 3.8.1 condition A since 0032 EDT on July 16, 2009 due to the outage of the D CSST. Because loads did not transfer to the offsite power source, WBN remains in LCO 3.8.1 A which requires restoration of the offsite power supply by 0032 EDT 7/19/2009.

"All systems are operating properly and the plant is stable. Troubleshooting and maintenance has begun and WBN anticipates return of the normal offsite power supply to the 2B-B Shutdown Board within the time required by technical specifications.

"This event is reportable under 10 CFR 50.72(b)(3)(iv) as an event or condition that resulted in valid actuation of the emergency diesel generators.

"The licensee has notified the NRC Resident Inspector"

The 6.9kV Shutdown boards at Watts Bar are safety related busses. The electrical configuration prior to the event had the 1A-A and 2A-A Shutdown Boards aligned to their normal offsite power source. The 1B-B and 2B-B Shutdown Boards were aligned to an alternate offsite power source because their normal source, the 'D' CSST had been out of service for repairs. Following completion of the repairs to the 'D' CSST, the licensee attempted to restore normal offsite power to the 2B-B Shutdown Board from the 'D' CSST using a fast transfer from the alternate power supply. For unknown reasons, the normal supply breaker attempted to close onto the 2B-B bus before the alternate supply breaker had opened. This, in effect, would have paralled both the primary and alternate sources of power to the 2B-B bus. An interlock prevents paralleling these two sources and resulting in both supply breakers tripping and the bus being de-energized. This generated a blackout signal that started all four emergency diesels generators (EDGs).

All the EDGs started as required, only the 2B-B loaded onto its associated shutdown bus, as expected, because of the bus had been de-energized. The other busses (1A-A, 1B-B, and 2A-A) remained energized and the associated EDGs did not load. The 1A-A, 1B-B, and 2A-A EDGs were shutdown and returned to a standby condition. The 2B-B EDG continued to power the 2B-B Shutdown Board while the licensee investigated the fast transfer problem.

All systems functioned as required during this event except for the 2B-B fast bus transfer from the alternate to normal offsite power supply.

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