PNO-IV-96-064, on 961129,license Reviewer Indicating, Experiencing Problem W/Teletherapy Unit Electrical Sys. Technician Concluded,Loose Wire Connection Causing Circuit Interruption,Preventing Activation of Solenoid Connected
| ML20135E406 | |
| Person / Time | |
|---|---|
| Site: | 03022280 |
| Issue date: | 12/05/1996 |
| From: | Linda Howell, Wenslawski F NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| References | |
| PNO-IV-96-064, PNO-IV-96-64, NUDOCS 9612110243 | |
| Download: ML20135E406 (2) | |
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, December 5,1996 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNO-IV-96-064 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by Region IV staff in Arlington, Texas on this date.
Facility Licensee Emeroency Classification Department Of Veterans Affairs Notification of Unusual Event Va Medical Center-West Los Angeles Alert 11301 WILSHIRE BLVD.
Site Area Emergency Los Angeles, California 90073 General Emergency Dockets: 03022280 License No: 04-00181-12 X Not Applicable
Subject:
TELETHERAPY UNIT MALFUNCTION On November 29,1996, the licensee's teletherapy physicist telephoned the Region IV Walnut Creek Field Office (WCFO) and left a voice mail message for a license reviewer indicating that he was experiencing a problem with a teletherapy unit (AECL Theratron 780) electrical system. After receipt of the message on December 2 and several followup telephone calls, the following information was obtained.
On November 27,1996, a radiation therapy technologist noted that the cobalt-60 teletherapy source was not in the exposed (beam on) position during treatment of a patient. The treatment was terminated and subsequent evaluation of the control panel operation by the teletherapy physicist indicated sporadic failure of the source to move to the exposed position despite normal operation of the timer. Additional patients were apparently successfully treated on November 29 and December 2,1996. However, the unit continued to occasionally malfunction causing a beam off condition despite normal operation of the exposure timer.
On December 2,1996, a repair technician from Theratronics International Corporation arrived at the medical center and tested the teletherapy unit electrical system and source exposure mechanism. The technician concluded that a loose wire connection was causing a circuit interruption which in turn prevented the activation of a solenoid driver connected to the source drawer, preventing the source from moving to the exposed position. The control console lights were found to be functioning normally; however, the timer continued to count even though the source was not in the beam-on configuration. (The Theratronics technician noted that source position indiciators on the treatment unit console and outside the treatment room door did not activate when the source failed to move into the exposed position.) On December 4,1996, the technician informed the WCFO staff that he had repaired the loose wire and determined that the unit was fully operational.
9612110243 961205 PDR I&E PNO-IV-96-064 PDR c
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PNO-IV 96-064 The licensee is continuing to investigate the possibility that prior radiation therapy treatments may have been either interrupted or not given at all. At this point it is not known whether the situation has resulted in any misadministrations. Region IV staff has been in contact with the licensee and Theratronics concerning the possibility of a generic electrical problem and a possible 10 CFR Part 21 defect. Region IV has dispatched two senior materials inspectors from the WCFO to the licensee's facility. The FDA has also dispatched a representative (an electrical engineer) who will collaborate with the NRC inspectors in reviewing the problem with the teletherapy unit. The Theratronics technician will remain at the licensee's f acility for further followup with the NRC inspectors. The licensee has agreed to not use the unit pending review and approval by the NRC.
The state of California has been informed.
Region IV has informed NMSS.
This information herein has been discussed with the licensee and is current as of 4:00 p.m.,
PST, December 4,1996.
Contact:
Linda Howell Frank Wenslawski (817)860-8213 (510)975-0219