ENS 44110
ENS Event | |
|---|---|
07:00 Mar 28, 2008 | |
| Title | Agreement State Report Involving a Partial Equipment Failure of an Hdr Unit During a Source Exchange |
| Event Description | The following information was received from the State of Washington via email (quotations omitted for ease of reading):
STATUS: New Licensee: Providence Everett Medical Center City and State: Everett, WA License Number: WN-M0135-1 Type of License: Medical Date and time of Event: 28 March 2008 Location of Event: Everett, WA ABSTRACT: (where, when, how, why; cause, contributing factors, corrective actions, consequences, Dept. of Health (DOH) on-site investigation; media attention): A Varian Medical Systems (varian) representative was attempting a routine source exchange at the licensee's facility. There were no patients or Medical Center staff involved in the source exchange process. The varian rep noted some trouble with making the "old" source enter the exchange container. After several attempts the rep realized the transfer was not proceeding as expected. The rep telephoned staff at Varian Corporate headquarters for assistance. The decision was made to cut the source wire near the source and place the source assembly into the emergency shielded source container (emergency pig). After the wire was snipped and the cut piece placed into the emergency pig, the rep performed a survey and noticed that the radiation levels were less than expected. At this time the licensee and the Varian rep both notified the Office of Radiation Protection of the event by telephone. The room was locked and barrier tape placed across the door. A Varian recovery team was called for and arrived at the Medical Center, with the source designer, on Saturday, 29 March 2008. An Office of Radiation Protection investigator also joined the team on Saturday to direct the onsite investigation and recovery. The investigation determined that both the dummy wire and the source wire had tried to exit the HDR unit simultaneously. The wires become stuck in the "home switch" part of the HDR. When a wire was cut it had been the dummy wire and not the source assembly wire. The cutoff dummy wire had been placed into the emergency pig which had given lower then the expected dose rate readings. On Saturday, the recovery team successfully retracted the source into the HDR. Testing is underway to determine why the HDR source exchange process had allowed both wires to be sent out at once. A comprehensive written report is expected from the manufacturer within the next few days. Notification Reporting Criteria: WAC 246-220-250 Equipment Failure. Isotope and Activity involved: HDR Sealed Source: Ir-192, approximately 185 GBq (5 Curies). Overexposures? (number of workers/members of the public; dose estimate; body part receiving dose; consequence): None Lost, Stolen or Damaged? (mfg., model, serial number): Varian HDR source model VS2000 (not lost, not stolen, possibly damaged). Disposition/recovery: Source recovered 29 March 2008 by Varian recovery team. Leak test? No "official" leak test yet but several contamination wipe surveys were performed during the course of the recovery. All of these were negative. Vehicle: N/A Release of activity? None Activity and pharmaceutical compound intended: N/A Misadministered activity and/or compound received: N/A Device (HDR, etc.) Mfg., Model; Varian VariSource Ix (Trademark) HDR Exposure (intended/actual); consequences: None to patients and the public. The highest exposure received by a recovery team member was 87 mRem. Was patient or responsible relative notified? N/A Was written report provided to patient? N/A Was referring physician notified? N/A Consultant used? No Event Report # WA-08-020.
A written report was received [by the state] from the manufacturer. The Varian report concluded the cause of the incident was 'the service engineer mistakenly extending the active source wire while the dummy wire was already in the same pathway. This action jammed the dummy and source wires at the home switch and prevented the active wire from properly retracting to the tungsten safe when commanded.' [The manufacturer] also concluded the likelihood of a licensee / operator recreating this type of event was nil, since the conditions which allowed this to happen are only present when the factory service engineer is working on the unit. This was originally reported as an equipment failure but now appears to be an error by the manufacturer's representative. Notified R4DO (Clark) and FSME (Von Till). |
| Where | |
|---|---|
| Providence Everett Medical Center Everett, Washington (NRC Region 4) | |
| License number: | WN-M0135-1 |
| Organization: | Wa Division Of Radiation Protection |
| Reporting | |
| Agreement State | |
| Time - Person (Reporting Time:+83.32 h3.472 days <br />0.496 weeks <br />0.114 months <br />) | |
| Opened: | Arden C. Scroggs 18:19 Mar 31, 2008 |
| NRC Officer: | Steve Sandin |
| Last Updated: | Apr 18, 2008 |
| 44110 - NRC Website | |
Providence Everett Medical Center with Agreement State | |
WEEKMONTHYEARENS 441102008-03-28T07:00:00028 March 2008 07:00:00
[Table view]Agreement State Agreement State Report Involving a Partial Equipment Failure of an Hdr Unit During a Source Exchange 2008-03-28T07:00:00 | |