ENS 44364
ENS Event | |
|---|---|
22:20 Jul 21, 2008 | |
| Title | Agreement State Report - Potential Occupational Overexposure |
| Event Description | On July 22, 2008, the State of Maryland was informed by the Teletherapy Operations Manager for Neutron Products, Inc. that one of their teletherapy service engineers performing an Alcyon Co-60 source exchange in Brazil had received a potential overexposure.
During the source exchange, the engineer's electronic dosimeter alarmed. Immediate actions were taken to properly secure the source. Preliminary dosimetry readings for the service engineer indicated a potential whole body exposure of approximately 5,211 mrem and extremity reading at the right wrist exceeding 10R (off scale high). The service engineer's film badge was sent for immediate processing to Global Dosimetry with expected results available for evaluation by Thursday, 7/24. The results from Global Dosimetry for the service engineer prior to the incident are as follows: Monthly whole body (DDE, mrem) - 13,465 + 92 (Jan. - May) = 13,557 Left wrist (SDE, mrem) - 73,356 + 236 (Jan. - May) = 73,592 Right wrist (SDE, mrem) - 746 + 488 (Jan. - May) = 1,234 Brazilian regulatory personnel were onsite at the hospital at the time the incident occurred and were briefed within one (1) hour by the service engineer.
Per our telephone conversation of today [between the state and the licensee], this is to update our initial verbal and written Twenty-Four Hour Notifications made July 22, 2008 regarding the incident in Sao Paulo, Brazil, and to summarize our employee's written account thereof. On July 21, 2008 at approximately 6:20 pm EDT, Neutron Products employee #502, informed us via telephone that he may have received an over-exposure while performing a source exchange on an Alcyon II teletherapy unit located in Sao Paulo, Brazil. On July 21, 2008, employee #502 and a radiation worker from Brazil were in the process of transferring the expended cobalt-60 source from the Alcyon II unit into Neutron's transfer cask in accordance with Specification P-9, Appendix XI. After engaging the source holder with the removal tool, #502 transferred the source holder from the Alcyon II unit head into the transfer cask. Once the source holder was in the transfer cask, #502 continued making preparations to complete the removal sequence. Employee #502 had completed all the steps of the removal sequence and was in the process of removing the removal tool from the transfer cask, when it was determined by audible alarms and before the tool was completely out of the cask, that the cobalt-60 source was still connected to the end of the removal tool. At that point, #502 reinserted the removal tool back into the cask and repeated the steps again to make sure that the Source was disengaged from the removal tool. Once he was sure that the source was no longer attached to the removal tool, the tool was removed from the cask, and all the covers installed. The transfer cask now contains both the expended and new sources. Immediately after the container was secured, both men read their SRD's and reported their dose as follows: #502: WB-5,211 mrem, Left Wrist-300 mrem, and Right Wrist-off Scale (10R dosimeter); Brazilian Worker: WB-533 mrem, Left Wrist-off scale (10R dosimeter), and, Right Wrist-4,100 mrem. The TLD's were sent via FED-EX to Global Dosimetry Solutions in Irvine, CA, for emergency reading and the results are as follows: #502: Monthly WB DDE-13,465 mrem, Quarterly WB DDE-11,126 mrem, Left Wrist SDE-73,356 mrem, and Right Wrist SDE-746 mrem. Brazilian Worker: Monthly WB DDE-702 mrem, Quarterly WB DDE-1,559 mrem, Left Wrist SDE-3,030 mrem, and Right Wrist SDE-8,542 mrem. Employee #502 will be returning home sometime this weekend. He will not be involved in any radiation work for the remainder of the year. Notified R1DO (Trapp) and FSME (M. Burgess) |
| Where | |
|---|---|
| Neutron Products Inc Dickerson, Maryland (NRC Region 1) | |
| License number: | MD-3102503 |
| Organization: | Maryland Dept Of The Environment |
| Reporting | |
| Agreement State | |
| Time - Person (Reporting Time:+84.62 h3.526 days <br />0.504 weeks <br />0.116 months <br />) | |
| Opened: | Alan Jacobson 10:57 Jul 25, 2008 |
| NRC Officer: | Jason Kozal |
| Last Updated: | Jul 28, 2008 |
| 44364 - NRC Website | |
Neutron Products Inc with Agreement State | |
WEEKMONTHYEARENS 443642008-07-21T22:20:00021 July 2008 22:20:00
[Table view]Agreement State Agreement State Report - Potential Occupational Overexposure 2008-07-21T22:20:00 | |