 INES 2 |
Internal Exposure |
On December 2, 2004, the State of Texas notified the NRC that a licensee had breached an Americium-241/Beryllium sealed neutron source containing approximately 1.85 GBq (50 mCi). The device that contained the source was used to measure water salinity. The source was housed in an aluminum tube (approximately 3.8 cm in diameter by 20.3 cm in length) that also contained a neutron detector. In preparation for disposal, the licensee used a band saw to separate the neutron detector and the aluminum tube from the source and inadvertently cut through the sealed source encapsulation.
Two individuals, a saw operator and a health physics technician, were involved in removing the source and a third individual was located approximately 1.3 meters from the saw. All three individuals were surveyed, clothed in personal protective equipment and taken to the hot lab shower where nasal smears were taken for intake analysis. Each individual took a shower to remove residual contamination and were subsequently allowed to go home. Wipe assays concluded that two individual smear samples indicated the presence of 3.7-7.4 Bq (0.1- 0.2 mCi).
The individuals were also scheduled to receive a whole body count.
On March 25, 2005, the State of Texas provided the NRC with an update regarding the ongoing decontamination of the facility. Most equipment had been decontaminated and/or removed for disposal. In addition, there was no contamination outside of the shop area and continuous air monitoring concluded that the airborne concentration was below regulatory limits.
On May 6, 2005, the State of Texas notified the NRC that based on a consultant’s preliminary analysis, the saw operator may have received a committed effective dose equivalent (CEDE) of 107 mSv (10.7 rem) and the health physics technician may have received a CEDE of 58.2 mSv (5.82 rem).
The State of Texas will provide the NRC an update upon their review of the internal dosimetry analysis.
Event date: Wed, 01-12-2004
