The following information was provided by the State of
Ohio via email:
At 1530 EDT on 10/28/14, an INEOS Supervisor noticed that the indicator for the High-High Level gauge for the tank in the DIN1 reactor showed that the gauge was in the open position. The gauge shutter was closed immediately upon this discovery. The level gauge contains a 1 Ci Cs-137 source (assay date 1993).
The open shutter could have caused exposures to non-occupational workers who were working in the area performing cleaning and maintenance. The tank had been emptied for cleaning and contractors have been entering the tank for maintenance. Workers would have passed through the beam while using the access ladder to gain entry to the tank to perform their work. At the time of the original notification by the licensee, it was unknown how many individuals might have been exposed and for how long. The licensee was advised to take prompt action to determine the exposure to the individuals and it was recommended that he contact a CHP Health Physics Consultant as soon as possible.
ODH [Ohio Department of Health] responded on 10/29/14. Investigation determined that work actually began on 10/26/14 and that five (5) individuals were involved, all non-occupational workers. Any exposure would have been primarily from passing through beam on access ladder enroute to work in tank, which was taking place approximately 25 feet below the beam inside the tank. There was one (1) individual who was performing a maintenance task in or near the beam for approximately 15 minutes at a distance of approximately 12 inches from the gauge.
Licensee has contacted a local gauge manufacturer which has experienced staff available to assist with dose reconstruction.
Information on gauge and source model/type/serial number not available at time of this entry. More information to follow as available.
Initial investigation would indicate that exposures may exceed allowances for non-occupational workers, but not at a level that would result in serious health issues.
Ohio Item Number: OH140012