DOSE RATE MEASUREMENT OF UNIVERSITY OF VIRGINIA REACTOR FUEL ELEMENTS

In order to comply with Nuclear Regulatory Commission regulations, all highly enriched reactor fuel possessed by any facility in excess of five kilograms of uranium-235 must be self protecting i.e. emitting radiation in excess of 100 Rem per hour at three feet in air. A methodology has been developed to measure the dose rate from University of Virginia reactor fuel elements both in-air and underwater. Actual measurements indicate that multiple measurements made in-water may be used to characterize the decay of these elements and convert dose rates obtained underwater to what they would be at three feet in-air. The ability to make the determination of the in-air dose rate without actually making an in-air measurement greatly simplifies compliance with the NRC regulations.