Evaluation of personal dosimeters and electronic modules under high-dose field

Described in this report are evaluation tests of neutron-induced malfunction of real-time personal dosimeters and electronic modules using the Transient Experiments Criticality Facility, TRACY, at the Japan Atomic Energy Agency. In the event of radiological or nuclear terrorism, radiation levels are expected to be high, especially if nuclear-critical devices are used. In such devices, fission chain reactions develop that may lead to nuclear criticality with strong lethal emissions of both neutrons and gamma-rays. A wide area of radius 400m at least should be cordoned off. In such a situation real-time dosimeters with wireless data transmission capability would provide essential support for first-response teams. The reliability of these apparatuses, however, has not been evaluated sufficiently under such high-dose conditions. We have evaluated these at TRACY, which is a reactor that can realize controlled nuclear excursions using 10% ²³⁵U-enriched uranyl nitrate solutions as fuel.