A new detector to measure gamma and beta decay power from radionuclides

Neutron activation of structural materials gives rise to an energy release during the subsequent radioactive decay. In large devices for energy produc tion like a fission reactor, the future proposed Energy Amplifier or a Fusi on power plant, this energy release represents a source of heat, which alth ough at a very much lower level than the heating during operations is of th e order of MWs for large nuclear power plants. Accurate estimation of the d ecay power is essential for safety analyses of the power plant against loss of coolant accidents, etc. Some computer codes have been developed to pred ict the decay power, but validation of the computer codes through experimen tal measurements is essential. A new large, almost 4 pi detector, formed by coupling a well-type CsI scintillator and a small plastic beta detector ha s been developed for accurate and efficient measurements of decay power fro m gamma and beta radiation. preliminary measurements of decay power produce d in neutron-activated tungsten are presented and compared with the predict ions of the European Activation Code System, EASY-99. (C) 2001 Elsevier Sci ence B.V. All rights reserved.