Manufacture of a High Temperature Neutron Flux Detector for Generation IV Reactors

Abstract

Ultra have designed and manufactured a fission chamber for safety critical neutron flux detection that can be used in Generation IV high temperature nuclear reactors. The design is a cylindrical device made from materials compatible with the hostile environments expected in next generation reactors. The functional characteristics of the detector are based on an existing high temperature stainless steel detector manufactured by Ultra for the UK AGR fleet, which are used in pulse and Campbell modes.

The detector functional performance has been fully characterised in pulse, Campbell and DC modes at fluxes up to 1×10⁷ nv (neutrons/cm²/s) at room temperature. The pulse mode response in low neutron fluxes has been determined from room temperature up to 800 °C, whilst both Campbell and DC mode performance has been determined at room temperature.

Test results demonstrate stability of the output regardless of the temperature at which the detector has been tested, indicating that the detector design is suitable for use in service in anticipated Generation IV reactor environments.