Conceptual design and safety characteristics of a new multi-mission high flux research reactor

Research reactors with neutron fluxes higher than 10 14 n cm −2 s −1 are widely used in nuclear fuel and material irradiation, neutron-based scientific research, and medical and industrial isotope production. Such high flux research reactors are not only important scientific research facilities for the development of nuclear energy but also represent the national comprehensive technical capability. China has several high flux research reactors that do not satisfy the requirements of nuclear energy development. A high flux research reactor has the following features: a compact core arrangement, high power density, plate-type fuel elements, a short refueling cycle, and high coolant velocity in the core. These characteristics make it difficult to simultaneously realize high neutron flux and optimal safety margin. A new multi-mission high flux research reactor was designed by the Institute of Nuclear and New Energy Technology at Tsinghua University in China; the reactor can simultaneously realize an average neutron flux higher than 2.0 × 10 15 n cm −2 s −1 and fulfill the current safety criterion. This high flux research reactor features advanced design concepts and has sufficient safety margins according to the preliminary safety analysis. Based on the analysis of the station blackout accident, loss of coolant accident, and reactivity accident of a single-control drum rotating out accidently, the maximum temperature of the cladding surface, minimum departure from nucleate boiling ratio, and temperature difference to the onset of nucleate boiling temperature satisfy the design limits.