Thorium-loaded low-power reactor installation operated with super-long fuel residence time

摘要

It was established in numerical experiments conducted at the Institute for Safety Research and Reactor Technologies (ISR-2) of the research center Forschungszentrum Jülich (1998–1999) that thorium-plutonium fuel composition ensures due to the presence of anomaly in the dependence of resonance neutron absorption on the ratio of moderator volume to fuel volume the possibility to organize super-long duration of fuel residence in the cores of VVER-type reactors. Such possibility was demonstrated in the present study for high-temperature thorium-loaded reactor installation with 60 MW power. In this case the ratio of moderator volume to the volume of resonance absorber in the reactor core is within the interval of (45–60). It is specifically such type of low-power reactor installations that may constitute the basis of regional power generation in Russia. The purpose of the study was to investigate the neutronics characteristics of thorium-loaded low-power reactor installation with fuel blocks and fuel pellets with different configurations in order to select the reactor core design and the core fuel load ensuring optimal utilization of thorium in it and obtaining maximum possible generation of energy in the course of super-long fuel residence in the core. Implemented studies and numerical experiments were performed using verified computation codes included in the MCU5 and WIMSD5B software packages, updated libraries of evaluated nuclear data (ENDF/B-VII.0, JEFF-3.1.1, JENDL-4.0, ROSFOND, BROND, ABBA and others) and multi-group approximations. It was established that thorium-loaded reactor installation with suggested design is the installation operated with fast and intermediate neutrons. Results of calculation allow making the conclusion that reactor installation with suggested configuration of the fuel block and the fuel pellet, as well as with the fuel composition in question can be operated during not less than 3500 effective days at the power level of 60 MW without reloading.