Design study of graphite moderated gas-cooled high flux reactor

Abstract A feasibility design study of the graphite moderated gas-cooled reactor as a high flux reactor has been performed. The core of the reactor is equipped with two graphite reflectors, i.e. the inner reflector and the outer reflector. The highest value of the thermal neutron flux is expected to be achieved in the inner reflector region, and a moderately high thermal neutron flux is also expected to be obtained in the outer reflector region. By choosing optimal values of the core-reflector geometrical parameters and moderator-to-fuel atomic density, a high thermal neutron flux can be obtained. Because of the thermal design constraint, however, this design will produce a relatively large core volume (about 10 7 cm 3 ) and consequently a higher reactor power (100 MWth). Preliminary calculational results show that with an average power density of 10 W/cm 3 , a maximum thermal neutron flux of 10 15 cm −2 s −1 can be achieved in the inner reflector.