Conceptual study for the hollow core of a research reactor

Komeda, Masao   ; Arai, Masaji ; Sagawa, Hisashi; Kusunoki, Tsuyoshi 

We carried out conceptual study of a future research reactor focused on a hollow core. The hollow core satisfied both utilizations of neutron beam and irradiation. It was indicated that the hollow core with 40.8cm-by-40.8cm had higher neutron flux in the DO tank by 30% than a square core with 40.8cm-by-40.8cm. The hollow core could achieve almost same flux as a smaller square core with 35.7cm-by-35.7cm. Because there was the peak flux at the furthest point from the core in the DO tank in the case of the hollow core, it was able to obtain more neutrons for neutron irradiation utilization. The hollow core had flat and large (20.4cm-by-20.4cm) irradiation area of fast neutron in the central area. There the fast neutron flux was 7.010 (n/cm/s). There is not a reactor that has such a large irradiation field of fast neutron. Therefore the hollow core is regarded as an attractive research reactor for irradiation field of fast neutron.