Investigation of the irradiation method for 12 inch NTD silicon in JRR-3 (Contract research)

Komeda, Masao   ; Yamamoto, Kazuyoshi ; Yagi, Masahiro ; Sagawa, Hisashi

We investigated the irradiation method to irradiate 12 inch NTD silicon uniformly in JRR-3, where 6 inch NTD silicon is being irradiated at present, by using MVP of the Monte Carlo calculation code. In the case of irradiating 12 inch NTD silicon, the deviation of the doping distribution in the radial direction becomes 1.17 by the same irradiation method of 6 inch NTD silicon. Therefore the thermal neutron filter was introduced for uniform doping (the deviation is less than 1.10) in the radial direction and the effect was analyzed. As the result, it was indicated that the deviation of the doping distribution in the radial direction became less than 1.1 by using the neutron filter, which was made from aluminum alloy of 2 mm thickness including natural boron of 1%.