Neutronic analysis of beam window and LBE of an Accelerator-Driven System

Nakano, Keita   ; Iwamoto, Hiroki   ; Nishihara, Kenji  ; Meigo, Shinichiro   ; Sugawara, Takanori  ; Iwamoto, Yosuke   ; Takeshita, Hayato*; Maekawa, Fujio  

Neutronic analysis of beam window of the Accelerator-Driven System (ADS) proposed by Japan Atomic Energy Agency (JAEA) has been conducted using PHITS and DCHAIN-PHITS codes. We investigate gas production of hydrogen and helium isotopes in the beam window, displacement per atom of beam window material, and heat generation in the beam window. In addition, distributions of produced nuclides, heat density, and activity are derived. It was found that at the maximum 12500 appm H production, 1800 appm He production, and damage of 62.1 DPA occurred in the beam window by the ADS operation. On the other hand, the maximum heat generation in the beam window was 374 W/cm. In the analysis of LBE, Bi and Po were found to be the dominant nuclides in decay heat and radioactivity. Furthermore, the heat generation in the LBE by the proton beam was maximum around 5 cm downstream of the beam window, which was 945 W/cm.