Beam physics design of a 30-MW beam transport to the target for an accelerator-driven subcritical system

Yee-Rendon, B. ; Meigo, Shinichiro   ; Kondo, Yasuhiro   ; Tamura, Jun  ; Nakano, Keita   ; Maekawa, Fujio  ; Iwamoto, Hiroki   ; Sugawara, Takanori  ; Nishihara, Kenji  

To reduce the hazard of minor actinides in nuclear waste, JAEA proposed an accelerator-driven subcritical system (JAEA-ADS). The JAEA-ADS drives a subcritical reactor 800-MWth by 30-MW proton linac delivering the beam to the spallation neutron target inside the reactor. The beam transport to the target (BTT) is required for high-beam power stability and low peak density to ensure the integrity of the beam window. Additionally, the design should have compatible with the reactor design for the maintenance and replacement of the fuel and the beam window. A robust-compact BTT design was developed through massive multiparticle simulations. The beam optics was optimized to guarantee beam window feasibility requirements by providing a low peak density of less than 0.3 A/mm. Beam stability was evaluated and improved by simultaneously applying the linac's input beam and element errors. The input beam errors to the reactor were based on the beam degradation obtained by implementing fast fault compensation in the linac. Those results show that the BTT fulfills the requirements for JAEA-ADS.