Neutronics design for power flattening of accelerator-driven system
Iwanaga, Kohei; Nishihara, Kenji
; Tsujimoto, Kazufumi
; Kurata, Yuji; Oigawa, Hiroyuki 
Japan Atomic Energy Agency (JAEA) promotes research and development of Accelerator-Driven system (ADS) to reduce the burden for conditioning and disposal of the high level radioactive waste by transmuting minor actinide (MA). In the present neutronics design, we investigated several methods to reduce the power peak, and showed the reduction of the temperature of cladding tubes and influence to the beam current. These methods are adjustment of inert matrix content in fuel in each burn-up cycle, multi-region design in terms of plutonium enrichment, pin radius and inert matrix content, modification of the level of the beam window position and height of the central fuel assemblies. As the result, the maximum temperature at the surface of fuel cladding tubes can be reduced by 110
C by combining the adjustment of inert matrix content in each burn-up cycle and multi-regin design in terms of pin radius or inert matrix content.