An assessment of the base blanket for ITER

Ideally, the ITER (International Thermonuclear Experimental Reactor) base blanket would provide the necessary tritium for the reactor to be self-sufficient during operation, while having minimal impact on the overall reactor cost, reliability, and safety. A solid breeder blanket was developed in the CDA phase in an attempt to achieve such objectives. The reference solid breeder base blanket configurations at the end of the CDA phase have many attractive features such as a tritium breeding ratio (TBR) of 0.8-0.9 and a reasonably low tritium inventory. However, some concerns regarding the risk, cost, and benefit of the base blanket were raised. These include uncertainties associated with the solid breeder thermal control and the potentially high cost of the amount of Be used to achieve high TBR and to provide the necessary thermal barrier between the high-temperature solid breeder and low-temperature coolant. The basis for the selection of a breeding blanket is discussed in light of the incremental risk, cost, and benefits relative to a nonbreeding blanket. Key issues associated with the CDA breeding blanket configurations are analyzed. Alternative schemes that could enhance the attractiveness and flexibility of a breeding blanket are explored