Conceptual Design of Temporally Storage Area in Hot Cell for Fusion DEMO Reactor

摘要

In the maintenance procedure of fusion DEMO reactor, used in-vessel components are removed from the reactor vessel to be replaced. The temporally storage area for the used blanket segments is necessary. In the present work, the temporally storage area is conceptually designed as the used segments are stored dispersively in the plural compartments in the hot cell for the following dismantling procedure. The space dose rate of the compartment, where more than one segment is installed, was evaluated by means of the gamma ray transport calculation with PHITS Monte Calro analysis code. The space dose rate in the compartment decreases with time. For example, by the temporally storage of five used segments in one compartment for 20 years, the space dose rate in the compartment becomes lower than 250 Gy/hr, which is the limited value proposed for the remote handling in the ITER. The decay heat of the segments during the temporally storage is removed by flowing He. The segments are cooled at the temperature lower than 550 ?C. Then, the used back plates can be reused in the other operation of the reactor, since the mechanical properties of the back plates are not affected by the heat treatment during the temporally storage.