[en] Purpose: To enable to attain the operation on a cylindrical coordinate system thereby performing dismantling operation exactly and at a high reliability. Constitution: A reactor dismantling robot is suspended by ropes by an elevating device to the inside of reactor shielding walls. The robot has a fixed portion having a plurality of legs abutting against the inner surface of the shieling walls while extending and shrinking radially in the horizontal direction and an arm portion having an operation arm disposed with a shielding wall breaking operation device. The arm portion is disposed with a mechanism for vertically moving the operation arm and a mechanism for forwarding and backwarding the operation arm in the horizontal direction and the arm portion itself is constituted so as to be rotatable around a vertical axis. (Seki, T.)

No abstract available

[en] For isotropic graphite, SiC converted graphite and B₄C converted graphite, the conditions of baking and He ion impact for the reduction of retained hydrogens are discussed based on a hydrogen desorption model. For this purpose, the existing data concerning the hydrogen retention and the helium ion irradiation are employed. It is seen that the hydrogen trapped in form of C-H or Si-H bonding can not be desorbed by baking alone. Thus, the He discharge cleaning has to be applied for C-H and Si-H bondings. The hydrogen trapped in form of B-H bonding is very easily desorbed by baking alone with temperature of only 300degC. (author)