Handling manipulator device in nuclear reactor and radiation-degradation analysis method

The present invention concerns a radiation-degradation analyzing method in which remaining life of an underwater device main body is forecast by using a robot device operated in a nuclear reactor based on radiation dose. The underwater device main body comprising a TV camera for visual inspection for the reactor and a propulsion device is controlled by way of cables. Information for depth obtained from a depth gauge and dose rate distribution in the reactor are read successively into a memory of a computer in a calculation device for processing signals sent from the underwater device main body. Values of forecast radiation dose given to the underwater device main body till it is recovered is calculated, and forecast dose rate values are further added thereto forecast dose rate thereby forecasting remaining lifetime of parts relevant to the underwater device main body during operation. (N.H.)