抄録
Development of damaged fuel debris cutting technique in Fukushima Daiichi nuclear plant is one of the important issues for the defueling operations such as removing from the reactor, handling and storage, and so on. Previous knowledge in the Three Mile Island Unit 2 (TMI-2) nuclear plant accident is reported that fuel debris was made of uranium oxides, stainless steel, zircaloy and so on. Therefore, it is difficult to cut fuel debris by machine processing. Laser cutting is convenient to cut complex materials. However, it is difficult to know the thickness of fuel debris in advance, so it is hard to apply the conventional laser cutting method. In this study, we have been developed the cutting technique for fuel debris by using laser gouging method. Test pieces that simulate fuel debris ware fabricated by embedding ceramic pellet on stainless steel. Laser gouging test was performed by cutting surface of the test pieces with high power fiber laser, whose maximum irradiation power was 10kW. According to the test result, laser gouging process has the ability to grind the simulated fuel debris under atmospheric condition. In addition, same kind of cutting effect could be performed underwater.
