Lasers to aid Fukushima Daiichi fuel removal

20 July 2015

Laser technology for the removal of fuel debris from the damaged reactors at the Fukushima Daiichi nuclear power plant could be developed through a joint research agreement signed between three Japanese organizations.

The Japan Atomic Energy Agency (JAEA), Hitachi-GE Nuclear Energy and Sugino Machine signed the agreement on 15 July. Under the agreement, the three organizations will undertake basic research, applying their "mutually complementary" experience, to develop new laser technology, methods for in-reactor cutting and new ways for cutting thick steel plate. The aim of the research is for the possible application of laser technology in the retrieval of fuel debris during reactor decommissioning, such as at Fukushima Daiichi.

JAEA has already been investigating the use of remotely-controlled robots equipped with lasers for cutting steel plates up to 150mm thick in underwater environments during decommissioning of the 600 MWe demonstration Advanced Thermal Reactor (ATR) unit at Fugen, which shut down in 2003.

Based on the results work at Fugen and with the aim of applying laser technology at Fukushima Daiichi, JAEA said it has already begun a 'fusing and crushing' experiment using a mixture of metals and ceramics as dummy nuclear fuel debris.

Hitachi-GE has experience in the construction and operation of boiling water reactors and advanced boiling water reactors. It has also been developing technology for the decommissioning of the Fukushima Daiichi units.

Meanwhile, Sugino Machine - a supplier of water-jet cutting machinery - is also a designer and manufacturer of equipment for the maintenance of nuclear reactors. The company has also been working on the development of remotely-operated equipment and devices for use in radioactive environments.

Applying their respective experience, the organizations aim to develop remotely-controlled equipment that can be used in confined spaces to cut through thick steel plate and retrieve fuel debris. They will use JAEA's remote technology development centre - currently under construction at Naraha - to demonstrate the suitability of the technology at Fukushima Daiichi.

The contract will run until the end of March 2017.

Researched and written
by World Nuclear News