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Full-scale model used to test decommissioning for Fukushima reactor

A test using a model of the No. 2 reactor’s suppression chamber and torus room at the Fukushima No. 1 plant is demonstrated for media in Naraha, Fukushima Prefecture, on Tuesday.

NARAHA, FUKUSHIMA PREF. – A research institute used a full-size mock-up of part of a nuclear reactor on Tuesday to conduct trial decommissioning experiments for use on the disaster-hit Fukushima No. 1 plant.

The International Research Institute for Nuclear Decommissioning (IRID) carried out the experiments using a 20-meter wide, 12-meter high model of the No. 2 reactor’s suppression chamber and torus room — areas located below the reactor’s containment vessel.

IRID was established in 2013 by nuclear plant makers, power firms and government organizations to develop technology needed for the decommissioning of the Fukushima plant, which was damaged by the March 3, 2011 earthquake and tsunami. After the disaster, three of the plant’s reactors suffered meltdowns in the world’s most severe nuclear crisis since the 1986 Chernobyl disaster.

The model is located at the Naraha Remote Technology Development Center, near the crippled Fukushima No. 1 plant.

“We would like to continue testing until next summer, approximately, and use (the outcomes) in deciding methods to retrieve fuel debris,” Atsufumi Yoshizawa, IRID executive director, said.

Removing nuclear fuel debris is perceived as one of the most difficult challenges in the decommissioning process.

With radiation emitting from the debris, a method is under consideration to fill containment vessels at the plant with water and remove debris from the top of the vessels, using the water to provide some protection from the harmful radiation.

Challenges in implementing this method include how to prevent contaminated water leaking from cracks in the vessels.

During Tuesday’s experiments, which were open to the media, workers wearing protective suits and masks attempted to insert a hose into the torus room mock-up while using remote cameras to observe their work.

A further experiment to stop water leaking from a suppression chamber is planned.

http://www.japantimes.co.jp/news/2016/11/29/national/full-scale-model-used-test-decommissioning-fukushima-reactor/#.WD5pUlzia-d

December 1, 2016 - Posted by dunrenard | Fukushima 2016 | decommissioning, Experiments, Fukushima Daiichi