Editer l'article Suivre ce blog Administration + Créer mon blog
Le blog de fukushima-is-still-news

information about Fukushima published in English in Japanese media info publiée en anglais dans la presse japonaise

Don't even know where melted fuel is...



June 11, 2013


Status of melted fuel in Fukushima reactors uncertain despite push for early removal



Uncertainty over the location of melted fuel inside the crisis-hit Fukushima No. 1 Nuclear Power Plant continues to cast a shadow over plans to remove the fuel at an early date, as envisaged in a draft version of a revised road map for decommissioning the plants' reactors.

A draft announced by the government and Tokyo Electric Power Co. (TEPCO) on June 10 outlines plans to start removing the melted fuel about 18 months earlier than originally forecast. But the proposed length of time it will take to decommission the reactors has been left unchanged at "30 to 40 years."

Reactor Nos. 1-3 at the plant contained a total of 1,496 rods of nuclear fuel in their cores. Another 3,106 rods of spent fuel are stored in the pools of the No. 1-4 reactors. The melted fuel inside the reactors has been labeled "debris," and is believed to have hardened after mixing with metal and other substances. Each fuel rod weighs about 300 kilograms, and a high level of technical expertise would be required when undertaking a remote control operation to cut up and retrieve clumps of scattered radioactive materials weighing a combined 450 tons or thereabouts.

The bid to remove the melted fuel earlier than planned hinges on whether workers can succeed in filling the reactor cores with water. This method to screen off radiation was used in the Three Mile Island accident that occurred in 1979. However, the cores of reactors at the Fukushima plant have holes, and the task at hand is finding which parts have been damaged and repairing them.

It took about six years before fuel began to be removed in the Three Mile Island accident, but in Fukushima, even if the melted fuel is removed earlier than planned, the work won't start until about 10 years from the onset of the disaster.

The government and TEPCO plan to conduct a detailed investigation next fiscal year on the technology needed to decommission the Fukushima plant's crippled reactors, then make a final decision on whether it is possible to start the removal work earlier.

In a news conference on June 10, a representative of the Ministry of Economy, Trade and Industry's Agency for Natural Resources and Energy said that bringing forward the plans would be dependent on developing technology, and suggested that the plans might even end up being delayed.

Minister of Economy, Trade and Industry Toshimitsu Motegi played a leading role in revising the roadmap. This has raised suggestions that announcing plans to start removing the fuel earlier than originally forecast is a way for the government administration to underscore its achievements since taking over the reins of government last year, ahead of the upcoming House of Councillors election.

University of Tokyo professor Satoru Tanaka, who is familiar with the decommissioning of nuclear plants, commented, "There is merit in bringing the plans forward to speed up residents return (to areas contaminated by the nuclear accident). But there remains a lot of unchartered technology, and the government needs to support research and development in the future."



Partager cet article
Pour être informé des derniers articles, inscrivez vous :
Commenter cet article