Fuel meltdown experiment eyed to learn more about Fukushima crisis

Kyodo

The Japan Atomic Energy Agency is planning to melt a small nuclear fuel rod in an experiment at its research facility in March to figure out how meltdowns occurred at the Fukushima No. 1 nuclear power plant in 2011, officials said Thursday.

The experiment could offer clues about the uncertain state of the melted fuel inside the three crippled Fukushima No. 1 reactors. Removing the fuel from the reactors will be the biggest challenge in dismantling the plant.

“We hope to use the data obtained through the experiment to improve the accuracy of the analysis of the Fukushima accident,” a JAEA official said.

During the experiment, to be conducted at the Nuclear Safety Research Reactor in Tokai, Ibaraki Prefecture, nuclear fission reactions will be triggered using a 30-cm-long test fuel rod placed inside a stainless-steel capsule.

The agency will study at what temperature fuel starts to melt as well as the rate of melting.

To create conditions similar to the Fukushima crisis, in which reactors lost coolant water due to heat generated by the nuclear fuel, the test fuel will not have contact with water. JAEA is also considering installing a camera inside the capsule to record the process.

Due to the loss of reactor cooling functions during the Fukushima crisis, the fuel inside reactors 1 to 3 is believed to have melted through the reactor pressure vessels and been accumulating in the outer primary containers.

The three reactors contained a combined 1,500-some assemblies of fuel rods that were each around 4 meters long.