TEPCO retrieves tiny melted fuel from disaster-hit Fukushima reactor
TOKYO, Nov. 7 Kyodo - The operator of the Fukushima Daiichi nuclear power complex said Thursday it had retrieved a small amount of melted fuel from one of the disaster-stricken reactors, in its first such attempt after the plant was hit by a massive earthquake and tsunami over a decade ago.
The successful extraction of the debris from the No. 2 reactor -- albeit a pebble-like substance less than 3 grams -- is seen as a key step toward the goal of completing the decades-old process of decommissioning the plant, which suffered fuel meltdowns in three reactors in the nuclear crisis that began in March 2011.
An estimated 880 tons of fuel debris, a mixture of melted fuel rods and other substances that later cooled and solidified, remain in the Nos. 1, 2, and 3 reactors.
"We believe we are approaching the stage of conducting full-scale decommissioning work," Japan's top government spokesman Yoshimasa Hayashi told a press conference.
At around 11:40 a.m. Thursday, workers collected an aluminum container carrying the debris, which a remotely controlled device had earlier grabbed from the bottom of the No. 2 reactor's primary containment vessel, according to Tokyo Electric Power Company Holdings Inc.
Radiation levels around the debris have been confirmed to be below 24 millisieverts per hour, a threshold TEPCO has set for the safety of workers involved.
The debris sample was then transferred to a sealed piece of equipment called a "glovebox" at the building housing the No. 2 reactor to measure its size and weight. It will subsequently be sent for analysis at a research facility in neighboring Ibaraki Prefecture.
The whole process has been conducted as a trial, and the analysis is expected to be utilized to come up with the best methods to conduct the retrieval work as well as store the fuel debris.
TEPCO had initially planned to begin the retrieval process in 2021 under the goal of completing decommissioning of the reactors by 2051, but it was postponed three times due to changes in the extraction methods, among other things.
The trial has experienced some setbacks, including at the very beginning on Aug. 22 when there were problems in the preparation work before sending in the retrieval device, designed to be extendable up to 22 meters.
TEPCO resumed the process on Sept. 10 only for the operation to be halted on Sept. 17 after cameras attached to the device stopped working.
The debris was finally grabbed on Oct. 30 and placed just outside the reactor container for retrieval by workers.
==Kyodo
