14 Novembre 2018
November 14, 2018
IAEA urges quick plan on Fukushima radioactive water cleanup
TOKYO (AP) -- Experts from the International Atomic Energy Agency urged the operator of Japan's tsunami-wrecked Fukushima nuclear plant on Tuesday to urgently decide on a plan to dispose of massive amounts of treated but still radioactive water stored in tanks on the compound.
A 13-member IAEA team told reporters in Tokyo after a weeklong review that managing nearly 1 million tons of radioactive water is critical to the plant's safe and sustainable decommissioning.
The IAEA team said in a preliminary report that hundreds of tanks currently used to store the water over large areas of the plant's compound can only be a temporary solution and must be removed "urgently."
The cores of three reactors at the plant suffered meltdowns following a massive 2011 earthquake and tsunami that devastated parts of northeastern Japan.
Radioactive water has leaked from the damaged reactors and mixed with groundwater and rainwater at the plant. The water is treated and stored in large tanks.
More than 7 1/2 years since the accident, officials have yet to agree on what to do with the radioactive water. A government-commissioned panel has picked five alternatives, including the controlled release of the water into the Pacific Ocean, which nuclear experts say is the only realistic option. Fishermen and residents, however, strongly oppose the proposal.
That option faced a major setback this summer when the plant's operator, Tokyo Electric Power Co., acknowledged that the water, which it said had been carefully treated, was not clean enough. It said the water contains cancer-causing cesium and other elements in excess of allowable limits for release into the environment.
The IAEA interim report said TEPCO could run out of space for tanks in a few years, and the water storage adds to safety risks and could hamper the decommissioning of the plant, which is already an unprecedented challenge.
It said the water problem has improved recently because of measures such as an underground frozen wall installed around the reactor buildings to keep the radioactive water from mixing with groundwater. It suggested that TEPCO could further reduce the amount of contaminated water by cutting back on the use of cooling water injected into the reactors because the temperature of the melted fuel has fallen significantly.
IAEA mission leader Christophe Xerri told reporters that it is uncertain whether all of the melted fuel can ever be successfully removed because too little is known about the damage to the cores of the three reactors.
TEPCO and government officials plan to start removing the melted fuel in 2021. Robotic probes inside the reactors have detected traces of damaged fuel but its exact location, contents and other details remain largely unknown.
"If you don't have the information it's very difficult to say it's possible or not" to remove all the fuel, Xerri said.
The team's final report from its review is expected in late January.
THE ASSOCIATED PRESS
IAEA urges Japan to reach decision soon on handling of radioactive water at crippled Fukushima nuke plant
A team of nuclear experts from the International Atomic Energy Agency urged Japan this week to reach a decision quickly on what to do with treated water that contains low toxicity radioactive tritium, which is accumulating at the crippled Fukushima No. 1 nuclear plant.
“We advised the Japanese government that … (a) decision should be taken very rapidly for the disposition path for water which is stored in these tanks,” said Christophe Xerri, leader of the 13-member team, on Tuesday following a nine-day review of progress on scrapping the Fukushima No. 1 plant, which was damaged in the March 2011 earthquake and tsunami.
“There is space limitation, so some solution has to be decided and implemented,” he said, adding that the volume of treated water containing tritium in tanks is expected to reach the planned capacity within the “coming three to four years.”
As of last Thursday around 970,000 tons of tritium-containing water was stored on the premises of the plant, according to Tokyo Electric Power Company Holdings Inc.
The government has studied options for the tritium-containing water, including releasing it into the sea, as it is regarded as not harmful to humans. The tainted water has been stored in tanks after being produced as a byproduct of cooling the plant’s reactors, which suffered core meltdowns following the 2011 disaster.
But local fishermen and residents have expressed concern about discharging the water, fearing the potential impact on food.
“Controlled discharge to the sea is something which is applied in many nuclear facilities, so it’s not something which is new,” Xerri said, while adding, “Our review was not to advise the Japanese government on one solution or another one.”
“It is up to the Japanese government to decide — in engaging with stakeholders, of course — on the option Japan wants to implement,” he said.
Toyoshi Fuketa, who heads the Nuclear Regulation Authority, has described discharging the water into the sea as the “only” solution.
Tepco has been running the Advanced Liquid Processing System, said to be capable of removing almost all radioactive materials from the toxic water except tritium.
It was the fourth such review conducted by a team of experts from the Vienna-based agency, following two in 2013 and one in 2015. The IAEA will issue its final report by the end of January 2019.
Xerri said his team was impressed by the progress that has been made at the plant since the previous review, including the full operation of a frozen soil wall around the reactors that has reduced the volume of groundwater that enters the reactor buildings.
But he acknowledged many challenges in the decommissioning process, which is set to take “30 to 40 years or even more,” including the removal of melted fuel from the reactors — seen as the hardest part.
When asked about the possibility of discarding the fuel — the location and volume of which remaining within the reactors is yet to be grasped due to high levels of radiation — Xerri said, “We don’t have enough information to tell you yes or no.”