1 Avril 2015
March 31, 2015
A former chief U.S. nuclear regulator asserted Tuesday that the massive volumes of tritium-tainted water stored at the Fukushima No. 1 nuclear plant can be “safely” dumped into the sea after it is diluted to reduce the levels of radioactive tritium below the legal limit.
“Most people don’t know what tritium is, so what they will think about is that it’s bad, something that’s really dangerous. But tritium is an element that we know a lot about,” Dale Klein, chairman of Tokyo Electric Power Co.’s Nuclear Reform Monitoring Committee, told a news conference in Tokyo.
“It can be released safely into the ocean. We know worldwide what the safe limit for tritium release is,” said Klein, who once headed the U.S. Nuclear Regulatory Commission.
Tepco has been treating water stored at the plant with a system known as ALPS (Advanced Liquid Processing System), which removes all radioactive materials except for tritium.
The processing has left the utility with vast amounts of water contaminated with heavy doses of tritium. About 350,000 tons of the water is currently stored in hundreds of large tanks, each of which poses a potential leak risk.
Tepco has said the level of tritium in the water is between 1 million and 5 million becquerels per liter. The legal limit for release to the sea is 60,000 becquerels.
Tritium has a half life of 12.3 years, so it would take decades to die down to permitted levels if left undiluted. The element is about one-thousandth as radioactive as the isotopes cesium-134 and cesium-137, according to Tepco.
Tepco said it has not decided yet what to do with the tritium-tainted water, as a government panel is currently trying to figure out what options are available.
Klein said he understands the option to release the water into the Pacific “is intensely emotional” among local fishermen, but he is confident that the they will eventually agree with his view.
He noted that fishermen in the past agreed to an equally controversial decision to discharge clean groundwater pumped up at the site before it seeps into the reactor buildings and becomes contaminated.
Meanwhile, Tokyo Electric Power Co. said Monday it will release all available radiation data associated with the Fukushima No. 1 plant after facing criticism for failing to promptly announce leaks of radioactive rainwater into the sea.
Tepco said it had a policy of disclosing radiation information for contaminated water stored at the plant facilities if there is a risk of that water reaching the sea. This policy did not cover rainwater in drainage ditches, however radioactive it might be.
The utility has been criticized for not promptly releasing information about radioactive rainwater when it had data confirming leaks had taken place.
Information from Jiji added