8 Sep (NucNet): Japan has chosen three companies to perform demonstrations in a project to verify technologies for separating tritium from contaminated water at the Tokyo Electric Power Company’s Fukushima-Daiichi nuclear power station.
The Mitsubishi Research Institute, which is overseeing contaminated water management for Japan’s Agency for Natural Resources and Energy (ANRE), said the three companies are RosRAO, a subsidiary of Russia’s state nuclear corporation Rosatom, GE Hitachi Nuclear Energy Canada and US-based Kurion.
The project tender document published by the Japan Ministry of Foreign Affairs says the government will pay up to one billion Japanese yen (9.5 million US dollars, 7.3 million euros) per project to build a facility that demonstrates the removal of tritium from radioactive water.
The document says the project is designed to verify the separation performance of tritium separation technology, to assess construction costs and operating costs for installing the system at Fukushima-Daiichi, and for treating water remaining after treatment with existing multi-nuclide removal equipment.
Efforts to remove 62 kinds of nuclides are ongoing, the document says, but it is not possible to remove tritium with existing physicochemical methods. Removing tritium requires an efficient hydrogen isotope separation method such as distillation, electrolysis or a combination of these processes.
The verification tests will be carried out offsite and the companies will be responsible for transporting the treated water to their test sites and then back to Fukushima-Daiichi.
The technology must be shown to be capable of achieving a separation factor higher than 100 and of being able to process up to 400 cubic metres of water a day with a tritium concentration between 0.6 and 4.2 million becquerel per litre (Bq/ℓ). The deadline for the demonstration is 31 March 2016.
The Japan Atomic Industrial Forum (Jaif) said ANRE will assess the performance of the demonstrations. The agency will also look at criteria such as construction and operating costs.
ANRE said the project does not mean the tested systems will eventually be employed at Fukushima-Daiichi.
Contaminated water at Fukushima-Daiichi is being treated with EnergySolutions’ Advanced Liquid Processing System (Alps), which removes 61 radionuclides, but not tritium.
Tritium is a radioactive isotope of the element hydrogen and has a radioactive half-life of 12.3 years. According to the US Environmental Protection Agency, exposure to tritium increases the risk of developing cancer.
However, because tritium emits very low energy radiation and leaves the body relatively quickly, for a given amount of activity ingested, tritium is one of the least dangerous radionuclides. According to radiation protection guidelines, a concentration of up to 7,000 Bq/ℓ would be considered acceptable for drinking water.
