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Thursday, 9 January 2014

Japanese scientists intend to repeat Fukushima disaster

Japanese scientists are planning to carry out an experiment that would imitate dissolution of nuclear fuel, similar to what took place during the accident at the Fukushima nuclear power plant.


The organization that will be responsible for this experiment is the governmental Organization for Exploring and Developing Nuclear Power.

The experiment’s initiators hope that it will help to learn more about what happens to a nuclear fuel rod after it stops to be chilled. The results of this experiment may probably help to get better prepared for similar catastrophes in the future.
A 1.2-meter high steel capsule will be made for this experiment, and a 30-cm fuel rod will be placed into it. With the help of a special reactor, the scientists will create conditions similar to those that were at the Fukushima power plant during the accident. The process of the rod’s destruction will be filmed and fixed by several special devices. Then, the melted fuel will be sent for further investigations.

The experiment will be held in the Tokai scientific center in the Ibaraki Prefecture. The exact date of the experiment is yet unknown, but most likely, it will take place not earlier than in April 2014.
In March 2011, the Fukushima power plant was hit by a powerful tsunami, which caused a malfunction of the plant’s system of electricity and cooling water supplies. In three reactors, nuclear fuel melted, which was accompanied with explosions of hydrogen and emissions of radiation.
Scientists still know little about the essence of such processes. In particular, there is no data about how much time the melting of the fuel and the destruction of the rods at the Fukushima plant was taking place. So far, scientists have only held computer imitations of such processes, which can give only rather approximate data.

The operator company of the ill-fated Fukushima nuclear power plant in Japan has again proved its incompetence in liquidating the consequences of the catastrophe that hit the plant in the spring of 2011. Initially, TEPCO has announced that it would decontaminate radioactive water from the plant by the end of 2014. Now, the company is saying that it needs another year to complete this task.

However, the plant’s decontaminating system, with the help of which it might have been done, has already been completely shut down – which, as TEPCO itself is now acknowledging, was a mistake. Launching this system again may take a long time, which gives some grounds to doubt whether the radioactive water will really be decontaminated before the new deadline.
Moreover, this is not TEPCO’s first mistake of this kind. Last December, the company also experienced a malfunction within their decontamination equipment that led to the inability to filter radionuclides like strontium and cobalt from the contaminated plant water.

TEPCO, the operator of the Japanese tsunami-crippled Fukushima NPP, plans to start cleaning the underground tunnels believed to be part of the sources of radioactive materials poisoning the underground water in the area.
According to the NHK TV network, the Tokyo Electric Power Company (TEPCO) will first block the flow of tainted water between the damaged buildings and the tunnels. In January workers will begin to bury pipes in the ground and in April they will start to drain the contaminated water from the tunnels.
Since the Fukushima NPP disaster in March 2011, leakage of radioactive water has been the main threat to Japan’s population and environment, as well as to the international community.

On 4 December, the International Atomic Energy Agency (IAEA) advised the Fukushima plant to start dumping toxic water into the ocean after lowering the level of radioactive materials to below the legal limit. Meanwhile, according to a draft report released by Japanese government officials, the Fukushima NPP could run out of storage space for contaminated water within two years. The report suggests covering the ground with asphalt to reduce the rain inflow and building giant tanks with more capacity, as well as installing special undersea filters to reduce the radioactivity of water that leaks into the sea.

To solve the problem, TEPCO has been testing an advanced water processing machine called ALPS which can remove almost all radioactive materials, except for tritium, from tainted water. TEPCO plans to clean all the tainted water with ALPS by the end of March 2015.It says that over 300,000 tons of radioactive water has been stored in 1,000 tanks at the Fukushima plant, and that this amount will double within a few years.

TEPCO acknowledged the fact that contaminated water has been escaping from the basements of the Fukushima plant into the ocean in July 2013. Since then TEPCO reported two major leaks of tainted water from storage tanks into the ocean – 300 tons in August and 430 litres in October.

TEPCO has been widely criticized due to major setbacks in handling the consequences of the nuclear disaster. The public calls to put Fukushima-related work under government control. A former TEPCO employee said last week that one of the reasons for so many leaks could be the cost-cutting measures applied by the company, such as using duct tapes and wire nets to mend the leaking tanks.


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