Why Technical English

Once more about Fukushima accident

April 15, 2013
4 Comments

Composed by Galina Vitkova

Some facts about the NPP

Two years ago, on 11 March 2011, in Japan the strongest earthquake accompanying by tsunami occurred. The earthquake and tsunami waves (the maximum wave height made 40.5 metre) caused widespread devastation across a large part of Japan. More than 14,000 lives lost. In addition to this, at least 10,000 people remain missing. Many more inhabitants were displaced from their homes because towns and villages were destroyed or swept away.

The tsunami caused the serious accident at the Nuclear Power Plant Fukushima-1(or NPP Fukushima Daiichi).

The NPP Fukushima-1 is located near Okum city in Fukushima prefecture. The NPP was built in 1960–1970 and is operated by the Tokyo Electric Power Company (TEPCO). The NPP is equipped with six nuclear units of total capacity 4.7 GW.

Earthquake and accident

The accident at the NPP Fukushima-1 occurred practically immediately after the earthquake and tsunami. The reactors in operation were shutdown. After that the external electricity feed disappeared too. The wave submerged reserve diesel generators, as a result of it the reactor cooling systems of Units 1, 2, 3 failed to function. Active zones of these reactors were melted.

In the wake of the reaction between zirconium and water vapour the hydrogen formed. It leads to a series of explosions and demolition of buildings, where the reactors are installed.

Units 5 and 6 were not destroyed as their diesel generator kept intacted. With the help of it two reactors and two spent nuclear fuel pools were managed to be cooled.

The accident impact and radioactive pollution

As a consequence of the NPP accident radioactive substances, among them iodine 131 (with very short half-life period) and ceasium 137 (with 30 years long half-life period), were emitted into the atmosphere and the see. On the site a few of plutonium was also found out. The radioactive contamination of the marine environment occurred by aerial deposition and by continuing discharges and outflow of water with a various level of radioactivity from the four damaged reactors at the NPP.

Total quantity of radioactive releases made 20 % of emissions after the Chernobyl disaster. In order to reduce the external exposure to the population beyond a distance of 30 km from the Fukushima-1 inhabitants were evacuated from this area . The contaminated land area, which should be deactivated, makes 3 % of the Japan territory.

Radioactive substances were revealed in drinking water and food not only in Fukushima prefecture, but in the other regions of Japan, too. Many countries including Russia banned to export of Japanese products. Following the accident at the Fukushima NPP on 11 march 2011, the European Union approved the Implementing Regulation of 26 October 2012. The Regulation imposed special conditions governing the import of feed and food originating in or consigned from Japan .The controls performed at import show that these special conditions are correctly implemented by the Japanese authorities. A next review of the Regulations is foreseen to be available by 31 March 2014.

For the first time after the Chernobyl accident in April 1986 the reputation of nuclear power was damaged so seriously. The world put on considering cap if nuclear power could be safe. Many countries blocked projects in this industry. Germany declared that by 2022 it will shut down the last NPP and will develop renewable sources of electricity production.

Removal of the accident impact

In compliance with the government of Japan intentions the full removal of the consequences of the accident at the NPP Fukushima-1 will take 30 to 40 years. In December 2011 cool shutdown of reactors was completed. After that the work on extracting of spent nuclear fuel from the spent nuclear fuel pools commenced. Then the nuclear fuel from entire reactors is supposed to be extracted. After that the complete demolition and decommission of the NPP technological equipment should be performed.

New accident

On 18 March 2013 in the evening a new accident caused by failure of cooling systems of spent nuclear fuel pools of Units 1, 3, 4 occurred. It happened after power outage at the NPP Fukushima-1. On 19 March the company ТЕРСО managed to put into run the cooling system of Unit 1. Nevertheless, troubles and problems in the cooling systems of Units 3, 4 and in the common pool continue till now.

Notes

  • Nuclear power produces about 14 % electricity production in the world.

  • In Japan the production of electricity in the year 2007 before Fukushima accident made 264 TWh with the installed capacity of 49 GW (i.e. 23,5 % of total Japanese NPP installed capacity).

  • In Germany electricity produced with NPP installed capacity of 20 GW (23,5 % of total German installed capacity) in the year 2007 amounted to 141 TWh. You can see changes in Germany energy policy after the Fukushima accident in Energy policy of Germany after Fukushima,and in Германия после Фукусимы.

  • You can find more details about about world producers of electricity in
    Statistics on nuclear power.

If you are tired by studying figures, take a rest and fix your eyes on the picture below. Enjoj!

hnízdo2

Abbreviations

NPP – Nuclear Power Plant
ТЕРСО – Tokyo Electric Power Company
TWh – terawatt hour
GW – gigawatt

References

http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2012:299:0031:0041:EN:PDF , Official Journal of the European Union
http://www.iaea.org/newscenter/news/tsunamiupdate01.html
http://www.aif.ru/society/,March 2013, Аргументы и Факты, март 2013
http://www.world-nuclear.org/info/Safety-and-Security/Safety-of-Plants/

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