Fukushima Update 2020

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Nine years ago, three nuclear reactors melted down in Fukushima. For nine years Japan has put enormous effort into dealing with – and downplaying – the disaster.

Why the downplaying and denial? After nine years the wrecked Fukushima Daiichi nuclear power plant is still dangerous, while further dangers still lurk in the food, water, soil and air. Could it be to protect the Japanese nuclear industry and its embedded bureaucrats?

This past year more evidence has emerged of the highly radioactive microparticles to which Japan’s Olympic guests risk being exposed this summer [1]. These are microparticles of nuclear reactor fuel, 2 – 3 micrometres in size and rich in caesium. It is believed that they were formed when reactor 3 exploded, it’s fuel vapourising at 3,000°C then rapidly cooling and condensing.

These microparticles have been found as far as 320 km away from the nuclear power plant and 200 km away in Tokyo, while 80 km away, topsoil in some areas has been found to contain as many as 100 particles per gram. They are glassy, near-insoluble and so tiny that they float like dust and, if breathed in, they penetrate lung tissue and lodge there, permanently, bombarding the surrounding cells with radiation. This can cause cancer. Astonishingly it seems that they have never been part of the public health reaction.

All Olympics visitors are at risk of receiving higher doses of radiation than need be. They can’t avoid breathing and hot summer air can be dusty. While the South Korean athletes will bring their own food, water and radiation detectors, other visitors may not be aware of the risks and many will be unable to read labelling, ask about where their rice, fish, tea, plums etc., are from, or read radiation survey results. It appears that the Japanese government is going out of its way to hide and deny rather than to help visitors and residents with this information.

Some small steps forward have been made towards  decommissioning the ruined Fukushima Daiichi nuclear plant in the last year. Having removed the spent fuel from reactor 4, they have now removed 5% of the contents of the spent fuel pool in reactor 3 (Feb 2020). However, reactors 1 and 2 still have full spent fuel pools, up on the 4th floor. So let’s hope no earthquake demolishes the buildings during the Olympics, or in the next decade.

They have also removed the top 9 meters of the highly radioactive Unit 1 and 2 vent tower, leaving 111 meters to go.

In the only trial of any Tepco officials concerning the meltdowns, the 3 executives charged were found not guilty of failing to protect the plant from tsunamis, even though they were aware of a government report from before 2011 which predicted tsunamis of 15.3 metres, whereas the plant only had defences up to 13 meters. 15.3 meters was almost exactly the size of 2011’s tsunami.

During the past year Tepco admitted the following:

1. That there had been a leak from the Pressure Containment Vessel cap (PCV) of reactor no. 1 early in the accident. Bolts on the PCV lid had stretched, and the gasket between the metal lid and concrete body had blown. In their words, November 2019: “Check the status of the flange portion of the PCV upper lid, which is estimated to have become a major leakage path at the time of the accident.” Previously denied by Tepco and the global nuclear industry because it means all other Boiling Water Reactors worldwide are also unsafe, with ineffective containment. As Arnie Gundersen of Fairewinds had said in 2012.

2. That there was damage to the reactors before the tsunami, due to the earthquake alone. They spoke of an inspection aimed at ‘damage to containment and torus from the earthquake‘, ie not from the tsunami.

3. That the million tonnes of filtered water still contains radioactive isotopes of iodine, caesium, strontium, etc.  “Much of the radioactive water stored at the plant isn’t clean enough and needs further treatment if it is to be released into the ocean.” There is almost no information available from Tepco about which isotopes remain in how much of the water, just that 80% of the million tonnes is not ‘clean enough‘.

4. That the area inside the ‘icewall’ probably leaks, as radiation levels in the harbour go up when it rains. Rainwater falling directly inside the icewall, or passing under it – or even through it – becomes contaminated as it then flows through the site. This causes a surge of filthy radioactive water to flow on out into the harbour. If it is flowing out from under the icewall, this is an insoluble problem.

In reactor 1, they have postponed the removal of the spent fuel from 2023 to 2027/8. For this they will test the use of robots which run on springs and hydraulics, as electronic ones break. Microchips and motors both get fried by radiation.

In reactor 2, they lowered a robot claw down on to the melted down mass under the reactor, but found the pebble-like material there to be less radioactive than expected at 7.6 Sv/h. This material is a ‘cap’ of lighter metals, from the fuel racks etc. The heavier uranium fuel (300 Sv/h) has settled out, burnt down below it into or through the concrete base. Possibly making retrieval impossible. A sarcophagus would have to be built. At present, it is difficult to clearly say we are going to remove all fuel debris,” said Akira Ono, who leads Tepco’s decommissioning project. Meanwhile, they plan to use a crane on new railway tracks on the roof to remove the spent fuel. Eventually.

In reactor 3 a whiteish blobby material from the corium-concrete interaction was found to be splattered all over the spent fuel pool outside the PCV as well as around the PCV interior. So these white blobs were already forming at the time reactor 3 exploded. Large blobs (1 to 3 inches) were able to escape containment, not just microparticles, raising new questions about the amount of fuel that escaped.

Overall, Tepco is getting to the harder bits, 9 years in, and showing us all how impossible it is to clean up nuclear meltdowns. So let’s stop building nuclear reactors: renewables are indisputably cheaper, quicker, safer and cleaner. 

Written by Kick Nuclear, London, www.kicknuclear.com,

with thanks to www.simplyinfo.org/

[1] www.safecast.org/2019/08/fukushima-cesium-enriched-microparticle-csmp-update/

福島 最新情報 2020年





 今年夏の東京五輪に参加する人々は放射性粒子にさらされそうであるという証拠が、ここ1年間でますます多く出てきています [1]。放射性粒子とは、核燃料が大きさ2~3マイクロメートルの断片になったもので、セシウムをたくさん含みます。3号機が爆発した際に3000℃の高温で気化した後、急速に冷めて凝縮したものと考えられています。
















 2号機内部には、原子炉の下に溶け落ちた核燃料をつかむための機材を入れてみたところ、放射線量が7.6シーベルト/時(Sv/h)と予想より低水準でした。使用済み核燃料を保管するための棚などの金属が溶け、蓋のように被さっていたようです。より質量の大きいウラン(300 Sv/h)は溶け出して、下の方へ潜ったか、コンクリートの底を突き抜けたはずです。そうであれば、溶融燃料の取り出しなど不可能でしょう。原子炉全体を石棺で覆うしかありません。東電の福島第一廃炉作業を率いる小野明氏は、現時点で全ての燃料デブリを取り出せる時期を明確に示すことはできないと述べています。こうした中、建屋の天井にクレーンを取り付けて使用済み核燃料を取り出す計画も進めています。



文責:キック・ニュークリアー・ロンドン http://www.kicknuclear.com

http://www.simplyinfo.org/ への謝意とともに

[1] http://www.safecast.org/2019/08/fukushima-cesium-enriched-microparticle-csmp-update/