As for the scale of the [Fukushima] accident… we simply don’t know… all the measuring equipment was destroyed at the time of the accident…
The Japanese government has reported estimates [of] 1.5×10^16 Becquerels of Cs-137, which would make it a release of 168 times more radioactive material than the Hiroshima bombing. And this is only material released into the atmosphere… Continue reading »
Associated Press, Mar. 10, 2014: The number of workers who were exposed to more than 5 millisievert – the benchmark annual exposure level for seeking labor compensation for developing leukemia – had fallen to 98 in June 2013 but surged back as high as 398 in October before slightly leveling off to about 250 in January.
Asahi Shimbun, Mar. 9, 2014: About half of the workers at the Fukushima No. 1 nuclear power plant in the three years since the triple meltdown have been exposed to more than 5 millisieverts of radiation, a level used as a radiation exposure reference for humans. The levels of radiation exposure among workers at the crippled Fukushima plant have decreased since the 2011 nuclear accident, but there was a spike from last summer with the problem of dealing with the growing volume of radiation-contaminated water.
Professor Hiroaki Koide, Kyoto University Reactor Research Institute, Apr. 24, 2013: […] the Sendai High Court […] acknowledges a danger of low-level radiation exposure, it says no immediate risk on health. In addition, it concludes the only solution is to evacuate or relocate; changing schools is not enough to avoid radiation exposure over 1mSv/y. Yes, that point of the conclusion is absolutely right. In order to avoid radiation exposure over 1mSv/y, there’s no other way to evacuate from contaminated areas including Koriyama city. The government has responsibility to do so, and I’ve been insisting so. In spite of that, the judgment dismisses a claim of plaintiffs saying they may be able to evacuate or relocate anywhere if they want safer environment below 1mSv/y. The problem is clear that the government is responsible for this forcible radiation exposure toward children; people in contaminated areas are not responsible for. The Court which cannot recognize this point is very much like a slave of nation.
Hiroaki Koide, Kyoto University Reactor Research Institute: You should think robot can’t do anything basically. It has nothing to do with settling the situation. […] They can’t be a help at all. […] Japan hasn’t developed a robot for nuclear emergency at all on the assumption that nuclear accident can never happen. However, some European nations and US have such robots indeed, but their capacity is very limited regardless of remote controlling technology. After all, it must be done by human.
Hiroaki Koide, Kyoto University Reactor Research Institute: There are a lot of problems and Tepco and Japanese government state they are going to pick the melted fuel up someday, somehow. I personally think it’s impossible. Because there is no solution, we will have to give it up. We will have to build stone coffin like Chernobyl for reactor 1, 2 and 3. However, at least they must remove the fuel assemblies on the bottom of spent fuel pools somehow before building stone coffin.
Professor Hiroaki Koide, Kyoto University Reactor Research Institute, during July 29, 2012 lecture at Doshisha University: According to government’s research, Tokyo area turned out to be as contaminated as radiation controlled area like in Fukushima. Millions of people are living in radiation controlled area, where I work with a small nuclear reactor.
In-depth update from ABC-Australia’s Mark Willacy, the ABC’s Japanese-speaking correspondent based in Tokyo.
Willacy interviews Japanese nuclear professor Hiroaki Koide, US energy policy adviser Robert Alvarez, TEPCO spokesman Yoshimi Hitosugi, undercover journalist Tomohiko Suzuki and most importantly retired diplomat to Switzerland, Misuhei Murata.
Murata states he has written to UN Secretary-General Ban Ki Moon, urging international intervention to save the world from another bigger nuclear catastrophe of the spent fuel pool at Unit 4 failing and releasing huge extra amounts of deadly radiation.
Some nuclear experts are warning that spent fuel rods at a damaged plant in Japan could trigger a major catastrophe despite the government’s declaration in December that the emergency phase of the nation’s worst nuclear disaster was over.
Fifteen months after a magnitude-9 earthquake and tsunami struck the Fukushima Daiichi plant and led to meltdowns, fears about reactor 4 have grown as its building holds a storage pool filled with 1,535 nuclear fuel rod assemblies.
New York — Description: Japanese Nuclear Scientist and Japanese and US medical doctors to discuss current radiological health conditions and concerns in Japan after the Fukushima Daiichi nuclear reactor catastrophe.
Hiroaki KOIDE / Nuclear Reactor Specialist and Assistant Professor at Kyoto University Research Reactor Institute
Now, even taking low estimate the amount of cesium-137 that is contained in the [No. 4] spent fuel pool, it’s roughly 5,000 times the amount of cs-137 released during the Hiroshima bombing.
During the press conference in New York after the lecture on the status of Fukushima Nuclear Power Plant accident and radiation contamination in Japan, Dr. Koide of Kyoto University repeated his mantra (or curse, to many Japanese) that the food contaminated with radioactive materials from Fukushima should be consumed by adults who have allowed the nuclear power plants.
It has been discovered by TEPCO’s analysis that the significant amount of Reactor 1’s melted fuel pierced through the steel Reactor Pressure Vessel and dropped onto the Containment Vessel, then melted the concrete at the bottom of the CV. It is estimated that the melted fuel may have eaten into the concrete to maximum 65 centimeters deep.
Maximum 65 centimeters deep from the bottom of the concrete floor, right?
Well no. It’s 65 centimeters from the bottom of the deep groove on the concrete floor.
And neither NHK nor TEPCO would bother to tell you how deep the groove is.
At least, NHK Kabun (NHK’s last remaining conscience, as far as I’m concerned) tweeted and gave the link to its blog post, where NHK’s analysis of the concrete-eating corium is shown with the screenshots from the program: Continue reading »
TOKYO — Molten nuclear fuel may have bored into the floor of at least one of the reactors at the stricken Fukushima Daiichi nuclear power plant, the complex’s operator said Wednesday, citing a new simulation of the accident that crippled the plant in March.
The simulation suggested that the meltdown may have been more severe than had previously been thought.
Soon after an earthquake and a tsunami on March 11 knocked out cooling systems at the power plant, nuclear fuel rods in three of its six reactors overheated and slumped, the operator, the Tokyo Electric Power Company, has said.
In the No. 1 reactor, the overheated fuel may have eroded the primary containment vessel’s thick concrete floor, and it may have gotten almost within a foot of a crucial steel barrier, the utility said the new simulation suggested. Beneath that steel layer is a concrete basement, which is the last barrier before the fuel would have begun to penetrate the earth.
Some nuclear experts have warned that water from a makeshift cooling system now in place at the plant may not be able to properly cool any nuclear fuel that may have seeped into the concrete. The new simulation may call into question the efforts to cool and stabilize the reactor, but the Tokyo Electric Power Company, or Tepco, says it is not worried more than eight months after the accident.
The findings are the latest in a series of increasingly grave scenarios presented by Tepco about the state of the reactors. The company initially insisted that there was no breach at any of the three most-damaged reactors; it later said that there might have been a breach, but that most of the nuclear fuel had remained within the containment vessels.
“This is still an overly optimistic simulation,” said Hiroaki Koide, an assistant professor of physics at the Kyoto University Research Reactor Institute, who has been a vocal critic of Tepco’s lack of disclosure of details of the disaster. Tepco would very much like to say that the outermost containment is not completely compromised and that the meltdown stopped before the outer steel barrier, he said, “but even by their own simulation, it’s very borderline.”
“I have always argued that the containment is broken, and that there is the danger of a wider radiation leak,” Mr. Koide said. “In reality, it’s impossible to look inside the reactor, and most measurement instruments have been knocked out. So nobody really knows how bad it is.”
Conditions inside the Fukushima nuclear plant in Japan remain grim and shambolic eight months after the site was devastated by an earthquake and tsunami, according to the first journalists allowed inside since the disaster.
Officials showed reporters around the plant for the first time since March when the natural disasters triggered a meltdown in three of the plant’s reactors, the worst nuclear accident since Chernobyl 25 years ago.
Martin Fackler, the New York Times’ Tokyo bureau chief, said the site was strewn with piles of rubble virtually untouched since the tsunami struck.
He said: “There’s debris all around where the reactors are – twisted metal, crumpled trucks, large water tanks that have been dented and bent.
“You can see that this stuff has been strewn around and it has not been picked up and it’s been there for eight months.
“So I think that more than anything is a testament to how difficult a time they’ve had in trying to get those reactors under control.”
Radiation levels were still “very high”, he told BBC Radio 4’s Today programme.
The visitors all wore full protective suits, double layers of gloves and plastic boot covers and hair nets, and carried respiration masks and radiation detectors, as the site remains highly radioactive. (Shaking my head in disbelief.)
Tokyo – Scientists, environmentalists and citizens groups have called for Japanese authorities to evacuate more areas in the wake of March’s nuclear accident after finding wider radiation contamination than officially reported.
Researchers have found up to 6.15 million becquerels per square metre of soil in Fukushima city, 60 kilometres north-west of a nuclear power plant that has been leaking radioactive material into the environment since it was damaged in an earthquake and tsunami in the spring.
The measurement is four times higher than the levels used to declare mandatory evacuation areas around Chernobyl, Ukraine, after the 1986 nuclear accident there, the Japanese branch of the environmental organization Friends of the Earth said.
‘The government should encourage children and pregnant women to evacuate’ the affected areas, Kanna Mitsuta, a Friends of the Earth researcher who participated in the survey, said Thursday.
Residents in the town’s district of Watari also found their Geiger counters going off their scales, which go up to 10 microsieverts per hour, Mitsuta said.
Tokyo’s Setagaya district officials said an investigation today of a “high” radiation reading in the area indicates it may not have come from the crippled Fukushima reactors.
The district in the western part of the capital said earlier today it will expand tests in 258 locations after a local resident alerted authorities to a radiation spike that required partially blocking off a sidewalk to the public.
Investigators entered an unoccupied house alongside the sidewalk and radiation readings led them to remove floorboards where they found a case of unidentified substances in bottles, public broadcaster NHK reported.
“When a dosimeter was brought close to the bottles the radiation readings exceeded the limit of the device,” Setagaya Mayor Nobuto Hosaka said in a press conference carried by NHK. No further details were given on the possible contents of the bottles.
The reading was more than 30 microsieverts per hour, NHK reported, which equates to a dose of 157.7 millisieverts per year, or more than 150 times the internationally recommended safety level for the general public, according to a Science Ministry formula.
The discovery follows a flurry of reports this week on a rise in radiation readings in Tokyo and Yokohama, indicating fallout from the Fukushima nuclear disaster has formed “hot spots” in the cities.
As a radiation metrology and nuclear safety expert at Kyoto University’s Research Reactor Institute, Hiroaki Koide has been critical of how the government and Tokyo Electric Power Co. (TEPCO) have handled the nuclear disaster at the Fukushima No. 1 nuclear plant. Below, he shares what he thinks may happen in the coming weeks, months and years.
The nuclear disaster is ongoing. Immediately after the crisis first began to unfold, I thought that we’d see a definitive outcome within a week. However, with radioactive materials yet to be contained, we’ve remained in the unsettling state of not knowing how things are going to turn out.
Without accurate information about what’s happening inside the reactors, there’s a need to consider various scenarios. At present, I believe that there is a possibility that massive amounts of radioactive materials will be released into the environment again.
At the No. 1 reactor, there’s a chance that melted fuel has burned through the bottom of the pressure vessel, the containment vessel and the floor of the reactor building, and has sunk into the ground.From there, radioactive materials may be seeping into the ocean and groundwater.
One figure who has entered the public spotlight in the wake of the nuclear crisis is 61-year-old
Hiroaki Koide, an assistant professor at the Kyoto University Research Reactor Institute and a controversialist in the anti-nuclear debate. A specialist in nuclear power, Koide has garnered attention as a persistent researcher who has sounded the alarm over the dangers of this form of energy without seeking fame.
In a TV Asahi program on June 16, Koide made the following comment:
“As far as I can tell from the announcements made by Tokyo Electric Power Co. (TEPCO), the nuclear fuel that has melted down inside reactors at the Fukushima nuclear plant has gone through the bottom of the containers, which are like pressure cookers, and is lying on the concrete foundations, sinking into the ground below. We have to install a barrier deep in the soil and build a subterranean dam as soon as possible to prevent groundwater contaminated with radioactive materials from leaking into the ocean.”
His comment captured public interest and when I asked a high-ranking government official about it, the official said that construction of an underground dam was indeed being prepared. But when I probed further, I found that the project was in limbo due to opposition from TEPCO.
In the testimony in the Japan’s Upper House Government Oversight Committee, Hiroaki Koide of Kyoto University said there was an outside pressure on him and his colleagues not to release the survey data including the radiation data on March 15.
He talks straight.
The committee hearing is still on-going. Access is still spotty.
Hiroaki Koide of Kyoto University is testifying in the Upper House government oversight committee. The session is broadcast over the Internet, but the Upper House site is being overwhelmed with access requests.
Alongside Koide, Masashi Goto, whistleblower ex-Toshiba engineer who designed the containment vessel at Fukushima I Nuke Plant, Masayoshi Son of Softbank, geologist Katsuhiko Ishibashi are also there.
(Ishibashi insists on doing it (dealing with Fukushima I Nuke Plant) by the Japanese experts only.)
In the meantime, angry and concerned parents and citizens are swarming the Ministry of Education and demand that the government withdraw the 20 millisievert/year radiation (external only) limit for children. The Minister is hiding.
They are holding a meeting outside the Ministry. Each time some punk of a bureaucrat utters something, he is being shouted down by angry protesters, demanding the Ministry retract 20 millisievert/year.
“Why can’t you understand? What can’t you understand?” they are shouting at the bureaucrat.
The China Syndrome refers to a scenario in which a molten nuclear reactor core could could fission its way through its containment vessel, melt through the basement of the power plant and down into the earth. While a molten reactor core wouldn’t burn “all the way through to China” it could enter the soil and water table and cause huge contamination in the crops and drinking water around the power plant. It’s a nightmare scenario,the stuff of movies. And it might just have happened at Fukushima.
Koide is practically agreeing with Christopher Busby that there’s not much anyone can do to stop the release of radioactive materials and further contamination of air, soil and water, other than somehow “entomb” the reactors (a.k.a. Chernobyl solution).
Koide reiterates his view that the corium (he says “melted fuel” and “melted core” in the interview for lay people, but it is melted fuel, and anything else that melted with the fuel inside the RPV) may have already escaped the Containment Vessel in the Reactor 1.
Following is my notes as I jotted down the salient points Koide made in the interview: Continue reading »