nuclear-news

Recovery, remediation, decommissioning at Fukushima

Managing contaminated water involves removal of the sources of contamination and isolating ground water from sources
Full remediation and decommissioning of reactors at Fukushima may take a long time. Hasty schedules are not possible or expected as they clash with the safety of people. Water flowing over the melted cores of Units 1, 2 & 3 stricken by the earthquake and tsunami carries a cocktail of radio-nuclides. The integrity of the primary containment vessels of these reactors is not known. They have to develop the needed technologies to handle the cores; it may face its own trials and tribulations.
Fukushima now witnesses a beehive of activity. In April 2013, exactly two years after the accident, the site engaged 2950 workers in various remediation tasks. By February 2014, the work force grew steadily to 7150.
Mr. Naohiro MASUDA, chief decommissioning officer and president of Fukushima Daiichi Decontamination and Decommissioning Engineering Company presented updates of the progress thus far, and the future plans at an international conference organized by the Japanese Atomic Industrial Forum on April 13-14, 2015 at Tokyo.
He covered, among other topics: the present status of the plants; measures against contaminated water; fuel removal from the spent fuel pool and fuel debris removal.
The Tokyo Electric Power Company (TEPCO) maintains the reactors at cold shutdown stage by continuously injecting water into them. The operators removed spent fuel rods from the spent fuel pool at Unit 4 by Dec 22, 2014. Now they plan to remove fuel debris from Units 1, 2 and 3.
Maximum dose rate at the site boundary is only 0.03 mSv per year, as against allowed limit of one mSv per year.
Managing contaminated water is a humongous challenge. It involves removal of the sources of contamination, isolating ground water from sources and prevention of water leakage.
TEPCO uses 16 specially designed pieces of equipment each of which can remove one or more of the sixty-two different radio-nuclides including caesium-137 and strontium-90 from water. Each may process 250 to 1200 cubic metres per day. Tritium is a major issue. TEPCO is reportedly discussing with fishermen for its gradual release into sea.
Daily, about 400 tonnes of ground water enter the building. As this water gets contaminated, it has to be stored and decontaminated. Besides other methods, TEPCO plans to construct a frozen soil impermeable wall on the land side to prevent entry of ground water. The wall will use refrigerated coolant at minus 30 degree Celsius, running through pipes that have been placed vertically in the ground, to freeze the surrounding soil.
“There are many underground pipes and other structures associated with each of the four generating units. Building a watertight physical structure around all those obstacles would be nearly impossible and, even if it could be done, the construction would be more complex, time consuming, and disruptive.
It likely would also generate much more potentially contaminated excavated soil that would need to be safely disposed of,” TEPCO stated at its website…
The wall will be in place for six years, the period needed to drain and clean the contaminated water from the buildings and make them watertight.
According to Hiroshi Kainuma, Fukushima University, the yield of rice in Fukushima came down from 4, 45, 700T in 2010 to 3, 53,600 T in 2011. In 2013, it rose to 3, 82,600T closer to earlier years.
In 2012, 71 bags of food had radioactivity above the legal reference value. In 2013, 28; in 2014, no such bag was found.
Neither abortions nor abortion rates have increased in Fukushima. Divorce rate has not increased.
Birth rates lowered. Kainuma noted that the number of direct deaths caused by earthquake and tsunami in Fukushima was 1612; the number of disaster-related deaths due to evacuation was higher at 1793!
Decontamination specialists, with unenviable tasks assigned to them used, on large industrial scales, technologies which were successfully deployed on small scales. There were failures. Diligent auditors did not condone such ‘aberrations.’ You may express empathy or sympathy or hostility on that action depending on which side of the isle you are in!
The reactor owners, regulators and others responsible to operate the Fukushima Daiichi plants safely managed to melt the cores of three of them, throwing nuclear industry world-wide into disarray! Ultimately, the Japanese ingenuity and their expertise in robotics, miniature electronics, and precision engineering will win the day. Japan needs nuclear power; many plants will start operation, though presently only energy specialists look at them benignly.
Source : The Hindu
http://www.thehindu.com/sci-tech/science/recovery-remediation-decommissioning-at-fukushima/article7278520.ece

June 6, 2015 Posted by dunrenard | Japan | Fukushima Daiichi | Leave a comment

Issues of Incineration Disposal of Agricultural and Forestry Radioactive Wastes in Fukushima Prefecture by Toshikazu Fujiwara

Makeshift incineration facilities in Minamisoma City, Fukushima Prefecture

June 2, 2015

The Fukushima Daiichi Nuclear Power Station accident released radioactive substances across a wide area of the environment. Currently, not only decontamination operations but also people’s everyday lives generate wastes that include high concentrations of radioactive substances. The Japanese government terms radioactive wastes from 8,000 to 100,000 becquerel per kilogram (Bq/kg) designated wastes. They are today stored temporarily at various locations, while at some point in the future, after reducing their volumes, the government plans to bury them in the prefectures where they were generated. In this article, Toshikazu Fujiwara, who is well-versed in the volume reduction of these contaminated designated wastes, discusses the issue. (Nobuko Tanimura)

Introduction

In Fukushima Prefecture, the Japanese Ministry of the Environment is promoting the Waste Volume Reduction Project, which, by means of makeshift incineration facilities, incinerates the combustible wastes that are specifically designated according to the level of contamination (at or over 8,000 Bq/kg) attributed to the radioactive substances emitted from the Tokyo Electric Power Company’s Fukushima Daiichi Nuclear Power Plant. The combustible designated wastes include agricultural and forestry byproducts such as paddy straw, feed crops, fallen leaves, and manure; sewage sludge; and wastes from home cleaning.

According to the project, the construction of 24 makeshift incinerators is being carried out in 19 municipalities in the prefecture, most of which are already in service.

The first of these incinerators to be constructed is located in Samegawa Village, Fukushima Prefecture. Having been built as a demonstration incinerator, it has the following formal purposes: 1) reducing volumes of wastes; 2) checking safety and associated factors as well as accumulating knowledge concerning the incineration of radioactive contaminated wastes exceeding 8,000 Bq/kg; and 3) determining the environmental impacts of radioactive cesium and other substances after incineration. However, the incinerator constructed in Samegawa was presumably a preliminary project in preparation for subsequent large-scale waste incineration projects.

Problems of the waste volume reduction project

(1) Deceitfulness concerning the project’s purpose

The waste volume reduction project states as its purposes improvement of the living environment for the restoration of the region and for the encouragement of the return of the people who used to live there, and making contributions to the progress of decontamination programs and the recovery of Fukushima Prefecture. Nevertheless, the waste volume reduction project totally ignores the risk of accidents, such as explosions associated with the incineration of radioactive contaminated wastes (the Samegawa makeshift incineration facilities exploded on the ninth day after the commencement of full-scale incineration services), environmental contamination, and health impacts on the people living in the neighborhood.

(2) Defects and procedural contraventions in the Special Measures Act

The legislation on which the wastes are designated and waste volume reduction programs are promoted is the Act on Special Measures Concerning the Handling of Environment Pollution by Radioactive Materials Discharged by the Nuclear Power Station Accident, established on August 30, 2011. This Act has the following fundamental defects: 1) while the procedure for designating wastes is stipulated, the procedure for removing wastes from the designation is not included; 2) the Act specifies that wastes exceeding 8,000 Bq/kg should be treated as designated wastes and wastes exceeding 100,000 Bq/kg should be stored in interim storage, but these radioactivity criteria are not scientifically persuasive; 3) the amounts of the designated wastes are overestimated because they were not determined by proper investigation; 4) the Act does not oblige Tokyo Electric Power Company, the company responsible for the emissions, to perform countermeasures, such as the prevention of radioactive substance discharge and the collection, disposal, and storage of contaminated wastes; and 5) the Act includes no procedural stipulation for information disclosure and accountability to, or the agreement of, local residents, all of which should be preconditions for waste incineration.

(3) Probability of environmental pollution and health risks

I assume that no country has so boldly promoted the incineration of radioactive wastes attributed to a nuclear power plant accident as in the Fukushima case presented in this article. Furthermore, the Ministry of the Environment has been mixing the designated wastes exceeding 8,000 Bq/kg with less contaminated wastes before incineration in order to reduce ash contamination per unit volume and thus prevent the ashes from exceeding 100,000 Bq/kg, over which they would need to be stored in interim storage facilities. The Ministry has repeatedly explained that the incineration of designated wastes exceeding 8,000 Bq/kg by means of the makeshift incineration facilities is safe, because the facilities are provided with bag filters that capture 99.99% of radioactive substances (mainly radioactive cesium particles) in the exhaust gas emitted through the incinerator funnels, reducing them to an undetectable level. However, gaseous substances and microparticles such as particulate matter 1.0 are known to be emitted through the filters, and bag-filter applications in conventional incinerators confirm that the filters break down easily. According to the makeshift incineration facilities test project commissioned by the Ministry of the Environment and performed by the Japan Atomic Energy Agency (JAEA) in Okuma Town and Iitate Village, Fukushima Prefecture, the mass balance analysis that compared the amounts of cesium in the wastes loaded into the incinerators and those in the output indicated that the whereabouts of 30% to 40% of radioactive cesium were unknown. The missing amounts of cesium may reside in the incinerator, ducts or funnels, or may be leaking from seals and other leak-susceptible locations in the facilities. If this is the case, incineration is highly likely to cause the spread of radioactive substances in a radius of several kilometers around the facilities, resulting in ground fallout and thus contamination of the land, increasing the health risks to locals. The Ministry of the Environment has performed no risk assessment in this regard.

(4) Financial unhealthiness

The budget the Japanese government has appropriated for this series of waste volume reduction projects is abnormally large. Overseas observers have previously regarded the huge spending by Japanese municipalities on the construction and maintenance of waste incineration facilities as extraordinary. The total cost of just the construction projects for makeshift incineration facilities that we know about, and which are planned to be used for as little as three months to three years, amounts to 400 billion yen. This amount does not include most of the cost of incinerator dismantling or site decontamination. The entire waste volume reduction project is an abuse of an enormous amount of tax revenue. If methods other than incineration were used, a considerable amount of expenses could undoubtedly be saved.

Let’s stop incineration and burial by proposing alternative methods, and establish a Fundamental Law on Radioactive Contamination Prevention!

In consideration of environmental loads and accident risks, the incineration and ash burial of radioactive wastes cannot be the optimal disposal system, no matter if the wastes are those generated anew by the Fukushima nuclear plant accident or the high-level radioactive wastes resulting from conventional nuclear power facilities such as reactors. We must come up with and propose alternative systems to put an end to incineration as quickly as possible.

Source: Citizens’ Nucleat Infomation Center

http://www.cnic.jp/english/?p=3089

June 4, 2015 Posted by dunrenard | Japan | Fukushima Daiichi | Leave a comment

NRA not informed of tainted water transfer

NRA not informed of tainted water transfer: Tepco caught mixing in highly contaminated basment water, claiming it is “rainwater.”
Tepco is transferring wastewater that is more radioactive than it originally stated. The company failed to notify Japan’s nuclear regulator of the change :

In May, officials found that water sampled at 4 sites at the plant’s port exceeded levels of radioactivity seen previously in the 2 years since monitoring began.
It’s believed the contaminated water came from a cracked and leaking hose inside the plant. The water from the hose flowed into a channel that led to the port.
Initially, Tepco said the hose contained wastewater that was a “byproduct of treating contaminated rainwater.”
But on Wednesday it was revealed at a meeting of the NRA that the utility had begun adding other highly radioactive wastewater to the water since mid-May.
Tepco says that as a result the wastewater in the hose was “likely more radioactive than it initially declared.”
Some of the water in the hose was groundwater mixed with extremely highly contaminated water that had pooled in the plant’s basement.
The hose cracked from being bent beyond the operational limit set by the maker. The utility had also failed to replace the hose despite questions about its durability.
NRA Chairman Shunichi Tanaka condemned the utility for its “utter failure to control the wastewater.” He ordered the company to continue monitoring and reporting on its handling of wastewater.
Source : NHK
http://www3.nhk.or.jp/nhkworld/english/news/20150603_37.html

June 4, 2015 Posted by dunrenard | Japan | Fukushima Daiichi | Leave a comment

Wow! Fukushima Leak Could Cause an Explosion?

Paul Gunter seemed to be talking about the Hi-test radioactive sludge sitting at the bottom of the tanks. I thought this was about what soaked into the ground below the tank farm :

Paul Gunter, Beyond Nuclear, joins Thom Hartmann. Another day, another ominous development in Fukushima. According to new numbers from the Tokyo Electric Power Company – or Tepco – the plant’s Operator – as many as 10 percent of the nuclear facility’s containers may be leaking radioactive waste. And while the release of toxic chemicals into the environment is bad enough – this new problems comes with an added risk: it could cause a violent explosion. As one nuclear official told the Telegraph – since the leak was thought to be caused by a hydrogen build-up “If the concentration level is high, a spark caused by static electricity could cause a container to explode.” 

Source:  

https://youtu.be/KPkDRNOCdgY

June 4, 2015 Posted by dunrenard | Japan | Fukushima Daiichi | Leave a comment