In connection to the article I wrote last August 3, 2017 “Radioactive Contamination of Oceans: Sellafield, La Hague, Fukushima” https://dunrenard.wordpress.com/2017/08/03/radioactive-contamination-of-oceans-sellafield-la-hague-fukushima/
This study is about radioactive 129I travelling the equivalent of a third of the way round the globe, a 15,000 km journey, legally released since 20 years from nuclear fuel reprocessing plants in the UK and France. Of course as usual, in complete disregard of recent studies about the dangerosity of low dose,They emphasise that the radioactivity levels found in the North Atlantic are extremely low and not considered dangerous.
This study still is letting us envisage the travel of the Fukushima Daiichi nuclear plant numerous radioactive contaminants which have been dispersed since March 2011, which still are being dispersed and will be additionally dispersed into the Pacific Ocean.
Radioactive 129I has travelled the equivalent of a third of the way round the globe, since being released from nuclear fuel reprocessing plants in the UK and France. The iodine’s 15,000 km journey begins in the nuclear plants at Sellafield and La Hague and continues via the Arctic Ocean and then southward via the Grand Banks towards Bermuda, where it is found at very low concentrations about 20 years later. This tracer has been used to provide the most complete up-to-date, high-accuracy mapping of the oceanic currents that transport CO2 and other greenhouse gases from the atmosphere to the abyssal depths of the deep North Atlantic Ocean. These results are being presented at the Goldschmidt geochemistry conference in Paris.
Radioactive contaminants have been legally released for more than half a century from the nuclear reprocessing plants at Sellafield (UK) and La Hague (France). Scientists have recently begun to use the radioactive 129iodine (129I) as a way of tracking the movement of ocean currents. They emphasise that the radioactivity levels found in the North Atlantic are extremely low and not considered dangerous.
“What we have found is that by tracing radioactive iodine released into the seas off the UK and France we have been able to confirm how the deep ocean currents flow in the North Atlantic. This is the first study to show precise and continuous tracking of Atlantic water flowing northward into the Arctic Ocean off Norway, circulating around the arctic basins and returning to the Nordic seas in what we call the “Arctic loop”, and then flowing southward down the continental slope of North America to Bermuda at depths below 3000 m” said lead researcher Dr John N. Smith (Bedford Institute of Oceanography, Canada).
The research is part of the international GEOTRACES project, which aims to use geochemical markers to follow ocean currents, and so provide precise estimates of transit times and mixing rates in the North Atlantic and Arctic Oceans. So far the 129I has been measured as far south as Puerto Rico, but the researchers assume that it will continue to flow southward into the South Atlantic and eventually spread throughout the global ocean.
Dr Smith continued, “These currents have previously been studied using dissolved CFCs (Chlorofluorocarbons) – the molecules which used to be used in fridges until banned in 1989. However, CFCs undergo ocean-atmosphere exchange which means that surface water is continually replenished with CFCs during the arctic leg of the journey, whereas the 129I plume retains the initial imprint of its input history over a long period of years. Further, 129I is relatively easy to detect at extremely low levels using accelerator mass spectrometry methods which gives us a large measurement advantage in terms of the signal to noise ratio. Since we know exactly where the 129I comes from and when it entered the ocean, for the first time we can be absolutely sure that detecting an atom in a particular place is as a specific result of the currents”.
“In many ways this is a bit like the old ‘stick in a stream’ game we used to play as kids – what people call ‘Pooh sticks’ in England – where you would drop a buoyant object in the water and observe where it comes out. Of course, it would be much better if these markers were not in the ocean at all, but they are, and we can use them to do some important environmental science”.
Commenting, Dr Núria Casacuberta Arola (ETH, Zurich) said:
“The work performed by John Smith and colleagues in recent years has greatly contributed to the understanding of water circulation, especially in the North Atlantic and Arctic Ocean. The advantage of using 129I as a transient tracer in oceanography is the long half-life (15.7 My) of this isotope compared to the circulation times, and the fact that it is largely soluble in seawater. Now, major efforts are also devoted to find other artificial radionuclides with similar sources and behaviour than 129I (e.g. 236U, 237Np) so that the more tools we have, the better we will understand the ocean circulation. Recent advances in mass spectrometry (ICP-MS and AMS) allow today for very low detection limits so that we can measure very low concentrations of these isotopes in deep ocean waters”.
From December 2011, reposting it today so that people won’t think that the March 2011 Fukushima Daiichi nuclear disaster is behind us.
“After 280 days of decaying, the 257 tons of lost corium from three of Fukushima’s reactors, which one assumes to have a burn rate of 14GWJ/t (14 kg fissioned per tonne), have produced a probable level of radioactivity of 180.37 million Curies, or 6.674E18 Becquerels (6673.6 PBq). […]
92.17% of this radioactivity is being emitted by fission products, and constitutes 28.07% of overall radiotoxicity. 7.83% of this radioactivity is made by activation products, and constitutes 71.93% of overall radiotoxicity. That is to say that here the radiotoxicity, which according to the eminently official ICRP’s dose factors equals 73.47 Billion potential lethal doses via inhalation and 15.53 Billion lethal doses via ingestion, results chiefly from the activation products, which by and large are alpha emitters.
On the other hand, the radioactivity in this case is produced primarily by fission products, which most often are beta (β− ) emitters. At the end of these 280 days of decaying, the radiation arises primarily from the following elements: Strontium 89 at 2.265%, Strontium 90 at 4.713%, Yttrium 90 at 4.713%, Yttrium 91 at 4.852%, …
…Yttrium 91 at 4.852%, Zirconium 95 at 8.067%, Ruthenium 106 at 9.297%, Caesium 134 at 4.737%, Cesium 137 at 6.209%, Barium 137 at 6.209%, Cerium 144 at 23.744%, Promethium 147 at 13.728%, Plutonium 241 at 5.505%, Cobalt 60 at 1.410%.
Consistent with the rate of decay of these 280 days, in 15 years the fuel will have lost 80.20% of its radioactivity, bringing it to 35.71 Curies – but its long-lived toxicity will be elevated by 13.35%, contrarily, to 83.28 Billion lethal doses. Without question, the overall radioactivity falls but the persistent radiotoxicity increases until 60 years or so later, it commences to decline ever-so slowly after 350 years! (This irrefutable augmentation of toxicity over time is largely due to the increase of Americium-241 – alpha – a daughter product far more toxic than its beta-emitting parent, Plutonium-241. Ultimately, it will take around 350 years for the radiotoxicity to return to its original level…”
Via Bruce Brinkman on August 16, 2017
Don’t forget to pick up some delicious Fukushima peaches at the *konbeni* checkout
Never mind the “harmful rumors”
(a.k.a. measurements of cesium 137, cesium 134, strontium 90, americium, plutonium, uranium, and a splattering of other radionuclides)
and as the next days those peaches just aren’t moving: ¥50 off to help sales !
A subterranean ice wall surrounding the nuclear reactors at the stricken Fukushima No. 1 Nuclear Power Plant to block groundwater from flowing in and out of the plant buildings has approached completion.
Initially, the ice wall was lauded as a trump card in controlling radioactively contaminated water at the plant in Fukushima Prefecture, which was crippled by meltdowns in the wake of the March 2011 Great East Japan Earthquake and tsunami. But while 34.5 billion yen from government coffers has already been invested in the wall, doubts remain about its effectiveness. Meanwhile, the issue of water contamination looms over decommissioning work.
In a news conference at the end of July, Naohiro Masuda, president and chief decommissioning officer of Fukushima Daiichi Decontamination & Decommissioning Engineering Co., stated, “We feel that the ice wall is becoming quite effective.” However, he had no articulate answer when pressed for concrete details, stating, “I can’t say how effective.”
The ice wall is created by circulating a coolant with a temperature of minus 30 degrees Celsius through 1,568 pipes that extend to a depth of 30 meters below the surface around the plant’s reactors. The soil around the pipes freezes to form a wall, which is supposed to stop groundwater from flowing into the reactor buildings where it becomes contaminated. A total of 260,000 people have worked on creating the wall.
This photo shows pipes to freeze soil for the ice wall next to the No. 4 reactor at TEPCO’s Fukushima No. 1 Nuclear Power Plant, in Okuma, Fukushima Prefecture, on June 1, 2016. (Mainichi)
The plant’s operator, Tokyo Electric Power Co. (TEPCO) began freezing soil in March last year, and as of Aug. 15, at least 99 percent of the wall had been completed, leaving just a 7-meter section to be frozen.
Soon after the outbreak of the nuclear disaster, about 400 tons of contaminated water was being produced each day. That figure has now dropped to roughly 130 tons. This is largely due to the introduction of a subdrain system in which water is drawn from about 40 wells around the reactor buildings. As for the ice wall, TEPCO has not provided any concrete information on its effectiveness. An official of the Secretariat of the Nuclear Regulation Authority (NRA) commented, “The subdrain performs the primary role, and the ice wall will probably be effective enough to supplement that.” This indicates that officials have largely backtracked from their designation of the ice wall as an effective means of battling contaminated water, and suggests there is unlikely to be a dramatic decrease in the amount of decontaminated groundwater once the ice wall is fully operational.
TEPCO ordered construction of the ice wall in May 2013 as one of several plans proposed by major construction firms that was selected by the government’s Committee on Countermeasures for Contaminated Water Treatment. In autumn of that year Tokyo was bidding to host the 2020 Olympic and Paralympic Games, and the government sought to come to the fore and underscore its measures to deal with contaminated water on the global stage.
Using taxpayers’ money to cover an incident at a private company raised the possibility of a public backlash. But one official connected with the Committee on Countermeasures for Contaminated Water Treatment commented, “It was accepted that public funds could be spent if those funds were for the ice wall, which was a challenging project that had not been undertaken before.” Small-scale ice walls had been created in the past, but the scale of this one — extending 1.5 kilometers and taking years to complete — was unprecedented.
At first, the government and TEPCO explained that an ice wall could be created more quickly than a wall of clay and other barriers, and that if anything went wrong, the wall could be melted, returning the soil to its original state. However, fears emerged that if the level of groundwater around the reactor buildings drops as a result of the ice wall blocking the groundwater, then tainted water inside the reactor buildings could end up at a higher level, causing it to leak outside the building. Officials decided to freeze the soil in stages to measure the effects and effectiveness of the ice wall. As a result, full-scale operation of the wall — originally slated for fiscal 2015 — has been significantly delayed.
A worker makes checks with a hammer on an impermeable wall near TEPCO’s No. 4 reactor in the town of Okuma in Fukushima Prefecture on Feb. 24, 2017. (Mainichi)
Furthermore, during screening by the NRA, which had approved the project, experts raised doubts about how effective the ice wall would be in blocking groundwater. The ironic reason for approving its full-scale operation, in the words of NRA acting head Toyoshi Fuketa, was that, “It has not been effective in blocking water, so we can go ahead with freezing with peace of mind” — without worrying that the level of groundwater surrounding the reactor buildings will increase, causing the contaminated water inside to flow out.
Maintaining the ice wall will cost over a billion yen a year, and the radiation exposure of workers involved in its maintenance is high. Meanwhile, there are no immediate prospects of being able to repair the basement damage in the reactor buildings at the crippled nuclear plant.
Nagoya University professor emeritus Akira Asaoka commented, “The way things stand, we’ll have to keep maintaining an ice wall that isn’t very effective. We should consider a different type of wall.”
In the meantime, TEPCO continues to be plagued over what to do with treated water at the plant. Tainted water is treated using TEPCO’s multi-nuclide removal equipment to remove 62 types of radioactive substances, but in principle, tritium cannot be removed during this process. Tritium is produced in nature through cosmic rays, and nuclear facilities around the world release it into the sea. The NRA takes the view that there is no problem with releasing treated water into the sea, but there is strong resistance to such a move, mainly from local fishing workers who are concerned about consumer fears that could damage their businesses. TEPCO has built tanks on the grounds of the Fukushima No. 1 plant to hold treated water, and the amount they hold is approaching 800,000 metric tons.
In mid-July, TEPCO Chairman Takashi Kawamura said in an interview with several news organizations that a decision to release the treated water into the sea had “already been made.” A Kyodo News report on his comment stirred a backlash from members of the fishing industry. TEPCO responded with an explanation that the chairman was not stating a course of action, but was merely agreeing with the view of the NRA that there were no problems scientifically with releasing the treated water. However, the anger from his comment has not subsided.
Critical opinions emerged in a subsequent meeting that the Ministry of Economy, Trade and Industry held in the Fukushima Prefecture city of Iwaki at the end of July regarding the decontamination of reactors and the handling of contaminated water. It was pointed out that prefectural residents had united to combat consumer fears and that they wanted officials to act with care. One participant asked whether the TEPCO chairman really knew about Fukushima.
The ministry has been considering ways to handle the treated water, setting up a committee in November last year that includes experts on risk evaluation and sociology. As of Aug. 15, five meetings had been held, but officials have yet to converge on a single opinion. “It’s not that easy for us to say, ‘Please let us release it.’ It will probably take some time to reach a conclusion,” a government official commented.
Japan’s Nuclear Regulation Authority has approved the completion of the remaining parts of the Fukushima nuclear power plant’s “ice wall” ground freeze beneath the station in order to prevent groundwater from entering the damaged reactor’s facilities, local media reported Tuesday.
MOSCOW (Sputnik) – The plan stipulates creating a 0.9 mile long barrier by circulating coolant of 30 degrees below zero in pipes buried around the building. The “ice wall” is expected to keep groundwater from entering the station and therefore prevent an increase in amounts of water contaminated by radioactive substances. Initially, the Nuclear Regulation Authority was concerned with the fact that if the whole wall was created, it would probably lead to a drastic decrease in water in the area around the station and cause leakages of contaminated water outside the damaged reactor’s building. Experts thus previously ruled to leave a 23-foot section of the wall unfrozen.
According to the NHK broadcaster, the Tokyo Electric Power Company (TEPCO), responsible for the project, claimed that the completion of the wall would not result in a sudden decrease of water levels, and even if it would, the company promised to take immediate measures. After considering the company’s position, experts allowed to complete the “ice wall.”
The broadcaster said that TEPCO will begin the remaining work on August 22, completing the soil freeze that first began in March 2016. It was also reported that after the works are completed, the Nuclear Regulation Authority would carefully assess the results and examine whether there have been any positive improvements in water contamination.
In 2011, a major earthquake triggered a tsunami that hit Japan’s Fukushima NPP and led to the leakage of radioactive materials and the shutdown of the plant. Following the incident, Tokyo shut down all the NPPs in Japan and began to restart them after introducing new security standards.
Mainichi Shimbun reporters visited the Fukushima No. 1 Nuclear Power Plant on July 27. While the working environment at the station has improved, plant operator Tokyo Electric Power Co. (TEPCO) still has a mountain of problems to tackle, such as removing melted nuclear fuel from the No. 1 to No. 3 reactors and treating contaminated water.