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Model | Home Home Search Primary Menu Skip to contentWell-nighInFORMal E-News InFORM Scientists InFORMal Scientists InFORMal Science Photos Partners InFORM Monitoring InFORMal E-News Methods Citizen Science Gamma Spectroscopy Marine Biota Monitoring Methods for Other Radionuclides (WHOI CMER) Biota Oceanic Coastal Archived Results Radiation Research By Location Japan Fukushima NW Pacific N Pacific NE Pacific British Columbia North America Chernobyl By Sample Type Algae Atmospheric Human Marine Life Model Plants & Fungi Seawater Sediment By Isotope Cesium Iodine Plutonium Polonium Potassium Strontium Tellurium Uranium Xenon Presentations & Media Presentations Media Interviews Resources InFORMing Research FAQ Radiological Monitoring at the Radiation Protection Bureau of Health Canada IAEA Inter-laboratory Comparison Report 2014-2016 Official IAEA Report on the Fukushima DaiichiWreckingUNSCEAR 2017 Report on Levels and Effects of Radiation Exposure Methods for Other Radionuclides (WHOI CMER) Safety lessons learned from Fukushima: Part 1 – National Acadamies Report Safety lessons learned from Fukushima: Part 2 – National Acadamies Report Health Canada Observations Post-Disaster Canadian Radiological Monitoring Network Naturally Occurring Radioactive Materials Guidelines Search for: Category Archives: Model Fukushima, Model, Peer Reviewed, Plutonium, Uranium Plutonium Inventories at Fukushima Dai-ichi Nuclear Power Plant and Mixed Oxide (MOX) Fuel at Unit 3 November 25, 2014 fukushimainform Leave a scuttlebutt By Jay T. Cullen The purpose of this post is to provide estimates of the plutonium (Pu) isotopes present at the Fukushima Dai-ichi nuclear power plant (NPP) at the whence of the disaster in March 2011. The post is part of an ongoing effort to communicate facts well-nigh Fukushima obtained through scientific study of the impact of the meltdowns on the environment. Comments on this site and in other public forums highlight the fact that Unit 3 at the NPP was urgent mixed oxide (MOX) fuel at the time of the wrecking which, considering it is enriched in Pu, suggests that these releases are potentially increasingly harmful. Here I report estimates of Pu present in the reactors (Units 1, 2 and 3) and spent fuel pools (Units 1-4) at the site based on burnup calculations.Consideringfission of low enriched uranium (LEU) fuel produces Pu isotopes during operation there was a significant value of Pu on site in Units 1-4. During extended operation a MOX fuel urgent reactor can produce multiple times the Pu of LEU but this was not so at the time of the Fukushima meltdowns. The value of spare Pu present due to Unit 3’s MOX fuel is small compared to the other reactor cores and the inventory of the spent fuel pools. The differences between environmental impact of MOX versus LEU reactor cadre meltdown in this specimen are small. Estimates of the release of Pu isotopes from Fukushima, based on measurements of air, soil and water suggest 100,000 fold less was unconcentrated to the environment compared to Chernobyl and 5,000,000 fold lower than releases from nuclear weapons testing in the 20th century. Continue reading Plutonium Inventories at Fukushima Dai-ichi Nuclear Power Plant and Mixed Oxide (MOX) Fuel at Unit 3 → Advertisements 238-U239-PuFukushimaMeltdownRadiationRadionuclidesReactorReleaseSpent fuel Japan, Marine Life, Model, NW Pacific, Peer Reviewed, Strontium Release, Dispersion and Fate of Radioactive Strontium From Fukushima in the Northwest Pacific Ocean October 3, 2014 fukushimainform Leave a scuttlebutt By Jay T. Cullen The purpose of this diary is to summarize recent models and measurements of the release of strontium-90 (90-Sr, half life 28.8 yr) to the ocean resulting from the triple meltdowns at the Fukushima-Daiichi nuclear power plant in March 2011. This post is part of an ongoing series aimed at understanding the impact of the disaster on the North Pacific Ocean and residents of the west tailspin of North America. 90-Sr is a beta-emitting element that is a radiological health snooping given its relatively long half life and similar chemistry to the nutrient calcium (Ca). Previous peer-reviewed work indicate that releases of 90-Sr were well-nigh 30-10,000 fold less than 137-Cs and similar to the release of 90-Sr from the Chernobyl disaster in 1986 and well-nigh 600-fold lower than the releases from atmospheric weapons tests that peaked in the mid-1960’s. Given maximal release rates without the disaster, modeled activities of 90-Sr in the marine foodweb and in fish that finance for bioconcentration and unifying predict maximal dose rates from Fukushima to human consumers three orders of magnitude less than doses owing to the presence of 137-Cs in marine products and thus well unelevated maximum dose limits thought to be detrimental to public health. Continue reading Release, Dispersion and Fate of Radioactive Strontium From Fukushima in the Northwest Pacific Ocean → 90-SrBioaccumulationDispersionFishFukushimaHealth RiskJapanMaderichModelNW PacificSeafood Cesium, Model, N Pacific, NE Pacific, NW Pacific, Peer Reviewed Authors Lower Fukushima Cesium in North Pacific By Order of Magnitude September 21, 2014 fukushimainform Leave a scuttlebutt By Jay T. Cullen Introduction One of the goals of the InFORM project is to make measurements of radionuclides in the North Pacific Ocean to determine maximum activities that will determine impacts on the marine ecosystem and residents of the west coast. The purpose of this post is to bring to the sustentation of readers a recently published correction to a prominent model that predicts the worriedness of Fukushima derived Cesium-137 (137-Cs, half life ~30 years) in seawater of the North Pacific. The diary is part of an ongoing series aimed at discussing research addressing the impact of the Fukushima nuclear disaster on the health of the North Pacific Ocean and inhabitants of North America’s west coast. Predictions of a model by Rossi and colleagues published in Deep-Sea Research in 2013 of the incubation of the plume of seawater contaminated by the Fukushima triple meltdowns are an order of magnitude too high. Rather than a range of ~1-30 Bq/m^3 reported previously maximum activities off the west tailspin of North America are likely to be ~3 Bq/m^3 or well-nigh increasingly than 25 times lower than maximum activities measured in the Pacific in the mid-20th century resulting from atmospheric weapons tests. These activities are not likely to represent significant radiological health risks to the North Pacific ecosystem or residents of the North American west coast. A paper by Rossi et al. (2013) used a Lagrangian model to predict the temporal and spatial incubation of the seawater plume contaminated by the Fukushima nuclear disaster whence in March 2011. The model predicted a range of 10-30 Bq/m^3 137-Cs in waters off the tailspin of North America at 49 degrees North latitude as demonstrated in the icon shown below: Activities of 137-Cs predicted by the Rossi et al. (2013) model on the continental shelves of North America at two latitudes and off Hawaii over time. This model predicted higher maximum 137-Cs activities in seawater in the North Pacific compared with a similar model published by Behrens et al. (2012) that had maximum activities off of North America reaching only ~1-2 Bq/m^3. Recently, without comments from Professor Michio Aoyama of Japan, Rossi and colleagues recognized an error in their model and have published a correction to their 2013 study here. The error resulted in a factor of 10 overestimation of maximum activities of 137-Cs in the Pacific such that maximum 137-Cs off N. America will likely be between 1 and 3 Bq/m^3. The corrections to the model do not stupefy the conclusions of the study and results from the 2013 study are easy scaled to the increasingly well-judged values given the Langrangian tideway used by the authors in the original work. The icon unelevated shows the time incubation of the plume at various latitudes withal the international stage line and compares the model output with measurements made by Aoyama et al. (2013) withal the international dateline at well-nigh 40 degrees N in 2012. Activities of 137-Cs predicted by the Rossi et al. model withal the international dateline in the N. Pacific over time at various latitudes. The factor of 10 lower worriedness correction largest agrees with the Behrens et al. (2012) modeling study and measurements of 137-Cs in seawater made by Japanese and North American scientists. Maximum activities of ~1-3 Bq/m^3 as the heart of the contaminated plume reaches the North American tailspin in the coming 2 year period are roughly 25-fold lower than 137-Cs activities in the North Pacific circa 1960 resulting from atmospheric weapons testing. Therefore, it is unlikely that 137-Cs activities of 3 Bq/m^3 or associated radionuclides released at lower total activities from Fukushima will represent significant health risks to the North Pacific ecosystem. Ongoing monitoring of radionuclide activities in the North Pacific is required to ground-truth models of Pacific Ocean diffusion and plume incubation and to provide the weightier information to determine likely impact to residents of North America. 137-CsAoyamaBehrensContaminationCorrectionHealth RiskModelN PacificPlumePrediction Cesium, Model, N Pacific, Peer Reviewed Misunderstanding Ocean Transport Models of the Fukushima Radionuclide Plume in the Pacific August 16, 2014 fukushimainform 9 Comments by Jay T. Cullen Introduction This post is part of an ongoing series that endeavors to provide useful and well-judged information about: 1) the fate of Fukushima derived radionuclides in the Pacific Ocean, and, 2) the impact of these radionuclides on the marine ecosystem and the west tailspin of North America. The purpose of this diary is to yank sustentation to a number of poorly researched posts well-nigh a recently published study (unfortunately this study is overdue a publisher pay-wall) in a Chinese periodical that predicts a well-matured plume of radioactive elements from Fukushima arriving on the west coast. It is an unfortunate but worldwide example of how news team sites can misinterpret the results of a scientific study and misinform the public. What models can and cannot say well-nigh the Fukushima plume The study in question by Fu and co-workers published in thePeriodicalof Ocean University of China in 2014 (behind pay-wall unfortunately) is wholly incapable of describing the policies of dissolved radionuclides in the plume that is now arriving on the west tailspin of North America. From the paper the authors themselves state in the methods that: “In the study, the radioactive pollutant in the ocean is treated as a mixture of multiple Lagrangian particulates, and each particulate represents a radioactive element. The particulates can move in both horizontal and vertical directions, but cannot longish and mix with surrounding seawater.” What this ways is that rather than stuff unliable to mix and longish (or waste or sink without rhadamanthine associated with particles) the radionuclides are treated as neutrally buoyant drifters. The model, therefore, profoundly overestimates the concentrations of radionuclides reaching the west tailspin of North America in the plume. For those interested in models using well-judged physics that will indulge for an well-judged prediction of radionuclide concentrations consult the pursuit studies: Behrens et al. (2012) and Rossi et al. (2013) (behind pay-wall) Snapshot of the high-resolution (0.1°) model field, from Behrens et al. taken at the end of the tracer injection period (end of April, model year 0): shading indicates the thickness of the surface mixed layer (in m); contouring illustrates the surface velocity field indicated by local stream lines and unmistakably identifies the upper velocity Kuroshio and Kuroshio extension. The Behrens et al. study is open-access while the Rossi et al. study is not. Measurements taken in the North Pacific by Canada’s Department of Fisheries and Oceans and InFORM team member Dr. John Smith indicate that the Rossi et al. study predicts the inrush time of the plume on the west tailspin but overestimates the worriedness of the Fukushima derived radionuclide 137-Cs. Behrens et al. predict a too late time of inrush but with lower activities that towards to increasingly realistic. It important to note that these models siphon the own simplifications and assumptions (e.g. see section 3.4 Caveats of the Behrens et al. (2012) study) and that recent measurements suggest that some of the Fukushima plume is stuff sparse to the south rather than to the east in the Pacific (e.g. Kumamoto et al. (2014) open-access; increasingly on this study in a forthcoming post). Articles that misplace the conclusions of the Chinese study are a good example of poor reporting on an important subject. The example here was originally spawned by Energy News who have a history of inaccurate reporting on Fukushima and then propagated through the web by uncritical followers of the site. BehrensFuFukushimaKumamotoMixingModelModelsN PacificPlumeRossi View Fukushima-InFORM-257383817784613’s profile on FacebookView @FukushimaInFORM’s profile on TwitterView UCRqxVIr3s5Yc-djXahyBunA’s profile on YouTube Recent Posts Voyage Reflections Friday the 13th was the Luckiest Day Ever Into the Storm Advertisements Funded by Create a self-ruling website or blog at WordPress.com. Post to Cancel Privacy & Cookies: This site uses cookies. By standing to use this website, you stipulate to their use. To find out more, including how to tenancy cookies, see here: Cookie Policy