Graphic Account of the Fukushima Tritium Releases Now Underway: Science.

[NNadir]

This news item appeared this week in the prominent scientific journal Science referring to the big bogeyman at Fukushima, and the much discussed release of tritiated water which will take place over the next 30 years.

The risks of radioactive wastewater release

Jim Smith , Nigel Marks, AND Tony Irwin Science 5 Oct 2023 Vol 382, Issue 6666 pp. 31-33

I'm logged into my account, and am not sure whether the article is open sourced, but I'll excerpt and produce the graphic promised in the title of this post.

If you're looking for a scare story to elevate your selective attention on a planet that burst into flame this summer because of the accumulation of the dangerous fossil fuel waste carbon dioxide, do not read on, but spend your time in insipid agonizing, along with the fossil fuel salespeople here and elsewhere trying to rebrand fossil fuels as "hydrogen" and other people engaged in the ennui and excuses for perpetuating the use of fossil fuels and fossil fuel dependent unreliable junk, specifically wind and solar.

A Giant Climate Lie: When they're selling hydrogen, what they're really selling is fossil fuels.

The subtitle:

The wastewater release from the Fukushima Daiichi nuclear plant is expected to have negligible effects on people and the ocean

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I'm fairly certain that the coal, oil, and gas burned to power computers by people carrying on about the tritium releases at Fukushima will kill more people than radiation at Fukushima, including those released during the natural disaster that destroyed the reactors (and a city) has ever or ever will.

Excerpts from the news item:

In 2011, the east coast of Japan suffered an earthquake and tsunami that resulted in the meltdown of three of the reactors at the Fukushima Daiichi nuclear plant. This led to an uncontrolled release of large amounts of radioactive material to the surrounding land and to the Pacific Ocean. More than 10 years later, new releases of radioactive wastewater to the Pacific Ocean from the Fukushima plant have started. The historical ocean contamination from Fukushima included large quantities of long-lived radioactive cesium-137 (137Cs), so there is widespread concern over these new wastewater discharges. However, these releases will result in much lower total radiation doses to people and aquatic ecosystems than the contamination caused by the accident (1–3). Furthermore, aquatic ecosystems, including those around the Chernobyl disaster site, have been shown to be remarkably resilient to radiation (4–7). Thus, the new Fukushima releases are not expected to cause substantial effects on seafood consumers or the marine ecosystem.

The highest-activity radioactive contaminant in the Fukushima wastewater is tritium (3H), in the form of tritiated water (HTO). This molecule cannot be separated from the wastewater because its chemical behavior is the same as that of nonradioactive water. Like other radionuclides [such as natural carbon-14 (14C) and anthropogenic 137Cs], which emit high-energy γ rays and β particles when they decay, tritium can have biological effects on organisms, particularly DNA damage (8). But tritium’s radiotoxicity by ingestion is very low compared to that of these other radionuclides owing to its very weak β emission and relatively short retention time in the body. Therefore, it is common practice for nuclear facilities worldwide to discharge wastewater containing HTO into the sea (see the figure).

The La Hague nuclear facility in France annually discharges ∼10,000 terabecquerels (1 TBq = 1012 Bq; the becquerel is an amount of a radioactive element that produces one decay per second) of HTO into the English Channel, with annual discharges during 1996–2016 ranging between 8000 and 12,000 TBq (9). Radiation doses to people (measured in sieverts and defined as the amount of energy deposited in tissue, taking account of the response of human biology to different radiation types) from the release of HTO from La Hague are low [less than 0.01 microsieverts per year (μSv/year) (9), which compares with the 1000 μSv/year recommended limit for members of the public from nuclear site releases (2)], and no environmental impacts have been found or are expected...

I promised a graphic in the title of this post, here it is:




The caption:

Tritium from the Fukushima Daiichi releases in context
Radioisotopes, both naturally occurring and anthropogenic, exhibit different levels of radiotoxicity [based on (15)]. Tritium has a small dose coefficient mainly because its radiation is weak. In the Pacific Ocean, tritium contributes far less total radioactivity than naturally occurring radioisotopes. The planned annual release of tritium from Fukushima Daiichi is much lower than many releases from elsewhere, and the predicted annual radiation doses to local seafood consumers are much smaller than other sources of radiation.

It demonstrates that the radioactivity of the ocean is dominated by the naturally occurring essential element potassium, followed by the congener of potassium, naturally occurring rubidium (which follows potassium biochemically), and finally, the vast resources of naturally occurring uranium found in ocean water as part of the uranium cycle from the planetary mantle that has existed on this planet since the evolution of oxygen in the atmosphere billions of years ago.

Tritium has a relatively short half life, 12.26 years, and ultimately will come into secular equilibrium with the release rates, at which it is decaying at the same rate as it is added. In thirty years about 18% of the tritium released into the oceans and retained in the tanks not yet emptied will still be present, the rest having decayed to the rare stable isotope helium-3.

The highest environmental concentration of tritium in the environment actually took place before the commercial nuclear industry became serious, in 1963, as a result of atmospheric nuclear testing, when the concentrations were many orders of magnitude than they are now. (If interested, one can look it up.) About 3.4% of that tritium, with which everyone on the planet has lived their lives, their entire lives if born after 1963, still remains in the environment.

A final excerpt from the article:

Concerns have been expressed about biomagnification— the increased concentration of pollutants in organisms—of tritium and its potential detrimental effects on marine life, but these concerns do not correctly reflect the risk. If, as planned, tritium is released in the form of HTO, it cannot biomagnify because its biological uptake and distribution follow that of the greater mass of water (13), which does not biomagnify. This lack of biomagnification is due to the chemical similarity of HTO and H2O, which means that the 3H/1H ratio remains essentially unchanged in chemical and biological processes (13). Indeed, this is the very reason that HTO cannot be separated from ordinary water by Fukushima’s water treatment facility. Tritium can be retained longer in organic molecules (and thus in organisms) as organically bound tritium (OBT) (8) when HTO is digested by aquatic organisms. But even assuming long exposure times, the radiation dose rates are vanishingly small.

The authors of this article are Australian nuclear engineers. Nuclear engineers are a class of people who have to put up with this kind of selective attention crap, diverting their attention from what should be their main task, saving what is left to be saved in the world, and restoring what can be restored.

Have a pleasant Sunday.