May 11, 2013
The wastewater build-up problem at Fukushima Daiichi increases with every day that passes. After Cesium-stripping some 850 tons of raw wastewater per day, about 450 tons is used for cooling of the damaged fuel cores in units #1, 2 &3. The remainder is stored. Thus, the amount sent to storage increases by about 400 tons per day. Currently, there is more than 300,000 tons of Cesium-depleted water in storage. Tokyo Electric Company is testing a system, called ALPS, to remove all but one of the 62 isotopes that remain. The one residual radioactive isotope, Tritium, cannot be removed by ALPS because it is actually Hydrogen that is integral to the water molecule itself. The radioactive level of the Tritium in the stored wastewaters is about 100 Becquerels per milliliter. (ANS) Because of the Tritium, it is unlikely that Tepco will be allowed to discharge the ALPS-treated water to the sea and resolve the build-up problem. Why? Because local fisheries won’t agree to let it happen due to radiation fears and rumors that continually hurt the fishing business all along the Tohoku coastline. Further, based on the Asian-Pacific outcry following Tepco’s release of 11,500 tons of mildly radioactive water to the sea on April 4, 2011, it is likely a similar outcry will occur. Tokyo doesn’t want to go through that political problem again.
What would happen to the environment if Tepco did discharge the Tritiated water into the Pacific? Let’s look at the numbers. Tritium is a naturally-occurring radioactive isotope found in all water systems of the world. Tritium is produced in the upper atmosphere when cosmic rays strike nitrogen-based molecules in the air. (EPA) The Pacific Ocean naturally contains a total Tritium activity level of 370,000 Terabecquerels. (ISU) One Terabecquerel equals one trillion radioactive disintegrations per second. In addition, Tritium is a Beta radiation emitter, which is one of the two least-penetrating types of radioactivity. Plus, Tritium’s Beta particle is one of the weakest in all of nature. The half-life of tritium is 12.5 years, so it lasts a long time. Mother Nature’s natural build-up mechanism for Tritium balances with the radioactive decay, keeping the Tritium levels in the Pacific relatively constant.
As mentioned earlier, the stored wastewaters at Fukushima Daiichi contain a Tritium activity of about 100 Becquerels per milliliter. Tepco says there is nearly 325,000 tons of Cesium-stripped water now in storage. That’s a lot of milliliters – just under half a trillion milliliters, in fact. Thus, by multiply in 0.4 trillion by 100, we find the total Tritium activity of the wastewaters now stored at F. Daiichi is about 40 Terabecquerels. What would this added Tritium do to the Pacific if Tepco dumps all of it after decontamination with their ALPS system? It would increase the Tritium level of the Pacific by one one-hundredth of one percent…one part in ten thousand! Instead of 370,000 terabecquerels of Tritium, the Pacific would hypothetically contain 370,040 Terabecquerels. In point of fact, the increase would be barely detectible using the most sensitive monitoring technology known to mankind. It would be virtually indistinguishable from the Pacific’s natural concentration variations.
In other words, the dumping of all the post-ALPS Tritiated water from F. Daiichi directly into the Pacific would do nothing. That’s right – nothing.
Tritium is very difficult to remove from water. It is a slow, expensive process. Removing the Tritium will require keeping the hundreds of thousands of tons of Tritiated wastewaters in storage for additional months, if not years. In the end, what good would it do to remove the Tritium? It would be a good public relations move, to be sure. It would be a good political move, too. But, as we can see, it would not be a move dictated by the numbers. It would not be a move based on rationality and reason. While it would be socially and politically expedient, it would probably not avoid negative Press. Already, antinuclear voices in Japan say they will try and stop Tepco from discharging the waters to the sea, even if completely stripped of every last radioactive atom. Why? Antinuclear groups say they will take all action necessary to bar a release even if the Tritium were also removed because the water would have been previously radioactive and unacceptably “tainted”. No matter what Tepco ultimately does, it will get bad Press. It’s unavoidable.
Tepco will probably not be allowed to make this technically-innocuous discharge because of international politics, an antinuclear Press, and public fear of radiation. Because of Tritium, Tepco’s wastewater build-up will continue unabated and produce countless negative news reports into the foreseeable future.
What’s wrong with this picture?
References:
1. ANS – Fukushima Daiichi: ANS Committee Report; Section IV.B., Current Status; June, 2012. http://fukushima.ans.org/report/cleanup
2. EPA – Tritium: Where does tritium come from?; US Environmental Protection Agency; April 24, 2012. http://www.epa.gov/radiation/radionuclides/tritium.html#where
3. ISU – Natural Radioactivity in the Ocean; “Radioactivity in Nature”; Idaho State University: Radiation Information Network. http://www.physics.isu.edu/radinf/natural.htm
