By Steven Starr, MT (ASCP), PSR Senior Scientist
The destruction of the Fukushima Daiichi nuclear power plant in March 2011, caused by an earthquake and subsequent tsunami, resulted in massive radioactive contamination of the Japanese mainland. In November 2011, the Japanese Science Ministry reported that long-lived radioactive cesium had contaminated 11,580 square miles (30,000 sq km) of the land surface of Japan.[i] Some 4,500 square miles—an area almost the size of Connecticut—was found to have radiation levels that exceeded Japan’s allowable exposure rate of 1 mSV (millisievert) per year.
About a month after the disaster, on April 19, 2011, Japan chose to drastically increase its official “safe” radiation exposure levels[ii] from 1 mSv to 20 mSv per year – 20 times higher than the US exposure limit. This allowed the Japanese government to downplay the dangers of the fallout and avoid evacuation of many badly contaminated areas.
However, all of the land within 12 miles (20 km) of the destroyed nuclear power plant, encompassing an area of about 230 square miles (600 sq km), and an additional 80 square miles (200 sq km) located northwest of the plant, were declared too radioactive for human habitation.[iii] All persons living in these areas were evacuated and the regions were declared to be permanent “exclusion” zones.
The precise value of the abandoned cities, towns, agricultural lands, businesses, homes and property located within the roughly 310 sq miles (800 sq km) of the exclusion zones has not been established. Estimates of the total economic loss range from $250[iv]-$500[v] billion US. As for the human costs, in September 2012, Fukushima officials stated that 159,128 people had been evicted from the exclusion zones, losing their homes and virtually all their possessions. Most have received only a small compensation to cover their costs of living as evacuees. Many are forced to make mortgage payments on the homes they left inside the exclusion zones. They have not been told that their homes will never again be habitable.
Radioactive cesium has taken up residence in the exclusion zone, replacing the human inhabitants. Cesium-137 has a half-life of 30 years, and since it takes about 10 half-lives for any radionuclide to disappear, it will maintain ownership of the exclusion zone for centuries.
Once a large amount of radioactive cesium enters an ecosystem, it quickly becomes ubiquitous, contaminating water, soil, plants and animals. It has been detected in a large range of Japanese foodstuffs, including spinach, tea leaves, milk, beef, and freshwater fish up to 200 miles from Fukushima. Radioactive cesium bioaccumulates, bioconcentrates, and biomagnifies as it moves up the food chain. Routine ingestion of foods contaminated with so-called “low levels” of radioactive cesium has been shown to lead to its bioaccumulation in the heart and endocrine tissues, as well as in the kidneys, small intestines, pancreas, spleen and liver. This process occurs much faster in children than in adults, and children are many times more susceptible than adults to the effects of the ionizing radiation their internal organs are then exposed to.
Decontamination in the exclusion zones is proving futile. Efforts to clean up highly contaminated areas are generally failing because melting snow and rainwater run off the contaminated hills and return to recontaminate homes and land. Diversion ditches have failed to stop the process. Areas significantly contaminated with radioactive cesium and other long-lived radionuclides can no longer sell and export agricultural crops.
In addition to its effects on land, the Fukushima disaster produced the largest discharge of radioactive material into the ocean in history.[vi] Fifteen months after 733,000 curies of radioactive cesium were pumped into the Pacific, 56 percent of all fish catches off Japan were found to be contaminated with it.[vii] Fishing continues to be banned off the coast of Fukushima, where 40 percent of bottom dwelling fish (sole, halibut, cod) were recently found to have radioactive cesium levels higher than current Japanese regulatory limits.
Meanwhile, the destroyed Fukushima reactors and spent fuel ponds, which hold huge quantities of radioactive waste, are far from being stabilized. Reactors #1, #2 and #3 every day discharge radioactive gases that emit a billion becquerels of radiation. The uranium cores of reactors 1, 2 and 3, which completely melted down and then melted through the bottom of the steel reactor vessel,[viii] will continue to produce enormous amounts of radiation and heat for many years. Every day, ten tons of seawater is poured upon each of the melted cores; the water becomes intensely radioactive and then rapidly leaks out of the containment4 into the adjacent turbine building. It is then pumped through an expensive cooling system that traps the radioactivity in filters the size of small cars, which become highly radioactive and are being placed in a nearby field. Fifty million gallons of intensely radioactive water have already been collected and stored on site.[ix] Thousands of additional radioactive gallons continue to accumulate daily, and the jury-rigged pipe system connecting the storage tanks remains at risk, should another large quake strike the area.
Other forms of maintenance are also required to avoid potentially catastrophic radiation-releasing events. The intense gamma radiation from the melted fuel causes the seawater to disassociate into hydrogen and oxygen gas. In order to prevent further hydrogen explosions, which have already destroyed the buildings housing reactors 1, 3 and 4, nitrogen gas must be continually pumped into the leaking containment vessel. This process must continue for another six or seven years. Reactor building #4 was severely damaged by the earthquake and a massive hydrogen explosion. It holds a spent fuel pool with 1,532 nuclear fuel assemblies, which contain about 10 times more radioactive cesium than was released by the Chernobyl disaster.[x] Should building 4 collapse, its fuel pool would lose its cooling water, and the gamma radiation from the exposed fuel assemblies would then be immediately lethal to anyone within 300 feet. It would be impossible to access the site, including the common pool that contains 6,000 fuel assemblies, which is located 50 feet from building 4.
Thus the collapse of building 4 could lead to the release of many times more radiation than has already escaped from Fukushima. This would leave much of Japan uninhabitable and would constitute a global disaster.
Tokyo Power and Electric Company (TEPCO, the owner of the Fukushima Daiichi nuclear power plant) is pursuing a timetable that will require about two and a half years to safely removed the spent fuel assemblies from building 4. In August, TEPCO stated that reactor 4 building can withstand a quake in the upper 6 magnitude.[xi] Let’s hope so, because experts forecast that there is a high probability of an earthquake of this magnitude or greater occurring at Fukushima.[xii] It is an open question as to whether or not building 4 could withstand such an event.
There are 23 nuclear reactors of the same design as those at Fukushima now operating in the US. US spent fuel pools contain many times more spent fuel than the spent fuel pool at reactor building 4 in Fukushima Daiichi.[xiii] It is past time to shut these reactors down and place their spent fuel rods in dry-cask storage, which is not vulnerable to a loss-of-coolant disaster.[xiv]
[i] The Asahi Shimbun. “Radioactive Cesium Spread as far as Gunma-Nagano Border.” The Asahi Shimbun.12 Nov. 2011. Web. 6 Nov. 2012.
[ii] Committee to Assess Health Risks from Exposure to Low Levels of Ionizing Radiation, National Research Council. Health Risks from Exposure to Low Levels of Ionizing Radiation: BEIR VII Phase 2. Washington, DC: The National Academies Press, 2006. Web.
[iii] World Nuclear News. “Another evacuation order lifted.” World Nuclear News . 15 Aug. 2012. Web. 6 Nov. 2012.
[iv] NewsonJapan.com, “Fukushima Cleanup Could Cost up to $250 Billion” NewsOnJapan.com. 6 Nov. 2012
[v] Gundersen, Arnie & Caldicott, Helen. “The Ongoing Damage and Danger at Fukushima.” Fairewinds Energy Education. Web. 6 Nov. 2012.
[vi] Institut de Radioprotection y de Sureté Nucléaire. Web. 26 Oct. 2012.
[vii] Roslin, Alex. “Post-Fukushima, Japan’s Irradiated Fish Worry B.C. Experts.” Straight.com 19 Jul. 2012. Web. 6 Nov. 2012
[viii] Nuclear Information & Resource Service. “Nuclear Crisis in Japan.” Web. 6 Nov. 2012.
[ix] Yamaguchi, Mari. “Fukushima Nuclear Disaster: Plant’s Contaminated Water Storage Running Out Of Space.” The Huffington Post. 25 Oct. 2012. Web. 6 Nov. 2012.
[x] Akio Matsumura. “Correspondence on the New Photo of Reactor Unit No. 4 at Fukushima.” Akio Matsumura. 21 Feb. 2012. Web. 6 Nov. 2012.
[xi] The Asahi Shimbun. “TEPCO: No. 4 Reactor Building Can Withstand 6-Plus Intensity Quake.” The Asahi Shimbun. 31 Aug. 2012. Web. 6 Nov. 2012.
[xii] ScienceDaily. “Fukushima at Increased Earthquake Risk, Scientists Report.” ScienceDaily. 13 Feb. 2012. Web. 6 Nov. 2012.
[xiii] Alvarez, Robert. “Spent Nuclear Fuel Pools in the U.S.: Reducing the Deadly Risks of Storage.” Institute for Policy Studies. May 2011.
[xiv] Alvarez, Robert et al. “Reducing the Hazards from Stored Spent Power-Reactor Fuel in the United States.” Science and Global Security. 11 (2003): 1-51.