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U.S. Nuclear Cleanup Carries Major Risks
Roland Piquepaille writes "New Scientist reports in this pretty alarming article that there is a 50-50 chance of a major radiation or chemical accident during the cleanup of the dirtiest nuclear site in the U.S. There are indeed lots of things to clean at the Hanford complex in Washington state: 67 tons of plutonium and 190 million liters of liquid radioactive waste stored in underground tanks. A third of them, dating from the Cold War, have already leaked 4 million liters in the environment, contaminating the groundwater and a river. Meanwhile, officials at the DOE, who'll spend $50 billion between now and 2035 on this cleanup, seem less worried than the different specialists interviewed by New Scientist. Please read this overview for selected quotes from the article and from the Hanford site. You'll also find a slide from the DOE showing the timeframe for the cleanup."
Overview of Handford radioactive pollution issues
Summarizing...
From 1944-1972, Hanford released 740 kcuries of iodine-131, 200 kcuries of tritium, 19 Mcuries of krypton-85, 420 Mcuries of xenon-133, and many other radionuclides into the air, most during non-filtered or periods of early filters from 1944-1950. The biggest health risk is probably the iodine-131, rather than the noble gasses xenon and krypton. The iodine exposure was from contaminated milk, eating contaminated fruits and vegetables, and breathing contaminated air. Iodine is bio-concentrated in the thyroid gland, which can lead to tumors there.
Tritium was released mainly in 1949 through 1954. Also early on, a lot of particles of ruthenium radionuclides and plutonium were released.
Releases from cooling water and flushes of the reactors at Hanford (for creating plutonium for weapons) lead to water-borne exposure from zinc-65, arsenic-76, phosphorus-32, sodium-24 and neptunium-239. Eating fish and shellfish was the main way people were exposed to radiation from Hanford's reactors.
60 million gallons of highly radioactive waste from the chemical separations plants are stored in 177 underground tanks at Hanford. The tanks contain about 200 million curies of radioactivity. Over the years, more than 1 million gallons, containing over 100 kcuries of radioactivity, have leaked into the soil. At present, it is uncertain whether any of this waste has reached the groundwater.
Tritium is the most commonly found radionuclide in the groundwater at Hanford. Ruthenium-106, technetium-99 and iodine-129 are three of the other radioactive materials commonly found in Hanford's groundwater.
The separations plants required large amounts of water to process plutonium and this water became contaminated inside the plants. Hanford has estimated that over 440 billion gallons of these radioactive wastes were dumped into the ground.
Hanford also buried solid wastes in the soil. This waste contains nearly 5 million curies of radioactivity.