6 Juin 2013
June 5, 2013
by Akio Matsumura
Contaminated water is posing a new problem at the Fukushima site. Tepco must continue to cool the irradiated fuel rods, but has not devised a permanent and sustainable disposal process for the highly radioactive contaminated water that results. While they have a process that can remove much of the radiation from the water, some elements like tritium – a carcinogen – cannot be removed and is concentrating at magnitudes much higher than is legal. Tepco wants to spill the water into the Pacific Ocean in order to dilute the tritium levels to legal amounts, but fishermen skeptical of the power company oppose the move. Meanwhile, Tepco is storing the contaminated water in tanks. Unsurprisingly, those tanks are leaking (NYT). They admit they will eventually run out of space for the storage tanks.
Management of the contaminated cooling water has come to be the most demanding and dangerous issue that Tepco has faced since 2011.
According to the Japan Times (excerpted):
As of May 7, Tepco had routed 290,000 tons of radioactive water into some 940 huge tanks at the complex, but 94,500 tons remain inside the basement floors of the reactor buildings and other facilities.
Tepco must perpetually pour water over the melted cores of reactors 1, 2, and 3 via makeshift systems to prevent the fuel from melting and burning again.
But the cores’ containment vessels were damaged by the meltdowns, allowing the highly radioactive coolant water to leak and flow into the basements. The dangerous radiation levels have prevented workers from getting close enough to fully assess the damage, let alone start the decommissioning process.
Compounding the problem is some 400 tons of groundwater that is also entering the basements of the tsunami- and explosion-damaged buildings, mixing with the leaking coolant water.
Tepco has been operating a water-recycling system to drain the basements that is supposed to extract cesium before recirculating the water back to the reactors. But the added inflow of the groundwater is exacerbating the threat.
In response, all Tepco has been able to do is build more storage tanks.
What problems will the water eventually pose?
Tepco says there is a limit to how many tanks the complex can accommodate before the site runs out of storage space.
Tepco said it can boost storage capacity from 430,000 tons from this year to 700,000 tons by mid-2015 by clearing a forest and other space in the compound. The move is expected to buy them about three years’ time.
How Water Becomes Radioactively Contaminated
by Gordon Edwards, Ph.D.
(1) When nuclear fuel is used in a nuclear reactor or an atomic bomb, the atoms in the fuel are “split” (or “fissioned”) to produce energy. The fission process is triggered by subatomic particles called neutrons. In a nuclear reactor, when the neutrons are stopped, the fission process also stops. This is called “shutting down the reactor.”
(2) But during the nuclear fission process, hundreds of new varieties of radioactive atoms are created that did not exist before. These unwanted radioactive byproducts accumulate in the irradiated nuclear fuel — and they are, collectively, millions of times more radioactive than the original nuclear fuel.
(3) These newly created radioactive materials are classified as fission products, activation products, and transuranic elements. Fission products — like iodine-131, cesium-137 and strontium-90 — are the broken pieces of atoms that have been split. Activation products — like hydrogen-3 (“tritium”), carbon-14 and cobalt-60 — are the result of non-radioactive atoms being transformed into radioactive atoms after absorbing one or more stray neutrons. Transuranic elements — like plutonium, neptunium, curium and americium — are created by transmutation after a massive uranium atom absorbs one or more neutrons to become an even more massive atom (hence “transuranic,” meaning “beyond uranium”).
(4) Because of these intensely radioactive byproducts, irradiated nuclear fuel continues to generate heat for years after the fission process has stopped. This heat (“decay heat”) is caused by the ongoing atomic disintegration of the nuclear waste materials. No one knows how to slow down or shut off the radioactive disintegration of these atoms, so the decay heat is literally unstoppable. But decay heat does gradually diminish over time, becoming much less intense after about 10 years.
(5) However, in the early years following a reactor shutdown, unless decay heat is continually removed as quickly as it is being produced, the temperature of the irradiated fuel can rise to dangerous levels — and radioactive gases, vapors and particles will be given off into the atmosphere at an unacceptable rate.
(6) The most common way to remove decay heat from irradiated fuel is to continually pour water on it. Tepco is doing this at the rate of about 400 tons a day. That water becomes contaminated with fission products, activation products and transuranic elements. Since these waste materials are radiotoxic and harmful to all living things, the water cannot be released to the environment as long as it is contaminated.
(7) Besides the 400 tons of water used daily by Tepco to cool the melted cores of the three crippled reactors, another 400 tons of ground water is pouring into the damaged reactor buildings every day. This water is also becoming radioactively contaminated, so it too must be stored pending decontamination.
(8) Tepco is using an “Advanced Liquid Processing System” (ALPS) that is able to remove 62 different varieties of radioactive materials from the contaminated water — but the process is slow, removal is seldom 100 percent effective, and some varieties of radioactive materials are not removed at all.
(9) Tritium, for example, cannot be removed. Tritium is radioactive hydrogen, and when tritium atoms combine with oxygen atoms we get radioactive water molecules. No filtration system can remove the tritium from the water, because you can’t filter water from water. Released into the environment, tritium enters freely into all living things.
(10) Nuclear power is the ultimate example of the throwaway society. The irradiated fuel has to be sequestered from the environment of living things forever. The high-quality materials used to construct the core area of a nuclear reactor can never be recycled or reused but must be perpetually stored as radioactive waste. Malfunctioning reactors cannot be completely shut off because the decay heat continues long after shutdown. And efforts to cool a badly crippled reactor that has melted down result in enormous volumes of radioactively contaminated water that must be stored or dumped into the environment. No wonder some have called nuclear power “the unforgiving technology.”
Nine Medical Implications of Tritium-contaminated Water
by Helen Caldicott, M.D.
(1) There is no way to separate tritium from contaminated water. Tritium, a soft beta emitter, is a potent carcinogen which remains radioactive for over 100 years. It concentrates in aquatic organisms including algae, seaweed, crustaceans and fish. Because it is tasteless, odorless and invisible, it will inevitably be ingested in food, including seafood, over many decades. It combines in the DNA molecule – the gene – where it can induce mutations that later lead to cancer. It causes brain tumors, birth deformities, and cancers of many organs. The situation is dire because there is no way to contain this radioactive water permanently and it will inevitable leak into the Pacific Ocean for over 50 years or longer along with many other very dangerous isotopes including cesium 137 which lasts for 300 years and causes very malignant muscle cancers –rhabdomyosarcomas, strontium 90 which also is radioactive for 300 years and causes bone cancers and leukemia, amongst many other radioactive elements.
(2) All cancers can be induced by radiation, and because much of the land in Fukushima and beyond is contaminated, the food – tea, beef, milk, green vegetables, rice, etc. – will remain radioactive for several hundred years.
(3) “Cleanup” is a misnomer, radioactively contaminated soil, timber, leaves, and water cannot be decontaminated, just possibly moved to another site there to contaminate it.
(4) Incineration of radioactive waste spreads the cancer-inducing agents to other areas including non-contaminated areas of Japan.
(5) Cancers have a long incubation period – 2 to 80 years after people eat or breath radioactively contaminated food or air.
(6) The IAEA says that decommissioning of these reactors will take 50 to 60 years and some people predict that this mess will never be cleaned up and removed.
(7) Where will Japan put this highly radioactive melted fuel, fuel rods and the like? There is absolutely no safe place to store this deadly material (that must be isolated from the exosphere for one million years according to the US EPA) on an island that is riven by earthquakes.
(8) As these radioactive elements continually seep into the water and the ocean and are emitted into the air the incidence of congenital deformities, cancer and genetic defects will inevitably increase over time and into future generations.
(9) Children are 10 to 20 times more sensitive to the carcinogenic effects of radiation than adults (little girls are twice as sensitive as boys) and fetuses are thousands of times more sensitive – one X ray to the pregnant abdomen doubles the incidence of leukemia in the child.