Diluting nuclear waste
Diluting an amount of radioactive substance with an infinite amount of non-radioactive material will dilute the radioactivity of the mixture to nearly the natural levels and make the the radioactive waste nearly as harmless as the diluting materials. How sound is this view? Looking closer it turns out to be another fallacy in the nuclear world:
• Evidently diluting infinitely is not feasible. That means that the mixture always will be much more radioactive than the pristine material. In practice the radioactivity levels might be high.
• Nuclear waste contains a large number of different radionuclides and many of them are very dangerous, even in low concentrations. The radioisotopic composition of diluted waste is completely different from naturally occurring weakly radioactive materials. What counts are the types of radionuclides in the waste and their biological behaviour.
• It is a misconception to think that naturally occurring radioactivity would be harmless. Uranium-bearing rock, for instance, contains a number of very dangerous radionuclides, such as polonium-210. In addition to their radiotoxicity these radionuclides are chemically very toxic [more i18].
Increasing health risks
Larger waste volume increase the chances humans will come into contact with that waste or that it will enter the food chain. This may raise ethical questions like: What would be more acceptable to individuals: a small chance of ingesting 100 lethal doses or a hundred times greater chance of ingesting one lethal dose?
Radioactive waste is generally classified low-level waste (LLW) when the gamma radiation measured outside of the waste container is below a certain level, so much that the exposure of workers handling the waste containers is kept below a given standard. The radiation level is not unambiguously defined and may be different from one country to another. Below a certain gamma radiation level the waste is classified as non-nuclear waste and safe to be released into the public domain, for example uranium mining waste [more i18]. The standards are sensitive to economic priorities [more i26].
Why are these standards not the same in all countries? On which scientific grounds and empirical data are the standards of 'low-level' and 'safe' based?
Are these standards valid for the general public, in case of chronic exposure to 'low-level' and 'safe' nuclear waste?
Do these standards incorporate the health risks posed bythe widely different radionuclides which may be present in the waste, including the barely detectable ones, such as tritium and carbon-14?
Who monitors and controls the regulations? How does the classification of radioactive wastes work out in practice, in all countries with nuclear power?
Chronic exposure to doses of radioactivity which are 'low' according the current official standards have serious health effects with the exposed people, as has been proven by large epidemiological studies in Germany and France.
Military nuclear facilities in the USA and other countries did dilute nuclear wastes by soil in the past, simply by letting the liquid wastes leak into the ground and ground water, via storage ponds or otherwise. In the former Sovietunion large lakes and rivers are so heavily contaminated that the surrounding regions became inhabitable. Up until the 1990s large amounts of nuclear wastes, including complete reactors, have been dumped into the sea: diluting by sea water.
The amounts of radioactivity in the waste from cicil nuclear installations may be a factor 100 larger than from military nuclear activities. Diluting radioactive wastes by air and (sea) water is common practice in the civil nuclear industry. Large amounts of radioactive materials are routinely discharged into the human environment by reactors. Reprocessing plants are discharging even larger amounts of radionuclides, including fission products and actinides. This practice is an essential part of their 'waste reduction' policy. Not by chance the reprocessing plants of France (La Hague) and the UK (Sellafield and the now closed Dounreay facility) are situated at the sea shore [more i17, i19, i31].
The consequences of this practice are observable. Some nuclides cumulate in the food chain, for example iodine in seaweed. In the sea off the coast of Norway lobsters have been catched with a significant plutonium content. Seafood is rarely or never checked on its radioactivity content.
Decommissioning and dismantling waste
Massive amounts of radioactive waste will result from dismantling nuclear power plants and reprocessing plants [more i20]. The radioactivity content of the ruble and scrap resulting from contamination and neutron radiation will vary widely from batch to batch, as will the radioisotopic composition. All radioactive wastes have to packed properly and placed into a geologic repository. The high costs may easily provoke hazardous situations. Economic priorities may lead to relaxation of the regulations to admit higher concentrations of radioactiviy in the debris admitted for clearance for unrestricted use in the public domain [more i26]. The IAEA proposes to dilute radioactive materials, such as scrap originating from dismantling nuclear-related installations, with non-radioactive materials, to be used for 'special purposes'. This is a hazardous proposal for it is inherently uncontrollable.