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i07

How clean is nuclear power?

Nuclear power is pointedly advertised as a clean energy source. Examination of the complete series of industrial processes needed to make nuclear power possible [more i12, i13] reveals a picture of nuclear power completely different from the usual connotation of 'clean'. The nuclear process chain consumes massive amounts of chemicals. From the basic laws of nature follows that losses and leaks are unavoidable, so a certain fraction of the used chemicals are inevitably discharged into the environment. Planned and unplanned dispersal of unwanted substances are exacerbated by economic pressure and imperfect human behaviour.

Greenhouse gases

The nuclear reactor is the only part of the nuclear system that does not emit CO2, all other parts do. Under the current conditions the specific CO2 emission of nuclear power is roughly 80-130 gram CO2/kWh. This figure will rise during the next decades, due to the depletion of high-quality uranium resources and dependency on ever decreasing ore quality [more i05]. Emissions of greenhouse gases other than carbon dioxide into the environment by the nuclear energy system are kept secret. However, in the front end processes of the nuclear chain massive amounts of fluorine (at least 130 tonnes per gigawatt.year (GWe.a)) and chlorine (at least 102 tonnes GWe.a) are being consumed, either in elemental form or as compounds with other elements. In 2010 the world nuclear electricity generation was 316 GWe.a per year, so the global consumption of fluorine and chlorine in the nuclear system in 2010 were respectively 41000 and 32000 tonnes per year at least. Many gaseous chloro-fluoro-compounds are potent greenhouse gases. Emissions seem not only possible, but even likely, for no chemical plant is leak-proof.

Chemicals

In the industrial processes of the nuclear chain substantial amounts of chemicals are cunsumed [more i13]. Fluorine and chlorine are already discussed above. Per gigawatt.year (GWe.a) one nuclear power plant consumes in its process chain some 22000 tonnes chemicals, most of it for the extraction of uranium from the earthÕs crust (mining and milling) and for the maintenance of the power plant itself. More than 17000 tonnes/GWe.a of these chemicals are routinely discharged into the environment, corresponding with 5.4 million tonnes per year by the global nuclear power fleet. Chemicals needed for mine area rehabiliation are not included in these figures. A small part of the discharged chemicals are environmentally harmless from a chemical viepoint, such as lime, most other are far from harmless. Besides the discharged chemicals are contaminated by radioactive substances and mobilized toxic elements.

Radioactive discharges

Releases of radioactive substances into the human environment occur in all phases of the nuclear process chain. Particularly the processes of the back end are potential sources of substantial emissions of radioactivity, for these involve a billionfold of the amounts of radioactivity compared to the front end. The nuclear reactor and the back end processes discharge considerable amounts of radioactivity into the environment on routine base [more i17]. These emissions are going on day after day, year after year. Radioactive contamination is cumulative and irreversible.

Usually the nuclear industry is concealing the radioactive emissions, or playing them down if disclosed nevertheless. Even authorized emissions of radioactive materials which are officially classified as harmless are proved to be harmful for people living in the neighbourhood of nuclear power stations. Serious are the massive radioactive contaminations as result of large accidents, such as Chernobyl and Fukushima [more i21, i43]. Accidents are unavoidable, as long as all human-generated radioactivity is not permanently isolated from the human environment. The chances of large nuclear accidents are increasing with time, due to several factors, such as:

• increasing amounts of radioactive materials in an increasing number of temporary storage facilities

• progressive deterioration of the materials and structures of the temporary storage facilities

• increasing economic pressure [more i26].

Ecosystem disturbances

As a result of nuclear power-related activities permanent disturbances of large areaÕs occur. Some disturbances are visible, for instance the mining areas of uranium and other consumables, other are not directly visible but become evident in the long term in an insidious way. Radioactive contamination is irreversible and accumulative. The adverse effects in humans have often long incubation times [more i22].

Radioactive dust is spread by the wind over vast areas (hundreds of thousands square kilometers) around uranium mines [more i18]. In addition to radiological hazards, this dust contains biochemicall toxic substances and elements. Uranium and its decay daughters are from harmless even at very low concentrations. The groundwater tables in regions with uranium mines are irreversibly intoxicated with numerous kinds of chemically and radiologically hazardous substances.

Large areas are affected by the routine releases of radioactive materials, especially by planned and unplanned releases from reprocessing plants [more i17,i19]. Due to accumulation in the food chain high concentrations of radionuclides are possible locally. Obviously severe nuclear accidents cause serious and permanent disturbances of vast areas by contamination by all kinds of radionuclides, rendering major parts of these areas (tens to hundreds of thousands square kilometers) inhabitable [more i21, i24]. A number of the radionuclides are difficult to detect by common radiation detectors.

Depletion of valuable materials

In the nuclear process chain a number of materials are consumed in a once-only mode. An example is zirconium, used for fabrication of the cladding of nuclear fuel elements. Due to its high radioactivity this zirconium is not recyclable. The zirconium consumption is nearly 50 tonnes/GWe.a, corresponding with some 16000 tonnes per year globally. Another example is bentonite, a clay mineral with special properties, which is needed to isolate radioactive waste from groundwater ingression for very long times. If all radioactive wastes from the nuclear chain would be conditioned properly, the consumption would be around 84000 tonnes/GWe.a, or more than 26 million tonnes per year globally [more i13]. How large are the bentonite resources? How large are the areas disturbed by the mining of these amounts?

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