There are three categories of radioactive nuclear waste; High level waste (HLW), Intermediate level Waste (ILW) and Low level waste (LLW).

HLW consists mainly of irradiated fuel from the cores of nuclear reactors (although the nuclear industry do not consider this to be a waste), and the high level liquid waste produced during reprocessing. The removal of plutonium by reprocessing results in a huge volume of this liquid radioactive waste. Some of this deadly reprocessing waste, stored in large tanks, is mixed with a hot glass material and solidified, with the resulting glass logs also being classified as HLW. While the glassification process may make it easier to transport and store the nuclear waste, it does in any way diminish the terrible danger posed to the public and the environment for millenia to come. HLW is typically a thousand times more radioactive than ILW.

ILW consists mainly of metal fuel 'cans' which originally contained the uranium fuel for nuclear power stations; reactor metalwork and chemical residues. It has to be shielded to protect workers and the public for exposure during transport and disposal. It is usually stored at the site of production. ILW is typically a thousand times more radioactive that LLW.

LLW can be defined as waste which does not require shielding during normal handling and transportation. LLW consists mainly of items such as protective clothing and laboratory equipment which may have come into contact with radioactive material.

DISPOSAL OF RADIOACTIVE WASTES

The highly radioactive nuclear fuel is removed from the reactor and at most sites this "spent" fuel is being stored temporarily in water-filled cooling pools. As the cooling pools of many reactors are rapidly being filled, many reactors may soon have to shut down due to a lack of storage space for the deadly waste. According to estimates by the International Atomic Energy Agency (IAEA), the global amount of spent fuel was 125,000 tonnes in 1992, and this will rise to 200,000 tonnes by the year 2000, and to 450,000 by the middle of the next century. Yet, although a variety of disposal methods have been under discussion for decades -- including disposal in space -- there is still no solution for what to do with nuclear waste.

Most of the current proposed 'solutions' for dealing with nuclear waste involve burying it under ground in a special store with strong enough protection to stop its radioactivity escaping. The nuclear industry purports that after some form of processing, burial in the ground or the seabed, will be sufficiently safe. This philosophy was born largely under the pressures of having to convince a worried public that the nuclear industry knows how to dispose of its wastes. However, this is a false assurance.

To pretend, as the nuclear industry often does, that a few experiments, test bores or geological surveys is all that is needed to deal with radioactive waste is simply disingenuous or scientifically illiterate or possibly both. Adequate proof will take tens of thousands of years.

The two main dangers inherent in the burial of nuclear waste are air and water contamination.

Air Contamination

Explosive or slow releases of gases from an underground disposal site is theoretically possible. There is unfortunately no reliable way of estimating this danger - there are too many uncertainties concerning actual methods of burial and of possible chemical interactions within a real environment.

Water Contamination

This is generally taken as the most likely mechanism of pollution in connection with waste disposal in rock. Underground waters may come in contact with radioactive elements that have leached out from the waste and contaminate the drinking water of local and distant communities.

In addition to underground burial, various on-site storage schemes are being investigated. Of primary interest is the storage of the spent fuel in large steel or concrete containers. While on-site storage of spent fuel keeps the material at the point of its creation and reduces transportation risks, hundreds of communities around the world are threatened with de facto high level dumps on their doorsteps. Plans also exist for consolidating containerised spent fuel at a few above-ground regional facilities, resulting in a huge number of road transports in containers not designed to withstand credible accidents.

The best solution for the future is that no more nuclear waste should be produced anywhere in the world.

DISMANTLING NUCLEAR POWER STATIONS

Large quantities of nuclear waste are also produced when a nuclear reactor is shutdown. This is because many of its component parts, including the fuel, have become radioactive. They cannot simply be thrown away. The process of dealing with the power station at this point is called "decommissioning". Apart from removing the used fuel, however, there is not a clear agreement about what should happen next. No full size reactors has yet been fully dismantled anywhere in the world. Although some countries are planning to remove the entire structure, including the radioactive parts, leaving a flat empty space, others have suggested leaving the building where it stands, covering it in concrete or possibly burying it under a mound of earth.

The cost of decommissioning nuclear power reactors is highly speculative. Cost estimates have been derived from generic studies, from scaling up the costs of decommissioning smaller research facilities. The detail and sophistication employed in developing these estimates varies greatly and their lack of standardisation makes comparisons difficult. Moreover, limited decommissioning experience - none with large reactors - makes it impossible to know if the estimates are on target, but it has been suggested that decommissioning costs could be up to 100% of the initial cost of construction.