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Nuclear waste issues

Radioactive waste (sometimes referred to as nuclear waste or 'radwaste') is the solid, liquid or gaseous waste produced by nuclear power stations, nuclear fuel production, reprocessing of spent fuel, weapons manufacture and nuclear plant decommissioning. Limited amounts of radioactive wastes are also generated by industrial, research and medical establishments.

Map showing sources of nuclear waste Click on this image to open a map showing the locations of the sources of nuclear waste. The waste is categorised according to the amount and type of radioactivity it contains. There are three basic types: 1. Low-Level Waste (LLW), 2. Intermediate-Level Waste (ILW) and 3. High-Level Waste (HLW)

Low-Level Waste (LLW) consists mostly of rubbish such as lightly contaminated clothing, paper towels and laboratory glass-ware. Typically these wastes are low in radioactivity and high in bulk. They range from general rubbish (gloves, clothing, packaging, paper towels, over shoes, laboratory glass-ware, etc.) to some very low-level plutonium-contaminated materials (PCM).

Much material, classified as Low-Level Waste, may in fact not be radioactive at all, rather it is the fact that it is potentially radioactive through being in an active/contaminated area that puts it in the LLW category. As a result of the low levels of radioactivity present and the short-lived nature of the contaminants, these wastes are relatively harmless if handled properly. However, any site used for Low-Level Waste disposal will need to be subject to land use restrictions for around 300 years after the site is closed and there is always a risk of environmental problems if water leaching through the waste site finds its way into surface and ground waters. Low Level Waste

Intermediate-Level Waste (ILW) consists of heavily contaminated materials such as used fuel rod casings, used ion exchange resins and parts of decommissioned reactors. This waste can be extremely radioactive but does not require that the heat generated by radioactive decay is taken into account as this is small compared to HLW.

Intermediate Level Waste Due to the large amount of radioactivity present, ILW requires heavy shielding. The radioactive contaminants present in ILW may have very long half-lives and so require isolation for many thousands of years. This picture shows simulated cement-encapsulated ILW from spent fuel reprocessing in a 500-litre drum. There are several ILW sources including: fuel element claddings removed prior to reprocessing (e.g. MAGNOX swarf - see picture above); various sludges and ion exchange resins from fuel storage pond water treatment; concentrates of liquid waste streams; heavily contaminated scrap equipment; plutonium contaminated materials (PCM); and graphite sleeves and steel components from AGR fuel assemblies. In addition, large volumes of ILW from decommissioning operations are expected as more nuclear power plants go off-line and are dismantled. As a result of the broad spectrum of Intermediate Level Waste sources many different forms of conditioning and packaging are required prior to disposal.

High-Level Waste (HLW) consists of spent nuclear fuel and highly radioactive reprocessing liquors.

This waste is the most concentrated and radioactive of the three categories and requires very heavy shielding. As a result of intense radioactive decay processes a large amount of heat is generated which needs to be taken into account in its storage and ultimate disposal. Materials included in the High-Level Waste category include spent fuel and highly radioactive liquids generated during reprocessing operations. The latter is all stored at Sellafield in high-integrity stainless-steel tanks and fitted with cooling coils to remove the heat generated by the decay of fission products, similar to the one shown here. Management and disposal of these wastes is extremely difficult due to the high levels of radioactivity, the extremely long half-lives of some of the radionuclides present and the heat generation as a result of decay processes.

Current practice is to store these wastes, encapsulate them in glass, store them in air-cooled steel containers for 50 years to allow the heat generated to reduce to manageable levels, and dispose of them in a deep mined geological facility.
High Level Waste

Each of these wastes represents a different potential level of hazard and so require different forms of treatment and handling. Some of the wastes are intensely radioactive and heat generating and so require heavy shielding and cooling. Others require no shielding or cooling but will remain hazardous for millions of years. Others contain such low levels of radioactivity that they could be disposed of virtually anywhere without special controls. In practice all types of radioactive waste are regulated to varying degrees depending on their type.

No one really wants radioactive waste. Unfortunately we already have lots of waste to deal with generated by over 50 years of nuclear power generation and weapons manufacture. Finding a way to dispose of this waste may very well encourage its further production, but its presence is a fact that will not disappear whatever happens to the nuclear industry. There will also be a great deal of material produced in the future, as part of the decommissioning of present power stations. We must deal with this material in some manner.

By far the largest waste category in terms of volume presently produced is Low-Level Waste, followed by Intermediate-Level Waste and then High-Level Waste in roughly the following proportions 500:100:1.

By 2030 Britain will have generated approximately 1.4 million cubic metres of LLW, 260 thousand cubic metres of ILW and three thousand cubic metres of HLW. In terms of the total amount of radioactivity, however, HLW is the largest category, followed by ILW and then LLW. All of this waste must ultimately be disposed of somewhere, or stored in perpetuity. Ignoring the problem is not an option; the waste now exists and needs proactive management. It will not go away on its own.

You can find out much more information once you get to the 'Making your Decisions' section, where a comprehensive online information system is provided.


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