Radioactive waste

One property of radioactivity is that the radiation decreases with time. Nature takes care of this itself. The more time has lapsed, the weaker the radiation will be. This is due to the radioactive decay of the unstable atoms in a radioactive substance. Unstable atoms emit radiation until they become stable. At that point, they have decayed and can no longer emit radiation. The time this decay takes is expressed in half-life. This is the time required to keep losing half of the radioactivity. After two half-lives, radioactivity will have been reduced to half of half. In other words, a quarter of the initial value. Each radioactive material has its own fixed half-life. For one substance this may be just seconds, while others may need thousands of years. Some radioactive substances are therefore harmless as soon as they come into being. Other radioactive material needs to be stored for thousands of years before it stops emitting radiation.

Radioactive waste eventually turns into a substance that is no longer dangerous. How long this takes depends on the radioactive material. This varies from a few to thousands of years. Therefore, it is important to store radioactive waste safely until it no longer emits radiation.

Radiation is the ‘problem’ of radioactive waste and at the same time the solution. Radiation is potentially dangerous for people and the environment, which is why we have to handle radioactive waste carefully. Radiation also reduces the radioactivity of the substance. At a certain point, the waste no longer emits radiation and is no longer dangerous. That is why it is important that we process and store radioactive waste in a safe manner until the waste no longer emits any radiation. This is the responsibility of COVRA.

In the Netherlands, we produce millions of cubic metres of waste per year. Only a very small proportion thereof is radioactive waste. This waste is the result of working with radioactive materials. Radioactive materials are used in the production of electricity, in medical diagnoses and treatment of illnesses and for checking the welds of steel constructions of wind turbines, among other things. Even for the restoration of paintings, nuclear reactors are used and also the drying of the ink on, for example, juice boxes takes place with the aid of radioactive radiation. There are some 1000 companies in the Netherlands that work with radioactive materials. The resulting waste includes laboratory consumables such as gloves, clothing, syringes and glassware, smoke detectors, reactor replacement parts such as pipes, pumps and filters and spent nuclear fuel from reactors. Radioactive waste can be solid or liquid. It can be flammable or non-flammable, compressible or incompressible. Each type of waste deserves a specific treatment to allow it to be stored as safely as possible.

Approximately 110 m³ of high-level radioactive waste is stored at COVRA. In terms of volume, this represents the contents of 1.5 large sea containers. Each year, approximately 4.5 m³ of high-level radioactive waste is added. This is the same as the contents of three roll containers. Approximately 34,000 m³ of low and intermediate-level radioactive waste is stored. This amount could fill about 1/20 part of a large container ship. This amount annually increases by approximately 1,100 m³ of low and intermediate-level radioactive waste. This represents the contents of 16 sea containers.

The above data are the figures as they were by late 2018.

There are three types of radioactive waste: high-level radioactive waste (HLW), low and intermediate-level radioactive waste (LILW) and ‘Naturally Occurring Radioactive Material’ (NORM).

High-level radioactive waste

High-level radioactive waste produces high levels of radiation. Processing this waste requires special measures. These include remote-controlled equipment, 1.7 metre thick reinforced concrete walls and one metre thick doors. High-level radioactive waste is produced by nuclear reactors, such as research reactors, the production of medical isotopes and the nuclear power plant in Borssele. The spent nuclear fuel from the nuclear power plant is first recycled in France. The remaining waste is sent back to COVRA.

Low-level and intermediate-level radioactive waste

Low and intermediate-level radioactive waste is less dangerous than high-level radioactive waste. This waste can be stacked using an ordinary forklift truck. This waste comprises, for instance, gloves, laboratory coats or jars that have been used during activities with radioactive waste. A spilled drop of radioactive liquid landing on something else already means radioactive waste is created. Even a refrigerator containing radioactive liquid can thus become radioactive waste.

NORM
A special category of low and intermediate-level radioactive waste is NORM (Naturally Occurring Radioactive Material) waste. NORM waste is generated when natural radioactive substances present in industrial ores (such as phosphate ores) are concentrated as a result of an industrial process.

Approximately a thousand companies in the Netherlands are authorised to work with radioactive substances. Radioactive radiation is used, for example, in the production of electricity, in medical diagnoses and treatment of illnesses and for checking the welds of steel constructions of wind turbines, among other things. Even for the restoration of paintings, nuclear reactors are used and also the drying of the ink on, for example, juice boxes takes place with the aid of radioactive radiation. The waste includes laboratory consumables such as gloves, clothing, syringes and glassware, smoke detectors, reactor replacement parts such as pipes, pumps and filters and spent nuclear fuel from reactors.