Dounreay Site Restoration Ltd -Historic disposal

Historic disposal

In the early days of the nuclear industry, there was little public scrutiny or interest shown in what happened to radioactive waste, with the focus very firmly on the development of nuclear reactors.

Dumping at sea of some types of intermediate-level waste was allowed while the UK Atomic Energy Authority carried out research into what should happen to other types of waste that were being stored meantime, notably the liquors from reprocessing of spent fuel that were being stored in tanks at sites such as Dounreay and Windscale.

The Radioactive Substances Act 1960 introduced specific government powers, though the UKAEA was already subject to the 1954 Atomic Energy Authority Act.

At Dounreay, the design of the site in the 1950s included tanks for the storage of the highly radioactive waste liquor that would be generated through reprocessing.

In 1956, during the construction phase of Dounreay, discussion about the disposal and storage of other types of solid radioactive waste was recorded in minutes of management meetings. Subsequently, it was agreed that “low activity” solid waste would be disposed to a series of trenches to be excavated at the site while “higher activity” waste would be disposed to the shaft.

Two years later, an authorisation for the disposal of radioactive waste at Dounreay was granted by the then Scottish Development Department of the Scottish Office and included the shaft. The authorisation was required in the name of the Secretary of State for Scotland under the terms of the 1954 Atomic Energy Act. It included authorisation to use the shaft for disposal of higher activity solid waste as well as emissions of lower activity gases and effluent to air and sea.

Intermediate-level waste was deposited in the shaft on more than 11,000 occasions between 1959 and 1977. In the 1960s, as the shaft filled up, it was decided to construct a purpose-built storage facility known as the silo. The first deposits occurred here in 1971, after which the shaft was used only for bulky items. All disposals to the shaft ceased in 1977 after an explosion. A second silo was built in the 1980s but never used. Transfers to the silo ceased in the 1990s, since when this type of waste has been stored in drums above-ground.

The shaft is the only land-based disposal facility ever authorised in the UK for the disposal of intermediate-level waste. This was revoked in the 1990s when it was reclassified by regulators as a storage facility, bringing it into line with the status of the nearby silo.