Nuclear waste is safe and sound with polymer storage

The UK has a unique problem with nuclear waste. As a pioneer in the nuclear sector in terms of the development of weaponry and of nuclear power a variety of equipment designs were used in the early days, along with unusual materials and much experimentation.

Even though the development work took place mostly in the 1950s and the 1960s, the legacy remains: a large stockpile of waste often described using the mild-sounding adjective ’exotic’. Very different from that produced by commercial thermal reactors, it presents problems for the decommissioning process. All of these wastes have to be encased in materials that will contain their radioactivity when they are placed within the proposed deep geological repository; and the encapsulation must remain intact until the activity has declined to safe levels. In some cases, this could take thousands of years.

Engineering consultancy Babcock is taking the lead on waste encapsulation, and technical and assurances service group section manager Steven Black told The Engineer that, for many wastes, there is a tested and approved treatment method. Spent fuel, for example, is vitrified before being sealed in a copper canister. Most other wastes are entombed in a cement box filled with a grout, made from Portland cement mixed with powdered fly ash from furnaces or blast furnace slag. This mixture is chemically stable, has established physical properties, is proven to be long lasting and is cheap. It’s also compatible with most types of waste. Most, but not all.