Zwilag, Nuclear waste repository in Würenlingen, Switzerland

Zwilag is a storage facility for radioactive waste in Würenlingen that contains specialized halls designed to hold different types of radioactive materials safely. The facility stores spent fuel elements and vitrified waste that come from nuclear power plants, research centers, hospitals, and various industries.

The facility began operations in 1990 and received its first shipments of spent fuel and vitrified waste in 2001. It was developed to provide Swiss nuclear power plants and other sources of radioactive materials with a centralized storage solution.

The name combines "Zwischenlager" (interim store) and "Würenlingen". The site belongs to the Swiss nuclear plant operators in proportion to each plant's output, and the operating company was entered in the commercial register in 1990. The 23 Castor containers of vitrified high-level waste and 552 compacted medium-level packages returned from La Hague and Sellafield were at the centre of decades of dispute over reprocessing.

The site is not open to public visits due to strict security and safety requirements for radioactive material storage. Information about the facility can be obtained through official channels and published documentation.

The 23 Castor containers holding vitrified high-level waste, plus 552 individual packages of compacted medium-level waste, arrived from La Hague and Sellafield; repatriation was completed in 2016. Their contents were at the centre of decades of fierce debate over reprocessing between nuclear operators and the anti-nuclear movement.