Office for Nuclear Regulation

This website uses non-intrusive cookies to improve your user experience. You can visit our cookie privacy page for more information.



  • Operator/Licensee: Magnox Ltd
  • Parent body organisation: Cavendish Fluor Partnership
  • Type of site: Decommissioning
  • Location: Newburgh, Dorchester, Dorset

Magnox website

Winfrith - Copyright NDA


Winfrith was opened in 1957, to offer additional space for the UK's civil nuclear research programme. Major progress has been made restoring the Winfrith site, since the start of decommissioning in the 1990s.

It became a centre for research and development, including the prototype high gas cooled reactor DRAGON and the SGHWR (Steam Generating Heavy Water Reactor), which provided enough electricity to the National Grid to power a small town. Later the site also diversified into other disciplines, such as safety testing and oil exploration.

Winfrith has had at various times, nine research and development reactors. The last operational reactor at Winfrith closed in 1995, since then the focus for the site has been on decommissioning.

Good progress is being made on the first phase of the Winfrith Site Programme, which focuses on the decommissioning of facilities and the transferring of waste off-site, and achieve the interim end state by 2021.