Office for Nuclear Regulation



  • Operator/Licensee: Magnox Ltd, Inutec Ltd
  • Owner: Nuclear Decommissioning Authority
  • Type of site: Decommissioning
  • Location: 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. Preparatory works for safe dismantling of the SGHWR and DRAGON reactor core are advanced with dismantling expected to start in the next 2-3 years. Preparations are starting for the removal of the Winfrith sea discharge pipeline, with learning being taken from the successful completion of removal of the Harwell offsite discharge pipe in 2020.