Sellafield nuclear leak could pose safety risk

Sellafield, Europe's most hazardous nuclear site, has a worsening leak from a huge silo of radioactive waste that could pose a risk to the public, the Guardian can reveal.

- Anna Isaac, Alex Lawson

Concerns over safety at the crumbling building, as well as cracks in a reservoir of toxic sludge known as B30, have caused diplomatic tensions with countries including the US, Norway and Ireland, which fear Sellafield has failed to get a grip of the problems.

The leak of radioactive liquid from one of the "highest nuclear hazards in the UK" - a decaying building at the vast Cumbrian site known as the Magnox swarf storage silo (MSSS) - is likely to continue until 2050. That could have "potentially significant consequences" if it gathers pace, risking contaminating groundwater, according to an official document. Cracks have also developed in the concrete and asphalt skin covering the huge pond containing decades of nuclear sludge, part of a catalogue of safety problems at the site.

These concerns have emerged in Nuclear Leaks, a year-long Guardian investigation into problems spanning cyber hacking, radioactive contamination and toxic workplace culture at the vast nuclear dump.

Sellafield, a sprawling 2 sq mile site in Cumbria employing 11,000 people, stores and treats nuclear waste from weapons programmes and nuclear power generation, and is the largest such facility in Europe.

A document sent to members of the Sellafield board in November 2022 and seen by the Guardian raised widespread concerns about a degradation of safety at the site, warning of the "cumulative risk" from failings ranging from nuclear safety to asbestos and fire standards.

A scientist on an expert panel advising the UK government on the health impact of radiation told the Guardian the risks posed by the leak and other chemical leaks at Sellafield have been "shoved firmly under the rug".