The second-stage engine cut out three minutes too soon, apparently because of a leak caused by a tool left inside it after a test firing two years ago.

ECONOMIST: Sayonara, spaceflight?

The exercise, with a command centre in Poundbury, Dorchester, will test their response to the scenario of a radioactive leak from a submarine with a damaged nuclear reactor core.

BBC: Nuclear submarine accident exercise in Portland

Last year, Mr. Snow said, contractors found a leak in a building that was slated for demolition, spurring them to test the nearby soil.

WSJ: Toxic Radioactive Find Adds to Hanford Cleanup Woes