It followed a routine inspection at the Atomic Weapons Establishment (AWE) in Aldermaston, Berkshire, by the Office for Nuclear Regulation (ONR).

BBC: AWE building

Scott Coombe, product manager for RSEP, a collaboration between ONR's Expeditionary Maneuver Warfare and Combating Terrorism and Sea Warfare and Weapons departments.

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The Office for Nuclear Regulation (ONR) awarded the licence to NNB Generation Company (NNB GenCo), which is handling the bid to build new reactors.

BBC: Hinkley Point nuclear station: Licence granted for site

The ONR said the key did not contain "significantly sensitive" data.

BBC: USB stick with nuclear plant data lost by ONR official

The unencrypted USB pen drive, containing a 'stress test' safety assessment of the Hartlepool plant, was lost by an employee of the Office for Nuclear Regulation (ONR).

BBC: USB stick with nuclear plant data lost by ONR official

The ONR, which is an agency of the Health and Safety Executive, said the use of unencrypted devices for transporting documents with a security classification was not allowed.

BBC: USB stick with nuclear plant data lost by ONR official

The new deal signed off by the ONR and Horizon-Hitachi ensures that the nuclear developers will foot the entire bill for putting the new ABWR designs under the microscope.

BBC: Wylfa: Anglesey nuclear reactor plans move forward

An ONR spokesman said at the start of the stress test programme, there had been a commitment to publishing the reports, so most of the findings were now in the public domain.

BBC: USB stick with nuclear plant data lost by ONR official

"The RSEP program is a key initiative in the Marine Corps' expeditionary power systems portfolio for advanced power sources that embrace renewable energy systems as a means to reduce fossil fuel requirements, " said Mike Gallagher, program manager for expeditionary power systems at Marine Corps Systems Command, which will work with ONR to transition the technology to the field.

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