A MEMORY stick containing a safety assessment of a North-East nuclear power plant has been lost.

The unencrypted data was misplaced by an employee of the Office for Nuclear Regulation (ONR), an agency of the Health and Safety Executive (HSE), while attending a conference in India.

The lost stick contained a safety assessment of Hartlepool’s nuclear plant, which was undertaken in the wake of the Japanese radiation scare at the Fukushima nuclear plant.

People have been reassured that no significant data was lost and the majority of it has since been put into the public domain.

An ONR spokesman said: “An ONR member of staff lost an unencrypted USB pen drive containing the licensee’s “stress test” of a UK nuclear power station, which is a safety assessment of the station.

“It did not contain any significantly sensitive information.

“At the start of the European Commission stress test programme, the licensees of all UK nuclear power stations committed to publishing their “stress test” reports, so most of the findings in this report are now in the public domain.

“The use of unencrypted USB pen drives is not permitted by ONR for transporting documents with a security classification.

“An internal investigation has been undertaken by ONR.”

EU governments agreed last March that, in the wake of the Japanese earthquake and resulting tsunami that overwhelmed the Fukushima nuclear plant, all 143 of Europe’s plants should undergo stress testing to common standards.

The site owner, EDF, which is considering a new nuclear power station that would create 3,000 temporary posts during the five-year building programme, has reassured people that there is no risk connected to the loss.

Paul Newman, station director at EDF Energy’s Hartlepool Power Station, confirmed the memory stick did not contain highly sensitive information.

He said: “The reports on the website have slight differences to the full technical versions in that some of the technical language has been simplified to avoid misinterpretation of the information, and more detailed data like site layouts has been removed, although we reiterate that the document on the memory stick does not contain any significantly sensitive information.”