Personal use of work computers can led to serious security breaches in nuclear facilities. Nuclear operators have planned to extend their security beyond the physical measures of barbed wire and high walls, with high profile virus infections and the subsequent leakage of sensitive information onto the Internet. The need to protect company data and keep it away from the public domain is became important, with sensitive information relating to the names and addresses of security personnel being at risk. Most nuclear operators, therefore, recognize the need to have up-to-date anti-virus software. All organizations, especially those with sensitive data to protect, need to put in place a set of guidelines for dealing with security breaches, including the threat from within. It is the responsibility of nuclear employers to ensure the correct IT defenses are in place and that employees are properly educated about the importance of safe computing.