Terrorist threats to physical security

A rather vacuous story in The Mirror concerning the discovery of vulnerabilities at England's Sellafield nuclear plant is a timely reminder of the extreme risks towards the right hand end of the risk-control spectrum diagram in January's security awareness module.  The news piece, such as it is, reports that after a military "red team" discovered issues at the plant, security is being 'urgently reviewed' to address the risk of a terrorist attack.

"The policing watchdog, in consultation with MI5, will now carry out a review to boost protection of the site, to prevent a “terrorist spectacular”."

The journalist casually mentions:

"An al-Qaeda cell caught plotting to blow up jets in 2006 also had nuclear sites on its hit-list."

I would have thought that 'nuclear sites' (presumably meaning nuclear generators as in this case) were rather low on the terrorist hit list, given the preponderance of much softer yet eqaully high profile critical infrastructure targets capable of causing just as much terror and publicity, plus the rather obvious deterrent effect of strong physical security at 'nuclear sites'.  But what do I know?  I'm no expert at assessing the terrorist threat.

PS  On October 19th 2010, eWeek Europe reported that someone left behind in a local hotel an unencrypted USB stick with information about staffing and health & safety at the plant - not especially sensitive, perhaps, but it is another physical security breach.