I have had a cancellation that stranded me for 2 days in Florida, and have had the best part of 12 months haggling with the airline and the CAA over it.
You will be entitled to claim all extra accom and meals providing you keep receipts for all and don't take the michael.
Where you would not be able to claim compensation is if the delay is classed as "an exceptional circumstance" or one which is totally outwith the airlines control, and closing an airport / cancelling flights due to a suspicious package would be classed as this.
There has been a recent court ruling involving JET2 which has just kicked into touch airlines claiming technical faults with aircraft, or staff sickness as an exceptional circumstance. They used to wangle out of payIng compensation using all sorts of tosh as "exceptional".
Basically the courts view any situation within the airlines own control is not exceptional and therefore compensation would be payable at a maximum of 600 euros per person, per EU legislation.
Would be very surprised if a penny was paid as compensation after a bomb scare.