Today's scenario is an incident involving the transportation of radioactive materials.
"It's extremely unlikely that an event like this could happen for real" said a spokesman for Magnox.
"However we can't allow ourselves to be complacent and need to be prepare for such eventualities".
More top news
Catch up with the latest episode of Coast & Country where Andrew meets the sleddog racing team and Ruth goes weather watching in Snowdonia.
What a week it's been! We started with exceptionally warm temperatures, braved Doris and now it looks like we're in for a wet weekend!
Cardiff manager Neil Warnock has agreed to stay on at the City Stadium, whilst Swansea boss Paul Clement prepares for a return to Chelsea.