Comment: Really bad if the battery catches fire (Score 4, Informative) 213
There is a 250 volt battery with a huge amount of potential energy. You have basically a medium size bedroom full of batteries that are 6 feet tall.
The battery can keep the lights running for about 1.5 hours while also supplying power to move it through the water and power the reactor plant to do a restart.
We calculated one time that if all the energy in the battery was released at once (not possible, we knew that), it would blow the sub 1.5 miles into the air.