but russia s envoy at the un security council insisted it was untrue that his country s forces had shelled the plant, insisting that ukrainian saboteurs were to blame. it was ukrainian emergency crews that dealt with the fire, and the immediate danger now appears to have passed. but nuclear experts say the situation is still precarious. we re not looking at another- chornobyl accident, but the primary concern here is that the electricity sunpiy gets cut off, it stops the pumps from working that cool the reactor. and if that were to happen, - the nuclear fuel inside would melt down, so it s really important that the russian forces - and the ukrainian forces stop firing in the direction - of the nuclear power stations. interruption to the power supply was behind the nuclear disaster at fukushima injapan in 2011. but while that was caused by a natural disaster, this conflict is now drawing close to nuclear power plants that are not designed for war zones. victoria gill, bbc news.