Under the 4th reactor, in the so called bubbler pool (a reservoir for the emergency cooling pumps), and in the basement underneath it, a large amount of water had accumulated; according to some sources, it was a matter of approximately 20 000 metric tons of water, but as I cannot verify these sources I ask you not to pay too much attention to this number.
The water had assembled in the concrete room under the 4th reactor as a result of assumedly ruptured water pipes and definitely the first attempts to put out the fire in the reactor core, and the active fuel had already reached partly through the concrete floor when it came to attention that if it would reach the water, there would be a great risk of a thermal explosion that would make all of the nothern Ukraine and most of Belarus uninhabitable for a long time to come. Naturally then, the water would have to be removed.
A common mistake is obviously to assume that firefighters performed this drainage but perhaps that common mistake is understandable, as the facts and information concerning this matter are quite vague. In any case, the water had to be drained manually, by opening the floodgates at the bottom of the room. This meant that divers had to descend into the now highly radioactive water. The official story tells that three men volunteered, but what's for certain is that their names were Aleksey Ananenko, Valery Bespalov and Boris Baranov.
Ananenko was an engineer who had helped in the design of the floodgates, why he had to lead the way. Bespalov was a colleague, also employed at the ChNPP and Baranov, who never descended, was a soldier of the Red Army, whose function was to light their underwater way. However, Baranov's lamp failed and thus Ananenko and Bespalov were forced to find their way by feeling and following a main pipe.
|To the lost workers of Chernobyl|
Eventually they found the floodgates and managed to release the water and afterwards, the basement underneath could be drained by using fire brigade pumps.
Having been exposed to lethal doses of radiation 15 Sv (15 000 Roentgen), the three men involved in the bubbler pool operation, all suffered of acute radiation syndrome. Aleksey Ananenko and Valery Bespalov died shortly after. There are no known reports concerning Boris Baranov - we can only assumed that also he's no longer alive.
The heroes of Chernobyl are many and the majority of them will never get a mentioning, but nonetheless they all helped to save the world.