Post date: Apr 25, 2011 3:49:49 PM
Chernobyl rescuer who has written a book about the disaster describes rescue operation, reveals details previously unknown to the public.
MOSCOW, RUSSIA (APRIL 23, 2011) REUTERS - A quarter of a century since the meltdown at Ukraine's Chernobyl power plant, the international community is still trying to secure funds to make the site of the world's worst nuclear accident safe.
After Chernobyl's No. 4 reactor exploded on April 26, 1986, a "sarcophagus" was built over a period of six months as a temporary measure to stop radiation from spreading, with workers often putting their life at risk to complete it.Elena Kozlova was head of chemical laboratory at a Moscow scientific institute which was part of powerful Soviet Ministry of Medium Machine Building, responsible for nuclear reactors around the country. The most urgent task set before the ministry was to build a shelter, later called "sarcophagus", to isolate the reactor.
When Chernobyl's No. 4 reactor exploded highly radioactive fragments landed all around the area. Before works on the shelter could begin, highly radioactive debris had to be removed from the area around the reactor and from its roof. The radiation level around the reactor was too high for anyone to come close.
Kozlova's institute was asked do develop the safest possible way of removing highly radioactive debris from the roof of the reactor where it was too dangerous for the rescue teams to work.
Kozlova's team came up with a safe solution.
A giant 'collector' in the shape of a carpet would be saturated with a special glue and placed by a helicopter on the parts of the plant roof with the most contaminated fragments.
"The airfield in Chernobyl was 17 kilometres from the power plant. There, on the airfield, we set up a container with glue for the saturation of (radiation) collectors. There was a special lock for a helicopter to pick up the collector. The helicopter would lift it and carry to the Chernobyl zone. Ahead of the operation we would determine where the (radiation) collector would be placed, "said Elena Kozlova.
"We would locate the biggest highly radioactive fragments and the helicopter would drop the collector on top of these fragments and debris. The collector surface space was a square of 4X4 metres, 16 square meters in total. To saturate that space we needed 300 kilos of glue. The helicopter would drop it on top of a fragment. After we were certain that the glue had hardened after a few days the helicopter would take off again and with the help of a an anchor would hook up the collector and lift it with debris," she added.
But before the collector could be placed the right spot, with the highest level of radioactivity, had to be identified. It was impossible to do remotely from a helicopter so the engineers designed a capsule capable of carrying one researcher at a time on top of a dangerously contaminated roof to check the levels and mark the spot.
"In order to be able to locate the most contaminated fragments and collect them, a special capsule was designed and delivered to Chernobyl. We called it the 'bathyscaph' (submersible cabin). It was a capsule covered with lead which weighed 28 tonnes. It was lifted by a crane to the place which needed to be photographed and explored. I went in the capsule only once," recalled Kozlova.
This part of the operation was in fact the most dangerous one. The capsule carried by the crane would be hanging above the roof which had not been built to withstand heavy objects. Had the crane operator miscalculated the descent of the capsule by a centimetre there was a danger of it falling into the nuclear abyss.
"The crane would lower the 28 tonne capsule. The roof could only hold a relatively light load. We couldn't even place any equipment there. It was a light roof and the capsule could not be put on it under any condition. But when the crane moved it towards the roof it had to hold it above the roof because if it lowered it to touch the roof there would inevitably be a jump and the loop could come off the hook. And of course the roof would not be able to sustain the weight of the capsule and the capsule would drop down. That moment was the most dangerous for all of us who were lifted in that capsule. We even called those people (in the capsule) the cosmonauts ," said Elena Kozlova.
Kozlova has written several books about the rescue operation and has been honoured with numerous state awards for her contribution to securing the disaster area at Chernobyl.
A makeshift shelter, the 'sarcophagus', over the damaged reactor erected hastily in the aftermath of the disaster is to be reinforced with a new shell as high as the Statue of Liberty and almost three times as heavy as the Eiffel Tower.
A new storage facility for the decommissioning of spent fuels is also planned.
The project will cost close to one billion euros and will be built to last for at least 100 years. The structure will be based on a huge lattice of tubular steel bars built on two concrete beams. It will be assembled on site, 250 metres away from the still highly radioactive No.4 reactor and then slid into place, covering the reactor building.