(547.5263) WISE Amsterdam - The Chernobyl reactors 1 and 2 were closed years ago (1996 and 1991) due to numerous defects and incidents. Reactor 3 however continued operation until 15 December 2000. That closure was a precondition for the Ukraine to get European Bank for Reconstruction and Development (EBRD) funds for the completion of the Khmelnitsky 2 and Rovno 4 reactors (K2R4). The EBRD also administers a fund that is used for the improvement of the Chernobyl 4 sarcophagus.
The present sarcophagus was hastily built in the months after the 1986 disaster around the wreckage of reactor 4. But it was not meant as a permanent bunker for the remaining nuclear waste. Although an enormous amount of radioactivity was spread during the disaster itself, most of the radioactivity remained in the debris of the reactor. More than 200 tons of uranium and close to a ton of other radioactive products, of which 80 percent is plutonium, remain within the deteriorating shelter. The remains also contain some 2,000 tons of combustible materials. In the basement, rainwater and finely divided fuel dust have formed a liquid that is regarded as high level waste.
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FIRE AT RIVNE |
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REMEMBRANCE AND DEMONSTRATION On Chernobyl Day, a big demonstration took place in the capital of Finland, Helsinki. Some 3,000
demonstrators walked to the parliament in a protest against plans to construct a fifth nuclear
power reactor in Finland. The demonstrators were welcomed in a speech by environment minister Hassi
of the Green party, which also objects to the plans. Other parliament fractions supported the
demonstrators as well. It is still unclear when the Finnish parliament will decide about the
proposal but it will take at least a year before a decision. |
The shelter was built within a few months after the disaster under extremely dangerous conditions due to the high radiation. Some 300,000 people were involved in its construction. In the days after the explosion, the reactor was covered with thousands of tons of material to slow down the nuclear reaction and extinguish the fire. Later, large steel fabrications were laid on the reactor remains, concrete walls were constructed around the reactor which again was covered by steel beams and concrete slabs. The purpose was to provide weather protection and prevent the spread of radioactivity. The extreme urgency and the high radiation however resulted in a poor construction.
Part of the shelter was built on top of the unstable foundations of the reactor building. Especially the stability of the west wall was of great concern. If it collapsed, the whole roof would come down. There are a large number of holes in the structure with a total surface of about a thousand square meters. With strong winds, radioactive particles are able to escape from the sarcophagus. Penetrating rainwater contributed to the risk of chain reactions. There has been a fear that this water eventually would reach the groundwater. However until now it has not reached the groundwater and some unknown kind of barrier obviously has prevented this.
Since its construction, the shelter structure has deteriorated. There has been serious weather penetration and the roof and other structures have been in real danger of collapsing. Warnings about the risk of collapsing and leaks repeated over the years. Valentine Kupny, formerly Shelter facility director, said this month to the German weekly Focus: "If we could see the radioactivity, there would be a cloud of smoke above the sarcophagus". Kupny was sacked from the Chernobyl station in March, officially due to "violation of duty", but Focus said his dismissal came shortly after he had been interviewed. According to Kupny, nuclear chain reactions inside the debris had been observed for the last time in September 1996 (ten years after the disaster!) but could still take place. Also in 1990 and in 1995, radiation equipment detected an increase in neutron flow coming out the debris.
Over the time, several proposals were made for the improvement or replacement of the existing sarcophagus. The proposals were mostly made by consortiums of international nuclear companies. The lack of financial resources and commitments was reason that it took so long to start the reconstruction project.
The currently running Shelter Implementation Plan (SIP) was developed in early 1997. The project duration was estimated at eight to nine years. The plan is to make a steel construction over the existing shelter. But on top of the existing sarcophagus the radiation is still too high and workers would only be able to work for some minutes before they receive their permissible radiation dose. The steel arches of the new shelter are to be constructed next to the building, then put on a railway and pulled over the existing shelter. The new shelter is supposed to isolate the reactor for 50 years according to the EBRD. Work on the construction has not begun yet and will take at least five years to complete.
The fear of water leaking into the groundwater is not taken into consideration in the Shelter Implementation Plan. The proposal to construct a slab of concrete beneath the reactor is absent in the present plan. Ukraine authorities had proposed to dismantle and store the remaining debris inside the new shelter over the years. The Shelter Implementation Plan however does not take this option into account but leaves it open for the future.
The main companies involved are Energoatom (Ukraine), Bechtel (USA), EdF (France) and Battelle (USA). These four make up the Project Management Unit. Several other companies are involved in subprojects.
The total costs of the Shelter Implementation Plan are estimated by the EBRD at US$768 million. Others however think the costs will be much higher. Vladimir Asmolov of the Russian Kurchatov Nuclear Institute and involved in the original construction of the shelter thinks that the costs could reach as much as US$2.5 billion.
The Chernobyl Shelter Fund (CSF) was set up in December 1997 with the purpose of funding the Shelter Implementation Plan (SIP). The EBRD administers the Chernobyl Shelter Fund. As of July 2000, 37 countries had contributed US$715 million to the fund, which is 93% of the overall project cost estimate. Most of the money comes from the European Union and the G-7 countries.
The first phase of the Shelter Implementation Plan consisted of an expedited review of the collapse risk and the most critical repairs were conducted. Further, studies were conducted and designs been made for a structural stabilization of the shelter, to be conducted in the second phase.
Two projects of the first phase which had to start without delay were repairs of the beams supporting the roof of the shelter (1999) and stabilization of the ventilation stack (1998), whose possible collapse was also threatening the then still operating reactor 3. The second phase will consist of the actual strengthening of the present sarcophagus and the construction of the new covering shelter.
Sources:
- Chernobyl Shelter Fund newsletter, EBRD, December 1998
- Shelter Implementation Plan
- Chernobyl Shelter Fund, EBRD, February 2000
- AFP, 13 and 23 April 2001
- KPnews, 13 April 2001
- Frankfurter Allgemeine Zeitung (FRG), 25 April 2001
Contact: WISE Amsterdam
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