Chernobyl: Current work on site
On 26 April 1986, a serious nuclear accident occurred in Unit 4 of the Ukrainian Chernobyl nuclear power plant. During an experiment, the power of the reactor increased excessively due to a number of operating errors. The fuel overheated, causing several explosions and a fire. This caused about eight tons of radioactive fuel to escape from the reactor core into the buildings and the surrounding area.
New protective shell is sealed
Even 33 years after the accident, its consequences are still visible on the plant site. In 2016, a protective cover was pushed over the destroyed reactor unit and the old Sarcophagus: the New Safe Confinement. Below it, the Sarcophagus is to be dismantled during the next few years, isolated from the environment. First, unstable parts of the Sarcophagus are to be dismantled. The remaining Sarcophagus and the destroyed reactor can then be dismantled and the materials containing nuclear fuel salvaged.
Functional and acceptance tests for the ventilation system are still in progress. Recently, there have been repeated delays, as the New Safe Confinement has not yet been completely sealed.
The interim fuel element storage facility (ISF-2) for the fuel elements used at the site is currently being tested and is scheduled to be commissioned in 2020. Up to 21,000 irradiated fuel elements are to be put in dry storage here. The low- and intermediate-level waste is currently stored in the Buryakovka repository, 13 km away from the nuclear power plant.
GRS experts collect data on forest fires
GRS has been dealing with the Chernobyl reactor accident and its consequences since 1986. This includes both the scientific analysis of the accident and the support of the local authorities. Since 2006, GRS has been developing the "Shelter Safety Status Database" (SSSD) together with Ukrainian scientists. The database collects data on the radiological situation on site, which is gathered in cooperation with Ukrainian experts.
The database is currently being supplemented with information specifically on forest fires. In areas inside and outside the 30-kilometer exclusion zone, forest fires are more frequent during periods of severe drought. The fires can cause radioactive particles to swirl up and enter the atmosphere. In the database, the experts now combine information on the forest fires with the measured air values in order to better investigate possible correlations between the fires and polluted air.
Projects for the handling of nuclear-fuel-containing materials at Chernobyl
In another project, GRS is supporting the Technical Safety Organisation (TSO) SSTC/NRS and the Ukrainian supervisory authority SNRIU in finding ways of handling the nuclear-fuel-containing materials within the Sarcophagus in the future. The main focus is on regulatory issues such as how unsealed nuclear fuels can be optimally monitored up to their salvage and disposal. The nuclear fuel is present in different forms, among others as so-called lava (see figure), as dust, or dissolved in water.
Among other things, the scientists analyse which factors have a significant influence on the condition of the nuclear fuel.
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