Scientists at Russia’s Research Institute of Atomic Reactors (NIIAR, part of the scientific division of state nuclear corporation Rosatom) will spend the next several months simulating the behaviour of the molten mass containing components of nuclear fuel at Japan’s Fukushima Daiichi nuclear plant, Ria Novosti reported in October.
The results of this work will support efforts to eliminate the consequences of the Fukushima accident. By the end of February 2019, NIIAR, by order of Rosatom Tekhsnabexport, will undertake research to study of properties of model samples of fuel-containing materials from the Fukushima plant, which suffered three core meltdowns following the March 2011 earthquake and tsunami.
Before work can begin to detect and remove the molten material, it is necessary to draw up a forecast of changes in its properties over the coming several decades.
At the end of January, a consortium of Rosatom enterprises including FSUE RosRAO (Moscow), Khlopin Radium Institute (St Petersburg), NIIAR (Dimitrovgrad, Ulyanovsk Region) and Techsnabexport (leader of the consortium) was selected as the contractor for a project sponsored by the Japanese government to develop technologies for analysing changes in the properties of the corium in the Fukushima-Daiichi units over time.
The first phase of the project was completed this summer. In the second phase, it is planned to produce the corium samples necessary for further research and to form a predictive model for changing its characteristics. This work is expected to be completed by March 2019.
To investigate the properties and develop a predictive model of the changes over time, NIIAR specialists have to complete various tasks.
First of all, it will be necessary to make model Fukushima samples replicating real fragments of corium, to carry out tests according to a programme of so-called “accelerated ageing”, to determine the dynamics of change in the properties of the samples. Next, it will be necessary to confirm the accuracy of the experimental data and its compliance with experimental data obtained from studies of fuel-containing materials from unit 4 of the Chernobyl NPP which exploded in 1986.
Then a predictive model can be developed of change over time (approximately ten years) of the basic properties of the Fukushima samples and recommendations made for its use to assess changes in the parameters of real fuel containing materials at the Fukushima NPP when stored.