The "battery" is an ultra-strong ceramic matrix with a high-energy strontium-90 radionuclide enclosed in it. The material is made by pulsed plasma sintering under high pressure, meets the requirements for solidified radioactive waste and can serve as a reliable radioactive source of autonomous power supply for navigation equipment (beacons, radio beacons, light signs) and weather stations of the Northern Sea Route (NSR).
An article about this was published in Nuclear Engineering and Technology. Stable throughput and navigation accuracy on the Northern Sea Route can be guaranteed by a network of autonomous marine navigation devices operating on radiation current sources (RHS). The most promising RHS elements are based on the high-energy radionuclide strontium-90 (90Sr, RIT-90). The thermal energy of its radioactive decay is converted by thermoelectric generators into electrical energy.
Scientists from the Far Eastern Federal University and the Far Eastern Branch of the Russian Academy of Sciences managed to create a ceramic material with high mechanical strength, microhardness and thermal stability, which is necessary for the safe, without the threat of environmental pollution, placement of cores with strontium-90. A power plant ("isotope battery") made from developed ceramics is one example of the peaceful application of nuclear technology.
RIT-90 is a closed source of ionizing radiation, where strontium borosilicate glass (90SrTiO3) is not an ideal candidate material, since it is subject to vetrification with subsequent mechanical destruction. Despite the protection of the capsule with the core from external influences, the existing RHS-90 handling system does not guarantee physical protection of the RHS element. An accident, unauthorized extraction or terrorist act can lead to the destruction of the RHS core, release 90Sr into the environment, including seawater.
Thus, the radionuclide can be involved in the food chain “bottom microorganisms - algae - fish. The ceramic matrix composition developed by the Far Eastern Federal University and the Far Eastern Branch of the Russian Academy of Sciences reliably protects the core with strontium-90, no matter what happens,”says one of the authors of the work, Ivan Tananaev, director of the School of Natural Sciences (SHEN) of the Far Eastern Federal University.
The scientist recalled that any technogenic radionuclides entering the World Ocean are recorded by the biota. Radiocesium (137Cs) accumulates in phytoplankton (mainly diatoms), macrophytes, coastal brown and red algae, soft tissues of invertebrates and fish. Radio yttrium accumulates in the shell of fish eggs, in algae, crustaceans, in shells of molluscs, cerium-144 (144Ce) - in algae, anemones, in the body of molluscs. Radioactive isotope of iodine (131J) - in algae.
At the same time, if the accumulation coefficient of radionuclides in fish is not high, then for the yolks of waterfowl eggs it exceeds a million units. Strontium-90 is accumulated by ray beams, unicellular plankton, which concentrate it in spicule processes, some green algae, all types of brown algae, in crustacean shells and shells of molluscs.
The Cooperative Threat Reduction Program of the US Congress, which has been in operation since 1991, considers RHSs as a threat to the spread of radioactive materials to create a “dirty bomb”. The IAEA classifies such elements as high risk because one strontium 90 RHS element can be dangerous for more than a thousand years.
Scientists from the Far Eastern Federal University and the Far Eastern Branch of the Russian Academy of Sciences under the leadership of Evgeny Papynov (Institute of Chemistry of the Far Eastern Branch of the Russian Academy of Sciences), using the method of reaction spark plasma sintering (ISP) of mineral-bottom ceramic systems, were able to obtain a stable composition of a ceramic matrix that reliably protects the core with strontium-90. The matrix is capable of "holding" radiation even in the event of an accident and the RHS element gets into the environment, including fresh and sea water.
The IPS approach is based on the consolidation of powder materials due to high-speed heating and compaction. The technique allows you to preserve the microgranular structure of the final material, its high hardness, strength and low rate of radionuclide leaching in environments with different acidity. The technological approach is being developed jointly by specialists from the Far Eastern Federal University and the Institute of Chemistry of the Far Eastern Branch of the Russian Academy of Sciences. According to the researchers, the obtained ceramic material can also be recommended as sources of ionizing radiation based on 90Sr for production at FSUE PA Mayak. The work is carried out within the framework of state assignments of the Ministry of Education and Science of the Russian Federation and scientific projects of the Russian Foundation for Basic Research.