MEPhI academics have worked out innovative protective coatings which provide for overhaul-period renewal and enhance exploitation properties and operating capacity of zirconium components of light water reactors under normal operations and in emergencies. As the research has shown, the coating protect fuel-element claddings and other fuel rod arrays from corrosion not only under normal operations but in case of emergency (a maximum design-basis accident with the loss of heat carrier and a beyond design basis accident).
New coatings allow to:
- raise twice or 3 times corrosive resistance of zirconium components under normal operations;
- raise twice or 7 times corrosive resistance of zirconium components in emergencies depending on the coating composition and emergency conditions.
Svetlana Ivanova, Chief Expert at the Institute of Nuclear Industrial technology, the creator of the WWER reactor malfunction imitation device, claims:
- The surface of test samples not protected by the coating has corroded significantly during the test. With the raising of conditioning time at maximum temperature a crumbly white oxidation coating has appeared and samples with the coating have created a dense film under the same conditions at the same time. The corrosive resistance of the samples has enhanced 2-7 times.
The coating worked out by MEPhI scientists have been designed, first of all, for nuclear power, but could be applied in medicine, aviation, machine building as well.
The Chernobyl accident of 1986 happened as a result of zirconium-steam reaction because the temperature of fuel-element cladding rose after the loss of heat carrier and reactivity surge. The Fukushima disaster in 2011 has proved the danger of zirconium-steam reaction. That is why the concept of Accident Tolerant Fuel (ATF) has appeared.
Light water thermal-neutron reactors dominate in nuclear power industry in Russia and other atomic powers. Zirconium components of fuel rod assemblies with elevated level of properties are required in active zones of evolutionary and innovative reactors.
