EXPERIMENTAL STUDY OF THE DEGRADATION OF MODEL FUEL ASSEMBLIES IN ACCIDENTS WITH UNCONTROLLED FLOW OF SODIUM LOSS

Authors & Affiliations

Zagorulko Yu.I., Ganichev N.S., Zhmurin V.G., Kasheev M.V.
A.I. Leypunsky Institute for Physics and Power Engineering, Obninsk, Russia

Zagorulko Yu.I. - Leading Researcher, Cand. Sci. (Tech.), A.I. Leypunsky Institute for Physics and Power Engineering. Contacts: 1, sq. Bondarenko, Obninsk, Kaluga reg., Russia, 249033, Tel.: (484)399-80-84, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Ganichev N.S. – Research Engineer I category, A.I. Leypunsky Institute for Physics and Power Engineering.
Zhmurin V.G. – Lead Engineer, A.I. Leypunsky Institute for Physics and Power Engineering.
Kasheev M.V. – Senior Researcher, Cand. Sci. (Tech.), A.I. Leypunsky Institute for Physics and Power Engineering.

Abstract

In the article there are presented results of investigation on the final state of 19-rods subassembly mock-up after simulation experiment in conditions of unprotected lose of sodium flow rate. Experiment was carried out on the installation “Pluton” at initial sodium temperature of 823 K. Corium was simulated by a melt of thermite reaction products (Al₂O₃+Fe, T ~ 3100 K). Along with overall picture of fuel pins simulators degradation there were investigated final distribution of materials on the subassembly height, blockage phenomena and materials release out of subassembly volume. Experimental data analysis has shown that principal mechanisms of fuel pins simulators claddings degradation could be referred to temperature stresses and material melting. Dynamic effects, caused by sodium/corium thermal interaction,are responsible for materials final redistribution inside of the subassembly and their release out of subassembly volume (80-85 % as referred to thermite mixture initial mass). There was detected almost total blockage of the subassembly bottom part. Composition of the plug materials corresponded to that of fuel pins simulators claddings.

Keywords
melting, degradation, fuel assembly, accident, nuclear reactors on fast neutrons, security, thermite, corium, blocking the flow cross section, thermal interaction, distribution of materials

Article Text (PDF, in Russian)

References

UDC 621.039.586

Problems of Atomic Science and Technology. Series: Nuclear and Reactor Constants", 2016, issue 5, 5:11