Dynamic reactor testing of fuel-releasing elements for safety substantiation under emergency conditions

This work discusses the layout of the experiments and briefly surveys the results of parametric capsule tests in the IGR and Gidra reactors. In these tests, VVER-1000-type fuel elements were investigated in a no-flow capsule with reactor power varying in pulses. About 140 tests were carried out from 1983 to 1988. The main goals were as follows: (1) to study the influence of the test and structural parameters on the behavior of the fuel elements, (2) to obtain experimental data on the magnitudes of the threshold failure stresses on the fuel element, (3) to develop a quantitative evaluation procedure for the fuel element parameters in the course of testing, and (4) to create an experimental data base to refine the physical models of the phenomena and to develop the corresponding mathematical models. On the whole, the primary disruption mechanisms for VVER-1000-type fuel elements found in the tests at the IGR and Gidra reactors correspond with the data obtained in the SPERT, TREAT, and NSRR reactors. No disruption (with an initial internal pressure of ∼0.1 MPa) as a consequence of cladding embrittlement was found for VVER-1000-type elements