The experimental test programme for the study of high burnup PWR rods under RIA conditions in the CABRI core

The CABRI facility mainly consists of an experimental reactor cooled with water, with a cell in its center which is the in-pile part of a sodium loop. The CABRI core offers the feasibility of rapid and energetic power pulses, therefore tests are now performed for the study of the high burnup PWR fuel rods under RIA conditions. The instrumentation of the test section in which the test rod is introduced includes flowmeters, pressure transducers, microphones, thermocouples and a clad elongation transducer. The test programme includes up to now nine tests, among which four have been performed, in the frame of a sharp pulse. The first test rod (REP Na1 test) was taken from a commercial fuel rod irradiated in an EdF power plant leading to a maximum burnup of 63.8 GWd/t U for the re-fabricated test rod. The test REP Na2 used a full length rod with a maximum burnup of 33 GWd/t U. The REP Na3 test rod led to a non-failure test. The REP Na5 test was performed on a EdF rod; no rupture was observed and only a slight rod deformation can be deduced from experimental signals. (R.P.)