Development of Molten Corium Using An Exothermic Chemical Reaction for the Molten-Fuel Moderator-Interaction Studies at Chalk River Laboratories

摘要

Atomic Energy of Canada Limited (AECL) has partnered with Argonne National Laboratory to develop a corium thermite prototypical of CANDU material and test the concept of ejecting ~25 kg of the molten material from a pressure tube with a driving pressure of 10 MPa. This development program has been completed and the technology transferred to AECL. Preparation for the molten-fuel moderator-interaction tests at AECL's Chalk River Laboratories is well underway. A mixture of 0.582 U/0.077 U_3O_8/0.151 Zr/0.19 CrO_3 (wt%) as reactant chemicals has been demonstrated to produce a corium consisting of 0.73 UO_2/0.11 Zr/0.06 ZrO_2/0.10 Cr (wt%) at ～2400°C. This is comparable to the target CANDU specific corium of 0.9 UO_2/0.1 Zr (wt%), with limited oxidation. The peak melt temperature was confirmed from small-scale thermitic reaction tests. Several small-scale tests were completed to qualify the thermite to ensure operational safety and a quantifiable experimental outcome. The proposed molten-fuel moderator-interaction experiments at Chalk River Laboratories will consist of heating the thermite mixture inside a 1.14-m long insulated pressure tube. Once the molten material has reached the desired temperature of ～2400°C, the pressure inside the tube will be raised to about 10 MPa, and the pressure tube will fail at a pre-machined flaw, ejecting the molten material into the surrounding tank of water. The test apparatus, instrumentation, data acquisition and control systems have been assembled, and a series of successful commissioning tests have been completed.