Activated concrete represents the greatest volume of radioactive materials produced during the dismantling operations of a PWR reactor. For heavy barytes concrete, 133Ba is the dominating γ nuclide whereas in the rebars, it is the 60Co isotope.
During the dismantling of the BR3 PWR reactor, we studied various aspects of the radioactive concrete issue:
• the characterization of the activation depth and its modelization;
• the efficiency of various demolition techniques and their application on real scale mock-ups;
• the active testing and use of various dismantling and demolition techniques among which the remote controlled jack hammer and the diamond cutting techniques were the most extensively used.
As alternative to the conditioning of the radioactive concrete as radioactive waste using the classical cement embedding strategy, we started an extensive R&D programme on the the recycling of the radioactive concrete.
The basic idea is to perform a pretreatment of the radioactive concrete so that it can be re-used as aggregates for the fabrication of “radioactive grout”. This grout is then used for the conditioning of metallic radioactive waste. We demonstrated that it is technically feasible to prepare a good quality grout using heavy radioactive concrete as raw material mixed with fresh cement.