New solutions to the problem of handling long-lived radionuclides

Department of the Atomic Energy Industry.     

Combined processing scheme of WWER-1000 spent nuclear fuel: 1. Thermochemical breaking-up of fuel claddings and voloxidation of fuel

Within the framework of the development of a combined scheme for processing WWER-1000 spent nuclear fuel, head operations such as chemical breaking-up of fuel cladding and voloxidation of the fuel with removal of volatile fission products were studied experimentally.     

Prospective Large-Scale Transmutation of Fission Iodine

The effective neutron capture cross section of ¹²⁹I was determined at irradiation of 11.3±0.55 mg of KI (83.5% ¹²⁹I and 16.5% ¹²⁷I) for 6 h in a V10 channel of the beryllium reflector of VVR-M water-cooled water-moderated reactor (PINF) at average power of 12 MW. The neutron spectrum was measured by the activation procedure. For this purpose a series of thermal, resonance, and threshold detectors and a weighed portion of iodine were irradiated. The neutron spectrum was restored from the -ray spectra of these samples by the best fit procedure. The neutron capture cross section of ¹²⁹I, averaged over the neutron spectrum in the beryllium reflector of VVR-M reactor, was 17.8±3.2 b. The activities of products formed from a model ¹²⁷I portion of iodine were irradiated. The neutron spectrum was restored from the -ray spectra of these samplesby the best fit procedure. The neutron capture cross section of ¹²⁹I, averaged over the neutron spectrum in theberyllium reflector of VVR-M reactor, was 17.8±3.2 b. The activities of products formed from a model 127Isample irradiated in a loop of VVR-M reactor under steady-state conditions were calculated.     

Combined processing scheme of WWER-1000 spent nuclear fuel: 2. Experimental trial of extraction processing of fluoride cinder

Several stages of the combined process for WWER-1000 spent fuel reprocessing are experimentally tested, including dissolution of fluoride cinder formed after fluoridation of the fuel and distillation of the essential part of uranium hexafluoride, and also separation and purification of plutonium, neptunium, and residual uranium.