Study of Nuclide Field Behaviour in Reactor with Continuously Changing Core Parameters

Abstract

This work first deals with the reactor concept INCOGEN. which is a small (about 40 MWth) advanced fission reactor for INherently safe CO-GENeration of heat and electricity. The reactor is based on the high-temperature helium-cooled pebble-bed reactor. For ease of operation and cost reduction fuel is continuously added over a period of more than 10 Years. Study of 3-D burnup fields in the INCOGEN reactor is the primary purpose of the current research. A new burnup option of the 3-D PROMETHEUS core analysis code system was used fer this study. This option incorporates a number of unique features originating from the general purpose PROMETHEUS code system, the SAS6 module as added to the SCALE code system. and the ORIGEN burnup library updated on the basis of JEF2.2. As a result. detailed burnup data is obtained with higher accuracy and efficiency. Subsequently. similar simulation tools are used to investigate the reduced volume. activity, and lifetime of radioactive waste in a fuel cycle strategy that incorporates on-site electrorefining of the spent fuel when it is compared to the more conventional once-through fuel cycle scheme. Significant reductions in the waste activity and the duration of its existence by recycling all but the neutron-absorbing fission products back into the reactor core allows for the possibility of on-site storage as an alternative to permanent disposal, while not isolating plutonium nor introducing any attendant increased proliferation risk.