DESIGN AND MODELLING OF OXIDE FUEL FOR INCINERATION OF AMERICIUM AND PLUTONIUM IN AN EXPERIMENTAL ADS
The interest to the accelerator-driven subcritical systems (ADS) devoted to the incineration of plutonium and minor actinides is a subject of study around the world. Since 1997, the Belgian Nuclear Research Centre SCK·CEN is performing the pre-design studies aiming at the development of a small experimental ADS called MYRRHA which could be a step towards a prototype design of an ADStransmuter. In the present article, some results of the preliminary modelling of the behaviour of the fuel pins, filled with (Am0.5Pu0.5)O2-x dissolved in ThO2 matrix and with the same fuel in YSZ matrix, under typical ADS operation conditions are discussed and compared with the behaviour of MOX. Modelling has been performed with the fuel performance code MACROS-II which is under development and testing at SCK·CEN. A care was taken to model correctly the re-distribution of transuranium elements, fission products and helium within the fuel pellets and to their impact on the fuel performances.
MA AND LLFP TRANSMUTATION PERFORMANCE ASSESSMENT IN THE MYRRHA
A typical fast sub-critical core configuration dedicated to MA and LLFP transmutation studies has been defined containing loaded with 605.5 kg (heavy metal) of highly Pu-enriched MOX (U-Pu) fuel, 18.089 kg of MA and 24.70 kg of Tc. The core was shown to achieve a primary source neutron multiplication factor, ks, of 0.962 (keff = 0.956) yielding, for a 5 mA proton beam, a thermal power of 53.7 MW. The performances of that core has been assessed as to it potential to transmute the loaded MA and LFFFP considering a one year operation cycle consisting of 3 times 90 effective full power days of irradiation with 30 days shut-down in between
Analysis of the ATW fuel cycle using the REBUS-3 code system.
Partitioning and transmutation strategies are under study in several countries as a means of reducing the long-term hazards of spent fuel and other high-level nuclear waste. Various reactor and accelerator-driven system concepts have been proposed to transmute the long-lived radioactive nuclei of waste into stable or short-lived species. Among these concepts, the accelerator-driven transmutation of waste (ATW) system has been proposed by LANL for rapid destruction of transuranic actinides and long-lived fission products ({sup 99}Tc and {sup 129}I).The current reference ATW concept employs a subcritical, liquid metal cooled, fast-spectrum nuclear subsystem. Because the discharged fuel is recycled, analysis of ATW nuclear performance requires modeling of the external cycle as well as the in-core fuel management. The fuel cycle analysis of ATW can be performed rigorously using Monte Carlo calculations coupled with detailed depletion calculations. However, the inefficiency of this approach makes it impractical, particularly in view of (a) the large number of fuel cycle calculations needed for design optimization and (b) the need to represent complex in-core and out-of-core fuel cycle operations. To meet the need for design-oriented capabilities, tools previously developed for fast reactor calculations are being adapted for application to ATW. Here we describe the extension and applicationmore » of the REBUS-3 code to ATW fuel cycle analysis. This code has been extensively used for advanced liquid metal reactor design and analysis and validated against EBR-II irradiation data.« less