A study of the criticality safety design for the metal fuel recycle system (2)

This report describes a study about the criticality safety design for the large-scale electrorefiner, which is designed in the activities of 'The Design Study of Metal Fuel Recycle System (2002)', under the collaboration with Central Research Institute of Electric Power Industry, and the continuation of 'A Study of the Criticality Safety Design for the Metal Fuel Recycle System', which was published in September 2003. The report includes a detail design and quantitative criticality parameter limits based on the mass control supported with chemical form control' concept which is proposed in 'A Study of the Criticality Safety Design for the Metal Fuel Recycle System'. Furthermore procedures to determine these limits are presented in the report. Next we studied contingencies anticipated under the critical control and executed quantitative criticality safety analyses of models based on these abnormal conditions. The analytical result shows adequate safety margins are maintained in the criticality safety design even if many of these contingencies could occur. However the event of abnormal generation of insoluble led to intolerable results on the design if extremely strict modeling would be imposed to uncontrollable criticality parameters like geometry. Moreover we propose a concept of material transfer and production control system, we call it as 'Operation by wire', which all the equipment and handling machines are electrified and the control system provides completely automated process control and operation. The control system eliminates human errors and violations like over batching error or transfer error in the commercial scale metal fuel recycle system with complicated operation procedures. Finally technical issues in order to substantialize the concept of mass control supported with chemical form control in the recycle system are indicated. (author)