Preparation of computer codes for analyzing sensitivity coefficients of burnup characteristics

not registered; not registered; Sanda, Toshio*

To commertialize LMFBR, they are important subjects of research and development to improve the accuracy in neutronic design of large LMFBR cores and to make be able to design highly efficient core more rationaoy. The adjusted library has been made by being reflected the result of critical experiment of the JUPITER, etc. effectively as much as possible by using the cross-sections adjustment method based on the probabilistic theory. And the distinct improvement of the accuracy in neutronic design of large LMFBR cores has been achieved. In the design of large LMFBR cores, however, it is important to accurately estimate not only neutronic characteristics, for example, reaction rate distribution and control rod worth but also burnup characteristics, for example, burnup reactivity loss, breeding ratio and so on. Therefore the objective of the work is to improve the prediction accuracy for burnup characteristics using many burnup data of "Joyo" effectively. For the objective computer codes for analyzing sensitivity coefficients of burnup characteristics were prepared and cross-sections adjustment using burnup data of "Joyo" was done and the effect for the improvement of the accuracy for burnup characteristics was estimated. The results are as follows: (1)The computer codes which could analyze sensitivity coefficients of burnup characteristics of LMFBR taking into consideration plural cycles and refueling were prepared and their adequacy was made sure by comparing with direct calculations. (2)It was clarified that it is possible to improve the accuracy of burnup characteristics without affecting statically neutronic characteristics so much by applying the burnup characteristics to cross-sections adjustment.