Numerical analysis on element creation by nuclear transmutation of fission products 后印本

摘要: A burnup calculation was performed to analyze the Après ORIENT process, which aims to create highly-valuable elements from fission products separated from spent nuclear fuels. The basic idea is to use nuclear transmutation induced by a neutron capture reaction followed by a β^- decay, thus changing the atomic number Z of a target element in fission products by 1 unit. LWR (PWR) and FBR (MONJU) were considered as the transmutation devices. High rates of creation were obtained in some cases of platinum group metals (⁴⁴Ru by FBR, ⁴⁶Pd by LWR) and rare earth (⁶⁴Gd by LWR, ⁶⁶Dy by FBR). Therefore, systems based on LWR and FBR have their own advantages depending on target elements. Furthermore, it was found that creation rates of even Z’ (=Z+1) elements from odd Z ones were higher than the opposite cases. This creation rate of an element was interpreted in terms of "average 1-group neutron capture cross section of the corresponding target element ⟨_cZ⟩" defined in this work. General trends of the creation rate of an even (odd) Z’ element from the corresponding odd (even) Z one were found to be proportional to the 0.78th (0.63th) power of ⟨_cZ⟩, however with noticeable dispersion. The difference in the powers in the above analysis was explained by the difference in the number of stable isotopes caused by the even-odd effect of Z.