According to the following website listing the yields of fission products for Uranium and other transuranic isotopes: https://www-nds.iaea.org/sgnucdat/c3.htm The fission product 63-Eu-155 is rare but not impossible. According to my maths, this means there must be another daughter nuclei with atomic number 29 in order to conserve charge etc. However, Copper (with atomic number 29) is not in the list of fission products, nor any element with an atomic number lower than this. Therefore, I wonder how the fission of Uranium to Europium is possible? The only way I can see this becoming possible is for Uranium to split into Europium and to release several alpha particles or protons in the process, but I have not heard of this happening. Can anyone shed any light on this?