PRIMITIVE meteorites such as carbonaceous chondrites (CC) and unequilibrated ordinary chondrites (UOC) have an anomalous fission xenon component1-3 which has a distinctly different fission spectrum from that of Ca-rich achondrites4,5. Although the latter is established as due to 244Pu spontaneous fission4, the origin of the former component is still debated. Further, the amount of fission xenon present in CC II-IV and some UOC is about two orders of magnitude6,7 higher than that of Ca-rich achondrites and even the maximum value of 244Pu could account only for 10% of CC fission xenon. Several mechanisms, such as carrier hypothesis8, mass fractionation9, superheavy elements6,7, and two-component trapped xenon10, have been proposed to explain the CC fission xenon. Here we attempt to determine whether some actinide isotopes with known properties could produce this excess fission xenon in the primitive chondrites.