Its precursor 135Xe has a high fission product yield (e.g. 6.3333% for 235U and thermal neutrons) but also has the highest known thermal neutron capture cross section of any nuclide. Because of this, much of the 135Xe produced in current thermal reactors (as much as >90% at steady-state full power) will be converted to stable 136Xe before it can decay to 135Cs. Little or no 135Xe will be destroyed by neutron capture after a reactor shutdown, or in a molten salt reactor that continuously removes xenon from its fuel, a fast neutron reactor, or a nuclear weapon.