Check that the nuclides ²³⁹Pu, ²³³U, and ²⁴¹Pu satisfy the four conditions listed in §18.3.3 for being fissile. A few other actinides Z > 92– nuclei with – produced in reactors are also fissile. See if you can find one or two. Check out the isotopes of curium (Z = 96) and/or californium (Z = 98). Explain what information you would need in order to decide for sure if a given nuclide is fissile.