Curium-244 is a highly radioactive minor actinide that decays relatively rapidly (half-life: 18.1 years).

Today, Plutonium 238 is usually prepared by the irradiation of neptunium 237, a minor actinide produced in nuclear reactors, that can be recovered from spent nuclear fuel during reprocessing, or by the irradiation of americium in a reactor.

Pure Pu-238 is prepared by irradiation of neptunium-237, one of the minor actinides that can be recovered from spent nuclear fuel during reprocessing, or by the irradiation of americium-238.

Pure Pu-238 is prepared by irradiation of neptunium-237, one of the minor actinides that can be recovered from spent nuclear fuel during reprocessing, or by the irradiation of americium-238.

This simple calculation shows that the fission of a minor actinide reduces the radiotoxicity by a factor of 10 after 10 years, 200 after 300 years and 100,000 after 600 years.