information:extraction
Radionuclides

Curium is one of the most radioactive isolable elements. Its two most common isotopes Cm and Cm are strong alpha emitters (energy 6 MeV); they have fairly short half-lives, 162.8 days and 18.1 years, and give as much as 120 W/g and 3 W/g of heat, respectively. Therefore, curium can be used in its common oxide form in radioisotope thermoelectric generators like those in spacecraft. This application has been studied for the Cm isotope, while Cm was abandoned due to its prohibitive price, around 2000 USD/g. Cm with a ~30-year half-life and good energy yield of ~1.6 W/g could be a suitable fuel, but it gives significant amounts of harmful gamma and beta rays from radioactive decay products. As an α-emitter, Cm needs much less radiation shielding, but it has a high spontaneous fission rate, and thus a lot of neutron and gamma radiation. Compared to a competing thermoelectric generator isotope such as Pu, Cm emits 500 times more neutrons, and its higher gamma emission requires a shield that is 20 times thicker— 2 inches (51 mm) of lead for a 1 kW source, compared to 0.1 inches (2.5 mm) for Pu. Therefore, this use of curium is currently considered impractical.

A more promising use of Cm is for making Pu, a better radioisotope for thermoelectric generators such as in heart pacemakers. The alternate routes to Pu use the (n,γ) reaction of Np, or deuteron bombardment of uranium, though both reactions always produce Pu as an undesired by-product since the latter decays to U with strong gamma emission. Curium is a common starting material for making higher transuranic and superheavy elements. Thus, bombarding Cm with neon (Ne), magnesium (Mg), or calcium (Ca) yields isotopes of seaborgium (Sg), hassium (Hs and Hs), and livermorium (Lv, Lv, and possibly Lv). Californium was discovered when a microgram-sized target of curium-242 was irradiated with 35 MeV alpha particles using the 60-inch (150 cm) cyclotron at Berkeley:

Only about 5,000 atoms of californium were produced in this experiment.

The odd-mass curium isotopes Cm, Cm, and Cm are all highly fissile and can release additional energy in a thermal spectrum nuclear reactor. All curium isotopes are fissionable in fast-neutron reactors. This is one of the motives for minor actinide separation and transmutation in the nuclear fuel cycle, helping to reduce the long-term radiotoxicity of used, or spent nuclear fuel.