Fusion And Fission

The fission of plutonium nuclei typically occurs when the nucleus is bombarded with slow neutrons (also called thermal neutrons). These neutrons have a lower energy and are more likely to be captured by the plutonium nucleus, causing it to become unstable and undergo fission.

• Fast neutrons have high energy, and while they can cause fission, they are less effective than slow neutrons.
• Slow neutrons are effective in initiating fission reactions in heavy nuclei such as plutonium-239.
• Deuterons and alpha particles are not typically involved in fission reactions with plutonium nuclei.

Thus, the correct answer is: