Which of the following features would you associate with a self-sustaining nuclear chain reaction?

1. In which products are of comparable mass to fission nuclei.
2. In which the average number of neutrons released per nuclear that bombard other nuclei is more than one.

Nuclear fission is the process of splitting a nucleus into roughly equal parts, and releasing energy and neutrons in the process. If these neutrons are captured by another unstable nucleus, they can fission as well, leading to a chain reaction. The average number of neutrons released per nucleus that go on to fission another nucleus is referred to as k. Values of k larger than 1 mean that the fission reaction is releasing more neutrons than it absorbs, and therefore is referred to as a self-sustaining chain reaction.