Describe nuclear fission reactors in a way a young child would understand.
A nuclear fission reactor is a special kind of machine that makes heat and electricity using really tiny things called atoms.

You see, everything in the world is made up of tiny things called atoms. Atoms are like building blocks that make up everything around us, like air, water, and even you and me!

Some atoms, like the ones found in a special type of rock called uranium, can be split apart into smaller pieces in a process called nuclear fission. When this happens, a lot of heat and energy is released.

In a nuclear fission reactor, uranium atoms are split apart inside a special container called a reactor core. The heat that's released from this process is used to make steam, which then turns a big wheel called a turbine. The turbine is connected to a generator, which makes electricity that can be used to power homes, schools, and businesses.

So, that's basically how a nuclear fission reactor works - by splitting apart tiny atoms to create heat and electricity!
That was really helpful, thanks. What implications might this tech have on the future of civilization if it becomes cheap and ubiquitous?
Nuclear fission technology has the potential to play a significant role in shaping the future of civilization by providing a reliable and stable source of energy. If it becomes cheap and ubiquitous, it could help to meet the growing energy demands of the world while also reducing our reliance on finite resources such as coal, oil, and natural gas.

However, there are also potential downsides to the widespread use of nuclear fission technology. One of the biggest concerns is the issue of nuclear waste, which can remain radioactive and dangerous for thousands of years. If not properly managed and disposed of, it could pose a serious threat to public health and the environment.

Another concern is the risk of nuclear accidents, which can have catastrophic consequences for both people and the environment. Additionally, nuclear reactors can be targeted for theft or sabotage, which could result in the release of radioactive material and cause widespread harm.

Despite these potential risks, many experts believe that nuclear fission technology can be a safe and effective source of energy if it is properly regulated and managed. However, it is important to consider the potential impacts and weigh the benefits against the risks before making any decisions about the widespread use of this technology.