There are 104 commercial nuclear power plants in the United States producing a whopping 806.2 TWh of electricity, in other words about 20 % of the entire electricity generation (2008). There is no doubt that the potential of nuclear energy is huge, but there are also downsides.
Before we get further into the pros and cons list, what exactly is nuclear energy? The basic gist is this: By separating an atom into two lighter atoms, there is a net loss of mass. This mass is not exactly lost, but rather transformed into massive amounts of energy. This is what is referred to as nuclear fission. By controlling these reactions we can harness the energy.
1 Relatively Low Costs
The initial construction costs of nuclear power plants are large. On top of this, when the power plants first have been built, we are left with the costs to enrich and process the nuclear fuel (e.g. uranium), control and get rid of nuclear waste, as well as the maintenance of the plant. The reason this is under advantages is that nuclear energy is cost-competitive. Generating electricity in nuclear reactors is cheaper than electricity generating from oil, gas and coal, not to speak of the renewable energy sources!
2 Base Load Energy
Nuclear power plants provide a stable base load of energy. This can work synergistic with renewable energy sources such as wind and solar. The electricity production from the plants can be lowered when good wind and solar resources are available and cranked up when the demand is high.
3 Low Pollution
It is in most cases more beneficial, in terms of the climate crisis, to replace other energy harnessing methods we use today with nuclear power. The environmental effects of nuclear power are relatively light compared to those. However, nuclear waste is potential harmful for both humans and the environment.