Nuclear power stations use the energy from fission of uranium or plutonium to make electricity. Evaluating them means weighing the benefits against the problems. The main benefit is that no carbon dioxide is released while the station runs, so nuclear power does not add to global warming. A small mass of fuel releases a very large amount of energy, and the supply is reliable because it does not depend on the weather.
The problems start with waste. Used fuel and other high-level waste stay radioactive for thousands of years. It has to be sealed in containers and stored deep underground, and it must be kept safe for a very long time. Building a nuclear station and later decommissioning it are both expensive, and building takes many years.
Safety is the other concern. Serious accidents are rare, but an accident could release radioactive material over a wide area and affect people for many years. Public perception is often shaped by this fear, together with worries about waste, and opposition can delay or stop new power stations being built. A good evaluation weighs all of these and reaches a judgement.