Nuclear reactor makers ranking worldwide by number of reactors 2011

France’s AREVA was one of the largest builders of nuclear reactors in the world. The company specialized in nuclear power and renewable energy. However, after its insolvency, AREVA sold most of its reactors to the French utility, EDF, while nuclear propulsion and research reactors were sold to Agence des participations de l'État. Its nuclear cycle business was also separated to a new company now called Orano.

How do nuclear reactors work?

Nuclear reactors use the energy generated from splitting atoms. Uranium is the basic fuel used in nuclear reactors. This fission of uranium atoms produces energy that is harnessed as heat in the form of water or a gas and is then used to produce steam. The steam is then used to drive a turbine to produce electricity.

What about nuclear waste?

After nuclear fuel has spent about three years in a nuclear reactor generating electricity, the fuel becomes nuclear waste. This high-level waste accounts for a small volume of waste but still contains the largest share of the radioactivity levels. Nuclear fuel waste is usually removed underwater and transferred to a storage pool as water can act as both a coolant and a shield. After about five years, this waste can be transferred into dry concrete containers or remain for up to 50 years in the storage pool. In comparison, about 90 percent of nuclear waste is only lightly-contaminated and considered low-level waste. This includes items like tools and work clothing from plant operation.