Water is essential to sustaining human life. It's also essential to the production of electricity at nuclear power plants which are designed to use as little water as possible.
At its most basic function, in most nuclear power plants, heated water is circulated through tubes in steam generators, allowing the water in the steam generators to turn to steam, which then turns the turbine generator and produces electricity. Water is then used to cool the steam and turn it back into water. And the whole process starts over.
Water is also a natural barrier and gives protection against radioactive materials. But there's more to water use at a nuclear plant than turning to steam or filling an Olympic-sized pool to cover used fuel.
Nuclear power plants use water in a variety of ways:
- Transferring heat (water circulates through the core of the reactor and picks up heat given off through the fission process)
- Cooling steam back into water (condenser cooling water, used to cool unused steam, comes from either cooling towers or a process called once-through cooling)
- Cooling used fuel (used nuclear fuel is stored in a steel-lined pool filled with borated water, which acts as a natural barrier for radiation from the used fuel). The pool is typically around 40 feet deep and constructed of concrete, and the water completely covers the used fuel, in most cases there is more than 25 feet of water above the used fuel.
- Other usages include water reserved and stored to serve as a backup source of water for the reactor core in the event of an emergency (to cool the reactor core
Nuclear plant cooling systems have regulatory requirements established by the U.S. Environmental Protection Agency (EPA), under authority provided by the federal Clean Water Act. Nuclear plants are located on or near bodies of water and maintain and protect the surrounding ecosystem. Plants work closely with local wildlife agencies to establish wildlife protection and good environmental stewardship.