How is nuclear power used to make electricity?

Answer 1

There are different types of Reactors using different methods and materials, but the basic principle is a very old one - generate heat which then turns water into steam, and then use the steam to drive a turbine generator to produce AC electricity. The difference is that an amount of nuclear material weighing less than a a couple of pounds is enough to create enough heat for driving turbines for a very long time. Nuclear fuel does not generally need to be replaced for many years.

Examples of typical reactors are a Pressurized Water Reactor, one of the most common and widely used designs, and a Boiling Water Reactor. The Russians are known to use liquid metal and liquid sodium reactors in some of their submarines.

The process I'm describing here is for a Pressurized Water Reactor, the most common design in use by the military and civilian communities.

A Nuclear Reactor uses a very small amount of fissionable material to sustain a nuclear reaction inside what's known as the Reactor Core or Vessel. The Core sits in a Containment Vessel, which among other things provides shielding from radiation, and in some reactors, holds cooling water (Coolant). The cooling water in a PWR is pressurized and constantly circulating around the Reactor core. The reaction is controlled by the insertion or removal of Control Rods, which when inserted soaks up the neutrons and slows the reaction process. As the rods are removed, the reaction process increases and more heat is generated.

Pipes containing the pressurized coolant are passed through a heat exchanger called a Steam Generator, which transfers the heat from the reactor via pipes into the SG. Cooled, condensed water passes into the SG and over the heated pipes through which the coolant flows, flashing the water instantly into pressurized steam. The pressurized steam is then passed through a Turbine Generator, which runs at very high RPM's and produces AC electricity. From there, it is either used immediately for AC equipment, converted to DC electricity for battery charging/storage, or transmitted downline to for further AC/DC use by equipment and users.

Once the steam has driven the turbine, it passes into a Condenser, where it is cooled from gaseous steam back into water. Once it has been converted back to a liquid state, it then passes back to the Steam Generator, starting the cycle all over again.

Again, though the design and safety considerations are much more complex, the basic overall principle is a very, very old one. The difference in reactor designs are primarily in how they are cooled, where the basic Heat Exchanger/Steam Generator, Turbine and Condenser loop remains essentially the same throughout the various designs. PWR's have been used for almost 50 years in the U.S. Navy, with no incidents or accidents. This is due to the extreme controls and strict compliance required by all who work with the Reactor components themselves, and those who serve aboard Nuclear Powered warships and submarines. A single mistake by an officer, for example, is generally sufficient to end that officer's Naval career. Random audits and checks are constantly performed by oversight agencies to ensure that the Navy's record continues unblemished.

Russian nuclear programs have not always been as safe or successful as their Western counterparts, because of their tendency to experiment with new designs, and use of inexperienced people to operate their reactors. Reactor shielding were known to be a problem on several Russian warships and submarines when the Soviet Union was still in existence. From these examples we've learned that Nuclear Power, when operated under strict controls by experienced people using safe designs, can provide a cheap and clean power source.

However, in the wrong hands, it can lead to disaster, as the Russians and the world experienced at Chernobyl, and the U.S. did at Three Mile Island. In both cases, design and personnel problems were at the root cause of the accidents. Chernobyl was by far the worst of the two - the town that provided for those who worked at Chernobyl, Pripyat, is now literally a ghost town. It once held over 50,000 people - it was evacuated the day following the accident, and its residents were never allowed to return. It has since become a unique insight and view into what happens to a modern town/city when it is completely abandoned by humans and left to decay.

The massive earthquake and tsunami that hit Japan and led to the Fukushima Dai-ichi accident is a good example of how well nuclear plant designs have improved, even in the face of a major natural disaster. Though the plant did release radioactive material as a result of damage to its cooling system, it was originally designed to withstand a magnitude 8.0 earthquake and waves of up to 5.7 meters (about 19'). Given that it was hit by a earthquake of magnitude 9.0 and tsunami waves of 14 meters (about 45'), the design held up pretty well given the fact that the destructive potential of the disaster was much worse than the upper limit of the design specifications.

Answer 2

Nuclear power is generated by splitting atoms in a nuclear reactor, which releases heat energy. This heat is used to produce steam that drives a turbine connected to a generator, which then converts the kinetic energy into electricity. The electricity is then transferred to the power grid for distribution to homes and businesses.