Nuclear Fission and How It Works in the Generation of Electricity

Nuclear fission (splitting) occurs when the nucleus of an atom of U235 Uranium is bombarded with neutrons from another source. The nucleus splits into two smaller fragments and at the same time releases additional neutrons. Some of these additional neutrons will split other U235 nuclei which in turn will release still more neutrons. This continuous splitting is a chain reaction. One product of a chain reaction is heat produced by the fragments being scattered at high speed.

The chain reaction takes place inside a containment vessel called a reactor. Control rods, made of a material that absorbs neutrons like a blotter, can stop the chain reaction instantly when inserted into the reactor fuel core.

In the generation of electricity, the only function of the nuclear reactor is to supply the heat necessary to convert water into steam. Once the steam is produced, the balance of the generating process is exactly the same as that in a fossil fueled generating plant.

Salem and Hope Creek Generating Stations PSEG Nuclear’s generating stations are located in the southern region of New Jersey on a man-made peninsula in the Delaware River. The plant includes a 740-acre site surrounded by wetlands and a variety of wildlife indigenous to the region. The complex consists of three generating stations (Salem 1, Salem 2 and Hope Creek) and is capable of producing enough electricity to power about three million homes.

THE PRESSURIZED WATER NUCLEAR REACTOR – SALEM NUCLEAR GENERATING STATION

In a pressurized water nuclear reactor, there are three separate and enclosed water loops. Within the first loop, water, under pressure to prevent boiling, flows through the reactor fuel core and is heated by nuclear fission. The heated water passes through the steam generator where it transfers its heat to the water in the second loop and is then pumped back into the reactor to be reheated. The water in the second loop boils into steam and rushes with great force into the turbine where it strikes blades causing an attached shaft to spin. The other end of the shaft spins inside a generator, producing electricity. Within the third loop, cooling water, drawn from an outside source, condenses the steam after its energy is spent. The cooling water is returned to its source while the reconverted water is pumped back to the steam generator.

THE BOILING WATER NUCLEAR REACTOR – HOPE CREEK NUCLEAR GENERATING STATION

In a boiling water nuclear reactor, there are two separate and enclosed water loops. Within the first loop, water flows through the reactor fuel core and heat generated by nuclear fission causes it to boil into steam. The steam rushes with great force through the steam line into a turbine. Once in the turbine, the steam strikes blades attached to a shaft causing it to spin.

The other end of the shaft spins inside a generator, producing electricity. A second water loop, carrying cooling water drawn from an outside source, condenses the steam when its energy is spent in the turbine. After condensation, the reconverted water is pumped back into the reactor vessel to start the heating cycle again while the cooling water is returned to its source.