A nuclear power generating station operates on the same principle as a conventional fossil-fueled (oil or coal) power plant, except that the heat generation is provided by nuclear fission rather than combustion. The heat liberated in either process (fission or the combustion of fossil fuel) is used to convert water into steam. The steam enters a turbine which is connected to a generator that produces electric current for commercial distribution.

A byproduct of the fission process is the production of radioactive gases in the fuel. These are called fission gases. Nuclear particles (neutrons) are also absorbed by the water coolant and structural materials producing radioactive activation products. A typical power reactor may experience a small number of pinhole leaks in the fuel over its operating life. Radioactive gases may escape the fuel rod through these leaks and enter the water coolant. As a result, radioactive fission gases are present to some extent in the water coolant of the reactor at all times.

Oyster Creek and Hope Creek use "Boiling Water Reactors" (BWR) to convert the water into steam. Salem 1 and Salem 2 use "Pressurized Water Reactors" (PWR) to convert the water into steam. While there are many differences between BWRs and PWRs, for the purposes of this document, the most important characteristic is the radioactivity released from the plant to the environment. These releases are in the form of gaseous and liquid effluents, consisting of predominantly short lived, inert noble gases and lesser amounts of tritium and fission products.

The radiation released to the air or water disperses and decays. The decay of radioactive elements is measured in terms of half life. Half lives vary depending on the particular radionuclide involved and can be on the order of seconds, minutes, hours, days, or years. Less than one percent of the radioactive material initially present remains after seven half lives have passed.

Laboratory analyses of the radioactive pollutants discharged from the nuclear power stations have demonstrated that Cesium-137, Iodine-131 and Cobalt-60 are the dominant radionuclides that may have an impact on the general population. Dominant in this context means that either they have relatively longer half lives and therefore may be present in trace amounts in the environment as in the case of Cesium-137 and Cobalt-60 or they represent potentially significant exposure pathway as in the case of Iodine-131.

Traces of radionuclides dispersed into the environment during the normal operation of nuclear facilities may contribute some radiation exposure to the population. The technical data collected through the ESMP define the quantities and characteristics of the radioactive discharges released and identify the critical pathways which have the potential for radiation doses received by the population.

Oyster Creek Nuclear Generating Station

Salem 1 & 2 and Hope Creek Nuclear Generating Stations (Artificial Island)