This Standard establishes typical long-term concentrations of principal radionuclides in fluid streams of light-water-cooled nuclear power plants for use in estimating the expected release of radioactive materials from various effluent streams. These fluid streams are: BWR reactor water and steam; PWR reactor coolant; and PWR steam generator water and steam. The concentrations in fluid streams of BWR's and PWR's are treated in a similar manner, but have different numerical values because of the basic differences between the systems. The numerical values given in this Standard are based on available data from operating plants which use Zircaloy clad uranium-dioxide fuel. The values are given for a set of reference conditions and guidance is provided for adjusting to other conditions.