fuel cycle will be plutonium-239 which has a 24,400 year halflife. In other words, in 240,000 years the inventory of this hazardous material would be reduced by only a factor of 1000 due to natural radioactive decay. This material must be isolated from the environment in perpetuity. Ili. Existine Standards for Plutonium Exsosure Radiation exposure standards have been established because radiation is known to produce cencer and genetic mutations in individuals irradiated. The mutations can in turn cause genetic defects in subsequent generations. Tae intenc of the exposure standards is to limit this biological danace. The macnituce of the biological effect has been shown to be related to the radiation dose. dose the greater the effect. The higher the Therefore, the primary radia- tion exposure standard is one that limits the radiation ou ose. This orimary standard is generally referred to as the maximum permissible dose and is given in units of ren/yr. wa snall discuss the nature of this unit subsequently. An individual can be exposed to radiation from sources that are external to his body as, for example, an X-ray machine or irom radionuclides which emit X-ray like radiation deoosited on tne ground (this occurred with fallout from natlear weapon tests). Alternacely, an individual can be