Assessment of the critical populations at risk due to radiation exposure in structures

In preparation for a survey of radiation doses in U.S. structures, information on survey criteria, techniques, and results was reviewed and evaluated, some survey procedures and calculational methods were developed and tested, and a protocol for a nationwide survey was prepared. Measures to prevent or remedy significantly elevated doses from building materials were reviewed from the viewpoint of cost-effectiveness, application of several measures was recommended under specific conditions, and a selected method was tested. In the U.S., building materials may contain elevated levels of radionuclides if they contain shale, granite, and pumice among naturally occurring materials, and phosphate slag, phosphogypsum, and fly ash among industrial byproducts. Some additional materials have been identified in other countries. The highest gamma radiation exposure rates found in U.S. structures due to building materials are attributed to concrete that contains phosphate slag from the thermal process for phosphorus production