title: Analytical evaluation of natural radionuclides and their radioactive equilibrium in raw materials and by-products.
abstract: An investigation into the distribution of natural radionuclides and radioactive secular equilibrium in raw materials and by-products in a domestic distribution was conducted to deduce the optimum conditions for the analytical evaluation of natural radionuclides for (238)U, (226)Ra, and (232)Th using a gamma-ray spectrometer and inductively coupled plasma mass spectrometer (ICP-MS). The range of the specific activities of natural radionuclides was first evaluated by analyzing (228)Ac and (214)Bi, which are (232)Th and (226)Ra indicators, respectively, in about 100 samples of raw materials and by-products through a gamma-ray spectrometer. From further experiments using several samples selected based on the results of the distribution of natural radionuclides, the validation of their analytical evaluations for the indirect measurements using a gamma-ray spectrometer and direct measurements using ICP-MS was assured by comparing their results. Chemically processed products from the raw materials, such as Zr sand and ceramic balls, were generally shown for the type of bead and particularly analyzed showing a definite disequilibrium with above a 50% difference between (238)U and (226)Ra in the uranium series and (232)Th and (228)Ra in the thorium series.
authors.affiliation: Environmental Radioactivity Assessment Team, Korea Atomic Energy Research Institute, Daejeon 305-353, Republic of Korea. Electronic address: yyji@kaeri.re.kr.
authors.forename: Young-Yong
authors.initials: YY
authors.lastname: Ji
authors.affiliation: Environmental Radioactivity Assessment Team, Korea Atomic Energy Research Institute, Daejeon 305-353, Republic of Korea.
authors.forename: Kun Ho
authors.initials: KH
authors.lastname: Chung
authors.affiliation: Environmental Radioactivity Assessment Team, Korea Atomic Energy Research Institute, Daejeon 305-353, Republic of Korea.
authors.forename: Jong-Myoung
authors.initials: JM
authors.lastname: Lim
authors.affiliation: Environmental Radioactivity Assessment Team, Korea Atomic Energy Research Institute, Daejeon 305-353, Republic of Korea.
authors.forename: Chang-Jong
authors.initials: CJ
authors.lastname: Kim
authors.affiliation: Environmental Radioactivity Assessment Team, Korea Atomic Energy Research Institute, Daejeon 305-353, Republic of Korea.
authors.forename: Mee
authors.initials: M
authors.lastname: Jang
authors.affiliation: Environmental Radioactivity Assessment Team, Korea Atomic Energy Research Institute, Daejeon 305-353, Republic of Korea.
authors.forename: Mun Ja
authors.initials: MJ
authors.lastname: Kang
authors.affiliation: Department of Physics Education, College of Education, Kongju National University, Kongju 314-701, Republic of Korea.
authors.forename: Sang Tae
authors.initials: ST
authors.lastname: Park
keywords: By-products; Disequilibrium; NORM; Natural radionuclides; Raw materials