Environmental radiation monitoring in Korea can be categorized as (1) nationwide monitoring program and (2) monitoring program for nuclear facilities. The former is designed to quickly detect any abnormal situation in environmental radioactivity levels. The latter has the objective of evaluating environmental radioactivity levels resulting from the operation of nuclear facilities. This paper describes the two monitoring programs, how they are implemented, items of being measured, analytical techniques, quality control programs and R&D activities associated with the monitoring. Also, some of the latest data obtained by the monitoring programs are introduced.
Brief history and current status of activation analysis in Korea are described. About 120 papers have been published since the first paper was reported in 1960. They are sorted out into 5 consecutive periods according to the publication year, and typical feature of each period is described.
Authors:Chang Lee, Mun Kang, Wanno Lee, Geun Choi, Young Cho, Hee Kim, and Kun Chung
210Po in the daily diet in Korea was analyzed and the ingestion dose from an intake of 210Po was estimated by considering the dietary habit of a Korean person. The 210Po concentrations of a leafy vegetable (0.36 Bq·kg−1 for lettuce) in the terrestrial food were higher than those of grain, whereas Chinese cabbage had a lesser 210Po concentration (0.019 Bq·kg−1). The 210Po concentration of the animal product was similar to those detected in the grain and vegetable. The 210Po concentrations in the shell and crustaceous were high from 19.1 to 33.0 Bq·kg−1, however, its value fell in the overall range of the reported values. The effective dose from 210Po for an adult from the Korean population was about 269.4 μSv·y−1. Nearly 80% of the ingestion dose from the intake of 210Po was attributed to the consumption of seafood. It suggests that the marine food ingestion is a critical pathway for natural
210Po to the Korean population.
Authors:Yoon Yoon, Kil Lee, Kang Chung, Myong Yang, and Kun Kim
Instrumental neutron activation analysis (INAA), ICP/MS and XRF were applied for the characterization of relative locales of Korean old potteries, which had three different era and four regional characters. From the elemental analysis, two major elements such as Fe, Ti and some minor elements such as Cr, Sc, Zr were supposed to the main contributing factors for the regional classification. And the contents of rare earth elements, such as Eu and La were different in each pottery.
For age determination, the single aliquot regenerative-dose (SAR) method was applied to quartz from archaeological materials, using luminescence stimulated by blue light. The quartz samples were extracted from sediment from the hydroponic farm related to rice cultivation in an area of archaeological interest in Buyeo, south of Seoul. The optically stimulated luminescence (OSL) dates obtained offered good agreement with the ages derived by typological assessment and 14C ages. These ages should contribute significantly to interpretation of the history of rice cultivation in Korea.
Authors:C. S. Park, G. M. Sun, S. H. Byun, and H. D. Choi
The new PGAA facility using diffracted neutron beam was developed in Korea. The basic characteristics of the facility were studied in detail. A general formalism of the k0 factor as extended to non-1/v absorber and arbitrary neutron spectrum was discussed and the actual data for Cd, Sm, Eu, Gd have been measured and determined successfully owing to the simple nature of the diffracted neutron spectrum. The k0 factors for B, N, Si, P, S and Cl were also determined and showed consistent results with previously reported ones. At an early stage, feasibility of boron concentration analysis and measurement of thermal neutron capture cross sections has been studied. The PGAA facility is now open to users. A considerable amount of beam time is already dedicated to studies on the elemental analysis.
A one day representative mixed diet of an adult Korean was collectedfrom the data based on the food intake of 108 healthy subjects between theages 20 and 50. Sampling for the Korean total diet was carried out by usinga market basket study based on the Korean standard food consumption schemereported by the Korean Nutrition Society. Average consumption frequency ofdifferent food items for a one day representative mixed diet of an adult Koreanand the amount of each item to prepare a one day Korean representative totaldiet are surveyed. The analytical methods involve both instrumental and radiochemicalneutron activation techniques developed for the determination of the elementsCs, I, Sr, Th and U in various kinds of food samples. Concentrations of traceelements including 5 important elements for radiological protection, U, Th,Cs, Sr and I in the Korean total diet and the 4 most frequently consumed Koreanfoodstuffs have been analyzed by neutron activation analysis. Detection limitsfor U, Th, Sr and I were improved to ppb levels by radiochemical separationafter neutron irradiation. Five biological NIST reference materials were alsoanalyzed for quality control of the analysis. Seventeen trace elements inthe Korean total diet and four Korean representative foodstuffs were alsoanalyzed quantitatively by instrumental neutron activation analysis.
The cumulative depositions of137Cs,90Sr and fallout Pu in the volcanic ash soil of Korea were determined. The average accumulated depositions of137Cs,90Sr and fallout Pu in the volcanic soil were much higher than those in other forest sites of Korea. From depth profiles, it
was found that137Cs,90Sr and239,240Pu in the volcanic soil are more mobile than those in other forest sites of Korea, and that the downward movement of90Sr is faster than137Cs and239,240Pu. A significant correlation was found between the concentration of137Cs and those of90Sr and239,240Pu. The activity ratios of238Pu/239,240Pu and241Pu/239,240Pu in soils are close to those observed in the cumulative deposit from the global fallout of nuclear weapon testings.
Authors:A. Ringbom, Klas Elmgren, Karin Lindh, Jenny Peterson, Theodore Bowyer, James Hayes, Justin McIntyre, Mark Panisko, and Richard Williams
Following the claimed nuclear test in the Democratic People’s Republic of Korea (DPRK) on October 9, 2006, and a reported
seismic event, a mobile system for sampling of atmospheric xenon was transported to the Republic of South Korea (ROK) in an
attempt to detect possible emissions of radioxenon in the region from a presumed test. Five samples were collected in the
ROK during October 11–14, 2006 near the ROK–DPRK border, and thereafter transported to the Swedish Defense Research Agency
(FOI) in Stockholm, Sweden, for analysis. Following the initial measurements, an automatic radioxenon sampling and analysis
system was installed at the same location in the ROK, and measurements on the ambient atmospheric radioxenon background in
the region were performed during November 2006 to February 2007. The measured radioxenon concentrations strongly indicate
that the explosion in October 9, 2006 was a nuclear test. The conclusion is further strengthened by atmospheric transport
models. Radioactive xenon measurement was the only independent confirmation that the supposed test was in fact a nuclear explosion
and not a conventional (chemical) explosive.
Authors:Yong Chung, Young Chung, Kyung Cho, and Joung Lee
Trace and toxic elements in Certified Reference Material (CRM) made of Korean rice at the Korea Research Institute of Standards and Science have been analyzed by Instrumental Neutron Activation Analysis (INAA). Data intercomparison from the measurement with those of Atomic Absorption Spectrometry (AAS) and Induced Coupled Plasma Spectrometry (ICPS) has been studied. The powdered samples were sterilized at 1.5·106 rad in the bottles using a60Co source after sieving and spiking to specific elements such as As, Cd, Cr, Cu and Hg and then the homogeneity of samples was assessed. Rice flour (SRM 1568a) and standard solutions made by the National Institute of Standards Technology (NIST) were used to construct the calibration curves for the INAA and the chemical methods, respectively. The uncertainties and concentration of constituent elements were determined and the possibility of their use for analytical quality control was considered.