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  • Author or Editor: C. Chung x
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Abstract  

Due to the mismanagement of nuclear waste as well as heat exchanger degradation for the primary coolant of the one megawatt nuclear research reactor, the fission product137Cs has been leaking to the environment ever since 1969. In the past thirty years, the long-lived137Cs was accumulated and eventually trapped in the mud of the discharge pond right in front of the waste storage and the reactor facility. The distribution of137Cs in mud was measured and contour-mapped to reveal the migration of trace levels of137Cs in a period of three decades.

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Abstract  

Two weeks after the Chernobyl Nuclear Power Plant accident, a substantial increase in radioactivity above normal background levels was observed in various samples taken in Taiwan, R. O. C., which is 7600 km from Chernobyl. The131I concentrations in grass, rainwater, and milk were monitored continuously in succeeding weeks and correlations with weather conditions are discussed. Levels of radiation fallout over Taiwan due to the Chernobyl accident are much lower than the response levels recommended by local authorities and pose no danger to the public.

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Abstract  

The popular areca nuts were sampled and their stuffed white and red lime were collected simultaneously from four marketplaces in Taiwan in different growing seasons. Samples of areca nut were treated via homogenizer prior to freeze drying, about 100–150 mg each of the areca nut and lime were packed into PE bag. Samples were irradiated with neutron flux about 1012 n·cm–2·s–1. A total of 17, 18, and 13 elements was analyzed with INAA for white lime, red lime, and areca nut, respectively. The results indicated that Ca have the highest concentration in both limes. Most elements in collected samples have wide range of concentrations among different seasons and marketplaces. It is suggested that the elemental concentration of areca nut and limes exists in divergence originated from various farms in Taiwan. In addition, four elements of Ca, Fe, Mg, and Sc are probably overtaken by persons having chewing habit of areca nut and their effects on oral cancer are discussed.

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Abstract  

The kinetic distribution of64Cu,75Se, and69mZn radioactive tracers were determined in tissues of mice bearing ascites tumors and healthy ones. The HPGe gamma-ray spectrometric detection system was used for radionuclide analysis in tissues which were sampled at various periods after tracer injection during ascitic tumor growth. Significantly different distribution of64Cu,75Se, and69mZn were found in colon, small intestine, and liver of tumor-bearing mice. There was a dcerease of75Se in ascites and blood of tumor-bearing mice. The64Cu and69mZn concentration varied significantly in kidneys, and a similar effect was observed in the spleen for64Cu, too. A distinct variation of tracer distribution is also found at different stages after treatment. The results are discussed within the context of a correlation between elemental concentration and tumor-growth.

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Abstract  

The contents of twelve minor and trace elements in liver, ascites, and blood of sarcoma-180 tumor-bearing mice were determined by instrumental neutron activation analysis at various tumor growing stages. Biological samples were irradiated by reactor neutrons and subsequently subject to direct analysis using a high-resolution HPGe -spectrometer. A statistically significant difference for the concentration of Na and Cl in all tumor samples relative to those in a normal control group is found. During the tumor growing period, concentration of Mg, K, Fe, Se, Rb, Cu, Zn, and Mn in liver and ascites of tumored mice vary with respect to the tumor size. Each elemental concentration and its biological function in the tumored mice is discussed and possible correlation to humans is analyzed.

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Abstract  

Sixteen minor and trace element contents of diet samples collected from the Pratas islanders were determined using instrumental neutron activation analysis. Samples were prepared by the duplicate portion technique, collecting during a 3-day period in winter. Dry weight elemental concentrations and daily dietary intake by islanders are compared with those taken by urban population living in Taiwan, resulting in higher intake of most elements. In addition, concentration of natural radionuclides and artificial fallout in daily diet were determined by means of -spectroscopy; the annual intake of radioactivity was evaluated and compared with those in population of neighboring Taiwan and South China. Features of the elemental concentration and radioactive concentration in the diet are discussed.

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Abstract  

Rapid, in situ measurements were used for quantitative monitoring of gaseous fission products around the nuclear power stations in Taiwan. A portable high-resolution germanium detector with portable multichannel analyzer was used in the field monitoring work. The detecting unit was calibrated using activated Ar, Kr, and Xe isotopes dispersed in a large chamber to obtain absolute efficiency curve in terms of γ-counts per m3 versus gamma-ray energy. The calibrated detecting unit was brought to the nuclear power plants for in situ monitoring for both normal operation and nuclear accidental exercise. In a typical four-hour measurement, the detection limits for most Kr and Xe fission product isotopes were 0.0028%≈0.98% of the derived air concentration (DAC) imposed by the local authority. The dose rate caused by gaseous radioisotopes released from nuclear power stations and dispersed to the surroundings can be quantitatively monitored in a short period using this portable unit.

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Abstract  

The concentration of radionuclides in environmental samples and the environmental radiation level (including cosmic rays) was monitored on Spratly Islets in South China Sea prior to the commercial operation of nearby Chinese nuclear power plants. Samples of coral sand, sea food, vegetation, water, and accumulated fallout on the islet were obtained and measured for radioactivity. Except for some exposure originating from minute amounts of60Co and137Cs, the radiation background is mainly emitted from naturally occurring radionuclides. Radiation levels including beta, gamma, and neutron on the islet have also monitored. Gamma dose rates for outdoor exposure averaged approximately 0.09 Sv/h; the neutron dose rate was about 0.003 Sv/h. Automatic radiation surveillance and a routine sampling program on the Spratly Islets are viewed as essential to provide an early warning in the Far East in case of a nuclear emergency.

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Abstract  

The radionuclide concentration in environmental samples and radiation level on Pratas Island are measured prior to the commercial operation of Da-Ya Bay Nuclear Power Plant nearby. Except for some minute amount of60Co and157Cs, radiation background is mainly from naturally occurring radionuclides. Automatic radiation surveillance and a routine sampling program on Pratas Island are essential to provide early warning for Taiwan in case of nuclear emergency.

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