Rapid monitoring of gaseous fission products released from nuclear power stations

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.     

Environmental radiation detected at Lin Shin hospital in Taichung during the Fukushima nuclear power plant accident

This work is the first evaluation of environmental gamma exposure rates by the Nuclear Medicine Department at Lin Shin Hospital (LSH) in Taichung with Thermoluminescent dosimeter (TLD-100H) during the Fukushima Nuclear Power Plant (FNPP) accident. After the 9.0 M_W strong earthquake hit northern Japan on March 11, 2011, a TLD-100H was used to monitor environmental kerma rate at Taichung (2,500 km away from northern Japan) from Mar-08 to Apr-09, 2011 and evaluated kerma rate due to global fallout of the sever FNPP accidents. Exposure rates varied widely among positions close to the PET/CT facility. Observed kerma rates of up to 4.12 ± 0.62 mSv mo⁻¹ indicated an explicit, heavy leakage of photon through the PET/CT facility. No significant contributions were detected at Taichung, Taiwan. Hence, the health effect cause by the “extra radiation” from FNPP accidents is negligible. As this was a rare case of environmental monitoring during a nuclear power plant accident, its findings are of considerable significance.     

Quantification of <Superscript>241</Superscript>Pu in aerosols released from nuclear power plants

Two peptide ligands conjugated adenine, [9-N-(tritylmercapto acetyl diglycyl aminoethyl) adenine, Tr-MAG₂-Ade] and [9-N-(tritylmercapto acetyl triglycyl aminoethyl) adenine, Tr-MAG₃-Ade], are synthesized and labeled with ^99mTc by directly labeling method. The stability of ^99mTc-MAG₂-adenine and ^99mTc-MAG₃-adenine in vitro is measured. The uptake radios of tumor to muscle at 3h post-injection are 5.70 and 4.92, respectively. The biodistribution and scintigraphic imaging studies show that the two complexes have high localization in tumor and high contrasted tumor images can be obtained, which suggest their potential utility as tumor imaging agents. But the high radioactivity of abdomen could prevent the tumor imaging in this area.     

Automated separation and analysis of krypton-85 from low-volume gaseous effluent of nuclear power plant

Journal of Radioanalytical and Nuclear Chemistry - Based on the requirements of the lower detection limit for the low-volume gaseous effluent, we have designed an automatic separation apparatus of...     

Determination of soft X-ray emitting isotopes in radioactive liquid wastes of nuclear power plants

The ⁵⁹Ni and ⁵⁵Fe radioisotopes were measured in radioactive wastes of some European nuclear power plants. A sample preparation method was developed that starts with the digestion in an oxygen atmosphere at an overpressure in a closed Berthelot calorimeter bomb. The detection limits for ⁵⁹Ni and ⁵⁵Fe were measured and calculated in the presence of high background activities from ⁶⁰Co, ¹³⁷Cs and ²⁴¹Am isotopes.     

Management of carbon dioxide released from spent nuclear fuel through voloxidation

Journal of Radioanalytical and Nuclear Chemistry - The management of radioactive carbon (C-14) from spent nuclear fuel (SNF) in a voloxidation process is vital to prevent radioactive contamination...     

Measurements of actinide nuclides in water samples from the primary circuit of a nuclear power plant

Weekly, consecutive primary coolant samples from a boiling water reactor have been analyzed for^{239, 240}Pu,²³⁸Pu+²⁴¹Am,²⁴²Cm and²⁴⁴Cm for about two years, and for²³⁸Pu,²⁴¹Pu and²⁴¹Am for one year. Concentration ranges are reported. Samples were prepared for counting either directly by evaporation or by chemical separation on BioRad AG 1×4 resin and subsequent electrolysis, and were counted in 20 cm dia Frish grid ionization chambers. Procedures are described. For most actinide nuclides, activity ratios in primary coolant were found to be different from those in worldwide fallout, thus allowing an identification of origin in the case, that actinides should be detected in the vicinity of a nuclear power station.     

Separation of63Ni traces from low and medium level radioactive wastes produced during the operation of nuclear power reactors

The classification of low and medium level radioactive wastes produced regularly by nuclear power plants is becoming ever more important in Mexico, after a few years of running the first of two units, 600 MeV each, in Laguna Verde nuclear power plant. This paper describes a method to separate and detect traces of the weak -emitter⁶³Ni, which is one of the activation products used to classify low and medium level radioactive wastes originating from the operation of nuclear power plants.     

Removal of nickel from water and synthetic nuclear power plant coolant water by ion exchange resins

A method for the removal of nickel from waste water by adsorption process on ion exchange resin was studied. The percentage removal of nickel depends upon the contact time, pH and dose of adsorbent. Adsorption of nickel on ion exchange resins obeys Freundlich adsorption isotherm. The applicability of Lagergren kinetic model has also been investigated. In order to understand the adsorption behavior of nickel, a number of batch experiments were conducted at various pH values. The results show that the adsorption is maximum in the pH range 2 to 8. The studies showed that the ion exchange resins IRN77 and SKN1 can be used as an efficient adsorbent material for the removal of Ni(II) from water and coolant water.     

Pilot determinations of 3H and 14C in gaseous releases from Kozloduy nuclear power plant

Methods for routine assessment of ³H and ¹⁴C content in gaseous releases from ventilation stacks of Kozloduy Nuclear Power Plant (Bulgaria) were developed. Technique for correction of incomplete desorption of tritium from exposed silica gel was proposed. The distribution and the concentrations of both nuclides in various chemical forms were constantly monitored for a period of 1 year. The results for annual normalized gaseous discharges were assessed for the fifth unit at 173 GBq/(GW.a) for ³H and 369 GBq/(GW.a) for ¹⁴C, while for the sixth unit—³H—98 GBq/(GW.a) and ¹⁴C—289 GBq/(GW.a).     

Application of micellar electrokinetic chromatography for detection of silver nanoparticles released from wound dressing

The recent emergence of nanotechnology has provided a new therapeutic modality in case of silver nanoparticles. Dressings containing silver form the basis for the treatment of burns and wounds, either acute or chronic ones. The aim of the study was to examine silver release from the different wound dressings: commercially available (Atrauman Ag, Aquacel Ag) and experimental (FKDP‐AgNPs) using MEKC. In order to characterize prepared keratin based wound dressing before and after its modification with AgNPs, a compositional analysis was conducted using energy dispersive X‐ray spectroscopy. Nanosilver toxicity was evaluated with the 3‐(4,5‐dimethylthiazol‐2‐yl)‐5‐(3‐carboxymethoxyphenyl)‐2‐(4 sulfophenyl)‐2H‐tetrazolium test. Silver release from wound dressings was assessed using MEKC. The best separation was observed for MEKC in 20 mM borate buffer at pH 9 with 20 mM SDS addition. In vitro studies showed silver at higher concentration than 10 ppm exerted a toxic effect on fibroblasts isolated from diabetic mice versus. NIH/3T3 and BJ cell lines (p < 0.05). We observed silver was released more gradually from experimental FKDP‐AgNPs wound dressing, in compare to commercially available wound dressings. The fast and low‐cost method utilizing MEKC can be used in clinical practice to detect silver release from the wound dressings.     

Adsorption characteristics of carbon on ion exchange resin in nuclear power plant

The adsorption characteristics of carbon on a strong base anion and cation exchange mixed resin, Amberlite IRN-150 in OH⁺ and H⁻ (1∶1) used in nuclear power plant, were investigated at 6, 30 and 50 °C at a concentration of carbon up to 0.02M. The expression for the adsorption of carbon was well fitted to the Freundlich equation and the constants,k andn in the equation were deduced. Furthermore, we could explain that the adsorption capacity on the mixed resin increases with temperature.     

Improved method for the determination of manganese in nuclear power plant waters

An improved method for manganese determination in nuclear power plant waters has been developed. This method combines a selective chelation concentration method with a unique analytical separation for manganese from the interfering matrix using a weak acid cation exchange column. The detection sensitivity by conventional post-column derivatization is improved with the combination of chemical eluent suppression and subsequent post-column derivatization. The detection limit for manganese in ammonium matrix is approximately 2 pg/ml and the limit of quantitation 10 pg/ml with 100 ml sample volume.     

Decomposition of 14C containing organic molecules released from radioactive waste by gamma-radiolysis under repository conditions

Decomposition of ¹⁴C containing organic molecules into an inorganic compound has been investigated by γ-ray irradiation experiments under simulated repository conditions for radioactive waste. Lower molecular weight organic acids, alcohols, and aldehydes leached from metallic waste are reacted with OH radicals to give carbonic acid. A decomposition efficiency that expresses consumption of OH radicals by decomposition reaction of organic molecules is proposed. Decomposition efficiency increases with increasing concentration of organic molecules (1×10⁻⁶–1×10⁻³ mol dm⁻³) and is not dependent on dose rate (10–1000 Gy h⁻¹). Observed dependence indicates that decomposition efficiency is determined by reaction probability of OH radicals with organic molecules.     

A study on the clearance of metal frames of waste filters from ventilation system in nuclear power plant

Journal of Radioanalytical and Nuclear Chemistry - The ventilation filters from ventilation system in the control area of nuclear power plant will be regularly replaced. In general, the metal frame...     

Research with radiation and radioisotopes to better understand plant physiology and agricultural consequences of radioactive contamination from the Fukushima Daiichi nuclear accident

Research carried out by me and my group over the last almost four decades are summarized here. The main emphasis of my work was and continues to be on plant physiology using radiation and radioisotopes. Plants live on water and inorganic elements. In the case of water, we developed neutron imaging methods and produced ¹⁵O-labeled water (half-life 2 min) and applied them to understand water circulation pattern in the plant. In the case of elements, we developed neutron activation analysis methods to analyze a large number of plant tissues to follow element specific distribution. Then, we developed real-time imaging system using conventional radioisotopes for the macroscopic and microscopic observation of element movement. After the accident in Fukushima Daiichi nuclear power plant, we, the academic staff of Graduate School, have been studying agricultural effects of radioactive fallout; the main results are summarized in two books published by Springer.