[en] We investigate the high temperature thermodynamical chemistry behaviors of the spinel compounds concerning the radiation field formation. The characteristics of cation distribution in the spinel lattice was estimated by thermodynamic calculation. The non-stoichiometry and the change of free energy of single and mixed spinel compounds containing Fe²⁺, Ni²⁺, Co²⁺ and Zn²⁺ were calculated and evaluated. It appeared that the ferrites containing iron, nickel or cobalt had inverse spinel structures, while that containing zinc had a normal spinel structure. Each calculated value of the chemical compositions, x and y, in a binary or ternary mixed spinel system, A²⁺_xB²⁺_yFe³⁺_1-x-y(A²⁺_k-xB²⁺_1-k-yFe³⁺_1+x+y)O₂= (the k is initial mole fraction), in which A or B is Fe²⁺, Ni²⁺, Co²⁺ or Zn²⁺, was shown to be compound-dependent. The whole free energy changes of site transfer and formation appeared to be thermodynamically well mixed when k was 0.5 and when the temperature was higher. In addition, Nickel ferrite was synthesized by co-precipitation method and identified, and a chemical system for solution pH controlling and co-precipitate washing were selected

[en] With thermodynamic spinel models, the cation distribution and free energy change dependent on temperature was calculated. For the spinel containing Co, Zn, Fe or Ni at 250 .deg. C, the calculated results showed the composition of Co_0.15Fe_0.85[Co_0.85Fe_1.15]O₄, and Zn_0.75Fe_0.25[Zn_0.25Fe_1.75]O₄. FeFe₂O₄ or NiFe₂O₄ was shown to have almost complete inverse spinel composition. The mixing of Fe-contained ferrite and Co-contained one gave the composition of Fe₂+0.479Co₂+0.00075Fe₃+0.520[Fe₂+0.021Co₂+0.499Fe₃+1.479]O₄ at 250 .deg. C. Ni_0.75Fe_2.25O₄ was synthesized by co-precipitation and identified with XRD, SEM, XPS and EDX. When potassium carbonate and secondary distilled water were used as solution pH controlling agent and co-precipitate washing agent, respectively, the final composition ratio of Ni and Fe in the ferrite appeared to be almost identical to the initial one. These results would be based on modelling of mixed spinel chemistry, deduction of calculation equations and synthesis of 3-component spinels

[en] Experiments on aqueous TiO₂ photo catalytic reaction of nitrogen containing organic compounds such as ethylamine, phenylhydrazine, pyridine, urea and EDTA were carried out. Based on the values calculated for the distribution of ionic species and atomic charge, the characteristics of their photo catalytic decomposition were estimated. It was shown that the decomposition characteristics was linearly proportional to nitrogen atomic charge value. On the other hand, the effects of aqueous pH, oxygen content and concentration on the TiO₂ photo catalytic characteristics of EDTA, EDTA-Cu(II) and EDTA-Fe(III) were experimentally investigated. All EDTA systems were decomposed better in the pH range of 2.5-3.0 and with more dissolved oxygen. These results could be applied to construction of a process for removal of organic impurities dissolved in a source of system water, or for treatment of EDTA-containing liquid waste produced by a chemical cleaning in the domestic NPPs. (author)

[en] The research area deals with the reliable determination of the hard-to-measure radionuclides(RNs) in environmental samples, and an improved understanding of the role of humic substances for the radionuclides transport in the geosphere. The research subjects are as follows; 1. Development of determination of the hard-to-measure RNs 2. Development of portable scintillation counter system for the field measurement 3. Development of analysis techniques of radionuclides using ICP-MS 4. The understanding of the role of humic substances on the transport of radionuclides

[en] For more realistic assessment of Korean food chain radiation doses due to the operation of nuclear facilities, it is required to use domestically produced data for radionuclide transfer parameters in crop plants. In this report, results of last about 15 years' studies on radionuclide transfer parameters in major crop plants by the Korea Atomic Energy Research Institute, were summarized and put together. Soil-to-plant transfer factors, parameters quantifying the root uptake of radionuclides, were measured through greenhouse experiments and field studies. In addition to traditional transfer factors, which are based on the activity in unit weight of soil, those based on the activity applied to unit area of soil surface were also investigated. Interception factors, translocation factors and weathering half lives, parameters in relation to direct plant contamination, were investigated through greenhouse experiments. The levels of initial plant contamination with HTO and I2 vapor were described with absorption factors. Especially for HTO vapor, 3H levels in crop plants at harvest were expressed with TFWT (tissue free water tritium) reduction factors and OBT (organically bound tritium) production factors. The above-mentioned parameters generally showed great variations with soils, crops and radionuclide species and application times. On the basis of summarized results, the points to be amended or improved in food chain dose assessment models were discussed both for normal operation and for accidental release

[en] For the materials science by neutron technique, the development of the various complementary neutron beam facilities at horizontal beam port of HANARO and the techniques for measurement and analysis have been performed. Small angle neutron spectrometer, after the installation and the performance test, has been opened and used actively for polymer study, nano-size irregularities study, etc., since July 2001. In the development of neutron reflectometer, reinforcement work of ST3 horizontal beam port floor, fabrication and installation for ST3 shield have been carried out. Also, it's characteristics such as thermal neutron flux, dosimetry of shield surface were evaluated. For the installation of polarized neutron spectrometer, monochromator drum was supplemented, and mechanical driving system was fabricated and installed. And, spin flipper and magnet guide field were developed. The various sample environmental facilities for low temperature, high temperature and magnetic field were developed successfully. Therefore, materials study using neutron spectrometer under versatile sample environmental condition could be performed. In order to enhance neutron spectroscopy technique, evaluation of hydrogen content in metal, magnetic structure analysis, accurate measurement and analysis of hydrogen position have been done. The micelle structure analysis, formation study of texture and precipitate in IF steel, residual stress analysis were also done. The main part of neutron spectrometer such as neutron monochromator, 1-D, 2-D position sensitive detector and step motor controller for high current were developed. The development of real time neutron radiography and tomography technique using CCD and SIT camera were carried out. Therefore, initial moving image of ASTM, BPI, SI and 3-D tomography image of automobile evaporator, turbine blade were measured. Also, the measurement technique of boron distribution in iron, Si wafer using micro radiography was developed

[en] Experiments on aqueous TiO² photocatalytic reaction characteristics of 4 nitrogen-containing and 12 aromatic organic compounds were carried out. Based on the values calculated for the distribution of ionic species and atomic charge, the characteristics of their photocatalytic decomposition were estimated. It was shown that the dependence of decomposition of the N-containing compounds were linearly proportional to their nitrogen atomic charge values, while that of the aromatic compounds were inversely proportional. The effects of aqueous pH, oxygen content and concentration on the TiO² photocatalytic characteristics of EDTA-Cu(II) and EDTA-Fe(III) were experimentally investigated. All EDTA systems were decomposed better in the pH range of 2.5∼3.0 and with more dissolved oxygen. These results could be applied to a unit process for removal of organic impurities dissolved in a source water of the system water, and for treatment of EDTA-containing liquid waste produced by chemical cleaning process in the domestic NPPs

[en] In an experiment on TiO₂ photo-catalysis of five nitrogen-containing organic compounds, the changes of pH and total carbon contents were measured, and the dependence of their photo-catalytic characteristic upon their chemical structures were investigated. -- calculation of the effect of ionic carbon species in an aqueous solution on thermodynamic equilibrium, pH and conductivity showed a small quantity of organics could lead conductivity increase and pH reduction. -- Based on the results of photo-catalytic experiment of ethylamine, phenylhydrazine, pyridine, urea or EDTA, irradiated for 180 minutes after adsorption onto titanium dioxide for 60 minutes, relationship between nitrogen atomic charge and the first-order rate constant was as the following: R (1st - order rate constant) = δ (ε - a )^1/3 + b where, ε : atomic charge of nitrogen in a molecular, δ, a and b : corrective coefficients

[en] Simple abdomen film has played an important role in decision of emergency operations in patients with the abdominal trauma. Nowadays, it still acts as a primary and inevitable processes in emergency condition. At the Department of Radiology, Hanil Hospital, 70 patients, who were laparotomied due to penetrating or nonpernetraing abdominal trauma, were observed and analyzed with simple abdomen film after comparison with the operative findings. The results are as follows: 1. Most frequent age distribution was 10 to 39 years and marked 70%. Male was in 90% incidence. 2. Penetrating injury largely involved the small bowel and abdominal wall. Non-penetrating injury usually involved the spleen, small bowel, liver, kidney, pancreas, duodenum. 3. Single organ injury occurred in higher incidence at the small bowel and abdominal wall. Multiple organ injury occurred in higher incidence at the spleen, liver, kidney and pancreas. 4. Organ distribution was 26% in spleen, 22% in small bowel, 14% in liver, 11% in abdominal wall. 7% in pancreas, 7% in kidney. 5% in duodenum, 4% in GB and CBD, 2% in diaphragm, 2% in colon, and 1% in stomach. 5. The specific roentgen findings and their frequency which useful in differential diagnosis at abdominal trauma, were as follows: a) flank fluid; Detectable possibility was 71% in liver laceration, 69% in spleen laceration and 57% in pancreas laceration. b) ipsilateral psoas shadow obliteration; Detectable possibility was 57% in liver laceration, 57% in kidney laceration and 46% in spleen laceration. c) free air; Detactable possibility was 60% in duodenal perforation, and 36% in peroration of upper part of small bowel. d) Reflex ileus; Detectable possibility was 64% in small bowel, 50% in liver laceration and 35% in spleen laceration. e) rib fracture; Detactable possibility was 36% in liver laceration and 23% in spleen laceration. f) pleural effusion; Detectable possibility was 29% in liver laceration and 27% in spleen laceration

[en] Since ammonia, for pH control in order to minimize corrosion product in domestic PWR secondary system, is very volatile, tends to stay with steam phase, resulting in not providing proper pHs, advanced amine application is required. On the other hand, dissolved organics in the system water should be removed during purification, since they have a negative effect on cycle pH. Therefore, the characteristics of pH control agent with ammonia, morpholine, AMP, ETA and MPA were evaluated, and the effect of dissolved organics on pH and the characteristics of photocatalysis for removal of them were studied. Based on the base strength, distribution coefficient and thermal decomposition rate of them, a single amine system of MPA seems to be available. Under consideration of wet stream area protection and low temperature feedwater pH requirement, a mixed amine system of ETA with MPA or morpholines thought to be more available. The calculated values of thermodynamic equilibrium between carbonic acid, carbonate, bicarbonate and carbon dioxide agreed with the values measured from photocatalytic decomposition experiments of salicylic acid. It showed that the conductivities of the aqueous solution decreased, while pH increased even with extremely small quantities of organic acids. While, results experimentally obtained from photocatalytic decomposition of the amines above showed photocatalysis would be an available process for removal of dissolved organics. (author). 35 refs., 11 tabs., 34 figs