[en] Glass surface tension and CCM test conditions were investigated for swelling generation cause of radioactive wastes vitrification process. The surface tension variation due to raw glass, additives, waste chemical composition were investigated, and such mineral composition as Li₂O, al₂O₃, CaO, Fe₂O₃ increased the glass surface tension. In addition, waste feed rate, bubbling flow rate, CCM inner pressure for CCM test conditions were investigated, and waste feed rate, total feed amount have an effect on swelling. Therefore, according to mineral composition of raw glass, additives and waste feed rate and total feed amount would be controlled to prevention swelling

[en] The high temperature melting test for nonflammable wastes using a plasma torch was conducted. The AP-200L hollow cathode type plasma torch was installed at the pilot plasma melting furnace in NETEC. The surrogates were prepared to simulate concretes, soil and their mixture with steel. The experimental conditions such as feeding rate, the distance between melts surface and torch nozzle, torch rotation speed, gas flow rate and pressure in the furnace were decided. Basic parameters such as temperatures of cooling waters, off-gas and torch power were measured. The vitrified samples were analyzed by SEM/EDS

[en] We have described an electromagnetic field confined in a cubic cavity filled with a conductive medium from the viewpoint of quantum mechanics; we have also described the field propagating under periodic boundary conditions, and the field having continuous modes, from the viewpoint of quantum mechanics. The amplitudes of both the electric and magnetic fields decrease exponentially with time due to the conductivity of the medium. This result exactly coincides with a classical electrodynamic analysis

[en] Nuclear Environment Technology Institute (NETEC) has investigated and evaluated various efficient thermal treatment technologies for the LILW generated from NPPs. NETEC has especially focused on a treatment technology for the LILW to have a large volume reduction effect which abates the rapid increase in saturation of on-site storage capacity and disposal costs, to enhance the stability of the waste form, and to treat all waste streams generated from Korean NPPs. Vitrification technology to treat the LILW was concluded as the most promising technology because it can achieve large waste volume reduction, create a durable waste form and decompose organic compounds more effectively than other competing technologies such as cementation, polymerization, and ceramic formation. The vitrified radioactive waste is expected to remain stable in the repository environment more than one million years because this technology is to chemically incorporate the radionuclides in the LILW into the durable glass matrix. Therefore, the safety of the repository can be greatly enhanced. In addition, vitrification technology contributes to remarkable waste volume reduction factor of greater than 20 compared to the initial bulk volume of the waste and results in efficient and prolonged utilization of the disposal site in Korea

[en] By using a batch type plasma torch melting system, continuous feeding and melting tests of non-combustible waste were executed. Using the results, the establishment of a heat transfer model and its verification were executed; the characteristics of the molten slag, exhaust gas, fly dust, volatilization of Cs, and leaching of slag were analyzed. In order to establish the heat transfer mode, the followings were considered; the electrical energy supplied to the plasma torch, the absorbed energy to the plasma torch for generating the plasma gas, the absorbed energy to the cooling water of the plasma torch, the energy supplied to the melter from the plasma gas by radiant heat, the energy loss through the exhaust gas, the waste melting energy, and the heating energy of an inner crucible and the melter. The concrete and soil were melted for the verification of the model. The waste was fed through waste feeder by the amount of 0.5kg or 1kg that was calculated by using the model. The experiment for the verification resulted in that the model was fitted well until the melter was heated sufficiently. If the electrical energy of 128kW were supplied to the plasma torch, energy balance of the plasma melting system was calculated with the model: the absorbed energy to the plasma torch for generating the plasma gas (27kW), the absorbed energy to the cooling water of the plasma torch (0∼ 36kW), the energy loss through the exhaust gas (5 ∼ 8kW), the waste melting energy (14kW), and the heating energy of an inner crucible and the melter (82 ∼ 43kW)

[en] Since the first Korean nuclear power plant (NPP), Kori 1, commenced operation in 1978, a total of 21 NPPs had been put into operation in Korea by the end of 2011. Radiation doses of NPP workers have been periodically evaluated and controlled within the prescribed dose limit. Radiation dose assessment is carried out monthly by reading personal dosemeters for external radiation exposure, which have traceability in compliance with strict technical guidelines. In the case of the internal radiation exposure, workers who have access to the possible area of polluted air are also evaluated for their internal dose after maintenance task. In this article, the overall situation and experience for the assessment and distribution of radiation doses in Korean NPPs is described. (authors)

[en] In order to vitrify the W1 waste (ion-exchange resin(IER), zeolite, and dry active waste(DAW)) generated from Korean Nuclear Power Plants, a glass formulation development based on waste compositions and production rates was performed. A aluminoborosilicate glass, AG8W1, was formulated to vitrify the W1 waste in an induction cold crucible melter(CCM). The processability, product performance, and economics of the candidate glass were calculated using a computer code and were measured experimentally in the laboratory and CCM. The glass viscosity and electrical conductivity as the process parameters were in the desired ranges. Start-up and maintaining glass melt of the candidate glass were favorable in the CCM. The product quality of the glass such as chemical durability, phase stability, etc. was satisfactory. The vitrification process using the candidate glass was also evaluated to be operated as economically as possible

[en] In order to vitrify the combustible dry active waste (DAW) generated from Korean Nuclear Power Plants, a glass formulation development based on waste composition was performed. A borosilicate glass, DG-2, was formulated to vitrify the DAW in an induction cold crucible melter (CCM). The processability, product performance, and economics of the candidate glass were evaluated using a computer code and were measured experimentally in the laboratory and CCM. The glass viscosity and electrical conductivity as the process parameters were in the desired ranges. Start-up and maintaining glass melt of the candidate glass were favorable in the CCM. The product quality of the glass such as chemical durability, phase stability, etc. was satisfactory. The vitrification process using the candidate glass was also evaluated to be operated as economically as possible

[en] Using the dynamical invariant operator method, we obtain the exact wave function, uncertainty relation, and energy eigenvalues for the harmonic oscillator with the classical equation of motion in the form of Mathieu functions. The probability density varies as a function of position, but is almost constant in time. The uncertainty relations satisfy the minimum uncertainty, and the energy eigenvalues oscillate slowly or rapidly depending on the frequency. The quantum and classical energies oscillate in a similar fashion with respect to frequency and time

[en] The exact wave function, energy eigenvalues and uncertainty relations of a lengthening pendulum are evaluated explicitly through the use of a time-dependent dynamical invariant method. The energy eigenvalues decrease linearly as time goes by, and the minimum value of the uncertainty is larger than h/2