Untreated waste is temporarily stored on the site of the nuclear power plant. In some nuclear power plants, saturation period of temporary storage waste is less than 10 years away. As untreated waste continues to be generated in nuclear power plants, it could also affect management of operations. Accordingly, CRI is developing the 3.5 generation plasma torch melting facility for waste treatment. The 3.5th generation plasma torch melting facility consists of melter, plasma torch, waste supply device, exhaust gas treatment facility, power supply, etc. Melter is composed of melting chamber for melting control and pyrolysis chamber for waste pretreatment, and dam-type discharge device is adopted to overflow the melt. Plasma torch is hollow type with reversed discharge, has a rating of megawatt class, and has two gas supply lines. It can be used in transfer mode, non-transfer mode and mixed mode. There are three types of device for waste supply. The first is a drum pusher for injecting 200 L drums, the second is a screw-type waste supply and hopper for injecting solid waste, and the third is a nozzle-type waste supply device for injecting liquid waste. Exhaust gas treatment facility was equipped with post combustion chamber, off-gas cooler, high-temperature filter, HEPA filter, reheater, scrubber, ID fan and etc. Power supply of plasma torch operation is designed with a capacity of 1.5 megawatt (Maximum) and consists of channels A and B. Transfer mode, non-transfer mode and mixing mode of plasma torch may be selected through the control of PLC. This paper introduces the composition and function of the 3.5th generation plasma torch melting facility of CRI. In order to solve the problems arising through the operation of the 3rd generation plasma torch melting facility, an optimization plan is applied.

The liquid radioactive waste system of nuclear power plants treats radioactive contaminated wastes generated during the Anticipated Operational Occurrence (AOO) and normal operation using filters, ion exchange resins, centrifuges, etc. When the contaminated waste liquid is transferred to an ion exchanger filled with cation exchange resin and anion exchange resin, nuclides such as Co and Cs are removed and purified. The lifespan and replacement time of the ion exchange resin are determined by performing a performance test on the sample collected from the rear end of the ion exchanger, and waste ion exchange resin is periodically generated in nuclear power plants. In the general industry, most waste resins at the end of their lifespan are incinerated in accordance with related laws, but waste resins generated from nuclear power plants are disposed of by clearance or stored in a HIC (High Integrity Container). Plasma torch melting technology can reduce the volume of waste by using high-temperature heat (about 1,600 degrees) generated from the torch due to an electric arc phenomenon such as lightning, and secure stability suitable for disposal. Plasma torch melting technology will be used to check thermal decomposition, melting, exhaust gas characteristics, and volume reduction at high temperatures, and to ensure disposal safety. Through this research, it is expected that the stable treatment and disposal of waste resins generated from nuclear power plants will be possible.

Filtering nuclides in high-level nuclear waste using rotating plasmas is a physical separation method based on mass difference. Since it is not chemical separation or metallurgical separation, the elements are separated regardless of their chemical composition. Accordingly, the more the number of chemical elements present in the waste or the more difficult when using the differences in solubility, the more advantageous. However, to be economically competitive, new concepts for rotating plasmas are needed to improve the poor separation rates despite high energy and installation costs. In this work, we revisited a counter rotating plasma centrifuge to examine its potential as an effective device for separating nuclear waste efficiently and economically.

This study investigated the influence of sodium bicarbonate (NaHCO3) and progesterone on acrosome reaction and proportion of polyunsaturated fatty acid (PUFA) composition boar sperm. The sperm were diluted with semen extender and incubated with NaHCO3 and progesterone at 38℃, 5% CO2 for 6 h. Plasma membrane integrity and acrosome reaction were analyzed using SYBR14/propidium iodide (PI) and FITC-PNA/PI doubling staining method, and proportion of PUFA was analyzed using gas chromatography. In results, Plasma membrane integrity was significantly decreased in 50 mM NaHCO3 group and acrosome reaction was significantly increased by over the 100 mM NaHCO3 group compared to control group (p < 0.05). In addition, progesterone significantly increased decreased plasma membrane integrity at 100 mM progesterone and acrosome reaction at over the 5.0 µM progesterone (p < 0.05), but there was no difference among the 5.0 to 100 µM groups. PUFAs were significantly decreased in 100 mM NaHCO3 and 50 µM progesterone treatments compared to control group. In summary NaHCO3 and progesterone induce acrosome reaction and reduce PUFA composition in boar sperm, therefore, the results maybe help to understand basically knowledge for the acrosome reaction and PUFA composition in boar sperm.

Pregnancy-associated plasma protein-A (PAPP-A) is known as an important biomarker for fetal abnormality during first trimester and has a pivotal role in follicle development and corpus luteum formation. And also, it is being revealed that an expression of PAPP-A in various cells and tissues such as cancer and lesion area. PAPP-A is the major IGF binding protein-4 (IGFBP-4) protease. Cleavage of IGFBP-4 results in loss of binding affinity for IGF, causing increased IGF bioavailability for proliferation, survival, and migration. Additionally, PAPP-A can be used as a promising therapeutic target for healthy longevity. Despite growing interest, almost nothing is known about how PAPP-A expression is regulated in any tissue. This review will focus on what is currently known about the zinc metalloproteinase, PAPP-A, and its role in cells and tissues. PAPP-A is expressed in proliferating cells such as fetus in uterus, granulosa cells in follicle, dermis in wound, cancer cells, and Sertoli cells in testis. They have common characteristics of proliferation faster than normal cells with stimulating IGFs action and inhibiting IGFBPs. The PAPP-A functions and expression studies in livestock have not yet been conducted much. Further studies are needed to use PAPP-A as a marker for healthy longevity in animal science.

This study aims to establish a modified analytical method with sensitivity and reliability for streptomycin (STP) and dihydrostreptomycin (DHS) of residues level in pig tissues, plasma and urine by LC-MS/MS on the basis of previous studies. The mass parameters of quantitative and qualitative ions for STP and DHS were optimized using multiple reaction monitoring in positive mode. The separation of compounds was conducted using BEH Amide column according to material’s characteristics. The analytes in plasma were extracted with only organic solvents. In muscle and kidney, KH2PO4 buffer solution containing 2% CCl3COOH and EDTA-Na was used as extraction solvent. The WCX cartridege was selected as SPE cartridge in considering high recoveries for STP and DHS. The analytes in urine were extracted by organic solvents with acid and addition of EDTA. The limits of detection (LODs) in STP and DHS ranged 0.45~3.66 μg/kg and 0.22~0.78 μg/kg, respectively. The limits of quantification (LOQs) were 1.35~11.10 μg/kg in STP and 0.66~2.36 μg/kg in DHS. The recoveries (%) were 94.29~104.5% in STP and 92.32~108.45% in DHS except for plasma with lower values (61.45/68.5%, respectively). In the precision evaluation, the coefficient of variation (CV, %) of STP showed <10.50% on intra-day and <18.04% on inter-day. The CV (%) of DHS showed <8.42% on intra-day, whereas <17.98% on inter-day. The modified method is reliable for continuous residual monitoring in pig to ensure food safety for consumer’s health. In addition, this method could be used in study relation to residue depletion and pharmacokinetics of veterinary drug.

An alternative fabrication method for carburizing steel using spark plasma sintering (SPS) is investigated. The sintered carburized sample, which exhibits surface modification effects such as carburizing, sintered Fe, and sintered Fe–0.8 wt.%C alloys, is fabricated using SPS. X-ray diffraction and micro Vickers tests are employed to confirm the phase and properties. Finite element analysis is performed to evaluate the change in hardness and analyze the carbon content and residual stress of the carburized sample. The change in the hardness of the carburized sample has the same tendency to predict hardness. The difference in hardness between the carburized sample and the predicted value is also discussed. The carburized sample exhibits a compressive residual stress at the surface. These results indicate that the carburized sample experiences a surface modification effect without carburization. Field emission scanning electron microscopy is employed to verify the change in phase. A novel fabrication method for altering the carburization is successfully proposed. We expect this fabrication method to solve the problems associated with carburization.

This study investigates the interfacial reaction between powder-metallurgy high-entropy alloys (HEAs) and cast aluminum. HEA pellets are produced by the spark plasma sintering of Al0.5CoCrCu0.5FeNi HEA powder. These sintered pellets are then placed in molten Al, and the phases formed at the interface between the HEA pellets and cast Al are analyzed. First, Kirkendall voids are observed due to the difference in the diffusion rates between the liquid Al and solid HEA phases. In addition, although Co, Fe, and Ni atoms, which have low mixing enthalpies with Al, diffuse toward Al, Cu atoms, which have a high mixing enthalpy with Al, tend to form Al–Cu intermetallic compounds. These results provide guidelines for designing Al matrix composites containing high-entropy phases.

Many countries are developing various mechanical cutting technologies to dismantle nuclear facility. However, most of mechanical cutting technologies have a problem like the degradation of tool life due to the Hard-Machining materials. To solve this problem, lab-scale test was performed with a Plasma Assisted Machining (PAM) technology and 25 mm of thickness Inconel 600 plate. Commonly, the strength of metals decreases by exposure at high temperature. And, previous study reported that strength of Inconel 600 is degraded above 500°C. This softening effect was applied to Inconel 600 cutting test. The optimal conditions such as the plasma torch power and the feed rate were determined by this study. As a result, the surface temperature of Inconel 600 was reached up to 500°C under the conditions which is 8.4 kW of plasma torch power and 150–250 mm·min−1 of feed rate. And it was confirmed that the tool life was improved under the conditions. In order to apply PAM for various Hard- Machining materials, it is necessary to investigate the softening temperature of Hard-Machining materials, the plasma torch power and feed rate.

Various cutting technologies are being developed for dismantling nuclear power plants. these technologies are including mechanical and thermal methods. For example, mechanical cutting methods include sawing, drilling and milling. But, due to the strength of material, mechanical cutting methods have limits of cutting depth and tool life. Therefore, this milling machine assisted plasma torch was developed to improve the limits. And this machine has the principle of softening effect caused by the high temperature. In this work, this developed device was evaluated in view of the cutting depth and tool life in cutting process. For this process, a plasma torch was attached to the front of the endmill processing path to heat the Inconel 600. As results, compare to conventional milling, when the plasma torch power is 6.4 kW, the cutting depth was increased by 4 mm at condition (feed rate is 100 mm·min−1, tool diameter is 10 mm, rotating speed is 1,000 rpm). And cutting length increase 2 times from 300 mm to 600 mm at 16 mm of tool diameter.

In this work, we introduce a 100 kW class mobile plasma melting system designed for non-combustible radioactive wastes treatment. To ensure mobility, the designed system consists of two 24-ft commercial containers, each in charge of the plasma utilities and melting process. In the container for plasma utilities, a 100 kW class DC power supply is installed together with a chiller and gas supply system whereas the container for melting process has a transferred type arc melter as well as off-gas treatment system consisting of a heat exchanger, filtrations, scrubber and NOx removal system. As a heat source for a transferred type arc melter, we adopted a hollow electrode plasma torch with reverse polarity discharge structure. Detailed design for a 100 kW class mobile plasma melting system will be presented together with the main specifications of the components. In addition, the basic performance data of the melting system is also presented and discussed.

In KHNP CRI, the 100 kW PTM (plasma torch melting) system was designed for the treatment and disposal technology of various radioactive wastes including the metal, concrete, liquid waste and insulator. The facility consists of melting chamber, thermal decomposition chamber, waste feeding system and off-gas treatment system. In this study, to evaluate the applicability of the PTM system, demonstration test was conducted using the radiation hazmat suit as combustible waste. The plasma melting chamber is pre-heated by 2nd combustion device and plasma torch for 5 hours. The temperature inside the plasma melting chamber is approximately 1,600°C. The combustible waste was put into the melting chamber by the pusher feeding device with the throughput of maximum 50 kg/hour. During the test, the power of plasma torch is 60–96 kW on the transferred mod. It was evaluated in terms of long-term integrity of PTM system on operation according to the waste throughput ratio.

Plasma melting technology has been considered as promising technology for treatment of radioactive wastes. According to the IAEA TECDOC-1527 report (2006), the technology has an advantage that it can treat regardless of waste types which is both combustible and non-combustible wastes. In particular, it is expected that a large amount of concrete, a representative non-combustible wastes, will be generated during the operation and dismantling of nuclear power plants. In order to treat the concrete waste in plasma torch melting system, various factors could be considered like the slag of electric conductivity, viscosity and melting temperature. Above all, as a critical factor, the viscosity of the melt is very important to easily discharge the melt. The viscosity of slag (SiO2-CaO-Al2O3 system) can be lowered by adding a basic oxide such as CaO, Na2O, MgO and MnO. The basic oxides are donors of oxygen ions. These oxides are called notwork breakers, because they destroy the network of SiO2 by reacting with it. In this study, the slag composition of the concrete waste was developed to apply the plasma torch melting. Also, demonstration test was performed with the developed slag composition and 100 kW plasma torch melting system.

Currently, KHNP has 24 operating nuclear power plant units with a toal combined capacity of about 23 GWe and two units are under construction. However, permanent stop of Kori unit 1 nuclear power plant was decided in 2017. Accordingly, interest in how to dispose of waste stored inside a permanently stopped nuclear power plant and waste generated as decommissioning process is increasing. KHNP CRI is conducting research on the advancement of plasma torch melting facilities for waste treatment generated during the plant decommissioning and operation period. Plasma torch melting facility is composed of various equipment such as a melting furnace (Melting chamber, Pyrolsis chamber), a torch, an exhaust system facility, a waste supply device, and other equipment. In demonstration test, concrete waste was put in a 200 L drum to check whether it can be pyrolyzed using a plasma torch melting facility. Reproducibility for waste treatment in the form of a 200 L drum and discharge of molten slag could be confirmed, the amount of concrete waste in 200 L Drum that could be treated according to power of plasma torch was confirmed. This demonstration test confirmed the field applicability and stability of plasma torch melting facility, and improved expectations for long-term operation.

In nuclear power plants, insulation is used to protect equipment and block heat. Insulation materials include asbestos, glass fiber, calcium silicate, etc. Various types and materials are used. This study aims to ensure volume reduction and disposal safety by applying plasma torch melting technology to insulation generated at operating and dismantling nuclear power plants. After the evaluation of characteristics by securing thermal insulation materials or similar materials in use at the operational and dismantling nuclear power plant. It is planned to perform pyrolysis and melting tests using the MW plasma torch melting facility owned by KHNP CRI Before the plasma test, check the thermal decomposition and melting characteristics (fluidity, etc.) of the insulation in a 1,600°C high-temperature furnace. The insulation is stored in a 200 L drum and injected into a plasma facility, and the drum and the insulation are to be pyrolyzed and melted by the high temperature inside the plasma torch melting furnace. Through this test, thermal decomposition and melting of the insulation, solidification/ stabilization method, maximum throughput, and exhaust characteristics are confirmed at a high temperature (1,600°C) of the plasma torch. Through this study, it is expected that the stable treatment and disposal of insulation generated from operating and dismantling nuclear power plants will be possible.

Plasma torch melting technology can pyrolyze and melt waste with high-temperature heat (about 1,600°C) using electric arc phenomena such as lightning. Waste that may be treated in a plasma torch melting facility is injected in solid (combustible, non-combustible) and liquid form depending on facility capacity. The 200 L drum type, screw supply type, and nozzle type liquid injection device are applied to MW plasma facilities, and the push rod type and screw supply type are applied to smallcapacity plasma facilities. In consideration of the characteristics of radioactive waste generated from operating and dismantling nuclear power plants, a waste input device suitable for plasma torch facilities was developed and verified through tests. In the future, facility soundness will be confirmed through long-term performance tests, and stability will be secured through continuous improvement.

Tributyl phosphate (TBP) is a well-known and important compound in the nuclear industry for the nuclear fuel reprocessing, and it is also used in a various field such as plastic industry as antifoaming agent. Untreated organic pollutants in TBP can remain in the soil water and cause serious environmental pollution, thus it should be degraded through environmentally friendly methods. The non-thermal plasma-based advanced oxidation process (AOP) is one of the most widely studied and best developed processes owing to its simple structure and ease of operation. In this study, a plasma-based AOP was stably generated using submerged multi-hole dielectric barrier discharge (DBD) and applied to relatively high concentration of TBP solution. A submerged DBD plasma system was designed to directly interact with water, thereby producing reactive oxygen species (ROS) and functioning as a powerful oxidizer. Additionally, UV, O3, and H2O2 are generated by the developed plasma system without using any other additives to produce OH radicals for degrading organic pollutants; therefore, this system circumvents the use of complex and advanced oxidation processes. The electrical properties and concentrations of the active species were analyzed to establish optimal plasma operating conditions for degrading TBP solution. The results were analyzed by measuring the total organic carbon (TOC) and changes in solution properties. Based on these results, a degradation mechanism of TBP solution is proposed. After 50 min of plasma treatment, the concentration of TOC was gradually decreased. Consequently, we found that plasma-based AOP using submerged multi-hole DBD has advantages as an alternative technology for degrading organic pollutants such as TBP solution.