In the recent era of the fourth industrial revolution, many industries aim to maximize the efficiency of products and services by introducing cutting-edge technologies such as artificial intelligence and big data. In this situation, organizational culture is changing a lot due to the influx of the MZ generation with strong individualistic tendencies and the decreased face-to-face communication between members. However, active communication with colleagues is still essential to maximize performance, and the margins created by simplifying work processes and automating processes must be used for creating work performance. This requires cooperation and commitment through the job immersion of members who have an active attitude. This study analyzed how the organization's autonomous work environment and trust among members, which are creative work performance conditions, affect job immersion using raw data from the Occupational Safety and Health Research Institute. As a result, it was found that both the organization's autonomous working environment and trust among members significantly effected the members' job immersion. in order to achieve productivity and value improvement in companies, efforts are needed to increase workers' job immersion by building an autonomous working environment and trust among members. The results of this study are expected to contribute significantly to the search for ways to increase workers’ job commitment to improve organizational productivity.

본 연구는 신생아 검사 중 포수클로랄(chloral hydrate)을 투여 후 진행되는 신생아 진정 검사 대비 진정 대체 방식 중 하나인 피드 및 랩(feed and wrap) 방식의 유용성을 평가한 연구이다. 본 연구에선 진정으로 진행한 신생아의 두뇌 T2 축면 영상과 피드 및 랩 방식으로 진행한 같은 영상 각 30개의 운동 허상(motion artifact)과 백질과 회백질의 구분 정도를 두 명의 영상의학과 전문의가 정성적으로 평가하였고, 운동 허상을 측정하기 위해서 위상부호화(phase encoding) 방향의 배경 영역(background area)의 평균 신호 강도(mean signal intensity)를 구하여서 정량적 방식으로 평가하였다. 또한 총검사 시간을 정리한 뒤 정량적 방식으로 평가하였고 투약 기록의 여부와 간호일지를 토대로 피드 및 랩 방식의 총 39건의 검사 건수 대비 성공률을 측정하였다. 운동 허상의 정량적 평가와 영상 품질의 정성적 평가 모두에서 두 집단은 유의미한 차이가 없었으나, 검사 시간의 정량적 평가에선 p값이 0.001로 유의한 차이가 있었다. 피드 및 랩 방식의 총검사 건수 대비 성공률은 100%였다. 결론적으로 본 논문에선 피드 및 랩 방식과 진정 방식의 영상 품질이 유의한 차이가 없고 성공률이 높기에 유용하다고 판단하였으나, 검사 시간이 더 지연되는 한계가 있다는 사실을 확인하였다.

Mass production of high-quality carbon nanotubes (CNTs) remains a challenge, requiring the development of new wetimpregnated catalyst suitable for the catalytic chemical vapor deposition (CCVD) of CNTs in a fluidized bed reactor. For the successful development of a new catalyst, a highly robust system to synthesize CNTs must be established. Here, we systematically investigated the robustness of CNT synthesis by CCVD using a wet-impregnated catalyst. We statistically tested four factors that could potentially affect the robustness of CNT synthesis system, focusing on carbon yield and IG/ID. First, we tested the effect of vacuum baking before CNT growth. F test and CV equality test concluded that vacuum baking recipe did not significantly reduce the variability of the CNT synthesis. Second, we tested the batch-to-batch variation of catalysts. The results of t test and one-way analysis of variance indicate that there is significant difference in carbon yield and IG/ID among catalysts from different batches. Third, we confirmed that there is spatial non-uniformity of wet-impregnated catalysts within a batch when they are produced in large scale. Finally, we developed a multi-step heating recipe to mitigate the temperature overshooting during the CNT synthesis. The multi-step recipe increased the mean of carbon yield, but did not influence the variability of CNT synthesis. We believe that our research can contribute to the establishment of a robust CNT synthesis system and development of new wet-impregnated catalysts.

In response to a regulatory mandate, all nuclear licensees are obligated to establish an information system that can provide essential information in the event of a radiation emergency by connecting the monitoring data of the Safety Parameter Display System (SPDS) or equivalent system to the Korea Institute of Nuclear Safety (KINS). Responding to this responsibility, the Korea Atomic Energy Research Institute (KAERI) has established the Safety Information Transmission System (SITS), which enables the collection and real-time monitoring of safety information. The KAERI monitors and collects safety information, which includes data from the HANARO Operation Work Station (OWS) and the HANARO & HANARO Fuel Fabrication Plant (HFFP) Radioactivity Monitoring System (RMS), and the Environmental Radiation Monitoring System (ERMS) & meteorological data. Currently, the transmission of this safety information to the AtomCARE server of the KINS takes place via the SITS server located in the Emergency Operations Facility (EOF). However, the multi-path of transmission through SITS has caused problems such as an increase in data transmission interruptions and errors, as well as delays in identifying the cause and implementing system recovery measures. To address these issues, a new VPN is currently being constructed on the servers of nuclear facilities that generate and manage safety information to establish a direct transmission system of safety information from each nuclear facility to the AtomCARE server. The establishment of a direct transmission system that eliminates unnecessary transit steps is expected to result in stable information transmission and minimize the frequency of data transmission interruptions. As of the improvement progress, a security review was conducted in the second and third quarters of 2022 to evaluate the security of newly introduced VPNs to the nuclear facility server, and based on the results of the review, security measures were strengthened. In the fourth quarter of 2022, the development of a direct transmission system for safety information began, and it is scheduled to be completed by the fourth quarter of 2023. The project includes the construction of the transmission system, system inspection, and comprehensive data stability testing. Afterward, the existing SITS located in the EOF will be renamed as the Safety Information Display System (SIDS), and there are plans to remove any unused servers and VPNs.

Employees of nuclear licensees have to take the education for radiological emergency preparedness, as prescribed by presidential Decree. The Korea Atomic Energy Research Institute (KAERI), as an educational institution designated by the Nuclear Safety and Security Commission (NSSC), has been conducting field-oriented workplace education. This aims to enhance understanding of radiological emergencies that may occur in nuclear facilities and to strengthen response capabilities to prevent and deal with accidents in the event of radiation emergencies or radioactive disasters. To accomplish these educational goals, a paradigm shift from the previous theory-oriented curriculum to a participatory curriculum with high field applicability is needed to strengthen the ability to respond to nuclear or radiological emergencies. In addition, a feedback system is required to manage the quality of education and improve the curriculum. In this regard, KAERI sought ways to revitalize the education to strengthen the emergency response competencies. Based on the concept of the Systematic Approach to Training (SAT) methodology, which is recommended by the International Atomic Energy Agency (IAEA) for the development and implementation of education and training for NPP personnel, an educational model and its feedback system were developed. Then, a field-oriented participatory curriculum operation and satisfaction survey were conducted to evaluate the educational effectiveness. Lastly, the survey results were discussed in a critique session to point out weaknesses and indicate areas for improvement, and then were used as data for educational quality assurance. This paper introduces the composition and effectiveness of KAERI’s SAT-based education model based on its recent three years of experience.

In this study, we evaluate artificial neural network (ANN) models that estimate the positions of gamma-ray sources from plastic scintillating fiber (PSF)-based radiation detection systems using different filtering ratios. The PSF-based radiation detection system consists of a single-stranded PSF, two photomultiplier tubes (PMTs) that transform the scintillation signals into electric signals, amplifiers, and a data acquisition system (DAQ). The source used to evaluate the system is Cs-137, with a photopeak of 662 keV and a dose rate of about 5 μSv/h. We construct ANN models with the same structure but different training data. For the training data, we selected a measurement time of 1 minute to secure a sufficient number of data points. Conversely, we chose a measurement time of 10 seconds for extracting time-difference data from the primary data, followed by filtering. During the filtering process, we identified the peak heights of the gaussian-fitted curves obtained from the histogram of the time-difference data, and extracted the data located above the height which is equal to the peak height multiplied by a predetermined percentage. We used percentage values of 0, 20, 40, and 60 for the filtering. The results indicate that the filtering has an effect on the position estimation error, which we define as the absolute value of the difference between the estimated source position and the actual source position. The estimation of the ANN model trained with raw data for the training data shows a total average error of 1.391 m, while the ANN model trained with 20%-filtered data for the training data shows a total average error of 0.263 m. Similarly, the 40%-filtered data result shows a total average error of 0.119 m, and the 60%-filtered data result shows a total average error of 0.0452 m. From the perspective of the total average error, it is clear that the more data are filtered, the more accurate the result is. Further study will be conducted to optimize the filtering ratio for the system and measuring time by evaluating stabilization time for position estimation of the source.

Laser cutting technology capable of remote cutting is being developed to reduce radiation exposure to workers and minimize secondary waste generation when dismantling highly polluted nuclear power plant facilities (reactors, pressurizers, steam generators, coolant pumps, etc.). Laser cutting proceeds in air or water, and at this time, secondary products containing radioactive materials are inevitably generated. In air cutting, dust and aerosol are generated, and in underwater cutting, aerosol, water vapor, dispersed particles (colloid, suspension), sediment (dross, sediment), and radioactive waste liquid are generated. Dispersed particles float in the form of fine particles in water, increasing the turbidity of water as cutting progresses, hindering work, and aerosols contain micrometer-sized particles together with water vapor, which can threaten the safety of workers. Particles dispersed in water and aerosol are within 10% of the mass ratio among secondary products, but the volume they occupy is very large, which can have a significant impact on the environment as well as a burden on treatment capacity. Various characterization methods are being developed to diagnose the generation mechanism and physical and chemical properties of laser cutting secondary products in real time and to secure technologies for collecting and removing dispersed particles and aerosols in water. This study introduces a real-time laser cutting secondary product characteristic evaluation method that can identify the key mechanisms of secondary product generation by analyzing the plasma formation process on laser cutting surface and behavior of aerosol, underwater dispersed particles produced by secondary products, as well as physical and chemical properties in real time with various measurement technologies such as Optical Emission Spectrometer (OES), Particle Size Analyzer (PSA), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDX), Transmission electron microscopy (TEM) and Inductively Coupled Plasma Time-of-Flight Mass Spectrometry (ICP-TOF-MS).

In-depth disposal of spent nuclear fuel means safe disposal of spent nuclear fuel by the concept of a multi-barrier system composed of an artificial barrier, an engineering barrier, and a natural barrier system of natural rock at a depth of less than 500 m underground. Disposal canisters are needed to store high-level waste in a deep environmental for a long time, and in order to demonstrate the performance of deep disposal canisters for spent nuclear fuel at underground research facilities (URL), it is intended to design disposal canisters and manufacture internal canisters. The internal canisters of spent nuclear fuel disposal canisters manufactured as a result of the study are combined with external copper canister technology and are directly used for demonstration of engineering barrier performance in underground facilities (URL) essential for final disposal of spent nuclear fuel. Disposal canister manufacturing technology and manufacturing process are used to manufacture disposal canisters for future final disposal projects in connection with domestic unique disposal systems. The quality inspection and quality management technology applied when manufacturing disposal canisters contribute to securing the soundness of disposal canisters that primarily maintain the safety of in-depth disposal by using them in the actual disposal business. By visually showing the development status of domestic disposal technology by displaying the prototype of disposal canisters manufactured as major achivements, the public can raise awareness of the domestic technology and safety of in-depth disposal of spent nuclear fuel.

A phosphorylation (phosphate precipitation) technology of metal chlorides is considering as a proper treatment method for recovering the fission products in a spent molten salt. In KAERI’s previous precipitation tests, the powder of lithium phosphate (Li3PO4) as a precipitation agent reacted with metal chlorides in a simulated LiCl-KCl molten salt. The reaction of metal chlorides containing actinides such as uranium and rare earths with lithium phosphate in a molten salt was known as solidliquid reaction. In order to increase the precipitation reaction rate the powder of lithium phosphate dispersed by stirring thoroughly in a molten salt. As one of the recovery methods of the metal phosphates precipitated on the bottom of the molten salt vessel cutting method at the lower part of the salt ingot is considered. On the other hand, a vacuum distillation method of all the molten salt containing the metal phosphates precipitates was proposed as another recovering method. In recent study, a new method for collecting the phosphorylation reaction products into a small recovering vessel was investigated resulting in some test data by using the lithium phosphate ingot in a molten salt containing uranium and three rare earth elements (Nd, Ce, and La). The phosphorylation experiments using lithium phosphate ingots carried out to collect the metal phosphate precipitates and the test result of this new method was feasible. However, the reaction rate of test using lithium phosphate ingot is very slower than that of test using lithium phosphate powder. In this presentation, the precipitation reactor design used for phosphorylation reaction shows that the amount of molten salt transferred to the distillation unit will reduce by collecting all of the metal phosphates that will be generated using lithium phosphate powder into a small recovering vessel.

It has been investigated on the management of the nuclides in KAERI. Strontium-90 is a high heatgenerating nuclide in spent nuclear fuel. It is needed to separate the salt from the salt solution for the recovery of strontium after the chlorination of the strontium oxide in molten salt. A vacuum distillation technology was used for the separation of strontium from the molten salt. It was investigated on operating conditions of reactive distillation process for the recovery of the strontium from the salt solution. At a reduced pressure, considerable amount of the carbonation agents such as K2CO3 and Li2CO3 were reduced during heating in the distiller due to the thermal decomposition. Therefore, the two step process was proposed, which is composed of a reaction step at an atmospheric pressure and a salt distillation step at a reduced pressure. In the reaction step, the condition of low temperature and high pressure is suitable to suppress the decomposition of the carbonation agent. In the salt distillation step, reduced pressure is preferable at a suitable temperature depending on the evaporation rate of the salt.

Considering the domestic situation where all nuclear power plants are located on seaside, the interim storage site is also likely to be located on coastal site. Maritime transportation is inevitable and the its risk assessment is very important for safety. Currently, there is no independently developed maritime transportation risk assessment code in Korea, and no research has been conducted to evaluate the release of radioactive waste due to the immersion of transport cask. Previous studies show that the release rate of radionuclides contained in a submerged transport cask is significantly affected by the area of flow path generated at the breached containment boundary. Due to the robustness of a cask, the breach is the most likely generated between the lid and body of cask. CRIEPI investigated the effect of cask containment on the release rate of radioactive contents into the ocean and proposed a procedure to calculate the release rate considering the so-called barrier effect. However, the contribution of O-ring on the release rate was not considered in the work. In this study, test and analysis is performed to determine the equivalent flow path gap considering the influence of O-rings. These results will be implemented in the computational model to assess sea water flow through a breached containment boundary using CFD techniques to assess radionuclide release rates. The evaluation of release rate due to container lid gaps has been performed by CRIEPI and BAM. In CRIEPI, the gap of the flow path was calculated from the roughness of the container surface without a quantitative assessment of the severity of the accident. In this work, to evaluate the release rate as a function of lid displacement, a small containment vessel is engineered and a metal Oring of the Helicoflex HN type is installed, which is the most commonly used one in transport and storage casks. The lid of containment vessel is displaced in vertical and horizontal direction and the release rate of the vessel was quantified using the helium leak test and the pressure drop test. Through this work, the relationship between the vertical opening displacement and horizontal sliding displacement of the cask lid and the actual flow path area created is established. This will be implemented in the CFD model for flow rate calculation from a submerged transport cask in the deep sea.

This study examined the Democratic People’s Republic of Korea (DPRK)’s illegal trade in UNsanctioned items as revealed in the UN panel of experts report in order to estimate the types of illegal trade in nuclear items, one of the UN-sanctioned prohibited items, and to find efficient ways to block it. Also, The research revealed that DPRK secretly imports UN-sanctioned prohibited items without going through customs through maritime transshipment, conceals or disguises them through identity laundering by falsifying documents at customs clearance, and makes various attempts to escape the international community’s surveillance, such as using a combination of methods such as Re-Flagged and Double-Flagged for identity laundering, and concealing them without operating the Automatic Identification System (AIS) at sea. The DPRK’s Illicit trade cases have been divided into two types of transactions: those that violate customs clearance procedures by providing false information to customs through disguise or concealment, and those that do not go through normal customs procedures, such as smuggling. To block customs violations, technical measures such as increasing the number of inspections of container ships or improving the accuracy of inspections are required, while to block smuggling, since it does not go through physical inspections, there are ways to monitor it through satellite images or strengthen border enforcement such as airport bays and land routes. As a result, DPRK’s nuclear items are designated as sanctioned items under UN resolutions, and it is assumed that DPRK and its networks will attempt to trade illegally through a combination of customs clearance violations and non-customs clearance violations, depending on the circumstances. Furthermore, since DPRK is subject to extensive sanctions from the international community, including the UN, in connection with its nuclear weapons program, illegal trade continues, and efforts should be made to block illegal trade through physical inspection at customs clearance.