• Nuclear Engineering and Technology
• /
• v.54 no.12
• /
• pp.4620-4624
• /
• 2022

Several cadmium zinc telluride (CZT) crystals were fabricated into radiation detectors using methods that included slicing, dicing, lapping, polishing, and chemical etching. A wet passivation with sodium hypochlorite (NaOCl) was then carried out on the Br-etched detectors. The Te-rich layer on the CZT surface was successfully compensated to the Te oxide layer, which was analyzed with X-ray photoelectron spectroscopy data of both a Br-etched crystal and a passivated CZT crystals. We confirmed that passivation with NaOCl improved the transport property by analyzing the mobility-lifetime product and surface recombination velocity. The electrical and spectroscopic properties of large volume detectors were compared before and after passivation, and then the detectors were observed for a month. Both bar and quasi-hemispherical detectors show an enhancement in performance after passivation. Thus, we could identify the effect of NaOCl passivation on large volume CZT detectors.

• Journal of the Korean Society for Precision Engineering
• /
• v.15 no.11
• /
• pp.251-257
• /
• 1998

동적 파괴인성치 측정시스템과 동적 2차원 유한요소해석 프로그램을 개발하여 원자로압력용기에 사용하는 강(SA508 cl.3, SA516 gr.70)의 동적 파괴인성치와 동적 균열정지인성치를 평가하고 이에 대한 유용성을 확인하였으며, 이 시스템 을 이용하여 재료의 동적 파괴특성을 규명하였다. SA508 cl.3와 SA516 gr.70의 동적 균열전파속도(a)에 대응하는 동적 응력확대계수 (K(a))에 대한 실험식을 얻었으며, 동적 응력확대계수와 동적 균열전파속도와의 관계는 전형적인 "$\Gamma$" 형으로 나타남을 확인하였다.

• Nuclear Engineering and Technology
• /
• v.55 no.12
• /
• pp.4472-4476
• /
• 2023

In this study, it has been shown that the true coincidence summing correction factor can be obtained for the first time using the PHITS Monte Carlo program. Determining this correction factor using different methods and tools in each laboratory to increase the possibility of achieving high-efficiency measurement conditions is still popular in gamma-ray spectrometry. By using ¹³³Ba, ¹⁵²Eu, ¹³⁴Cs, and ⁶⁰Co point sources, the true coincidence summing factor was investigated in both near and far counting geometries for 15 different energy values. GESPECOR software was used to validate the results obtained with PHITS. A remarkable agreement was obtained between PHITS and GESPECOR, with a discrepancy of less than 3%. With this study, a new tool has been proposed to obtain the true coincidence summing factor, which is one of the significant correction factors investigated/calculated in gamma-ray spectrometric studies.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.15 no.2
• /
• pp.135-149
• /
• 2017

Demonstration programs for spent nuclear fuel dry storage have been carried out to produce important and confirmatory data to support safety of dry storage systems and integrity of spent nuclear fuel stored in dry condition. The US initiated the dry storage of spent nuclear fuel and has strict and explicit regulatory stipulations on the integrity of spent nuclear fuel in dry storage. The US has carried out several notable demonstration programs for the initiation and license extension of dry storage. At the very early stage of dry storage, the demonstration programs were focused on proof of the safety of dry storage systems and a demonstration project called the dry cask storage characterization project was performed for the license extension of low burn-up fuel dry storage. Currently, a demonstration program for the license extension of high burn-up fuel dry storage is under way and is expected to continue for at least 10 years. Korea has not yet begun the dry storage of PWR fuel and the US programs can be a good reference and can provide lessons to safely begin and operate dry storage in Korea. In this paper, past and current demonstration programs of the US are analyzed and several recommendations are provided for demonstration programs for the dry storage of spent nuclear fuel in Korea.

• Nuclear Engineering and Technology
• /
• v.39 no.1
• /
• pp.31-42
• /
• 2007

Energy supply is increasingly showing up as a major issue for electricity supply, transportation, settlement, and process heat industrial supply including hydrogen production. Nuclear power is part of the solution. For electricity supply, as exemplified in Finland and France, the EPR brings an immediate answer; HTR could bring another solution in some specific cases. For other supply, mostly heat, the HTR brings a solution inaccessible to conventional nuclear power plants for very high or even high temperature. As fossil fuels costs increase and efforts to avoid generation of Greenhouse gases are implemented, a market for nuclear generated process heat will be developed. Following active developments in the 80's, HTR have been put on the back burner up to 5 years ago. Light water reactors are widely dominating the nuclear production field today. However, interest in the HTR technology was renewed in the past few years. Several commercial projects are actively promoted, most of them aiming at electricity production. ANTARES is today AREVA's response to the cogeneration market. It distinguishes itself from other concepts with its indirect cycle design powering a combined cycle power plant. Several reasons support this design choice, one of the most important of which is the design flexibility to adapt readily to combined heat and power applications. From the start, AREVA made the choice of such flexibility with the belief that the HTR market is not so much in competition with LWR in the sole electricity market but in the specific added value market of cogeneration and process heat. In view of the volatility of the costs of fossil fuels, AREVA's choice brings to the large industrial heat applications the fuel cost predictability of nuclear fuel with the efficiency of a high temperature heat source tree of Greenhouse gases emissions. The ANTARES module produces 600 MWth which can be split into the required process heat, the remaining power drives an adapted prorated electric plant. Depending on the process heat temperature and power needs, up to 80% of the nuclear heat is converted into useful power. An important feature of the design is the standardization of the heat source, as independent as possible of the process heat application. This should expedite licensing. The essential conditions for success include: ${\bullet}$ Timely adapted licensing process and regulations, codes and standards for such application and design ${\bullet}$ An industry oriented R&D program to meet the technological challenges making the best use of the international collaboration. Gen IV could be the vector ${\bullet}$ Identification of an end user(or a consortium of) willing to fund a FOAK

• Korean Journal of Veterinary Research
• /
• v.46 no.4
• /
• pp.305-313
• /
• 2006

The primary goal of the wound healing is rapid wound closure. Recent advances in cellular and molecular biology have greatly expanded our understanding of the biologic processes involved in wound repair and tissue regeneration. This study was conducted to develop a new sponge type of biomaterial to be used for either wound dressing or scaffold for tissue engineering. We designed to make a comparative study of the wound healing effect of silk fibroin/hyaluronic acid (SF/HA) blend sponge in full-thickness dermal injury model of rat. Two full-thickness excisions were made on the back of the experimental animals. The excised wound was covered with either the silk fibroin (SF), hyaluronic acid (HA) or SF/HA (7 : 3 or 5 : 5 ratio) blend sponge. On the postoperative days of 3, 7, 10 and 14, the wound area was calculated by image analysis software. Simultaneously, the tissues were stained with Hematoxylin-Eosin and Masson's trichrome methods to measure the area of regenerated epithelium and collagen deposition. In addition, we evaluated the degree of the epithelial cell proliferation using immunohistochemistry for proliferating cell nuclear antigen (PCNA). We found that the half healing time ($HT_{50}$) of SF/HA blend sponge treated groups were significantly decreased as compared with either those of SF or HA treatment group. Furthermore, SF/HA blend sponges significantly increased the size of epithelialization and collagen deposition as well as the number of PCNA positive cells on epidermal basement membrane as compared with those of control treatment. Especially, the 5 : 5 ratio group of SF/HA among all treatment groups was most effective on wound healing rate and histological studies. These results suggest that SF/HA blend sponges could accelerate the wound healing process through the increase of epithelialization, collagen deposition and basal cell proliferation in full thickness skin injury.

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2005.06a
• /
• pp.205-210
• /
• 2005

The proposed regulation for low and intermediate level radioactive waste disposal facility, scheduled to be revised, recommends that the waste generator should verify the radioactive waste conforms to the disposal requirements before disposing of it. According to the regulation, the radionuclide concentration of the radioactive waste, and its physical and chemical characteristics and safety must be confirmed prior to the disposal of low and intermediate level radioactive wastes, and the waste generator is required to deliver this information to the disposal facility operator. In addition, the disposal facility operator must assess the safety of the disposal site to establish the SWAC (Site Specific Waste Acceptance Criteria) in consideration of the characteristics of the site, whereas the waste generator must comply with the criteria in managing, disposing of and delivering low and intermediate level radioactive wastes. To abide by the afore-mentioned regulation and criteria, the waste generator must verify that the radioactive wastes to be disposed of are suitable for disposal before they are transported to the disposal facility, and to this end a radioactive waste certification program must be developed. This study conducted an in-depth analysis of the radioactive waste certification programs enforced in countries advanced in atomic energy to develop a draft of a certification program applicable to local power plants, and the program is currently applied as pilot to Uljin Power Plants No. 1 & 2 to prove its applicability. This study is going to analyze the results of the pilot application with a view to developing a radioactive waste certification program suitable to local conditions.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.27 no.5
• /
• pp.429-436
• /
• 2014

This paper presents the seismic performance of a geometrically unsymmetrical reinforced concrete building considering torsional effect and material nonlinearity of concrete and steel. The reinforced concrete building is a structure for seismic performance evaluation in the SMART-2013 international benchmark program. Nonlinear constitutive models for concrete and steel were constructed, and their numerical performance was demonstrated by various local tests. Modal analysis showed that the first three natural frequencies and mode shapes were close to the experimental results from the SMART-2013 program. In the time history analysis for low-intensity seismic loadings, displacement and acceleration responses at sampling points were similar to the experimental results. In the end, nonlinear time history analysis was conducted for Northridge earthquake to predict the behavior of the reinforced concrete structure under high-intensity seismic loadings.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2013.04a
• /
• pp.589-595
• /
• 2013

A reactor vessel internals comprehensive vibration assessment program(RVI CVAP) of an advanced power reactor 1400(APR1400) is being verified on the integrity of RVI for the design life of the plant by performing the non-prototype category-2 type on the US Nuclear Regulatory Commission Guide(NRC RG) 1.20, for which consists of a vibration and stress analysis program, a limited vibration measurement program, an inspection program, and the correlation of these programs. The aim of this paper is to describe the plan for the vibration measurement, test and acceptance criteria portion, and documentation and results of the APR1400 RVI CVAP. We will conduct the limited vibration measurement program of the APR1400 RVI CVAP according to the measurement plan and the vibration measurement testing in this paper.

• Applied Microscopy
• /
• v.48 no.1
• /
• pp.1-5
• /
• 2018

Cryo-transmission electron microscopy (cryo-TEM) allows us to perform structural analysis of a analyses of large protein complexes, which are difficult to analyze using X-ray crystallography or nuclear magnetic resonance. The most common examples of proteins used are ribosomes and proteasomes. In this paper, we briefly describe the advantage of cryo-TEM and the process of two-dimensional classification by considering a human proteasome as an example.