Radiation workers receive exposure during radiation works such as decontamination or cutting of metals and concrete in decommissioning nuclear power plants. To reduce occupational exposure, various radiation protection measures should be prepared by estimating the exposure dose in advance. RESRAD-RECYCLE, the computer code, is generally used for estimating occupational dose due to handling metals contaminated with radioactive materials. However, RESRAD-RECYCLE used the dose conversion factors (DCF) of EPA FGR No. 11 based on ICRP Publications 30 and 48 published in the 1980s for internal exposure estimation. This study compared the DCFs of RESRAD-RECYCLE with those of the relatively recently published ICRP Publications 119 and 141. In addition, the internal exposure dose was evaluated by changing the value of the DCFs of RESRAD-RECYCLE. As a result of the comparison, ICRP Publication 119 showed that the DCF values of most nuclides were significantly lowered. On the other hand, in the case of nuclides emitting gamma rays, there was generally no significant change in the value of DCFs. In addition, in the case of 65Zn and 94Nb, the DCF increased compared to the previous ICRP publications. The exposure dose of the decommissioning workers of Hanul Units 1 and 3 and Hanbit Unit 4 was also calculated in this study. The expected radioactivity concentration of the steam generator chamber of each unit was used as the source term. The concentration of metal dust in the air generated during cutting was calculated and applied to evaluate the internal exposure dose. As a result of the dose evaluation, there was a difference in exposure dose up to 0.2 mSv in the scrap cutter scenario of Hanbit Unit 4, which generated a lot of dust and had a high radioactivity concentration. On the other hand, in the case of the slag worker, there was no difference in the dose because the working time was very short, and the inhalation of metal dust was small, even if the latest DCF was applied.

It is expected that around 576,000 bundles of CANDU spent nuclear fuels (SNF) will be generated from the four CANDU reactors located at the Wolsong site, according to the 2nd National Plan for the management of High-Level radioactive Waste (HLW). The CANDU SNFs are currently stored at the dry storage facilities at the Wolsong site. The authors proposed KRS+ geological disposal system consisting of two different concepts, Swedish KBS-3V type and Canadian NWMO type, for the final management of CANDU SNF. Both the concepts were designed based on the geological data obtained from the KURT (KAERI Underground Research Tunnel). The NWMO type is an in-room horizontal placement method. In this study, we try to determine the reference concept among the two proposed concepts at 500 meters below the ground surface. Assuming 10,000 tU of CANDU SNF and the KURT site, we design two engineered barrier systems, that is disposal canisters and buffers. The copper disposal canister is designed with a copper thickness of 10 mm based on a cold spray coating technique for both the disposal concepts. The domestic Ca-bentonite is used for the compact bentonite buffer with dry density of 1.6 g/cm3. Two concepts are compared in terms of safety, economics of the engineered barriers, and environment-friendliness. Because the same amounts of CANDU SNF are disposed of at the same depth, the differences in the disposal area are neglected. For the comparison in terms of safety, the corrosion lifetimes of the disposal canisters of two disposal systems are quantitatively calculated, and the capacities for retarding radionuclide releases of the compacted bentonite buffers are assessed. A computer tool developed by the authors is used in order to assess the lifetime of a disposal canister. In this study, the case that corrosion of a copper canister by sulfide from groundwater through intact buffer is analyzed. The sulfide concentration in groundwater is assumed to be 3 ppm. The most important safety function of buffer is to retard the radionuclide release. Twelve long-lived radionuclides are selected to compare the capacities for retarding the radionuclide transport through the buffer using an analytical solution. The retention time by an engineered barrier consisting of a disposal canister and a buffer is compared with twenty times the half-life of each radionuclide for both the disposal systems. The selected reference concept will be compared with the alternative geological concepts through a further study.

In the design of a spent-fuel (SF) storage, the consideration of burnup credit brings the benefits in safety and economic views. According to it, various SF burnup measurement systems have been developed to estimate high fidelity burnup credit, such as FORK and SMOPY. Recently, there are a few attempts to localize the SF burnup measurement system in South Korea. For the localization of SF burnup measurement systems, it is very important to build the isotope inventory data base (DB) of various kinds of SFs. In this study, we performed DeCART2D/MASTER core follow calculations and McCARD single fuel assembly (FA) burnup analyses for Hanbit unit 3 and confirmed the characteristic of the isotope inventory over burnup. Firstly, the core follow calculations for Cycles 1~7 were performed using DeCART2D/MASTER code system. The core follow calculation is very realistic and practical because it considers the design conditions from its nuclear design report (NDR). Secondly, the Monte Carlo burnup analyses for single FAs were conducted by the McCARD Monte Carlo (MC) transport code. The McCARD code can utilize continuous energy cross section library and treat complex geometric information for particle transport simulation. Accordingly, the McCARD code can provide accurate solutions for burnup analyses without approximations, but it needs huge computing resources and time burden to perform whole-core follow calculations. Therefore, we will confirm the effectiveness of the single McCARD FA burnup analyses by comparing the DeCART2D/MASTER core follow results with the McCARD solution. From the results, the use of single FA burnup analyses for the establishment of the DBs will be justified. Various FAs, that have different 235U enrichments and loading pattern of fuel rods and burnable absorbers, were considered for the burnup analyses. In addition, the results of the sensitivity analyses for power density, initial enrichment, and cooling time will be presented.

According to the ‘Basic Plan for High-Level Radioactive Waste Management (draft)’, the total amount of CANDU spent nuclear fuel is expected to be approximately 660,000 bundles. To safely and efficiently transport this amount to interim storage facilities, it is essential to develop a large-capacity transport cask. Therefore, we have been developing a large-capacity PHWR spent nuclear fuel transport cask, called the KTC-360 transport cask. According to the transport-cask related regulations, the KTC-360 transport cask was classified as a Type B package, and such packages must be able to withstand a temperature of 800°C for a period of 30 min. It is desirable to conduct a test using a fullscale model of a shipping package when performing tests to evaluate its integrity. However, it is costly to perform a test using a full-scale model. Therefore, to evaluate the thermal integrity of the KTC-360 transport cask, the fire test was conducted using a slice model. For comparison purposes, the fire test was also carried out using a 1/4 scale model. In the fire test using a slice model and in the fire test using a 1/4 scale model, the maximum temperature of the cask body was lower than the permitted maximum temperature limit. Therefore, the thermal integrity of the KTC-360 transport cask could be considered to be maintained. The temperature results from the fire test using a slice model were higher than those of the fire test using a 1/4 scale model. Therefore, the effect of flame on a transport cask without combustible materials, such as the KTC-360 transport cask, seems to be affected by the reduction in the time rather than the size reduction.

The slaughter of livestock is inevitably required to obtain meat products from livestock. Since slaughter means pain and death for animals, reducing the pain and distress of animals during slaughter is very important from a perspective of animal welfare based on the principle of respect for life. Generally, two stunning methods, CO2 stunning and electrical stunning, are used for slaughter. When the carotid arteries of the lungs are cut off for bleeding, the bronchial tubes are also severed. To determine the degree of blood inflow into the lungs through the severed bronchial tubes, the prevalence rates of pulmonary diseases and pulmonary congestion in slaughtered pigs were analyzed. In this study, the prevalence of pneumonia was 24.9% in Slaughterhouse A using the gas method, but it was decreased by about 10% to 15.7% and 12.6%, respectively, in Slaughterhouses B and C using the electric method. On the other hand, the prevalence of pulmonary congestion in Slaughterhouses A, B, and C was 4.24%, 14.10% and 16.40%, respectively. In other words, the prevalence of pulmonary congestion was higher by about 10% in the groups of pigs slaughtered by the electric method (Slaughterhouses B and C) than in the group of pigs slaughtered by the gas method (Slaughterhouse A). These results indicate that blood inflow into the pulmonary alveoli led to a diagnosis of pulmonary congestion instead of pneumonia in some pigs with pneumonia. In short, it was found that about 10% of pigs stunned by the electric method were not in a state of complete unconsciousness but in a partially conscious state during slaughter. It is suggested that slaughterhouses should be equipped with gas stunning equipment instead of applying the electric method due to lower costs.

본 연구는 『等级标准』의 중국어 교육문법 요목인 『等级标准(语法)』의 중국어 교육 문법 요목의 체계를 살펴보기 위해 『语法等级大纲(1996)』및 『国际大纲(语法)(2014)』을 HSK과의 연계성, 문법범주 및 문법항목, 등급체계 및 등급 배열을 기준으로 비교 분석하였다. 그 결과 첫째, HSK1.0단계는 중국어 요목 기준, 문법 요목과 연계된 평가요목은 별도로 제정되지 않았고, 등급도 일치하지 않는다. HSK2.0단계는 교육 문법 요목과 연계된 HSK요목은 별도로 제정되었고, 6등급으로 일치시켰다. HSK3.0단계의 『等级标准(语法)』에서는 교육 문법 요목과 HSK요목을 3등 9급 체계로 동일하게 일치시켰다. 『等级标准(语法)』의 등급체계 변화는 국내 중국어교육에도 영향이 있다. 특히 큰 HSK 급수 변화에 따른 학습자의 혼란이 야기되고, 중국어 교육과정, 강의, 시험 및 평가 등에도 변화에 따른 연구가 필요하다. 둘째, 『等级标准(语法)』의 교육문법 체계는 HSK1.0단계의 『语法等级大纲(1996)』과 거의 일치함으로 형태론 및 통사론 중심의 문법항목 중심으로 중국어의 특징이 충분히 반영되었다. 『等级标准(语法)』을 한국인 학습자를 중국어교육에 반영하기 위해서는 적절성, 효율성, 통용성에 대해 고려해 보아야 할 것이다. 셋째, 『语法等级大纲(1996)』, 『国际大纲(语法)(2014)』, 『等级标准(语法)』의 모두 전반적 상대적 등급 배열, 누적식 등급 배열은 전반적으로 이루어졌다. 하지만 『等级标准(语法)』을 한국인 학습자 중국어교육에 적용하기 위해서 3등 9급으로 변화된 체계에 적절한 문법항목의 선정, 난이도 고려, 등급 배열 등이 고려되어야 할 것이다. HSK도 3등 9급으로 시행되기 시작한 현시점에서 『等级标准(语法)』을 한국인 중국어교육에 적용하기 위해서는 수준별 문법항목 선정, 내용, 기술 방법 등에 관한 연구가 필요하다고 여겨진다.