원자력발전소(원전) 시스템 내진성능 평가를 위하여 구조물내응답스펙트럼(ISRS)은 필수적으로 요구된다. 특히, 원전 부지 고유 스펙트럼 변경 시 새로운 ISRS 도출이 요구될 경우 지진 재해석 등의 상당한 비용을 필요로 하게 된다. 따라서 이 연구는 지진 재해석 이 필요 없는 ISRS 스케일링 근사 방법에 대한 여러 가지 접근법을 제공한다. 이러한 접근법으로 도출한 ISRS는 정확한 ISRS와 비교 한다. 근사 방법의 ISRS 가 원전 주요 시스템 지진응답 및 내진성능에 미치는 영향을 분석한다. 결과적으로 본 연구에서 제시한 ISRS 스케일링 근사 방법은 저주파에서 비교적 유사하게 ISRS를 도출하지만, 고주파에서는 그 정확도가 감소하였다. ISRS 스케일링 근사 방법이 시스템 지진응답/내진성능 산출 정확도에 미치는 영향은 방법의 시스템 주요 모드 응답 유사도 산출 정도에 따라 결정된 것을 확인할 수 있었다.

To evaluate the inventory of radionuclides for the disposal of waste generated from nuclear power plants, indirect assessment methods such as the scaling factor method or average radioactivity concentration method can be applied. A scaling factor represents the average concentration ratio between key radionuclides and difficult-to-measure (DTM) radionuclides, while the average radioactivity concentration refers to the average concentration of DTM radionuclides, regardless of the concentration of key radionuclides or within specific ranges of key radionuclide concentrations. These indirect assessment methods can be statistically derived through the analysis of representative drums. This study will address how to apply these scaling factors and average radioactivity concentrations. Firstly, the concentration of gamma-emitting radionuclides will be analyzed using a drum radionuclide analyzer, and the concentration of DTM radionuclides will be determined by applying scaling factors specific to each DTM radionuclide. In the case of using the average radioactivity concentration method, the average concentration of DTM radionuclides will be applied independently of the concentration of gamma-emitting radionuclides. It is crucial to perform radioactive decay correction based on the date of generation or disposal when applying scaling factors or average radioactivity concentration. Additionally, for repackaged 320 L drums, determining which drum among the two 200 L drums inside should serve as the reference is of utmost importance

Domestic nuclear power plants developed the scaling factors for the radioactive waste generated from 2004 to 2008 for the first time. Afterwards, the effectiveness of continuous application of the scaling factors have been evaluated for newly generated radioactive waste over the past two years. It was confirmed that most of the initially developed scale factors were effective within a factor of 10 principle, which is an acceptable range. The scaling factors were updated using the analysis data base from 2004 to 2016. A scaling factor refers to the calculated abundance ratio between Key (Easy-to- Measure) and DTM (Difficult-to-Measure) nuclide at the time of generation of radioactive waste based on the source term in the reactor of an operating nuclear power plant. The effectiveness of continuous application of scaling factors can be evaluated at regular intervals regardless of operation status or when there are events that change scaling factors during nuclear power plant operation, such as zinc injection, large-scale facility replacement, and long-term shutdown etc. Even in the case of a permanently shut down nuclear power plant in which fuel is withdrawn from the reactor and generation of new nuclides by nuclear fission and radiation has stopped, periodic verification is conducted to confirm whether the scaling factor developed before permanent shutdown can be effectively applied to the radioactive waste generated after permanent shutdown. However, depending on the nuclear power plant decommissioning strategy or conditions, the period of permanent shutdown prior to decommissioning can be very long, so preparations are needed to ensure the appropriateness of scaling factor operation. In the case of domestic nuclear power plants, Kori Unit 1, a light water reactor, was permanently shut down in June 2017, and as a heavy water reactor nuclear power plant, the permanent shutdown of Wolseong Unit 1 was finally decided in December 2019 after twists and turns including large-scale facility replacement and long-term shutdown. In this paper, we have predicted when the scaling factors will change significantly due to radioactive decay and the difference in halflife between the Key and DTM nuclides over time after permanent shutdown. We also have tried to find appropriate countermeasures for the operation of scaling factors during permanent shutdown period, such as updating scaling factors or applying correction factors.

For safeguarding dry storage facilities, a tomography system based on fast and thermal neutron detection was studied in Korea Institute of Nuclear Nonproliferation and Control. The study was conducted laboratory-scale experiments based on a custom built 1/10th scale model cask, He-4 gas scintillation detector array, and multiple 252Cf sources. A filtered back projection (FBP) was utilized to obtain the cask image via MATLAB. The Ram-Lak filter (ramp filter) was employed in FBP for improved the reconstructed image quality. The Ram-Lak filter is the increasing amplitude filter due to the increasing spatial frequency of the image. In spatial frequency, the frequency of brightness change in the low-frequency region is relatively low, and the frequency of brightness change in the highfrequency region is large. Thus, the high-frequency region in the neutron tomographic image is near the neutron sources and the cask, and the low-frequency region is outside of the cask and/or between the source and cask in the study. In order to apply the ramp filter, a Fourier transform is initially performed on projection data, and image reconstruction is performed with the corrected projection data. In this case, the filter is linearly changed. Therefore, a small filter value is applied at lower spatial frequencies to reduce the projection data, and a large filter value is applied at high spatial frequencies to reduce the projection data. The filter scale is a fraction of frequency amplitude, and the filter value applied to the projection data is determined according to the filter scale. This study was conducted for discussion of the image quality due to the effect of the filter scale used for image reconstruction of a neutron tomography system. The results show that in the experiment with one source, the source location was founded when we used the frequency scale of 0.5 and over. In the double or triple source experiment, the source locations and relative activities were found when we used a filter scale of 0.4 to 0.6. When the filter frequency scale of 0.7 to over, the relative activities are hard to know. It can be found that if the filter value is too large or too small, distortion may occur in the reconstruction results. Therefore, it seems reasonable to set a value between 0.4 and 0.6 as the scaling factor for the neutron tomography system. In the future, additional comparative studies will perform validation of the frequency scaling methods.

이전 정서연구에서는 다양한 정서유발자극을 이용한 정서 차원 연구들을 통해 쾌불쾌 차원(valence)과 각성 차원 (arousal)이란 두 가지의 핵심정서(core affect) 차원을 밝혔다. 최근 등장한 ASMR은 심리적 안정감, 편안함 등의 정서를 유발하는데, 이런 새로운 자극 또한 핵심정서차원에 위치하는지, 사람들에게 일으키는 정서표상은 어떤 양상 을 보이는지 확인하고자 하였다. 본 연구는 3가지 정서유형(부정, 중립, 긍정)으로 구분한 ASMR 영상을 자극으로 사용하였다. 연구1에서는 청각 ASMR, 연구2에서는 청각 및 시청각 ASMR을 자극으로 사용하였고, 각 자극마다 10가지의 형용사에 대해 5점 리커트 척도로 정서경험을 보고받았다. 자료수집 이후 다차원척도법과 분류분석을 실시 하였다. 다차원척도법 결과, 청각 및 시청각 ASMR 모두 핵심정서차원인 쾌불쾌 차원에서 잘 구분되었다. 분류분석 결과, 동일한 감각양상 및 서로 다른 감각양상의 ASMR에 대한 참가자 개인의 정서표상 구분과 참가자들간 정서표 상 구분이 잘 이뤄졌다. 종합적으로 본 연구는 다른 정서유발자극들과 같이 ASMR 또한 핵심정서차원에 위치한다는 것을 시사한다는 점에서 기존의 Russell(1980)의 핵심정서차원 이론을 지지한다. 또한, 감각양상에 상관없이 ASMR 에 대한 참가자 개인의 정서표상이 예측가능하며, 참가자들의 정서표상이 일관적이라는 점을 시사한다.

The overestimation and underestimation of the radioactivity concentration of difficult-to-measure radionuclides can occur during the implementation of the scaling factor (SF) method because of the uncertainties associated with sampling, radiochemical analysis, and application of SFs. Strict regulations ensure that the SF method as an indirect method does not underestimate the radioactivity of nuclear wastes; however, there are no clear regulatory guidelines regarding the overestimation. This has been leading to the misuse of the SF methodology by stakeholders such as waste disposal licensees and regulatory bodies. Previous studies have reported instances of overestimation in statistical implementation of the SF methodology. The analysis of the two most popular linear models of the SF methodology showed that severe overestimation may occur and radioactivity concentration data must be dealt with care. Since one major source of overestimation is the use of minimum detectable activity (MDA) values as true activity values, a comparative study of instrumental techniques that could reduce the MDAs was also conducted. Thermal ionization mass spectrometry was recommended as a suitable candidate for the trace level analysis of long-lived beta-emitters such as iodine-129. Additionally, the current status of the United States and Korea was reviewed from the perspective of overestimation.

기존의 얼굴 정서자극을 이용한 정서 차원연구에서는 쾌불쾌차원(valence)과 각성차원(arousal)이라는 두 가지의 핵심정서(core affect)의 구조가 밝혀졌는데, 이러한 정서차원 구조가 일반적인 지, 그렇지 않다면 정서차원 인식에 영향을 미치는 요인은 무엇인지 파악할 필요가 있다. 본 연구에서는 얼굴 자극의 연령이 주요한 요인 중 하나라고 정하고, 6가지 정서 표현(화난, 역겨운, 두려운, 행복한, 중립적인, 슬픈)이 세 연령(청년, 장년, 노년)층에 차이가 있는지 살펴보았다. 기존 연구에서는 두 얼굴 자극의 유사성을 직접 물어보는 경우가 많았는데, 본 연구에서는 정서 간 유사성 을 직접 측정하지 않고 두 가지 얼굴 자극이 함께 제시될 때 두 정서 표현이 같은지 다른지에 대한 판단을 하도록 하는 간접적인 측정을 하였다. 각 연령별 데이터를 다차원척도법으로 분석한 결과, 세 연령대 모두 화난-역겨운, 그리고 슬픈-역겨운 정서쌍이 유사성이 높았다. 연령간 차이로는 노년 정서자극에 대해서 위 두 쌍 외에 화난-슬픈, 화난-중립적 인, 중립적인-슬픈, 역겨운-두려운의 정서쌍에 대해서도 유사성이 높음을 확인하였으며 이러한 경향은 나머지 두 연령 대에서는 발견되지 않았다. 같은 정서 쌍에 대한 결과에서는 ‘슬픈’이 노년층에서만 정확도가 매우 낮았으며, 이는 슬픔을 표현하는 노년층의 얼굴 정서를 쉽게 구분하기 어렵다는 점을 시사한다. 본 연구는 두 얼굴 정서에 대해 직접적 인 유사성을 묻는 것이 아닌, 정서 판단을 통해 간접적으로 정서 간 유사성을 유도하는 방법으로도 정서 차원 연구가 시사한다. 또한 여러 연령 별로 전반적으로는 쾌불쾌, 각성이라는 주요 정서 차원이 잘 드러나지만 노년층의 특정 정서 표현에 대한 인식이 다른 연령대의 정서 표현보다는 차이가 있을 수 있음을 보여준다.

국내 멸종위기 어류 25종의 먹이원을 문헌 조사한 결과, 먹이원은 20문, 31강, 58목, 116과, 154속으로 나타났다. 먹이원 중 가장 많은 어류가 섭식한 먹이원은 분류군에 따라 절지동물문, 곤충강, 파리목, 깔따구과로 조사되었으며, 식물류 먹이원은 돌말문, 윷돌말강, 반달돌말목, 반달돌말과로 조사되었다. 계층적 군집분석과 NMDS를 이용하여 멸종위기 어류 20종의 먹이원 유형화 결과, 어류를 주로 포식하는 충식성 어류와 식물플랑크톤을 섭식하는 어류 2가지 유형으로 나타났다. 네트워크 분석의 허브 점수가 높은 먹이원은 파리목, 하루살이목, 날도래목, 강도래목, 딱정벌 래목으로 나타났으며 식물류 먹이원 중 허브 점수가 높은 쪽배돌말목과 반달돌말목, 김발돌말목으로 조사되었다. 먹이원 폭이 큰 어류는 연준모치 (PP)와 열목어, 좀수수치, 가는돌고기, 꼬치동자개, 퉁사리, 묵잡자루, 미호종개로 Bi 지수 값이 0.3 이상으로 조사되어 다양한 먹이를 먹는 것으 로 조사되었다. 반면, 금강모치, 부안종개, 감돌고기, 흰수마자, 다묵장어, 돌상어, 얼룩새코미꾸리, 북방종개는 Bi 지수 값이 0.1 이하로 조사되어 먹이원 다양성이 낮게 조사되었다.

The radionuclide inventory in radioactive waste from nuclear power plants should be determined to secure the safety of final repositories. As an alternative to time-consuming, labor-intensive, and destructive radiochemical analysis, the indirect scaling factor (SF) method has been used to determine the concentrations of difficult-to-measure radionuclides. Despite its long history, the original SF methodology remains almost unchanged and now needs to be improved for advanced SF implementation. Intense public attention and interest have been strongly directed to the reliability of the procedures and data regarding repository safety since the first operation of the low- and intermediate-level radioactive waste disposal facility in Gyeongju, Korea. In this review, statistical methodologies for SF implementation are described and evaluated to achieve reasonable and advanced decision-making. The first part of this review begins with an overview of the current status of the scaling factor method and global experiences, including some specific statistical issues associated with SF implementation. In addition, this review aims to extend the applicability of SF to the characterization of large quantities of waste from the decommissioning of nuclear facilities.

The extended slip-weakening model was investigated by using a compiled set of source-spectrum-related parameters, i.e. seismic moment Mo, S-wave velocity Vs, corner-frequency fc, and source-controlled high-cut frequency fmax, for 113 shallow crustal earthquakes (focal depth less than 25 km, MW 3.0~7.5) that occurred in Japan from 1987 to 2016. The investigation was focused on the characteristics of stress drop, radiation energy-to-seismic moment ratio, radiation efficiency, and fracture energy release rate, Gc. The scaling relationships of those source parameters were also investigated and compared with those in previous studies, which were based on generally used singular models with the dimensionless numbers corresponding to fc given by Brune and Madariaga. The results showed that the stress drop from the singular model with Madariaga’s dimensionless number was equivalent to the breakdown stress drop, as well as Brune’s effective stress, rather than to static stress drop as has been usually assumed. The scale dependence of stress drop showed a different tendency in accordance with the size category of the earthquakes, which may be divided into small-moderate earthquakes and moderate-large earthquakes by comparing to Mo = 1017~1018 Nm. The scale dependence was quite similar to that shown by Kanamori and Rivera. The scale dependence was not because of a poor dynamic range of recorded signals or missing data as asserted by Ide and Beroza, but rather it was because of the scale dependent Vr-induced local similarity of spectrum as shown in a previous study by the authors. The energy release rate Gc with respect to breakdown distance Dc from the extended slip-weakening model coincided with that given by Ellsworth and Beroza in a study on the rupture nucleation phase; and the empirical relationship given by Abercrombie and Rice can represent the results from the extended slip-weakening model, the results from laboratory stick-slip experiments by Ohnaka, and the results given by Ellsworth and Beroza simultaneously. Also the energy flux into the breakdown zone was well correlated with the breakdown stress drop,   and peak slip velocity of the fault faces. Consequently, the investigation results indicate the appropriateness of the extended slip-weakening model.