Revisit of LLD Requirements for Airborne Discharges From PWRs in Line With Effluent Concentration Limit

Soyun Kim,Jae Hak Cheong 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.1

Radioactive effluent discharged from the nuclear power plant (NPP) during normal operation is controlled by the discharge limit in terms of radioactivity concentration (Bq·m?3) and dose constraints in Korea. To ensure compliance with discharge limits of effluents, the licensee operates radioactive effluent monitoring systems in each discharge point to detect radioactivity and control discharge. The predetermined regulatory requirements of analytical sensitivities for sampling devices in the monitoring system are established in various countries to guarantee the performance of the monitoring systems. In Korea, Lower Limits of Detection (LLD) are selected as the regulatory requirements and adopted from the United States Nuclear Regulatory Commission (USNRC) NUREG-1301. The International Atomic Energy Agency stated that the detection limits have to be low enough (e.g., less than 1% of discharge limits) to safely demonstrate compliance with the discharge limits. However, no technical background of LLD has been explained regarding the compliance with discharge limits in Korea. Thus, it is necessary to analyze the compatibility of discharge limits and detection limits. The USNRC Regulatory Guide 1.21 has stated the risk-informed approach for effluent control by identifying the principal radionuclides whose radiological impact is more than 1% of discharge limits. In 2017, Cheong proposed the methodology and derived risk-based detection limits for liquid effluents from Korean NPPs. In 2019, Choi derived risk-based detection limits for liquid and gaseous effluents based on APR 1400 Design Control Document (DCD). The methodology of those studies can derive the detection limit for each principal radionuclide that is comparable to 1% to 10% of discharge limits. However, the previous study based on APR 1400 DCD was for the discharge limits of the US and didn’t consider the multiple discharge points in the reactor. Therefore, this study preliminarily derived the risk-based detection limits consistent with Korean Effluent Concentration Limits for gaseous effluents reflecting the characteristics of each discharge point. Also, this study confirmed the validity of risk-based detection limits and current LLD. This study is expected to be basic research for detection limits of Korean NPPs in line with international safety standards.

Limit-cycle 항법과 모서리 검출을 기반으로 하는 UGV를 위한 계획 경로 알고리즘

임윤원(Yun-Won Lim),정진수(Jin-Su Jeong),안진웅(Jin-Ung An),김동한(Dong-Han Kim) 제어로봇시스템학회 2011 제어·로봇·시스템학회 논문지 Vol.17 No.5

This UGV (Unmanned Ground Vehicle) is not only widely used in various practical applications but is also currently being researched in many disciplines. In particular, obstacle avoidance is considered one of the most important technologies in the navigation of an unmanned vehicle. In this paper, we introduce a simple algorithm for path planning in order to reach a destination while avoiding a polygonal-shaped static obstacle. To effectively avoid such an obstacle, a path planned near the obstacle is much shorter than a path planned far from the obstacle, on the condition that both paths guarantee that the robot will not collide with the obstacle. So, to generate a path near the obstacle, we have developed an algorithm that combines an edge detection method and a limit-cycle navigation method. The edge detection method, based on Hough Transform and IR sensors, finds an obstacle’ edge, and the limit-cycle navigation method generates a path that is smooth enough to reach a detected obstacle’ edge. And we proposed novel algorithm to solve local minima using the virtual wall in the local vision. Finally, we verify performances of the proposed algorithm through simulations and experiments.This UGV (Unmanned Ground Vehicle) is not only widely used in various practical applications but is also currently being researched in many disciplines. In particular, obstacle avoidance is considered one of the most important technologies in the navigation of an unmanned vehicle. In this paper, we introduce a simple algorithm for path planning in order to reach a destination while avoiding a polygonal-shaped static obstacle. To effectively avoid such an obstacle, a path planned near the obstacle is much shorter than a path planned far from the obstacle, on the condition that both paths guarantee that the robot will not collide with the obstacle. So, to generate a path near the obstacle, we have developed an algorithm that combines an edge detection method and a limit-cycle navigation method. The edge detection method, based on Hough Transform and IR sensors, finds an obstacle’ edge, and the limit-cycle navigation method generates a path that is smooth enough to reach a detected obstacle’ edge. And we proposed novel algorithm to solve local minima using the virtual wall in the local vision. Finally, we verify performances of the proposed algorithm through simulations and experiments.

Calculation of the Characteristic Limits for a Noble Gas Monitor Based on the ISO 11929 Publication

Chae-Hee Kim,Tae-Young Lee,Chang-Woo Seol,In-Su Chang 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.1

There are three questions arise in radioactivity measurements: (1) Dose the measured value originate from the radioactivity being present in the sample? (2) Is the measurement procedure suitable for the intended measurement purpose with respect to the requirements? (3) What is a range of values fairly sure our true value lies in with a specified probability? These three questions are answered by determining characteristic limits (decision threshold, detection limit and limits of the coverage interval), which are widely used as part of quality assurance in radioactivity measurements. In the past, numerous papers have focused on the questions in different ways, and have drawn a variety of conclusions about the meaning of the different characteristic limits using various terms and symbols. In recent years, substantial efforts were made in order to obtain a systematic and unified way to calculate and express these limits. As a result, the ISO 11929 Series which specify a procedure for calculation of the characteristic limits have been developed. This paper is focused on the calculations of characteristic limits for noble gas monitor (NGM204 monitor) that offers the continuous measurements of radioactive noble gases discharged from the stacks of the HANARO reactor facility. The calculations are based on the standard ISO 11929 as well as the traditional formulas provided by NUREG 1576, ANSI N42-18, ANSI N42-17 and DIN 25482. A comparison is made among the results obtained from the formulas given in each literature.

Refrigerant leakage detection in an EEV installed residential air conditioner with limited sensor installations

Yoo, Jin Woo,Hong, Sung Bin,Kim, Min Soo Elsevier 2017 International Journal of Refrigeration Vol.78 No.-

<P><B>Abstract</B></P> <P>Refrigerant leakage is the most frequently found fault in a refrigeration system and efficient detection is highly important. For a sudden leakage, it is relatively easy to detect but slow and long-term leakage is hard to find out, therefore, a useful method for leak detection in such condition is required. Large scale refrigeration systems have abundant data to detect or diagnose leakage. However, in case of small residential air conditioner, installed sensors are mostly temperature sensors, and the number of these sensors is also limited. In this study, a refrigerant leak detection method for an EEV (electronic expansion valve) installed residential air conditioners with limited sensor information is suggested based on experimental data. This method uses temperature differences between inlet air and midpoint of heat exchanger. For various temperature conditions, the temperature difference shows a similar trend which can be utilized as a good leak detection procedure.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Experiment of a residential air conditioner was conducted. </LI> <LI> Refrigerant leakage detection method is proposed with limited sensor installation. </LI> <LI> The detection charge level is between 52% and 62% at various temperature condition. </LI> </UL> </P>

Environmental Sciences : Development and Comparison of Analytical Methods for Measuring Simazine Herbicide Using Gas Chromatography/Ion Trap, Gas Chromatography/Mass Selective Detector, and High Performance Liquid Chromatography/Triple Quadrupole Mass Spe

( Ill-min Chung ),( In Myoung Park ),( Seung Hyun Kim ) 한국응용생명화학회(구 한국농화학회) 2011 Applied Biological Chemistry (Appl Biol Chem) Vol.54 No.5

Simazine is widely used to manage weed growth in the agricultural and industrial fields. Three analytical methods, including gas chromatography (GC)/ion-trap (IT), GC/mass selective detector (MSD), and high-performance liquid chromatography (HPLC)/triple quadrupole mass spectrometers (HPLC/MS/MS), were developed and compared for simazine quantification. The spike recoveries by GC/IT, GC/MSD, and HPLC/MS/MS were 100, 117, and 82.5%, respectively. Different spike recovery depending on analytical methods could be due to matrix effect, different instrumental sensitivity, losses during sample preparation or all of the above. The limit of detection was 0.0361, 0.0263, and 0.0013 mg/kg by GC/IT, GC/MSD, and HPLC/MS/MS, respectively. The HPLC/MS/MS with a positive atmospheric pressure chemical ionization (APCI) ionization mode was the most rapid (7 min), sensitive (limit of detection: 0.0013 mg/kg, limit of quantification: 0.0042 mg/kg), and precise (relative standard deviation: 0.5%) method for simazine quantification.

Development and Comparison of Analytical Methods for Measuring Simazine Herbicide Using Gas Chromatography/Ion Trap, Gas Chromatography/Mass Selective Detector, and High Performance Liquid Chromatography/Triple Quadrupole Mass Spectrometers

Chung, Ill-Min,Park, In-Myoung,Kim, Seung-Hyun The Korean Society for Applied Biological Chemistr 2011 Applied Biological Chemistry (Appl Biol Chem) Vol.54 No.5

Simazine is widely used to manage weed growth in the agricultural and industrial fields. Three analytical methods, including gas chromatography (GC)/ion-trap (IT), GC/mass selective detector (MSD), and high-performance liquid chromatography (HPLC)/triple quadrupole mass spectrometers (HPLC/MS/MS), were developed and compared for simazine quantification. The spike recoveries by GC/IT, GC/MSD, and HPLC/MS/MS were 100, 117, and 82.5%, respectively. Different spike recovery depending on analytical methods could be due to matrix effect, different instrumental sensitivity, losses during sample preparation or all of the above. The limit of detection was 0.0361, 0.0263, and 0.0013 mg/kg by GC/IT, GC/MSD, and HPLC/MS/MS, respectively. The HPLC/MS/MS with a positive atmospheric pressure chemical ionization (APCI) ionization mode was the most rapid (7 min), sensitive (limit of detection: 0.0013 mg/kg, limit of quantification: 0.0042 mg/kg), and precise (relative standard deviation: 0.5%) method for simazine quantification.

Development and Comparison of Analytical Methods for Measuring Simazine Herbicide Using Gas Chromatography/Ion Trap, Gas hromatography/Mass Selective Detector, and High Performance Liquid Chromatography/Triple Quadrupole Mass Spectrometers

정일민,박인명,김승현 한국응용생명화학회 2011 Applied Biological Chemistry (Appl Biol Chem) Vol.54 No.5

Simazine is widely used to manage weed growth in the agricultural and industrial fields. Three analytical methods, including gas chromatography (GC)/ion-trap (IT), GC/mass selective detector (MSD), and high-performance liquid chromatography (HPLC)/triple quadrupole mass spectrometers (HPLC/MS/MS), were developed and compared for simazine quantification. The spike recoveries by GC/IT, GC/MSD, and HPLC/MS/MS were 100, 117, and 82.5%, respectively. Different spike recovery depending on analytical methods could be due to matrix effect, different instrumental sensitivity, losses during sample preparation or all of the above. The limit of detection was 0.0361, 0.0263, and 0.0013 mg/kg by GC/IT, GC/MSD, and HPLC/MS/MS, respectively. The HPLC/MS/MS with a positive atmospheric pressure chemical ionization (APCI) ionization mode was the most rapid (7 min), sensitive (limit of detection: 0.0013 mg/kg, limit of quantification:0.0042 mg/kg), and precise (relative standard deviation: 0.5%) method for simazine quantification.

Highly sensitive and selective detection of Bis-phenol A based on hydroxyapatite decorated reduced graphene oxide nanocomposites

Alam, Mohammad K.,Rahman, Mohammed M.,Elzwawy, Amir,Torati, Sri Ramulu,Islam, Mohammad S.,Todo, Mitsugu,Asiri, Abdullah M.,Kim, Dojin,Kim, CheolGi Elsevier 2017 ELECTROCHIMICA ACTA Vol.241 No.-

<P><B>Abstract</B></P> <P>A facile and cost effective chemical reduction method is employed for the preparation of reduced graphene oxide/hydroxyapatite (rGO/HAp) nanocomposites. The transmission electron microscopy images revealed that the HAp flakes are well decorated on the surface of rGO. The morphological structure of the as-synthesized rGO/HAp nanocomposites was confirmed through X-ray diffraction, Fourier transform infrared spectroscopy and Raman spectroscopy, while the composition and thermal stability were analyzed by energy dispersive spectra and thermogravimetric analysis, respectively. Furthermore, the effect of rGO/HAp nanocomposites for the proliferation of Human Mesenchymal Stem Cell (hMSC) was performed to confirm the biocompatibility. A selective chemical sensor based on rGO/HAp modified glassy carbon electrode (GCE) for sensitive detection of Bis-phenol A (BPA) has been developed. Several important parameters controlling the performance of the BPA chemi-sensor were investigated and optimized at room conditions. The rGO/HAp/Nafion/GCE sensor offers a fast response and highly sensitive BPA detection. Under the optimal conditions, a linear range from 0.2nmolL<SUP>−1</SUP> to 2.0mmolL<SUP>−1</SUP> for the detection of BPA was observed with the detection limit of 60.0pmolL<SUP>−1</SUP> (signal-to-noise ratio, at an SNR of 3) and sensitivity of 18.98×10<SUP>4</SUP> μA.L/μmol.m<SUP>2</SUP>. Meanwhile, the fabricated chemi-sensor showed an excellent, specific and selective recognition to target BPA molecules among coexistence of other analytes in the buffer system. This novel effort initiated a well-organized way of efficient rGO/HAp/Nafion/GCE sensor development and practically analyzed the real hazardous environmental pollutants at room conditions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Simple chemical reduction method was used for preparation of reduced graphene oxide/hydroxyapatite (rGO/HAp) nanocomposites. </LI> <LI> The rGO/HAp nanocomposites exhibited good biocompatibility with hMSCs. </LI> <LI> Selective chemical sensor based on rGO/HAp nanocomposites was developed for detection of Bis-phenol A. </LI> <LI> The fabricated rGO/HAp/Nafion/GCE sensor exhibited good detection limit of 60pmolL<SUP>−1</SUP>. </LI> </UL> </P>

Evaluation of Various Real-Time Reverse Transcription Quantitative PCR Assays for Norovirus Detection

( Ju Eun Yoo ),( Cheonghoon Lee ),( Sungjun Park ),( Gwangpyo Ko ) 한국미생물 · 생명공학회 2017 Journal of microbiology and biotechnology Vol.27 No.4

Human noroviruses are widespread and contagious viruses causing nonbacterial gastroenteritis. Real-time reverse transcription quantitative PCR (real-time RT-qPCR) is currently the gold standard for the sensitive and accurate detection of these pathogens and serves as a critical tool in outbreak prevention and control. Different surveillance teams, however, may use different assays, and variability in specimen conditions may lead to disagreement in results. Furthermore, the norovirus genome is highly variable and continuously evolving. These issues necessitate the re-examination of the real-time RT-qPCR`s robustness in the context of accurate detection as well as the investigation of practical strategies to enhance assay performance. Four widely referenced real-time RT-qPCR assays (Assays A-D) were simultaneously performed to evaluate characteristics such as PCR efficiency, detection limit, and sensitivity and specificity with RT-PCR, and to assess the most accurate method for detecting norovirus genogroups I and II. Overall, Assay D was evaluated to be the most precise and accurate assay in this study. A ZEN internal quencher, which decreases nonspecific fluorescence during the PCR, was added to Assay D`s probe, which further improved the assay performance. This study compared several detection assays for noroviruses, and an improvement strategy based on such comparisons provided useful characterizations of a highly optimized real-time RT-qPCR assay for norovirus detection.

Anomaly Detection of Network Traffic Based on Prediction and Self-Adaptive Threshold

Haiyan Wang 보안공학연구지원센터 2015 International Journal of Future Generation Communi Vol.8 No.6

Security problems with network are significant, such as network failures and malicious attacks. Monitoring network traffic and detect anomalies of network traffic is one of the effective manner to ensure network security. In this paper, we propose a hybrid method for network traffic prediction and anomaly detection. Specifically, the original network traffic data is decomposed into high-frequency components and low-frequency components. Then, non-linear model Relevance Vector Machine (RVM) model and ARMA (Auto Regressive Moving Average) model are employed respectively for prediction. After combining the prediction, a self-adaptive threshold method based on Central Limit Theorem (LCT) is introduced for anomaly detection. Moreover, our extensive experiments evaluate the efficiency of proposed method.