Comparative Study of Dry Storage Condition Characteristics of HANA and Commercial Cladding

Yongsik Yang,Jaeyong Kim,Jongdae Hong,Jangsoo Oh,Juyeop Park 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.2

In nuclear fuel development research, consideration of the back-end cycle is essential. In particular, a review of an in-reactor performance of nuclear fuel related to the various degradation phenomena that can occur during spent fuel dry storage is an important area. The important factors affecting the degradation of zirconium-based cladding during dry storage are the cladding’s hydrogen concentration and rod internal pressure after irradiation. In this study, a preliminary analysis of the in-reactor behavior of the HANA cladding, which has been developed and is currently undergoing licensing review, was performed, and based on this result, a comparative analysis between nuclear fuel with HANA cladding and current commercial fuel under storage conditions was performed. The results show that the rod internal pressure of nuclear fuel with HANA cladding is not significantly different from that of commercial cladding, and the hydrogen concentration in the cladding tends to reduce due to the increased corrosion resistance, so fuel integrity in a dry storage conditions is not expected to be a major problem. Although the lack of cladding creep data under dry storage conditions, the results from the Halden research reactor test comparing in-reactor creep behavior with Zircaloy-4 showed that there is sufficient margin for degradation due to creep during storage.

Suggestion of Simple Rod Internal Pressure and Free Void Volume Correlations in Spent Fuel Rod

Yongsik Yang,Donghak Kook 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.2

A rod internal pressure increased by fission gas release is major factor that causes degradation during dry storage of spent fuel. Because rod internal pressure is greatly affected by fuel design, operation power history, it is essential to perform complex calculation using performance code to accurately predict rod internal pressure as function of burnup. However, because it is difficult to apply a complex method into dry storage design and to determine rod internal pressure based on conservative way this study presents a simple correlation that can predict an approximate rod internal pressure as function of burnup For the development of simple correlation, rod internal pressure and fuel rod void volume data measured through about 400 PIE (Post Irradiation Examination) data were used. The developed simple correlation can cover various fuel rod arrays, discharged fuel average burnup, operation history, cladding type, burnup range, and information on Westinghouse type fuel rods such as Spain ENUSA, USA EPRI/ANL/ORNL/PNNL, WEC, etc. In this paper, the data of simple correlation determination is briefly introduced, and the data analysis process and results are summarized. Two correlations that can conservatively determine rod internal pressure and free void volume in fuel rod according to fuel rod average burnup were presented, and the effect of initial He fill pressure was evaluated. In particular, the results of Post Irradiation Examination for 46 fuel rods conducted in Korea are also included, so it is expected that newly presented correlations can be used easily in various ways in the domestic research, industry, and academia.

A Sub-100 <tex> $\mu{\rm W}$</tex> Ku-Band RTD VCO for Extremely Low Power Applications

Yongsik Jeong,Sunkyu Choi,Kyounghoon Yang IEEE 2009 IEEE microwave and wireless components letters Vol.19 No.9

<P>This letter presents the microwave performance of a sub-100 ¿W Ku-band differential-mode resonant tunneling diode (RTD)-based voltage controlled oscillator (VCO) with an extremely low power consumption of 87 ¿W using an InP-based RTD/HBT MMIC technology. In order to achieve the extremely low-power Ku-band RTD VCO, the device size of RTD is scaled down to 0.6 × 0.6 ¿m<SUP>2</SUP>. The obtained dc power consumption of 87 ¿W is found to be only 1/18 of the conventional-type MMIC VCOs reported in the Ku-band. The fabricated RTD VCO has a phase noise of -100.3 dBc/Hz at 1 MHz offset frequency and a tuning range of 140 MHz with the figure-of-merit (FOM) of -194.3 dBc/Hz.</P>

Parallel Block Sequential Closed-Form Matting With Fan-Shaped Partitions

Lee, Yongsik,Yang, Seungjoon IEEE 2018 IEEE TRANSACTIONS ON IMAGE PROCESSING - Vol.27 No.2

<P>Applying alpha matting to large images is a challenging task because of its computational complexity. This paper provides a divide and conquer strategy for performing closed-form matting. The matting problem, defined for an entire image, is broken down into systems of linear equations defined for very small blocks of the image. The sizes of the small systems are small enough for us to find solutions efficiently using a direct sparse linear equation system solver. The small systems are solved following a sequential order such that the alpha matte grows from a user scribble. With the block sequential application, matting is performed on fan-shaped partitions in parallel on multiple processing cores. Experiments on large test images as well as on standard benchmark test images show that the proposed parallel block sequential matting provides high quality alpha mattes with good scalability.</P>

Proposal of Post-Processing Method for Ring Tensile Test Results for Relative Comparison of Young’s Modulus of Materials

JaeYong Kim,YongSik Yang,JuYeop Park 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.2

Ring Tensile Test (RTT) is mainly performed for comparing tensile strength and total strain between nuclear fuel cladding specimens under various initial conditions. Through RTT, the loaddisplacement (F-D) curve obtained from the uniaxial tensile test can also be obtained. However, the Young’s modulus estimated from the gradient of the straight portion is much lower than general value of materials. The reasons include tensile machine compliance, slack in the fixtures, or elastic deformation of the fixtures and the tooling. Another reason is that the bending of the test part in the ring is stretched with two pieces of tools. Although the absolute value of the Young’s modulus is smaller than the actual value, it is applicable to calculate the ratio of the Young’s moduli of different materials, that is, the relative value. The Young’s modulus, or slope of the linear section, varies slightly depending on which location data is used and how much data is included. In order to obtain a more accurate ratio of Young’s moduli between materials using the RTT results, a post-processing method for the ring tensile test results that can prevent such human errors is proposed as follows. First, the slope of the linear section is obtained using the displacement and load when the load increase is the largest and the displacement and load of the position that is 95% of the maximum load increase. To replace the section where the ring-shaped specimen is stretched at the beginning of the F-D curve, a straight line equal to the slope of the linear section is drawn to the displacement axis from the position of maximum load increase and moved to the origin to obtain the final F-D curve for a RTT. Lastly, the yield stress uses the stress at the point where the 0.2% offset straight line and the F-D curve meet as suggested in the ASTM E8/E8M-11 “Standard test methods for tensile testing of metallic materials”. RTT results post-processing method was coded using FORTRAN language so that it could be performed automatically. In addition, sensitivity analysis of the included data range on the Young’s modulus was performed by using the included data range as 90%, 85%, and 80% of the maximum load increase.

전국(소년)체육대회의 개선 방안으로서 초 · 중 · 고 통합 학생체육대회에 대한 인식

양종현(Jonghyun Yang),박정준(Jeongjun Park),이용식(Yongsik Lee) 한국스포츠교육학회 2020 한국스포츠교육학회지 Vol.27 No.1

이 연구는 전국(소년)체육대회의 개선 방안으로서, 초 · 중 · 고등학생을 통합 관리할 수 있는 학생체육대회로의 전환에 대한 인식을 탐색하는 것을 목적으로 한다. 이를 위해 전국 17개 시도의 일반인 423명, 체육 및 스포츠 전문가 1,895명을 대상으로 설문조사를 하였고, 통계적 분석을 통해 다음과 같은 결과 및 논의점을 도출하였다. 첫째, 우수 선수 발굴을 통해 국내 · 국제 대회에서 국위선양을 하는 것도 중요하지만, 선수 훈련의 공정성 및 대회 참여에 따른 교육적 가치가 보다 강조되어야 한다. 둘째, 고등부를 전국체육대회에서 분리하여 초 · 중등부와 통합하는 것에 대한 전문가 집단의 찬성과 반대 의견 비율은 비슷하였으나, 2010년의 조사결과와 비교할 때 통합 의견 비율이 4배 이상 증가하였으며(10.3% → 44.5%), 전문가 집단 내 경기 및 대회 관계자 집단과 교육(행정) 관계자 집단 간의 인식 차이가 명확하게 나타났다. 셋째, 초 · 중 · 고등학교 통합 학생체육대회는 학생들의 학습권 보장에는 긍정적이지만, 엘리트 선수 육성 침체 및 교육부 관리의 한계 등 예상되는 난점을 극복하기 위해 문화체육관광부와 대한체육회의 지속적인 지원이 필요하다. 결론적으로 초 · 중 · 고 통합 학생체육대회로의 전환은 ‘학생선수의 통합’, ‘학생선수와 일반학생의 통합’, ‘학습과 선수활동의 통합’이 전제가 되어야 한다. The purpose of this study was to investigate the awareness of transition of national sports competitions to a student sports competition that can be managed by elementary, middle and high school students in a unified way. To this end, 423 ordinary people and 1,895 sports experts from 17 cities and provinces nationwide were surveyed, and the following results and discussion points were derived through statistical analysis. First, it is important to promote national prestige in domestic and international competitions through the excavation of outstanding athletes, but the fairness of the training of athletes and the educational value of participating in the competition must be emphasized more. Second, the approval and opposition ratios of the expert groups on separating high schools from the primary and secondary branches were similar, but compared to the 2010 findings, the combined opinion ratio more than quadrupled (10.3% → 44.5%) and the difference in perception between the competition and competition officials within the expert group and the educational(administration) officials groups was evident. Third, the integrated student sports competition for elementary, middle and high schools is positive about guaranteeing students" right to study, but it needs continued support from the Ministry of Culture, Sports and Tourism and the Korea Sports Council to overcome expected difficulties, such as the slump in the promotion of elite athletes and the limitations of the education ministry"s management. In conclusion, the transition to integrated student sports competitions in elementary, middle and high schools should be the premise of "integration of student athletes", "integration of student athletes and ordinary students" and "integration of learning and activities".

Applicability Evaluation of Ramberg-Osgood Equation as New Cladding Plastic Material Model

JaeYong Kim,YongSik Yang,JuYeop Park 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.2

For the spent fuel modeling, the plastic model of the cladding used in FRAPCON uses the σ? = K??? ? ?? ????? ? format. Strength coefficient (K), strain hardening exponent (n), strain rate sensitivity constant (m) are derived as the function of temperature. The coefficient m related to the strain rate shows dependence on the strain rate only in the α-β phase transition section, 1,172.5~1,255 K. But this is the analysis range of the FRAPTRAN code, which is an accident condition nuclear fuel behavior evaluation code. It does not apply to evaluate spent fuel. This coefficient in FRAPCON is used as a constant value (0.015) below 750 K (476.85°C), and at a temperature above 750 K, it is assumed that it is linearly proportional to the temperature without considering the strain rate dependence, also. In order to confirm the effect of strain rate, multiple test data performed under various conditions are required. However, since the strain rate dependence is not critical and test specimen limitation in the case of spent fuel, it is needed to replace with a new plastic model that does not include the strain rate term. In the new plastic model, the basic form of the Ramberg-Osgood equation (RO equation) is the same as ε? = ?? ? + ?? ??? ?? ??. If the new variable α is defined as α = ?????/??????, this equation can be transformed into ε? = ?? ? + ? ?? ? ? ?? ?? ? ???? . The procedure for expressing the stress-strain curve of the cladding with the RO equation is as follows. First, convert the engineering stress-strain into true stress-strain. Second, using a data analysis program such as EXCEL or ORIGIN, obtain the slope of the linear trend-line on the linear part and use it as the elastic modulus. Third, using the 0.2% offset method, find the yield point and the yield stress. Finally, using the solver function of EXCEL, find the optimal values of α and ?? that minimize the sum of errors. The applicability of the suggested RO equation was evaluated using the results of the Zircaloy-4 plate room temperature tensile test performed by the KAERI and the Zircaloy cladding uniaxial tensile test results presented in the PNNL report. Through this, the RO equation was able to express the tensile test results within the uncertainty range of ±0.005. In this paper, the RO equation is suggested as a new plastic model with limited test data due to the test specimen limitation of spent fuel and its applicability is confirmed.

A Novel High-Speed Multiplexing IC Based on Resonant Tunneling Diodes

Sunkyu Choi,Yongsik Jeong,Jongwon Lee,Kyounghoon Yang IEEE 2009 IEEE TRANSACTIONS ON NANOTECHNOLOGY Vol.8 No.4

<P>A new multiplexing IC based on the resonant tunneling diode (RTD) is proposed. The unique negative differential resistance characteristics arising from quantum effects of the RTD enable us to develop a new functional low-power digital circuit. The proposed multiplexing IC consists of two current-mode-logic monostable-bistable transition logic elements (CML-MOBILEs) based on the RTD and a low-power selector circuit block. The proposed circuit has been fabricated by using an InP RTD/ heterojunction bipolar transistor monolithic microwave integrated circuit technology. The multiplexing operation of the fabricated quantum effect IC has been confirmed up to 45 Gb/s for the first time as a monolithic technology based on the quantum effect devices. The dc power consumption is only 23 mW, which is found to be one-fourth of the current state-of-the-art conventional transistor-based multiplexing IC.</P>

Process Optimization for High Frequency Performance of InP-Based Heterojunction Bipolar Transistors

Yongjoo Song,Yongsik Jeong,Kyounghoon Yang 대한전자공학회 2003 Journal of semiconductor technology and science Vol.3 No.1

국내 원자로 상부헤드관통관 기량검증 기술개발

김용식,윤병식,양승한,Kim, Yongsik,Yoon, Byungsik,Yang, Seunghan 한국압력기기공학회 2014 한국압력기기공학회 논문집 Vol.10 No.1

There were many flaw issues of reactor vessel head penetration in USA fleets. USNRC issued 10CFR50.55a to implement reactor vessel head penetration ultrasonic examination performance demonstration(PD) in US for enhancement of inspection reliability. After September 2009, all US utilities inspected their RVHP with PD qualified system. Korea Hydro and Nuclear Power Company(KHNP) have developed reactor vessel head penetration performance demonstration system for ultrasonic test to apply for pressurized light-water reactor power plants in accordance with 10CFR50.55a since September 2011. RVHP configuration surveying and analysis, code requirement analysis, and performance demonstration specimen design were performed up to this day. Fingerprinting of manufactured specimen, development of test data management program, development of operation procedure, input of flawed data, and development of final report will be performed for the next step. This paper describes the development status of the performance demonstration system for reactor vessel head penetration ultrasonic examination in Korea.