Radioactivity Characteristics and Safety Management of Steel Scarp

Yeoungsuk Go,Eun Lee,Suk K. Sim,Sun Dong Ju,Sang-uk Oh 한국방사성폐기물학회 2017 한국방사성폐기물학회 학술논문요약집 Vol.2017 No.10

Local Characteristics of Two-Phase Flow Parameters in an Annulus Boiling Channel

Byong Jo Yun,Suk K.Sim,Su Hyun Hwang,Goon Cherl Park 대한기계학회 1997 KSME International Journal Vol.11 No.4

A Generalized Model for the Prediction of Thermally-Induced CANDU Fuel Element Bowing

석호천,심기섭,박주환,Suk, H.C.,Sim, K-S.,Park, J.H. Korean Nuclear Society 1995 Nuclear Engineering and Technology Vol.27 No.6

The CANDU element bowing is attributed to actions of both the thermally induced bending moments and the bending moment due to hydraulic drag and mechanical loads, where the bowing is defined as the lateral deflection of an element from the axial centerline. This paper consider only the thermally-induced bending moments which are generated both within the sheath and the fuel and sheath by an asymmetric temperature distribution with respect to the axis of an element The generalized and explicit analytical formula for the thermally-induced bending is presented in con-sideration of 1) bending of an empty tube treated by neglecting the fuel/sheath mechanical interaction and 2) fuel/sheath interaction due to the pellet and sheath temperature variations, where in each case the temperature asymmetries in sheath are modelled to be caused by the combined effects of (i) non-uniform coolant temperature due to imperfect coolant mixing, (ii) variable sheath/coolant heat transfer coefficient, (iii) asymmetric heat generation due to neutron flux gradients across an element and so as to inclusively cover the uniform temperature distributions within the fuel and sheath with respect to the axial centerline. As the results of the sensitivity calculations of the element bowing with the variations of the parameters in the formula, it is found that the element bowing is greatly affected relatively with the variations or changes of element length, sheath inside diameter, average coolant temperature and its variation factor, pellet/sheath mechanical interaction factor, neutron flux depression factor, pellet thermal expansion coefficient, pellet/sheath heat transfer coefficient in comparison with those of other parameters such as sheath thickness, film heat transfer coefficient, sheath thermal expansion coefficient and sheath and pellet thermal conductivities. CANDU 핵연료봉의 휨 열적 휨 멘트와 수력학적 견인력 및 기계적 하중에 기인하는 휨 모멘트에 의하여 일어난다. 여기서, 연료봉 휨은 연료봉 축방향 중심선으로부터의 측면 처짐으로 정의한다. 본 논문에서는 연료봉 축방향 중심선에 대한 비대칭 온도불포에 의해 핵연료 피복관 자체와 피복관과 소결체의 상호작용 부위에서 발생하는 열적 휨만을 취급한다. 이를 위해 1).소결체와 피복관사이의 기계적 상호작용을 무시한 조건에서의 핵연료 피복관의 휨과 2) 소결체와 피복관의 온도 변화에 기인하여 발생하는 소결체와 피복관 사이의 기계적 상호작용을 고려한 조건에서의 연료봉 휨을 혼합 고려하고, 각각에서 피복관의 비대칭 온도분포가 (i) 냉각재의 불완전한 혼합에 따른 비균질 냉각재 온도, (ii) 핵연료 피복관과 냉각재 사이의 비균질한 열전달 계수, (iii) 핵연료내 반경 방향으로의 중성자속 감쇄에 의한 비대칭 열 발생 등의 복합적효과에 의해 발생되는 것으로 고려하여 피복관의 대칭온도 분포까지 포함 할 수 있는 열적 휨의 일반적 해석 공식을 제시하였다. 본 휨 공식에 사용되는 모든 변수에 대한 민감도 분석을 통해, 핵연료봉 길이, 피복관 내경, 냉각재 평균 온도 및 변화 인자, 소결체 -피복관 기계적 상호 작용 인자, 중성자속 감쇄 인자, 핵연료 열팽창 계수, 피복관-냉각재 열전도 계수 등의 변화가 피복관 두께, 피복관-냉각재 열전달 계수, 피복관 열팽창 계수, 핵연료-피복관 열전달 계수 등의 변화보다 핵연료봉의 열적 휨에 상대적으로 더욱 영향을 미치는 것으로 밝혀졌다.

FIRST ATLAS DOMESTIC STANDARD PROBLEM (DSP-01)FOR THE CODE ASSESSMENT

김연식,최기용,강경호,박현식,조석,백원필,김경두,SUK K. SIM,EO-HWAK LEE,SEYUN KIM,김주성,TONG-SOO CHOI,CHEOL-WOO KIM,SUK-HO LEE,SANG-IL LEE,KEO HYOUNG LEE 한국원자력학회 2011 Nuclear Engineering and Technology Vol.43 No.1

KAERI has been operating an integral effect test facility, ATLAS (Advanced Thermal-Hydraulic Test Loop for AccidentSimulation), for accident simulations of advanced PWRs. Regarding integral effect tests, a database for major design basisaccidents has been accumulated and a Domestic Standard Problem (DSP) exercise using the ATLAS has been proposed andsuccessfully performed. The ATLAS DSP aims at the effective utilization of an integral effect database obtained from theATLAS, the establishment of a cooperative framework in the domestic nuclear industry, better understanding of thermalhydraulic phenomena, and an investigation of the potential limitations of the existing best-estimate safety analysis codes. Forthe first ATLAS DSP exercise (DSP-01), integral effect test data for a 100% DVI line break accident of the APR1400 wasselected by considering its technical importance and by incorporating comments from participants. Twelve domesticorganizations joined in this DSP-01 exercise. Finally, ten of these organizations submitted their calculation results. ThisATLAS DSP-01 exercise progressed as an open calculation; the integral effect test data was delivered to the participantsprior to the code calculations. The MARS-KS was favored by most participants but the RELAP5/MOD3.3 code was alsoused by a few participants. This paper presents all the information of the DSP-01 exercise as well as the comparison resultsbetween the calculations and the test data. Lessons learned from the first DSP-01 are presented and recommendations forcode users as well as for developers are suggested.

Oxidation Behavior and Microstructural Evolution of Graphite Substrates with SiC and Si3N4 Coatings Prepared by Using a Solid-Vapor Reaction

Jeong-Pyo Kim,Sung-Il Jung,Young-Suk Sim,백운규,Vijay K. Srivastava,Shraddha Singh,Akash Mohanty,정연길 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.54 No.3

The oxidation behavior of graphite substrates with silicon carbide (SiC) and silicon nitride (Si3N4) coatings, prepared by using a solid-vapor reaction process, was investigated in cyclic oxidation tests. The effect of the porosity of the substrate on the oxidation behavior was also investigated. Substrates with the SiC coating showed higher weight loss than those with the Si3N4 coating. Oxidation of the substrates with 10 and 13 % porosities with the Si3N4 coating took place at 900℃ and at 1000℃, respectively. However, after long term cyclic oxidation tests, the substrate with 13 % porosity with the Si3N4 coating was oxidized at a relatively low temperature of 800℃, even though the weight loss was below 10 %. In the case of the SiC coatings, detachment of the coating region or full oxidation of the substrates took place whereas in the case of the Si3N4 coatings, no evidence of delamination or detachment of the coating region was observed after oxidation. The oxidation was affected by the coating thickness and by the type of materials coated on the substrate, not by the porosity of the substrate itself, although the coating thickness did depend on the porosity of the substrate.

Proposed Regulatory Standards for the Industrial NORM Waste Management

Yeoungsuk Go,Eun Lee,Jaeman Kim,Suk K. Sim 한국방사성폐기물학회 2018 한국방사성폐기물학회 학술논문요약집 Vol.2018 No.05

FIRST ATLAS DOMESTIC STANDARD PROBLEM (DSP-01) FOR THE CODE ASSESSMENT

Kim, Yeon-Sik,Choi, Ki-Yong,Kang, Kyoung-Ho,Park, Hyun-Sik,Cho, Seok,Baek, Won-Pil,Kim, Kyung-Doo,Sim, Suk-K.,Lee, Eo-Hwak,Kim, Se-Yun,Kim, Joo-Sung,Choi, Tong-Soo,Kim, Cheol-Woo,Lee, Suk-Ho,Lee, Sang Korean Nuclear Society 2011 Nuclear Engineering and Technology Vol.43 No.1

KAERI has been operating an integral effect test facility, ATLAS (Advanced Thermal-Hydraulic Test Loop for Accident Simulation), for accident simulations of advanced PWRs. Regarding integral effect tests, a database for major design basis accidents has been accumulated and a Domestic Standard Problem (DSP) exercise using the ATLAS has been proposed and successfully performed. The ATLAS DSP aims at the effective utilization of an integral effect database obtained from the ATLAS, the establishment of a cooperative framework in the domestic nuclear industry, better understanding of thermal hydraulic phenomena, and an investigation of the potential limitations of the existing best-estimate safety analysis codes. For the first ATLAS DSP exercise (DSP-01), integral effect test data for a 100% DVI line break accident of the APR1400 was selected by considering its technical importance and by incorporating comments from participants. Twelve domestic organizations joined in this DSP-01 exercise. Finally, ten of these organizations submitted their calculation results. This ATLAS DSP-01 exercise progressed as an open calculation; the integral effect test data was delivered to the participants prior to the code calculations. The MARS-KS was favored by most participants but the RELAP5/MOD3.3 code was also used by a few participants. This paper presents all the information of the DSP-01 exercise as well as the comparison results between the calculations and the test data. Lessons learned from the first DSP-01 are presented and recommendations for code users as well as for developers are suggested.

Improvement of Liquid Droplet Entrainment Model in the COBRA-TF Code

Ha, K.-S 한국원자력학회 1998 Nuclear Engineering and Technology Vol.30 No.3