STRAIN-BASED PLASTIC INSTABILITY ACCEPTANCE CRITERIA FOR FERRITIC STEEL SAFETY CLASS 1 NUCLEAR COMPONENTS UNDER LEVEL D SERVICE LOADS

Ji-Su Kim,HAN-SANG LEE,김종성,김윤재,김진원 한국원자력학회 2015 Nuclear Engineering and Technology Vol.47 No.3

This paper proposes strain-based acceptance criteria for assessing plastic instability of the safety class 1 nuclear components made of ferritic steel during level D service loads. The strain-based criteria were proposed with two approaches: (1) a section average approach and (2) a critical location approach. Both approaches were based on the damage initiation point corresponding to the maximum load-carrying capability point instead of the fracture point via tensile tests and finite element analysis (FEA) for the notched specimen under uni-axial tensile loading. The two proposed criteria were reviewed from the viewpoint of design practice and philosophy to select a more appropriate criterion. As a result of the review, it was found that the section average approach is more appropriate than the critical location approach from the viewpoint of design practice and philosophy. Finally, the criterion based on the section average approach was applied to a simplified reactor pressure vessel (RPV) outlet nozzle subject to SSE loads. The application shows that the strain-based acceptance criteria can consider cumulative damages caused by the sequential loads unlike the stress-based acceptance criteria and can reduce the overconservatism of the stress-based acceptance criteria, which often occurs for level D service loads.

Three-dimensional dose reconstruction-based pretreatment dosimetric verification in volumetric modulated arc therapy for prostate cancer

Yuri Jeong,Jeong Geun Oh,Jeong Ku Kang,Sun Rock Moon,Kang Kyoo Lee 대한방사선종양학회 2020 Radiation Oncology Journal Vol.38 No.1

Purpose: We performed three-dimensional (3D) dose reconstruction-based pretreatment verification to evaluate gamma analysis acceptance criteria in volumetric modulated arc therapy (VMAT) for prostate cancer. Materials and Methods: Pretreatment verification for 28 VMAT plans for prostate cancer was performed using the COMPASS system with a dolphin detector. The 3D reconstructed dose distribution of the treatment planning system calculation (TC) was compared with that of COMPASS independent calculation (CC) and COMPASS reconstruction from the dolphin detector measurement (CR). Gamma results (gamma failure rate and average gamma value [GFR and γAvg]) and dose-volume histogram (DVH) deviations, 98%, 2% and mean dose-volume difference (DD98%, DD2% and DDmean), were evaluated. Gamma analyses were performed with two acceptance criteria, 2%/2 mm and 3%/3 mm. Results: The GFR in 2%/2 mm criteria were less than 8%, and those in 3%/3 mm criteria were less than 1% for all structures in comparisons between TC, CC, and CR. In the comparison between TC and CR, GFR and γAvg in 2%/2 mm criteria were significantly higher than those in 3%/3 mm criteria. The DVH deviations were within 2%, except for DDmean (%) for rectum and bladder. Conclusions: The 3%/3 mm criteria were not strict enough to identify any discrepancies between planned and measured doses, and DVH deviations were less than 2% in most parameters. Therefore, gamma criteria of 2%/2 mm and DVH related parameters could be a useful tool for pretreatment verification for VMAT in prostate cancer.

APR1400 원자로내부구조물 종합진동평가 응답측정시험 허용기준 수립

고도영(Do-Young Ko),김규형(Kyu-Hyung Kim),김성환(Sung-Hwan Kim) 한국소음진동공학회 2011 한국소음진동공학회 학술대회논문집 Vol.2011 No.10

APR1400 RVI CVAP using the non-prototype category is being conducted to verify integrity of the RVI design and to secure the CVAP technology. The measurement programs are to confirm vibration analysis results for reactor internals during preoperational and initial startup testing and to detemine the safety margin. One of the important basis for the measurement programs is test acceptance criteria. Therefore, this paper is on establishment of response instrumentation test acceptance criteria for APR1400 RVI CVAP. The established acceptance criteria show that the stress criteria of APR1400 RVI are more conservative values than those of the valid prototype plant(Palo Verde unit 1) and, the displacement criteria of the IBA and the UGS were established to 0.03 in and 0.01 in, respectively.

APR1400 원자로내부구조물 종합진동평가 응답측정시험 허용기준

고도영(Ko, Do-Young),김규형(Kim, Kyu-Hyung),김성환(Kim, Sung-Hwan) 한국소음진동공학회 2011 한국소음진동공학회 논문집 Vol.21 No.11

APR1400 RVI CVAP using the non-prototype category II is being conducted to verify integrity of the RVI design and to secure the CVAP technology. The measurement programs are to confirm vibration analysis results for reactor internals during pre-operational and initial startup testing and to determine the safety margin. One of the important basis for the measurement programs is test acceptance criteria. Therefore, this paper is on establishment of response instrumentation test acceptance criteria for APR1400 RVI CVAP. The established acceptance criteria show that the stress criteria of APR1400 RVI are more conservative values than those of the valid prototype plant(Palo Verde unit 1) and, the displacement criteria of the inner barrel assembly and the upper guide structure were established to 0.03 in and 0.01 in, respectively.

자체완성적 신고와 행정요건적 신고의 구분

류광해(Ryu, Kwang-Hae) 조선대학교 법학연구원 2013 法學論叢 Vol.20 No.1

There are several arguing points about ‘the Report(or Statement) in administrative law’. In this paper, I researched whether the classification of ‘the Report without Acception’ and ‘the Report in need of Acception’ is needed or not, and what are the classification criteria when it is needed. There is an opinion that the classification of ‘the Report without Acception’ and ‘the Report in need of Acception’ is not needed. But I think the classification is needed, because there are differences between the German laws and the Korean laws, the above opinion has a logical problem when the Report is illegal, and the administrative and judicial practices affirm adamantly the classification. On the classification criteria, I think, those cannot be the classification criteria, whether report and registration is prescribed simultaneously in the same statute, whether there is needed not only formal requisites but also substantial requisites when a person presents administive report, and whether an administrator can examine formally or substantially. I think those can be classification criteria, whether the statute needs obviously the administrator's acception about report, whether the purpose of a report is only information collection, and whether, in case that the report can remove legal prohibition, the removing of legal prohibition can affect largely the national securities, public orders and public welfare, or not. 행정법상 신고에는 처분성의 문제, 심사범위의 문제, 신고의 구분 필요성과 구분기준의 문제, 적법한 신고의 효력발생시기 문제, 부적법한 신고의 효력 문제 등 수많은 쟁점들이 있다. 여기서는 이러한 여러 쟁점 중에서 신고를 자체완성적 신고와 행정요건적 신고로 구분할 필요성이 있는지 여부, 구분할 필요성이 있다면 그 구분기준은 어떠해야 하는지 여부에 대하여 살펴보았다. 행정법상 신고를 자체완성적 신고와 행정요건적 신고로 나눌 필요성이 없다는 견해도 있으나 우리 법제와 독일 법제의 차이, 부적법한 신고의 논리 구성상의 문제, 견고한 실무상의 태도 등을 종합할 때 그 구분 필요성을 부인하는 것은 현실성이 없다고 생각된다. 그 구분기준으로는 신고와 등록이 구분되어 규정되어 있는지 여부, 형식적 요건, 실질적 요건, 형식적 심사, 실질적 심사가 어떠한지 여부 등이 될 수 없고, 법령상 수리를 요하는 것이 명백하다면 행정요건적 신고, 신고의 취지가 정보제공적이어서 최소한의 규제를 요할 경우에는 자체완성적 신고라고 할 것이고, 금지해제적 신고의 경우 국가의 안전보장, 질서유지, 공공복리에 미치는 영향이 큰지 여부에 대한 이익형량을 통해 자체완성적 신고와 행정요건적 신고는 구분하는 것이 헌법이나 금지의 취지에 비추어 타당하다고 생각된다. 이 때 국가의 안전보장, 질서유지, 공공복리의 구체적 내용은 개별 법령에 따라 구체화하면 될 것이다.

교통수요 분석의 도로교통량 정산결과 검증기준 연구 - 지역간/광역권/도시부 교통류를 사례로 -

성홍모,장수은,김찬성 한국교통연구원 2009 交通硏究 Vol.16 No.2

Comparison of observed traffic counts and the modelled traffic counts from the base-year traffic assignment model is important. The standard validation manual from US and UK suggests validation target guidelines considering various traffic stream characteristics. But, in Korea, standard criteria of the targets ranges to validate traffic volume has not been developed. There is a simple rule to validate traffic counts. In this study, we suggests an acceptable validation standard of traffic volumes in the travel demand analysis in consideration of traffic stream characteristics according to intercity/metropolitan/urban traffics. The data used for this study is real data provided by Seoul city, Korea Institute of Construction Technology and Korea Expressway Corporation. As a result through the analysis, we found that traffic volumes by traffic stream characteristics, area type and volume group could be used to develop new validation standard criteria. Finally, this study proposes that further researches about an acceptable validation standard of mass transportation as well as volumes, speed and vehicle kilometers traveled(VMT) be required. 수요추정 과정에서 교통량 정산은 배정 교통량과 관측 교통량을 비교하여 모형의 현실 모사능력을 평가하는 단계이다. 정산의 정확도는 장래 교통수요 추정 결과에 매우 큰 영향을 미치므로, 통상적 교통수요 분석과정에서 세심한 주의를 요하는 부분이다. 그런데 정산의 기준이 되는 관측 교통량은 계절, 통행권역, 교통량 수준, 도로의 기능 등 여러 변동요인에 노출되어 있다. 그러나 국내 수요분석 표준지침에서는 이러한 특성을 고려하지 않고 일괄적으로 관측 교통량 대비 10~30% 기준을 적용하고 있다. 본 연구의 목적은 도로교통량의 불확실성을 고려한 정산단계의 합리적 오차허용기준을 정립하는데 있다. 이에 본 연구에서는 도로교통량 정산결과 검증기준 산정안을 개발하여 적용가능성을 타진해 보았다. 그 결과 기존 가이드라인과 차별성을 지닌 교통량 수준별 검증기준을 도출할 수 있었다. 다만, 관련 자료 부재로 도시부 연속류에 대한 분석이 이루어지지 않았으므로, 향후 추가 연구가 수행되어야 할 것으로 판단된다. 아울러 교통량 정산 이외의 속도, 총 주행거리 등 다양한 검증 방법론 개발이 필요하며, 도로부문뿐만 아니라 대중교통의 정산 허용기준 또한 정립되어야 할 것으로 사료된다.

INTEGRITY ANALYSIS OF AN UPPER GUIDE STRUCTURE FLANGE

이기형 한국원자력학회 2015 Nuclear Engineering and Technology Vol.47 No.6

The integrity assessment of reactor vessel internals should be conducted in the designprocess to secure the safety of nuclear power plants. Various loads such as self-weight,seismic load, flow-induced load, and preload are applied to the internals. Therefore, theAmerican Society of Mechanical Engineers (ASME) Code, Section III, defines the stress limitfor reactor vessel internals. The present study focused on structural response analyses ofthe upper guide structure upper flange. The distributions of the stress intensity in theflange body were analyzed under various design load cases during normal operation. Theallowable stress intensities along the expected sections of stress concentration werederived from the results of the finite element analysis for evaluating the structural integrityof the flange design. Furthermore, seismic analyses of the upper flange were performed toidentify dynamic behavior with respect to the seismic and impact input. The mode superpositionand full transient methods were used to perform timeehistory analyses, andthe displacement at the lower end of the flange was obtained. The effect of the dampingratio on the response of the flange was also evaluated, and the acceleration was obtained. The results of elastic and seismic analyses in this study will be used as basic information tojudge whether a flange design meets the acceptance criteria.

자분탐상시험과 침투탐상시험의 기법별 검출능 및 합부판정 요건에 대한 고찰

최헌식,서상철,윤종학,탁경주 한국비파괴검사학회 2023 한국비파괴검사학회지 Vol.43 No.6

비파괴검사는 1970년 국내 산업계에 처음 도입된 이후 현재까지 조선해양산업, 기계산업 ,원자력/화력 발전설비와 항공우주산업 등의 신뢰성과 안전성 확보를 통해 설비의 운영효율을 제고하고, 중대사고를 미연에 방지함으로써 사회적 안전에 크게 기여하고 있다. 현재 국내 산업에 적용하는 규격의 합부판정은 해외규격을 단순히 번역하여 이해하고 적용하는 것에 관심을 두고 있었기 때문에 표준에서 합∙부 판정 기준이 최초 어떻게 제정되어 졌는지, 어떠한 과학적, 기술적 근거와 실험적 기준으로 제정되었는지, 이러한 국제 표준이 국내 산업계에 적합한지에 대한 고찰이 부족한 것이 현실이며, 비파괴검사의 이론적, 기술적 근거를 강화한다면 한층 더 발전할 수 있는 기회가 될 것으로 사료된다. 본 고찰에서는 자분탐상검사(MT)와 침투탐상검사(PT)를 적용한 동일한 크기의 결함에 대해 비파괴검사 방법 및 기법별로 어떠한 검출 결과가 도출되는지에 대하여 평가하여 원형 및 선형 지시에 대해 두 검사 방법이 미미한 차이는 있었지만 검출능력은 모두 우수하였고, 지시의 길이 및 형상에서 유사한 결과(평균0.22mm)를 확인하였다. 또한, 국제규격에 따른 합부판정을 비교해 볼 때 대부분의 규격에서 표면결함에 대해동일하게 규정되어 있으나, ISO 규격에서 차이가 있는 것으로 확인되었다. Nondestructive testing was first introduced to the domestic industry in the late 1970s, and efforts are being made to ensure the safety of the nuclear industry and nuclear power for the customer and the public. Because the acceptability of domestic industry standards is currently concerned simply with the translating, understanding, and application of foreign standards, it is difficult to know how the acceptability criteria in the standard were first established and on what scientific and technical bases and on what experimental criteria. The suitability of the established international standards for the domestic industry has not been considered sufficiently. It is believed that strengthening the theoretical and technical bases of nondestructive testing can provide an opportunity for further development. In this review, we evaluate detection results for each nondestructive testing method and technique for defects of the same size using magnetic particle testing (MT) and penetrant testing (PT) and compare the two inspection methods for circular and linear indications. Although there were slight differences, the detection abilities were all excellent, and similar results (average 0.22 mm) were confirmed in the lengths and shapes of the indications. In addition, when comparing acceptability judgments according to international standards, it was confirmed that surface defects are equally defined in most standards but with differences in ISO standards.

Establishment of Management System for Radioactive Waste Containings Hazardous Substances

Yunjeong Hong,Dongju Lee,Daeseong Nam,Jonghwa Pack,Yungun Jung,Heungju Cho,Sungjin Han,Wonhyuk Jang,Tackjin Kim 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.2

As the acceptance criteria for low-intermediate-level radioactive waste cave disposal facilities of Korea Radioactive Waste Agency (KORAD) were revised, the requirements for characterization of whether radioactive waste contains hazardous substances have been strengthened. In addition, As the recent the Nuclear Safety and Security Commission Notice (Regulations on Delivery of Low- Medium-Level Radioactive Waste) scheduled to be revised, the management targets and standards for hazardous substances are scheduled to be specified and detailed. Accordingly, the Korea Atomic Energy Research Institute (KAERI) needs to prepare management methods and procedures for hazardous substances. In particular, in order to characterize the chemical requirements (explosiveness, ignitability, flammability, corrosiveness, and toxicity) contained in radioactive waste, it must be proven through documents or data that each item does not contain hazardous substances, and quality assurance for the overall process must be provided. In order to identify the characteristics of radioactive waste that will continue to be generated in the future, KAERI needs to introduce a management system for hazardous substances in radioactive waste and establish a quality assurance system. Currently, KAERI is thoroughly managing chelates (EDTA, NTA, etc.), but the detailed management procedures for hazardous substances related to chemical requirements in radioactive waste in the radiation management area specified above are insufficient. The KAERI’s Laboratory Safety Information Network has a total periodic regulatory review system in place for the purchase, movement, and disposal of chemical substances for each facility. However, there is no documents or data to prove that the hazardous substances held in the facility are not included in the radioactive waste, and there are no procedures for managing hazardous substances. Therefore, it is necessary to establish procedures for the management of hazardous substances, and we plan to prepare management procedures for hazardous substances so that chemical substances can be managed according to the procedures at each facility during preliminary inspection before receiving radioactive waste. The procedure provides definitions of terms and types of management targets for each characteristic of the chemical requirements specified above (explosiveness, ignition, flammability, corrosiveness, and toxicity). In addition, procedure also contains treatment methods of radioactive waste generated by using hazardous substances and management methods of in/out, quantity, history of that substances, etc. As the law is revised in the future, management will be carried out according to the relevant procedures. In this study, we aim to present the hazardous substance management procedures being established to determine whether radioactive waste contains hazardous substances in accordance with the revised the notice and strengthened acceptance criteria. Through this, we hope to contribute to improving reliability so that radioactive waste could be disposed of thoroughly and safely.

Introduction of Test Devices for Radwaste Characterization Specimen

Yoon-do Oh,Dae-seok Hong 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.1

In this introduction, test devices for radwaste characterization specimen was developed and utilized. In order to permanently dispose of solidified radwastes, not only radioactive characterization but also physical & chemical characterization shall be performed to assess compliance with the waste acceptance criteria. Waste acceptance criteria can be made up measurement of free standing water, compressive strength test, thermal cycling test, radiation resistance test, leaching test, immersion test. Approximately, the equipment for each test is sorted out five types. equipment for making characterization specimen, equipment for compressive strength test, equipment for thermal cycling test, equipment for radiation resistance test, equipment for Immersion test and leaching test. Equipment for making characterization specimen is operated the dry process. The equipment of two types: one (sampling device) that cores solidified radioactive waste in a drum, and the other (cutting machine) that properly cuts the coring samples. Sampling device is not used in industry, so it is specially manufactured, cutting machine is using ready-made products. In addition, devices for compressive strength test and thermal cycling test are using ready- made products. Facility for Radiation resistance test is located in Jeong-eup. For the efficient test, a table was manufactured in the columnar form like the specimen. Finally, devices for immersion test and leaching test are so transformed that contact all surfaces of the specimen with the liquid.