原子力發電所의 確率論的 安全基準設定에 관한 硏究

黃元國 慶熙大學校 1992 論文集 Vol.21 No.-

Even though many reseachers have been studying the criteria for the safety of nuclear power plants, which are related to the issue of “How Saffe is Safe Enough”, any clear answer has not been given yet. The activities of US Nuclear Regulartory Commission toward establishing the safety goal was partly to answer the question as well as to provide the public understanding on the safety issues. Establishing Probabilistic Safety Criteria (PSC) for nuclear plant should be to balance with other inherent societal risks. Even though PSC is conceptual and mathematical tools for nuclear power plant regulation, it involves safety philosophy and cultural backgrounds. Recently the public has increasingly interested in nuclear risks in Korea. Accordingly, there has been emphasized to establish PSC. Findings of the present study are as follows ; (1) The quantitative PSCs cannot be determined through simple technical approach. Especially, ascceptable risk should be determined considering our cultural and philosophical bases. (2) A PSC can be established to core damage probability of 10^-4-10^-5/RㆍY, and other PSCs should be established after performing related studies.

安全性 哲學 確立에 관한 硏究(Ⅰ) : 이슈와 分析 Issues and Resolutions

黃元國,李源根 慶熙大學校 1989 論文集 Vol.18 No.-

A series of pesent studies is to develop the safety philosophy of a technology, The issues : statistical problems regarding the assessment of rare events and safety measure of radiation exposure, are selected as the present topics and potential resolutions that represent our subjective views are given provding that further refinements will he studied on the issues.

Fuzzy 集合槪念을 利用한 故障樹木分析의 한 方案

黃元國,市橋秀友 慶熙大學校 1986 論文集 Vol.15 No.-

An axiomatic approach to fuzzy measure is presented via the concept of triangular norm(t-norm for short). Fuzzy measures are actually set functions which are monotonic with respect to set inclusion. Triangular norm and conorm are semi-groups of the unit interval. Based on the proposed fuzzy measures, AND, OR and NOT gates of fault tree are defined, and fuzzy membership function for component reliability is suggested for the future nesearch on the fuzzy fault tree analysis.

Revised-BERD : A Computer Code for Updating Reliability Data Using Bayes´ Theorem Bayes 정리를 이용한 신뢰도 자료개선용 전자계산기 코드

Hwang, Won-Guk,Cho, Dae-Hyung 慶熙大學校 1987 論文集 Vol.16 No.-

로그정규분포를 채택하여 특정 원자력발전소 안전성 계통을 신뢰도 분석을 위한 자료평가의 목적으로 개발된 전산코드 BERD가 개선되고 시험되었다. 모우먼트 일치법과 최대공산법을 이용하여 감마 및 베타 선분포의 모수를 추정하는 옵션이 추가되었다. Revised-BERD를 이용한 시험결과, 로그정규분포가 감마 및 베타분포와 비교하여 보수적임을 보여 주었다. A Computer code, BERD, which accepts only log-normal distribution. has been revised and tested in odrder to update the data for the reliability analysis of safety related systems in a specific nuclear power plant. New options are added to estimate the parameters of gamma and beta prior-distributions facilitating the matching moment and the maximum likelihood methods. The test results using the Revised-BERD show that the log-normal distribution is conservative compared with gamma and beta distributions.

가압경수로 보조급수계통의 퍼지고장수목분석에 관한 연구

이창균,황원국 慶熙大學校 1991 論文集 Vol.20 No.-

Fault Tree Analysis(FTA)has been widely used to analyze the reliability of large and complex engineering systems. FTA is based on probability theory, and would be perfect when all data were defined manifestly. However, when data is infered from expert's judgement of the human error is quantified, this methodology may not apporopriate because of inherent fuzziness of the data used. In this regard, a possible alternative is to utilize Fuzzy Fault Tree Analysis(FFTA)methodology which is based on a possibilistic approach using the expression with natual language for the various fuzziness. In this paper, a possibilistic approach and fuzzy probabilistic approach based on fuzzy set theory are suggested, and the results of the evalution of failure possibity and fuzzy measure for the Auxiliary Feedwater System of Pressurized Water Reactor given in WASH―1400 are presented.

벤치마크 검증을 통한 WIMS/D 라이브러리 생산 방안에 관한 연구

박병철,황원국 慶熙大學校 1994 論文集 Vol.23 No.-

A set of libraries of WIMS/D are generated from the recently released evaluated nuclear data files, ENDF/B-VI, using ENDF processing code system HJOY on PC-486. In order to select proper processing parameters, a series of thermal reactor benchmark problems are tested, several important parameters are selected for the sensitivity analyses. The result of present study shows that the proper processing parameters for the light-water moderated benchmark lattices are the followings; 1) Maxwellian-1/E-Fission spectrum for cross section averaging, 2) simple NR approximation which does not include the potential scattering of the absorbers in resonance range for resonance integral tables, 3) the ^235U fission spectrum with adjusted with 10% ^238U fission spectrum.

增倍媒質에서의 중성자수송의 推計論的 성질에 관한 연구

李基文,黃元國 慶熙大學校 1989 論文集 Vol.18 No.-

In the present study, pairwise generating functions, which are inter-related and mathematically analytical for existing moment-dependent parameters, arc newly defined for replacing Bell and Pal types, which do not have any relations in their definitions to find out moment-dependent parameters. The suggested method in this study has successfully applied to the stochastic neutron transport equation.

A Study on the Dose Assessment Methodology Using the Probabilistic Characteristics of TL Element Response

Oh,Jang-Jin,Han,Seung-Jae,Cho,Dae-Hyung,Hwang,Won-Guk,Na,Seong-Ho,Lee,Won-Keun 대한방사선 방어학회 1998 방사선방어학회지 Vol.23 No.3

개인피폭선량 평가용 열형광선량계인 UD802선량계에 대한 X-선장, 감마선장, 베타선장 및 중성자선장의 순수선장과 X-선장/감마선장, 베타선장/감마선장 및 중성자장/감마선장의 혼합선장에서의 반응특성으 조사하였으며 소자반응이 확률적으로 분포 성질을 이용한 개인피폭선량 평가방법을 개발하였다. 선량계 특성조사를 위한 기준조사는 한국원자력안전기술원의 X-선장, 베타선장 및 감마선장을 이용하였으며 중성자선장은 미국PNL에 의뢰하여 수행하였다. 특성조사 겨러과 광자선장에 대한 소자1과 소자2는 에너지에 대한 의존성이 매우 적어 선량당량의 계산시 매우 유용한 자료로 사용되어질 수 있으며 소자3과 소자4는 저에너지 및 중에너지의 광자선장에 대해 매우 민감한 변화를 보이고 있다. 소자1/소자3 및 소자1/소자4의 반응비는 베타선장과 중성자선장에 대하여 에너지의존성이 큰 반응비를 나타내며, 소자3/소자2의 반응비는 중성자선자에 대해서만 1이하의 값을 나타내고 있다. 저에너지 및 중에너지 광자선장에 대한 에너지 분별은 소자3/소자2 및 소자3/소자4의 반응비로서 가능함을 확인하였다. 본 연구에서 개발한 확률분포 분석법의 적용가능성을 보이기 위하여 Panasonic UD716AGL/ UD802 판독시스템에 적용하여 ANSI N13.11-1993에 따른 성능검증을 수행하였다. 성능검중 결과 모든 범주에 대하여 성능지수,[B]+S가 최대 0.232의 성능이 확인되었다. 특히 일부 소자의 비정상적 반응에 대해서도 최적의 피폭선량평가를 수행하고 있음이 확인되었으며, 실험실에서 재현될 수 없는 실제 방사선작업 환경에서의 선량평가 수행시, 본 논문에서 제시한 선량평가방법에을 적용할 경우 계획된 피폭과 예상하지 못한 방사선장에 대한 피폭을 구분할 수 있어 보다 심도 있는 피폭선량평가 및 방사선관리가 가능할 것으로 판단된다. Characteristics of element responses of Panasonic UD802 personnel dosimeters in the X, β, r, r/X, r/β and r/neutron mixed fields were assessed. A dose-response algorithm has been developed o decide the high probability of a radiation type and energy by using the distribution in all six ratios of the multi-element TLD. To calculate the 4-element response factors and ratios between the elements of the Panasonic TLDs in the X, β, and r radiation fields. Panasonic's UD802 TLDs were irradiated with KINS's reference irradiation facility. In the photon radiation field, this stusdy confirms that element-3 (E-3) and element-4(E4) of the Panasonic TLDs show energy dependent both in low- and intermediate-energy range, while element-1 (E1) and element-2 (E2) show little energy dependency in the entire whole range. The algorithm, which was developed in this study, was applied to the Panasonic personnel dosimetry system with UD716AGL reader and UD802 TLDs. Performance tests of the algorithm developed was conducted according to the standards and criteria recommended in the ANSI N13.11. The sum of biases and standard deviations was les than 0.232. The values of biases and standard deviations are distributed within a triangle of a lateral value of 0.3 in the ordinate and abscissa, With the avove algorithm, Panasonic TLDs satisfactorily perform optimum dose assessment even under an abnormal response of the TLD elements to the energy imparted. This algorithm can be applied to a more rigorous dose assessment by distinguishing an unexpected dose from the planned dose for the most practical purposes, and is useful in conducting an effective personnel dose control program.