방사선 측정 및 해석 연구 : 원자로 냉각수중의 방사능해석에 의한 결함핵연료봉의 평가 Assessment of Defected Fuel by Analysis of Reactor Coolant Activities

양재춘,오희필,전재식,이호연,오헌진,정문규,박해용 충남대학교 기초과학연구소 1987 연구논문집 Vol.7 No.-

중성자와 우라늄의 핵반응에 의해 생성된 핵분열생성물의 물리적 특성을 이용하여 원자로 내의 핵연료 상태를 해석하는 모델을 개선하였다. 이 모델에서는 고체 핵연료 내에서 특정핵종의 핵분열생성물의 생성과 이것이 원자로 냉각재까지 방출되는 과정을 계산하고 추적하여 방사능농도와 결함 핵연료봉의 수를 관계짓는 방정식의 계수들을 결정한다. 핵분열생성물의 거동은 이탈(knock out)과 이동(migration) 두 부분으로 나누어 해석하였으며 트램프 우라늄의 영향을 분리할 수 있도록 하였다. 실측자료로는 가압 경수형 원자로인 고리 원자력발전소 1호기의 1차 냉각재를 분석해서 얻은 I-131과 I-133의 방사능 강도를 이용하였다. 이 실험자료와 위 방정식에서 구한 방사능 강도로부터 구한 결함 핵연료의 수는 제3주기에서 9.34±1.13개 제6주기에서 0.294±0.092개로 나타났다. An improved mothod of assessing fuel status by analyzsis of the fission product in the reactor coolant system is proposed. The release mechanism of specific fission products is established for determination of the coefficients in the equations which relate the radioactivities with the amount of detected fuel. Knock-out and migration models are employed in the formulation of the release mechanism. The influence of the tramp uranium is quantified. Sample calculations were made for KNU 1 reactor system using the I-131 and I-133 concentrations in the primary coolant. The estimated number of defected fuel pins in the third and sixth cycles appeared to be 9.34±1.13 and 0.294±0.092, respectively.

핵연료에서 핵분열 생성물의 방출 기구에 관한 연구

양재춘,이호연,정문규 충남대학교 기초과학연구소 1986 연구논문집 Vol.6 No.-

중성자와 우라늄의 핵 반응에 의해 생성된 핵분열 생성물의 물리적 특성을 이용하여 원자로 내의 핵연료 상태를 해석하는 새로운 모델을 도입하였다. 고체 핵연료 내에서 핵분열 생성물의 생성과 이것의 원자로 냉각재까지 방출되는 과정을 계산하는 방정식을 세웠다. 이 방정식으로 핵분열 생성물의 source term을 계산하고, 이것이 고체 핵연료 내에서 방출되어 gap과 핵연료 피복재를 통하여 원자로 냉각재까지 방출하는 양을 계산하였으며, 원자로 1차 냉각재에서의 tramp uranium양을 계산하였다. 이 방정식을 computer로 계산하기 위하여 전산화 하였다. 실험 자료로는 가압 수형 원자로 (Pressurized Water Reactor)인 고리 원자력 발전소 1호기의 제 3주기 동안에 핵연료의 상태를 감시하기 위해 1차 냉각재를 분석해서 얻은 핵분열 생성물의 방사능 강도를 이용하였다. 이 실험 자료와 위 방정식에서 계산한 방사능 강도를 비교하여 결함 핵연료 수와 tramp uranium 양을 구하였다. 이렇게 구한 결과와 고리 1호기의 제 3주기 말에 핵연료 재장진을 위해 수행한 sipping test 결과를 비교해 보았다. 그 결과 본 연구에서 도입한 모델이 잘 맞는 것을 알 수 있었다. We propose the new model which analyzes the nuclear fuel state of the reactor from the physical characteristics of nuclear fission products which are produced by reactions between neutron and uranium 235. The main feature of this model is to calculate the generation of fission products inside the solid nuclear fuel and the release mechanism of fission products into the reactor coolant. Using the computer we solved the equation of the model and put the experimental activity data of the fission products to determine the number of failed fuel rods and amount of tramp uranium. These data had been taken from the primary coolant of the Kori Nuclear Generating Station, Unit 1. This result of our calculation is in a fairly good agreement with the result of the sipping test during the refueling period for cycle 3 of the Kori Nuclear Generating Station, Unit 1. As a result of this research we conclude that our model for the release mechanism of unclear fission products in reactor fuel is well describing the actual processes.

^40Ca(d,p)^41Ca 직접 핵반응에서의 결합채널방정식에 의한 편극율 계산

양재춘,김성현 충남대학교 기초과학연구소 1995 忠南科學硏究誌 Vol.22 No.2

The polarization ratio of ^40Ca(d,p)^41Ca direct reaction was calculated by coupled channel method with Woods-Saxon optical potential. And the polarization ratio for incident particle energy of 10.8 and 20.8 MeV were calculated in the ground state f and first excited state p of ^41Ca nucleus respectively. The result of coupled channel method was compared with experimental data and a result of distorted wave Born approximation method. It was found that the result of calculation by coupled channel equation agreed with the experimental data and that it was shown CC calculation to be better than DWBA calculation.

중성자의 스핀 구조에 관한 연구

양재춘 충남대학교 기초과학연구소 2002 忠南科學硏究誌 Vol.29 No.1

We have studied on the spin structure of the neutron using ^(3)He target. We have measured inclusive polarized cross sections by scattering high energy polarized electron off the Thomas Jefferson National Accelerator Facility polarized ^(3)He target with both longitudinal and transverse target orientations. The high density ^(3)He target, based on optical pumping and spin exchange, was used as an effective neutron target. A strained GaAs photocathode was utilized in the polarized electron gun, which provided an electron beam with a polarization of about 70%. From the measured cross sections, we extract the ^(3)He spin structure functions g_(1) and g_(2). We extract the neutron spin structure functions from measured ^(3)He ones. Finally. we determine the extended Gerasimov-Drell-Hearn (GDH) sum rule for ^(3)He and the neutron.

CANDU型 原子力發電爐의 反應度 事故解析에 關한 硏究

梁在春 충남대학교 자연과학연구소 1984 忠南科學硏究誌 Vol.11 No.2

The reactivity accident analysis of CANDU-type nuclear reactor has been performed for the case of postulated loss of coolant accident. The analysis has been carried out by using the computer code KIND which has solved the nuclear reactor kinetics equations by means of alternating direction explicit method. The analysis has been performed space-time neutronic behavior of the reactor. The relative average neutron power has been increased during response time with 2.753 times of steady state and decreased during subSequent insertion of shutdown system with 0.865 times of steady state. It has been confirmed that the CANDU-PHW reactor has shutdown capability of shutoff rods system in case of half core loss of coolant accident.

原子爐心에서 中性子 스펙트럼의 測定 및 解析에 關한 硏究

양재춘 충남대학교 자연과학연구소 1983 忠南科學硏究誌 Vol.10 No.2

The experimental technique and analytical method of the neutron spectra are established in the nuclear reactor core. The activities are measured by irradiation of the various threshold detectors in the reactor core and the neutron energy spectra are obtained by using the SAND-Ⅱ code which is based on the spectrum unfolding method. It is found that the initial neutron spectra must be selected by semi-empirical method because the resulting neutron spectra which are calculated by spectrum unfolding method depend on the initial neutron spectra. The results are compared with the neutron spectra values of General Atomics which is the designer of TRIGA Mark-Ⅲ reactor. It is shown that the two values are closely related.

市販 澱粉水解酵素의 活性度 比較

金春子,裵仁淑,梁濟在,李明子,李順子 梨花女子大學校 藥學硏究所 1961 梨花藥學硏究 Vol.- No.2

Ⅲ-Ⅴ족 반도체의 연구 : GaAs의 합성, 단결성 및 특성 Crystal Growth and Characterization of GaAs

이형재,김영기,신영진,박해용,정양준,최춘태,김병호,김진성 全北大學校 基礎科學硏究所 1982 基礎科學 Vol.5 No.1

Temperature of 618 and 1250℃ at As and Ga sities respectively in the horizontal Bridgman furnace and growht speed of 0.7cm/h were found to be optimal for the production of single crystalline GaAs. Self-seeded and unintentionally doped GaAs crystals showd n-type characteristics with Hall mobillity of ∼0.75㎡/V-sec and carrier density of ∼10^19 m^-3 when the mesurements were made right after the growth. About three month later it was found that the same samples were converted to p-type GaAs. The analysis on the p-type sample showed that impurity scattering is dominant at around room temperature and thus the measured Hall mobility was 0.0065㎡/V-sec at 300K. 7.4±0.6 eV was obtained for acoustic deformation potential in the heavy hole band by fitting the theoretical conductivity and Hall coefficient to the corresponding experimental data. The value is very much higher than the theoretically estimated value, 3.6eV. The carrier density variation with temperature obtained from the present analysis gave 0.38 and 0.17 eV respectively for the activation energies of donor and acceptor.

기업 WORKOUT 선정이 주주의 부에 미치는 영향 실증분석

김현재,양춘희 남서울대학교 1999 남서울대학교 논문집 Vol.5 No.-

As more and more companies default on their debt and file for bankruptcy, financial economists have become increasingly interested in understanding how companies deal with financial distress. In this article, we do research how a company workout influences shareholders' wealth. For the event study, we used 34 workout sample of the year of 1998. When a firm workout is determined, investors do think that the state of the company is very bad and that the company is going to be improved. Likewise, the determination of a firm workout has both negative and positive effect. According to the result of the event study, the determination announcement of a firm workout shows abnormal return (t=0) -4.2% and CAR (t=-7, +3) -11%. However, on the contrary to the case of the formal bankruptcy method, it also shows CAR (t=+4, +20) +14.29%. This result is the evidence that the positive effect of a firm workout determination exceeds the negative effect, and it also shows that a firm workout was determined effectively.

^40Ca(d,p)^41Ca 핵반응에서 결합채널방정식에 의한 미분단면적계산

민준기,양재춘 충남대학교 기초과학연구소 1994 忠南科學硏究誌 Vol.21 No.1

Differential cross section and proton polarization have been calculated with coupled channel method in the direct reaction of low energy deuterons and ^40Ca nucleus. The polarizations of proton emitted in the reaction ^40Ca(d,p)^41Ca corresponding to the ground, 6.14 MeV and 4.19 MeV states of ^41Ca at a deuteron energy of 10.8 MeV show good agreement with experimental data. The polarizations of proton show larger in 4.19 MeV state of ^41Ca than in 6.14 MeV state of ^41Ca. Thus the polarizations of proton show spin-orbit dependence of optical potential. Differential cross sections by coupled channel method at deuteron energies of 12 MeV and 13.7 MeV show good agreements with experimental data. And the results of coupled channel calculation show better agreements with experimental data than the results of DWBA calculation at angles forward of 40°where differential cross sections are predominent. Differential cross section corresponding to the first excited state is always larger than that corresponding to the ground state. This means that when a neutron in a deuteron transfer to a nucleus, the target nucleus is in an excited state rather than in a ground state.