• Title/Summary/Keyword: 중성자 회절

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Study on the Preferred Orientation Using White Neutron

  • Lee, Yun-Peel
    • Nuclear Engineering and Technology
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    • v.6 no.4
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    • pp.219-230
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    • 1974

  • The previous expression for the diffracted neutron intensity by a highly oriented polycrystalline is modified using the Kunitomi's formula of the crystal reflectivity The method of studying the preferred orientation in metals with white neutron is proposed utilizing the above formula and the fact that the real position of the diffraction of certain grain in the sample can be found by the comparison of the smaller angle part of the maxwellian curve of the calculated intensity of neutrons diffracted and the experimenal curves. The most probable wavelength of thermal neutrons from the reactor is found by the measurement of the neutron spectrum with the correction for the crystal about the multiple reflection and the absorption of neutrons and turned out to be 1.025 $\pm$ 0.001$\AA$. The preferred orientations of some electric steel sheets, mostly with the cube-on-face orientations, are investigated by the present method. The orientations of most grains relative to the rolling directions are found to be within 5 degrees. It is found the most of theories for large crystals may be extended to highly oriented polycrystalline materials without extensive modification.

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Study of the Nondestructive Test Method for the Embrittlement Evaluation of Nuclear Reactor Vessel Material by $M{\ddot{o}}ssbauer$ Spectroscopy ($M{\ddot{o}}ssbauer$ 분광법에 의한 원자로 용기재료의 비파괴적 중성자 조사평가에 대한 연구)

  • Jung, M.M.;Jang, K.S.;Yoo, K.B.;Kim, G.M.;Yoon, I.S;Hong, C.Y.
    • Journal of the Korean Society for Nondestructive Testing
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    • v.20 no.3
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    • pp.183-190
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    • 2000

  • The purpose of this study is to evaluate the magnetic property change of the nuclear reactor vessel steel irradiated by fast neutrons using $M{\ddot{o}}ssbauer$ spectroscopy, and the effects of the defects produced by neutron irradiation on the changes using X-ray diffraction. The specimens, fabricated with the dimension of $23mm{\times}18mm{\times}70{\mu}m$, were irradiated by neutron fluence from $10^{12}n/cm^2\;to\;10^{18}n/cm^2$ at 343K. Throughout the experiments, it is understood that (1) the X-ray diffraction measurement shows that the change of crystal nature is started at the irradiation of $10^{16}n/cm^2$ and a crystal structure has been severely damaged at the irradiation over $10^{17}n/cm^2$, (2) the analysis of the $M{\ddot{o}}ssbauer$ spectra has shown that magnetic transition phenomena occur at the irradiation over $10^{17}n/cm^2$ and (3) both methods can be utilized as nondestructive test methods for the embrittlement evaluation of materials irradiated by fast neutrons.

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A study on neutron diffraction of amorphous Ni-Ta and Cu-Ta alloy powders prepared by mechanical alloying (기계적 합금화법으로 제조한 비정질 Ni-Ta 및 Cu-Ta 합금분말의 중성자회절에 관한 연구)

  • Lee, Chung-Hyo;Lee, Jin
    • Electrical & Electronic Materials
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    • v.8 no.6
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    • pp.715-720
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    • 1995

  • 기계적 합금화법에 의한 비정질화 과정을 Ni-Ta계 및 Cu-Ta계에 대하여 조사하였다. Ni-Ta합금계는 혼합엔탈피가 음이나, Cu-Ta계는 혼합엔탈피가 양인 열역학적으로 대조적인 합금계이다. 볼밀 중 발생하는 원자구조 변화를 중성자회절법을 이용하여 관찰하였다. 두 합금게에 있어서 기계적 합금화에 의한 비정질상이 생성되었다. 비정질 Cu-Ta합금의 local원자구조를 혼합엔탈피가 크게 음인 Ni-Ta계의 결과와 비교하였다. 그 결과, 대조적 특성을 가진 두 합금계임에도 불구하고 원자크기가 작은 Ni 및 Cu가 bcc Ta의 결정격자 속으로 우선적으로 침입함으로써 비정질화가 진행됨을 알 수 있었다.

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