• 제목/요약/키워드: 지르칼로이-4

검색결과 52건 처리시간 0.118초

냉각속도가 지르칼로이-4 피복관의 취성에 미치는 영향 (Effect of Cooling Rate on the Behavior of the Embrittlement in Zircaloy-4 Cladding)

  • 김준환;이명호;최병권;정용환
    • 열처리공학회지
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    • 제18권2호
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    • pp.112-118
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    • 2005
  • Study was focused on the effect of the cooling rate on the embrittlement behavior of Zircaloy-4 cladding simulated Loss Of Coolant Accident (LOCA) environment. Claddings were oxidized at given temperature and given time followed by various water quenching in the range of $0.6^{\circ}C$ and $100^{\circ}C$ per second. Cladding failed after water quenching above the threshold oxidation. Threshold oxidation was decreased as the cooling rate increased, which is due to the matensite structure formed during fast cooling rate.

지르칼로이-4 튜브 프레팅 마멸 특성의 환경 의존성과 마멸기구 (Comparison of Fretting Wear Characteristics of Zircaloy-4 Tube in Light Water and in Air)

  • 조광희;김석삼
    • Tribology and Lubricants
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    • 제15권1호
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    • pp.83-89
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    • 1999
  • The fretting wear behaviour of Zircaloy-4 tube used as the fuel rod cladding in PWR nuclear power plants has been investigated at the different test environment, in light water and in air as a function of slip amplitude, normal load, test duration and frequency. Zircaloy-4 tubes were used for both of oscillating and stationary specimens. A fretting wear tester was designed to be suitable for this fretting test. The wear volume and specific wear rate of Zircaloy-4 tube in water was greater than those in air under various slip amplitude. Delaminates and surface cracks were observed at low slip amplitude and high load of fretting test in water, but the traces of adhesion and plowing were observed at and above 200 Um. The water accelerates the wear of Zircaloy-4 tube at lower slip amplitude in fretting.

경수로 연료용 지르칼로이-4 지지격자의 레이저용접부 조사 (Investigation of the Laser Welded Specimens of Zircaloy-4 Spacer Grids for PWR Fuel Assembly)

  • 김수성;송기남;윤경호;이강희
    • 대한용접접합학회:학술대회논문집
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    • 대한용접접합학회 2006년도 춘계 학술대회 개요집
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    • pp.39-41
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    • 2006
  • The weld quality of spacer grids in Pressurized Water Reactors(PWR) fuel is extremely important for the fuel assembly performance in the nuclear renter. The spacer grid welds are currently evaluated mainly by the metallographic examination although it reveals only cross-points which are welded by the laser beam. This experiment is also to compare the weldability of Zircaloy-4 spacer grids using by the GTA and laser beam. The effect of node geometries of spacer grids for GTAW and LBW has been studied and optimum conditions of spacer grid welding have been found. Microstructures and micro-hardness of GTA and laser beam welded zones have been also compared.

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Zircaloy-4 핵연료봉 레이저 용접부의 고온부식 특성 연구 (Corrosion Properties of Zircaloy-4 Cladding Tube having a Laser Welding Part in Elevated Temperature)

  • 김동균;박진석;김상태;양명승;이정원;김수성;정용환
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 춘계학술대회논문집A
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    • pp.256-261
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    • 2001
  • Corrosion and tensile properties of zircaloy-4 cladding tube having a laser welding part in elevated temperature are studied to present the criterion of quality evaluation in nuclear reactor and to found the scientific basis of SCC, with laser welding method using by coupling up cladding tube to end cap. In the result of tensile test($400^{\circ}C$), the fracture is not happened in the welding part but base metal and the result of corrosion test($400^{\circ}C$ 1500psi steam), corrosion rate of the molten zone and PMZ is a little higher than the other zone.

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고압 고온 수증기에서 지르칼로이-4 산화반응 정량화 및 사고해석에의 응용 (Zricaloy-4 Oxidation Kinetics in High-Pressure High-Temperature Steam and Application to Accident Analysis)

  • 박광헌
    • 한국표면공학회지
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    • 제35권6호
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    • pp.363-370
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    • 2002
  • Empirical equations for the oxide thickness and the weight gain of Zircaloy-4 cladding during the oxidation in high temperature, high pressure steam have been developed. Firstly, the empirical equations for oxide thickness in 1 atm steam in 700~100$0^{\circ}C$ were made, then, the enhancement factor for the steam pressure effects on Zircaloy-4 cladding oxidation in high temperature steam was added. Based on the analysis of the weight fraction of dissolved oxygen in metal layer, empirical equations for the weight gain of Zircaloy-4 in high pressure, high temperature steam were developed. We compare the developed empirical equations with the Baker-Just correlation. The Baker-Just correlation can give a non-conservative estimation of oxidation of Zircaloy-4, depending on the steam pressure. These developed empirical equations can be used for the correct estimation of oxidation of Zircaloy-4 during accident analysis.

수소화시킨 지르칼로이-4의 고온인장성질에 관한 연구 (A Study on the High Temperature Tensile Properties of Hyderiedrided Zircaloy-4)

  • 조열래;정해용;김인배
    • 한국표면공학회지
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    • 제23권1호
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    • pp.44-51
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    • 1990
  • Effects of temperature on the tensile properties of annealed and hydirded Zircaloy-4 plate in which hydrides are precitated paralled to the rolling direction were investigated. The main results obtained are as follows : 1) In annealed Zircaloy-4, yield point phenomenon was found in the temperature range of $200-550^{\circ}C$, while in hydrided alloy the phenomenon was found in the range of $200-400^{\circ}C$. 2) The dynamic strain aging behavior was occurd in the temperature interval of 400-$550^{\circ}C$in both annealed and hydrided Zircaloy-4. 3) The nearly values of yield strength, tensile stength and elongation are obtained in both annealed and hydried Zircaloy-4. From this result, we are led to conclude that the hydrides which are preiptated parallel to the circumferenial direction of nucler fuel are not so harmful for tensile properties of the clad.

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경수중에서 지르칼로이-4 튜브의 프레팅 마멸특성 (Fretting Wear Characteristics of Zircaloy-4 Tube in Light Water)

  • 조광희;노규철;김석삼;조성재
    • Tribology and Lubricants
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    • 제14권4호
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    • pp.88-94
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    • 1998
  • The fretting wear characteristics of Zircaloy-4 tube in light water were investigated experimentally. A fretting wear tester was designed to be suitable for this fretting test. This study was focused on the effects due to the combination of normal load, slip amplitude and number of cycles as the main factors of fretting. The results of this study showed that the wear volume increased abruptly at slip amplitude above 100 ${\mu}{\textrm}{m}$, which is defined as critical slip amplitude of Zircaloy-4 tube in light water, and that under 160 ${\mu}{\textrm}{m}$ the wear volume decreased as load increased at the same slip amplitude.

경수중에서 지르칼로이-4 튜브의 프레팅 마멸특성 (Fretting Wear Characteristics of Zircaloy-4 Tube in Light Water)

  • 조광희;노규철;김석삼;조성재
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 1998년도 제27회 춘계학술대회
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    • pp.55-63
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    • 1998
  • The fretting wear characteristics of Zircaloy-4 tube in light water were investigated experimentally. A fretting wear tester was designed to be suitable for this fretting test. This study was focused on the effects due to the combination of normal load, slip amplitude and number of cycles as the main factors of fretting. The results of this study showed that the wear volume increased abruptly at slip amplitude above 100$\mu$m, which is defined as critical slip amplitude of Zircaloy-4 tube in light water, and that under 160$\mu$m the wear volume decreased as load increased at the same slip amplitude.

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가압경수로용 지르칼로이-4 피복관의 2축 응력 인장시 동적 변형 시효 (Dynamic Strain Aging of Zircaloy-4 PWR Fuel Cladding in Biaxial Stress State)

  • Park, Ki-Seong;Lee, Byong-Whi
    • Nuclear Engineering and Technology
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    • 제21권2호
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    • pp.89-98
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    • 1989
  • 지르칼로이 -4 피복관에 대해서 3가지 변형 속도로(1.2$\times$10E-7/s, 2.0$\times$10E-6/s, 3.2$\times$10E -5/s), 553-873K의 온도 구간에서 구리 맨드렐 팽창 시험법을 공기와 진공(5$\times$10E-5 torr) 분위기에서 수행했고, 변형 속도의 변화는 시편의 가열 속도를 조절함으로써 얻을 수 있었다. 각각의 변형 속도에서 항복 응력 피크와 변형 속도 감도 최저값 그리고 활성화 부피 극대값이 나타나는 이유는 동적변형시효 현상 때문이라고 설명된다. 항복 응력 피크가 나타나는 온도와 변형속도로부터 얻어진 동적변형시효의 활성화 에너지는 196(KJ/mol)이었고 이 값은 $\alpha$-지르코니움과 지르칼로이-2에서 활성화 에너지(207-220 KJ/mol)값과 잘 일치한다. 그러므로 573-673K의 온도 구간에서 나타나는 동적변형시효 현상은 산소원자 때문이라고 생각된다. 산화에 의한 항복 응력의 증가는 공기중 실험과 진공 실험으로 얻어진 항복 응력값을 비교함으로서 얻었고, 그것은 항복 응력의 증가 분율로 표시했다. 결과는 변형속도가 느릴 수록 증가 분율은 더욱 더 커짐을 알 수 있었다. 그리고 산소 침투량과 항복 응력 증가 사이의 관계가 직선적이라는 가정하에 공기와 수중에서의 산화 속도를 비교하여 수중에서의 항복 응력 값을 계산해 보았다.

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($\alpha$+$\beta$) 열처리된 지르칼로이-4에서 집합조직의 변화와 그 조직이 항복 강도에 미치는 영향 (Texture Transformations and Its Role on the Yield Strength of ($\alpha$+$\beta$) Heat Treated Zircaloy-4)

  • Yoo, Jong-Sung;Kim, In-Sup
    • Nuclear Engineering and Technology
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    • 제24권1호
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    • pp.75-85
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    • 1992
  • ($\alpha$+$\beta$) 영역에서 급냉된 지르칼로이-4 판재 시편에서 집합조직의 변화와 그 조직이 0.2% 항복강도에 미치는 영향에 대하여 조사하였다. ($\alpha$+$\beta$) 입자의 크기가 $\alpha$영역에서 소둔된 시편의 입자 크기보다 약간 클 경우 관찰되는 집합조직은 $\alpha$-소둔된 시편의 것 ((0001) 기저폴은 수직 방향에서 방향으로 30$^{\circ}$기울어져 분포)과 비슷하였다. ($\alpha$+$\beta$) 입자 크기가 $\alpha$ -소둔된 시편의 입자 크기보다 2배 정도로 커지면서 기저폴의 최대치는 수직 방향에서 방향 및 압연 방향으로 약 15$^{\circ}$기울어져 분포하여 집합조직은 등방성을 가졌다. 열처리 시간이 길어질수록 Kearns의 집합조직 변수 f는 압연 방향에서 증가하였고 횡 방향에서는 약간 커졌으며 수직방향에서는 계속 감소하였다. 압연 방향의 f가 조금 증가함에 따라 0.2% 항복강도는 크게 증가하였다. 변형 기구에 따른 Schmid인자와 분해전단응력을 구하여 집합조직이 항복강도에 미치는 영향을 조사하였다. 급격한 항복강도의 증가는 주로 미세조직의 변화에 기인하였으며 집합조직이 미치는 영향은 상대적으로 작았다.

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