• Transactions of the Korean hydrogen and new energy society
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• v.15 no.4
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• pp.266-273
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• 2004

The objective of this study is an understanding of stress corrosion cracking of metals that is recognized to mostly limit the lifetime of the structural materials by comparing the features of delayed hydride cracking of zirconium alloys with those of stress corrosion cracking (SCC) of Ni-based alloys and hydrogen cracking of stainless steels. To this end, we investigated a dependence of delayed hydride cracking (DHC) velocity on the applied stress intensity factor and yield strength, and correlated a temperature dependence of the striation spacing and the DHC velocity. We reviewed a similarity of the features between the DHC of zirconium alloys, the SCC of Ni-based alloys and turbine rotor steels, and the hydrogen cracking of stainless steels and discussed the SCC phenomenon in metals with our DHC mode.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.54-59
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• 2004

In this paper probabilistic fracture mechanics(PFM) approach is employed to evaluate the integrity of CANDU Zr-2.5Nb pressure tubes. Modified failure assessment diagram(Jr-FAD), plastic collapse, and critical crack length(CCL) approach are used for evaluating failure probability of the tubes. Jr-FAD was extended from the Kr-FAD because fracture of pressure tubes occurs in brittle manner due to hydrogen embrittlement of material by deuterium fluence. For developing the probabilistic integrity evaluation module, AECL procedures and fracture toughness parameters of EPRI were used.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.851-856
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• 1998

국내에서 상업운전중인 월성 원자로는 캐나다에서 개발한 CANDU형 원자로로 핵연료를 지지하는 핵연료 압력관이 사용되며, 핵연료 압력관은 원자로의 1차기기로 건전성확보가 매우 중요하다. 가동중 검사시 압력관에서 결함이 검출되면, 지속적인 사용을 위해서 결함의 건전성을 확보하여야하나, 그 평가절차가 매우 복잡하다. 본 연구에서는 핵연료 압력관 평가를 보다 신속하고 효율적으로 수행하기 위한 건전성 평가시스템을 개발하였다. 개발된 평가시스템은 예리한 결함 및 둔한 함에 대한 평가를 수행할 수 있으며, 피로균열평가, 지체수소균열평가, 불안정파괴평가, 파단전누설평가, 소성붕괴평가모듈을 수록하고 있다. 또한 개발된 시스템을 검증하기 위하여 캐나다 ECL에서 제시한 평가결과와 비교함으로서 본 시스템의 효용성을 검증하였다.