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Hydrogen Embrittlement of Zr-2.5Nb Pressure Tube at Room Temperature by Precipitated Hydride

수소화물에 의한 Zr-2.5Nb 압력관의 상온 수소취화 거동

  • Published : 2003.03.01

Abstract

The aim of this study is to investigate the hydrogen embrittlement of Zr-2.5Nb CANDU pressure tube at room temperature. The transverse tensile and fracture toughness tests were performed at various hydrogen concentrations using transverse tensile specimens and CCT (curved compact tension) specimens. These specimens were directly machined from the pressure tube retaining original curvatures. Based on the results of these tests. the hydrogen embrittlement phenomenon was clearly observed and fracture toughness parameters of Zr-2.5Nb pressure tube materials such as, $K_{J(0.2)}$.$J_{ML}$.dJ/da, were dramatically decreased with the increasement of the hydrogen concentration. From microscopic observation by SEM and TEM, it was also revealed that various shapes dimples, fissures and quasi-cleavage were found at the hydrogen-absorbed materials with hydrides while traditional shape dimples were generally located at the as-received materials Through the comparison of the hydride and fissure lengths with the hydrogen concentration the new evaluation method of hydrogen embrittlement was suggested.

Keywords

Hydrogen Embrittlement;CANDU Pressure Tube;Curved Compact Tension Specimen;Hydride;Fissure

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