• 대한기계학회논문집A
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• 제25권9호
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• pp.1350-1358
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• 2001

During the last decade, a number of experiments and numerical analyses had been performed in conjunction with the development of simplified analytical methods to estimate the fracture behavior of cracked piping in nuclear power plant. However, the necessity of further investigation for the analytical methods was issued because of the discrepancies with the experimental data. The objective of this paper is to find out the optimum methods to evaluate the load-carrying capacities for cracked pipes. To do this, numerous analytical and finite element analyses were carried out for various pipe and crack geometries and materials. These results were synthesized for crack shapes and can be used as basic data for leak before analyses and risk informed inspections.

• 대한기계학회논문집A
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• 제25권10호
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• pp.1567-1574
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• 2001

In order to operate an RPV safely it is necessary to keep the pressure-temperature (P-T) limit during the heatup and cooldown process. While the ASME Code provides the P-T limit curve for safe operation, this limit curve has been prepared under conservative assumptions In this paper the effects of conservative assumptions involved in the P-T limit curve specified in the ASME Code Sec. XI were investigated. Three different parameters the crack depth the cladding thickness and the cooling rate, were reviewed based on 3-D finite element analyses. Also the constraint effect on P-T limit curve generation was investigated based on J- T approach. It was shown that the crack depth and the constraint effect change the safe region in P-T limit curve significantly Therefore it is recommended to prepare a more precise P-T limit curve based on finite element analysis to obtain P-T limit for safe operation of an RPV.