報告書番号

E283004

タイトル（和文）

LEAK-BEFORE-BREAK IN STAINLESS STEEL PIPE WITH A CIRCUMFERENTIAL PART-THROUGH CRACK

タイトル（英文）

LEAK-BEFORE-BREAK IN STAINLESS STEEL PIPE WITH A CIRCUMFERENTIAL PART-THROUGH CRACK

概要 （図表や脚注は「報告書全文」に掲載しております）

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概要 （英文）

FREQUENT DISCOVERIES OF STRESS CORROSION CRACKINGS(SCC)IN PRIMARY PIPING SYSTEM OF LIGHT WATER REACTORS URGED STUDIES ON THE SO-CALLED LEAK-BEFORE-BREAK(LBB),WHOSE ESTABLISHMENT IS ANTICIPATED TO CONTRIBUTE TO CONFIRMATION OF PLANT INTEGRITY AS WELL AS PLANT SIMPLIFICATION BY REMOVAL OF THE PIPE RESTRAINTS,WHICH ARE NOW INSTALLED AS A COUNTERMEASURE FOR A POSSIBLE FULL BREAK OF PIPES. WE HAVE BEEN ENGAGING IN A SERIES OF THEORETICAL ANALYSES FOR PLATES AND PIPES OF TYPE 304 STAINLESS STEEL,WHICH WERE TESTED IN THE GOVERNMENT-FUNDED PROJECT IN ORDER TO EXAMINE THE STRUCTURAL INTEGRITY OF NUCLEAR PIPING SYSTEMS. FROM THESE ANALYSES,THE CONSTANT CRACK TIP OPENING ANGLE(CTOA)CONDITION FOR THE DESCRIPTION OF STABLE CRACK GROWTH AND THE INSTABILITY CONDITION REPRESENTED BY THE NET-SECTION STRESS FOR ARBITRARY COMPLIANCECONDITION ARE LED. IN THE PRESENT REPORT,THIS INSTABILITY CONDITION ISAPPLIED TO A PART-THROUGH CRAK GROWTH MODEL,IN WHICH THE ESTABLISHMENTOF THE LBB UNDER THE DESIGN STRESS CONDITION OF ASME CODE SECTION III IS SHOWN AS WELL AS THE AGREEMENT WITH THE EXPERIMENTAL RESULTS.

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