Application of Volume-Integral Models to Steam Generator Tubing

Abstract

The nuclear power industry faces the serious challenge of convincing a skeptical public and regulatory agencies that it can operate safely and efficiently. Nondestructive evaluation (NDE) plays a significant role in this task, and computer modeling is playing a significant role in NDE. The industry now realizes the value of using such modeling to replace expensive experimental tests, as well as to design equipment, and interpret results. Eddy-currents have a traditional place in the inspection of steam generator tubing, and the industry seeks improved tools for such inspections. In this paper, we describe progress in developing a general axisymmetric model that will be part of the volume-integral code, VIC-3Dl. This model will be capable of analyzing tubes with tube supports and rolled-expansion transition zones. Features such as magnetite, sludge, etc., will be included, and materials may be either ferromagnetic or non-magnetic. The model described in this paper will include only differential (or absolute) bobbin coils. Flaws can be of three types: (1) axisymmetric (such as circumferential rings), (2) the usual thin, axially-oriented, crack that is part of VIC-3D's present library, and (3) user-defined flaws, such as inter-granular attack (IGA).

Recent Developments in Eddy-Current Modeling

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In [1] we developed a volume-integral eddy-current modal that is applicable to steam generator tubing. The modal is now implemented in VIC-3D 1 , andin this paper we present some results computed with it.

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