Development of a Method for Rapid Assessment of Both Fuel Channels and Graphite Stack Geometry in RBMK Reactor
S. Vinogradov, Nuclear Power Engineering Institute
ABSTRACT
Periodic inspection of fuel channels (FC) and graphite columns (GC) geometrical parameters in a RBMK reactor is an indispensable prerequisite for its safe operation. The most important FC and GC geometrical parameters are: FC internal diameter, FC wall thickness, value of a gas gap between FC and GC as well as curvature of the FC axis (1). Until now, the procedure for the gas gap value assessment was based on diameter measurements before and after withdrawal of the fuel channel. At the same time, examination of other geometrical parameters are carried out with high speed without removing of fuel channels (2). To accelerate the evaluation process of the FC and GC geometry changes, some new approaches to the gas gap value examination are under development today. This paper discusses the method of an indirect estimation of the gas gap value between FC and GC to be carried out without removing the fuel channel. The method is based on an analysis of a temperature field distribution on the fuel channel walls while there is the presence of an artificially created temperature gradient between the graphite stack and coolant within the fuel channel (3). Sensitivity of the method was analyzed on mathematical models and experimental simulators. An opportunity of an industrial application of the method was investigated at 2-d unit of Kursk Nuclear Power Plant during a scheduled maintenance procedure in 1999.
Publication Source: 2nd International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurized Components, May 24-26, 2000, New Orleans, Louisiana USA. Publisher: EPRI - [Homepage]
