METHOD FOR MONITORING CHANGES IN SHAPE OF NUCLEAR REACTOR PROCESS CHANNEL Russian patent published in 2002 - IPC

FIELD: pressurized-tube uranium- graphite reactors. SUBSTANCE: method for estimating curvature of peripheral process channels throughout entire service life of type RBMK reactor involves following procedures. Lower end of peripheral process channel mounted in reactor is marked with fiducial point. Its position through height is determined during first start of reactor with this process channel at different power levels and data obtained are used as reference data. Spatial position of fiducial point is then traced in the course of reactor operation. Curvature in process channel is recognized by discrepancy between present and reference data. Channel sag is found from formula where Lc is length from upper end of process channel to fiducial point measured during check procedures, m; D is difference between present position of fiducial point and reference value, m. Process channel is decommissioned in case channel sag exceeds 5•10^-2 m. EFFECT: provision for on-line estimation of channel curvature throughout entire service life of reactor. 2 cl