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Science and Technology of Nuclear Installations
Volume 2017, Article ID 5403701, 13 pages
Research Article

Research on the Computed Tomography Pebble Flow Detecting System for HTR-PM

1Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
2Key Laboratory of Nuclear Detection and Measurement Technology, Beijing 100084, China

Correspondence should be addressed to Zhifang Wu; nc.ude.auhgnist@uw.gnafihz

Received 26 December 2016; Revised 21 March 2017; Accepted 4 April 2017; Published 24 April 2017

Academic Editor: Robert Morris

Copyright © 2017 Xin Wan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Pebble dynamics is important for the safe operation of pebble-bed high temperature gas-cooled reactors and is a complicated problem of great concern. To investigate it more authentically, a computed tomography pebble flow detecting (CT-PFD) system has been constructed, in which a three-dimensional model is simulated according to the ratio of 1 : 5 with the core of HTR-PM. A multislice helical CT is utilized to acquire the reconstructed cross-sectional images of simulated pebbles, among which special tracer pebbles are designed to indicate pebble flow. Tracer pebbles can be recognized from many other background pebbles because of their heavy kernels that can be resolved in CT images. The detecting principle and design parameters of the system were demonstrated by a verification experiment on an existing CT system in this paper. Algorithms to automatically locate the three-dimensional coordinates of tracer pebbles and to rebuild the trajectory of each tracer pebble were presented and verified. The proposed pebble-detecting and tracking technique described in this paper will be implemented in the near future.