FIFTH CANADIAN CONFERENCE ON NONDESTRUCTIVE ... - IAEA

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AN ADVANCED HEAT EXCHANGER EDDY CURRENT INSPECTION SYSTEM
M. Ve.Ve.Mno, H. Ghznt, H. Licht
Atomic Energy oß Canada Limi.te.cl
Chalk Rivz/i, Ontario
ABSTRACT
Heat exchangers are important components in many process industries,
especially nuclear power plants. Nondestructive testing techniques and
equipment are required for fast, reliable testing of heat exchanger tubes
during both unanticipated and scheduled inspections. An advanced eddy
current inspection system has been developed at Chalk River Nuclear
Laboratories to meet this need. This system was designed to meet the needs
of the operator, analyst, station manager and regulatory agencies. The
inspection system provides real-time data acquisition, display, recording and
hardcopying to allow on-line analysis by a qualified eddy current analyst.
In real time, a one page printout containing impedance images and strip chart
traces of eddy current signals is produced for each tube. Tube coordinates,
inspection data, print number and data acquisition validity messages are also
included for record keeping purposes. This record enables the signal analyst
to readily identify, analyze and comment on anomalous signals. Three pairs
of eddy current test data (X and Y components) can be fed into the system.
All three data sets plus probe position and tube information are stored on FM
tape. The operator can select one data set for real-time display. A
sophisticated tape playback feature permits a convenient means of further
analyzing data. The real-time hardcopying allows the inspection team to
provide the utility manager with a copy of the data and inspection results
immediately following the inspection.
This inspection system, known as R'Eddy Record, requires two people to
operate, can realistically inspect 400 tubes/8 h shift, and is compatible
with all commercially available single and multifrequency eddy current
instruments using either absolute or differential type probes.
A particularly impressive feature of the format used to present the data is
the inherent ability of comparing previous inspection data with current
inspection data. This provides a convenient means of monitoring a heat
exchanger's tube performance, and permits long range planning for tube
plugging and/or heat exchanger replacement.
This paper describes the complete inspection system, how it is operated and
field experience to date.