Early AI Diagnostics at Westinghouse
Figure 3: Westinghouse Steam Purity Analyzer System, ca. 1981. The box was about 5 feet high.
When PDS was unveiled in 1982, the Steam
Chemistry Engineering section, then
managed by the author, had a program of
monitoring and was using data loggers in the
monitor packages. A typical steam purity
analyzer system is shown in Figure 3. It was
placed on a sample line drawing steam from
the steam generator. The sample was
condensed and cooled before it reached the
analyzer panel. The analyzer system
included chemical monitors, a strip chart
recorder and a data logger that was capable
of recording a week of data on a cassette
tape. 7
Thus, the chemists had a significant amount
of online data in digital form and the testing
of PDS started with chemistry. Initially, the
sensors were treated as correct and a small
system was created.
The next iteration started to diagnose the
condition and accuracy of the sensors, which
were generally less reliable than the
equipment they monitored because they
were operating near the detection limits.
Chemical sensors also had the possibility of
failing with a reasonable reading. A sodium
sensor, for example, might stop responding
while displaying 1 ppb (µg/kg), which was a
reading within the normal range. The
7
In the 1980s, most power plants did not have steam samples sent to the central sampling system, so a separate Steam Purity
Analyzer System was required. The usual samples to the central panel included makeup water, condensate, polisher effluent (if
a condensate polisher were present), final feedwater (economizer inlet) and boiler drum water (if the unit had a steam drum).
IIC Journal of Innovation
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