Redesign and Implementation :
subsystems of "Micro-meteorological Monitoring Station" of
Nuclear Power Plant
destroyed by lightning strike


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  • The micro-meteorological monitoring station gathers atmospheric data all year round and records them.

  • These data are later incorporated into the Preliminary Safety Analysis Report (PSAR) and later on, into the Final Safety Analysis Report (FSAR).

  • The regulations require that at least 90% of the data for the whole year must be incorporated into the PSAR.

  • Reliability is, therefore, a primordial requirement for the station.

  • Unfortunately, this station suffered a direct lightning hit in 1976, crippling it.

  • One option was to get a technician from the USA, pay his plane fare, hotel bills, out-of-pocket expenses, and a hefty $400/man-day. The estimate was for him to be at site for 15 days (already consuming 41% of the time allowed by the PSAR).

  • Another option was to try to commission it by myself, with the help of some technicians. My boss realized that the only thing that can happen is for the system to be fixed, not destroyed, since it was not working anyway.

  • On this realization, I was ordered to immediately go to the site and do the best I can to get it to work.

The Work.        

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  • Upon detailed review of the schematics as the 3-hour trip progressed, it was clear that much of the critical devices that could be wrecked were signal conditioners and analog amplifiers.

  • This is so, because of their proximity to the lines coming in from the sensors of the station.

  • This was the first thing that was confirmed.

  • The digital data system were all intact, but almost all the analogs were burned.

  • Operational amplifiers 741 and 301 were substituted for all the analogs.

  • Since the pin designations were not the same as the installed chips, wire leads were soldered to the boards. Many of the 1% and 5% resistors were also replaced with 10%'s in series with potentiometers to provide the calibrated signals.

  • Work started at 4:30 AM, and we were taking our lunch at around 5:00 PM.


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  • With the met station back, an inventory of the affected boards was made the following day.

  • Telexes were then sent to order replacement boards to be shipped by air.

  • Substantial savings was realized.

  • Most of all, the staff developed "ownership" in the work, "confidence" in what can be done, and broke the "myth" that only foreign technicians are capable to take on new technology.