In the early 1990s, the engineering department at the Susquehanna nuclear plant near Berwick, PA issued a procedure prohibiting the application of a certain coating to components and structures inside the Susquehanna reactor containment building. During a subsequent refueling outage, workers dismantled a component inside the reactor containment building, lugged it outside, and applied the subject coating. They then lugged the re-coated component back into the reactor containment building and reinstalled it.
They successfully satisfied the letter of the procedural requirement, but missed its spirit by a country mile.
The requirement was intended to prevent that coating material from being inside the reactor containment building. If an accident should occur, the conditions inside the reactor containment building could cause the coating material to generate large amounts of hydrogen gas. Fortunately, the misinterpretation was caught and corrected in time.
As with most things, written procedures are clearest in hindsight. It is challenging bordering on impossible to consider every possible interpretation when expressing a direction.
In cases like this one, a way to prevent this type of miscommunication would have been to include some reason for the prohibition within the procedure. The reason would have helped users of the procedure to better understand the context of the mandate so as to be able to follow both the letter of the law and the spirit behind it. But when doing so turns a 4-page procedure into a 90-page tome, that length imposes communication obstacles of its own.
Because communications can never be made invulnerable to misinterpretation, the backstop is like that used in this example. The mistake introduced by the miscommunication was caught and corrected before it caused serious consequences.
“Fission Stories” is a weekly feature by Dave Lochbaum. For more information on nuclear power safety, see the nuclear safety section of UCS’s website and our interactive map, the Nuclear Power Information Tracker.