At TMI: 35-year-old ‘design flaw’ fixed

From the Press and Journal:

A design flaw that left the Three Mile Island nuclear plant vulnerable to damage from the severest of floods was corrected by plant engineers last week.

The flaw had existed since the plant was built in the 1970s, officials said.

It was found by engineers on Aug. 21 in an air intake tunnel sump deep inside the Londonderry Twp. plant and reported by plant owner Exelon Nuclear to the U.S. Nuclear Regulatory Commission.

What engineers discovered was a 6-inch diameter pipe that could have allowed flood water into the plant, possibly damaging crucial systems used to keep the reactor from overheating.

The absence of a flood barrier on the pipe “could have prevented the fulfillment of the safety function of structures or systems that are needed to remove residual heat,’’ said an NRC event report. “This condition could have resulted in the unavailability of equipment in the Auxiliary Building.”

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