Incident Chronology at TMI from NRC: 1979-2015

Feb. 10, 2014 – The NRC issued a report on its quarterly inspection of Unit 1 at Three Mile Island. The report covers the fourth quarter from October through December 2013.

In the report, the NRC said it identified two findings of very low safety significance that were being treated as non-cited violations. There also was a licensee-identified violation, also determined to be of very low safety significance that was treated as a non-cited violation.

One NRC finding involved plant operator Exelon’s failure to establish “an adequate program that leak tested components penetrating the primary containment pressure boundary.” Specifically, the NRC said, Exelon “failed to perform leak rate testing of the reactor building normal closed loop cooling piping and failed to identify the degraded piping condition that impacted the containment isolation function.”

Download Document