[en] Results from the human reliability analysis task of the Three Mile Island unit 1 (TMI-1) probabilistic risk assessment (PRA) have been and continue to be used to focus improvements in plant operations. The original TMI-1 PRA was published in 1987. This initial study computed the core damage frequency (CDF). In more recent years, an update of the TMI-1 PRA has been performed to satisfy US Nuclear Regulatory Commission requirements for an individual plant examination (IPE). The PRA update, in addition to accounting for design and procedural changes since the original study was completed, extended the scope of the analysis to compute the frequency of release categories. This expansion in scope permits the importance of key human actions to be assessed in terms of the frequencies of release categories as well as the total CDF. Key dynamic human actions identified by these studies are reviewed to determine whether changes can be made to plant operations to lower the human error rates and thereby lower the frequency of core damage and off-site release