and factors affecting human performance are compared. An evaluation to
identify any detrimental effects on plant equipment should be included.
The event should be compared with previous investigations of similar
events or transients. If the event was a reactor trip, the acceptability of
restart is determined.
Root Cause Determination
The root causes of the event should be determined whenever possible.
Root causes are those fundamental causes that would have prevented the
event from occurring and, if corrected, prevent recurrence. Typically
correctable without additional research or analysis, root causes explain
why direct causes existed.
Corrective Action Determination
Each event investigation results in corrective action being established, and
specific personnel are assigned responsibilities for such action. Corrective
action can be procedure changes, training, design modifications, and
administrative controls changes; and may include better supervisory
involvement and oversight of work activities and increased worker
accountability. Interim compensatory actions may be used while longer-
term corrective actions are being developed. Cognizant managers should
agree to each corrective action before it is performed, and the facility
manager approves it.
An essential part of the investigation is informing others, so recurrence of the
event can be prevented. A report of the investigation, including discussion and
explanation of the results of the analysis and identification of the corrective
actions, should be prepared in accordance with facility guidelines. The
investigation report should be reviewed by appropriate managers, supervisors,
and the safety review committee to ensure that lessons learned from the event
are identified and incorporated into applicable facility programs as discussed in
section 4.2.5. The final report should be reviewed and approved by the facility
Those occurrences requiring formal notification, in accordance with DOE
Order 232.1A, also require a formal occurrence report. Instructions for