portions of investigations to other personnel. For example, the initial review
following a plant transient might be conducted by the on-shift shift manager;
the results of this investigation will establish the need for further review.
The process of investigation begins with collecting data. Facility guidelines
should identify the types of information that will be needed in an investigation,
and the methods that should be used to collect and preserve the information.
Operations logs, round sheets, and statements from persons present during the
event would typically be required for any investigation. Use of prepared forms
for personal statements can aid in obtaining and documenting relevant
information for the investigation. A sample personal statement form is shown
in Appendix A.
Some events may warrant collection of physical evidence such as: recorder
charts, readouts from monitoring equipment, photographs and/or drawings of
the area, procedures, technical documents, broken or failed components, and
laboratory analyses. In some situations, it may be necessary to quarantine
certain equipment or systems until the investigation is finished. As soon as
possible after an event, personnel should be assigned responsibility to collect
and/or preserve appropriate information and evidence.
A structured review of the abnormal event should be initiated when all data has
been collected. The format of the investigation depends on the significance of
the event. The steps detailed below should be included in each investigation.
The abnormal event should be reconstructed using the collected
information. When applicable, this is best accomplished using the
sequence of events recorder printout as a basis. A chronological list of
events is developed. It is desirable to include the personnel involved in the
event in the reconstruction process.
Event Analysis and Evaluation
Once the facts have been established, the event may be analyzed to
determine the responses of equipment and personnel. During the analysis,
actual and expected responses of facility systems, adequacy of procedures,