A power supply that employs automatic switching of main power supply from primary to secondary (usually battery and/or diesel generator) upon failure of the primary. A means of providing uninterrupted power to critical instrumentation for a limited period of time even in the event of a plant power...
An event in a fault tree that is not developed because it is of no significance, because more detailed information is unavailable, or because its frequency or probability can be estimated without determining its basic events.
CCPS RBPS Pillar II: Its two Elements provide hazard and risk information required to plan, develop, and implement stable, reduced-risk operations in the facility.
When a flammable vapor is released, its mixture with air will form a flammable vapor cloud. If ignited, the flame speed may accelerate to high velocities and produce significant blast overpressure.
A procedure-based hazard evaluation technique, similar to a HAZOP Study, in which the adequacy of existing safeguards is evaluated by asking what would happen if each step in a procedure was 1) skipped or 2) performed incorrectly.
A scheduled shutdown period when planned inspection, testing, and preventive maintenance, as well as corrective maintenance such as modifications, replacements, or repairs is performed.
Any change being made to an existing process, or any new facility being added to a process or facility, or any other activity that a facility designated as needing a pre-startup safety review. One example of a non-change-related trigger event is performing a PSSR before restart after an emergency...
