In source models, what is an isolation strategy?

• A. Physical separation of equipment or sections to prevent release from propagating.
• B. Depressurization and shutdown without spatial separation.
• C. Increasing enclosure ventilation to dilute the plume.
• D. Physical separation of equipment or sections to prevent release from propagating; includes depressurization and shutdown.

Answer: (D)

An isolation strategy in source models is a plan to stop a release from propagating by breaking the pathways and reducing the forces that drive it. It relies on physically separating equipment or plant sections so that a release cannot move from one area to another. It also commonly includes depressurizing and shutting down affected equipment to remove the pressure and flow that would push the release further. The combined approach confines any release to a smaller area and reduces risk by preventing spread.

Other options describe only part of this idea or focus on dilution rather than containment: simply separating parts without lowering pressure may still allow flow if a pressure source exists; lowering pressure without spatial separation may not stop propagation along connected routes; increasing enclosure ventilation dilutes the contaminant but does not stop the release from propagating to other areas. The integrated strategy that includes both physical separation and depressurization/shutdown is the correct one.