MODE 5, reactor outage, is defined by which shielding condition?

MODE 5, reactor outage, is defined by which shielding condition?

• A. Anytime less than two layers of concrete shielding are fully installed over the top of the core area with fuel in the core.
• B. Two layers of shielding are fully installed over the core area.
• C. No shielding is installed over the core area.
• D. Three layers of shielding are fully installed over the core area.

Answer: (A)

MODE 5 is defined by the shielding configuration around the core during outage. Specifically, if there are less than two layers of concrete shielding fully installed over the top of the core area with fuel in the core, the plant is in MODE 5. This reflects an outage state where shielding is reduced to allow maintenance and refueling activities, leading to higher radiation levels and the appropriate radiological controls. If two layers are installed (or more), or if there is no shielding or three layers, those conditions correspond to different operational states, not MODE 5.

MODE 5 is defined by the shielding configuration around the core during outage. Specifically, if there are less than two layers of concrete shielding fully installed over the top of the core area with fuel in the core, the plant is in MODE 5. This reflects an outage state where shielding is reduced to allow maintenance and refueling activities, leading to higher radiation levels and the appropriate radiological controls. If two layers are installed (or more), or if there is no shielding or three layers, those conditions correspond to different operational states, not MODE 5.