In Arizona, firefighters were buildingcontainment lines around a 3, 700-acre blaze on the Tonto National Forest to try to protect electric transmission lines that provide power to the state's major metropolitan areas.
Both the drywell and the wetwell are surrounded by a secondary containment vessel (or shield building) also built from reinforced concrete about a meter thick.
The reactor vessels remained intact as did the reinforced concrete containment buildings, but each reactor building lost its hat due to the hydrogen explosions.