Operating floor. Note that none of the shield blocks are shown, but they would sit atop the reactor during operation and be removed for maintenance.

Central Control Rod, Rod Number 9, would be inserted here and is the most reactive in the core. This rod had no reported sticking for the 6 months prior to the accident. No control Rod Drive Motors are shown in this picture because the plant is still under construction.

Emergency exit door opens outward. This exit leads to uncovered exterior stairs. When the first casualty was placed on a stretcher, one of the rescuers had a clogged Scott Air-Pak. The two men attempted to leave the building through this door, but the location of the electrical generator prevented them. They returned down the main stairs with the body.

Ladder down to a fuel storage well? There were 3 fuel storage wells near the main entrance. However, there are two mentions of a "low level room" in IDO-19300 where expended fuel and reactor components were likely stored for shielding purposes.

Rod Number 1, an active control rod, cruciform. It would stick during some operations, so it was operationally limited to 18 inches until a burr on the shroud was removed in November 1960.

Rod Number 8, a Tee shaped rod. There was no rod in the core, so a plate was bolted down as shown here. (Referred to as a blind flange.) Instrumentation wires for thermocouples penetrated the plate. During the accident, this cover plate blew off and the threads of the holddown studs were stripped.

Rod Number 2 was inactive, but it had cadmium poison shims in it to compensate for some disintegrated aluminum-boron strips. It had a blind shield plug installed, like in position 8.

Rod Number 6 was inactive, but it had cadmium poison shims in it to compensate for some disintegrated aluminum-boron strips. During the accident, this port was bolted closed as in the picture.

Rod Number 7, an active control rod, cruciform. It was the rod which was most prone to sticking in the months preceding the accident. Its shield plug impaled an operator to the ceiling above, but the control rod blade remained in the core.

Rod Number 3, an active control rod, cruciform.

Rod Number 5, an active control rod, cruciform. During the time of the accident, this rod had its drive mechanism attached.

Rod Number 4, a dummy control rod, Tee-shaped. Since this was inserted through the port without removing the head, the all-aluminum rod was reduced in size to fit.

Boron storage tank

The walls are rough because of the sprayed insulation

Position #10 is the liquid level sensor for the reactor vessel. It is adjacent to Rod Number 5.

Position #11 is an Auxiliary Nozzle.

Instrument wells (4)

The overhead crane was manually operated.