He dreamed Jessie was falling into the fission chamber of a nuclear power plant, falling and falling.

Fission chamber three checks.

Perhaps, with their greater mathematical ability and closer comprehension of what actually went on inside the nuclear fission chamber, they had some vivid glimpse of the mind-shattering horror locked up beyond that shield.

Power is monitored via three different and independent detectors that sit inside the core structure; there is a compensated ion chamber, an uncompensated ion chamber, and a fission chamber in three of the four corners of the grid box.