The HAPO Critical Incident Alarm, Model I, is an instrument designed to give an audible and visual alarm signal in the event of a critical incident to which it is exposed. There will be thirty-one (31) of these instruments installed and several spares located in the various manufacturing buildings in the Chemical Processing Department where there exists any possibility of a critical incident occurring. The instrument is intended as a post or after-the-fact warning device. It will offer no protection prior or leading up to, nor prevent, a critical incident. They are intended to be operated from the 115 V. A.C., 60 C.P.S. emergency line power. The instrument is self-contained, including the radiation detector, and will be calibrated to alarm at 500 mr/hour in a gamma field.

Nearly all nuclear reactors being designed and built today- whether for research, power, or productions of fissionable materials- use recirculating fluids for cooling. However, a number of production reactors are still operating with single-pass cooling by treated natural water. The Hanford Atomic Products Operation of the General Electric Company presently operates production reactors for the AEC at Richland, Washington. The first reactors were built during World War II, and utilized a standard water treatment which was designed to provide large quantities of settled, filtered Columbia River water for once-through cooling.