Fresh water was used for cooling the jackets of each engine, in a closed circuit consisting of the engine jackets, closed heat exchanger, pump and piping. Salt water was used to remove the heat from the fresh water, and then wasted. Installation and piping of all units was con- ventional, and the recommendations of Fairbanks-Morse and of Cleaver Brooks, who furnished the water distillation units, were followed in detail, Holmes & Narver and AEC representatives agreed that automatic voltage regulation of the primary distribution system would not be satisfactory because of the different requirements of the various Users. Some Users could operate on plus or minus 10 volts variation, while for other Users the value of the secondary voltage was very critical, Accordingly, it was decided that Users whose voltage requirements were critical would incorporate regulators in their equipment design. In this way it was believed that the over-all cost would be lower and the results much more dependable, The use of small individual regulators proved to be very satisfactory. Fluctuation in voltage such as that caused by simultaneous starting of seven motors in the control tower (Building 310) on Parry Island were corrected by the installation of additional transformers and by balancing the circuits to the power house, In general, the application and removal of large loads which might affect the voltage and the frequency were correlated so that the minimum system disturbance occurred, Prior to February and March of 1951, no specific requirements as to frequency had been received. During February amd March 1951, fre- quency requirements were developed, the most exacting being that of E G & G who asked for an error of less than 1.0 second in the fifteen minute interval prior to H-hour, This corresponded to 0.111 per cent average error, PLANT. DESIGN The Reconnaissance Report indicated the number, location, and capacity of power plants then proposed for the Project (see Plate 22, Appendix A, of the present report), Table 5.15-1 shows the number, location, capacity and use of power plants as installed and Figure 5.15-1 shows pictorially the number, location, and capacities of plants. A brief chronology of engineering activities leading to the final selection of generator units, types of buildings and mechanical arrangements follows, I . The Reconnaissance Report based upon criteria then available predicted a maximum population for Eniwetok Island of 600 personnel and a maximum electrical demand of 425 kw Supplement No, 1 to the Reconnaissance Report estimated population at between 600 and 2,200, as at that time it was believed that more people would be housed on Eniwetok than the original estimate of 600, although the number was not known, The increase in population, whatever the number, was to be housed in tents, On this basis the increase in power demands would not 5-204