a sink for other power plant cooling requirements. The relatively small 

 diameter of the cylinder also reduces the area of shielding necessary for 

 personnel occupancy. The conversion machinery located immediately above 

 the reactor is close to the heat source and attenuates radiation to the control 

 area. The control area is at the maximum distance from radioactive sources in 

 the cylinder. The vertical cylinder arrangement is, in general, preferable for 

 deployment on the ocean bottom due to its hydrodynamic characteristics, its 

 small area of contact with the bottom, and its stability. 



This conceptual arrangement is designed on the basis that a single 

 turbine generator set will be used for the 30-kw or 100-kw plant. The 300-kw 

 plant will probably require two 150-kw horizontal units to fit within the hull 

 diameter, or one single vertical unit, or a high-speed, high-frequency unit. 

 Since a 300-kw plant will require a larger hull for heat transfer than the 30-kw 

 or 100-kw plant adequate space is available for any of the three alternative 

 300-kw arrangements. A steam turbine generator in the low power-level range 

 with compact size, low weight, and good performance is not an off-the-shelf 

 item. 



Waste heat is transferred from the power plant primarily by the turbine 

 exhaust steam condensing directly on the inside surface of the pressure hull. 

 There are many problem areas to be resolved and experimental data that must 

 be obtained to ensure the feasibility of the hull as a heat transfer surface. The 

 provision and testing of reliable protective coatings are required on the 

 seawater side of the hull for high thermal conductivity and high resistance to 

 fouling. 



There are two other heat removal systems within the power plant 

 which do not appear to pose any development problems. The freshwater 

 machinery-cooling system rejects its heat to the shield water, and an air 

 conditioning system for the plant control systems rejects the heat through 

 the hull via direct contact with plastic channels bonded to the hull. 



The 1,000-kw and 3,000-kw plants are arranged in a horizontal 

 cylinder, as illustrated in Figure 3. This arrangement would have features 

 similar to the smaller plants. Some additional problems are noted for the 

 larger plants. A vertical arrangement is possible at shallow depths, but there 

 is little difference in plant size or cost between the vertical and horizontal 

 arrangements for the large plants. However, to ensure adequate natural con- 

 vection heat transfer from the core, a high-power reactor is generally oriented 

 permanently in one direction once it has been operated. It must also be 

 transported in the same orientation. 



At these power levels, the pressure hull required to house the 

 equipment is inadequate as a sufficient heat transfer area. The conventional 

 method for removing waste heat from the hull is to use a heat exchanger piped 



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