life which could cause obstruction and interference problems. The Lockheed 

 design has removable power modules, each of which contains an evaporator 

 and condenser and related warm water and cold water outlets. The need for 

 periodic underwater maintenance of these structures should be diminished 

 because the removable modules can be refurbished in dry dock. The cold 

 water outlet is located below 90 m in depth where fouling accretion is not 

 expected to be of serious consequence. No further consideration need be 

 given to the underwater maintenance of the cold water exhaust. The upper 

 portion of the Lockheed renewable modules contain the evaporator and warm 

 water exhaust which is about 60 m below the surface. More fouling is 

 expected here than at the cold water exhaust, but the high velocity and 

 open discharge (no screens) should keep fouling within reasonable bounds. 

 No underwater maintenance is projected for the ducts of water exhausts of 

 this design because these surfaces also could be cleaned at dry dock. The 

 critical surfaces that do require attention are the exterior and interior 

 surfaces of the warm water inlet screens and the ducts leading to the 

 evaporator intake. Fouling can be removed in a routine fashion using the 

 system described in the subsequent section together with the conceptualized 



mechanical aids for access to the screens and ducts. The conceptualized 



118 

 defouling techniques are directed toward the Lockheed model because it 



is in a more advanced state of geometric definition. While the same 

 approach can apply to other models such as the TRW base line configuration, 

 the dimensions of warm water inlet and warm and cold water exhausts of that 

 design and the depth at which they are located, respectively, are not yet 

 clearly defined. If the ducts are not large enough to be cleaned by multi- 

 brush vehicles, remote control cleaning operations will be required; the 

 apparatus would be positioned by the divers at the time of use. Internal 

 rails could be required to guide the movement of the cleaning device. Of 

 necessity, this would be a more complex system; it would require engineer- 

 ing development of an underwater device equipped with a rotary brush or 

 multihydraulic jets. In general, the mechanical defouling procedure in the 

 warm water intake will scatter debris in a quantity proportional to the 

 amount of fouling. This material must be contained to prevent ingress to 

 the heat exchanger when the plant is restarted after cleaning. Methods to 

 contain and remove the resultant debris will be addressed. 



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