as fenders, compartmentalization (perhaps double hulls), and guaranteed 

 reserve buoyancy in case of flooding. A progressive failure mode must 

 be avoided. 



4. Fire Safety . The material and structure should be highly resistant 

 to damage by fire and capable of limiting the spread of fire. 



5. Durability . The construction material (the concrete itself and 



the embedded reinforcing and prestressing steel) must have the long-term 

 capability to resist degradation below a specified standard in the marine 

 environments of atmospheric zone; splash zone* shallow water submerged zone* 

 deep water submerged zone* and, for the anchor, near the seafloor zone and 

 under the seafloor zone. 



6. Long-Term Engineering Properties of Materials . The engineering 

 properties of the construction material must be known over long-term 

 exposure to the marine environment. This includes the behavior of con- 

 crete materials in the stages of partial and complete saturation with 

 seawater. 



7. Maintainability and Repairability . To provide long-term reliability 

 and economy, the need for structural maintenance and repair must be 



minimized; at the same time, inspection, maintenance and repair 



capabilities must be available in order to detect, prevent, control and 

 overcome material degradation that does occur. Some, but not all, OTEC 

 concepts use a modular design to permit periodic removal and replacement 

 of major modules to reduce downtime and permit shipyard overhaul and 

 refit, particularly the heat exchangers; this modularity requires methods 

 for at-sea assembly and disassembly of major structural components ,LJ 

 Some concepts visualize that remote replacement of the critical anchor-to- 

 mooring line connection, on a scheduled or as needed basis, will be 



