Appendix B 

 30-DAY IMMERSION TESTS IN PORT HUENEME HARBOR 



Following completion of the controlled laboratory tests reported in 

 the main body of the report, it was decided to ianerse the unit under 

 power in the Port Huenerae Harbor for a aortth. This additional testing 

 would have several potential benefits: determination of RTG temperature 

 at lower water temperatures than could be readily obtained in the test 

 tank, the incipient formation of biological scum, and the temperature 

 effects of small tidal currents acting across the copper finned heat 

 rejection surfaces. 



The instrumentation for these tests was the same as used in the 

 earlier laboratory tank tests, except that the test unit was fitted with 

 a carefully calibrated Savonius Rotor Current Meter at the same level 

 as the heat transfer surfaces. Figure 20. One thermocouple failed (opened) 

 before any readings were taken, but since it was very expensive to remove 

 the unit from the water and replace, the thermocouple was not repaired.* 



It was originally planned to set the entire RTG on the bottom on a 

 hardwood pallet; a survey of the proposed area by CEL divers indicated 

 suitable near-level areas. However, early attempts to stabilize tne RTG 

 on the bottom showed that the bottom was neither level nor stable within 

 a reasonable distance of the wharf. It was eventually suspended by a 

 heavy synthetic line just off the bottom in about 25 feet of water 

 (Figure 20). The bottom of the RTG was sufficiently close to the harbor 

 bottom to stir up mud upon its retrieval. The heat rejection surfaces 

 were about 19 feet below the water surface at mean tide. 



Typical temperatures taken during the 30-day immersion period are 

 shown in Table 9 with varying currents. In the earlier laboratory tests, 

 the power level was varied from the nominal 32 kw by changing the voltage 

 from a portable generator. In these tests, power output was determined 

 by the CEL dock-side voltage, yielding a heat dissipation of approximately 

 8 kw or about 11% less than the nominal. 



In Table 9 the temperatures taken in the harbor, where the experiment 

 vas exposed to water some 18°F colder than in the earlier laboratory tank 

 tests, are compared with data taken 10 August 1^73 in the tank (last 

 column). All things being equal, it would be expected that typical metal 

 tenperatures in the harbor would be about 18°F colder than in the tank 

 cue to the colder water. Also, the current effect, while probably slight 

 and variable, should be discernible. To allow direct comparison, the 

 temperature differences are increased by the 18°F water temperature 

 difference, Figure 21. 



It was a surface temperature reading in a partially instrumented 

 module a-d was not important in the analysis. 



44 



