120 



Mr. Keinecke. Wlien do you anticipate this 10-kilowatt unit will 

 be available? 



Mr. Seiken. We look to a 3- to 5-year period of development, start- 

 ing from this time. 



Mr. Reinecke. Is it realistic to think that after that you may go to 

 a hundred kilowatts ? 



Mr. Seiken. Yes sir, but not necessarily with isotopes. At the pres- 

 ent time we believe isotope power to offer attractive undersea power 

 capability at a power range of up to 10 or 20 kilowatts. Furthermore, 

 we believe nuclear reactors are feasible and attractive at a power range 

 as low as 100 kilowatts. In between these two limits is a gray area. In 

 certain instances isotopes may be attractive — in others reactors. Much 

 will depend upon the specific mission requirements. 



Mr. Keinecke. Do you envision a sensing system throughout the 

 world as a means of detecting military fallout ? 



Mr. Joseph. Indirectly. I think we can use a synoptic system now, 

 to measure mixing systems — water masses and currents. 



Mr. Reinecke. I believe you mentioned in your paper there was a 

 concentration of cesium in the ocean — I am not sure what — ^but 

 nevertheless, was this sufficiently concentrated to affect the fish? 



Mr. Joseph. No. We have been following concentrations of cesium 

 in various classes of marine organisms from plankton up to the higher 

 trophic levels, and cesium doesn't concentrate in organisms to any 

 degree. It is about a 1-to-l concentration factor in the flesh of marine 

 organisms. 



Mr. Reinecke, I believe you mentioned there is a chemical reac- 

 tion. Does this affect the half life ? 



Mr. Joseph. No. Nothing changes the half life. 



Mr. Lennon. The gentleman from Alabama for 3 minutes. 



Mr. Edwards. Thank you, Mr. Chairman. 



Could you say in layman's terms that radioactivity or radioactivity 

 fallout will wear itself out eventually in the ocean ? 



Mr. Joseph. Eventually, yes. 



By radio activity decay — we use the term "half life." A given 

 amount of radioactive substance will lose half of its activity in the 

 period of the half life, but the half life varies with the isotope in- 

 volved. And this can be anywhere from a microsecond — a millionth of 

 a second — ^on up to — oh, some of the longer lifed isotopes are of 

 the order of 10 to the 10th power years — 10,000 years. 



Mr. Edwards. That is layman's language ? [Laughter.] 



Mr. Joseph. A rule of thumb we use is that a given amount of 

 radioactivity will decay to one-tenth of 1 percent of the original 

 amount you started with in a period of 10 half lives. 



Mr. Edwards. I guess what I am getting at is that over a period of 

 years, as we get more and more involved with nuclear power and 

 what-not, there will be more and more radioactive substances falling 

 into the ocean. 



Is it there forever ? Are the fish that are in the ocean over a period 

 of years going to become more and more saturated with radioactive 

 material ? Is this a real problem ? 



Mr. Joseph. Let me answer your question this way, if I may. 



I j)articipated in a recent expedition to Bikini to measure radio- 

 activity in the Bikini and Eniwetok testing grounds. During the test- 



