The Effects of Atomic Radiation on Oceanography and Fisheries (1957) / Chapter Skim
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ON THE TAGGING OF WATER MASSES FOR THE STUDY OF PHYSICAL PROCESSES IN THE OCEANS
ON THE TAGGING OF WATER MASSES FOR THE STUDY OF PHYSICAL PROCESSES IN THE OCEANS
Pages 121-132
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From page 121... ...
It is not generally realized how much experience has been gained, beginning with the 1946 tests in Bikini Lagoon, in tracing water masses contaminated with radioactive materials from weapons' tests. And many thoughts are now turning toward the radioactive tagging of ocean water by other means in regions where knowledge of underlying physical processes are meager, especially in the very deep waters.
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From page 122... ...
Many aspects of the measurement problem are oversimplified by a comparison of this sort, but the table does indicate that present shipboard beta analysis is capable of measuring beta tracer activity below the background beta activity due to the potassium in the sea water, whereas gamma detectors so far have been limited at levels above the gamma backgrounds of the sea. On surveys covering large distances, such as on Operation TROLL (U.
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From page 123... ...
Deliberate tagging of surface waters (Operation PORK CHOP) Surface waters mix in a turbulent manner due to forces not yet fully understood.
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From page 124... ...
An example of the dispersal rate in the open sea will now be given. Brief outcome of an experimental tagging of surface waters in the open sea Surface water made active by introducing fission products concentrated within a few square kilometers was intercepted by a ship 36 days after inoculation and traversed for 10 days.
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From page 125... ...
A Common background radiation levels: d/m/1 curies/1 microcuries/ml rad/hr2 mrad/yrS Activity in normal sea water due to potassium:1 Gamma rays 70 3 X 10'u 3 X 10-8 1 X 10'1 0.9 Beta rays 660 3.0 X 10'10 3.0X10^ -- -- Maximum permissible 4 concentration of unknown mixed beta activities in drinking water: Beta rays 220 11 X 10'" 1 X 10"* -- -- Cosmic ray background at sea surface: s At equator 61 -- -- -- 33 At 55°N (mag)
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From page 126... ...
3 5 60 180 300 600 .19 .11 .010 .0038 .0049 .0032 11,000 6,600 590 350 290 190 3.7 3.3 .29 .17 .15 .096 17 17 17 32 43 58 6.5 X 10" 3.8 .33 .20 .17 .11 16 XU 9-5 .84 .50 .42 .28 Very large 0.067'/ vT' (c) Minimum detectable concentration if total background were 60 CPM, i.e., an actual background signal experienced at the sea surface.
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From page 127... ...
Ship A or a sister ship with similar gear might stay in the pool during the whole experiment, however, if the pool were lost after its depth was established, then Ship B would likely be the first to find it again with its towed detector. Difficulties in sounding and exploring very deep waters Bottom exploration so far has been confined largely to sonic plotting and sounding by solid cable; very deep wire casts are very time consuming and difficult; the ship generally is moved laterally by surface currents before the OPERATION "POKER CHIP" FIGURE 2
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From page 128... ...
Matching density at intermediate layers or attempting to insert a strata at a selected depth also would appear experimentally difficult in view of the limited knowledge presently available; an unequilibrated liquid mass might wander about like a sinking dinnerplate -- and soon become lost. In the absence of the restraining forces found in more stable waters, the pouring of streams of dense solution downward from a height above the bottom, or alternately the releasing of lighter material upward from the bottom would surely cause mass motion which might not cease until the streams had moved long distances and perhaps had curled into configurations quite unsuited as initial boundary conditions for water tracing experiments.
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From page 129... ...
It would appear that one or more tons of a nitrate salt, mixed into bottom water by use of a few kilowatt hours of energy, stored in oil-sealed accumulators, could produce a compact body of very heavy water which would rush like a freight train across the terrain dropping a streak of traceable radioactive eddies as it traveled. A fixed, water-mixing quern, of the sort described, might produce a tagged water mass behaving in a manner appearing realistic to both the disposal planner and the submarine geologist; however, its use is not likely to lead directly to the extremely simple results needed for the very first experiments.
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From page 130... ...
Rough estimate of effectiveness of 1,000 curies for tagging bottom waters It appears possible to distribute radioactivity uniformly along the course of a device dragged over the sea bottom, and it would appear possible also to deposit the material so gently that it would come to rest within a few meters of the precise course. If, for a rough evaluation, we assume that local diffusion sooner or later produced a uniform distribution within a radius of 10 meters, and that the total activity, M, was 1,000 curies, then the length of the water mass which might be tagged can be stated ship's speed is about 4 knots)
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From page 131... ...
when the background rate is b, and accuracy is, n, the limiting concentration can be expressed, N=A.5 curies/ml, wherein b expresses the background rate actually indicated when the instrument is surrounded by clean sea water. If no other background exists except that coming from a surrounding solution having specific activity B, and if the instrument counts this activity with the same efficiency, e, than the limiting detectable concentration becomes, in curies/ml, N= 2 + 2\/l + Bri-vet 3.7 x 1 A.6 Numerical examples applying to an actual undersea instrument The sensitive portion of the 1955 model of the Scripps Institution of Oceanography's Geiger instrument has a volume of about 1,000 ml.
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From page 132... ...
1953. Maximum permissible amounts of radioisotopes in the human body, and maximum permissible concentrations in air and water.
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