Research Projects

Mechanisms of nutrient turnover in the sea.

Some recent evidence indicates that the passage of a hurricane across the ocean drives surface water out from the storm center in all directions. This, too, produces upwelling. If radionuclides fall on the Arctic ice pack or on the Greenland or Antarctic ice caps, it may be years before they are released to the sea. In more or less stable conditions at sea, radionuclides may remain trapped abovethe thermocline (a layer of sharp temperature change usually less than 100 meters below the surface) for a considerable period. Then a severe storm may destroy the thermocline and mix the waters to much greater depths. The process of diffusion in the ocean is not well understood, due both to the difficulty of the measurements that have to be made and to the variety of other factors affecting both vertical and horizontal transport of materials. Here again, however, the existence of radionuclides, introduced artificially at a known time and place, is materially aiding these investigations by making a particular water mass detectable and traceable.

Winds of 100 knots (about 115 mph) whip high waves in the Caribbean Sea east of Guadeloupe Island during a hurricane.

In chemical oceanography, the AEC is concerned with the fact that in some instances our society is introducing elements, ions, and compounds that have not been naturally found in the sea, as well as natural materials in greater concentration than is normal. These may combine with other materials in the sea, changing into new forms or substances, or removing them from solution entirely. Any change in the chemical composition of the ocean is quite likely to have biological effects, some of which may prove detrimental to man.

A disturbance of the chemical balance of the sea is thought to be responsible, at least in part, for the periodic, disastrous plankton “blooms” known as “red tides”. Such a sudden, explosive overpopulation of plankton is a natural phenomenon, but one that can be triggered by man-made pollution. When it occurs, plankton multiply so rapidly thatthe oxygen in the water is depleted and many fish die from suffocation.

Fortunately, nuclear energy operations account for an extremely small portion of the chemical contamination of the sea, when contrasted with the tremendous volume of poisons dumped daily into it in the form of other industrial and municipal waste and agricultural pesticides.

The AEC supports oceanographic research conducted by its own laboratories and by other federal agencies, as well as by non-government research scientists. The Environmental Sciences Branch of the Division of Biology and Medicine has begun the long and complex task of unraveling the mystery of the fate of radionuclides in the ocean. Valuable techniques have been developed for the intentional injection of radioisotopes into the sea for specific research. Scientists are now able to conduct investigations that were never before possible. In some instances, traditional scientific concepts and theories have been shattered, or at least severely shaken, by new evidence gathered by radioisotope techniques.

Since 70% of the earth’s surface is water, at least 70% of the radioactive debris lofted into the stratosphere during atmospheric nuclear weapons tests falls into the ocean. An additional small proportion finds its way into the sea as the run-off from the land. In the case of tests at sea, the majority of radiation immediately falls into the water nearby. For this reason, the ocean around the sites in the Marshall Islands where U. S. tests were conducted has provided a unique opportunity to study the effect of large concentrations of radionuclides. Particularly significant studies have been conducted of the absorption of radionuclides by plants and animals living on nearby reefs and islands, and of both lateral and vertical diffusion rates of elements in the open ocean.[8]

The 1954 nuclear test at Eniwetok Atoll produced heavier-than-expected local radioactive fallout. Since then, bothAmerican and Japanese scientists have studied water-mass movement rates, using the fallout radionuclides strontium-90 and cesium-137 themselves as tracer elements. These nuclides produced in the test have been detected at depths down to 7000 meters in the far northwestern Pacific in the vicinity of Japan.

Autoradiograph of a plankton sample collected from a Pacific lagoon a week after a 1952 nuclear test, showing concentration of radioisotopes (bright areas).

If this results from simple eddy diffusion, as some scientists believe, it is a case of diffusion at a very high rate. Other scientists suggest that other factors may have contributed to the vertical transport of the radionuclides to these depths. Still others believe that the strontium-90 and cesium-137 might not have originated with the U. S. Pacific tests at all, but rather with Russian tests in the Arctic taking place at about the same time. They propose the theory that a syphoning effect in the Bering Strait causes a current to flow out of the Arctic Ocean and down under the surface waters of the western Pacific. In support of this, Japanese researchers cite a dissolved oxygen content where these measurements were made that is different from that of other deep water in the area. If this theory should be proved correct, it would be the first indication that such a current exists.

Similar investigations have been conducted of the variations in depth of strontium-90 concentration in the Atlantic Ocean. In February 1962, when fallout from 1961 nuclear tests was high, tests south of Greenland showed that mixing of fallout was fairly rapid through the top 800 meters of water. At greater depths a colder, saltier layer of watercontained only about half as much strontium-90, confirming other evidence that interchange between water masses of different physical and chemical properties is comparatively low.

Work such as this has emphasized the difficulty in making meaningful measurements of man-made radiation in the ocean. One problem is to separate the artificially produced radiation from the natural radiation, namely that from potassium-40 (which accounts for 97% of oceanic radiation) and from the radionuclides, such as tritium, carbon-14, beryllium-7, beryllium-10, aluminum-26, and silicon-32, created in the stratosphere naturally by cosmic-ray bombardment.

In 1955 a scientific team aboard the U. S. Coast Guard vesselRoger B. Taneyconducted a survey of ocean fallout in the western Pacific. They collected marine organisms and water samples at various depths on their 17,500-mile, 7-week journey.

Another problem is the sheer physical size of the water sample required to get any measurements at all. Up to now there has been no truly effective radiation counter that can be lowered over the side of a ship to the desired depth. It isoften necessary to collect a sample of many gallons at great depths and return it to the surface without its being mixed by any of the intervening water. This is difficult at best, and only rather primitive methods have been developed. None is more than partly satisfactory. A standard system is to lower a large, collapsed polyethylene bag to the desired depth, open it, fill it, and close it again, all by remote control, and then gingerly and hopefully return it to the surface. Results do not always agree among samples taken at the same location by different methods or by different scientists. There is still no universal agreement among scientists as to the quantitative validity of any of the measurements, although as more and better data are gathered there tends to be a greater concurrence.

Fifty-gallon sampler ready to be lowered over the side of the research vesselAtlantis IIin the North Atlantic. Such devices are used to obtain samples at fixed intervals from the sea surface to the bottom. The water is analyzed for radioisotope content.

Recently, under an AEC contract, a detector for direct measurements of gamma radiation[9]in the deep ocean was developed for the Institute of Marine Sciences, Universityof Miami, by the Franklin GNO Corp. (See figure above.) This unit incorporates two of the largest plastic scintillation counters[10]ever used in the ocean—each is 16 inches in diameter by 12 inches thick. This apparatus may permit direct qualitative and quantitative measurement of radiation at great depths by techniques that will be eminently more satisfactory than water sampling. Already tests with the detector have disclosed the existence of cosmic-ray effects at much greater depths than heretofore known.

Scintillation counter for use in the deep ocean.

Constituent parts. The plastic discs are the radiation detectors.

Biologists from Woods Hole Oceanographic Institution in Massachusetts for the first time have been able to measure the rate of excretion of physiologically important fallout radionuclides by several species of zooplankton—pteropods,pyrasomes,copepods, andeuphausids. Radioactive zinc and iodine, it was learned, are excreted as soluble ions, while iron and manganese appear as solid particles. However, the extent to which the intake and excretion of radionuclides and the vertical migration of zooplankton contribute quantitatively to the transport of radioactivity across the thermocline (and into the ocean deeps) still can only be guessed.

Zooplankton, mostly copepods, collected with automatic underwater sampling equipment on board the nuclear submarineSeadragonwhile cruising under the Arctic ice.

Other plankton research at Woods Hole uses radioactive carbon-14 and phosphorus-32 as tracers to evaluate rates of growth and nutrient assimilation by algae (floating green plants). These investigations have revealed that the presence or absence of minute quantities of nutrient minerals in seawater affects the rate at which the algae produce oxygen by the process of photosynthesis. Since the energy of all living things—including man—is also made available by photosynthesis, and since most of the photosynthesis on earth is performed by algae afloat in the oceans, it isapparent that this research is of more than academic interest. Algae, the original energy-fixers of the “meadows of the sea”, are also the original food source for the billions of aquatic animals, and may some day prove a source of food for a mushrooming human population.

In a project with more immediate application, extensive biological and environmental studies of the Eniwetok Atoll area in the Pacific were conducted prior to the first nuclear testing there in 1948, and these studies have continued ever since. Early in the test series the Japanese, who were at first concerned with the possible contamination of their traditional marine food supplies, were invited to participate in these studies. Fisheries radiological monitoring installations were established in Japan and the U. S. (The latter was established by the AEC and administered by the U. S. Food and Drug Administration.) Neither station encountered any radiological contamination of tuna or other food fish, and the American unit has now been closed.

This shell of the giant clamTridacna gigasshows the position of a layer of strontium-90 absorbed in 1958 (black line) and in 1956 (white line). The inside of the shell (light layers) was deposited in 1964 when the clam was collected at Bikini Atoll by scientists from the University of Washington, Seattle.

Groups that have cooperated with the AEC in marine radiobiological research are the University of Hawaii, University of Connecticut, Virginia Fisheries Laboratory,University of Washington, U. S. Office of Naval Research, and U. S. Bureau of Commercial Fisheries.

At the Bureau of Commercial Fisheries Radiobiological Laboratory in Beaufort, North Carolina, a cooperative effort of the AEC and the BCF is concerned with learning the effects of radioactive wastes on one of America’s most valuable marine resources—the tidal marshlands and estuaries that are essential to the continued well-being of some of our important commercial fisheries.

(Reprinted fromRadiobiological Laboratory Annual Report, April, 1, 1964, page 50.)

The project has determined that radionuclides are removed from waters in an estuarine environment by several physical, chemical, and biological means. For example, radionuclides are absorbed in river-bed sediments at a rate varying directly with sediment particle size. Mollusks, such as clams, marsh mussels, oysters, and scallops, not only assimilate radionuclides selectively, but do so in sufficient quantity and with sufficient reliability to be useful as indicators of the quantity of the isotopes present. Clams and mussels are indicators for cerium-144 and ruthenium-106, scallops for manganese-54, and oysters for zinc-65 (most of which winds up in the oyster’s edible portions). It was learned that scallops assimilate more radioactivity than any other mollusk. Of the total radioactivity, manganese-54 accounts for 60%: The scallop’s kidney contains100 times as much manganese-54 as any of the other tissues and 300 times as much as the muscle, the only part of the scallop usually eaten in this country.

On the left are mussels collected near the Columbia River in an environment containing abnormal amounts of zinc-65.

Mussels suspended in seawater in research to determine how fast they lose their zinc-65 radioactivity.(Photograph taken at low tide.)

In a surprising unintended result, it was determined that one acre of oyster beds, comprising 300,000 individual oysters, may filter out the radionuclides from approximately 10,000 cubic meters (18 cubic miles) of water per week!

The Radiological Laboratory scientists also have found that plankton are high concentrators of both chromium-51 and zinc-65, and that zinc apparently is an essential nutrient for all marine organisms. Some plants and animals appear to reach a peak of radionuclide accumulation quickly, which then tapers off even though the radiation concentration in the water is unchanged.

While the AEC’s oceanographic research budgets have not been large, they have contributed materially to knowledge of the oceanic environment. AEC-sponsored research at Scripps Institution of Oceanography has determined by a process known as neutron activation analysis[11]that the concentration of rare earth elements in Pacific Oceanwaters appears to be only about one hundredth of the level previously reported. By analysis of naturally occurring radioisotopes, they have also discovered that it takes from one million to 100 million years for lithium, potassium, barium, strontium, and similar elements introduced into the ocean from rivers to be deposited in the bottom sediments. Aluminum, iron, and titanium are deposited in from 100 to 1000 years. They have also found that sedimentation occurs in the South Pacific at a rate of from 0.3 to 0.6 millimeter per thousand years, in the North Pacific at a rate several times that figure, and in the basins on either side of the Mid-Atlantic Ridge at a rate of several millimeters per thousand years.

The University of Miami has successfully developed two methods for determining the ages of successive layers of deep ocean sediments based on the relative abundances of natural radioelements, and thereby has established a chronology of climatic changes during the last 200,000 years during which the sediments were laid down.

The U. S. is not alone in its use of nuclear energy as a tool of science. The United Kingdom has carried out radiological studies of the marine environment for many years, particularly concentrating on the effects of radionuclides from nuclear power plants on the sea immediately contiguous to the British Isles. Both the European Atomic Energy Community and the International Atomic Energy Agency also encouraged marine radiological studies. Many laboratories and government agencies in Europe, North and South America, Africa, and the Middle East and Far East have well-established and productive programs under way.

Scientists in many parts of the world have used both natural and intentionally injected radiation to study the coastwise movement of beach materials. British experimenters, for example, activate sand with scandium-46 and are thus able to follow its movement for up to four months. Pebbles (shingle) coated with barium-140 and lanthanum-140 are also used as tracers and are good for 6 weeks. Scientists at the University of California trace naturally occurring radioisotopes of thorium, which may be introduced from deposits of thorium sands along river banks. These studies are of immediate practical importance, for eachyear the ocean moves billions of cubic yards of sand, gravel, shingle, and rock to and from beaches and along shores. This action destroys recreational beaches, fills channels, blocks off harbors, and in general rearranges the terrain, often at considerable cost and inconvenience to mariners and other people who use the coast.

In another use of radioisotopes in marine research, studies at the AEC’s Oak Ridge National Laboratory in Tennessee have revealed radioactivity in the scales of fish taken from waters affected by the laboratory’s radioactive waste effluent. It was suggested that this phenomenon might be put to use as a tagging technique in fish-migration studies, and scientists are now working on a method using cesium-134 introduced into the fishes’ natural diet.

Isaacs-Kidd midwater trawl collects samples of oceanic animals off the Oregon Coast. These animals are then radioanalyzed to compare the quantity of radioisotopes associated with animals from various depths. The recorder at the trawl mouth indicates the volume of water filtered.

Some of the most extensive studies of a marine environment ever conducted are those by the AEC, the Bureau of Commercial Fisheries, and the University of Washington in the Columbia River system and the nearby Pacific Ocean. Operations at the AEC’s giant Hanford facilities some 300 miles upstream from the ocean result in the release of small amounts of radioactivity to the river and also in raising the river-water temperature. This downstream research is to determine any effects of these changes,including any that might be detrimental to man. The research encompasses studies of the variations and distributions of the freshwater “plume”—the outflow from the rivermouth—extending into the nearby Pacific, sediment analyses, studies of the population dynamics of phytoplankton, and the transport of radionuclides through the food chain.

This core sampler is used to obtain stream bed samples up to 5 feet long in the Columbia River. The samples are then analyzed for radioisotope content.

As so often happens with basic programs, this research has produced immediate benefits. New resources of marketable oceanic fish were discovered by the scientists at depths never before fished commercially (from the edge of the continental shelf to depths of 500 fathoms and greater). Similarly, commercial quantities of one species of crab have been discovered in the deeper ocean. Other findings indicate that crab populations may have seasonal up-and-down migrations that vary according to sex. It appears, in fact, that, except while mating and as juveniles, the male and female crab populations lead separate lives. This information is important both for more efficient fisheries and for improved conservation of the crab as a food resource.

The AEC is, in short, concerned with virtually every facet of basic oceanography, and with study of the sea as a whole, for radionuclides, like their nonradioactive counterparts, can and do become involved in every phase of the vast and complex ocean ecology. In the process of pursuing its research interests, it also provides oceanographers with a whole new family of tools for study. Let us now see how atomic instruments contribute to the growing knowledge of the sea.

This radioisotope powered swimsuit heater uses plutonium-238 to produce 420 watts of heat. Water, heated by the decay of ²³⁸Pu, is pumped through plastic veins partially visible in the undergarment. The cylinder under the diver’s arm contains 4 capsules of ²³⁸Pu, and a battery-pump assembly is contained in the box at his feet. After preliminary tests at the Naval Medical Research Institute in Bethesda, Maryland, the unit will be used in Sealab III, the Navy’s underwater research laboratory. The heater was developed by the AEC Division of Isotopes Development.

The ocean is both a complex and a harsh environment and its study has always demanded that designers of seaworthy instruments and sampling devices be both ingenious and experienced in shipboard requirements. Until recently,these devices tended to be rugged and simple, if not indeed crude. More refined, electronic instrumentation has begun to appear in recent years, but most designs still fail to pass the test of use at sea. Even among those that do pass, there is persistent difficulty in separating desired information-carrying signals from background and system-induced “noise”. This has been a specific problem with current meters designed to be moored in the open ocean and also with one quite sophisticated gamma-ray detector.

To meet the clear need for improved devices, as well as to support its own research and increase utilization of nuclear materials and techniques, the AEC Division of Isotopes Development encourages the development of oceanographic instrumentation. This comparatively young technology already has produced exciting results. The future may be even more revealing as nuclear energy is applied more and more to the study, exploration, and exploitation of the ocean.

Instruments that have been developed under the AEC program include a current meter, a dissolved-oxygen-content analyzer, and a sediment-density meter. A new, fast method for determining the mineral content of geological samples also has been perfected.

TheDEEP WATER ISOTOPIC CURRENT ANALYZER(DWICA) was developed under a contract with William H. Johnson Laboratories, Inc. It relies on radioisotope drift time over a fixed course to measure seawater flow rates ranging from 0.002 to 10.0 knots. The device embodies 12 radiation sensors spaced equally in a circle around a radioisotope-injection nozzle. Current direction can be determined to within 15 degrees. The mass of tracer isotope injected is very small—less than 10 picograms[12]per injection—and the instrument can store enough tracer material to operate for a year. The tracer can be injected automatically at intervals from 2 to 20 minutes, depending on the current. The device sits on the sea floor, where its orientation to magnetic north can be determined within 2.5 degrees.

The Deep Water Isotopic Current Analyzer.

ASEDIMENT DENSITY PROBE, developed under an AEC contract by Lane-Wells Company, employs gamma-ray absorption and backscatter properties[13]to determine the density of the sediments at the bottom of lakes, rivers, or the ocean, without the necessity of returning a sediment sample to the surface. It is expected that it can be modified to sense the water content of the sediments. These determinations are valuable not only for research, but also for activity that requires structures on the ocean floor, such as petroleum exploration and naval operations.

The Sediment Density Probe. The drawing shows the complete probe.

The unit consists of a rocket-like tube 26 feet long and about 4 inches in diameter, containing a gamma-ray-emitting cesium-137 source, a lead shield, and a radiation detector. The device is lowered over the side of a ship andallowed to penetrate the sediment. Once in place, the gamma ray source, shield, and detector move together up and down, inside the probe, for a distance of 11 feet, stopping every 24 inches for 4 minutes to take a measurement. Gamma rays are absorbed in any material through which they pass, according to its density. A low radiation count at the detector indicates a high-density sediment: More radiation is absorbed and less is reflected back to the detector. Conversely, a high count indicates low density. Data are recorded on special cold-resistant film. A number of different sediment measurements can be made in several locations before the unit must be returned to the surface.

Oxygen analyzer equipment includes the deep-sea probe (large device, center, including a special Geiger counter, the electronic assembly, a pump, and power supplies), cable for transmission of Geiger counter signals (back), and portable scaler (left).

The latter is also shown aboard a research vessel (inset) during tests made at sea.

OXYGEN ANALYZERThe amount of dissolved oxygen in any part of the ocean is a basic quantity that must be determined before some kinds of research can be undertaken. For example, oxygen concentration is important in determining the life-support capability of seawater and inmeasuring deep-water mixing. In the past this measurement has had to be determined by laborious chemical methods that may subject the water sample to contamination by exposure to atmospheric oxygen. Under an AEC contract, the Research Triangle Institute has developed a dissolved oxygen analyzer that relies on the quantitative oxidation by dissolved oxygen of thallium metal containing a known ratio of radioactive thallium-204.

The seawater sample passes through a column lined with thallium. The thallium is oxydized and goes into solution. It then passes between two facing pancake-shaped radiation counters that record the level of beta radiation from the thallium-204. Since the rate of oxidation, and therefore the rate of release of the thallium to solution, is proportional to the amount of dissolved oxygen in the water, it is simple to calibrate the device to show oxygen content. The system is sensitive enough to detect one part of oxygen in 10 billion of water. And, the device can be towed and take readings at depths of up to one mile, an added advantage that obviates the chances of surface-air contamination.

NEUTRON ACTIVATION ANALYSISNuclear energy is contributing to the more accurate and more rapid analysis of minerals in the sea in at least two different ways. The first employs neutron activation analysis, which we have already mentioned. This method is valuable not only in analyzing sediments cored from the ocean floor, but also in the detection and quantitative analysis of trace elements in the water. Knowledge of the role of all natural constituents in the ocean is essential to an understanding of the complex interrelationships of the ocean environment, as we have seen. Identification of trace elements also is a necessary preliminary to determining the effects of purposely introduced radionuclides. Collection of the minute quantities of trace elements is very difficult at best. Once they have been collected and concentrated, neutron activation analysis provides a means for their identification and measurement.

X-RAY FLUORESCENCEis another technique, used to identify the mineral content of ore or sediment. This systemwas developed (for the purpose of spotting gold being smuggled through Customs) by Tracerlab Division of Laboratory for Electronics, Inc. (LFE), under an AEC contract. Similar equipment was developed simultaneously in England for use by prospectors, geologists and mining engineers. It now may be used at sea in analyzing samples from the sea floor. As is often the case with isotope-based devices, its operation is really quite simple. When excited by radiation from an isotope (or any other radiation source), each element produces its own unique pattern of X-ray fluorescence, that is, it radiates characteristic X rays. By varying filters and measuring the count rate, oceanographers can detect and measure materials, such as tin, copper, lead, and zinc. The British unit is completely transistorized, battery powered, and weighs only 16.5 pounds.

RHODAMINE-B DYEThe AEC also has improved oceanographic research in ways that do not involve the use of nuclear energy. Some years ago under the joint sponsorship of the AEC Division of Reactor Development and Technology and the Division of Biology and Medicine, the Waterlift Division of Cleveland Pneumatic Tool Company developed instrumentation and techniques for detecting the presence of the red dye, rhodamine-B, in concentrations as low as one-tenth part per billion. This method is now widely used both for groundwater studies and in the study of currents, diffusion, and pollution in rivers, lakes, and the ocean. In many cases, rhodamine-B is a better tracer in water than radioisotopes, due to the greater ease with which it is detected.

The AEC Division of Reactor Development and Technology has supported extensive environmental studies to assess the safety of isotopic power sources (to be discussed later) in oceanic environments. One of the most important of these is being conducted by the Naval Radiological Defense Laboratory at an ocean environmental testing complex near San Clemente Island off the coast of California, which includes a shore installation and a floatingocean platform. These studies are to determine seawater corrosion of containment alloys and fuel solubility in seawater; the dispersion of the fuel in the ocean; the effect of the radioactive material on marine life; and the radiation hazard to man, when all significant exposure pathways are considered.

In another study the Chesapeake Bay Institute of Johns Hopkins University investigated potential hazards that might result if radioactive materials were released off the Atlantic Coast. Five areas along the Continental Shelf were examined in detail for environmental factors such as vertical diffusion. The same Institute made environmental and physical dispersion studies off Cape Kennedy, Florida, to predict the fate of any radioactive materials that might be released in aborted launchings of nuclear rockets or nuclear auxiliary power devices for space uses. Fluorescent dye was released into offshore, surf zone, and inshore locations; the diffusion was observed, sampled, and compared with existing diffusion theory. Mathematical models have been developed that can now be used to predict the rate and extent of diffusion in the Cape Kennedy area in the event of any radioactivity release from aborted test flights.

Similar studies have been carried out near the space launching site at Point Arguello, California, by the Scripps Institution of Oceanography. These included collection of data on dispersion, marine sediments, and the biological uptake of radioactive plutonium, polonium, cesium, and strontium.

NUCLEAR REACTOR PROPULSION

The transformation in undersea warfare tactics and national defense strategy effected by the introduction of nuclear-powered submarines is now well known. Navy submarines employing the latest reactors and fuel elements can stay at sea for more than 3 years without refueling.Polarissubmarines on patrol remain submerged for 60 to 70 days. The nuclear submarineTriton, tracing Magellan’s route of 400 years earlier, traveled 36,000 miles under water, moving around the world in 83 days and 10 hours.Under-ice transits of the Arctic Ocean by nuclear submarines are now commonplace. These feats all are possible because of the nuclear reactors and propulsion systems developed by the AEC Division of Naval Reactors, which also developed the propulsion plants for the Navy’s nuclear surface vessels.[14]

USSSeadragonandSkatesit nose to nose on top of the world after under-ice voyages from the Atlantic and Pacific Oceans to the North Pole.

A frogman from the Seadragon swims under the Arctic ice in one of the first photographs made beneath the North Pole.

DEEP SUBMERGENCE RESEARCH VEHICLEOn April 18, 1965, President Johnson announced that the Atomic Energy Commission and Department of the Navy were undertaking development of a nuclear-powered deep submergence research and engineering vehicle. This manned vehicle, designated the NR-1, will have vastly greater endurance than any other yet developed or planned, because of itsnuclear power. Its development will provide the basis for future nuclear-powered oceanographic research vehicles of even greater versatility and depth capability.

The NR-1 will be able to move at maximum speed for periods of time limited only by the amount of food and supplies it carries. With a crew of five and two scientists, the vehicle will be able to make detailed studies of the ocean bottom, temperature, currents, and other phenomena for military, commercial, and scientific uses. The nuclear propulsion plant will give it great independence from surface support ships and essentially unlimited endurance for exploration.

The submarine will have viewing ports for visual observation of its surroundings and of the ocean bottom. A remote grapple will permit collection of marine samples and other objects. The NR-1 is expected to be capable of exploring areas of the Continental Shelf, which appears to contain the most accessible wealth in mineral and food resources in the seas. Exploratory charting of this kind may help the United States in establishing sovereignty over parts of the Continental Shelf; a ship with its depth capability can explore an ocean-bottom area several times larger than the United States.

The reactor plant for the vehicle is being designed by the General Electric Company’s Knolls Atomic Power Laboratory, Schenectady, New York. The remainder of the propulsion plant is being designed by the Electric Boat Division, General Dynamics Corporation, Groton, Connecticut.

Scientists are already beginning to implant small sea floor laboratories. In the future, when large permanent undersea installations for scientific investigation, mining, or fish farming become a reality, nuclear reactors like the one designed for research submersibles or the one already in use in Antarctica and other remote locations[15]will serve as their power plants.

ISOTOPIC POWER SOURCES

The ocean is a logistically remote environment, in the sense that conventional combustible fuels can’t be used underwater unless supplied with their own sources of oxygen. It is usually extremely costly to take anything heavy or bulky into the deep ocean. Even if the two essential components of combustion—fuel and oxygen—could be delivered economically to an undersea base or craft, the extreme back pressure of the depths would present serious exhaust problems. Yet deep beneath the sea is just where we now propose to do large amounts of work requiring huge supplies of reliable energy. The lack of reliable and extended duration power sources is perhaps one of the most critical requirements for expansion of underwater and marine technology. For example, the pressing need for measurements of atmospheric and oceanic data to support scientific, commercial, and military operations will in the future require literally hundreds of oceanographic and meteorological buoys deployed throughout the world to take simultaneous measurements and time-series observations at specific sites.

Some of these buoys will support and monitor up to 100 sensors each. These devices record a variety of physical, chemical, and radiological phenomena above, at, or below the surface. Periodically the sensor data will be converted to digital form and stored on magnetic tape for later retrieval by distant shore-based or shipboard radio command, by satellite command (for retransmittal to ground stations), or by physical recovery of the tapes. Individually, each buoy will not require a great deal of energy to operate, but will have to operate reliably over long periods of time. Conventional power sources are being used for the prototype buoys now under development and testing, but these robot ocean platforms in the future will make excellent use of nuclear energy supplied by isotopic power sources.

The world’s first nuclear-powered weather buoy located in the center of the Gulf of Mexico. This weather station, part of the U. S. Navy’s NOMAD system, is on a barge 10 feet × 20 feet, and is anchored in 12,000 feet of water.

The SNAP-7D isotope power generator has been operating unattended since January 1964 on a deep-ocean moored buoy in the Gulf of Mexico. This U. S. Navy NOMAD (Navy Oceanographic and Meteorological Automatic Device) buoy is powered by a 60-watt, strontium-90 radioisotope source, which was developed by the AEC Division of Reactor Development and Technology. This weather station transmits data for 2 minutes and 20 seconds every 3 hours. This data includes air temperature, barometric pressure, and wind velocity and direction. Storm detectors trigger special hourly transmissions during severe weather conditions. The generator operates continuously and charges storage batteries between transmissions. Some power is used to light a navigation beacon to alert passing ships.

Energy from the heat of radioisotope decay has been used on a “proof-of-principle” basis in several other instances involving ocean or marine technology.

An experimental ⁹⁰Sr isotope-powered acoustic navigation beacon (SNAP-7E) now rests on the sea floor in 15,000 feet of water near Bermuda. Devices such as these not only will enable nearby surface research or salvage vessels to locate their positions precisely (something very difficult to do at sea) and to return to the same spot, but the beacons also will aid submarine navigation (seepage 48).

A U. S. Coast Guard lighthouse located in Chesapeake Bay has been powered by a 60-watt, ⁹⁰Sr power source, SNAP-7B, for 2 years without maintenance or service. This unit was subsequently relocated for use in another application (described below).

Engineers prepare to install the SNAP-7D generator.

The first commercial use of one of these “atomic batteries” began in 1965 when the SNAP-7B 60-watt generator went into operation on an unmanned Phillips Petroleum Company offshore oil platform, 40 miles southeast of Cameron, Louisiana. The generator operates flashing navigational lights and, in bad weather, an electronic foghorn (seepage 49). This unit will be tested for 2 years to determine the economic feasibility of routinely using isotopic power devices on a commercial basis.

Acoustic pulses.

The SNAP-7E isotopic generator powers an undersea acoustic beacon, which produces an acoustic pulse once every 60 seconds. In addition to being a navigation aid, the beacon is used to study the effects of a deep-ocean environment on the transmission of sound over long distances.

Back to Index Next