Atoms for power; Oak Ridge experiment

As for far as. A transcribed program produced by producer university under a grant from the Educational Television and Radio Center in cooperation with the National Association of educational broadcaster on today's program written and produced by Bob McMahon will play a visit to the Oak Ridge National Laboratory at Oakridge Tennessee. This is bopping around thinking. I'm talking to you from Oak Ridge Tennessee and out of a city that grew in that to what I have here a period during World War Two a lot of what had been a marginal part of life. It's a busy town of about 30000 people. Nestled in a long narrow valley stretching between two moderately high wooded ridges in the hills of eastern Tennessee. It's located about 20 miles west of Knoxville. To accommodate itself in the West Valley town of about nine miles long and only him about a mile or so wide and in fact. The down of a bridge but that has many of the outward features of a typical I mean really no no mind frame buildings here and there are barracks like dormitory.

But in the last several years the faint of Old Bridge has been changing as the temporary buildings outlive their usefulness and are in permanent schools and homes are going up in their place. Land has been sold to many church groups to build their own buildings and more than two has gotten started or completed permanent structures. Oak Ridge is beginning to look like the typical American community for that's just what it's become. Laboratory which is operated for the Atomic Energy Commission by the nuclear company is often referred to as the largest Nuclear Energy Laboratory in the United States is concerned with development and research in virtually all phases of nuclear energy. The work of the laboratory is divided among six research and seven operating divisions and covers practically all fields of modern technology. Untold area comprises 94 square miles but the central activity of the laboratory revolves about the problems of reactors. We

work here today to see how some of this work is progressing. The nation's electrical consumption can be correlated directly to its national wealth. For example the annual per capita consumption of energy in all forms for India corresponds to 600 kilowatt hours and the per capita income of that country is $50. The corresponding figures for the United States are 12000 kilowatt hours and 2000 dollars. The quantity of installed electric generating capacity in the United States is doubling every 10 years. We can expect that by the year 2000 electrical power consumed per year will have increased 20 times over with this expansion it is very likely that most sources of hydro electric power will soon be exploited and that every nation's capacity to produce coal oil and gas will by then have been strained to the limit and for this reason atomic power now is not only desirable but an absolute necessity. Today the Atomic Energy Commission is

sponsoring a huge undertaking known as the five year power reactor development program to assist in establishing an atomic power industry in our country even though there is no current power shortage here in the United States. We are nevertheless in the process of establishing a huge new atomic power industry. Here are the views of Dr. album M. Weinberg director of the Oak Ridge National Laboratory. As to why this is being done today. There are many reasons for the sense of urgency which permeates the efforts to establish nuclear power as an important industrial undertaking. There is an underlying incentive to create the boon to humanity which successful nuclear power will be. However this in itself is hardly a reason for urgency since Coal power especially in the United States is relatively cheap. But there are predictions such as those of Palmer Putnam that civilization has considerably less than 100

years to develop a substitute for our rapidly dwindling fossil fuels that even by 1975 the requirement for an alternate energy sarce will be very strong. There is a growing realisation that the huge diffusion plant and plutonium producing reactors represent national resources just as surely as do Grand Coulee or boulder dams that if there is any possible long term economic pattern for the ultimate utilization of these precious national properties then by all means we must implement any such possibility. Unfortunately for the development of nuclear power our country which has spent the most on development of both civilian and military nuclear energy has the least immediate need for a new large scale power source because of a remarkable though rather I'm heralded

series of small improvements in conventional power generation practice. Rising costs of fuels have not caused a corresponding increase in power costs. The most modern large scale steam power stations today operate at an overall thermal efficiency of about 37 percent. At many places in this country coal fired steam power is available at three to four mills per kilowatt hour. While these extremely low rates are rather unusual the Countrywide average about five to six mills per kilowatt hour counting all plants are about four to five mills per kilowatt hour counting only plants which have been constructed since 1940 represents the stiffest sort of competition for nuclear power. It has been pointed out that in other countries such as Belgium or England economic realities resulting from a clearly demonstrably coal shortage give to

the immediate and urgent development of large scale nuclear power. The kind of economic sense which only very clever technical achievements can inject into the development in our country. Perhaps it is this last consideration as much as any increase in byproduct military potential which gives to the large scale power reactor development a real sense of urgency. President Eisenhower has made an eloquent taste for widespread peacetime exploitation of nuclear fuel as a touchstone for peace. We in this country have elected to use the development of nuclear energy as a means of furthering the aims of the United States throughout the world. In particular we have decided to use this development as a means of maintaining our influence in the uncommitted countries. Cheap nuclear power if properly developed politically may help in averting the overall disaster. It is this

possibility which gives urgency to nuclear power development and transcends even the lively probability of making cheap nuclear energy a commercial success. One would talk about power of any kind we mean power that can be economically produced so that anyone can afford it. And then considering the economics of atomic power we frequently hear the question when will atomic power be as cheap to produce as power from other sources. Here is Dr. Donald J tend of our scientific advisor from Purdue University to tell us more about the problem. Among the technical factors that contribute to a great extent to the atomic power costs the following stand out more than all the rest. The cost of the fissionable material or a few the cost of fabricating fuel in the proper forms and shapes and the cost of reprocessing partially burned fissionable material to separate the fission products and to recover and burn fuel. Disposal of

radioactive waste products and the general maintenance problems in the reactor and plant every nuclear reactor can operate for only a certain length of time before its fuel must be removed. The reason for this is that as the Chain Reaction is carried on waste products or atomic I begin to collect in the few elements of the reactor. Since these fission products absorb some of the neutrons which feed the chain reaction they tend to poison the Chain Reaction and slow it down so that the reactor no longer operates at peak efficiency. If we think of this is being somewhat similar to the smothering of an ordinary coal fire by too large an accumulation of ashes we get a picture of what is going on. After a while when the sufficient amount of this waste material has collected in the fuel it must be taken out of the reactor and chemically processed to

remove the waste material. Then it can be returned to the reactor for there is still a great deal of unde consumed view that should not be thrown away. The difficulty and expense arises from the fact that this chemical processing is difficult to do. For one thing the fuel is highly radioactive and cannot be handled directly. Then too in most reactors built to date the few is in the form of precision machine few elements and these must be dissolved. The uranium recovered from the solution and then re fabricated. But if the fuel in the reactor could be used in a liquid state this expensive and time consuming re fabrication step could be saved. And the continuous circulation of liquid fuels might be a very good means of cutting the excess expenses involved. Because of this Oakridge has been pursuing the homogeneous reactor

experiment. Dr. Weinberg Could you tell us something more of the homogeneous reactor experiment that was carried out here at Oak Ridge. Yes certainly construction of the homogeneous reactor experiment at the Oak Ridge National Laboratory began in March 1951. After two years of development and design on the part of Oak Ridge scientists. It was built to investigate the chemical feasibility of maintaining a nuclear chain reaction with a liquid fuel at temperatures and pressures sufficiently high for the production of electricity from the heat that was released the reactor was completed and testing began. Toward the end of 1951. And the first nuclear chain reaction was achieved on April 15 1952 testing an experimental operation of the reactor at very low power continued as scientists and engineers perform numerous experiments to learn the characteristics and performance of the reactor and

by the end of the air it had been demonstrated that the reactor operated quite satisfactorily at low power. So the next experiments were carried out at higher power levels. On February 24 1953 the reactor was brought up to its full design power of 1000 kilowatts heat output. And the reactor steam was turned into the turban generator to produce about 150 kilowatts of electricity. After its very thorough 11 months testing period the homogeneous reactor went up to full power very smoothly with no unusual developments. Its performance was on the whole so uneventful that it seemed routine to the reactor operators. The reactor produced twice as much electricity as required to meet its own needs. All outside electric power to the building was shut off and the building and reactor operated with electricity from nuclear energy. The excess power above reactor in building demands was that into the laboratory electrical

system. Now I would like to talk to Mr. S. S. Bell who directed the actual construction and experimental testing. Mr. Bell would you first of all describe the reactor for us. The core of the homogeneous reactor experiment was a stainless steel spear only 18 inches in diameter. The liquid fuel was made up of enriched your own oil sulfate dissolved in water it circulated through this there at a rate of one hundred gallons a minute. When I say it was in rich down mean that about 90 percent of the uranium in the fuel was made up of the fissionable isotope of uranium known as U-235. When the reactor operated at its maximum power level of one thousand kilowatts the fuel solution left the core vassal at four hundred and eighty two degrees Fahrenheit and was cool to four hundred ten degrees as its heat was transferred to

water in a heat exchanger. Thus generating the steam which went to the turban. The fuel then returned to the coort to be reheated. When the reactor was operating the fuel solvent that is the water decomposed into hydrogen and oxygen when it was exposed to the continuous radiation present these gases had to be drawn off and recombined safely for this we used a flame recombining which may be described as an oversized Bunsen burner enclosed in a water jacketed cylinder. The water recovered in this fashion was returned to the fuel storage tanks or to holding tanks in this way. It was possible to vary the concentration of the fuel circulating through the reactor. This feature of variable concentration was used to control the chain reaction and the operating temperature. For example the reactor was

started by increasing the concentration of the uranium salt in the fuel solution and was shut down by dilution with water from the holding tanks. This eliminates the need for control rods. As a matter of fact this simplicity of design is the most remarkable aspect of homogeneous reactors. Thank you very much Mr Bell. Now let's talk to Dr. J.S. Ward hout deputy director of Oak Ridge National Laboratory and formerly director of the homogeneous reactor expect not to sort out what was learned as a result of the experiment. Several uncertainties were resolved regarding the nuclear and chemical behavior of aqueous form of genius reactors at the high temperatures and pressures required for a for power generation for one thing. It was proved that there was a remarkable degree of nuclear stability inherent in home in the homogeneous reactor which made the reactor very safe to operate.

We were able to control the chain reaction and the temperature at which the reactor operated merrily by adjusting the fuel concentration as a fuel solution heats up it becomes less dense with the result that there is actually less fuel in the same space in the reactor. This prevented heart harmful power excursions from taking place and contributed to its inherent safety. These of course are very important considerations. Furthermore this inherent ability of the reactor to control itself. And the flexibility allowed by changes in the fuel concentration eliminated the need for mechanical control and greatly simplified the mechanical design of the reactor vessel itself. Basically what was needed was a tank containing only those parts necessary to achieve the desired flow and distribution of fuel in the reactor. The heat was removed from the fuel by means of equipment external to the reactor

and since the secondary coolant at no time and as the reactor itself we were able to design this section for maximum performance without worrying about neutron absorption and other factors that have to be taking into consideration when the heat is removed from the reactor core. Well all these good points in a homogeneous reactor sound rather impressive at least to a layman like myself. Are there any apparent disadvantages to this design. Yes there are. Every reactor concept has its good points and bad points and the homogeneous reactor is no exception. There are several disadvantages to homogeneous reactors. The first results from the fact that the liquid fuel which is extraordinarily radioactive must be circulated at high temperature and therefore high pressure throughout the reactor in order to produce electricity efficiently.

The entire circulating system must be absolutely tight so that these highly radioactive substances do not escape all the pomps piping and heat exchangers through which the liquid fuel flows become radioactive so that the replacement or repair must be done by remote control. This can be very difficult and expensive. Can we overcome this disadvantage by building reactors that are leak proof and which will not require repair of difficult to get at places. There seem to be good indications that we can. We know we can make the system absolutely leak tight from the experience gained from the homogeneous reactor experiment which circulated the equivalent of a ton of radium under high pressure and never had a high pressure leak during its period of operation. Like you said there were several disadvantages What was the second one. As we said a while ago the liquid fuel is a chemical compound called Yarnell

sulfate. Unfortunately your high temperatures readily attacks many metals that would normally be used for pipes pumps and heat exchangers. This poses corrosion and erosion problems. The only statement that can be made at this point is that in the homogeneous reactor experiment the fuel in the stainless steel core vessel were sufficiently rugged to withstand a protracted test period. Well thank you very much Doctor sort out. The homogeneous reactor experiment was dismantled in 1954 after two years of successful operation. But by that time it had demonstrated the fact that this type of reactor was a good gamble to take in the attempt to find the most practical safe and economic methods to produce atomic power. Today a larger version of this type of reactor is being built at the Oak Ridge National Laboratory as a part of the five year power reactor development program of the Atomic Energy Commission.

I'm now standing on the side of the somewhat unius reactor 10 in a moment we'll talk to one of the men responsible for its design and construction. Before we knew that. Let me describe it for you it looks today as if there is the final road to complete. A homogeneous reactor site is what made it about 12 miles from the center of downtown old bridge and by the way out of sight of the other side of one of the long cold top ridges. That surround the city on two star sidelines at the end of a White Russian on the road that makes up a low hill to a high rectangular shaped aluminum chat about how they react. The building itself is barely functional into. The center portion of the structure which houses the homogeneous reactor is 90 feet long 35 feet wide and 40 feet high. On each given by the low

structure a 20 feet wide housing for Cohen equipment room and office space. The reactor itself lives in a chair in the back. Of the building. Twenty five feet deep and could hold water it will be. But the other day on the water repairs the reactor pumps and equipment are radioactive and you cannot get the sun went directly and all the water becomes transparent long metal rod with tools on there and will be employed to remove one out of weapons and make repair. The hole might crumble of weapons down the construction at the near the final days of complete sand on a wooden platform extending out over the reactor plant. I can look down beneath me and watch two man artists work in very tight quarters among the valves and by being in the pit the pressure about the of the reactor is surrounded by pipes varying side and fanning out in all directions from it very cold

but it but instead of my going on why don't we have someone who really can describe it do it in a competent fashion you've already met him Mr. as well. In the very center of the reactor Assembly it is the core. It is a 32 inch diameter pear shaped vessel of zirconium alloy and it holds the liquid fuel of the reactor. The area around it is called a blanket region in which new fissionable material can be produced by breeding if desired or if the reactor is not to be used as a breeder this area can be filled with heavy water to act as a reflector to keep the neutrons where they belong in the core of the reactor. This blanket pressure vessel which we think would withstand the pressure of 18000 pounds per square inch before bursting has been fabricated from to hima spheres of four inch steel clad with a four tenths inch layer of stainless steel.

This pressure vessel has been enclosed in a 1 and a half inch thick stainless steel sphere spaced three inches from the heavy a vessel to protect other equipment in case of an accident. This entire assembly is located inside the reactor shield time which is down in the shield pit in the center of the building. The reactor shield tank is made of three quarter inch welded steel plate that has been reinforced so that it can contain a pressure of 30 pounds per square inch. It is 54 feet long 30 and 1 1/2 feet wide and it extends 25 feet below ground level. By itself it looks something like an indoor swimming pool. Its size is an interesting contrast to the size of the reactor core which is we said was only thirty two inches and diameter. But its there to protect personnel and equipment from contamination by radioactive materials. And it also holds the storage

tanks for the heavy water moderator pumps and piping that leads to the heat exchanger. All of which are radioactive because of the hot. Liquid fuel which circulates through them. This shield tank and all equipment in it have been designed and placed down in this pit so that the shield pit can be flooded with water to provide a flexible shield which protects workers during maintenance operations. A special long handled tools will enable them to make repairs while standing at ground level. Much of the maintenance procedures will take place on the water. Since water acts as a radiation shield in order to decrease the amount of neutron activation of equipment inside the shield tank the reactor vessel is dissed is surrounded by a shield for thermal neutrons consisting of one to two feet of a mixture

of bright tea sand Coleman night and water contained in a steel tank in the shape of an igloo. The upper surface of the Rue shields slabs will be at ground level so that the reactor itself will be underground. The roof is to be constructed of high density concrete five feet in total thickness. It will consist of two layers of removable slabs with a completely welded steel sheet sandwiched between the concrete layers and extending across the top of the pit to form a gas tight lid. There is a wall between the reactor pit and the control room a area to protect the workers. This wall is constructed of two one half inch steel plates spaced five and one half feet apart. With the end of the meeting space filled with a shielding material such as high density gravel and water.

Once the equipment is installed and check for proper operation the tank will be welded closed and then not open until it is necessary to perform maintenance operations. How much power will a charity produce when it's finished. Well first of all in answer that question I think we should mention that HRT is the first of two homogeneous reactors to be built under the five year program. It will be a fairly modest version generating only five thousand kilowatts of heat. Its main purpose will be to explore a number of engineering problems. The age of our tea will be followed by a larger reactor with the heat output of at least 65 thousand kilowatts. This larger reactor will be used to breed new atomic fuel as well as to produce electric power. Well of the many problems we talked about that will have to be surmounted if this particular reactor design is to become a successful prototype for future power reactors.

Which one would you say is the most serious one to overcome. The problem of reliability of operation is common to all nuclear power reactors. In the case of the homogeneous reactors it includes reliability of mechanical components. Resistance of materials to corrosion by the liquid fuel in the maintenance of the system. Thank you Mr Bell. A commercial park planned to be economically feasible must not only cost a reasonable figure to build but must also operated very high temperature levels for very long periods of time without costly repairs shutdowns or replacements. And it must convert large quantities of heat efficiently into usable power. One thing that's worth remembering about these systems is that when they are built they're built once and for all there is no climbing in and out of the ducts and pipes to fix leaks and brakes. Unless you're willing to risk a lethal dose of radioactivity but these problems are being solved and a good share of the design development and research work that is taking place today at such

places as the Oak Ridge National Laboratory will speed these solutions. This week's program of atoms for power was transcribed at open Ridge National Laboratory and Oakridge Tennessee next week. Atoms for power will take you to the nation's first full scale atomic power reactor at shipping port Pa. For more information on atomic power for our nation. I don't use for power was written and produced by Bob McMahon for a radio station WABE at Purdue University under a grant from the education over television and radio center scientific advisor the program was Professor Donald J tandem of the Purdue Department of Physics or narrators where Walt Rector and Jim Holston. And this is Jack Carroll's because this program is distributed by the National Association of educational broadcasters This is the

B Radio Network.