ATOMS FOR PEACE

[Music] [Music] peace and moscow the two words are associated in the minds of progressive people everywhere from moscow came the good news in 1954 that the first atomic power plant in the world had begun operating in the soviet union its creation was not only a great scientific achievement but also a new triumph for the great ideas of peace and friendship between the nations the peaceful applications of atomic energy are many and buried in the soviet union [Music] the energy latent in the atomic nucleus is released in special devices called atomic piles or reactors [Music] this is a reactor for research purposes what happens inside the reactor if we remove the protective lid we can peep inside the reactor while it is operating at a low power output see the bluish glow this glow is due to the effect of the radiation on the water filling the reactor tank if we were to descend underwater we would see something like a lattice of rods on the bottom of the tank the rods in special holders are of metallic uranium each rod is in an aluminium jacket here is a simplified picture of what atoms of uranium are like electron shells surround the atomic nuclei [Music] now let's have a better look at the nucleus of the uranium atom it consists of positively charged particles called protons designated red and uncharted particles called neutrons designated yellow nuclear forces hold the particles together if a free neutron approaches the uranium nucleus these forces will draw it into the nucleus which will undergo excitation and then disintegrate let us check this process here are two splinters of the nucleus and here are the neutrons released in the course of this disintegration the breakup of the nucleus initiates the evolution of nuclear energy the greater part of this energy is carried by the sphincters they scatter in different directions at tremendous velocities transferring the energy to other uranium atoms as a result of this the temperature of the uranium rises atomic energy is converted into heat this process of nuclear fission gives rise to a radiation which is dispersed in the surrounding media but what happens to the nutrients from the rod they pass into the water here is a view of a uranium rod from above on hitting the particles of water the nutrients are slowed down slowed down however the nutrients are easily absorbed by the uranium nuclei in the rocks these nuclei in turn break up emitting new free nutrients a chain process of nuclear fission is thus initiated and a rapid buildup of heat takes place if this process is allowed to get out of hand the reactor will be destroyed to keep the fission process under control there are rods made of a good neutron absorber by shifting such a rod it is possible to maintain a desirable rate of the process or stop it all together here is a cross section of the reactor the reactor is surrounded by a thick wall of concrete water or iron to protect the personnel from the radiation for a thermal column nutrient be obtained for research purposes [Music] the water circulating through the reactor tank serves to reduce the nutrient speeds it also serves for heat nation the heat may be used for industrial purposes for example in the reactor of an atomic power plant it is used to obtain [Music] turbo generators then transform the energy of the steam into electric energy atomic reactors can be used not only for obtaining energy but also for the nutrient bombardment of various materials here is one of such reactors [Music] it has special exposure holes for such bombardment [Music] the reactor is being loaded a tube containing samples of the material to be bombarded is lowered into the exposure hole [Music] when the preparations for the bombardment are complete [Music] the reactor is operated from a switchboard in another room what happens to the irradiated material the nutrient beam penetrates the walls of the tube and bombards the samples this nutrient bombardment alters the composition of the nuclei of the material the newly formed nuclei are unstable and therefore emitter radiation the substance becomes radioactive that is how radioactive isotopes are formed artificially what kind of a radiation do they emit if we subject this radiation to the action of a magnetic field we get three distinct beams of rays [Music] on the left is the alpha radiation consisting of positively charged particles which are helium nuclei these particles have a velocity of twenty thousand kilometers a second but a mere sheet of paper is enough to stop them on the right is the beta radiation consisting of negatively charged electrons their velocity can reach 250 000 kilometers a second the beta radiation passes through paper but it can easily be stopped by glass these are the gamma rays a hard electromagnetic radiation like radio waves it moves for the speed of light gamma rays easily pass through paper and glass a thin slab of concrete checks them only partially thicker slabs absorb them almost completely [Music] the high penetration of gamma rays is a danger to men that's why the removal of the tube of with the samples of radioactive materials is carried out by remote control from another room [Music] the operator performing this is able to watch the whole process this enables him to carry out the operation with a necessary precision he transports the tube across the hall to a special manhole in the floor the tube is in this way lower to premises where the irradiated samples are removed from it work with radioactive isotopes requires special conditions to protect people from harmful radiations the isotopes are stored and transported in massive containers but even in these conditions it is necessary to check with the aid of a special instrument whether there aren't any radioactive substances on the surface of the container now the container with the isotopes is taken to the so-called hot laboratory the reason it is called hot is that it deals with highly radioactive substances the techniques employed in the steel chambers of this laboratory ensure complete safety for the personnel [Music] the heavy protective door of reinforced concrete is hermetically sealed and no one may now enter the chamber but who does the job in that case this again is done by remote control from the neighboring room by means of special mechanisms called manipulators manipulators are mechanical hands that reproduce every movement of the operator's hands the operator watches the work through a lead glass window through which the radiation cannot pass [Music] let's see how the manipulator works the operator has to get the tube out of the container and extract the radioactive samples from it [Music] now the empty tube has to be put back into the container [Music] these tongues are inconvenient for subsequent operations however there is a wide range to choose from [Music] everything is ready and one of the samples can now be treated the rest had been better put aside for the time to be out of the way so [Music] the remaining sample must be cut this is not difficult to do the necessary tools are always close at hand the sample is gripped in a vice now it is necessary to adjust the saw [Music] the cutting is done under water so that the radioactive dust should not mix with the air the sample is cut in this way by using manipulators it is possible to perform various operations and give the samples any shape the separators determines the strength of the radioactive samples for this it is necessary first to open the lid of the apparatus then a small sample of the material is put into it [Music] the lid is closed the apparatus has got ready and finally put into operation to open the lid again it is necessary to check the pendulum then the pieces of the sample are removed [Music] so [Music] there are different types of manipulators this kind of manipulator is used for the chemical study of radioactive substances [Music] this is a so-called screw manipulator [Music] the mechanisms of the manipulator are checked periodically first the premises have to be cleared of radioactive contamination a special suit protects the worker from radioactive dust a water shield provides additional protection [Music] isotopes emitting an alpha radiation or a weak beta radiation are handled in different conditions glass boxes with inserted rubber gloves are used for protection in this case there are quite a few devices in the hot laboratory to protect the health of the personnel no admittance the apparatus has detected traces of a radioactive substance on a workers suit the contaminated suit has to be discarded and a fresh one put on [Music] the radioactive radiations of isotopes are used for diverse purposes their damaging effect on living cells can be made to serve men it finds application in many medical institutions the oncological research institute this apparatus is charged with radioactive cobalt it is called a cobalt gun this gun however doesn't kill people but restores their health this patient has a malignant tumor on his neck the gun is trained on it during the preparations the isotope is inside a thick walled sphere which its radiation cannot penetrate the preparations are now complete and the medical workers go to a neighboring room so as not to be under constant irradiation a device is switched on which automatically regulates the radiation dose the isotope moves up to the working chamber the radiation has begun the gamma rays damage the tumor cells and thereby check the further growth of the tumor [Music] there is a communication line to enable the doctor to inquire how the patient feels as soon as the radiation time expires the apparatus is automatically switched off and the isotope moves back into the container [Music] [Music] tubes of different size and shape are used for irradiation depending on the size of the tumor and its location when the tumor is a deep seating one the patient is treated in a revolving chair the chair is fixed so that the ray should reach the tumor all the time the fact that the chair evolves reduces the time that healthy tissues are subjected to irradiation here's another apparatus for irradiation it contains less radioactive substance and produces a narrower beam of rays what are the results of the treatment unfortunately it does not always produce complete recovery but in many cases its effect is amazing here's a picture of a patient who had a malignant tumor of the lower lip here here's after the treatment there is no trace of the tumor this was achieved without recourse to surgery by irradiation alone here's another case this patient had cancer of the mammary gland the doctor advised radioactive irradiation cancer of the mammary gland is treated by introducing needles of radioactive cobalt into the gland the needles are kept in a container [Music] they are prepared for the operation on a table fitted with a protective shield [Music] when ready the needles are placed in a safe through which the radiation cannot penetrate [Music] the operation [Music] the doctor attacks the tumorous cells by introducing needles into the tumor the radioactive radiation damages the tissue surrounding the needles and in this way checks the growth of the tumor cells the healthy tissues are thus practically not subjected to irradiation at all [Music] an x-ray shows the position of the needles [Music] tests after the treatment revealed that the tumor had disappeared complete recovery says the doctor what a message of happiness there is in these words radioactive isotopes can also be used for the treatment of other diseases this mother has brought a daughter to the doctor what is the trouble with her [Music] the doctor has to urge the girl to turn angioma the congenital disease of the skin is flavoring the face which until recently was considered incurable now this too is cured by radioactive isotopes in preparation for the treatment the afflicted area of the skin is carefully measured an applicator or mold of the required shape is then made [Music] [Music] it is into this applicator that pieces of radioactive cobalt are placed [Music] the applicator is ready it's applied to the afflicted area of the skin and fastened with bandage [Music] the process of irradiation has begun arrays penetrate into the tumor and destroy it each session lasts from two to four hours the entire treatment takes about a fortnight the children usually play games for getting all about the treatment which is quite painless several months have passed and the girl is bought to see the doctor once again [Music] look this way marina dear now you're quite well when you grow up you will be very thankful to those who at the very dawn of the atomic age cured you with these magic rays radioactive radiation can be used successfully to alter the physical and chemical properties of many substances these are articles made of polyethylene available plastic used in the electrical chemical and other industries but polyethylene cannot stand high temperatures a cork placed into hot glycerin becomes soft and shapeless [Music] let's see what happens if we treat the polyethylene with radioactive cobalt [Music] a special apparatus is used for sachi radiation the lab worker places the polyethylene articles inside an exposure chamber the radioactive isotope is still in its container here is a cross-section of the container a special cork keeps the isotope and the radiation inside now the exposure chamber is loaded all subsequent operations are remote controlled the door to the chamber is locked the cork of the container rises now the container moves [Music] it comes to a stop underneath the exposure chamber the rod with the isotope comes up and the isotope is inside the chamber the irradiation of the articles in the chamber now begins [Music] as a result they acquire new properties the polyethylene can now stand much higher temperatures it no longer melts into a shapeless mess the use of radioactive isotopes thus opens up new prospects in the field of obtaining plastics with valuable physical and chemical properties radioactive substances find application in diverse branches of industry they have been successfully applied for instance to oil prospecting the station conducting the prospecting is mounted on motor vehicles inside it has apparatus for the automatic reading of the data obtained the cable stretches from the station connecting it with a special shell inside the shell which is shaped like a long cylinder not counters registering radiation the prospecting is done with a mixture containing radioactive substances and emitting neutrons the shell is ready to be lured into a borehole [Music] after being lowered to a definite depth the shell is lifted to the surface it is now for the actual investigation begins the neutron emitter sends out a flux of neutrons in all directions they penetrate into the rocks around the borehole let's trace one beam of neutrons when the neutrons enter the rock it becomes radioactive and the radiation arising in it is registered by the counters the nature of the radiations can be observed on the screen of an oscillograph the natural radioactive radiations of the rock are registered by other counters [Music] with the movement of the shell and the change in the type of rocks there is a change in the radiation the picture on the oscillograph changes accordingly [Music] photographic curls are obtained as a result of the prospecting by which geologists are able to determine what type of matter surrounds the borehole sandstone clay [Music] the penetrating ability of gamma rays is put to use in many devices employed in industry here is one such device the gamma defector scope inside the box is a container with radioactive cobalt with the aid of this device it is possible to detect hidden defects in metal castings and forgings in this factory lab preparations are underway for such tests the exposure chamber is placed underneath the detail to be tested underneath it is placed an adapter with a photographic film the apparatus is operated from the next room by pressing a button a special mechanism is made to shift the isotope from the container along a tube to the exposure chamber now the flux of invisible gamma rays passes through the plot and reaches the film exposing it after irradiation the isotope is sent back to the container [Music] [Music] the film on being developed reveals all the defects of the casting there's a tiny crack hidden to the naked eye these are concealed cavities in the metal gamma defector scopes are simple and convenient to use they require no electric current and can therefore be used anywhere gamma defectoscopy is a much faster and cheaper method of examining metal the method is a particular asset in shipbuilding electric welding is widely used in building ships the quality of the welded seams must be carefully checked [Music] this can be done with the help of light portable defector scopes with radioactive cobalt the defector scope is placed on one side of the ship's hull while a magnetic adapter with film is applied to the seam on the other side the defector scope is trained on the section to be tested when an aperture is opened a beam of rays issued from it penetrating the seam and exposing the film the test is over the film has registered all the defects of the welded scene radioactive isotopes make it possible to test themes quickly and reliably [Music] this is a hydraulic dredge at work with the help of a special device it sucks up a mixture of earth and water and sends it along pipes to building sites several miles away a dam is being built here if the mixture does not contain enough earth the work proceeds slowly if on the other hand if there is too much earth it can clog up the pipes it is very hard to determine the density of the mixture and this used to be done very approximately [Music] now this is done with a high degree of accuracy by a special device inside the hood under the pipe is radioactive cobalt its radiation goes through the moving mixture to a counter connected with an indicator with every change in the density of the mixture there is a change in the amount of radiation reaching the counter and the indicator shows the change [Music] it is now easy to maintain the required density of the mixture [Music] the device points to any departure from normal density steps can be taken at once to bring the density back to normal the use of these devices increases the efficiency of hydraulic dredges by about 20 percent [Music] many other devices determining density thickness and weight operate on the same principle a textile mill this is where thread is made from cotton yarn the yarn must be fed says to be of the same weight along its entire length only then will the thread be of uniform thickness but determining the weight of the yarn is a very long and painstaking job first it is necessary to take many samples of the yarn each sample then has to be carefully weighed [Music] the results have to be tabulated [Music] then there are complicated calculations to be made all this takes up much time a radioactive isotope device does the job much more quickly and accurately this little container has radioactive gallium inside there it is [Music] the radiation of the isotope passes through the moving yarn and is registered by a counter the counter is connected with a recorder [Music] let's try to reduce the weight the recorder at once registers a sharp departure from normal weight now let's increase the weight the curve sweeps in the opposite direction the device saves much time [Music] of course it isn't absolutely necessary to use isotopes to counter bottles coming off a conveyor this can be done by many other means but if necessary a radioactive counter can do this job as well [Music] the ray runs from the aperture to a counter sensitive to radioactivity whenever anything pulses the aperture it intercepts the ray this moment is recorded by the counter [Music] the radioactive counter never makes a mistake [Music] radioactive isotopes can be used not only as sources of penetrating radiation but also as tracers the radiation is here a tank which makes it possible to trace an isotope and detect it wherever it may be an example will serve to explain this scientists studying the movements of fish sometimes label fish [Music] the labels make it possible to trace the seasonal movements of the fish and establish their spawning places [Music] but how can these tiny things be labeled the ordinary labels are useless in this case radio isotopes furnish a solution to the problem a small quantity of radioactive phosphorus is added to the water where the fish are in a couple of hours it can already be detected in the bones fins and scales of the fish if let loose into the sea the fish will need a normal life and develop the amount of radioactive phosphorus in their organisms is so small that it cannot harm either the fish or human beings but it can always be detected all that's necessary is to subject the fish court at choice to a laboratory test [Music] sensitive instruments detect the smallest doses of radioactivity this makes it possible to detect labeled fish and obtain data