remedy this deficiency, I will, in the second part of my address, make use of a film which has a German script. Its history of the development of nuclear power, of course, goes back a

long way, 60 years in time, and its development has depended on the work of the great pioneers, Rutherford and Bohr, Chadwick, who discovered the neutron, and Hahn, who

discovered the fission of uranium, which for the first time opened the feed to nuclear power. And finally, Fermi, who at the end of 1942 achieved the first controlled chain reaction in his atomic pile in Chicago. In the years after the first nuclear reactor of Fermi, they

were the warriors, we did not begin to think seriously about nuclear power until around about 1948. During that period, from 1946 onward, I was director of the Harwell Atomic

Energy Establishment, and we began to think seriously about the possibility of nuclear power. You may ask, perhaps, why should we worry about nuclear power, when today we have a

surplus of oil, so we are told, and coal. On the other hand, if you look to the end of the century, by which time the world's population will have doubled, and our standards of living will have increased, there seems to be no doubt that nuclear power will be essential. In our country, in Britain, the requirement for nuclear power comes much earlier.

At present, we use 60 million tons of coal a year for producing electricity. By 1980, we will be requiring 170 million tons of coal, or its equivalent. And since we have a coal production of only about 200 million tons of coal a year,

it seems to us to be essential to add a further source of energy to our economy. One of our first problems in Harwell was to decide on the type of reactor we would use

to develop the heat required for nuclear power stations. May I have the first slide, please? We chose, this is a typical reactor, a so-called thermal reactor, in which the neutrons from fission are slowed down by,

in this case, a graphite moderator, to the energies at which they are specially effective in producing fission in the light isotope of uranium, uranium-235. So this type of reactor, the so-called thermal reactor, essentially makes use mainly of the energy,

fission energy of U-235. On the other hand, some plutonium is produced as the neutrons are slowed down by capture in uranium-238. And this plutonium, in turn, can be fissioned. The heat from this reactor is usually transferred by one type of fluid or another,

in this case, carbon dioxide gas, to heat exchangers where steam is raised. The next slide, please. This slide shows a perfectly conventional power station at Calder Hall, which is used for generating the electricity. Next slide, please. The other type of reactor we did consider at that time was the fast reactor.

The fast reactor is characterized by making use of fission before the neutrons from fission are appreciably slowed down. It has a very compact core of fairly pure fissile material, either uranium-235 or plutonium. And the surface neutrons are captured

in uranium-238, either outside the core or inside or on top. And the characteristic of the fast reactor is that you can produce more fissile material, breed more fissile material than you consume.

However, at that time, towards the end of the 1940s, it seemed to us we would not have enough fuel, plutonium fuel, to produce fast reactor power stations. You require something of the order of one ton of plutonium

for high power station using fast reactors. We had, therefore, to make a choice between the different types of thermal reactors. You can have a thermal reactor in which the moderator is ordinary water or heavy water or beryllium or graphite.

You can remove the heat in various ways by ordinary water, by heavy water, by gas such as helium or carbon dioxide. The United States have mainly followed the route using heavy water as a moderator, using heavy water to carry away, using ordinary water to carry away the heat.

These like-water moderated reactors require enriched uranium. We chose reactors using a graphite moderator, in which we use carbon dioxide as a heat transfer gas, because in this case, we could use uranium, natural uranium.

We would not have to use enriched uranium. And furthermore, we were able to manufacture graphite, pure graphite, with the industrial facilities we already had. Now, I will speak briefly about some of the technological problems which had to be solved. The next slide, please.

One of the first problems was to find a way of making uranium metal, which would not distort badly under the influence of neutron bombardment inside the reactor. This slide shows how uranium can distort under neutron bombardment if it is not properly prepared.

This is because uranium is made up of a multitude of crystals, and the single crystals will grow in one direction and contract in another direction. So it is possible to get very severe distortion. This growth is due to the production of dislocations in the uranium metal,

which are preferentially orientated. The remedy for this is to produce uranium metal, which has a multitude of very small crystals, and in which the orientation of the crystal is random. And this can be done by heat treatment,

by first of all heating the uranium to the higher temperature phase, called the beta phase, and then quenching it under controlled conditions. You can then produce uranium which does not distort appreciably under neutron bombardment during a period of two or three years when it is in the reactor.

The next slide, please. The second problem is to find a material to sheath the uranium to prevent the radioactive products of fission leaking out. If they leak out, they will contaminate the reactor, and you will have a heavy maintenance problem on your hands.

It is necessary to choose a material for the sheathing of the uranium, which has a low absorption for neutrons for fairly obvious reasons. And we chose an alloy of magnesium, which has about 0.8% of aluminium and 0.01% of beryllium.

It is also important that the sheath should have a reasonably high melting point. This alloy melts at 650 degrees centigrade. This means that we can operate the surface of the fuel elements at temperatures up to 450 degrees centigrade.

We have to allow a substantial margin because in operation you may possibly have an overshoot of the temperature and it would be somewhat unfortunate if you melted the fuel element sheet. Another very important factor in these sheaths is that they should have a very high degree of integrity.

At one end you have a well to close the sheath, and it is extremely important that there should be no leaks in this well. Otherwise, you get an in-leakage of the hot carbon dioxide gas, which will creep in and oxidize the uranium metal. A mound will fall, and it will push out the sheath,

and this will lead to a break. As a result of the development work carried out over quite a number of years, we now find that we can produce fuel elements of this kind in which, out of 10,000 fuel elements in a reactor,

we only get about 10 faults, 10 leaky fuel elements per year. That is about one in a thousand, and that is the satisfactory level at which to aim. Another important technological problem we had to study was the chemical problem,

the compatibility of hot carbon dioxide gas with graphite, since this can lead to the production of carbon monoxide. It turns out that although this chemical reaction is increased 10,000 times by radiation, that the level of carbon monoxide only rises to about a half percent.

The worry here is that you may possibly get some transfer of graphite from one part of the reactor system to another. However, this has not turned out to be troublesome. Another important problem is the so-called Wigner energy storage in graphite.

When neutrons hit the carbon atoms, they displace a number of them into positions between the planes of the graphite, and energy is stored. You can store energy in graphite up to a level of over 200 calories per gram,

and if you heat up graphite with a very large amount of stored energy, then you may get spontaneous rises of temperature, which can be somewhat unpleasant. The remedy for this is to keep the graphite at a temperature of over about 220 degrees centigrade

when it is being irradiated in the reactor, and so therefore we do not now find this problem is a serious one. Another problem is to so design the surface of the sheath of the uranium metal that you get a good transfer of heat from the surface to the hot gas,

and there has been a progressive increase in the efficiency of the heat transfer in this kind of reactor. Now about the Calder Hall nuclear power station. This came into operation in 1956.

Next slide please. This is the typical fuel element that we now have in the Calder Hall reactors. Next slide please. This slide shows the Calder Hall nuclear power station. It now has four reactors and two power stations, one here and one here,

and produces about 150 megawatts of electricity and produces 1,000 million units of electricity a year. It has been joined by a twin station, next slide please,

at Chapel Cross just across the border in Scotland, which produces another 1,000 million units of electricity. These power stations have given extremely little trouble. In the early years we had a few minor teething troubles, which were mainly troubles with mechanical equipment,

which you nearly always get, and also trouble with standard electrical equipment, such as motors driving the circulating fans for the carbon dioxide gas. But on the whole they have performed extremely well. One of the important points about the behavior of a nuclear power station

is the amount of heat which you can extract from each ton of uranium metal. There are two limits to this. The first limit is that you must always have a surplus of neutrons in the chain reaction, and during the course of the chain reactions your neutron surplus at first falls slightly

due to the production of a samarium fission product. Then it rises as plutonium is produced, and then it falls again. In the reactors of this Calder Hall Chapel Cross type, we would be limited to extraction by a neutron surplus

to extracting from each ton of uranium the heat equivalent of about 15,000 tons of coal. Another way of putting that is that we should extract from each ton the equivalent of 4,500 megawatt days of heat.

We thought at first that we might be limited by the radiation damage of the fuel elements to extracting heat corresponding to 3,000 megawatt days per ton. And so our experience in Calder Hall has been extremely important.

We have found already that many fuel elements have exceeded this target of 3,000 megawatt days per ton, and some have gone to a limit of 4,500 megawatt days per ton and still are going quite well. And so therefore we feel sure now from this experience

that we can achieve low fuel costs in these power stations, fuel costs of the order of one-half of the fuel costs in coal-fired stations. And that of course is essential because capital costs of nuclear power stations are present considerably higher than capital costs of coal-fired stations.

The next important question was the dynamic behavior of the reactor. The next slide, please. This slide shows how the power level changes in the reactor. It looks as though it is rather fierce excursions here, but if you look at the scale on the right-hand side,

you see that these excursions of the power level are really quite small of the order of one percent over a long period of time. We find also that the operator may take his hands off the control rods and leave the reactor to run itself.

If he does that, there will be a drift in the power level of only about one percent in a time of 20 minutes or so. And so therefore we have found these reactors to be very docile and easy to control. The next slide, please. During their life, as a result of improvements in the operation,

we have found it possible to increase the heat extracted from one reactor in the course of time quite substantially of the order of 25 percent. And so therefore this has been a very satisfactory performance. Another important question is the time during which the reactors can stay on full power.

These reactors, and Calder Hall and Chapel Cross, have their fuel changed about once a year. We find that in the intervals between changing the fuel, they can operate on full load for 95 percent of the maximum possible time.

And so therefore, again, it seems possible that the reactors in the future can operate with so-called very high load factors. The next stage of the British power program

is to construct eight commercial nuclear power stations for our electricity generating board. The first of these power stations, which has an output of about 300,000 kilowatts, is situated on the Severn at Barclay near the old castle

and has just come into operation. The successive power stations will rise in power levels to something of the order of 550,000 kilowatts by 1968, and we will then have a total capacity of 3,500 megawatts.

Beyond that, again, the output of this type of nuclear power stations is forecast to rise to 800,000 kilowatts or even to a million kilowatts. The next slide, please. The reason why we have been able to steadily increase the output from the reactors

is first of all that we have changed to larger reactors, which contain more graphite and more uranium. Second, we have increased the amount of heat which can be transferred from each ton of uranium to the hot gas by improving the heat transfer characteristics by increasing the gas pressure

and also by increasing the temperature of the uranium fuel elements. And in doing so, the efficiency of conversion of heat to electricity has been improved by 50%. The next slide, please.

This slide shows the station at Barclay on the Severn which has just come into operation and which will be generating 300,000 kilowatts. The next slide, please. This slide shows the progressive increase in the temperature of the gas

leaving the reactor from different models. Our early reactors had quite a low gas outlet temperature, 200 degrees centigrade. Colder Hall, about 300. And then with the successive power stations, the exit gas temperature growing up to something of the order of 350 degrees centigrade.

And this, of course, is good for the efficiency of conversion of heat to electricity. Now I'm going to say just a few words about the capital costs of the nuclear power stations. Next slide, please. This slide shows the capital cost per kilowatt of these nuclear power stations,

starting with the early ones, Barclay at the top. In considering these figures, you have to remember certain conventions that for one reason or another, for interest charges during construction, for site charges, you have to add about 25 percent to the cost as quoted by a manufacturer of the nuclear power station.

And so you see that the costs here have steadily decreased over a quite short period of time from 168 pounds a kilowatt down to 110 in the stations which will come into operation round about 1968.

And there is every reason to believe that the cost of this type could be still further reduced with increasing output. Now about the cost per unit of electricity, there are certain conventions about this. First, it depends on the interest rates which you must pay.

We allow 6 percent. There is a convention that a nuclear power station will have a life of 20 years. We have examined the Calder Hall reactors by television cameras. We find no evidence whatever of deterioration and see no reason why the life should not be longer, 25 or 30 years.

There is a convention that these power stations will operate for 75 percent of the time. We know now they could operate for a much larger proportion. Uranium costs were initially assumed to be 8 dollars a pound of uranium ore.

We know this will come down fairly rapidly in the future. And so on. In comparing nuclear power costs with conventional power costs, we take the best and largest coal-fired station which has so far been thought of in England, a coal-fired station to develop 2 million kilowatts

situated on the coal fields in the most favorable place, and we gather that such a power station by 1968 could generate power at 2.35 pf per unit. If we take the latest of these stations, Sizewell station, then we find that on the pessimistic assumptions,

this power station could generate electricity at 3.1 pf per unit. With the more optimistic assumptions, which we believe to be justified, this figure would be 2.5 pf per unit. And therefore we feel that by the end of the 1960s,

there would be very little difference in the cost of power from conventional stations and from nuclear stations. However, we are preparing to make a jump in our technology by the early 1970s, and we are developing a new kind of reactor

which again uses graphite as a moderator and carbon dioxide as a heat transfer medium. We are calling this the advanced gas-cooled reactor. The objective here is to increase the gas outlet temperature from our earlier level of something like 350 degrees centigrade

to something like 550 degrees centigrade. This would allow the efficiency of conversion of heat to electricity to be greatly increased to something of the order of 40%. In order to achieve this, the fuel element temperatures

will have to increase to over 600 degrees on the surface, and therefore we will change from uranium metal to uranium oxide, and the sheath will be changed to stainless steel, which in the first place will have a thickness of about 0.4 mm.

We believe that with this new kind of uranium oxide fuel, we should be able to extract six or seven times as much heat per ton of uranium as in the earlier types. And taking account of all these factors, the capital costs would be appreciably lower

than we believe that the cost of electricity from a nuclear power station in the early 1970s would be round about 2 FENEX per unit. Beyond that, again, the next slide, please, this slide just illustrates the progressive increase in efficiency

of the successive types of power stations going up to 40% in the case of the advanced gas-cooled reactor. We are also in collaboration with about 12 European nations seeking to reach still higher temperatures of operation in the so-called high-temperature reactor,

and the model of that is being built at Memphis Heath and will come into operation sometime towards the end of next year. This is a further step in the development of this particular technology. Finally, I would just like to say a few words about the fast reactor.

We are building at Dunray in the north of Scotland a fast reactor, an experimental fast reactor, which was designed to produce about 60 megawatts of heat. The reason why we are interested in fast reactors is because they offer the prospects of a much greater utilization of uranium.

If we think of the situation in the year 2000 when we might perhaps have to develop the heat corresponding to 6,000 million tons of coal for power development, if we could utilize 50% of the total energy efficient of uranium,

this would only require 4,000 tons of uranium a year. On the other hand, if we could only utilize 3% as in the best of the thermal reactors, then we would require 60,000 tons of uranium a year.

And so, therefore, we believe it to be very important to develop the technology of fast reactors. The film will show, first of all, the development of the thermal power stations, thermal reactor power stations. It will show something of the advanced gas-cooled reactor

and finally will show the details of construction of the fast reactor. So now I will ask the operator to show the film. That is a view of the fast reactor at Dunray in the north of Scotland. May I have the film please now?

There are 5,000 megawatts at the same time. The operation of the first and third workers was done in 1950. Here the electrical power station is now at 900 megawatts per train. A speed of 100 megawatts per train.

The operation of the next worker leads an acoustics facility in a bright and fluffy place.

The facility is in a building. In 1960, the power station began to work in Oldbury. The city of Goebb, a private construction company and industrial and manufacturing company, became the first-class engineers.

And now we have a lot of new people. These are the start phases for the reactor in Inglipoy, in Sussanbaar, in Fabrik,

where there is a shift of power station and there is a long-standing shift of power station.

This is the Arweg Forum. In many industries in the whole country, there are many programs like power and force.

Here we have a very large area. In the last 10 years, in the history of Brinstorf, the gas-cooled reactors have been built. The construction of the Brinstorf Element has been built from ground to ground. For the first time in a bar,

there is a building called Kapsunstraße. We are now in the city of Ganger. The first reactor in the year 1960 was built.

The first reactor was built by the Brinstorf Element in the reactor Eingebracht. It was a very big site in Germany. The first reactor was built by the Brinstorf Element and was built by the industrial and manufacturing company

of electricity.

The first reactor was built in 1950, with the foundation of the fundament of L-M. Before the Brinstorf Element, the reactor was built in 1950, while the magnet was built.

Here, the Brinstorf Element was built by the Brinstorf Element. It was built in the year 1960. When the drones were built in 1950,

the company of the Brinstorf Element was built in 1960. The first reactor was built in 1950, while the Brinstorf Element was built in 1950.

The construction of the Brinstorf Element was built in 1930. Here, the reactor was built in 1940. The first reactor was built in 1950,

while the building was built in 1960. A stardew was built in 1950,

while the construction of the Brinstorf Element was built in 1930. The building was built in 1950. The first reactor was built in 1950, with the foundation of the Brinstorf Element.

The construction of the Brinstorf Element was built in 1960. The design of the Brinstorf Element It was built in 1990, while the building was built in 1993.

It was built in 1940. The design of the Brinstorf Element

For us, the 26th day of the day in Stellung will be a very important event in the course of this graphic-moderating gas-cooling experiment. We are going to take a look at the magnets of the gas-cooling experiment, the light-compo-reactor of 600 megawatts in colder to 200 degrees Celsius,

as well as the gas temperature of the gas-cooling experiment. Here, the gas-cooling reactor will be a very important event. I'd like to introduce you to a friend of mine, Seiswel, in the old-style gas-cooling reactor.

The gas-cooling reactor will be a very important event in the course of this graphic-moderating gas-cooling experiment. The focus of the gas-cooling reactor, with the help of the 3d temperature of the gas-cooling reactor, is on the way to the Dragon Project in Winfreds, Germany. The help of this international experiment,

such as the electronation and ex-vitro in the White Army, is a 26-megawatt reactor, the new 60-kilometer reactor, with a temperature of 1200 to 1500 degrees Celsius. The reactor's physical state for this system

works with the help of the non-energy reactor Cenet, in which the temperature of the gas-cooling reactor is given to the circulation of the gas-cooling reactor. In the same way, in the Red, the Nöbingen-Schottland is a very important reactor system.

Here, the gas-cooling reactor will be a very important event in the course of this graphic-moderating gas-cooling experiment. The reactor will be a very important event in the course of this graphic-moderating gas-cooling experiment. The reactor will be a very important event in the course of this graphic-moderating gas-cooling experiment.

The reactor will be a very important event in the course of this graphic-moderating gas-cooling experiment. A lovely thing to note is that the radioactive material

is also used as a brand new gas-cooling reactor. The ant-wender and the metal anchor

of the air that is radioactive, and that is the most dangerous option for them.

The cool metals are used in the city. These pumps have no vehicles in the city, and therefore no engines in the city. The first one was used in the system, which was used in four or five parallel vehicles. The first one was used in the most dangerous vehicles, which was used in the most dangerous vehicles.

This is the first one, the central one. The first one is the coolest one, and this one is a worm, and this one is a secondary one. This is the first one, a metal flushing, which is not radioactive.

The flushing is used in the system, where the worms of flushing and nitrogen are used in the system.

The flushing is used in plutonium, which is used in the most dangerous vehicles. This is the first one, because plutonium is used in several reactors and platforms.

The flushing is used in the same way as 15 years ago. The flushing is used in the most dangerous vehicles, and the flushing is used in the most dangerous vehicles.