Part 6

The first atomic power plant in the world was built in the U.S.S.R. and went into service in 1954. There are now a number of such plants in the United States. Two of the largest are the Duquesne Light Company at Shippingport, Pennsylvania, near Pittsburgh, and Consolidated Edison's Indian Point Plant, in New York State.

Important as atomic power is to cities, it is of even greater importance to faraway places where fuel is hard to get. For example, at the U.S. Army's Camp Century in Greenland, far above the Arctic Circle, obtaining power had always been a problem. The cost of shipping coal or oil to such a place was so high that it was impractical. People had to get along with very little heat or power. But not any more.

Camp Century's new atomic power plant supplies heat and electricity for all. In a whole year the plant uses only 40 pounds of atomic fuel. If it ran on diesel fuel, it would need 850,000 gallons a year!

One of the strangest things about some atomic reactors (called breeder reactors), is that they make new fuel as they go along. If the fuel is uranium, it is usually a mixture of uranium-235 and uranium-238. Only the U-235 can be used for the chain reaction. But when the flying neutrons from the U-235 strike the U-238, it turns into a new element, plutonium. Plutonium is a fine atomic fuel, just like U-235. In some atomic furnaces there is more fuel at the end of the reaction than the furnace had to start with!

Just look at all the advantages of the atomic power plant: It solves the problem of the disappearing fossil fuels. The plant is almost completely automatic and can be run by just a few men. It saves the cost of shipping heavy fuels to distant places. Some atomic plants make new fuel as they run. Also, the ashes of an atomic furnace are highly valuable for a number of purposes, as you will soon see.

With so many advantages, there is no question that the coal or oil power plant will soon be a thing of the past. It may be that during your lifetime, most of the world's power will come from atomic reactors.

ATOMS FOR TRANSPORT

In the year 1819, the world was agog because a steamship had crossed the Atlantic Ocean. How wonderful it seemed! The ship was called the Savannah. She carried wood and coal for her steam boilers, but the ship wasn't large enough to carry fuel for the 30-day trip. There was steam for the first seven days, and then the Savannah continued under sails.

Today, there is a new Savannah which can travel for three and one half years on one load of fuel! She is called the Nuclear Ship Savannah and her fuel is uranium. Instead of a steam boiler she has a Pressurized Water Reactor.

The Savannah is a beautiful white ship nearly 600 feet long. But when you look at her, there seems to be something missing. There aren't any smokestacks! Of course there aren't any smokestacks, because there isn't any smoke!

The N.S. Savannah has a speed of 21 knots. She can carry 9,400 tons of cargo, 60 passengers, and a crew of 110. On only 700 pounds of fuel, she can take this heavy load around the world 12 times!

Atomic reactors are already in use on ships and submarines and they may soon be used for other types of transportation. Experiments have been made on atomic tractors which would pull long trains of sleds in the Arctic. And there has been some interest among railroad people in atomic locomotives.

The most serious experiments, so far, with atomic locomotives, have been made in the U.S.S.R. That country, because of its vast size, has an unusual amount of freight traffic. Trains now use up one quarter of all the coal and oil produced there. The Russians have completed the design for an atomic locomotive that will have a speed of 75 miles an hour while pulling a load of 4,000 tons. It will travel for almost a year without new fuel, and will go from Moscow to Riga and back (about 1,000 miles) on a piece of uranium the size of a marble!

Designers here and abroad have also started to think about atomic airplanes. One type of design would use a reactor similar to the power plant reactor. It would make steam, the steam would drive a turbine, and the turbine would turn the propellers.

Another design would work on the turbojet principle and wouldn't need steam. Air would be scooped in and heated by the reactor, then shot out of the rear jets, driving the plane ahead.

However, there are serious problems in designing an atomic plane. One of the hardest to solve is the radioactive exhaust that would come from the reactor. All of the waste products of an atomic furnace are highly radioactive and very dangerous to humans. They can cause serious injury or death. People have to be protected from radioactive materials by heavy shielding of concrete or lead. On a plane, of course, the weight of such a heavy shield would create a difficult problem. The shield would weigh more than the gasoline the atomic fuel replaced.

In time, however, there will probably be a solution to the problem, and atomic planes will be made. There will be no worry about running out of fuel. Such things as head winds, long flights across water, and fuel leaks will no longer be threats to the safety of plane passengers. And when the shielding, problem is solved, instead of carrying 50 tons of gasoline, a big plane will be able to carry 50 tons more of people or cargo.

All of these possibilities are just ideas now. But someday, perhaps, you will chuckle over the old-fashioned days before A-trains and A-planes--or, even A-cars!

ATOMS THAT TRACE

Do you remember what isotopes are? They are atoms of the same element, which have different numbers of neutrons in their nuclei (NEWK-lee-eye), the plural of nucleus. Some isotopes, when struck by flying neutrons in a reactor, begin to give off rays, like radium. These isotopes are called radioisotopes.

Some radioisotopes are made on purpose by putting certain elements into a reactor. But many radioisotopes are made in all atomic reactors as a natural product of the chain reaction. After the fuel has been used, the radioisotopes are removed from the ashes.

Most elements have at least one radioisotope and many have several. They have thousands of important uses and new ones are found every day.

There are a few properties of radioisotopes which make them useful. One of them is the fact that they give off radiation and so they can always be found with a Geiger (GUY-ger) counter. This is an instrument which ticks when it is struck by an atomic ray. With the help of a counter, radioisotopes can be used as tracers, or tags.

Tracers are used in dozens of interesting ways. One is to find leaks in pipes. Sometimes there is a leaky pipe buried in the floors or walls of a building. How can you find out where the leak is without tearing the building apart? It is very simple. Just add a tiny bit of a radioisotope to the water in the pipe. Then move a Geiger counter along the floor or wall in which the pipe is enclosed. When the ticks stop--or continue, but spread out over a large area--you have found the leak.

A similar trick is often used in the oil industry. Sometimes the same pipeline is used for oil and for gasoline. A worker at the far end of the pipeline has the job of turning off a valve when the oil stops coming through, and turning on a different valve to send the gasoline to the proper tank. But how does he know when the oil is finished and the gasoline is about to start? There's nothing to it. A dash of radioisotope is mixed with the last gallon of oil. The worker keeps his Geiger counter on the pipe. When it begins to tick, it's time to make the change.

If you had a tire factory, how would you find out which kind of rubber gave the best wear? You could make four different kinds of tires and add a bit of radioisotope to the rubber of each. With the tires on a car, instead of driving thousands of miles, as in the past, you could drive just a short distance. As the tires turned, tiny bits of rubber would wear off. A Geiger counter moved over the tire tracks would tell you right away which tire lost the least rubber. Tire companies use this test widely.

Radioisotopes mixed with wax or polish tell how much is left on a car after washing. Radioactive dirt smeared on cloth tells which detergent does the best washing job. If radioisotopes are mixed with the liquid in a tank, a Geiger counter on the outside of the tank can tell where the top of the liquid is. This is much easier than sending a man all the way to the top of the tank to measure the contents with a dip stick.

Scientists have made great use of the radioisotope carbon-14. Carbon-14 occurs naturally in the air and is taken in by all living plants. It is also taken in by all people or animals who eat plants. Once a living thing dies, however, it does not take in any more carbon-14. Now it happens that carbon-14 has a very long half-life--about 5,000 years. So even if a plant or an animal has been dead for 25,000 years, there are still slight traces of carbon-14 left. By measuring the quantity with a counter and comparing it to the quantity in a living plant or animal of the same kind, scientists can tell the age of very old things.