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Name: Bethany
Status: educator
Age: 30s
Location: N/A
Country: N/A
Date: N/A

While reading through a back issue of "Discovery" magazine, April 94, I came across an short article concerning the Integral Fast Reactor as a promising "new" technology. What ever became of this technology?

The web site that should be of interest is

K-12 students and teachers will want to view this site as well, and similar related topics at the following web locations:



Would it benefit the United States to share IFR technology with other nations?

There are arguments both ways. Using nuclear energy instead of energy from burning fossil fuels (coal, oil, natural gas) will reduce carbon dioxide emissions into the atmosphere, which is almost certainly a good thing. Using breeder reactors makes the supply of nuclear fuel larger. However, nuclear waste is very unpopular politically in many coutries including the United States, so many people may be angry with the US if it helps other countries use more nuclear power.

Is it likely that other nations would use it?

IFR is a better, safer reactor design than most reactors now in use. There are many new reactor designs that are better and safer than anything now in use for power production. Nations that build new reactors will probably use some of these newer designs, possibly including IFR.

Is the IFR considered renewable?

It isn't renewable in the sense that you can plant seeds in the ground and grow nuclear fuel from them. However, as a "breeder" reactor, it does make plutonium 239, which can be used as nuclear fuel, from uranium 238, which cannot be used as a nuclear fuel.

Can it recycle its wastes?

Just the plutonium and heavier elements. Some wastes, such as fission products, need to be removed and disposed of. However, this is a tremendous advantage over conventional nuclear power plants, as the components of the spent fuel that are the most hazardous over the long term are used as fuel, converting them into less hazardous materials and getting energy from them is the process.

Is the IFR safe? What safety tests have been run?

The passive safety characteristics of the IFR were tested in EBR-II on April 3, 1986, against two of the most severe accident events postulated for nuclear power plants. The first test (the Loss of Flow Test) simulated a complete station blackout, so that power was lost to all cooling systems. The second test (the Loss of Heat Sink Test) simulated the loss of ability to remove heat from the plant by shutting off power to the secondary cooling system. In both of these tests, the normal safety systems were not allowed to function and the operators did not interfere. The tests were run with the reactor initially at full power. In both tests, the passive safety features simply shut down the reactor with no damage.

The fuel and coolant remained within safe temperature limits as the reactor quickly shut itself down in both cases. Relying only on passive characteristics, EBR-II smoothly returned to a safe condition without activation of any control rods and without action by the reactor operators. The same features responsible for this remarkable performance in EBR-II will be incorporated into the design of future IFR plants, regardless of how large they may be.

Can IFR wastes be used in nuclear weapons?

The IFR recycles all the elements it makes that can be used in nuclear weapons, so they don't go into the waste stream.

What is usually used?

Nuclear weapons require "fissile" nuclei, which split apart, releasing energy and neutrons when contacted with slow-moving neutrons. Thge three "fissile" nuclei that I know of are uranium-235, uranium-233, and plutonium-239. Uranium-235 is obtained by painstakingly purifying ("enriching") it from natural uranium which is about 0.71% uranium-235. Uranium-233 is made from thorium-232 by bombarding it with neutrons. Plutonium 239 is made by bombarding uranium-238 with neutrons. This happens in nuclear reactors, because most of the uranium in nuclear fuel is uranium 238.

If not, could it be processed to be usable for weapons?

The actual waste from IFR would be useless for making weapons. However, IFR fuel must be removed periodically to be reprocessed, to take out the waste materials that interfere with the nuclear reaction. (IFR consumes much more of the fuel before these wastes cause a problem than conventional reactors can.) This spent fuel could, in principle, be further processed to isolate the fissile materials that could be used in a nuclear weapon.

What kind of facility would this take?

A very expensive facility with lots of radiation shielding using remote handlers and robots to do the actual work. If someone were to steal some spent IFR fuel, it would have to be heavily shielded just to carry it away or it would kill everyone nearby. Processing would require special equipment and large quantities of specific chemicals. It would be impossible to hide. (Which is why Iraq doesn't want international inspectors to check for signs of a nuclear weapons program - the evidence is very hard to conceal.)

Richard Barrans Jr., Ph.D.

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