Integral Fast Reactor
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
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
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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Update: June 2012