Evening star., 1951-12-27

for some everyday industry manu-.
featuring anything from choco-
lates to babies rompers.
Situated in a picturesque SPOT
along the Ottawa river In north.
western Ontario, the plant con.
sists Of 100 buildings spread ovel
300 OF a total Of 10000 foresteo
I>-~->---~-----~->---
1 Second Of Series.
acres-the extra acreage beine
for secrecy. A square, 100-foot
high stone buildings which houses
the heart" Of the Dominion's
project is prosaic enough extern.
ally.
And the device within that
building for producing atomic
energy has roughly the outside ap-
pearance of a vat for making beel
or benzene.
Device Is Unique.
But that device-a so-callec
heavy water" reactor or furnace
is unique among all known
atomic furnaces in the world.
The closed vat-like structure
inclosing this reactor is about IS
feet high and across. It is built In
the center of a room 200 feet long,
100 wide. 100 high.
You hear no sound from the
reactor, but within it
Billions of neutrons - atomic
bullets = are flying around at
speeds up to 10000 miles second,
The radioactivity generated is
equal to that producible by tons
| Of radium.
Each second go trillion neutrons
pass through an area roughly
equivalent to that covered by q
flve-cent coin.
And. it's this concentration OF
neutrons - called the "neutron
fiux" by the slide-rule boys-that
makes Canada's reactor something
super-special.
Makes Plut0nium Faster.
Because Of it. Canada can make
plutonium faster, from a given
amount of uranium fuel than can
any other known country.
The Dominion's present rela-
lively small reactor Is not de-
signed to produce plutonium in
large quantities but the speed fac
tor is there, nevertheless.
Thanks to this same high "neu-
tron flux," Canada's device can
produce radioactive isotopes
"hotter and smaller" than those
producible anywhere else includ-
ing the United States. For ex-
ample, radioactive cobalt for
treating cancer can be prepared
in tiny waters totaling four
ounces, yet packing the radioac-
tive punch Of virtually the entire
world supply of radium.
Secret of Canada's champion
ship so far in the reactor field lies
in the core" of the reactor struc-
ture.
This core Is q cylindrical vessel
about ten feet high and eight
across. In it are 176 uranium metal
rods-the fuel" Of the furnace
and these are immersed in a
special kind Of water called
heavy water"
Keeps Neutrons Busy.
Function Of the heavy water"
is, roughly. to keep neutrons busy
splitting" uranium atoms SO that
a chain-reaction is sustained and
the atomic fire keeps burning.
It's the worlds most efficient
material for that purpose, and it
accounts for the reccrd "neutron
flux" Of Canada's react0r.
The core of the reactor is sur
rounded by q layer of graphite to
reflect any neutrons which might
escape through the water. And,
around this whole inner business
is thick shield Of concrete to pro-
tect workers from radioactivity.
Starting the Chain reaction" in
the uranium fuel is a process of
reverse dunking.
The uranium rods In the CYL
inder are stationary. and there's
enough uranium to maintain a
chain reaction. provided the neu-
irons producible by the fuel are
kept busy splitting uranium atoms.
This is where the heavy water"
comes in. 1t is pumped up from
the bottom Of the cylinder until
it reaches q level where it heads
off sufficient neutrons to keep the
uranium burning"
Water Level Regulated.
Thereafter. the power output of
the reactor can be regulated by
raising or lowering the water level.
It's so sensitive that, to keep a
steady level of power and radio
activity, the water level must not
vary more than a tiny fraction Of
an inch.
An auxiliary means of regula-
ton is provided by an adjustable
control rod" made of cadmium
a metal which has a notorious
appetite for neutrons. and there
fore can take them out of circu-
lation.
The whole shebang can be shut
down by dropping neutron-
absorbing "shut-of rods" into the
reactor. Furthermore, the furnace
shuts off automatically if it gets
too hot.
Materials designed for exposure
to radioactive rays within the re-
actor are fed into the device by
a kind Of ingenious pin-ball
machine.
Substances, like cobalt, to be
"irradiated," are first placed in
tiny aluminium balls, then placed
in special chambers just inside
the reactor.
Through automatic means-con-