Atomic Hot Spot

The U.S. press, eager but uneasy, got its first look last week at a uranium pile in operation. The occasion: the sale at Oak Ridge of a pile-made radioactive isotope, produced as a peaceful by-product of atom bomb plutonium.

Enclosed in a white-and-green building the shielded pile looked like a mighty concrete block. A red light warned that it was working. Behind the massive walls, a blizzard of darting neutrons was smashing atomic nuclei, creating hundreds of radioactive isotopes so "hot" that invisible specks of them could kill. All around were vigilant Geiger counters ready to raise the alarm if too much radiation leaked. But the only sound was the hum of the ventilating system carrying deadly gases up the stack.

Inclosed in graphite blocks inside the pile, aluminum cans of various chemicals were being exposed to neutrons, which transmuted some of their atoms into radioactive isotopes. To extract such a can, the pile must be shut down by remote control lest a beam of neutrons follow through the aperture and wipe out the operators.

A scientist called the control room: "Check the electrical circuits."

"Check the electrical circuits," echoed a loudspeaker.

Then the scientist nodded to TIME's correspondent. "Turn the switch." The switch looked like a valve on a gas stove, it turned easily. Control rods (probably of cadmium) clanged into place. They soaked up the vital neutrons faster than they were produced from the uranium. The pile stopped.

Then a heavy lead "coffin" rolled up the wall. Into it dropped an aluminum can to be taken to "hot cells" with yard-thick concrete walls. There, working with periscopes and tools which reached around corners, chemists would extract the isotopes it contained. All workers wore loose canvas covers over their shoes so that no "hot" particle could lodge in the leather and gnaw a dangerous lesion in their feet. The laboratory tables were topped with three-inch slabs of lead. Neatly stacked lead bricks gave additional protection to workers.

Some of the chemicals were mild enough to handle with long tongs. But every object was checked and rechecked with Geiger counters. Even a piece of glassware that looked entirely empty might be "hot" enough to kill.

The reporters filed out, glad to see that the pleasant green hills of Tennessee were not yet radioactive.

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