He Gives the Word

Eleven times in the last 50 days, one man at Yucca Flat, Nev. has given the word to set off an atom blast, and at least 50 times he has postponed explosions. He is Dr. Alvin Cushman Graves, 46, scientific adviser to the test manager. Dr. Graves must be satisfied that all Atomic Energy Commission safety requirements have been met. For example, the AEC has ruled that nearby towns such as Las Vegas, Tonopah, Indian Springs, Caliente and Paradise Valley shall not receive more than 3.9 roentgens* from radioactive fallout within any twelvemonth, a figure far below a commonly accepted danger point of 25.

Graves is a physicist who has lived in the strange world of atomic experiment most of his adult years. He has been at Los Alamos since 1943. His wife is an atomic physicist, and of her work Graves says: "I've been doing so much administrative work and so little research in the past few years that she has passed me so far I sometimes don't know what she is talking about." But the reason he especially understands the extra need for caution during nuclear tests is a personal one. He once stood a foot from atomic death. In 1946 he was working at Los Alamos with a young physicist, Louis Slotin. Something went wrong with Slotin's experiment and he absorbed 800 roentgens in a split second, dying seven days later. Graves, who was right behind him, absorbed 200 roentgens and survived. Today his left eye is cloudy from a radiation cataract.

Half-Globe Weather Report. At Yucca Flat Graves sorts out hundreds of requests and reports from military, research and civil-defense agencies. Twenty-four hours before a test is scheduled, he meets with 100 members of the staff in a windowless, rectangular room. Dress ranges from khaki to cowboy shirt, but there is strict attention when the meteorologist starts to talk.

A weather report on half the globe is read, then the weatherman narrows down to the continental U.S., finally gives a mile-by-mile analysis of the weather expected over Yucca Flat at test time. Each forecast of precipitation, the wind up to 50,000 feet, and temperature is illustrated on charts and defended under a scientific inquisition. Its object: to assess the danger from radioactive fallout. After the weather discussion, Graves questions scientists in charge of each phase of the prospective test. "Are your experiments in order?" "Are you satisfied your setups are O.K.?" Each nods his answer, and Graves makes his first decision: the test is scheduled for the next day.

Then Graves roams the 640-sq.-mi. test area in his oyster-white, radio-equipped Chevrolet or his helicopter, asking questions, weighing the answers. While 30 to 35 meteorologists check and recheck the wind to see if there is any hint of a change, half a hundred safety officers in cars and helicopters search the wasteland to shepherd flocks of sheep or lonely prospectors out of the danger area.

Head-Scratching Time. At 9:30 that night, 50 men meet with Graves for 45 minutes. More detailed weather maps and the latest weather reports are presented. The product of a battery of electronic calculating machines, which have been fed a vast assortment of statistics on weather, explosive force and other factors, are produced for digestion and decision. Each key man in the room gives his opinion. Then Graves turns to eight top-level scientists in the first row--among them ballistic experts, meteorologists and health physicists. "They usually mumble that they believe we should go," says Graves. "Then I scratch my head, think a couple of minutes and turn to Jim Reeves, the test manager, and say something like 'Let's go.' "

Now the tension begins to grow. Graves can change his mind up to one second before the explosion deadline, but he has already given the word that sends between 30 and 160 aircraft up for blast observation and cloud sampling. The word has been flashed to the Strategic Air Command so that planes in Seattle, Florida and overseas can take off on related atomic surveillance missions. His word has warned the Civil Aeronautics Administration to keep planes out of certain areas across the continent.

Cheese Was No Lure. This is the time to expect the unexpected. Desert jack rabbits like to feed on insulation. Once a kangaroo rat was found nesting in an essential instrument at the last minute. An atomic engineer tried to lure him out with cheese, but kangaroo rats don't eat cheese. Hundreds of nervous technicians waited until one found out how to catch a rat. In the lonely hours between midnight and 3 a.m., Graves is still checking, between catnaps and gin rummy games. To help predict the blast effects of each atomic explosion, World War II Navy depth charges containing 2,400 Ibs. of TNT are exploded two hours and one hour before zero hour. In the morning, when Graves gives the order, eight scientists ride an elevator up the tower to the device cabin to arm the explosive device. They report each move by telephone to Graves in the command post. A checklist of from three to eight pages long is read aloud in the 20 minutes it takes to get the device ready--and the eight men can ride down the elevator to safety.

Then the Red Button. Sirens echo over the desert, and, all alone, Graves makes the last decision. He gives the word to push the red button. Machines take over. A cam closes a switch and power is fed to cameras, test instruments and power plants. Red and green lights on the control panel trace the action from sequence to sequence. Nothing is left to human error. Even the voice that intones the final count over the loudspeakers on Yucca Flat has been recorded on a tape that cannot blow its lines from human emotion. Electric current travels a full 15 minutes through a maze of relays, switches, condensers, coils, filaments and generators. There are safety checks along the way, fuses and other devices that can take back Dr. Graves' decision up to half a second before the zero second, but if all goes well, the current at last rams into the device, and a mushroom cloud stands miles high over the concrete bunker where Dr. Graves gave the word.

* In a routine chest X ray, a patient absorbs about 0.05 roentgen.

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