Command and Control

Louis Slotin was tickling the dragon in a laboratory at Los Alamos, carefully lowering a beryllium shell over the plutonium core of a Mark 3 implosion bomb. The beryllium served as a tamper; it reflected neutrons, increased the number of fissions, and brought the assembly closer to a chain reaction. The clicks of a Geiger counter gave an audible measure of how fast the fissions were multiplying. Slotin knew what he was doing. He’d assembled the core for the Trinity test and performed dozens of criticality experiments like this one. A coworker had asked to see how it was done and, on the spur of the moment, Slotin decided to show him. The core looked like an enormous gray pearl resting inside a shiny beryllium shell. Slotin used a screwdriver to lower the top half of that shell — and then, at about 3:20 in the afternoon on May 21, 1946, the screwdriver slipped, the shell shut, the core went supercritical, and a blue flash filled the room. Slotin immediately threw the top half of the tamper onto the floor, halting the chain reaction. But it was too late: he’d absorbed a lethal dose of radiation. And he, more than anyone else in the room, knew it.

Within hours Slotin was vomiting, his hands were turning red and swollen, his fingernails blue. General Groves flew Slotin’s parents down from Winnipeg on a military plane to say good-bye. A week later, Slotin was gone, and his death was excruciating, like so many tens of thousands at Hiroshima and Nagasaki had been. It was recorded on film, with his consent, as a sobering lesson on the importance of nuclear safety. Three of the other seven men in the lab that day eventually died of radiation-induced illnesses. But Slotin had added years to their lives by thinking quickly and stopping the chain reaction. In the absence of any fast-acting safety mechanism at the laboratory, a report on the accident later concluded, “Slotin was that safety device.”

The same plutonium core that took Slotin’s life had already killed one of his assistants, Harry Daghlian. The previous August, while Daghlian was performing an experiment, alone in the laboratory at night, a small tungsten brick slipped from his hand. The brick landed near the core, which became supercritical for a moment, and Daghlian was dead within a month. Having taken the lives of two promising young physicists, it was nicknamed “the Demon Core,” placed in a Mark 3 bomb, and detonated during a test at the Bikini atoll.

Slotin’s mishap was the fourth criticality accident at Los Alamos within a year, raising concern about the management practices at America’s nuclear weapon facilities. The reactors at Hanford were not only dangerous but largely incapable of making plutonium. Most of the famous scientists who’d worked on the Manhattan Project had left government service after the war. The manufacture of atomic bombs didn’t seem to be a wise career choice, at a time when the world appeared ready to ban them.

In April 1947, David Lilienthal visited Los Alamos for the first time after becoming head of the Atomic Energy Commission. He was shocked by what he saw: rudimentary equipment; dilapidated buildings; poor housing; muddy, unpaved roads — and plutonium cores stored in cages at an old icehouse. Lilienthal was a liberal, one of the last New Dealers in the Truman administration, and he’d seen a lot of rural poverty while running the Tennessee Valley Authority during the Great Depression. But that first day at Los Alamos, he later noted, was “one of the saddest days of my life.” Nuclear weapons were now thought indispensable for the defense of the United States; Lilienthal had expected to find them neatly and safely stored for immediate use. “The substantial stockpile of atom bombs we and the top military assumed was there, in readiness, did not exist,” Lilienthal subsequently wrote. “Furthermore, the production facilities that might enable us to produce quantities of atomic weapons… likewise did not exist.”

The number of atomic bombs in the American arsenal was considered so secret that it could not be shared with the Joint Chiefs of Staff — or even recorded on paper. After visiting Los Alamos, Lilienthal met with President Truman in the Oval Office and told him how many atomic bombs would be available in the event of a war with the Soviet Union: at most, one. The bomb was unassembled but, in Lilienthal’s view, “probably operable.” The president was stunned. He’d just announced the Truman Doctrine before Congress, vowing to contain the worldwide spread of communism. Admirals and generals were fighting over the atomic stockpile, completely unaware that there wasn’t one. “We not only didn’t have a pile,” Lilienthal recalled, “we didn’t have a stock.” The threat to destroy the Soviet Union, if it invaded Western Europe, was a bluff.