While Peurifoy fought the bureaucratic wars, Bill Stevens and the rest of the nuclear safety department continued to study how to make nuclear weapons less likely to detonate by accident, spread plutonium, or fall into the wrong hands. During the late 1960s, Stevens had begun to worry about a terrorist attempt to steal a weapon, and the massacre at the 1972 Munich Olympics demonstrated that the threat was real. The weapons inside NATO storage igloos seemed the most vulnerable to theft, not only by potential terrorists but also by rogue elements of an allied army or enemy troops. If an igloo seemed on the verge of being overrun, NATO forces were supposed to “spike the guns”—to attach a shaped explosive charge to each weapon and blow it up. A nuclear detonation wouldn’t occur. But the collateral damage could be enormous, and a great deal of plutonium dust might be spread. Stevens thought that better ways of keeping weapons out of the wrong hands needed to be found and that the risk of plutonium dispersal had to be taken most seriously.
Changes were soon made to the storage practices at NATO igloos and to the emergency procedures for destroying weapons. Antiterrorism research at Sandia led to the development of new perimeter control technologies, such as motion detectors, and innovative methods for stopping intruders who somehow managed to get past the door of an igloo. Nozzles on the walls would rapidly fill the place with sticky foam, trapping intruders and preventing the removal of nuclear weapons. The foam looked ridiculous, like a prop from a Three Stooges film, but it worked.
Peurifoy and Stevens also looked at how nuclear weapons should be rendered safe after an accident. The civilians at Sandia and the military personnel in Explosive Ordnance Disposal units often had conflicting notions about what should be done. It was another dispute that pitted scientists in white lab coats against men in uniform. Air Force bomb squads were accustomed to dealing with conventional weapons. And they were trained to get the job done quickly — during wartime, an unexploded bomb near a runway could prevent essential aircraft from taking off. The EOD guys liked to approach a weapon, tear it down fast, and get rid of it. Peurifoy and Stevens thought that wasn’t a good idea with nuclear weapons. A hydrogen bomb that survived an accident reasonably intact could still detonate if someone handled it improperly. Even if it didn’t produce a nuclear yield, the high explosives could spread plutonium and harm anyone nearby.
After the B-52 crash near Cumberland, Maryland, an Air Force EOD team started to remove the weapons from the wreckage of the plane, using improvised heavy machinery — until a representative from Sandia intervened and asked them to stop. The bombs weren’t moved until their condition had been assessed. A naval bomb disposal team began to disassemble the Mark 28 bomb recovered from the ocean near Palomares — until another Sandia nuclear safety specialist made clear that a ship, rolling over swells, might not be the best place for the task. Peurifoy and Stevens thought that, most of the time, there was no need to rush. “Don’t move someone who’s hurt before you know the extent of the injuries,” a basic rule of first aid, also applied to nuclear weapons. Ease of disassembly had never been a top priority among weapon designers. In fact, it was rarely considered when weapons were on the drawing board. Inside the metal casing, parts were tightly welded or glued together. If you weren’t careful, thermal batteries could be ignited, high explosives set off. Peurifoy took an EOD course and gained tremendous respect for the soldiers and airmen who put on bomb suits to render bombs safe. They were fearless. But the weapons they typically handled might kill them and injure people within about a quarter of a mile. Peurifoy didn’t want anyone to feel hurried or gung ho while trying to dismantle a thermonuclear warhead.
The need to retrofit and retire older weapons in the stockpile became more urgent after a discovery about the Mark 28 hydrogen bomb. Stan Spray found that one of the bomb’s internal cables was located too close to its skin. If the weapon was exposed to prolonged heat, the insulation of the cable would degrade — and the wires inside it could short circuit. One of those wires was connected to the ready/safe switch, another to the thermal battery that charged the X-unit. It was a serious problem. The heat from a fire could arm a Mark 28 bomb, ignite its thermal battery, charge its X-unit, and then fully detonate the high explosives. Depending on the particular model of the Mark 28, a blast of anywhere from 70 kilotons to 1.5 megatons would immediately follow.
