Idaho Falls Page 15
The command center at Highway 20 and Fillmore Avenue.
As larger pieces of machinery were hauled out of the building and the steel walls and ceiling were torn down, radiation levels in the yard around the site began creeping to unacceptable levels. Officials considered trucking the radioactive waste to what the Testing Station called the Burial Ground, the final resting place for all the site's really bad stuff. But it was a sixteen-mile journey, partly over public Highway 20. Carrying dangerous cargo over such a heavily trafficked road posed too much risk. And it would mean too much exposure for the drivers. Instead, two large pits and a trench were dug among the sagebrush, about sixteen hundred feet from the SL-1 compound. Over the course of the sweltering summer and into the fall of 1961, a dump truck, its driver protected by lead sheets, hauled the remains of the reactor into the desert. The debris filled fifteen hundred feet of gouged earth. Bulldozers kept piling dirt into the pits until a health physicist no longer picked up radiation readings with his detector.
In November, a huge crane lifted out the soul of SL-1: the engine, what nuke workers call the pressure vessel. As the core was hoisted from the decapitated silo, workers silently looked on, wondering how such a small structure—just fourteen and a half feet tall and four and a half feet in diameter—could have caused so much destruction. The freed core was slipped into a tall steel container which was waiting on the back of a flatbed truck. It was hauled slowly, with a security escort, to the Hot Shop.
C. Wayne Bills, the AEC's deputy director of health and safety at the Testing Station, had been appointed to oversee the work of the technical group in charge of probing for the cause of the SL-1 blast. He says it was the removal of the reactor core that allowed scientists and engineers to fit the final pieces of the puzzle together. It would take them almost a year, but the technical investigators eventually ruled out some of the leading theories proposed in the first weeks after the explosion. Tests showed that the reactivity of the core had not changed appreciably over the Christmas shutdown as site personnel originally thought. This finding seemed to rule out speculation that the reactor was unstable and on the verge of criticality on the night of January 3, needing only a few inches of control rod movement to explode like some gag cigar.
Bills's group also ruled out the possibility that the explosion was anything but a nuclear excursion. Despite initial radiological evidence that a nuclear event had taken place within the SL-1 silo, there were a few holdouts at the Testing Station who thought another force could have been responsible for the blast. Earlier, the AEC manager of the Idaho site wrote a memo to one of his bosses in Washington, DC, asking that the FBI be brought into the investigation. Allan Johnson wrote, “Although there is no evidence for support, we are thinking about sabotage possibilities.” The memo was forwarded to the investigation committee, but the chairman couldn't get a consensus on bringing in FBI agents—with the inevitable bad publicity that would result. Instead, the committee hired private explosive experts, who worked quietly, away from the public and media's eye. T.C. Poulter of the Stanford Research Institute eventually eliminated the possibility of an explosive charge having been placed in the reactor: “There was no sabotage involved in this event . . . which could have been caused by a chemical type of explosion.”
But after months of sifting through debris pulled from the reactor, the technical team uncovered some concrete, telling clues. One of these clues, the finely machined central control rod, had been lying in the Hot Shop since the first days of the investigation. But it took some time to crack its secrets. The top part of the rod, called the rack, was still wrapped in the metal sheath in which it traveled up and down. The rack was stuck in the sheath, with just four inches protruding: exactly the height it should have been if the crew was reconnecting it correctly to the drive mechanism. “When we found it seized in the right place, we thought, ‘Gee, there must have been an explosion down in the vessel that blew the center rod out.' We were still very much in a quandary,” Bills explains.
The SL-1 reactor is removed.
Some time later, the members of the team were looking over debris recovered from the fan room, a small area located directly above the reactor. A nondescript length of pipe caught their attention. It was the straight pipe that crews attached to the top of the rack to lift the control rods. Attached to the pipe were a nut and washer and a bit of the rack. It had obviously been blown through the ceiling by the explosion and had lain there for months. And it spoke volumes to the engineers: It was the clue they'd been looking for.
“When the handle got thrown into the attic, it was a missing piece of evidence,” Bills says. “We didn't really know what part of the operation the crew was in. When we found the handle and discovered it was hooked above the washer and the nut, we knew they were in the final stages of assembly, [when] you were only supposed to raise the rod a quarter of an inch. You weren't even supposed to raise it four inches.”
The discovery meant Legg's crew had, sometime before the blast, already raised the control rod—the delicate part of the operation—a bit more than four inches and installed the C-clamp to hold it temporarily. The handle was then removed and a nut and washer installed to connect the control rod to the drive motor. The evidence indicated that that work had been done and the handle reinstalled. The crew simply had to take pressure off the rod to remove the clamp. At that point, they were just a quarter-inch lift from a routine night and likely long, prosperous lives.
Bills and his team turned their attention back to the control rod, still highly radioactive. Could it be hiding the explanation for what had happened in the millisecond before the explosion? They decided to dissect it by cutting away the sheath. There, inside, on the normally smooth surface of the rod, they found scratches. Those marks would forever damn at least one member of the SL-1 crew on duty the night of January 3.
From a methodical examination of the piece of equipment, Bills's team was able to make a certain deduction: “The central control rod had been jerked out,” he says. “The first scratch is when the thing is pulled out twenty inches. It was then blown up to the ceiling and hit a beam. That's where the handle broke off and the rod was driven all the way back into the sleeve. When the rod came back down and hit the reactor vessel lid, the rod was driven back up to four inches, exactly where it should have been. Until we cut the thing apart, we didn't know it had been out to twenty inches and we didn't know it had gone back to zero. It had scratches back down to zero and then scratches back up to four inches. I almost got away with saving that piece, but it was still radioactive. I couldn't talk them into saving it, but that was a real gem.”
The discovery proved that one of the crew members had suddenly pulled the central control rod out twenty inches. Although there was no other plausible explanation, it seemed inconceivable to investigators. There simply was no reason to ever pull a rod out that far. And the technical team now knew the rod had already been withdrawn four inches with no problem and that it only needed to be eased back down. That seemed to disprove the theory put forward by some SL-1 cadre members that the rod must have stuck when it was first being lifted, forcing the crewman gripping the handle to pull up on it too hard.
From the official interim report.
Still, Bills's team decided to do one more test. It built a mock-up of the reactor top, complete with a dummy control rod weighing about the same as the one found in SL-1. Team members then positioned men below the mock-up to hold the control rod, mimicking the resistance a crewman would feel if the rod had stuck. Men of all sizes and strengths were brought in and told to grab the lifting handle and pull as hard as they wanted. As each yanked up, the control rod would be suddenly released from below, as if a sticking rod had just let go. Not one of the men pulled the rod far enough before stopping its upward progress to have created a nuclear explosion.
“They would only override by maybe ten inches or so,” says Bills. “No one got to the twenty-inch mark. I don't think you'd overshoot it that far. Once
the rod went over fourteen inches, the reactor went prompt critical. The fact that it went to twenty inches was incidental. By the time he'd gone up to twenty inches, the reactor was going.”
By that time, Bills had been tipped off about Legg's reputation as a prankster with a penchant for horseplay and wrestling. Though it seemed like a ludicrous experiment, Bills felt compelled to confirm that the world's first nuclear reactor deaths hadn't been the punch line of a joke gone terribly wrong . “We looked at goosing,” he says. “You know, someone grabbing the guy on the rod in the rear and having him jump.”
In what must have been yet another surreal SL-1 scene, one volunteer after another stepped onto the mock-up reactor, began pulling up on the rod, and was given a goose—a poke in the butt—delivered as unexpectedly as possible under the conditions. Not one of the men jumped or jerked or yanked hard enough on the rod to raise it anywhere near the critical fourteen inches. And good thing, too—the whole affair was shaping up badly enough as it was; it wouldn't do to discover the gruesome deaths had been the result of a prank. Still, it was only marginally good news, because for Bills, his team's finding could only mean one thing.
“It all came down to the center rod being pulled up too far by a crewman,” he says. “I don't think you'd overshoot it like that. The fellow could have stopped it if it wasn't some kind of just deliberate ‘to hell with it' action.”
By the time Bills figured out what had happened mechanically the night of January 3, Don Petersen and the autopsy team had figured out who had done it. The team had returned to Los Alamos knowing how each man died—from multiple traumas—but they needed those horrific wounds to tell them a story: Who was where and doing what when the blast ripped the silo apart? Lushbaugh and the other doctors thought they had figured it out based on the injuries they had observed, but they looked to Petersen to confirm their hunches. During the autopsies, the biologist had been collecting hair samples from the victims: from their legs, groins, arms, and heads. The scientist knew that human hair is 5 percent sulfur by weight and contains no phosphorus. But the neutrons coming out of the rendered reactor top would have produced phosphorus 32, a radioactive substance with a known rate of decay, losing half its radioactivity in fourteen days. By determining the relative intensity of the phosphorus clinging to the hair samples, Petersen could approximate where the men were and make guesses about what they were doing based on the path of radiation up, down, and across their bodies.
Between Petersen's findings, Lushbaugh's three-dimensional study of injuries, and the technical team's analysis, a compelling picture of what was happening on top of the SL-1 reactor just before 9 P.M. on that January night was finally coming together. Dick Legg's crew appeared to be running behind in its work. The men were supposed to connect four of the reactor's five control rods; the fifth was a dummy that had remained bolted in place over the Christmas shutdown. But three hours before shift change, the crew was still working to latch its first control rod, the central one, designated number nine. The central rod had already been eased four inches out of the reactor core and had a C-clamp attached to hold it in place. One of the crewmen had then spun the lifting tool off the top of the rod so that a colleague could install a washer and nut, connecting the rod to the drive motor. A crewman had then put the lifting tool back on. At 9 P.M., chief operator Legg squatted down on the reactor top, straddling the rod motor for control rod seven. The position put him close to the bottom of control rod nine, where he could easily slip off the C-clamp. Jack Byrnes stood next to the port that housed the central control rod, in a position to gently ease the rod up to relieve pressure on the clamp. Trainee Richard McKinley was just off the reactor top. He was turned toward the other men, with his left leg and arm nearest the reactor.
Diagram taken from the official interim report.
At 9:01 P.M., Jack Byrnes pulled the hundred-pound central rod upward, strong and hard and in less than a second. The poison cadmium on the bottom end of the control rod—the barrier that had put the reactor to sleep two weeks earlier—slid out of the uranium fuel cells deep in the reactor's core. Like a hive of killer bees, neutrons in the uranium atoms swarmed instantly, colliding with one another, creating even more neutrons. In nanoseconds, there was an uncontrollable chain reaction which created enormous heat. At 3,740 degrees Fahrenheit, the uranium 235 fuel vaporized and created a fist of steam deep in the core. The steam rushed upward at tremendous velocity, aided by a two-foot void in the core—the water level had been dropped two feet over the holidays to aid in maintenance procedures. The water hammer slammed into the top of the heavy steel reactor top like a punch from a champion heavyweight. The blow lifted the nine-ton reactor core nine feet into the air, shearing off water lines that carried cool water in and radioactive water out, and spewing gamma, beta, and alpha radiation. Control rods, shield plugs—anything covering the ports of the reactor—became deadly missiles and shot upward at near-supersonic speed, powered by the rush of water and steam.
By the time the reactor vessel slammed back down into its hole, Legg had been impaled in the stomach and chest by control rod seven and hurtled into the ceiling. The autopsy report says death came “instantaneously from the destruction of his viscera by rapidly expanding gases that penetrated his abdominal cavity along with a heavy missile.” Byrnes had been thrown back into one of the concrete shielding blocks, breaking ribs that pierced his heart. McKinley had been struck hard in the head by a piece of flying shrapnel, had his face torn off, and his left hand ripped from his arm. He lived for two hours, but he was in deep shock and never regained consciousness.
“It was all over in a matter of microseconds, certainly microseconds,” says physicist Condit. “Those guys would never have known. That shock just happens . . . like that. It's all over before you see it.”
And at 9:02 P.M., it was all over indeed.
The reenactment of that hellish second seemed to answer who was where, what they were doing, and what initiated the explosion. It seemed to further absolve Legg, the prankster boss, from a clearly not funny nuclear faux pas. But it implicated Jack Byrnes, the angry, distraught, disillusioned operator. The scenario made sense, technically and spatially. But it failed to explain one-tenth of a second that January night: What went through Jack Byrnes's mind in the moment before he tensed and pulled? What was his motive?
Bills says that when his technical group and the autopsy team presented their findings to the investigation committee, there was an immediate response from its members, a response that would augment the wild rumors already circulating within a small group of nuclear workers: “Although they [the committee members] had done some investigating beforehand into the relationships of the people, the AEC's Division of Inspection went back again and really penetrated to see if they had missed something in those relationships that would explain violence, or maybe psychological things that were going on.”
By that time, the committee had received off-the-record information about the crewmen's personal lives, as well as having heard some stories—unsettling ones. Those stories prompted them to investigate a potentially sensational angle to the story, one that could be summed up in three words: crime of passion.
* * *
Unbelievably, the world has never discovered—at least not from the committee—what its members learned about the crewmen's personal lives or how they thought that information may have impacted on what happened inside the SL-1 silo. Twenty-one months after the nuclear deaths, the investigation committee released its final report. It condemned the supervisors of the SL-1 project—from the civilian contractor to the military to the Atomic Energy Commission itself. But it said that ultimately these supervisory bodies were not to blame for the explosion. The committee pointed out serious operational problems that had been allowed to fester, including the loss of boron and the sticky control rods. But it said that those conditions had not precipitated the nuclear excursion. It found the training of the SL-1 crews seemingly inadequate. But it said lack of train
ing did not play a role in the blast. It deemed the design of the reactor—its ability to go critical with the pull of just one rod—flawed. But it said that didn't lead to the deaths of the three young men.
The committee's report never mentioned the crewmen by name, nor did it identify who was doing what when the reactor exploded, nor what injuries they sustained. The report did not address the servicemen's personalities or psychological states of mind, their work capabilities, or their home lives. As persons, they were missing entirely from the document.
Instead, the board penned just two vague paragraphs that would have to pass for an acceptable official answer to the SL-1 mystery:
The direct cause of the incident clearly appears to have been the manual withdrawal by one or more of the maintenance crew of the central control rod blade from the SL-1 core considerably beyond the limit specified in the maintenance procedure.
The reason or motive for the abnormal withdrawal is considered highly speculative, and it does not appear at all likely that there will ever be any reason to change this judgment.