Van Dyckman answered stiffly, “Hydra Mountain meets all DOE standards, which are far more stringent than the older military requirements. The two layers provide a high level of redundancy.”
Victoria Doyle finally joined in the conversation. “The DoD and the DOE have different ways of handling nuclear material. The DoD is the end user of nuclear weapons. They don’t build them; that’s the DOE’s job—”
Van Dyckman cut her off. “The Department of Energy designs and manufactures nuclear weapons, conducts research using nuclear reactors, and so they have to deal with the waste generated by those operations. Both departments have outstanding systems for nuclear safety and security, but they are different, and we had to account for that difference when Hydra Mountain was transferred from the military to the DOE.”
“Well said.” Mrs. Garcia was cheery but uninterested in the discussion, hurrying them along so she could do her part. “Let’s go inside and have a look.” She entered a code in the keypad next to the old-fashioned intercom outside the vault door. “This is a typical chamber where we now store dry high-level waste.” As the door moved, a magenta light flashed at the ceiling and an alert buzzer sounded in the tunnel. “Step back, everyone.”
As the thick metal vault slowly rotated open, Mrs. Garcia pointed at the line of similar oval doors staggered at intervals down the long tunnel. “Back in the day, when the military stored warheads here, each vault was staggered to make sure that stray radiation from one device couldn’t interact with others. Fail-safe systems ensured that when one chamber door was open, all the other doors had to be sealed. That kept any radiation from getting inside—”
“But Hydra Mountain’s mission has changed,” van Dyckman interrupted. “So we modified these systems to hold high-level waste, which can’t go critical like a nuclear weapon.”
Harris added in his bland voice, “Because of the schedule imposed, we needed to open more than one chamber at a time just to accommodate the volume of material we’re bringing inside. Otherwise, we could never keep up, and shipments would pile up in the main corridor staging area, causing an even greater hazard.”
“We wouldn’t want to slow things down, now would we?” Garibaldi said in a biting tone.
Adonia frowned at the site manager, surprised that “Regulation Rob” would bend the rules. “You modified the systems so you could open multiple chambers at the same time, in order to move in more shipments as they arrived.”
“You know the sheer amount of backlog in our nuclear facilities,” van Dyckman said. “The faster we ease the pressure on power plants like Granite Bay, the safer the nation will be. And we have all these empty vaults just waiting to be filled.”
“We keep receiving shipments,” Harris said. “It seemed the best way, and calculations showed a significant safety margin in these specific vaults.”
Harris had a fine reputation at DOE, and he had even mentored her when she’d been a young intern at Oakridge National Laboratory, working on her first reactor. But now his hair was thinning and much grayer than she remembered; his face was lined with stress. He seemed to be going through the motions, following the rules without any passion for the work. She hadn’t realized at first, but now she saw that he looked old. And worried.
Mrs. Garcia waited patiently as the vault door ground all the way open. “Wait here while I do my safety check. Don’t go inside yet.”
Adonia and her companions crowded up to a bright yellow line painted on the floor just outside the entrance. Inside the large chamber, alcoves had been carved into the inner granite walls, each twenty feet high, ten feet across, ten feet deep. A yellow rope hung across each cubbyhole. Like a sarcophagus, a metal cylinder marked with the universal yellow radiation symbol stood upright inside each alcove.
“Those are dry-storage containers,” Adonia said. “Granite Bay is overflowing with them.”
“Those alcoves were originally designed to hold nuclear warheads, each separated by two feet of granite. That’s more than sufficient to absorb any line-of-sight radiation emitted by plutonium cores,” Harris said. “Or in this case, more than enough to shield high-level nuclear waste.”
Garibaldi seemed reluctant to move near the chamber. “What’s the ambient radiation in there now?”
“Negligible,” van Dyckman said reassuringly. “The containers themselves have sufficient shielding. It’s overkill, believe me.”
“It’s naïve to say that any radiation is negligible,” Garibaldi growled, looking at Harris as if they shared some kind of secret. “Right, Rob?”
The site manager balked, but refused to answer. Adonia got the impression this was an old argument — from all the way back at Oakridge?
Senator Pulaski peered inside. “Look at all that shielding rock. Opening two vault doors at the same time couldn’t possibly be a safety hazard. Or am I missing something?”
“It used to be,” Mrs. Garcia said, “when nuclear weapons were stored here. But now that they’re gone, there’s no kill zone surrounding the Mountain.”
“That’s overstating it,” van Dyckman sighed. “She means a possible contamination area.”
“No, she means a kill zone,” Garibaldi said. “It’s the area around a nuclear explosion where there’s total destruction of human life. Hiroshima’s kill zone had an average diameter of one point six miles, and that blast was ‘only’ fifteen kilotons. If the conditions are right, a megaton’s kill zone can reach sixty-three miles across — an area of over three thousand square miles. That’s why these doors were never opened at the same time.”
“Let me show you the principle, Senator,” Mrs. Garcia said, sounding like a schoolteacher. “Watch me.”
She stepped back into the corridor and walked fifty feet to the next sealed storage chamber. “Suppose this vault door were open. Now pretend I’m radiation emitted from a nuclear warhead stored inside.” She crossed the tunnel and stopped at the granite wall on the opposite side, slapping it with her hand. “Most of the radiation is absorbed, but some of it — me, in this case — will reflect off the wall and bounce down the corridor.” She walked back toward the group in a zigzag pattern, “bouncing” from one side to the other.
“Now imagine billions upon billions of particles either being absorbed or reflected, following a similar path.” When she reached the group of observers and the open vault door, her trajectory now headed straight toward the open chamber. “Eventually, some of the radiation could find its way in among the warheads, where it would bounce around and interact with the cores—”
“And possibly initiate a catastrophic chain reaction,” Garibaldi said. “A nuclear detonation that would ruin everyone’s day.” He looked around. “It’s a small probability, but with enormous consequences.”
“Worse than that.” Doyle spoke up, surprising them after her long silence. “In a warhead storage area, since the weapons are so close together, it wouldn’t be just one detonation. The radiation from each device might initiate another cascading explosion… and another… and another. It’s called sympathetic detonation — the absolute worst-case scenario.” She glanced at Harris.
“You’re right,” Garibaldi said. “Multiple megaton explosions even deep inside Hydra Mountain would result in a kill zone hundreds, if not thousands of miles in diameter, perhaps extending to the East Coast.”
Van Dyckman lifted his chin. “But of course that can’t possibly happen now, since we’re only storing waste here, not warheads.” Undersecretary Doyle seemed to be raining on his parade. Adonia recalled their alleged affair; the two probably considered each other competition now. “Nukes haven’t been stored in Hydra Mountain for decades. This is the safest SAP the government has ever run, and I will keep it that way.”