In two minutes Number Four had been checked out in working order. The a.n.a.lysis concentrated back to Number Three pump.

"I'm getting a steady pile reading," the board man reported, "as a matter of fact, it's running a little hot. But no response to damping effect. She's running wide open."

"Yeah," the section chief muttered as his eyes shifted along the array of scopes on the panel, "I see that, but why aren't we getting any head pressure?"

The board men continued to run new series of response checks on the rest of the pump system. Outside, the head of the heavy equipment convoy came to a halt and the crews climbed out to wait beside their vehicles.

Five minutes later the board men finished their checks and then conferred briefly with the section chief. He came over to the engineers.

"I think we've got your answer," he said glumly, "but I don't think you're going to like it. The best we can figure out is that the shock must have created some kind of a lag turbulence down there and when it was over the water piled into Number Four and slammed it over on its side. Or maybe the shock just tipped it over. In any case, it's either clogged the intake or jammed the nozzles. We don't know which. And it's jammed the dampers."

"So," the hydraulics chief shrugged, "we put another unit down there."

"It's not that simple, Mr. Hall," the monitor chief continued. "That pile's running wide open and no place to go. It's got to be stopped or she'll blow right outta there. And if Four goes--blooey, there go the other three."

The chief engineer sagged. "No chance of getting the dampers to respond?"

The monitor man shook his head sadly.

Hall ran his hand tiredly over his face and stared silently at the flickering oscilloscopes as if to force the damping device into functioning by sheer will power.

He sighed and straightened up. "All right," he said, "how do we shut it off. Is there an outer manual system?"

"There is," the monitor chief replied, "but in all likelihood it's jammed, too, by the shock or tip-over--and I'm more inclined to buy the tip-over than anything else."

"Any other way to shut it down?" Hall queried.

"Just one," the chief said. "Blow her apart chemically before she goes critical. And that, chief, is a real tough one. Someone's got to go down there and clamp some plastic blocks in the right place on the pile housing. Even then, there's the chance that she might blow in the wrong direction and the whole shebang will go up in big, fat mushroom cloud."

Hall's eyes saddened. "If that's it," he sighed, "that's the way it has to be. Let's get with it. Where does the plastic go?"

[Ill.u.s.tration]

"Better check that out with Barton in the main rig," the monitor chief replied. "He's got the prints and he can show you the exact spot on one of the spare pumps. Oh, and Mr. Hall," he paused, "you'd better hurry it up. She's leaking a little of the pressure down there but not nearly enough. I'd make a quick guess and say that we've got less than two hours to either shut that pile down or relieve the pressure.

And if she's tipped, the time in getting it back up and checking out damage on the pump system is going to take too long and it might not be repairable. The best bet is to blow her."

Hall nodded and with Harbrace and the junior engineers in his wake went to the central pump section vehicle.

Walking to the other vehicle, Alec looked at the water with stricken eyes. "G.o.d in Heaven," he said aloud, "I never thought it would end this way."

Harbrace broke stride and took Patterson gently by the arm.

"None of us did, Alec," he said. "This isn't your fault. You had a fine idea and it worked. What happened afterwards is no worse than the original quake that caused the damage. If this thing blows out, we won't be out any more water than we would have been if you hadn't come up with the idea in the first place."

"That's not what I meant," Alec said in a shaken voice. "If this does blow out, not only do we lose the water but we're going to contaminate this aquifer with radioactivity from here to the mouth of the Columbia."

"I know that, too," Harbrace replied softly. "It's still not your fault, son. And we're not licked yet. Come on."

Twenty minutes later, a double strand of durasteel cable stretched across the three-hundred-foot wide current, suspended between the raised crane towers of four of the mammoth crane carriers and pa.s.sing twenty feet above the churn of the bore hole.

Hall and a half dozen of his section chiefs stood at the base of one of the makeshift towers. The chief hydraulic engineer had a headset clamped on for contact with all the working units.

He turned to one of the men standing by. "Get me a pressure reading on that hole," he ordered. "I want to know how much weight it's going to take to get down through that mess."

"Why not just shut the other three down while we go down into the hole?" the a.s.sistant asked.

"Calculated risk," Hall said. "If she's going to blow, it isn't going to make any difference if the others are shut down or not. And, if we can keep pumping while we're working, we're staying ahead of the flow from the reservoir. Get me that reading."

The pressure report was back in minutes. "It'll take at least a four-ton ma.s.s to get down there fast and keep from being bucked around."

Hall looked around, "What have we got that's small enough and has that weight or better?"

"How about a van tractor?" one of the supervisors suggested. "They weigh closer to six tons but they're pretty compact."

"Fine," Hall snapped. "Rig it."

The bulky, almost square, tractor was rolled up and the rigging crews were swarming over it, clamping suspension cables from the running pulley that would ride the cable across the current.

"What's the radiation report?" Hall asked monitoring.

"Still building," came the reply. "But we've got a leak somewhere, Mr.

Hall. We're getting readings from the water down there. Not too much yet, but it may change our time factor. I'd either get on it fast, chief, or let's get outta here. That thing can go any minute now."

The tractor was rigged. Hall turned and bawled, "Where are those divers?"

Alec Patterson and Troy Braden stepped out of a nearby van, dressed in pressure suits and tanks, their helmet flaps open. Alec had a heavy belt of ultra-high explosive plastic lashed around his midsection.

Troy carried a rack of small clamps strung across his shoulders.

"Where do you think you two are going?" Hall roared. "Get those suits off and get outta here."

"Shut up and listen," Alec snarled. "I started this. I'll finish it.

This idiot partner of mine hasn't got any better sense than to go along. We haven't time to argue, so just listen.

"Both of us have been trained in hydrology and have made many dives before. We've both used this plastic and we've both handled hot stuff, probably more than any of your people. Your man has checked us out on the pump a.s.sembly and we know just what we're looking for. Let's go."

Hall glared at the pair for a second and then whirled to the rigged tractor. "Get that canopy off that thing," he ordered. "They can ride it down in the seat."

He turned back to the junior engineers. "Got lights?" They both indicated a pair of sealed handbeams on their belts. "All right, get aboard."

"Casey," Hall called over the intercom, "got that communications line rigged?"

"All set, boss," came the answer. "It will run out the cable and down the cab. I've left them plenty of slack to move around when they get down there."

"O.K.," Hall waved to the riggers, "everybody get outta here. Casey, plug them in."

Alec and Troy had entered the cab. The communications man leaned over and coupled the phone system into their helmets and then waved at Hall.