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,