Team members initially considered fabricating components in even larger assemblies at a shop further northeast, then shipping them across a greater expanse of water. Upon evaluating the additional engineering required, as well as the potential for disruptive lake conditions, planners subsequently reversed course, settling on Port of Indiana.

Supplemented with additional lighting, heating and outlets, the facility proved of sufficient height to accommodate the 60-ton hydraulic crane deployed to maneuver components, though adjustments to its entrance were required to facilitate ingress and egress.

As crews completed subassemblies, a self-propelled modular transporter—a remote-controlled assembly that Grooms likens to a 20-wheel semi-truck without the cab—transported them to the barge, where longshoremen utilized a 200-ton Manitowoc 4100 lattice-boom crawler crane to load them in place. Barges were met by another Manitowoc 4100 in Michigan City to unload components.

With the arrival of spring, Port of Indiana will commence shipment of ductwork to Michigan City, where sections will route boiler flue gas to scrubbers and baghouses for removal of sulfur dioxide, sulfur trioxide and other substances prior to routing it back to a chimney for release in the atmosphere.

Crews have not been completely idle as they await deliveries: About 280 workers were on site in late winter to complete construction of the baghouses and other assemblies shipped from Port of Indiana last summer and fall.

"We made 11 shipments from June to mid-November," Klaich says. Shipments were made in accordance with a "bottom-up" erection sequence and included virtually all scrubber and baghouse components.

"It's been akin to just-in-time delivery," says Grooms. "We're not stick-building over craftsmen's heads. That's where preassembly comes in."

Crews deployed a 600-ton Kobelco crawler crane to set circular cores, middles and tops weighing up to 70 tons within structural frames for reactor vessels, stacking one upon the other before crews proceeded with welds. Workers used the same crane to set baghouse modules within structural steel in early February.

Work is driving toward a delivery date of Sept. 4, when NIPSCO will suspend operations for 12 weeks to tie-in new components to existing ones, a period when crews will tear out ductwork feeding Unit 12's chimney and route new ductwork to scrubbers and baghouses and back.

"A lot of activities occur during a tie-in, and we're planning each in a very detailed manner," says Vacek. "This is going to be one very busy place."