The Schultzes were lucky in December when it was time to park their motorhome at River Town Campground on U.S. 61 South to begin a three-month business trip to Mississippi to join thousands working to refuel Grand Gulf Nuclear Station and bolster its output.

“We got one of the last four spaces here,” Donna Schultz said, as she prepared for a 12 1/2-hour shift in materials purchasing with her husband, Chris, a project-scheduling contractor, both with Florida-based Absolute Consulting. “And that was in December.”

They know others among the thousands of temporary workers at the plant haven’t been so fortunate.

“There’s a lot of people still looking for places,” she said.

A refueling shutdown expected to last about six weeks began last week, a prelude to myriad technical upgrades through the summer that will increase the plant’s generating capacity by 13 percent, making it the nation’s most powerful single reactor. Entergy has contracted 76 companies to provide up to about 4,000 workers to make it happen, with an additional 15 subcontractors on top of that, Entergy Nuclear spokeswoman Suzanne Anderson said. Ordinarily, the plant employs about 700 people, many of whom live in Vicksburg and Warren County.

As expected, the project has hotel bookings on the rise and phones at apartments and campgrounds ringing steadily.

Local hotels and motels showed a 54.4 percent occupancy rate, up more than 11 percentage points from December and up nearly 12 points from January 2011, according to Smith Travel Research Inc., a Nashville-based hotel industry tracker. Seventeen of the city’s 32 hotels reported figures to subscriber service, the same reporting total as December when the rate was 43.2 percent.