(Recasts with deal reached to reopen government, changes dateline from Washington)
ATLANTA, Jan 22 (Reuters) - Thousands of federal employees breathed a sigh of relief on Monday after U.S. senators reached a deal to end a three-day government shutdown, turning their brief time away from work into what one scientist described as a "lunch break."
During shutdowns, nonessential government employees are furloughed, or placed on temporary unpaid leave. Those deemed essential, including those in public safety and national security, keep working.
Health scientist Tom Chapel, was among the large numbers of workers who spent the day at home, after being furloughed briefly from his job at the U.S. Centers for Disease Control and Prevention in Atlanta.
"It was essentially a lunch break," Chapel joked of the short amount of time he missed from work from the shutdown. "I'm a much more relaxed federal employee now that I have had a nice lunch break."
The federal government shutdown at midnight Friday amid a fight over immigration and border security between Democrats and President Donald Trump's Republican Party, the first time it has done so since closing for 16 days in October 2013, throwing 800,000 government workers temporarily out of work.
There was no official tally of how many were furloughed on Monday, the first workday during the government closure.
Senators on Monday reached a deal to keep the government funded through Feb. 8.
The move lifted worries of lost business in cities from Atlanta to Kittery, Maine, home to a large U.S. Navy facility that maintains warships.
"We're definitely having a slow day today," said Jay Patel, owner of the Fresh to Order restaurant directly across the street from the CDC's Atlanta headquarters, which towers over the low-slung buildings around it and plays a similarly dominant role in its neighborhood economy.
Traffic had been similar to what Patel expects on a federal holiday.
'JUST CONFUSING FOR PEOPLE'
Workers who had been furloughed expressed hope that they would not face a replay of Monday's unscheduled day off when Congress reaches its next self-imposed deadline in less than three weeks.
"I'm very happy that they have agreed to push that back to Feb. 8 so they can resolve whatever issues they can so we can get back to work and help the American people," said Duncan Giles, a customer service representative at an Internal Revenue Service office in Indianapolis.
Giles has worked at the IRS for 23 years, long enough that Monday's was the fourth shutdown he has endured.
"It's just confusing for people," Giles said. "If you were planning on doing a dinner out or going to an event or something like that, those types of things are going to have to be postponed until you know that you're going to be having those regular paychecks again."
At the Portsmouth Naval Shipyard in Kittery, Maine, some 5,300 civilian workers were told to show up on Monday, the third day of the shutdown, regardless of whether they had been scheduled to work that day, to learn if they would be furloughed.
Pentagon officials said more than half of the Defense Department's civilian workers would be furloughed. A spokeswoman for the Portsmouth Naval Yard did not immediately respond to a request for comment.
Environmental Protection Agency Administrator Scott Pruitt instructed all staff to work this week, telling employees in an email over the weekend that the agency has enough resources to remain open for a limited amount of time. (Additional reporting by Peter Szekely in New York, Valerie Volcovici and Idress Ali in Washington, Tom Jones in Lakewood, Washington and Chris Kenning in Chicago; Writing by Scott Malone; Editing by Jeffrey Benkoe and Lisa Shumaker)