Nuclear waste isn't all that's hot at Hanford.

So are tickets to tour the closed nuclear reservation.

In 13 hours and 9 minutes all 2,544 seats for Hanford public tours this year from April through September had been claimed.

Registration for the free tours opened at 12:01 a.m. Tuesday and 500 seats were reserved in the first minute. By 12:31 a.m. 1,000 seats were taken.

The last registration for the tours was accepted at 1:10 p.m.

All registration was done on the internet and Hanford officials know that people from 41 states and 287 U.S. cities visited the tour sign-up page.

If you didn't get a seat on the bus, you're not out of luck for the year. When cancellations are received, openings are reposted without notice at www.hanford.gov.

The tours, which leave from Richland, last more than five hours and give visitors an idea of the size of the 586-square-mile nuclear reservation and the scope of environmental cleanup of contamination and waste left from the past production of plutonium for the nation's nuclear weapons program.

Visitors also get a look inside Hanford's historic B Reactor, the nation's first full-scale production reactor. It made the plutonium for the nation's first nuclear explosion and the atomic bomb dropped on Nagasaki, Japan, helping to end World War II.

Seats on the 2010 Hanford tours took about 1 hour and 40 minutes longer to fill than the seats on the 2009 tours. But this year there are more opportunities to see B Reactor than last year.

At 12:01 a.m. Tuesdaya fresh round of registration opens for those who want to visit just B Reactor rather than the entire Hanford site. The B Reactor tours include two hours at the reactor and a 45-minute bus ride each way from Richland.

This year B Reactor tours will be offered on 36 weekdays and Saturdays from April 6 to Sept. 25. Saturday bus tours will start at 8 a.m. and 12:15 p.m. and weekday minibus tours will start at 9 a.m.

Internet registration also is done at www.hanford.gov. But to help those who don't use the internet, 10 seats on each weekday tour will be reserved for those who register by telephone or in person at the B Reactor tour headquarters.

Phone and in-person registration also starts Tuesday and may be done when the tour headquarters are open 8 a.m. to 4 p.m. Mondays through Thursdays. Call 373-2774. In addition, there typically are one or two cancellations or no-shows, leaving empty seats on the days of the tour. Those will be available to walk-ins.

Visitors to B Reactor must be at least 18, but are not required to be U.S. citizens.