Many seats remained available for free tours of Hanford's historic B Reactor by Tuesday afternoon, the first day of registration for the tours.

About half of the 2,750 seats available through online registration still were available by late afternoon, although weekend tour seats had been claimed. Tour registration is available at ow.ly/9KkHX.

Registration also is being accepted for about 770 seats at the B Reactor tour office, which is open 8 a.m. to 4 p.m. Mondays through Thursdays and may be reached by calling 376-1647. The address is 2000 Logston Blvd., Richland.

The telephone rang nonstop all day Tuesday, but some seats set aside for telephone registration remain open, said Geoff Tyree, a Department of Energy spokesman. That telephone number also can be used to arrange group tours and school tours.

Four schools have signed up for tours so far this year, the first year children ages 12 and older have been allowed in the reactor. The first tour will be Thursday for students at Delta High School in Richland.