Registration for this year's public tours of Hanford starts at 12:01 a.m. Tuesday.
Last year, 1,000 seats were claimed in 15 minutes and all seats were reserved before noon.
Registration for the popular tours of the closed nuclear reservation only can be made online. Go to www.hanford.gov and look for "Hanford Tours" under the quick links.
The bus tours take about five hours and include a walking tour inside Hanford's historic B Reactor.
Never miss a local story.
Participants get a look at environmental cleanup of the site needed because of wastes left by the past production of plutonium for the nation's nuclear weapons program.
Tours are scheduled for 8 a.m. and 10 a.m. April 12, 13, 14 and 27; May 10, 11, 12, 24, 25 and 26; June 7, 8, 9, 21, 22 and 23; July 19, 20 and 21; Aug. 2, 3, 4, 16, 17, 30 and 31; and Sept. 1, 20, 21 and 22.
There are seats for about 2,540 people.
Any seats that open because of cancellations will be posted online without notice. Participants must be at least 18 and U.S. citizens.
Registration for tours of just the B Reactor will begin March 15.