Almost half a century ago, President John F. Kennedy stood before a crowd of 37,000 people at Hanford's N Reactor to dedicate the reactor and preside over the ground-breaking for a steam turbine plant that would generate electricity.
N Reactor, the newest and longest-running of the nine production reactors at the Hanford nuclear reservation, would produce plutonium for the nation's nuclear weapons program and enough electricity at its peak for about 650,000 homes.
Thursday, a much smaller crowd of about 100 invited guests and workers gathered near the same spot to mark the end of the reactor.
Washington Closure Hanford has finished most of the work to cocoon the reactor, putting it in storage until the radiation in its core can decay for 75 years to more manageable levels.
David Huizenga, the Department of Energy senior adviser for environmental management, repeated Kennedy's words of Sept. 26, 1963, just two months before the president's assassination.
"Along this river, men have played a significant role in the last 20 years, which has changed the entire history of the world," Kennedy told the crowd, and spoke of "the role the men and women who worked here have played in the years since the second world war in maintaining the strength of the United States."
The current workers of the Hanford nuclear reservation are carrying on that legacy, Huizenga said.
During the past three years, Hanford workers have torn down six large, attached concrete buildings and sealed up what remained -- the reactor core and the attached heat exchanger building needed for producing electricity.
They took the guard station off the roof and reroofed the remaining structures. On Thursday, some final work was being done to seal up any openings that animals might be able to enter, before the door is closed and locked on the reactor.
In addition, 92 other structures near N Reactor have been torn down.
Huizenga had mixed emotions as he stood before the almost cocooned structure, after visiting the reactor while it operated, he said.
So did the former workers invited to the reactor site Thursday.
Over its lifetime, N Reactor generated more the 65 billion kilowatt- hours of electricity, said Emil Leitz, who was the startup engineer for the plant. He was there from before it began operating in 1963 until it was shut down in 1987.
It was not the 1986 Chernobyl nuclear disaster that led to the decision to shut down the reactor, said former Hanford DOE manager Mike Lawrence. The reactor had superficial similarities to Chernobyl and operations stopped while unrelated safety upgrades were made.
A year later, the energy secretary decided the nation no longer needed the plutonium it produced.
N Reactor could not have the same type of runaway reaction, because if its graphite heated up, the reactor was designed to automatically shut down, Leitz said. The Chernobyl reactor was designed to power up as the temperature in the graphite increased until the control rods could not shut it down, he said.
Leitz was there the day President Kennedy visited, and he remembers a big cloud of dust when his helicopter landed at what then was a construction site, a short speech and then a big cloud of dust when the helicopter left.
Leitz is particularly proud that N Reactor opened the door for the first certified reactor operators at Hanford. Its first two women operators, Leslie Jensen and Martha Koop, were there Thursday.
"I loved it," Jensen said, who had been a school teacher. "It was my favorite job of all time. When it shut down, it broke my heart."
She remembers one man was skeptical that women could operate the reactor, but became helpful when he realized how serious she was about the job.
Jensen liked the job because of the continual challenge of learning -- once a year a demonstration and oral test were required -- and the job's great responsibility.
She sat in the operating room and pulled the rods that controlled the nuclear reaction for part of her shifts.
N Reactor was different from the other Hanford plutonium-production reactors, not only because it was the nation's only one with a dual electricity-production and defense purpose, but also because of a design more protective of the environment.
It was Hanford's only reactor that recirculated cooling water rather than using it once and then returning contaminated water to the Columbia River.
It is the sixth reactor to be cocooned at Hanford. The K East and K West Reactors also will be cocooned, but the remaining reactor, B Reactor, is being preserved as a museum.
Because of the reactor's dual mission, it's been the largest and most difficult cocooning project to date, said Matt McCormick, manager of the DOE Richland Operations Office.
It's also the reactor closest to the river, making cocooning of the reactor and removal of many highly contaminated buildings, "another tremendous step toward protecting the Columbia River," said Carol Johnson, president of Washington Closure.