Hanford Site: Manhattan Project B Reactor Tour

Hanford – for those who know what and where that is – was shrouded in secrecy for decades. It is the site near the city of Richland in Washington state, that met nearly every criteria the United States government had in 1943 for establishing a nuclear production complex as part of the Manhattan Project, first to create plutonium from uranium that went into the atomic bomb Fat Man dropped on Nagasaki, Japan, and after that fueling the nuclear arms race during the Cold War.

I went on two of the three free and public tours of Hanford: the Department of Energy (DOE) Hanford clean up tour which is one of the world’s largest environmental clean up efforts and a more difficult tour to get on because of limited dates and seating; and the Manhattan Project B Reactor Tour, hosted by the National Park Service (NPS), that runs nearly daily.  While the DOE tour is more restrictive, the NPS tour is open to anyone, and cameras and recording devices are allowed. The B Reactor tour is confined to essentially the inside sections of the reactor that have been opened up to the public, but one can roam freely through the open corridors at one’s own pace, and there are a few presentations by docents. For someone who likes seeing the technology and engineering, this access was an especial treat.

B Reactor was the first nuclear reactor built as part of the Manhattan Project, and the first large scale reactor in the world. After the NPS bus drops you off at the doorstep of the reactor, you enter a hallway and soon step out into a huge room: the impressive front face of the reactor.  It is massive. Very quickly you get a sense of the enormity and precision required, both of the science, and in building the thing.  They show you a model of the reactor, the many layers around the core as shielding to protect against radiation outside of the reactor. The reactor sits on 28 feet of concrete, and has 2004 process tubes. These tubes extend within 72,000 hand drilled graphite blocks (graphite to slow down neutrons), that were placed by bricklayers and had to be exactly precise so that the 40 foot process tubes could be threaded through. There are no guides, and it is gravity that holds the blocks against one another. Eventually the fuel rods of uranium, about the size and length of a track baton, were slid in, through the front face side, initially by hand and ram rod (multiply that by 2004), and later pneumatic machines were made to load the process tubes. Each ton of uranium that went into B Reactor yielded only half a pound of plutonium. The center of the reactor was the hottest, and could “cook” the fuel rods in 30-60 days; but in the outer cooler area, it could take six months. And “hot” as in the water from the Columbia River would be pumped in at a rate of thrusting through the reactor in one second, and within that one second, go from 55 degrees Fahrenheit (13C) to 190 degrees Fahrenheit (88C). Once deemed done, some rods were discharged out the back side of the reactor into a pool of to keep them cool, while others stayed in the reactor to continue the reaction process, and new rods were added from the front. That, then, is the reactor core. The layer right beyond the graphite block core was thermal shielding of cast iron, blocking about 90 percent of the radiation. The outermost layers took care of the remaining 10 percent of the radiation, through alternating biological shielding of steel and masonite (essentially clipboard material).

At some point the fuel rods were packed in this room,

and sent by train to the processing facility that was next in the uranium-to-plutonium production process.  Mock fuel rods are displayed in the crates in the room, for visitors to get an idea of how they looked and their size.

The large valve pit room is also open. Treated water came through these many pipes, and flushed through the reactor process tubes to cool the reactor. The covers of the piping remain open, as proof to for the annual Russian inspection that the American government is fulfilling the treaty and not producing nuclear weapons at the site – though so many reactor support buildings have been demolished, the reactor is clearly defunct even without the pipe covers off.

A close second if not equal delight of the B Reactor front face is the control room. All of the instruments monitoring each aspect of the reaction process, the cooling, the back-up interventions should power shut down or there be a breach; the hundreds, thousands of buttons and connectors – is just awesome to see.


Other artifacts are on display throughout the open areas of the reactor: an exposure rate slide rule, since back in the day there weren’t the little devices for people to wear that automatically calculated for a person how much radiation they were being exposed to;  protective clothing layers required (though clothing itself would not protect against the radiation); signs from across the site; an old filing cabinet with a nod to both the US government and contractor DuPont in its labels.

If you are someone who likes to see and walk through and see first hand the actual material objects and scale of the inventions that had such a significant impact on world history – you will not at all be disappointed by going on the Hanford Manhattan Project B Reactor tour. If you are curious about the after effects – the contamination and the clean up – you can see my write up on the DOE Hanford clean up tour at this link.