When America was struggling to develop what was then called the atom bomb, before the Germans or Japanese could do so, locations were required which had a rather unique combination of features. All had to be large, open, have access to large amounts of electricity, be sparsely populated, and be isolated enough to be kept secret, and to shield the public from any possible dangers. Few such places existed then, or now. Generally, ample electricity is associated with population centers. Oak Ridge was begun first and was initially planned as the site of the entire operation. Soon enough, though, it became plain that the development of the atom bomb was to be a much larger project than had originally been envisioned.

        The use of uranium was initially thought to be key, as a nuclear explosive; but it was recognized that only a massive industrial effort would be able to separate the required isotope, from the large amounts of natural uranium being refined. The largest building in the world was built at Oak Ridge, to do the separating. The K-25 separation building, at Oak Ridge, was a half mile long, by a quarter mile wide, and took over 2 years for 20,000 construction workers to complete. On top of all of this, it took huge amounts of power, and considerable time to separate the required isotope. There had to be a better way. Despite all of the time, effort, and money invested, K-25 did not produce any appreciable amounts of nuclear explosive in time for WWII - a better way had been found.

        The better way turned out to be a sort of a nuclear shortcut, in the form of the then mysterious element 94. Element 94 does not exist in nature, at least not here on Earth (actually, recent discoveries have turned up minute amounts of certain isotopes; but only in microscopic quantities), and had never been seen by man, before small quantities were produced as a byproduct of certain nuclear reactions. These small quantities of this new element showing up, opened new potentials, and a possible different approach. Scientists calculated that a common isotope of this new element would make a great nuclear explosive, better in some ways than the difficult to separate uranium 235 isotope. It also seemed that, once proper facilities were put in place, it could be produced and purified more quickly than the uranium isotope, because it could be separated by relatively simple chemical means, rather than the painstaking and energy intensive weight separation employed in obtaining uranium 235. The new substance would be named plutonium.

        The air cooled X-10 reactor was built at Oak Ridge, specifically to see if this new substance could be produced more quickly, and in quantity. The idea proved both viable and practical; but a larger reactor was required. The X-10 (in diagram to the right) was a 24 foot block of graphite, which produced around 1000kw, using 1248 loading tubes. The rule of thumb about plutonium production is 1 gram per MW, per day, so the X-10 produced a gram of plutonium a day. This was a good demonstration of the plausibility of the concept, and would be the blueprint followed in future production reactors; but it was not nearly enough. At such a rate of production, it would take 16 - 18 years, to make enough for a bomb. Something bigger was needed, by a whole magnitude of order, and that was the problem.

        The Manhattan Project was getting quite a bit bigger than anyone had expected, which was a particular problem with the level of secrecy being sought. The war time population of Oak Ridge was about 70,000 people. There was the X-10 facility, the calutrons at Y-12, and the huge K-25 separation plant, as well as the city itself, associated labs, and support facilities. The new plutonium based approach would require an effort equal to that already in place for creating a uranium based bomb. Oak Ridge was getting too crowded to base such an effort here. A new site would have to be found.

        One of the locations scouted turned out to be ideal. There were few residents, it was miles from any major population center, it was desolate and almost unpopulated. The nearby dams produced abundant electrical power, and as a bonus the rivers which fed the dams offered a generous supply of cooling water for the proposed reactors. It was perfect. Located in south eastern Washington state, it was far enough from the coast, that there was little worry about Japanese attack. The residents were moved out, being given thrity days notice, and the military and scientific teams were moved in.

        The new reactor, known as the B Reactor, was to be water cooled, rather than relying on the less capable air cooling of X-10. This, along with its increased size, would permit much more power, and thus much more plutonium production. The initial power level attained was 250 times that of the old X-10 reactor. At this level of production, it would take months, rather than years, to produce enough plutonium to complete a bomb. A year would be enough time to produce plutonium for use in ten bombs, though in reality the Manhattan project only produced four bombs, two of which were dropped on Japan, and one of which was set of in the Trinity test.

        The reactor was not built here in isolation. Two other reactors, the D and F, were built before the war ended. With B, F, and D reactors built during the war, and C to be built latter, the question has been raised about the A reactor, and apparently there was none.  (Perhaps X-10 was considered to be the A reactor. Who knows? I have never heard anyone think to ask what ever happened to reactors X-1 through X-9.) There was also far more to the site than the eventual nine reactors.

        Still, the reactors were only the beginning of the process and of the project. Plants were needed to produce the nuclear fuel, and purify the end product. It was also planned that there would be more than one reactor here, as the site was such an ideal location. There would need to be waste disposal sites, and laboratories. The further along the project went, the more obvious it became that this would not have fit at Oak Ridge, with the facilities that were already there. During the war, 48,000 people lived and worked at what had originally been a desolate stretch of ranchland and desert. The Hanford site has a list full of interesting facts, that show just how impossible it would have been to crowd these facilities in with those already at oak Ridge. As an example of the logistics, they say that 6500 eggs were used in a typical Sunday breakfast, along with 5000 pounds of sausage - 120 tons of potatoes were eaten each day, along with 30,000 doughnuts, and  8000 pounds of coffee.

        The one and only reason for all of this effort was the production of plutonium. After WWII was won, the United States pursued development of nuclear weapons, as a necessary part of having become the new world power. When the Cold War started soon afterwards, with America and the Soviet Union becoming the super powers, there was even more reason to step up plutonium production, in order for America to continue to be the new world power. Eventually, nine reactors would be working here, to produce over two thirds of the nation's stock of plutonium. B reactor was shut down in February of 1968, with the similar single pass reactors all shut down by 1971. The N reactor, which was a multi pass reactor, remained open until 1987. The N reactor was the only Hanford reactor used to produce electricity.

        A single pass reactor uses cooling water only once. In the case of Hanford, the water was taken from the river, cycled through the reactor, and then discharged into a settling pond, before being emptied back into the river. A multi pass reactor uses the same water over and over again, in a closed system. Unfortunately, single pass reactors can pollute a river, particularly when water is not held for sufficient amounts of time in the settling ponds, which can often occur when there is demand for increased production.. The multi pass reactor has no such issues.

        The main components of the site, besides the nine reactors, were the chemical separation plants, called canyons. The first was nicknamed Queen Mary, because of its huge size, and the way it appeared on the desert horizon, like a ship on the ocean - complete with stacks. These were located in the 200 areas shown on the map above, while the reactors were along the river in the 100 areas, about 10 miles away. These were connected by a rail line. There were also five reprocessing plants, and a finishing plant, which was able to convert the results of the separation plants into pure plutonium metal. There were also plants for fuel production.

Hanford Today

        Today, much of the old Hanford is gone, and production of plutonium here has ended. This does not mean that the site is inactive - quite the contrary. A huge, two billion dollar a year clean up is going on, and will continue for the next thirty years or so. If the economy is bad in your area, and you are looking for a new start, there is quite a bit of opportunity here. If I were a younger man, I might just consider migrating here myself. Men and women will make entire lifetime careers doing this important work, One major aspect of this clean up is the sealing (called cocooning) of the old production reactors. These are in the 200 square mile river corridor area, also known as the 100 area. A cocooned plant is partially dismantled (up to the shield wall), welded shut, sealed with concrete, and capped. Every ten years or so, the welds are broken, and survey teams go in, to measure residual contamination. The photo to the left shows the cocooned C reactor, next to the B reactor that I visited. This was to be the fate of the B Reactor, and would have been, were it not for the efforts of various preservation groups.

        There were other facilities here, including fuel fabrication plants, which will need clean up, and have largely been demolished; but the reactors are the main concern. According to DOE, the river corridor contains 761 sites, where clean up is required. This includes the reactors, the fabrication plants, landfills, waste storage tanks, cooling ponds, and the residue from leaks and spills. During The Cold War, such things were a concern, but a secondary concern, when compared to winning a possible nuclear war with the Soviets. Today they are the primary concern. Ironically, places like Hanford saved us from the nuclear threat posed by the Soviets, and other enemies. Today, clean up efforts seek to save us from the nuclear threat posed by these very saviors.

        Most of this waste, particularly contaminated soil and low level waste, will be relocated to the Environmental Restoration Disposal facility (ERDF), within the Hanford Site itself. This is on the central plateau of Hanford. ERDF has a capacity of 10 million tons of material. Once filled, it will be capped, and barriers will be put in place to prevent leakage. The radioactive contamination will then be allowed to decay, safely contained. The ERDF was one of the stops on the site tour, and the place is absolutely huge. Our guide boasted that the great trench can be seen from space, with the naked eye. As we watched, a stream of trucks shuttled materials down into the trench, to be moved into position by bulldozers, and other heavy machinery. And so it will go, for decades before completion. The river area could be cleaned up within the next 5 - 10 years, and possibly be opened to the public and integrated within the Hanford Reach preserve. Still, not everything has been cleaned up, and not all sensitive research has been stopped. Many of the areas of the site are still under heavy security, and will continue to be so during the foreseeable future.

        Also stored at the site, are 2100 tons of spent fuel which was awaiting processing when production was shut down, as well as another two tons of spent fuel from commercial reactors, and another 140 tons of uranium which was to become fuel. Nine hundred tons of uranium have been removed from the site, presumably to Yucca Mountain or some such place. One of the most interesting things that I saw (but sadly was unable to photograph), was a trench containing discarded reactors from decommissioned nuclear submarines and surface ships. There were dozens of them in a long trench - perhaps a hundred or more. Most are brought here from the Bremerton shipyards at Seattle. They appeared as sections of huge metal cylinders.

        At the other end of the site, in the 300 area (see map above), most of the older buildings have been demolished. This was largely where fuel was fabricated, and most of the buildings were too contaminated to be saved. There are still radiological labs here, and much research is being done. Some new facilities have been constructed, and the Pacific Northwest National laboratory is still actively doing research.

        Nearby is the Ariva plant, where commercial nuclear fuel is still being made. This is a pretty secure place; but it is good to know that there is still something of a commercial nuclear infrastructure in this country.

        Energy Northwest does have one power reactor here. This is the only active reactor currently at the site. Another reactor, a smaller unit known as the Fast Flux Test Facility, was also in place; but sadly was decommissioned and is being dismantled. This was a sodium cooled reactor, which used fast neutrons, and was a test bed for new technologies.

Plutonium Production

            At its original output, the B Reactor could produce 250 grams of plutonium a day – about ten ounces. Eventually, the B reactor would produce eight times this amount, with some other reactors making over twice as much. This sounds far simpler and more straightforward than it really was, as if you might just find bits of plutonium laying at the bottom of the rector; but there were a couple of complications. At its peak, in the sixties, Hanford probably produced enough plutonium for 30 – 35 nuclear warheads, every week.

            The only way to get that plutonium was to shut the reactor down, and push the fuel out into the collection area. The fuel would then be allowed to cool, after which it would be collected for processing. So, how often do you do this? Well, that was the big question.

            Recall that the B Reactor holds 200 tons of fuel, out of which around ten ounces a day is eventually transmuted into plutonium. 200 tons comes out to 6400000 ounces. If you do the math, it turns out that it would take 1753 years, for the whole mass to be converted. Even at it’s maximum output of over 2GW, it would still take close to 500 years to convert the whole mass. We didn’t have that much time – there was a war on. Even if we did have the time, there is another factor.

            Just for argument’s sake, lets say that you did have 500 years to wait around for all of your uranium to transmute into plutonium. So you leave those rods in the reactor for 500 years, and then have your descendants push them out. Would you have 200 tons of fully converted plutonium 239? Certainly not! What you would have, would be a mess - an incredibly dangerous, and useless, mixture of highly radioactive transuranic elements, and radioactive isotopes. Even the proportion of plutonium included in the mixture would no longer be pure Plutonium 239; but would be of several different isotopes, and would be useless without the same sort of separation which presently makes U235 such a difficult material to procure. The reason for this is simple.

            Inside of a nuclear reactor, elements are being constantly transmuted. This includes the element of plutonium. Plutonium is not produced directly. What happens is that the uranium 238 is converted to Uranium 239, which quickly decays to Neptunium 239, and then to Plutonium 239 – the desired end product. Unfortunately, all of these elements are subject to further transmutation, as long as they remain in the reactor.

        So at any given time, you would have a mixture of uranium 238 – the original fuel – along with some uranium 239, neptunium 239, and plutonium 239. You would also have various isotopes of iodine, krypton, xenon, and americunium, as well as unwanted isotopes of plutonium. These elements have different half lives, which is to say, they transmute at different rates. They also have different capture cross sections, which is to say they are not all affected by the neutron bombardment, which occurs inside of a reactor, at the same rate. The proportion of these elements thus changes over time. This variety of elements is the flip side of the nuclear shortcut which allows plutonium to be produced to supplant uranium as a nuclear explosive.

        Though we humans see uranium 238 as fuel, and plutonium 239 as the end product, nature has no such bias. Plutonium 239 which remains in a reactor, continues to fission or capture under neutron bombardment, and can contribute as much as a third of the energy to the output of a reactor. In a power reactor, this is great news, and led to the idea of the breeder reactor. In a production reactor, it is a terrible nuisance. You don’t go through all of the trouble to produce this plutonium, just to have it burn up inside of the reactor, or become contaminated with unwanted isotopes. So you have to get it out; but at what point?

            Well, I can’t really answer that question. It appears to be a matter of a few weeks at most; but I am unable to find a definite answer anywhere on the web, or in any of the books on the subject. I may have just not researched thoroughly enough, or the information may simply not be available. The subject may still be classified, as it would seem to be a useful bit of information to potential nuclear states. There is, presumably, a point at which the amounts of useful materials (uranium 239, neptunium 239, and plutonium 239) being produced approaches the law of diminishing returns, where as much (or more) is being burned up as is being produced. It may be that, even before this point is reached, you may wish to eject the fuel, in order to save your fuel stock. There is also a concern about producing undesirable isotopes of plutonium, which could not be easily removed.

         According to the World Nuclear Association ( http://www.world-nuclear.org/info/inf15.html ) 

"It takes about 10 kilograms of nearly pure Pu-239 to make a bomb. Producing this requires 30 megawatt-years of reactor operation, with frequent fuel changes and reprocessing of the 'hot' fuel. Hence 'weapons-grade' plutonium is made in special production reactors by burning natural uranium fuel to the extent of only about 100 MWd/t (effectively three months), instead of the 45,000 MWd/t typical of LWR power reactors. Allowing the fuel to stay longer in the reactor increases the concentration of the higher isotopes of plutonium, in particular the Pu-240 isotope. For weapons use, Pu-240 is considered a serious contaminant, due to higher neutron emission and higher heat production. It is not feasible to separate Pu-240 from Pu-239. An explosive device could be made from plutonium extracted from low burn-up reactor fuel (i.e. if the fuel had only been used for a short time), but any significant proportions of Pu-240 in it would make it hazardous to the bomb makers, as well as probably unreliable and unpredictable. Typical 'reactor-grade' plutonium recovered from reprocessing used power reactor fuel has about one third non-fissile isotopes (mainly Pu-240)."

            One of our guides had worked as a reactor operator, and he advised us that refueling the reactor occurred at an intervals of a few days, to a few weeks, which differs a bit from what the World Nuclear Association says. He also advised that it was not necessarily done en mass. The fuel in the center portions of the reactor, where the radiation was more intense, and the reactions more vigorous, was cycled more often than that at the edges. I tend to place more credence in the words of the reactor operator, mainly due to his first hand experience. The World Nuclear association is more about nuclear power, than nuclear weapons. Using this as a guide, just to get an idea of what is involved; let’s create the following vastly simplified (and possibly numerically incorrect) scenario:

            After two weeks (14 days) the reactor is stopped, and the fuel ejected for processing. It sits in a water filled receptacle at the back of the reactor for a few days. This permits it to cool, and also allows the existing Uranium 239, and Neptunium 239 to transmute into Plutonium. Let’s assume the B reactor's maximum power of 2GW, which was about eight times its initial operating power. So it would have produced, assuming no losses to further transmutation, 1120 ounces of plutonium, or about 70 pounds – out of 200 tons of material. The actual amount would be less due to further transmutation by continued nuclear reactions. The longer the material is left in the reactor, the greater these losses would be.

            A crane operator removes the rods, and places them in buckets for transit to the processing plants, about ten miles away, by a rail line built for this purpose. So once you have the rods out of the reactor, and have dissolved them, a series of chemical steps separates the plutonium, which differs chemically from the original uranium feedstock. What you end up with is about 70 pounds of plutonium (enough for maybe five nuclear warheads), and around 200 tons of left over uranium dissolved in hundreds, or thousands of gallons of solvents and other noxious chemicals. These tended to be stored in gigantic tanks; but even this was not the end.

            Uranium is a strategic material, and even though un-enriched uranium is not particularly valuable, it is not something you simply want to throw away. It is also not something that you want to leave just laying around. So, various methods of reclaiming the dissolved uranium were developed. Some worked better than others. All required some pretty serious, and dangerous, chemistry. Reclaiming the uranium, still left the chemicals from which it had been separated, as well as the additional chemical residue from the process of reclamation. More storage tanks were built. And on it went, though much of The Cold War.

            So this is the legacy that we are now cleaning up. There is everything from hexane and chromium, through leaky tanks of plutonium slurry, to barrels of oil with shavings and scraps of uranium. Thrown in the mix are partially processed spent fuel rods, and partially finished new fuel rods. Often, when excavating an old land fill, the workers have no idea what they will find buried, making this a very slow, careful, and painstaking process.

Reactors at Hanford

Some photos of the Site

I am only guessing at what some of these are. if you happen to have worked at Hanford, or just happen to know what some of these places are, I would appreciate hearing from you. I felt a bit like an old time Soviet spy, grabbing these photos from the bus window, as we skirted the site. No doubt, large numbers of photos were taken by actual Soviet spies during the Cold War.

	Above: Hanford as it probably looked for thousands of years, before being taken over the the government. Left: An old homestead, probably a ranch, from the area's early days of settlement. Below: A view of the Columbia River, from the road outside the site. Reactors are visible along the river.
	An old guard shack, as well as an iron bridge, harken back to WWII.
	This is the B Reactor, and the cocooned C reactor, as they appear from the road outside of the site.
	Left: These are the twin D and DR reactors, built during the war, as seen from the site of the B Reactor. Below: the raised silo are at the end of the building identifies this as the REDOX building. This was one of several chemical separation canyons.
	A look at the end of the REDOX building.
	A T plant, as seen from the nearby highway.
	This appears to be the PFP complex, as seen from the nearby highway.