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Hanford Site

The Hanford Site is 1,518 square kilometers (586 square miles) located in southeastern Washington. The Hanford Site was established during World War II as part of the Manhattan Project to provide the plutonium necessary for the development of nuclear weapons.

Currently, the Hanford Site is engaged in the world’s largest environmental cleanup with many challenges to be resolved in the face of overlapping, technical, political, regulatory, and cultural interests. The cleanup effort is focused on three outcomes: restoring the Columbia River corridor for other uses, transitioning the central plateau to long-term waste treatment and storage, and preparing for the future.

The Uranium Committee of the federal Office of Scientific Research and Development[?] (OSRD) decided to sponsor an intensive research project on plutonium, the strange new substance that had been isolated in a University of California Laboratory only nine months earlier. The OSRD placed the contract with the University of Chicago Metallurgical Laboratory[?] (Met Lab).

In the same month as the Battle of Midway, the Army Corps of Engineers formed the Manhattan Engineer District (MED) to construct industrial-size plants to manufacture the plutonium and uranium being investigated by Met Lab scientists. Six months later, just three days before Christmas 1942, as the nostalgic wartime song "White Christmas" was hitting Number One on the charts, Colonel Franklin T. Matthias[?] and two engineers from the DuPont Corporation[?] visited the future Hanford Site. On New Year's Eve 1942, they reported to General Leslie Groves, chief of the Manhattan Project, that the Hanford region was "ideal in virtually all respects" (Matthias 1987) in terms of the criteria defined for the plutonium production site.

In photos of early Hanford, we see serious-looking men with slicked-back hair and bulky clothes. We see squat-looking vehicles with huge rolling fenders and headlights that bulge forward like bug eyes. In our world of transistors and microchips and minivans, it is hard to imagine them building a place as macro as the Hanford Engineer Works (World War II name for Hanford Site).

Yet, they were real people, working under difficult conditions. They worked toward narrowly focused objectives, dictated by necessity, and they met every one of them. Evidence of their world-shaking accomplishments fills the Hanford Site - in the hulking, contaminated old buildings, and in the waste that workers endeavor to clean up. As they go about their job of finishing the production task, by cleaning up the old facilities and the waste, let us pause and recall the dire circumstances, the critical need, the harsh realities out of which the Hanford Site was born.

The eight oldest nuclear reactors (not counting N-Reactor) that stand as monoliths on the shoreline of the Hanford Reach contain stories that are among the richest in nuclear history in the world. Now silent, these reactors once hummed with the roar of water rushing through their process tubes and achieved the greatest throughput of special nuclear materials of any place known on earth. With an average individual life span of just 22 years, these eight reactors, which were known as "piles" during the 1940s and 1950s, were built between 1944 and 1955, and closed down between 1964 and 1971.

Tied in umbilical fashion to the Columbia River, the eight old reactors were known as "single-pass" facilities because their cooling systems drew water from the river, treated it chemically, pumped it through the process tubes to cool the uranium fuel charges, and then passed the water out to the river again for disposal. Between the reactors and the return trip to the river, the used cooling water (effluent) was held in large tanks known as 107 Retention Basins for periods that ranged from 30 minutes to 6 hours. This temporary retention provided for the decay of short-lived radionuclides picked up in the reactors. However, the longer-lived isotopes were not affected by this retention period, and thousands of curies entered the Columbia River every day, provoking, by the early 1960s, protests from the health departments of Oregon and Washington, as well as the U.S. Public Health Service.

At the World War II Hanford Site, the historic feat of starting up the first three, full-scale nuclear reactors in the world within a period of five months ushered in a 27-year period of hectic and remarkable pile development. The World War II reactors (B, D, and F) each were designed to operate at 250 megawatts (MW) of nuclear power. H-Pile, which started up in 1949, was designed to operate at 400 MW, and DR (D-Replacement), which started up in 1950, was a clone of D-Pile, designed to operate at 250 MW. C-Reactor, which was started up in 1952 with a nameplate design power level of 600 MW, soon became the chief developmental and production testing machine at the Hanford Site. Within three months of its startup, its primary function had been designated as that of prototype experimentation for the design of the "twin" K-Piles (KE and KW).

Completed in 1955, the KE and KW reactors were known as the "jumbos," because their nameplate design power levels stood at 1,800 MW, more than seven times larger than those of the World War II reactors. By the early 1960s, extensive modifications and upgrades had allowed the oldest five piles to achieve power levels ranging from 2,015 to 2,210 MW each, C-Reactor to attain 2,500 MW, and the K-Piles to reach 4,400 MW each. Thus, the scale-up achieved during the operating years was nearly as great as the historic leaps attained in World War II while building the original Hanford Site plants from laboratory-sized prototypes. And, along the way, some of the most important discoveries in physics and irradiation science were made.

The early operators of the Hanford Site's piles were puzzled and intrigued by many questions. For example, they knew that "slug failures," or the accidental penetration of a uranium fuel element's aluminum jacket (can) by cooling water, would cause the uranium to swell and block the coolant flow within the process tube and melt the slugs within that tube. No slug failures occurred at the World War II Hanford Site, but by December 1945, 125 slugs with mysterious "blisters" had been found by visual inspection in the irradiated fuel storage basins at the rear of the three reactors. Operators developed a pneumatic underwater lathe for opening up the warped slugs for further examination. For the next 7 years, blistered and ruptured fuel elements were opened and examined in steel tanks located in the 111-B Test Building. After the 327 Radiometallurgy Facility was ready, with its state- of-the-art hot cells, the 111-B Building continued to be used as an examination facility for sections of corroded and failed process tubes.

When fuel ruptures did occur, Hanford Site operators detected the problem with beta-sensitive water activity monitors located in the rear piping of the reactors. Higher radioactivity levels indicated a rupture, and the process tube containing the failure simply was emptied into the irradiated fuel storage basin. Sometimes, however, ruptures were severe enough that the failed elements stuck in the process tubes, and Hanford Site operators had to invent completely new techniques for removing the slugs and the tubes. They first flushed out the charges located downstream of the failed element (ie., in "back" of the problem slug in the process tube), and then removed the upstream charges using vacuum suction. They next employed a rotary reamer to bore out the tube ribs (internal projections used to guide and seat the fuel elements) downstream of the problem. The stuck charge then was pushed downstream with a hydraulic ram until it entered the de-ribbed area, where removal was completed with force from the pneumatic slug charging machine. Next, the damaged process tube was split internally with a special tube splitter developed at the Site, and then pulled out and chopped into short lengths with a unique Hanford Site instrument known as the "guillotine."

Another topic that intrigued the early operators of the Hanford Site's piles was that of temperature and flux distribution (flux is a measure of the number and speed of neutrons that are active at various nuclear power levels). During startups, flux levels changed rapidly as the control rods were withdrawn, and sometimes quirky and localized hot spots (areas of very high neutron activity) occurred. Such events could damage parts of the reactors, or cause automatic shutdowns triggered by safety instrumentation (known as instrument scrams). A distinct learning curve with regard to managing smooth startups separated junior and senior reactor operators.

Even after full operating power was achieved during the earliest years, a uniform poison (neutron absorbing) pattern was used throughout the reactors. This resulted in a flux distribution that achieved maximum irradiation only for the fuel charges located in the center of the piles, a situation that was inefficient in using the uranium fuel supply. Therefore, experimentation with varied poison patterns was undertaken, and, as with other operations, Hanford Site workers developed a colorful array of names for the different patterns: "dimpling," "bowing," and "thinning" the piles were among the flux distribution patterns of the late 1940s.

None of the early operating questions were more serious to Hanford Site scientists than that of graphite distortion. By early 1946, expansion of the graphite reactor cores, with subsequent bowing and binding of process tubes, had become so serious that B-Reactor was shut down to preserve it while graphite study went forward. The problem, as it turned out, was caused by the efficient heat-removal capacity of the helium in pile gas atmosphere. Higher temperatures were needed to activate and redistribute the carbon atoms in the graphite's crystal lattice. By the late 1940s, the addition of carbon dioxide, with its lower heat-transfer capacity, to the gas atmospheres of the Hanford piles annealed and aided the graphite expansion situation.

During the 25 years that followed the energizing of the first Hanford Site production reactor, many other puzzles were solved. In the constant search for operating efficiencies that would boost production, machines were developed that could charge and discharge a reactor while it was operating. Other new procedures cleansed film from reactor tubes during operation, and equipment known as "poison splines" allowed multiple modifications in flux and heat distribution as a reactor ran. New configurations and materials in fuel elements and process tubes allowed power levels nearly ten times those of the World War II era. However, while technical operating challenges progressed well in these historic reactors, waste disposal solutions remained elusive, and effluents continued to be released to the Columbia River.

http://www.hanford.gov



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