Hanford plant

A description of how the Hanford plant discards hot equipment, was published in the May, 1955 issue of Nucleonics. The techniques involved are as follows ... 

The Manhattan Project marked scientists and engineers who participated in it for the remainder of their working lives. The designers and operators of the Hanford plant confronted threats to air and water of an unprecedented nature and scale. The job of containing those threats fell to DuPont s environmental specialists. Like others in the bomb project, they would not be the same when they emerged from the experience. 

U.S. plants. The principal U.S. reprocessing plants are listed in Table 10.3, together with their main process features. All use some form of the Purex process. In 1979, the only ones operating were the Savannah River and Idaho plants of the U.S. Department of Energy (DOE). The Hanford plant had been used primarily for recovery of plutonium and uranium from irradiated natural uranium, but was versatile and had been used, for example, for Thorex... 

Analyses of mortality among persons chronically exposed to plutonium in the workplace have been conducted. In the three occupational cohorts studied (Los Alamos Laboratory, Rocky Flats facility, and Hanford Plant), there were consistently fewer deaths than expected based on data for United States white males (Gilbert and Marks 1979 Voelz et al. 1983a, 1983b Wilkinson et al. 1987). This phenomenon is generally attributed to the "healthy worker effect," which holds that individuals in the work force are healthier than those in the general population. However, in a refined cohort from the Rocky Flats facility, the mortality of plutonium-exposed workers was compared to that of unexposed workers from the same plant. It was reported that death from all causes was elevated in exposed individuals but the increase was not statistically significant (Wilkinson et al. 1987). 

But Fermi s reactor just demonstrated the principle. To produce the amount of plutonium needed for a bomb, the Hanford plant was built in the state of Washington. The scale and speed of the project were such that the contract was signed for Hanford before the Fermi reactor actually ran. For the Hanford plant Seaborg and coworkers had to devise separation schemes for kilogram quantities of plutonium... 

At the Hanford plant, a variety of irradiated fuel elements require safe storage prior to reprocessing. Arrays of such subcritical units may be safely stored in water if a water gap between units, s ifficient to inhibit excess neutron interaction, is provided. The size of the gap is limited by the composition of the unit, the k-effec-tive of the unit and the maximum k-effective permitted for the array. In the past, a computer calculation has often been necessary to determine array safety but a simple relationship for determining safe unit spacing for less than complete isolation has been developed which can be used in many studies and which can reduce computer calculation. 

The decrease in critical mass caused by poorly absorbing neutron scatterers has been shown before. These materials tend to decrease the critical mass because they scatter neutrons isotropically, thus tending to hold them within the system. The solid of the Hanford plant contain a number of these materials (oxygen, Silicon, aluminum, etc.). Calculations show that if plutonium is dispersed within the soil, the soil components cannot be Ignored. 

No damaging earthquake has ever been received in the lomedlate vicinity of the Hanford Plant However, earthquakes causing moderate to severe damage have occurred in the Pacific Northwest Moreover, earthquake damage could result in a severe accident if suitable resistance were not provided Therefore, prudence required that the critical systems in the N Reactor complex be built to withstand severe earthquake shocks ... 

Use of O.9U7 w/o U, enriched uranium will not be new to the Hanford plant. Fuel of this enrichment level Is presently used In amounts not exceeding ten per cent of the total plant throughput for pile flattening purposes and reactivity compensation. 

What might cause a "major disaster" on a Hanford plant ... 

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