Hanford reactors

Irradiated Fuel A historically important and continuing mission at the Hanford site is to chemically process irradiated reactor fuel to recover and purify weapons-grade plutonium. Over the last 40 years, or so, several processes and plants— Bismuth Phosphate, REDOX, and PUREX—have been operated to accomplish this mission. Presently, only the Hanford PUREX Plant is operational, and although it has not been operated since the fall of 1972, it is scheduled to start up in the early 1980 s to process stored and currently produced Hanford -Reactor fuel. Of nine plutonium-production reactors built at the Hanford site, only the N-Reactor is still operating. 

Radiocerium can also gain entry into food crops through irrigation or flooding of fields with waters containing these nuclides. However, only small amounts of radiocerium enter food crops by this route compared to the more soluble radioelements that have been studied. Cerium-144 originating from both the Hanford reactors and worldwide... 

As previously mentioned, aluminum oxide is used as our primary collector, but other media have been used for special situations. For example, when the Hanford reactors were operating, quantities of hexa-valent Cr were discharged to the Columbia River and subsequently to the ocean, and we were interested in studying the dispersion rate of the Columbia River plume. Alumina did not collect the dichromate ion eflBciently. By using alumina saturated with stannous chloride, the chromium was reduced oa contact to the trivalent state, and this was very eflBciently retained on the bed. We also found that by saturating alumina with barium sulfate, we could collect radium isotopes, presumably by a replacement reaction with the barium on the matrix. For... 

Jackson and Walser [Jl] have given a detailed description of the operations conducted in 1970 by the Atlantic Richfield Hanford Company to separate and decontaminate and its associated thorium from aluminum-clad thorium dioxide irradiated to low burnup in the Hanford reactors. 

It is important to note that iodine deficiency and exposure to nuclides other than may have contributed to the increased risk of thyroid cancer in the young following the Chernobyl reactor explosion (Dolphin, 1968 Boice, 2005, 2006). In comparison, rates of thyroid cancer were not increased in the more than 3000 children exposed to from the Hanford reactor site in an iodine-replete region (Davis et al, 2004). An increase in thyroid cancer has not been observed in about 6000 children who received for diagnostic procedures (Dickman etal, 2003 Boice, 2006). 

Sediments can act as both a repository for and a source of waterborne plutonium. Atmospheric fallout reaching surface water can settle in the sediments. The plutonium in the ocean sediments at Bikini Atoll, for example, was found to be resuspended and released to the bottom waters (Schell et al. 1980). In a freshwater waste pond at the Hanford reactor, plutonium was found to be bound to the sediments and was not available for uptake by plants or animals in the pond (Emery et al. 1980). The difference between the observations in the two ecosystems may be due to the dynamic nature of the ocean water near Bikini Atoll versus the relatively static nature of a waste water pond. 

HU-7 975> Reviev of Hanford Reactor Selsmoscope System, S W Nechodom,... 

One must understand that the uranium problem mobilized the best scientific brains of the time. Szilard, the brilliant visionary, and Fermi, the all-powerful experimental and theoretical genius, who actually achieved the first chain reaction, are unique and in a way unmatched. On the other hand, one must also recognize not that the chain reaction was so difficult to achieve, but that it was so easy. Lesser people than those who gathered at Chicago and Los Alamos could have succeeded - but could they have succeeded in only two years, the time from the first exponential experiment that showed k to exceed unity to the Hanford reactors and another year to Alamogordo ... 

Actually the original Hanford reactors operated for many years even though the graphite deteriorated (A.M.W.)... 

The Hanford reactor would produce 3.5 x 10 neutrinos per second. Wigner worried about whether the neutrinos could cause physiological effects in the workers at Hanford. In this paper Wigner dispels this concern. Neutrinos were first detected directly at Hanford by Heines and his associates some fifteen years after Wigner had made this calculation. 

The Wigner effect was once a potential problem in the Hanford reactors. However, since the graphite operating temperatures have been increased, the stored energy is released during the normal operating cycle and special annealing runs are not required. 

HW-74109 - Survey of Graphite Distortion and Burnout in Hanford Reactors. RW Benoliel and A Russell - June 27, 1962 - Secret. 

BW-74094, Hazards Summary Report - Six Oldest Hanford Reactors Vol. 1 - Hazards EveO-uation and Accident Analysii Vol. 2 - Process Control and Technical Data Vol. 3 - Description of Site and Facility... 

The parameter "A listed in the table Is a measure of the severity of the disturbance It is the ratio of the peak local power obtained in a free oscillation to the minlmuffl local power Amplitude ratios of the magnitudes indicated have never been obtained in any of the Hanford reactors... 

The startup transient curves Indicate the the maximum excess reactivity during startup and operation is the cold, clean reactivity. Turnaround reactivity level is below startup level. This differs from the present Hanford reactors where the turnaround level for an infinite-outage startup is higher than the initial cold clean reactivity level. 

In the present Hanford reactors > once the melting of uranium is accomplished the uranium d.U be redistributed in the lattice in such a fashion that a large loss of reactivity vlU result. The presence of hlgh-meltlng-polnt zlrconliua alloy process tubes In the NFR vlU delay the redistribution of uranium and thus It Is conceivable that physical effects unique to a zirconium tube reactor vlU occur. One such effect Is sluxoplng of the fuel element into a more favorable shape as far as neutron economy Is concerned. 

Ciray W.J. and Morgan W.C.. Leaching of C and Cl from Hanford Reactor Ciraphite" Pacific Northwest Laboratory Report PNL-6769. 1988... 

Figure 42. Detenniiiation of Columbia River flow tunes using radionuclide tracers released by the Hanford reactors, (a) Site map of Columbia River from Priest Rapids to mouth, (b) in Columbia River samples from six locations. From J. L. Nelson et al. (1966).

Nelson, J. L., R. W. Perkins, and W. L. Haushild. 1966. Determination of Columbia River flow times downstream from Pasco, Washington, using radioactive tracers introduced by the Hanford reactors. Water Resour. Res. 2(l) 31-39. 

Like the other Hanford reactors, N Reactor is a converter - the principal nuclear processes being the transmutation of to Pu 39 and the fissioning of... 

---