Irradiated reactor fuel

Nuclear Waste. NRC defines high level radioactive waste to include (/) irradiated (spent) reactor fuel (2) Hquid waste resulting from the operation of the first cycle solvent extraction system, and the concentrated wastes from subsequent extraction cycles, in a faciHty for reprocessing irradiated reactor fuel and (3) soHds into which such Hquid wastes have been converted. Approximately 23,000 metric tons of spent nuclear fuel has been stored at commercial nuclear reactors as of 1991. This amount is expected to double by the year 2001. 

Large-scale plutonium recovery/processing facilities originated at Los Alamos and Hanford as part of the Manhattan Project in 1943. Hanford Operations separated plutonium from irradiated reactor fuel, whereas Los Alamos purified plutonium, as well as recovered the plutonium from scrap and residues. In the 1950 s, similar processing facilities were constructed at Rocky Flats and Savannah River. 

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. 

Plutonium Scrap Processing. In addition to recovering plutonium from irradiated reactor fuel, a Plutonium Reclamation Facility (PRF)( 7,8) is operated at the Hanford site to recover, separate, and purTfy kilogram amounts of plutonium from a wide range of unirradiated scrap materials. A 20 percent TBP-CC1 k solution is used to extract Pu(IV) from HN03-HF-A1(N03)3 solutions of dissolved scrap. 

The group of radionuclides to be considered are the ones produced by nuclear explosions and the ones present in the irradiated reactor fuel. This group comprises several hundred radionuclides, but only a limited number of them contributes significantly to human exposure. These would normally include fission products and activation products. Radioactive noble gases, e.g. Kr, Xe, are not considered since they are unlikely to contribute significantly to internal exposure via the food chain. 

Although packed columns are simple and have no moving parts, their large space requirements have resulted in the replacement of packed columns by pulsed columns, or by other more compact contactors, in more recent installations for reprocessing irradiated reactor fuel. 

The radioactive decay properties of the plutonium isotopes that appear in irradiated reactor fuel are listed in Table 9.14. All but Pu and Pu are alpha emitters. Because it penetrates matter only weakly, alpha radiation is stopped by the outer layer of dead skin and is not a hazard outside the body. However, plutonium is very effective biologically when deposited in or on living tissue, particularly if by inhalation or by contaminated injuries. Pu is a relatively short-lived (13.2-year... 

The chemistry involved in the isolation and purification of the actinide elements from irradiated reactor fuel elemmts is further discussed in Chapter 21. Actinide chemistry in the ecosphere is discussed in 22.6. 

Observation of the Cherenkov radiation from irradiated reactor fuel assemblies is used to obtain qualitative confirmation (attribute testing) of the presence of spent fuel in storage by scanning rows of assemblies from the pool bridge. Characteristic patterns formed by the arrangements of rods and holes in fuel assemblies have to be observed to ensure a valid verification. A well-trained inspector can easily detect the presence of an inactive dummy assembly surrounded by highly active neighbors. 

Emphasis on irradiated reactor fuel. Present needs am>arently satisfied, but predicted large-mqiacity requirements would require the use of soluble poisons for primary protection, and better data on poisoned lattices. ... 

Reprocessing of highly enriched irradiated reactor fuel at the Idaho Chemical Processing Plant (ICPP) presents significant problems to the Criticality Safety (CS) and Safeguards Security (S S) Sections. Two major interactions between these sections occur when irradiated fuel is stored and fuel b dissolved. 

Mironov, V.P., Matusevich, J.L., Kudijashov, V.P. et al. (2005). Determination of uranium concentration and bum-up of irradiated reactor fuel in contaminated areas in Belarus using uranium isotopic ratios in soil samples, Radiochim. Acta 93,781—784. 

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