Recovery of nonradioactive palladium and rhodium from high-level radioactive wastes
A possible method for recovering significant quantities of nonradioactive palladium from fission-product wastes requires essentially complete separation of the fission-product (radioactive) palladium from fission-product ruthenium. After the decay of /sup 106/Ru via /sup 106/Rh to /sup 106/Pd, this nonradioactive palladium is recovered for normal commercial use. The U.S. production of palladium has never been above 1000 kg per year vs consumption of about 46,000 kg per year. Most of the supply comes from Russia and South Africa. It has been estimated that a 400-GW(e) nuclear reactor economy will make available 2000 kg per year of /sup 106/Ru at reactor fuel discharge. A substantial increase might be achieved if plutonium were recycled as fissionable material because of the higher yields of the 106 chain from plutonium. A literature search has uncovered support for three promising approaches to the required separation of palladium from ruthenium: (1) recrystallization from solution in bismuth or in zinc; (2) selective precipitation of a titanium--ruthenium intermetallic compound from bismuth, followed by precipitation of a zinc--palladium intermetallic compound; and (3) dissolution in molten magnesium followed by partitioning between molten magnesium and a molten uranium-5 wt % chromium eutectic at a temperature above 870/sup 0/C. Liquid-liquid extraction appears to be the most promising method from a technological point of view, although intermetallic compound formation is much more interesting chemically. Recovery of some nonradioactive /sup 103/Rh may be possible by liquid-liquid extraction of the fuel before the decay of the 39.8-d /sup 103/Ru has gone substantially to completion. Demonstration of the practicality of these separations will contribute a positive factor to the evaluation of resumption in the United States of nuclear fuel reprocessing and plutonium recycle in light-water-moderated reactors.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- DOE Contract Number:
- W-7405-ENG-26
- OSTI ID:
- 6768063
- Report Number(s):
- ORNL/TM-6654; TRN: 79-003945
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
PALLADIUM
SEPARATION PROCESSES
RADIOACTIVE WASTE PROCESSING
HIGH-LEVEL RADIOACTIVE WASTES
RHODIUM
FISSION PRODUCTS
RECOVERY
ELEMENTS
ISOTOPES
MANAGEMENT
METALS
PLATINUM METALS
PROCESSING
RADIOACTIVE MATERIALS
RADIOACTIVE WASTES
REFRACTORY METALS
TRANSITION ELEMENTS
WASTE MANAGEMENT
WASTE PROCESSING
WASTES
052001* - Nuclear Fuels- Waste Processing
400103 - Radiometric & Radiochemical Procedures- (-1987)