Uranium mills radioactivity

The licensing process consists of two steps construction and operating license that must be completed before fuel loading. Licensing covers radiological safety, environmental protection, and antitru,st considerations. Activities not defined as production or utilization of special nuclear material (SNM), use simple one-step. Materials Licenses, for the possession of radioactive materials. Examples are uranium mills, solution recovery plants, UO fabrication plants, interim spent fuel storage, and isotopic separation plants. 

Radium, thorium, and other radionuclides accumulate in uranium mill tailings. The potential environmental effects of these radionuclides has become of increasing concern to the public. In the future, it may be necessary to modify existing uranium recovery processes to accommodate removal of radium and perhaps other radioactive decay products of uranium. 

A significantly (p<0.05) increased incidence of malignancies in the lymphatic and hematopoietic tissues of uranium mill workers (cohort of 662 males) was found by Archer et al. (1973). The radioactivity in the tracheobronchial lymph nodes of the workers was found to be primarily the result of alpha emissions from thorium-230 and not from uranium-234 or uranium-238. Consequently, the authors suggested that the increased incidence of malignancies may have been a result of thorium-230 exposure and not uranium exposure. Exposure levels of thorium were not reported therefore, the results of the study are not reported on Table 2-1 or plotted in Figure 2-1. 

Fernades, H. M., Franklin, M. R., Veiga, L. H. S., Freitas, P. Gomiero, L. A. 1996. Management of uranium mill tailing geochemical processes and radiological risk assessment. Journal of Environmental Radioactivity, 30, 69-95. 

EPA has also decided that any accidental uranium waste containing 0.1 curies of radioactivity (150 kilograms) must be cleaned up. EPA calls this the Reportable Quantity Accidental Release. EPA also has established a standard for uranium mill tailings, hi the workplace, NIOSH/OSHA has set a Recommended Exposure Limit (REL) and a Permissible Exposure Limit (PEL) of 0.05 mg/m (34 pCi/m ) for uranium dust, while the NRC has an occupational limit of 0.2 mg/m (130 pCi/m ). The NRC has set uranium release limits at 0.06 pCi/m (0.09 pg/m ) of air and 300 pCi/liter (450 pg/liter) of water. NRC and OSHA expect that the public will normally be exposed to much lower concentrations. For more information about recommendations the federal government has made to protect your health, see Chapter 7. 

Radioactive waste containing uranium is usually grouped into three categories uranium mill tailings, low-level waste, and, in the case of spent reactor fuel, high-level waste. 

Bigu J, Duport P. 1992. Charcaterization of long-lived radioactive dust in uranium mill operations. 

Brookins DG, Thomson BM, Longmire PA, et al. 1993. Geochemical behavior or uranium mill tailings leachate in the subsurface. Radioactive Waste Management and the Nuclear Fuel Cycle 17(3-4) 269-287. 

Fort CW, Jr., Douglas RL, Moore WE. 1980. Radioactive emissions from yellowcake processing stacks at uranium mills. Report ISS ORP/LV-80-3. NTIS PB81-153389. 

Hans J Jr., Burris E, Gorsuch T. 1979. Radioactive waste management at the former Shiprock Uranium Mill Site New-Mexico, USA. In 24th Annual meeting of the Health Physics Society. Health Phys 37 811. 

Momeni MH, Kisieleski WE. 1980. Measured concentrations of radioactive particles in air in the vicinity of the Anaconda uranium mill [Bluewater, New Mexico]. Report ISS NUREG/CR-1320, ANL/ES-89. 

The principal effluents carrying radioactive material from a uranium mill are the following ... 

The amounts of these radioactive effluents have been estimated [S2] for two model uranium mills, each with a capacity of 2000 short tons of ore containing 0.2 percent U30g/day. One mill uses a carbonate leach, sodium hydroxide precipitation flow sheet such as that described in Sec. 8.4. The other mill uses an acid-leach, amine extraction flow sheet such... 

Table 5.24 Aiibome radioactive effluents from modd uranium mill and 20 years tailings storage ...

Differences among uranium mills and the ores they process will cause the amounts of radioactivity in individual mills to vary considerably from the estimates given above. 

AR509 3.59 Methods for estimating radioactive and toxic airborne source terms for uranium milling... 

The act does not cover radioactive waste, which falls imder the Atomic Energy Act of 1954. Later, the Uranium Mill TaiUngs Radiation Control Act of 1978 gave the EPA responsibility for cleanup of radioactive materials from inactive uranium processing sites. RCRA does not include water pollutants regulated by the Clean Water Act of 1972. Also excluded by RCRA were boiler fuel incinerators. Many... 

Thus, LLRW is defined more by what it is not than by what it is, that is, LLRW is defined by exclusion. LLRW is radioactive waste that is not HLRW, TRU waste, SNF, or byproduct material (commonly referred to as uranium mill tailings). All of these have separate legal definitions. Naturally occurring radioactive material and technologically enhanced NORM are also defined separately from LLRW but are not currently regulated under federal statute. 

Board on Radioactive Waste Management, Scientific Basis for Risk Assessment and Management of Uranium Mill Tailings, National Acadany Press (1986). 

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