scholarly journals 40 CFR 190. Environmental radiation protection requirements for normal operations of activities in the uranium fuel cycle. Final environmental statement. Volume II

1976 ◽  
Author(s):  
R. Thomas Peake ◽  
Daniel Schultheisz ◽  
Loren W. Setlow ◽  
Brian Littleton ◽  
Reid Rosnick ◽  
...  

The United States Environmental Protection Agency’s (EPA) Radiation Protection Division is the portion of EPA (or the Agency) that develops environmental standards for radioactive waste disposal in the United States. One current issue of concern is the disposal of low activity radioactive waste (LAW), including wastes that would be produced by a radiological dispersal device (RDD), for which current disposal options may be either inconsistent with the hazard presented by the material or logistically problematic. Another major issue is related to the resurgence in uranium mining. Over the past several years, demand for uranium for nuclear power plant fuel has increased as has the price. The increase in price has made uranium mining potentially profitable in the US. EPA is reviewing its relevant regulations, developed primarily in the 1980s, for potential revisions. For example, in-situ leaching (also known as in-situ recovery) is now the technology of choice where applicable, yet our current environmental standards are focused on conventional uranium milling. EPA has two actions in process, one related to the Clean Air Act, the other related to revising the environmental standards that implement the Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA). Separately, but related, EPA has developed over the last several years uranium mining documents that address technologically enhanced natural occurring radioactive materials (TENORM) from abandoned uranium mines, and wastes generated by active uranium extraction facilities. Lastly, in 1977 EPA developed environmental standards that address nuclear energy, fuel fabrication, reprocessing, and other aspects of the uranium fuel cycle. In light of the increased interest in nuclear power and the potential implementation of advanced fuel cycle technologies, the Agency is now reviewing the standards to determine their continued applicability for the twenty-first century.


2017 ◽  
Vol 175-176 ◽  
pp. 70-77 ◽  
Author(s):  
J. Guillén ◽  
A. Baeza ◽  
N.A. Beresford ◽  
M.D. Wood

Author(s):  
Boris A. Hombourger ◽  
Jiří Křepel ◽  
Konstantin Mikityuk ◽  
Andreas Pautz

Molten salt reactors (MSRs) are promising advanced nuclear reactors for closure of the fuel cycle. This paper discusses the core design of graphite-moderated MSRs, thanks to a parametric study of the fuel and moderator lattice. The study is conducted at equilibrium of the thorium-uranium fuel cycle for several fuel channel radius and moderator block size combinations. The equilibrium composition for each studied configuration is derived with the help of an in-house MATLAB code, EQL0D, which uses the Serpent 2 Monte Carlo neutronics code for the calculation of reaction rates. The results include excess reactivity at equilibrium, mirroring the breeding gain, and the actinide vector composition for each configuration. Moreover, the occurence of an optimum of the excess reactivity per percent uranium-233 was observed. The investigations showed that it is systematically seen at an interchannel distance equal to the neutron slowing-down length in graphite for each configuration and does not depend on the salt channel radius beyond a certain size, which is given by the thermal fission rate reaching the levels of the fast fission rate. In this way, an exotic energy and spatial distribution of the neutrons are attained. The investigations highlight the potential attractiveness, from a neutronics/fuel cycle point of view, of both large fuel channels and moderators with a shorter neutron slowing-down length.


2015 ◽  
Vol 68 (3) ◽  
pp. 566-572 ◽  
Author(s):  
S. C. Xiao ◽  
Jing Zhao ◽  
X. Heng ◽  
X. Y. Sheng ◽  
Z. Zhou ◽  
...  

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