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Fuel Cycle & Waste Management
Devoted to all aspects of the nuclear fuel cycle including waste management, worldwide. Division specific areas of interest and involvement include uranium conversion and enrichment; fuel fabrication, management (in-core and ex-core) and recycle; transportation; safeguards; high-level, low-level and mixed waste management and disposal; public policy and program management; decontamination and decommissioning environmental restoration; and excess weapons materials disposition.
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Conference on Nuclear Training and Education: A Biennial International Forum (CONTE 2025)
February 3–6, 2025
Amelia Island, FL|Omni Amelia Island Resort
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The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
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Senate committee hears from energy secretary nominee Chris Wright
Wright
Chris Wright, president-elect Trump’s pick to lead the U.S. Department of Energy, spent hours today fielding questions from members of the U.S. Senate’s committee on Energy and Natural Resources.
During the hearing, Wright—who’s spent most of his career in fossil fuels—made comments in support of nuclear energy and efforts to expand domestic generation in the near future. Asked what actions he would take as energy secretary to improve the development and deployment of SMRs, Wright said: “It’s a big challenge, and I’m new to government, so I can’t list off the five levers I can pull. But (I’ve been in discussions) about how to make it easier to research, to invest, to build things. The DOE has land at some of its facilities that can be helpful in this regard.”
J. Vujic, E. Greenspan
Nuclear Science and Engineering | Volume 129 | Number 1 | May 1998 | Pages 1-14
Technical Paper | doi.org/10.13182/NSE98-A1960
Articles are hosted by Taylor and Francis Online.
Neutronic characteristics are investigated of critical configurations consisting of U and moist rock, which may be formed if large enough quantities of highly enriched U (HEU) are released, transported, and deposited in the rock below the repository. A companion study investigated neutronic characteristics of similar critical configurations consisting of weapons-grade Pu (wPu) and moist rock.Two modes of U deposition are considered: uniform homogeneous and heterogeneous. The latter is assumed to be of the form of thin planar deposition layers separated by relatively thick slabs of rock, making a constant pitch lattice. Three neutronic characteristics are examined: the critical U loading, and the variation, with the change of operating conditions, of the multiplication factor k; the time-eigenvalue ; and the effective neutron generation time . They are compared against the characteristics of the corresponding wPu-rock systems. The study is done parametrically by solving time-independent transport equations. The effect of various mechanisms (including water removal, U and rock temperature increase, homogenization of fissile and rock materials, and the system expansion) on the neutronic characteristics is studied independently.A surprising finding is that heterogeneous depositions of HEU in moist rock can have a positive reactivity feedback due to spectrum hardening. Moreover, the magnitude and temperature dependence of heterogeneous U-rock systems can be comparable to those of Pu-rock systems despite the fact that they are due to entirely different mechanisms: reduction in the spatial self-shielding in the HEU systems compared with an increase in the effective fission-to-absorption cross-section ratio in the wPu systems.It is concluded that heterogeneous HEU deposits in moist rock can be just about as autocatalytic as critical wPu deposits but require approximately twice the critical mass. Three mechanisms were found to have a potential for a large positive reactivity insertion: water removal, rock temperature increase, and homogenization. The magnitude of each of the three positive reactivity feedbacks in the HEU systems is similar to the magnitude in the corresponding wPu systems.
