An important improvement in the area of reactor core neutronic modeling is the development and use of the methods based on "quasi-diffusion" (QD) low-order equations. This family of methods takes into account the transport exactly using "functionals" computed by solving transport equations, and is amenable to solution with a variety...
The nuclear industry has long relied upon bounding parametric analyses in predicting the safety margins of reactor designs undergoing design-basis accidents. These methods have been known to return highly-conservative results, limiting the operating conditions of the reactor. The Best-Estimate Plus Uncertainty (BEPU) method using a modernized version of the Code-Scaling,...
The intent of this work is to extend Implicit Monte Carlo Diffusion (IMD)[Gen.
2001] to account for frequency dependence and to incorporate the difference formulation[Szo. 2005] as a source manipulation variance reduction technique. This
work shows the derivation of the probabilities and the associated proofs which
govern the frequency dependent...
Transport in a binary stochastic media has been an area of interest for many applications over the past three decades. Many different methods have been attempted, most based on the Levermore-Pomraning coupled transport model. However, this method has never been able to correctly solve problems where a large amount of...
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Todd S. Palmer
Transport in a binary stochastic media has been an area of interest for many
We investigate several aspects of the numerical solution of the radiative transfer
equation in the context of coal combustion: the parallel efficiency of two commonly used
opacity models, the sensitivity of turbulent radiation interaction (TRI) effects
to the presence of coal particulate, and an improvement of the order of temporal...
The most widely used and versatile medical radioisotope today is technetium-99m. Roughly 30 million people depend on this radioisotope for diagnostic procedures each year, and this demand is expected to grow. Although there are numerous ways of procuring this isotope, the most common and most practical, for reasons to be...
Antineutrino detectors could provide a valuable addition to current safeguards
regimes. Antineutrinos are an attractive emission to monitor due to their low
interaction cross-section that prevents them from being shielded and the dependence
of their spectrum on the power level and isotopic content of a reactor core. While
there are...
Oregon State University has recently conducted a complete core conversion analysis as part of the Reduced Enrichment for Research and Test Reactors Pprogram. The goals of the thermal hydraulic analyses were to calculate natural circulation flow rates, coolant temperatures and fuel temperatures as a function of core power for both...
The United States (US) Department of Energy (DOE) has identified the pebble-bed reactor as a high priority for US research with the end goal of licensing a pebble-bed reactor (PBR) for operation in the United States. Before this can be accomplished significant research must be done regarding the safety of...
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Brian G. Woods
The United States (US) Department of Energy (DOE) has identified the pebble
This thesis presents a feasibility study of a thorium fueled thermal spectrum breeder-burner reactor that operates without chemical reprocessing. Materials were evaluated for their potential as moderators using standard analytical methods. These materials were then used as moderators to evaluate criticality and enrichment in an infinite fuel pin lattice. The...
Attila is a state-of-the-art radiation transport based code that is efficient, accurate and straightforward to use. Geometric information is input to the code as CAD drawings. Material property information is input as a cross section library. The user has full control over standard transport options and output reports.
In phase...
Since the 1990s, researchers around the world have been creating antineutrino detectors for monitoring power reactors. These detectors have been deployed at light water reactors and are able to determine power levels and burn up throughout a fuel cycle. This technology could allow the IAEA to monitor LWRs remotely and...
Interest in increased fuel supply stability has driven an investigation into possible alternate fuel for use in the WWR-SM research reactor at the Institute of Nuclear Physics in Uzbekistan. The WWR-SM is a high-power, pool-type research reactor currently utilizing IRT-4M fuel made by a single Russian supplier. A candidate for...
Characteristic methods are widely known to be very accurate approaches to the
solution of numerical transport problems. These methods are most often used for
neutron transport applications (i.e. lattice physics calculations) where spatial cells
are of intermediate optical thickness (O(1) - O(100) mean free paths, depending on
the energy group)...
Human cathelicidin antimicrobial peptide (CAMP/LL-37) is a cationic antimicrobial peptide that is widely expressed by myeloid and epithelial cells at the human-environment interface. It possesses broad spectrum antimicrobial capacity against bacteria, fungi and viruses. In addition to its direct antimicrobial activity, CAMP/LL-37 also attracts and recruits monocytes, neutrophils and other...
In this dissertation, we derive and implement a new transport-diffusion hybrid algorithm for solving thermal radiative transfer (TRT) problems. Using the method of nonlinear elimination (NLEM), the TRT system of equations can be written in terms of a transport equation with the absence of scattering and a diffusion equation. The...
The implementation of advanced hybrid (Monte Carlo/Deterministic) transport methods for realistic test problems has been a challenge due to the overhead efforts associated with interfacing a solution generated by a deterministic solver with a Monte Carlo based radiation transport code. In this work, with the help of Transpire, Inc., a...
Circulating fuel reactor (CFR) kinetics are characterized by delayed neutron precursor (DNP) drift in addition to the neutronic and thermal hydraulic phenomena typical of other reactor types. This environment can be computationally challenging to model, given that the multiphysics phenomena generally have non-linear interdependencies requiring the use of iterative solution...
This is the investigation into The generation of high-fidelity multigroup multiband cross sections from Monte Carlo neutron transport simulations. Previous methods for generating multigroup multiband (MGMB) cross sections, and multigroup cross sections, assume an approximate shape for the scalar flux. This approximate flux shape is the product of an energy-dependent...