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You searched for +publisher:"Georgia Tech" +contributor:("Ougouag, Abderrafi"). Showing records 1 – 3 of 3 total matches.

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1. Marquez, Matias G. Silicide fuel swelling behavior and its performance in I2S-LWR.

Degree: MS, Mechanical Engineering, 2015, Georgia Tech

The swelling mechanisms of U3Si2 under neutron irradiation in reactor conditions are not unequivocally known. The limited experimental evidence that is available suggests that the main driver of the swelling in this material would be fission gases accumulation at crystalline grain boundaries. The steps that lead to the accumulation of fission gases at these locations are multiple and complex. However, gradually, the gaseous fission products migrate by diffusion. Upon reaching a grain boundary, which acts as a trap, the gaseous fission products start to accumulate, thus leading to formation of bubbles and hence to swelling. Therefore, a quantitative model of swelling requires the incorporation of phenomena that increase the presence of grain boundaries and decrease grain sizes, thus creating sites for bubble formation and growth. It is assumed that grain boundary formation results from the conversion of stored energy from accumulated dislocations into energy for the formation of new grain boundaries.This thesis attempts to develop a quantitative model for grain subdivision in U3Si2 based on the above mentioned phenomena to verify the presence of this mechanism and to use in conjunction with swelling codes to evaluate the total swelling of the pellet in the reactor during its lifetime. Advisors/Committee Members: Petrovic, Bojan (advisor), Ougouag, Abderrafi (advisor), Deo, Chaitanya (committee member).

Subjects/Keywords: Silicide fuels; Swelling; Recrystallization; Grain subdivision; Nuclear fuel; Accident tolerant fuel; Advanced fuels; Rim effect; High burnup structure; Fuel performance

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APA (6th Edition):

Marquez, M. G. (2015). Silicide fuel swelling behavior and its performance in I2S-LWR. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/53970

Chicago Manual of Style (16th Edition):

Marquez, Matias G. “Silicide fuel swelling behavior and its performance in I2S-LWR.” 2015. Masters Thesis, Georgia Tech. Accessed April 22, 2019. http://hdl.handle.net/1853/53970.

MLA Handbook (7th Edition):

Marquez, Matias G. “Silicide fuel swelling behavior and its performance in I2S-LWR.” 2015. Web. 22 Apr 2019.

Vancouver:

Marquez MG. Silicide fuel swelling behavior and its performance in I2S-LWR. [Internet] [Masters thesis]. Georgia Tech; 2015. [cited 2019 Apr 22]. Available from: http://hdl.handle.net/1853/53970.

Council of Science Editors:

Marquez MG. Silicide fuel swelling behavior and its performance in I2S-LWR. [Masters Thesis]. Georgia Tech; 2015. Available from: http://hdl.handle.net/1853/53970


Georgia Tech

2. Pounders, Justin Michael. A coarse-mesh transport method for time-dependent reactor problems.

Degree: PhD, Nuclear and Radiological Engineering, 2010, Georgia Tech

A new solution technique is derived for the time-dependent transport equation. This approach extends the steady-state coarse-mesh transport method that is based on global-local decompositions of large (i.e. full-core) neutron transport problems. The new method is based on polynomial expansions of the space, angle and time variables in a response-based formulation of the transport equation. The local problem (coarse mesh) solutions, which are entirely decoupled from each other, are characterized by space-, angle- and time-dependent response functions. These response functions are, in turn, used to couple an arbitrary sequence of local problems to form the solution of a much larger global problem. In the current work, the local problem (response function) computations are performed using the Monte Carlo method, while the global (coupling) problem is solved deterministically. The spatial coupling is performed by orthogonal polynomial expansions of the partial currents on the local problem surfaces, and similarly, the timedependent response of the system (i.e. the time-varying flux) is computed by convolving the time-dependent surface partial currents and time-dependent volumetric sources against pre-computed time-dependent response kernels. Advisors/Committee Members: Rahnema, Farzad (Committee Chair), Forget, Benoit (Committee Member), Morely, Tom (Committee Member), Ougouag, Abderrafi (Committee Member), Petrovic, Bojan (Committee Member), Zhang, Dingkang (Committee Member).

Subjects/Keywords: Response method; Time-dependent neutron transport; Polynomials; Monte Carlo method; Nuclear power plants; Nuclear reactors Safety measures

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APA (6th Edition):

Pounders, J. M. (2010). A coarse-mesh transport method for time-dependent reactor problems. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/39586

Chicago Manual of Style (16th Edition):

Pounders, Justin Michael. “A coarse-mesh transport method for time-dependent reactor problems.” 2010. Doctoral Dissertation, Georgia Tech. Accessed April 22, 2019. http://hdl.handle.net/1853/39586.

MLA Handbook (7th Edition):

Pounders, Justin Michael. “A coarse-mesh transport method for time-dependent reactor problems.” 2010. Web. 22 Apr 2019.

Vancouver:

Pounders JM. A coarse-mesh transport method for time-dependent reactor problems. [Internet] [Doctoral dissertation]. Georgia Tech; 2010. [cited 2019 Apr 22]. Available from: http://hdl.handle.net/1853/39586.

Council of Science Editors:

Pounders JM. A coarse-mesh transport method for time-dependent reactor problems. [Doctoral Dissertation]. Georgia Tech; 2010. Available from: http://hdl.handle.net/1853/39586


Georgia Tech

3. Hudson, Nathanael Harrison. The Correction of Pebble Bed Reactor Nodal Cross Sections for the Effects of Leakage and Depletion History.

Degree: PhD, Nuclear and Radiological Engineering, 2006, Georgia Tech

An accurate and computationally fast method to generate nodal cross sections for the Pebble Bed Reactor (PBR) was presented. In this method, named Spectral History Correction (SHC), a set of fine group microscopic cross section libraries, pre-computed at specified depletion and moderation states, was coupled with the nodal nuclide densities and group bucklings to compute the new fine group spectrum for each node. The relevant fine group cross-section library was then recollapsed to the local broad group cross-section structure with this new fine group spectrum. This library set was tracked in terms of fuel isotopic densities. Fine group modulation factors (to correct the homogeneous flux for heterogeneous effects) and fission spectra were also stored with the cross section library. As the PBR simulation converges to a steady state fuel cycle, the initial nodal cross section library becomes inaccurate due to the burnup of the fuel and the neutron leakage into and out of the node. Because of the recirculation of discharged fuel pebbles with fresh fuel pebbles, a node can consist of a collection of pebbles at various burnup stages. To account for the nodal burnup, the microscopic cross sections were combined with nodal averaged atom densities to approximate the fine group macroscopic cross-sections for that node. These constructed, homogeneous macroscopic cross sections within the node were used to calculate a numerical solution for the fine group spectrum with B1 theory. This new fine spectrum was used to collapse the pre-computed microscopic cross section library to the broad group structure employed by the fuel cycle code. This SHC technique was developed and practically implemented as a subroutine within the PBR fuel cycle code PEBBED. The SHC subroutine was called to recalculate the broad group cross sections during the code convergence. The result was a fast method that compared favorably to the benchmark scheme of cross section calculation with the lattice cross-section generator for two PBR reactor designs. Advisors/Committee Members: Rahnema, Farzad (Committee Chair), Goldsztein, Guillermo (Committee Member), Ougouag, Abderrafi (Committee Member), Stacey, Weston (Committee Member), Wang, C.-K. Chris (Committee Member).

Subjects/Keywords: Cross sections; Nodal; Spectral history; Pebble bed reactor; Leakage; Depletion; PBR; PEBBED

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Hudson, N. H. (2006). The Correction of Pebble Bed Reactor Nodal Cross Sections for the Effects of Leakage and Depletion History. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/11485

Chicago Manual of Style (16th Edition):

Hudson, Nathanael Harrison. “The Correction of Pebble Bed Reactor Nodal Cross Sections for the Effects of Leakage and Depletion History.” 2006. Doctoral Dissertation, Georgia Tech. Accessed April 22, 2019. http://hdl.handle.net/1853/11485.

MLA Handbook (7th Edition):

Hudson, Nathanael Harrison. “The Correction of Pebble Bed Reactor Nodal Cross Sections for the Effects of Leakage and Depletion History.” 2006. Web. 22 Apr 2019.

Vancouver:

Hudson NH. The Correction of Pebble Bed Reactor Nodal Cross Sections for the Effects of Leakage and Depletion History. [Internet] [Doctoral dissertation]. Georgia Tech; 2006. [cited 2019 Apr 22]. Available from: http://hdl.handle.net/1853/11485.

Council of Science Editors:

Hudson NH. The Correction of Pebble Bed Reactor Nodal Cross Sections for the Effects of Leakage and Depletion History. [Doctoral Dissertation]. Georgia Tech; 2006. Available from: http://hdl.handle.net/1853/11485

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