Design of a Low Enrichment, Enhanced Fast Flux Core for the Massachusetts Institute of Technology Research Reactor
Design of a Low Enrichment, Enhanced Fast Flux Core for the Massachusetts Institute of Technology Research Reactor

Author: Tyler Shawn Ellis

Publisher:

Published: 2008

Total Pages: 127

ISBN-13:

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(Cont.) This new core fast flux capability is within a factor of 2 to 4 of the much larger national test reactors, the Advanced Test Reactor and the High Flux Isotope Reactor, and hence can allow the MIT research reactor to be more useful for fast irradiation. The work covered both steady state and transient events involving the Fast Flux Trap, using the Monte Carlo N-Particle (MCNP) transport code. It was shown that the power distribution within the Fast Flux Trap pins as well as the plates in the rest of the core will be satisfactory; or in other words, no excessive power peaking will develop. The limits of the Fast Flux Trap lifetime were found to exceed the expected licensing time of the new core. Furthermore, the reactivity implications of metallic coolant leaks, water flooding of the Fast Flux Trap and various possible test materials were all found to be acceptable. The loss of flow following a pump trip event was analyzed using the RELAP5-3D code, and found not to result in excessive temperatures with regards to materials strength and corrosion resistance. While the specific design developed in this dissertation is particular to the MIT research reactor core, the Fast Flux Trap design concept can potentially be applied in other reactor cores so that other thermal spectrum research and test reactor facilities can benefit from this enhanced capability.

Development of a Low Enrichment Uranium Core for the MIT Reactor
Development of a Low Enrichment Uranium Core for the MIT Reactor

Author: Thomas Henderson Newton

Publisher:

Published: 2006

Total Pages: 312

ISBN-13:

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(cont.) Thermal-hydraulic calculations using the multi-channel thermal-hydraulics analysis code MULCH-II indicated that the peak power channel will remain below the Onset of Nucleate Boiling under all normal operating conditions as well as loss of flow conditions. In addition, using MCNP and the thermal-hydraulics/point kinetics code PARET it was shown that all reactivity coefficients were negative and that the LEU core could withstand a step reactivity insertion of $3.69 without reaching cladding softening temperature, thus increasing the allowable reactivity for an incore experiment. Finally, it is possible to use the proposed design to increase the neutron flux by increasing core power, but with a correspondingly reduced refueling cycle length.

Design and Optimization of a High Thermal Flux Research Reactor Via Kriging-based Algorithm
Design and Optimization of a High Thermal Flux Research Reactor Via Kriging-based Algorithm

Author: Stephanie Anne Kempf

Publisher:

Published: 2011

Total Pages: 280

ISBN-13:

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In response to increasing demands for the services of research reactors, a 5 MW LEU-fueled research reactor core is developed and optimized to provide high thermal flux within specified limits upon thermal hydraulic performance, cycle length, irradiation utilization, and manufacturability. A novel fuel assembly concept which makes use of integral flux traps is postulated to meet these requirements. Each assembly can be rotated into one of three different configurations to produce flux traps of different size, shape, and neutron energy spectrum within the core. A method for predicting and guiding the search for the optimum geometry was sought. Kriging has been chosen to predict the values of eigenvalue and thermal flux at untested geometric parameters. Because kriging treats all measurements as the sum of a global deterministic function and a stochastic departure from that function, predictions come with a measurement of uncertainty. As a result, the analyst can search the design space for likely improvement, or probe areas of high uncertainty for improvements that might have been missed using other methods. The technique is used in an algorithm for constrained optimization of the design, and a set of best practices for use of this are described. The optimized design produces a peak thermal flux of 1.56 x 1014 n/cm2s. Safety is demonstrated by presentation of reactivity feedback coefficients and the results of loss of flow and reactivity insertion transient analysis. A single fission target can be used to produce 96 6-day Ci of 99Mo per week. When the reactor is oriented to take advantage of high fast flux, steels can be subjected to damage rates of 5.76 dpa per year. Silicon carbide can be damaged at a rate of 2.79 dpa/y. The concept is a safe, versatile, proliferation-resistant means of supplying current and future irradiation needs.

Nuclear Engineering
Nuclear Engineering

Author: Zafar Ullah Koreshi

Publisher: Academic Press

Published: 2022-03-23

Total Pages: 549

ISBN-13: 0323908314

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Nuclear Engineering Mathematical Modeling and Simulation presents the mathematical modeling of neutron diffusion and transport. Aimed at students and early career engineers, this highly practical and visual resource guides the reader through computer simulations using the Monte Carlo Method which can be applied to a variety of applications, including power generation, criticality assemblies, nuclear detection systems, and nuclear medicine to name a few. The book covers optimization in both the traditional deterministic framework of variational methods and the stochastic framework of Monte Carlo methods. Specific sections cover the fundamentals of nuclear physics, computer codes used for neutron and photon radiation transport simulations, applications of analyses and simulations, optimization techniques for both fixed-source and multiplying systems, and various simulations in the medical area where radioisotopes are used in cancer treatment. Provides a highly visual and practical reference that includes mathematical modeling, formulations, models and methods throughout Includes all current major computer codes, such as ANISN, MCNP and MATLAB for user coding and analysis Guides the reader through simulations for the design optimization of both present-day and future nuclear systems

Development of a Core Design Optimization Tool and Analysis in Support of the Planned Low Enriched Uranium Conversion of the MIT Research Reactor (MITR-II)
Development of a Core Design Optimization Tool and Analysis in Support of the Planned Low Enriched Uranium Conversion of the MIT Research Reactor (MITR-II)

Author: Heather Moira Connaway

Publisher:

Published: 2012

Total Pages: 185

ISBN-13:

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The MIT Research Reactor (MITR-II) is currently undergoing analysis for the planned conversion from high enriched uranium (HEU) to low enriched uranium (LEU), as part of a global effort to minimize the availability of weapons-grade uranium. In support of efficient fuel management analysis with the new LEU fuel, a core design optimization tool has been developed. Using a coarse model, the tool can quickly consider the large range of refueling options available, and identify a solution which minimizes power peaking with the least fuel shuffling possible. The selected scheme can then be examined in greater detail with a more robust simulation tool. The unique geometry of the MITR core makes it difficult to develop a model that both runs very quickly and provides detailed power distribution information. Therefore, a correlation-based approach has been employed. Relationships between burnup, critical control blade position, core Um mass, and power distribution are used to predict fuel element U235 depletion, critical control blade motion, and power peaking. The tool applies the correlations to identify an optimal loading pattern, defined as the core which has the lowest maximum radial peaking factor in the set of valid solutions with the minimum number of fuel shuffling actions. The correlations that are utilized by the optimization tool were developed using data from simulations with MCODE-FM, a fuel management wrapper for the MCNP-ORIGEN linkage code MCODE. The correlations have been verified with results from additional MCODE-FM runs, and the code logic has been verified with the core loading solutions for a variety of input parameters. The verification found that the code is able to predict radial peaking, core mass, and general control blade motion with sufficient accuracy to develop a good refueling scheme. The tool provides the output solution in an interactive format, which allows the user to quickly examine small perturbations on the identified loading pattern. In addition to the optimization tool development, loading patterns for the mixed HEU-LEU fuel transition cores have been evaluated. This analysis identified general behavioral trends of the mixed-fuel cores, which serve as an initial basis for future transition core analysis.

Progress, Challenges, and Opportunities for Converting U.S. and Russian Research Reactors
Progress, Challenges, and Opportunities for Converting U.S. and Russian Research Reactors

Author: Russian Academy of Sciences

Publisher: National Academies Press

Published: 2012-03-24

Total Pages: 126

ISBN-13: 0309253209

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Highly enriched uranium (HEU) is used for two major civilian purposes: as fuel for research reactors and as targets for medical isotope production. This material can be dangerous in the wrong hands. Stolen or diverted HEU can be used-in conjunction with some knowledge of physics-to build nuclear explosive devices. Thus, the continued civilian use of HEU is of concern particularly because this material may not be uniformly well-protected. To address these concerns, the National Research Council (NRC) of the U.S. National Academies and the Russian Academy of Sciences (RAS) held a joint symposium on June 8-10, 2011. Progress, Challenges, and Opportunities for Converting U.S. and Russian Research Reactors summarizes the proceedings of this joint symposium. This report addresses: (1) recent progress on conversion of research reactors, with a focus on U.S.- and R.F.-origin reactors; (2) lessons learned for overcoming conversion challenges, increasing the effectiveness of research reactor use, and enabling new reactor missions; (3) future research reactor conversion plans, challenges, and opportunities; and (4) actions that could be taken by U.S. and Russian organizations to promote conversion. The agenda for the symposium is provided in Appendix A, biographical sketches of the committee members are provided in Appendix B, and the report concludes with the statement of task in Appendix C.

Optimized Core Design of a Supercritical Carbon Dioxide-cooled Fast Reactor
Optimized Core Design of a Supercritical Carbon Dioxide-cooled Fast Reactor

Author: Christopher Stanley Handwerk

Publisher:

Published: 2007

Total Pages: 367

ISBN-13:

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(Cont.) Alternative cores using traditional pin-type fuel and innovative Internally-Cooled Annular Fuel (ICAF) have also been evaluated. While the performance of the TID core is superior, the results of the pin-type core show promise, pending design modification and relaxation of the imposed core pressure drop constraint, which would come at the expense of cycle efficiency and increased decay heat removal power requirements. Nevertheless, no improvement would be able to achieve a sustainable core (i.e. conversion ratio=l) using oxide fuel without the use of external blankets for pin fuel, even without the use of diluent in the fuel. A comprehensive comparison of the thermal hydraulic and neutronic performance of TID fuel with that of the traditional pin-type fuel, as well as with the ICAF is also made, showing the fundamental reasons for their difference in performance.