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NTP_Eades_PhD.pdf (13.95 MB)
ETD Abstract Container
Abstract Header
135
Xe in LEU Cermet Nuclear Thermal Propulsion Systems
Author Info
Eades, Michael J., Eades
Permalink:
http://rave.ohiolink.edu/etdc/view?acc_num=osu1468426881
Abstract Details
Year and Degree
2016, Doctor of Philosophy, Ohio State University, Nuclear Engineering.
Abstract
Nuclear Thermal Propulsion (NTP) is currently a topic of research for NASA. NASA has the goal of sending humans to Mars and Nuclear Thermal Propulsion (NTP) is an appealing technology to aid in this endeavor. In the simplest terms, an NTP system is a nuclear reactor that utilizes hydrogen that is expanded through a convergent-divergent nozzle and ejected for propulsion. NTP can shorten the travel time to Mars and reduce the mass that must be lifted into low earth orbit. Furthermore, strategies to use low enriched uranium (LEU) in NTP systems have been identified which could make NTP significantly more affordable to develop than for past NTP development efforts. Beyond a human Mars mission, NTP has the potential to assist in other human and robotic missions beyond low earth orbit. The overarching goal of this work is to better understand NTP technology so that it may one day help with a human Mars mission. This work focuses on a subset of NTP systems that use a combination of LEU and tungsten cermet fuel and addresses the issues related to
135
Xe in these systems. LEU cermet NTP systems have a unique operational regime where
135
Xe has a profound impact on performance and controllability. LEU cermet NTP have extremely high power densities, operate with a thermal neutron spectrum, and the reference human mission to Mars requires restarting the reactor 4 to 8 hour after full power operation. In this work, two LEU cermet NTP point designs are presented and used as reference systems for the study of
135
Xe in LEU cermet NTP systems. These point designs were produced with a thorough search of the rocket performance design space. Using infinite lattice burnup calculations, it was found that MCNP 6.1.1 Beta and Serpent 2 produced very similar results and that burnup cells across the fuel element were not needed to capture spatial self shielding effects. The infinite lattice results were used to inform the approach undertaken for the full core burnup calculations. Full core burnup calculations indicate that the reactivity loss during operation of a LEU cermet NTP system has a maximum value of 210 pcm during a 25 minute burn and the maximum reactivity loss after operation peaks at approximately 3500 pcm. The possible effect of
135m
Xe on xenon worth in LEU cermet NTP systems was found by using the model based TENDL-2014 nuclear data library and Serpent 2. Model based TENDL cross sections were used because no experimentally determined cross sections are available for
135m
Xe. A relationship to estimate the performance (in terms of Isp loss) as a function of control drum angle is derived and presented. Mitigation strategies are identified that show promise for counteracting the effects of
135
Xe and maximizing the performance of LEU cermet NTP systems. It is recommended for future work that an integrated reactor systems code be developed to examine
135
Xe in LEU cermet NTP more thoroughly. In addition, this work has identified a need for basic nuclear data experiments to measure the cross section of
135m
Xe instead of relying on models.
Committee
Blue Thomas (Advisor)
Aldemir Tunc (Committee Member)
Cao Lei (Committee Member)
Pages
149 p.
Subject Headings
Nuclear Engineering
Keywords
Xenon-135, Space Nuclear, Nuclear Thermal Propulsion, Xe-135m
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Refworks
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Citations
Eades, Eades, M. J. (2016).
135
Xe in LEU Cermet Nuclear Thermal Propulsion Systems
[Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1468426881
APA Style (7th edition)
Eades, Eades, Michael.
135
Xe in LEU Cermet Nuclear Thermal Propulsion Systems.
2016. Ohio State University, Doctoral dissertation.
OhioLINK Electronic Theses and Dissertations Center
, http://rave.ohiolink.edu/etdc/view?acc_num=osu1468426881.
MLA Style (8th edition)
Eades, Eades, Michael. "
135
Xe in LEU Cermet Nuclear Thermal Propulsion Systems." Doctoral dissertation, Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1468426881
Chicago Manual of Style (17th edition)
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Document number:
osu1468426881
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Copyright Info
© 2016, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.