Nuclear Engineering Commons^™

Impact Investigation Of Reactor Fuel Operating Parameters On Reactivity For Use In Burnup Credit Applications, Tanya N. Sloma

UNLV Theses, Dissertations, Professional Papers, and Capstones

When representing the behavior of commercial spent nuclear fuel (SNF), credit is sought for the reduced reactivity associated with the net depletion of fissile isotopes and the creation of neutron-absorbing isotopes, a process that begins when a commercial nuclear reactor is first operated at power. Burnup credit accounts for the reduced reactivity potential of a fuel assembly and varies with the fuel burnup, cooling time, and the initial enrichment of fissile material in the fuel. With regard to long-term SNF disposal and transportation, tremendous benefits, such as increased capacity, flexibility of design and system operations, and reduced overall costs, provide …

A Safeguards Design Strategy For Domestic Nuclear Materials Processing Facilities., Jonathan Long

Electronic Theses and Dissertations

The outdated and oversized nuclear manufacturing complex within the United States requires its transformation into a smaller, safe, and secure enterprise. Health and safety risks, environmental concerns, and the end of the Cold War have all contributed to this necessity. The events of September 11, 2001, emphasized the protection requirements for nuclear materials within the U.S. as well as abroad.

Current Nuclear Safeguards regulations contain minimal prescriptive requirements relating to the design of new production facilities. Project management and engineering design guides require that design documents contain specific and measureable statements relating to systems requirements. The systems engineering process evaluates …

Flow Rate Measurement In A High Temperature, Radioactive, And Corrosive Environment, Taleb Moazzeni

UNLV Theses, Dissertations, Professional Papers, and Capstones

Accurate measurement of coolant flow rate is essential for determining the maximum power required by the nuclear plant operation and critical for monitoring its operation safety. However, no practical off-the-shelf flowmeter is available to satisfy all the pressing multidimensional operation requirements (i. e., high temperature, high irradiation, and high corrosion). This work thus deals with the development of a new flowmeter for nuclear power plant/reactor process-monitoring and real time analysis; this proposed flowmeter shall be able to continuously conduct robust measurements under extremely harsh environment with high irradiation, high pressure, high temperature and corrosive media. We investigate a transit-time based …

In-Pile Thermal Conductivity Measurement Methods For Nuclear Fuels, Brandon S. Fox

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Measuring nuclear fuel thermal conductivity in-pile can provide much needed data for understanding fuel performance during irradiation and yield thermophysical property data needed for simulation codes and fuel databases. The objective of this research is to develop and compare two in-pile thermal conductivity methods in a laboratory setting using surrogate fuel materials.

A steady-state radial heat flow method was investigated to understand its viability as an in-pile steady-state thermal conductivity technique. By using Joule heating to simulate volumetric heat generation within a surrogate fuel rod, thermal conductivity was measured with two thermocouples at different radial positions within the rod. Examinations …

Gadolinium Oxide/Silicon Thin Film Heterojunction Solid-State Neutron Detector, Christopher M. Young

Theses and Dissertations

The internal conversion electron emission from the de-excitation of the Gd-158m nucleus was explored as a means for neutron detection. Thin film gadolinium oxide (Gd₂O₃) and p-type silicon heterojunction diodes were produced using a supercritical water deposition process. Pulse height spectroscopy was conducted on the novel diodes while they were subjected to a moderated plutonium-beryllium (PuBe) source flux of 10⁴ thermal neutrons/cm² s. Coincident gamma spectroscopy was employed to verify the 1107.6 keV photon emissions from the diode indicative of successful neutron capture by Gd-157 and the subsequent de-excitation of the Gd-158m nucleus. Neutron …

Bennett Clocking Of Nanomagnetic Logic Using Multiferroic Single-Domain Nanomagnets, Jayasimha Atulasimha, Supriyo Bandyopadhyay

Mechanical and Nuclear Engineering Publications

The authors show that it is possible to rotate the magnetization of a multiferroic (strain-coupled two-layer magnetostrictive-piezoelectric)nanomagnet by a large angle with a small electrostatic potential. This can implement Bennett clocking [Int. J. Theor. Phys.21, 905 (1982)] in nanomagnetic logic arrays resulting in unidirectional propagation of logic bits from one stage to another. This method is potentially more energy efficient than using spin-transfer torque for magnetization rotation. For realistic parameters, it is shown that a potential of ∼0.2 V applied to a multiferroicnanomagnet can rotate magnetization by nearly 90° to implement Bennett clocking.

Dead Time And Count Loss Determination For Radiation Detection Systems In High Count Rate Applications, Amol Patil

Doctoral Dissertations

"This research is focused on dead time and the subsequent count loss estimation in radiation detection systems. The dead time is the minimum amount of time required between two events to permit detection of those events individually by a radiation detection system. If events occur during the system dead time, they are lost. Such lost information can be important in many applications including high-precision spectroscopy, positron emission tomography (PET), and the scanning of spent nuclear fuel. Understanding of the behavior of radiation detection systems is important; thus this work included a comprehensive review of dead time and pulse pile-up models …

Internet-Accessible Hot Cell With Gamma Spectroscopy At The Missouri University Of Science And Technology Research Nuclear Reactor, Edwin Grant

Masters Theses

A dual-chambered internet-accessible heavily shielded facility with pneumatic access to the University of Missouri Science and Technology (Missouri S&T) 200 kW Research Nuclear Reactor (MSTR) core has been built and is currently under low level irradiation testing. The facility allows distance users doing collaborative work with Missouri S&T researchers to manipulate and analyze neutron irradiated samples remotely. The system consists of two shielded compartments, one for multiple sample storage (up to 11 samples), and the other for isolated radiation measurements and spectroscopy. The second chamber has multiple detector ports, graded shielding, and has the capability to support gamma spectroscopy using …

Characterization Of The Neutron Flux Spectrum At The Missouri University Of Science And Technology Research Reactor, Zachary Andrew Kulage

Masters Theses

"A new remotely accessible shielded cell is being constructed at the Missouri University of Science and Technology Research Reactor (MSTR). The heavily shielded cell will be able to receive highly irradiated specimens directly from the reactor and will be equipped with radiation-hardened cameras, remote manipulators and gamma spectroscopy. The cell will allow the manipulation and monitoring of highly activated specimens from both a workstation at the MSTR and at remote locations using a Webbased internet interface. The ability to access and control the shielded cell via a remote internet connection will make it useful to a wide variety of users. …