RESEARCH PERFORMED AT THE UNIVERSITY OF TENNESSEE
Title: High Power Target Studies, 2003-2004, DOE.
High amplitude shock waves are caused by the sudden deposit of thermal energy from the proton beam pulse in high power spallation neutron sources. These shocks are part of the reason for moving to liquid metal targets for these systems. The shocks still pose a challenge to the pressure boundary constraining the liquid metal. The shocks also cause cavitation at the interface between the liquid metal and the pressure boundary. Studies are performed of the efficacy of introducing a 0.005 volume fraction of helium to the mercury in the form of 30 micron diameter bubbles. This adds compressibility to the liquid and greatly lowers the shock amplitudes. The impact of this technique on the fluid delivery system during normal operation and anticipated transients is evaluated.
Title: Fluorine 18 Target Optimization, 2001-2003, CTI, inc.
Isotope production for Positron Emission Tomography (PET) is currently accomplished
using cyclotrons producing 11 MeV protons. The protons bombard targets with
oxygen 18 feedstock to produce fluorine 18. Water enriched with oxygen 18 is
a favorite target material. The short half-life of the Fluorine 18 encourages
rapid production and distribution cycles. The expense of the Oxygen 18 motivates
high conversion rates and small target inventories. The research focused on
maximizing the beam power deposited per unit target mass while maintaining pressures
and temperatures at levels acceptable to conventional beam window materials.
Title: Pressurized Water Reactor Hot Leg Thermal Striping: 1992-1994, NRC Grant
Some of the conventional pressurized water reactor (PWR) designs (e.g., Westinghouse inverted Top-Hat designs) have complex spatial temperature fields in the hot legs. This phenomenon makes the measurement of the hot leg bulk temperature difficult and introduces error in the energy balance for the primary coolant flow. The US-NRC has sponsored an experimental and theoretical investigation of methods for accurately measuring the bulk temperature in existing PWR hot legs. This research involves extensive temperature field and thermal mixing measurements in a three-inch diameter flow field with velocities up to 8 m/s. Thermal mixing models are used to predict and augment the temperature field data and to bound the bulk temperature measurement error. The parameters in the turbulent mixing models are verified with hot wire measurements.
Title: Boron Transport in the AP-600: 1993-1995, Westinghouse Electric Co.
The transport of Boron injected into the cooling water of the core region of the Westinghouse AP-600 (pressurized water reactor) was evaluated experimentally and numerically to verify emergency shutdown response.
Title: Low Mass Flow Thermal Limits: 1994-1995, United States National Academy of Sciences
Thermal limits during boiling with low time average mass flow and during unsteady flow were examined and the influence of heater thermal characteristics was established.
Title: Subcooled Boiling Pressure Drop in the Advanced Neutron Source Reactor: 1993-1995, Martin Marietta Energy Systems
Subcooled Boiling Pressure Drop in the core cooling of the Advanced Neutron Source Reactor is accomplished with forced convection of subcooled water. The water velocity is 27 m/s and the subcooling is 122 Celsius allowing thermal flux values in the neighborhood of 10 MW per square meter. Models for subcooled boiling pressure drop were developed to allow accurate simulation of the reactor response during transients. Modeling efforts were coordinated with experiments at ORNL used to generate data to validate models.
Title: Scaled Boiling Water Reactor (BWR): 1993-1997, TVA
A low pressure working reactor model (i.e., electrical heaters for nuclear fuel) with clear pressure boundaries was developed to facilitate student laboratory activities and short courses for reactor operators. The model helped the Nuclear Engineering Department recover from the loss of access to reactors at the Oak Ridge National Laboratory for student training. A vapor volume fraction measurement technique was developed to facilitate the simulation of void reactivity feedback in the model that is of use in other research and industrial activities. The model includes a see-through working turbine, developed as a student design project.
Title: Liquid Lithium Jet Stability Studies: 1995-1996, Lockheed Martin Energy Systems
The stability of a jet of liquid Lithium was investigated experimentally and theoretically. The jet flowed over a concave back plate at 17 m/s and served as the target for a proton beam in a facility designed to produce high energy Neutrons. A fluid dynamic examination of the free surface of the jet identified dimensionless parameters important to the jet behavior. These parameters were used to construct a scaled experimental facility to verify the findings of the theoretical evaluation.
Title: Mercury Stock Propagation and Cavitation Studies: 1996-1998, Lockheed Martin Energy Systems
A Mercury target is used for a proton beam in the current design for a Spallation Neutron Source in development at the Oak Ridge National Laboratory. Basic theoretical and experimental studies were performed to establish conditions for the incipience of cavitation in the Mercury. Interaction of hot molten metal and subcooled water were also investigated.
Title: Predictive Maintenance Initiative at the High Flux Isotope Reactor (HFIR): 1998-1999, Lockheed Martin Energy Research
Methods for predictive maintenance were implemented for 40 critical components at the HFIR. Metrics for evaluation of performance in the maintenance organization were developed to allow continuous improvement of maintenance operations.
Title: Fluid Flow Scaling and Uncertainties in Results of Experiments Supporting the Spallation Neutron Source (SNS) Target Development, 1998-2000, Lockheed Martin Energy Research
Verification of design parameters in the liquid Mercury SNS target is not possible in a completely prototypic experiment. Scaled experiments in water and air are employed to examine the thermo-fluid behavior of the SNS target and uncertainties associated with using these techniques are developed. Data interpretation and reduction activities were also conducted for a Mercury heat transfer experiment supporting SNS target design.
Title: Leak Rate Modeling and Leak Detection in Vacuum Systems with Water Jackets
Leak rates were investigated as a function of leak size for leaks between a helium saturated water jacket and a vacuum. Several flow-modeling strategies were required, including single-phase viscous flow, two phase flashing viscous flow, and two phase critical flow, single-phase gas compressible flow and molecular flow. All flows were in micro-channels. The leak rate simulations were joined with performance specifications for conventional helium detection equipment to establish the feasibility of using helium dissolved in water as a leak detection strategy.
RESEARCH PERFORMED AT THE OAK RIDGE NATIONAL LABORATORY (ORNL), 1988-1992
Title: Counter-Current Flow Limited (CCFL) Heat Flux in the High Flux Isotope Reactor (HFIR)
A full scale HFIR fuel assembly was used to establish the CCFL performance of the reactor and to establish the CCFL heat flux. A theoretical model was developed utilizing conservation principles and interfacial drag laws for annular film flows to predict the data. This work supported the revised safety analysis report for the HFIR.
A Heavy Water New Production Reactor (HWNPR) was being developed by the Department of Energy (DOE) from 1989 to 1992. Served on the HWNPR thermal-hydraulic technical working group as the ORNL representative. The group consisted of representatives from the DOE laboratories and from academe. This group provided technical review and policy/strategy recommendations to DOE during the HWNPR development.
Title: Interfacial Drag Models for Research Reactor Fuel Cooling Channels
A simple single channel experiment was conducted to evaluate interfacial drag models appropriate to narrow rectangular channels. Image processing techniques were employed to measure the liquid fraction in the channel. The data were compared to other data and models in the literature.
Title: Inlet Flow Blockage Evaluation for the Advanced Neutron Source Reactor (ANSR) Fuel Assembly
A facility was developed to establish the maximum allowable size of inlet flow blockage the ANSR could incur without fuel damage. This facility employed a thermochromic film on the back of a heater strip to allow spatial temperature measurement using image processing techniques. The spatial temperature field was converted to spatial variation in heat transfer coefficient to establish if the cooling was adequate to prevent fuel damage. ORNL researchers completed the facility in 1993 and produced remarkable data on the distribution of the heat transfer coefficient downstream of inlet flow blockages.
Two commendations for technical contributions to the High Flux Isotope Reactor (HFIR) and the Advanced Neutron Source Reactor (ANSR) were awarded during the time spent at the Oak Ridge National Laboratory.
RESEARCH PERFORMED AT RENSSELAER
Ph.D. research examined pressure wave propagation in bubbly air water flows and used data from these investigations to establish models for interfacial momentum transfer that facilitate well-posed two-fluid simulations.
Several research projects were performed as a project manager at the Center for Manufacturing Productivity at Rensselaer. Reports from these efforts were company confidential and student theses were subject to review by the sponsor and sanitized of business sensitive information. Some brief representative descriptions of this work follows:
Automated Sheet Metal Die Finishing, General Motors
A Cartesian robot was used with several end-effectors to modify surface properties on a sheet metal die from those present after machining to those required for service.
Automated Wafer Cleaning and Drying, IBM
Several techniques were explored to automate cleaning of polishing slurry from wafers prior to their introduction to the process line. A single technique was identified as best suited to the task and a working prototype of an automated wafer cleaner and dryer using this technique was delivered.
Precision Level Sensors, Anderson Instruments
A level/pressure measurement device was developed capable of stable pressure measurement with precision of less than one part in one thousand. Hysteresis free materials and drift free, temperature compensated electronics were required.
Automated Printed Wire Board Lamination, IBM
A robotic assembly cell was developed to assemble large sheets (24" x 30") of printed wire into multi-laminate stacks with registration tolerances of less than 0.0005 inches. A two-tiered, two-dimensional optical position feedback control system was developed for the system.
INTERNATIONAL COLLABORATION
Worked with Dr. Alexander Vasiliev from the Nuclear Safety Institute in Moscow for one year under the sponsorship of the U. S. National Academy of Science. This collaboration resulted in publications important to predicting thermal limits during unsteady flows.
Worked with Mr. Yuemin Zhou from Chengdu, China, for nine months. Mr. Zhou is currently in charge of thermal-hydraulic R&D for an Advanced Pressurized Water Reactor, AC-600.
Developed vapor generation models for micro-scale channels with French researcher, Maite Lopez, as part of an exchange program coordinated with the CEA in France.