A model has been developed to predict the long-term
oxidation rate of Zircaloy-4 for ex-reactor (autoclave) and
in-reactor (PWR) environments and operating conditions. A
computer program has been written to solve the oxygen
diffusion equation by employing a fully implicit finite
difference method for a one dimensional cylindrical
geometry. The...
The ion implantation process is a very precise, controllable, and
reproducible method used to enhance material properties of finished
components such as ball bearings. Essentially, the target material is
bombarded by accelerated ions to form a thin alloyed layer in the
substrate. As the ions deposit their kinetic energy in...
Preliminary nuclear design studies have been completed on ten
configurations of nuclear reactors for low power (1-30 kWe) space
applications utilizing thermionic energy conversion. Additional design
studies have been conducted on the TRICE multimegawatt in-core
thermionic reactor configuration. In each of the cases, a reactor
configuration has been determined which...
Conventional stainless steel - water and ceramic fabric composite water
heat pipes have been built and tested. The tests have been conducted to compare
the performance characteristics between conventional and fabric composite heat
pipe radiators for space nuclear power heat rejection systems. The fabric
composite concept combines a strong ceramic...
A rotating, flat plate condensation experiment has been developed to
investigate the heat of the Rotating Bubble Membrane Radiator (RBMR). The
RBMR is a proposed heat rejection system for space applications which uses
working fluid condensation on the inside surface of a rotating sphere to
reject heat to space. The...
A Fabric Composite Radiation Heat Transfer Study has been
conducted to determine the effective emissivities of specific
fabric composite materials. The weave of the fabric and the
high strength capability of the individual fiber in
combination with the thermal conductivity and chemical
stability of specific metallic liner, result in a...
This thesis covers two topics. The first subject
involves tests run on a ultralite reflux tube supplied by
Battelle Pacific Northwest Laboratories (PNL). The second
topic involves tests to determine the relative wicking rates
of several different fabrics.
The ultralite reflux tube supplied by PNL was
constructed of copper and...
Incore thermionic space reactor design concepts which operate at a
nominal power output range of 20 to 50 kWe are described. Details of the
neutronic, thermionic, thermal hydraulics and shielding performance are
presented. Due to the strong absorption of thermal neutrons by natural
tungsten, and the large amount of that...
The design of a fabric composite heat pipe has been completed. It is
composed of two end caps, between which a fluid containment liner composed of
metal foil and an outer structural layer composed of a ceramic fabric is stretched.
The interior of the heat pipe is layered with a...
Lattice bum-up calculations in thermal reactors are complicated by the necessity
for use of transport theory to represent fuel rods, control rods, and burnable absorbers,
by many time-dependent variables which must be considered in the analysis, and by
geometric complexity which introduces time-dependent, spatial-spectral variations.
Representation of lattice structure in...
An overall systems design code was developed to model
an advanced in-core thermionic energy conversion based
nuclear reactor system for space applications at power
levels of 10 to 50 kWe. The purpose of this work was to
provide the overall shell for the systems code and to also
provide the...
A transient code (TFETC) for calculating the temperature
distribution throughout the radial and axial positions of a
thermionic fuel element (TFE) has been successfully developed.
It accommodates the variations of temperatures, thermal power,
electrical power, voltage, and current density throughout the
TFE as a function of time as well as...
Safety concerns at the Hanford Reservation require a way to measure the
moisture content of material contained in the high level radioactive waste tanks. The
freezing of material next to a probe was proposed by scientists at Pacific Northwest
Laboratories (PNL) as one approach to solve this problem. It was...
Five Ultra light Fabric Reflux Tubes (UFRTs) were tested in a thermal vacuum chamber at the National Aeronautics and Space Administration's Johnson Space Center in September 1994. These test articles were design and fabricated by staff at the Pacific Northwest Laboratory, operated by Battelle Memorial Institute for the United States...