from utilities.ur import units
from materials.material import Material
from density_model import DensityModel
[docs]class Graphite(Material):
"""This class represents graphite materials. It inherits from the material
class and has attributes intrinsic to graphite.
"""
def __init__(self, name="graphite"):
"""Initalizes a material
:param name: The name of the material (i.e., "fuel" or "cool")
:type name: str.
"""
Material.__init__(self,
name=name,
k=self.thermal_conductivity(),
cp=self.specific_heat_capacity(),
dm=self.density())
[docs] def thermal_conductivity(self):
"""
Graphite thermal conductivity in [W/m-K]
For H451 nuclear grade graphite:
Parallel to forming axis:
150 W/m-K
Perpendicular to forming axis:
135 W/m-K
Burchell, T.D. 2001. ''Nuclear Graphite and Radiation Effects.'' In
Encyclopedia of Materials: Science and Technology (Second Edition),
edited by K.H. Jurgen Buschow, Robert W. Cahn, Merton C. Flemings,
Bernhard Ilschner, Edward J. Kramer, Subhash Mahajan, and Patrick
Veyssiere, 6310-19. Oxford: Elsevier.
http://www.sciencedirect.com/science/article/pii/B0080431526011207
Also noted in:
http://www.osti.gov/scitech/servlets/purl/714896/
"""
return 0.26*units.watt/(units.meter*units.kelvin)
[docs] def specific_heat_capacity(self):
"""Specific heat capacity for H451 graphite [J/kg/K]
For H451 Graphite, the specific heat capacity at normal operating
temperatures for this reactor is approximately 1650 [J/kg/K]
The temperature dependent model arrived at in Ortensi et al is :
.. math::
c_p &= (0.54212\\\\
&- (2.42667E-06)\\times T\\\\
&- (9.02725E+01)\\times T^{-1}\\\\
&- (4.34493E+04)\\times T^{-2}\\\\
&+ (1.59309E+07)\\times T^{-3}\\\\
&- (1.43688E+09)\\times T^{-4}\\times 4184\\\\
Ortensi, J., M. A. Pope, G. Strydom, R. S. Sen, M. D. DeHart, H.
D. Gougar, C. Ellis, et al. 2011. ''Prismatic Core Coupled
Transient Benchmark.'' Transactions of the American Nuclear Society
104: 854.
"""
return 1650.0*units.joule/(units.kg*units.kelvin)
[docs] def density(self):
"""
Graphite density for H451 nuclear grade graphite is 1740kg/m^3.
A constant density model appears sufficiently accurate according to
most sources - Andreades et al in particular:
Andreades, C., A.T. Cisneros, J.K. Choi, A.Y.K Chong, David L.
Krumwiede, Lakshana Huddar, Kathryn D. Huff, et al. 2014. Technical
Description of the Mark 1 Pebble-Bed, Fluoride-Salt-Cooled,
High-Temperature Reactor Power Plant. Thermal Hydraulics Group
UCBTH-14-002. FHR Project. Berkeley, CA: University of California,
Berkeley, Department of Nuclear Engineering.
Note that in the dissertation by M. Fratoni, this number is reported as
"1.74 kg/m^3". However, this is a units error. The number intended by
that document was 1.74 g/cm^3, which corresponds to this model.
"""
return DensityModel(a=1740.*units.kg/(units.meter**3),
model="constant")