# pyrk.materials.kernel module¶

class pyrk.materials.kernel.Kernel(name='kernel')[source]

Bases: materials.material.Material

This class represents a material of the system it has material properties essential to thermal modeling and heat transfer in support of calculations related to the thermal hydraulics subblock

density()[source]

Kernel density for TRISO kernel is 10500.0kg/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.

specific_heat_capacity()[source]

Specific heat capacity for TRISO kernel [J/kg/K]

The value 0.3 J/g/K was extracted from Ortensi et al in Figure 11, page 12.

Ortensi, J., and A. M. Ougouag. 2009. “Improved Prediction of the Doppler Effect in TRISO Fuel.” In Proceedings of International Conference on Mathematics, Computational Methods, and Reactor Physics (M&C 2009), Saratoga Springs, NY. http://www.inl.gov/technicalpublications/Documents/4187480.pdf.

Note that a temperature dependent model could be implemented based on that work.

thermal_conductivity()[source]

TRISO Kernel thermal conductivity in [W/m-K]

A first order, constant value approximation was made based on Petti, Martin, Phelip, Fig 1.11

Petti, Martin, Phelip et al http://www.sciencedirect.com/science/article/pii/S0022311510003284#bib9

Note that temperature dependent thermal conductivity model could be implemented in the place of this constant model based on Powers and Wirth: http://www.sciencedirect.com/science/article/pii/S0022311510003284