Uranium Carbide

Fuels

Density: 13.63 g/cm³

Atom density: 0.065674 atoms/b·cm

Uranium monocarbide at 3 wt% U-235. High heavy-metal density and good thermal properties for fast and space reactor fuel.

Where these numbers come from

PNNL-15870 Rev. 2, "Uranium Carbide" (id uranium-carbide): density and full isotopic composition are taken from the compendium unchanged.

Open the compendium entry for the isotope-by-isotope table and the compendium's own notes.

Material compositions from PNNL-15870 Rev. 2 (April 2021), R.S. Detwiler, R.J. McConn Jr., T.F. Grimes, S.A. Upton, and E.J. Engel, Compendium of Material Composition Data for Radiation Transport Modeling, Pacific Northwest National Laboratory. Full report (DOI 10.2172/1782721)

Composition

Nuclide (ZAID)	Weight fraction	Atom fraction	Atom density (atoms/b·cm)
C-12 (6012)	4.7492e-2	4.9465e-1	3.2486e-2
C-13 (6013)	5.5661e-4	5.3500e-3	3.5135e-4
U-234 (92234)	2.5417e-4	1.3573e-4	8.9142e-6
U-235 (92235)	2.8559e-2	1.5186e-2	9.9732e-4
U-236 (92236)	1.3137e-4	6.9559e-5	4.5682e-6
U-238 (92238)	9.2301e-1	4.8461e-1	3.1826e-2

This is the material as formulated. The cards below carry weight fractions, written negative, which is what MCNP and Serpent read as a mass basis.

Generated material cards

MCNP

c Uranium Carbide
c PNNL-15870 Rev. 2, "Uranium Carbide" - reactormc.net/nrdp/material/uc; rho =
c 13.63 g/cm3 (use -13.63 on the cell card)
m7    6000.80c  -0.048048  $ C
      92234.80c  -2.5417e-4  $ U234
      92235.80c  -0.028559  $ U235
      92236.80c  -1.3137e-4  $ U236
      92238.80c  -0.923007  $ U238

MCNP and Serpent cards use .80c (ENDF/B-VII.1 at 293.6 K) — renumber m1 and change the suffix to match your deck. SCONE compositions are atom densities in atoms/barn-cm with the .03 suffix matching temp 300. See the library reference before changing a suffix: the mapping is not portable between vendors.

Notes

Carbon is written as elemental 6000 because ENDF/B-VII.1 has exactly one elemental evaluation and carbon is it — there is no 6012.80c. On ENDF/B-VIII.0 (`.00c`) the rule inverts: C-12 and C-13 exist and 6000 does not.

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