Carbon Dioxide
CO₂
Moderators & CoolantsDensity: 0.00184212 g/cm³
Atom density: 0.000075 atoms/b·cm
Carbon dioxide at room conditions — coolant in Magnox and AGR reactors, and the working fluid of supercritical CO₂ power cycles.
Where these numbers come from
PNNL-15870 Rev. 2, "Carbon Dioxide" (id carbon-dioxide): 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) | 2.6975e-1 | 3.2977e-1 | 2.4937e-5 |
| C-13 (6013) | 3.1615e-3 | 3.5667e-3 | 2.6972e-7 |
| O-16 (8016) | 7.2512e-1 | 6.6505e-1 | 5.0292e-5 |
| O-17 (8017) | 2.9356e-4 | 2.5333e-4 | 1.9157e-8 |
| O-18 (8018) | 1.6768e-3 | 1.3667e-3 | 1.0335e-7 |
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.
What ENDF/B-VII.1 forced
- O18 folded into O16: ENDF/B-VII.1 has no O18 evaluation (0.001677 by weight, so the spectrum does not care).
The cards keep the material's mass and atom count; a nuclide the library cannot name hands its share to one it can. That is why a card row can differ slightly from the table above.
Generated material cards
c Carbon Dioxide
c PNNL-15870 Rev. 2, "Carbon Dioxide" - reactormc.net/nrdp/material/co2; rho =
c 0.00184212 g/cm3 (use -0.00184212 on the cell card)
c O18 folded into O16: ENDF/B-VII.1 has no O18 evaluation (0.001677 by weight,
c so the spectrum does not care).
m26 6000.80c -0.272910 $ C
8016.80c -0.726797 $ O16
8017.80c -2.9356e-4 $ O17MCNP 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
The compendium density is at 1 atm. An AGR runs CO₂ at ~4 MPa and 650 °C, and an sCO₂ cycle at 200–500 kg/m³ — two to three orders of magnitude denser than this card. Scale it.