Beryllium

Moderators & Coolants

Density: 1.848 g/cm³

Atom density: 0.123487 atoms/b·cm

Beryllium metal reflector and moderator for research and test reactors. Excellent neutron economy, and Be-9(n,2n) makes it a multiplier as well as a reflector.

Where these numbers come from

PNNL-15870 Rev. 2, "Beryllium" (id beryllium): 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)
Be-9 (4009)	1.0000e+0	1.0000e+0	1.2349e-1

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.

Bound scattering

ENDF/B-VII.1 has a thermal scattering law for this material as formulated, so the cards attach be-met.20t. Free-gas scattering would misplace the thermal spectrum here.

Generated material cards

MCNP

c Beryllium
c PNNL-15870 Rev. 2, "Beryllium" - reactormc.net/nrdp/material/beryllium; rho =
c 1.848 g/cm3 (use -1.848 on the cell card)
m19    4009.80c  -1.000000  $ Be9
mt19   be-met.20t

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

Beryllium is toxic as a dust; handling is a controlled operation. The card attaches be-met.20t for bound scattering in the metal lattice.

← Back to Materials Library