Europium Oxide

Eu₂O₃

Absorbers

Density: 7.42 g/cm³

Atom density: 0.0634851 atoms/b·cm

Europia control and burnable absorber material, used in Russian reactor designs and in research reactor control elements.

Where these numbers come from

Eu₂O₃ stoichiometry with natural europium (abundances from the compendium's europium-doped entries). Density carried over from the previous NRDP entry; the oxide is not in the compendium.

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)
O-16 (8016)	1.3602e-1	5.9854e-1	3.7998e-2
O-17 (8017)	5.5065e-5	2.2800e-4	1.4475e-5
O-18 (8018)	3.1454e-4	1.2300e-3	7.8087e-5
Eu-151 (63151)	4.1006e-1	1.9124e-1	1.2141e-2
Eu-153 (63153)	4.5356e-1	2.0876e-1	1.3253e-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.

What ENDF/B-VII.1 forced

O18 folded into O16: ENDF/B-VII.1 has no O18 evaluation (3.1454e-4 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

MCNP

c Europium Oxide
c ReactorMC NRDP derived material - reactormc.net/nrdp/material/eu2o3; rho =
c 7.42 g/cm3 (use -7.42 on the cell card)
c O18 folded into O16: ENDF/B-VII.1 has no O18 evaluation (3.1454e-4 by weight,
c so the spectrum does not care).
m37    8016.80c  -0.136332  $ O16
       8017.80c  -5.5065e-5  $ O17
       63151.80c  -0.410056  $ Eu151
       63153.80c  -0.453558  $ Eu153

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

Eu-151 is about 9,200 barns thermal. Its capture product Eu-152 is radioactive (13.5 y) and a strong gamma emitter, so europium absorbers add to spent-fuel handling dose.

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