Carbon Steel (AISI 1045)

Cladding & Structural

Density: 7.872 g/cm³

Atom density: 0.08651 atoms/b·cm

Plain medium-carbon steel, for structural supports, containment liner, and shielding geometry where the exact alloy does not matter.

Where these numbers come from

PNNL-15870 Rev. 2, "Steel, Medium Carbon (1045)" (id steel-medium-carbon-1045): 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)	4.9421e-3	2.2569e-2	1.9524e-3
C-13 (6013)	5.7922e-5	2.4410e-4	2.1117e-5
Mn-55 (25055)	9.0000e-3	8.9772e-3	7.7661e-4
P-31 (15031)	4.0000e-4	7.0768e-4	6.1221e-5
S-32 (16032)	4.7354e-4	8.1162e-4	7.0213e-5
S-33 (16033)	3.8557e-6	6.4082e-6	5.5437e-7
S-34 (16034)	2.2509e-5	3.6313e-5	3.1414e-6
S-36 (16036)	5.6080e-8	8.5443e-8	7.3916e-9
Fe-54 (26054)	5.5614e-2	5.6501e-2	4.8878e-3
Fe-56 (26056)	9.0532e-1	8.8694e-1	7.6729e-2
Fe-57 (26057)	2.1282e-2	2.0483e-2	1.7720e-3
Fe-58 (26058)	2.8819e-3	2.7259e-3	2.3582e-4

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 Carbon Steel (AISI 1045)
c PNNL-15870 Rev. 2, "Steel, Medium Carbon (1045)" -
c reactormc.net/nrdp/material/carbon-steel; rho = 7.872 g/cm3 (use -7.872 on the
c cell card)
m15    6000.80c  -0.005000  $ C
       25055.80c  -0.009000  $ Mn55
       15031.80c  -4.0000e-4  $ P31
       16032.80c  -4.7354e-4  $ S32
       16033.80c  -3.8557e-6  $ S33
       16034.80c  -2.2509e-5  $ S34
       16036.80c  -5.6080e-8  $ S36
       26054.80c  -0.055614  $ Fe54
       26056.80c  -0.905324  $ Fe56
       26057.80c  -0.021282  $ Fe57
       26058.80c  -0.002882  $ Fe58

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

This is not a pressure-vessel steel. RPV plate and forgings (SA-533 Grade B, SA-508) carry ~0.2 wt% carbon plus nickel, molybdenum and chromium, and the nickel content drives embrittlement and activation — model those with their own composition. The old entry claimed to be ASTM A516 Grade 70 while carrying 0.5 wt% carbon, which is roughly double that specification's ceiling and matches 1045 instead.

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