Ag-In-Cd Control Rod

Ag-In-Cd

Absorbers

Density: 10.17 g/cm³

Atom density: 0.0561523 atoms/b·cm

Silver–indium–cadmium alloy, the standard PWR control rod absorber. Absorbs across a wide energy range instead of relying on one resonance.

Where these numbers come from

The standard PWR control rod alloy, 80-15-5 wt% Ag-In-Cd, with each element expanded over its natural isotopes. Density carried over from the previous NRDP entry; the alloy 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)
Ag-107 (47107)	4.1471e-1	4.2311e-1	2.3759e-2
Ag-109 (47109)	3.8529e-1	3.8587e-1	2.1668e-2
Cd-106 (48106)	6.2500e-4	6.4367e-4	3.6143e-5
Cd-108 (48108)	4.4500e-4	4.4981e-4	2.5258e-5
Cd-110 (48110)	6.2450e-3	6.1977e-3	3.4801e-4
Cd-111 (48111)	6.4000e-3	6.2941e-3	3.5343e-4
Cd-112 (48112)	1.2065e-2	1.1760e-2	6.6033e-4
Cd-113 (48113)	6.1100e-3	5.9025e-3	3.3144e-4
Cd-114 (48114)	1.4365e-2	1.3755e-2	7.7240e-4
Cd-116 (48116)	3.7450e-3	3.5242e-3	1.9789e-4
In-113 (49113)	6.4350e-3	6.2165e-3	3.4907e-4
In-115 (49115)	1.4356e-1	1.3628e-1	7.6522e-3

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 Ag-In-Cd Control Rod
c ReactorMC NRDP derived material - reactormc.net/nrdp/material/ag-in-cd; rho =
c 10.17 g/cm3 (use -10.17 on the cell card)
m34    47107.80c  -0.414712  $ Ag107
       47109.80c  -0.385288  $ Ag109
       48106.80c  -6.2500e-4  $ Cd106
       48108.80c  -4.4500e-4  $ Cd108
       48110.80c  -0.006245  $ Cd110
       48111.80c  -0.006400  $ Cd111
       48112.80c  -0.012065  $ Cd112
       48113.80c  -0.006110  $ Cd113
       48114.80c  -0.014365  $ Cd114
       48116.80c  -0.003745  $ Cd116
       49113.80c  -0.006435  $ In113
       49115.80c  -0.143565  $ In115

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

The three metals cover different energies: cadmium cuts off sharply at 0.5 eV, indium has a strong 1.46 eV resonance, and silver absorbs through the epithermal range. Together they give a rod worth that changes little as the spectrum hardens.

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