Materials Library

UO₂

Uranium dioxide at 3 wt% U-235 enrichment. Standard fuel for commercial PWRs and BWRs.

ρ = 10.97 g/cm³

UO₂

Uranium dioxide at 4.5 wt% U-235 enrichment. Common in high-burnup PWR fuel assemblies.

ρ = 10.97 g/cm³

UO₂

Uranium dioxide at 5 wt% U-235 enrichment. Maximum enrichment for standard commercial fuel under current NRC licensing.

ρ = 10.97 g/cm³

UO₂

Uranium dioxide at 19.75 wt% U-235, High-Assay Low-Enriched Uranium. Used in advanced reactor designs and research reactors.

ρ = 10.97 g/cm³

(U,Pu)O₂

Mixed oxide fuel with 5 at% Pu in heavy metal. Depleted U matrix (0.25% U-235) with reactor-grade Pu vector.

ρ = 10.97 g/cm³

UN

Uranium mononitride fuel at 5% U-235 enrichment. High uranium density and thermal conductivity make it attractive for advanced reactors.

ρ = 14.32 g/cm³

UC

Uranium monocarbide fuel at 5% U-235 enrichment. High heavy-metal density and good thermal properties for fast reactor and space reactor applications.

ρ = 13.63 g/cm³

UZrH₁.₆

Uranium-zirconium hydride fuel used in TRIGA research reactors. 20% enriched U with Zr-H matrix providing inherent negative temperature feedback.

ρ = 6 g/cm³

Zirconium alloy cladding used primarily in BWRs. Low neutron absorption cross section with good corrosion resistance.

ρ = 6.56 g/cm³

Zirconium alloy cladding used primarily in PWRs. No nickel content, which improves hydrogen pickup resistance in PWR coolant chemistry.

ρ = 6.56 g/cm³

Austenitic stainless steel widely used for reactor structural components, piping, and vessel internals.

ρ = 7.94 g/cm³

Molybdenum-bearing austenitic stainless steel with improved corrosion resistance. Used in fast reactor cladding, PWR internals, and hot-leg piping.

ρ = 7.99 g/cm³

Nickel-chromium superalloy used in reactor vessel head penetrations, springs, and high-temperature structural components.

ρ = 8.19 g/cm³

Nickel-molybdenum alloy developed for molten salt compatibility. Primary structural material for the MSRE and proposed MSR designs.

ρ = 8.86 g/cm³

Plain carbon steel used for reactor pressure vessel construction (with SS cladding), structural supports, and containment liner.

ρ = 7.82 g/cm³

H₂O

Light water at room temperature (~20°C). Primary moderator and coolant in PWRs and BWRs.

ρ = 0.998 g/cm³

D₂O

Deuterium oxide at room temperature. Moderator and coolant in CANDU and other heavy-water reactors, providing superior neutron economy.

ρ = 1.105 g/cm³

C

Nuclear-grade graphite moderator. Used in gas-cooled reactors (AGR, HTGR), RBMK, and molten salt reactors.

ρ = 1.7 g/cm³

Be

Beryllium metal used as a neutron reflector and moderator in research and test reactors. Excellent neutron economy due to (n,2n) reactions.

ρ = 1.85 g/cm³

BeO

Beryllium oxide (beryllia) used as a moderator and reflector in compact reactors. Higher density than graphite with excellent thermal conductivity.

ρ = 3.01 g/cm³

Li₂BeF₄

Lithium fluoride–beryllium fluoride molten salt (2LiF-BeF₂). Primary coolant/fuel carrier for fluoride-salt-cooled and molten salt reactors. Li-7 enriched to 99.995% to minimize tritium production.

ρ = 1.94 g/cm³

LiF-NaF-KF

Lithium fluoride–sodium fluoride–potassium fluoride eutectic salt (46.5-11.5-42.0 mol%). Used as a secondary coolant and heat-transfer fluid in MSR designs.

ρ = 2.09 g/cm³

Na

Liquid sodium coolant at ~100°C. Primary coolant in sodium-cooled fast reactors (SFRs) such as EBR-II, BN-600/800, and proposed designs like Natrium.

ρ = 0.968 g/cm³

Pb

Natural lead coolant. Used in lead-cooled fast reactors (LFRs) for its high boiling point, good neutron economy, and shielding properties.

ρ = 11.35 g/cm³

Pb-Bi

Lead-bismuth eutectic (44.5% Pb, 55.5% Bi by weight). Low melting point (~125°C) liquid metal coolant for fast reactors and spallation targets.

ρ = 10.17 g/cm³

CO₂

Carbon dioxide gas at STP. Coolant in gas-cooled reactors (Magnox, AGR) and supercritical CO₂ Brayton cycle power conversion.

ρ = 0.00184 g/cm³

He

Helium gas at STP. Coolant in high-temperature gas-cooled reactors (HTGR, VHTR) and fuel-cladding gap fill gas.

ρ = 0.000164 g/cm³

Standard Portland cement concrete. Primary biological shielding material in reactor facilities. Composition from PNNL-15870.

ρ = 2.3 g/cm³

High-density concrete using baryte (BaSO₄) aggregate. Enhanced gamma-ray shielding compared to ordinary concrete due to high-Z barium content.

ρ = 3.35 g/cm³

(CH₂)ₙ + 5% B

Polyethylene loaded with 5 wt% natural boron. Combined neutron moderation (H) and thermal neutron capture (B-10) for effective neutron shielding.

ρ = 0.95 g/cm³

(CH₂)ₙ

High-density polyethylene (HDPE). Effective neutron moderator and shield due to high hydrogen content.

ρ = 0.93 g/cm³

B₄C

Boron carbide with natural boron (19.9% B-10). Control rod and burnable absorber material. B-10 has a large thermal neutron absorption cross section (3840 barns).

ρ = 2.52 g/cm³

B₄C

Boron carbide enriched to 90% B-10. Used in control rods and shielding where maximum neutron absorption per unit volume is needed.

ρ = 2.52 g/cm³

Ag-In-Cd

Silver-indium-cadmium alloy (80-15-5 wt%). Standard control rod absorber material in PWRs, providing absorption across a wide energy range.

ρ = 10.17 g/cm³

Gd₂O₃

Gadolinium oxide burnable absorber. Gd-155 and Gd-157 have the largest thermal neutron capture cross sections of any stable nuclides (~61,000 and ~254,000 barns).

ρ = 7.41 g/cm³

Hf

Hafnium metal control rod absorber. All stable Hf isotopes have significant absorption cross sections, providing long control rod lifetime without depletion concerns.

ρ = 13.31 g/cm³

Eu₂O₃

Europium oxide used as a burnable poison and control material. Eu-151 has a very large thermal neutron absorption cross section (~9,200 barns).

ρ = 7.42 g/cm³

Dry air at standard temperature and pressure (20°C, 1 atm). Used for streaming calculations, room modeling, and atmospheric transport.

ρ = 0.001205 g/cm³

Ar

Argon gas at STP. Cover gas in sodium-cooled fast reactors to prevent sodium-air reactions.

ρ = 0.001662 g/cm³

N₂

Nitrogen gas at STP. Used for inerting containment and fuel handling areas.

ρ = 0.001165 g/cm³

Vacuum or void region. No material is present; particles stream freely through these regions.

ρ = 0 g/cm³