PolyCast Neutron Shield

JC259 & JC259Z-4

JC259 & JC259Z-4 are a field-castable dry mix that provides excellent neutron shielding characteristics. 

It is typically cast into closed containers and retains its hydrogen content even at elevated temperatures. JC259 contains 0.9% boron. For better thermal neutron attenuation JC259Z-4 contains 4% boron. 

JC259 is mixed on-site with water and provides a hydrogen atom density that is roughly 6% greater than that of pure water.  While the recommended temperature limit for JC259 is 150 °F (66 °C), it will retain about 80% of its hydrogen content up to 300 °F (140 °C).

JC259 can be poured in layers and each layer forms a solid bond with the one underneath.  It requires approximately 56lbs. of JC259 dry mix to produce 1 ft³ of cast material.  The material is typically provided in fibre barrels weighing 165lbs (net).

  • Excellent neutron shielding with 0.9% to 4% boron additive
  • Field-castable into closed containers
  • Maintains 80% of its very high hydrogen content up to 300°F
  • Uses include, walls, back filling and roof slabs for cyclotron facilities
  • Sets up in about 30 minutes, requires only mixing with water
Composition Data (as cast): JC259 JC259Z-4
Hydrogen atom density / cm³: 7.15 x 10²² 6.98 x 10²²
Hydrogen weight percent: 10.40% 10.10%
Boron atom density / cm³: 5.82 x 10²⁰ 2.57 x 10²¹
Boron natural isotope distribution: 19.6% ¹⁰B and 80.4% ¹¹B 19.6% ¹⁰B and 80.4% ¹¹B
Boron weight percent: 0.91% 4.00%
Total Density: 1.15g/cm³ (72 lbs/ft³) 1.15g/cm³ (72 lbs/ft³)
Radiation Properties
Macroscopic thermal neutron cross section: 0.46 (cm⁻¹) 1.96 (cm⁻¹)
Gamma resistance: 5x10⁸ rad 5x10⁸ rad
Neutron resistance: 2.5x10¹⁷ n/cm² 2.5x10¹⁷ n/cm²
Physical Properties
State: Solid composite with pellets Solid composite with pellets
Colour: White White
Odour: No odour No odour
Machinability: Poor Poor
Compressive Strength: Poor Poor
Thermal Properties
Recommended Temperature Limit: 150°F (66°C) 150°F (66°C)
Chemical Properties
Chemical Name & Synonyms: Borated hydrogenated mix Borated hydrogenated mix
Trade Name & Synonyms: JC259 Polykast JC259Z-4 Polykast
Chemical Family: Ca salt, B, polyolefins Ca salt, B, polyolefins
Solubility in Water: <1% (cast) <1% (cast)
Reactivity Data
Reactive Metals and Metal Compounds: Aluminium
Material Incompatibility
Materials to Avoid: Water, potassium and acetic anhydride.
Not compatible with aluminium housings
Gas: C, CO, CO₂, H₂O, organic vapours
Hazardous Polymerisation: Will Not Occur
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