JC277 and 277Z-5 are excellent high flux neutron shields due to the inclusion of temperature resistant additives that provide hydrogen for moderation and boron for thermal neutron absorption. It provides more than twice the hydrogen of ordinary concrete (equal to approximately ½ that of pure water) along with a boron content of 1.6% and 5% respectively.
Power reactor and other industrial neutron shielding applications often require a material that exhibits a high-temperature resistance. Kretekast is a refractory material that retains its shielding properties at temperatures up to 450°F (230 °C) and its physical integrity up to 1900°F (1038 °C). It is entirely non-combustible and is designed to be cast in the field.
JC277 is provided as a dry mix for casting in the field. It can be shaped using standard concrete cutting/drilling tools. Kretekast is typically provided in 300lb fibre barrels.
Approximately 96lbs. of dry mix are required to obtain one-cubic ft. of cast material. (1.54 kg of dry mix will give one litre). Detailed mixing instructions are provided with each order. Recommended shelf-life under dry storage conditions is twelve months.
Features at a glance
- Contains more than two times as much hydrogen as ordinary concrete along with 1.6% to 5% boron additives
- Rugged “concrete-like” shielding is easily cast in the field
- Low cost material is completely non-combustible
|Hydrogen atom density / cm³:||4.93 x 10²²||4.76 x 10²²|
|Hydrogen Weight Percent:||4.90%||4.73%|
|Boron atom density / cm³:||1.53 x 10²¹||4.67 x 10²¹|
|Boron Natural isotope distribution:||19.6% ¹⁰B and 80.4 % ¹¹B||19.6% ¹⁰B and 80.4 % ¹¹B|
|Boron weight percent:||1.63%||4.99%|
|Total Density:||1.68 g/cm³ (105 lbs./ft³)||1.68 g/cm³ (105 lbs./ft³)|
|Macroscopic thermal neutron cross section:||1.17 cm⁻¹||3.54 cm⁻¹|
|Gamma resistance:||1 x 10¹¹ rad||1 x 10¹¹ rad|
|Neutron resistance:||5 x 10¹⁹ n/cm²||5 x 10¹⁹ n/cm²|
|State:||Solid composite||Solid composite|
|Colour:||Light grey||Light gray|
|Odour:||No odour||No odour|
|Machinability:||Fair: saw cut or drilled||Fair: saw cut or drilled|
|Tensile Strength (ASTM D368):||100 psi||100 psi|
|Compressive Strength:||1000 psi||1000 psi|
|Recommended Temperature Limit:||176°C (350°F)||176°C (350°F)|
|Coefficient of thermal conductivity:||1.24 x 10⁻³ cal-cm/sec-cm²-°C||1.24 x 10⁻³ cal-cm/sec-cm²-°C|
|(0.3 BTU-ft/hr-ft²-°F)||(0.3 BTU-ft/hr-ft²-°F)|
|Heat Capacity:||0.22 cal/g-°C||0.22 cal/g-°C|
|Cubical Coefficient of Expansion:||8 x 10⁻⁶ cm³/cm³-°C||8 x 10⁻⁶ cm³/cm³-°C|
|(1.4 x 10⁻⁵ in³ /in³ -°F)||(1.4 x 10⁻⁵ in³ /in³ -°F)|
|Chemical Name & Synonyms:||Borated hydrogenated mix||Borated hydrogenated mix|
|Trade Name & Synonyms:||JC277 Kretekast||JC277Z-5 Kretekast Plus|
|Chemical Family:||Calcium salts, boron, hydrogen compounds||Calcium salts, boron, hydrogen compounds|
|Solubility in Water:||Negligible||Negligible|