Custom Job


Small Mix Kit

On-site casting is sometimes the only way to achieve the  desired shielding. Our castable shielding products can be used to fill walls, surround spent fuel and withstand enormous pressures and temperatures.

Boron-Silicone is a fire-resistant, heat-resistant, field-castable elastomer with a high hydrogen content (67% of water's). It is self-extinguishing and will withstand temperatures up to 400° F (205° C) for extended periods while retaining 90% of its hydrogen. Boron-Silicone contains 1% boron for thermal neutron capture and the suppression of capture-gammas.

Other boron concentrations can be supplied upon request.

SWX-237-0 Poly-Substitute is a boron free version of the standard silicone elastomer mix, boasting the same physical properties, including the high hydrogen content and self-extinguishing nature.  It is frequently used when fire and temperature restrictions prevent the use of HDPE.

Although this is a solid material, its resiliency will minimize any impact due to secondary missile formation.  Its density is 1.59 g/cc (99 lbs./cu ft).

Boron-Silicone is available in a variety of shapes and sizes.  For example, Shieldwerx has provided large pre-cast rings for use as a biological neuron shield for coolant recalculating lines.  The material has also been used in the manufacture of

large fuel transportation and as reactor cavity shield

plugs where the customer cast 9,000 pounds of the material, on-site, for use as a sacrificial shield.  Another customer cast the Silicone Mix into shipping containers for spent fuel storage.

View Catalogue Sheet 237

View Catalogue Sheet 237-0

Kretekast Samples

Kretekast Samples

High temperature resistance is a frequent requirement for power reactor shielding.  Kretekast is a refractory material designed to retain a significant portion of its shielding properties at temperature up to 450°F (230°C).  This material will maintain its physical integrity at temperatures up to 1900°F (1038°C).  In addition, this rugged material is completely non-combustible and can be easily cast in the field.  Its compressive strength is 1000 psi (90 BAR).

Kretekast is well suited to attenuate the neutron flux from power reactors by the inclusion of hydrogen and boron in the forms of temperature-resistant additives.  It incorporates approximately three times as much hydrogen as ordinary concrete, making the material far superior for neutron shielding applications.  The hydrogen concentration - which moderates fast neutrons - is approximately one-half that of water.  The refractory matrix also provides good resistance to heat.

Standard Kretekast has a boron content of 1.6% and type 277Z-5 contains 5%.  It is also available in other concentrations of boron or can be made to be boron-free and used as a poly-substitute.

Type 277 is offered in the form of dry mix for casting in place, but can also be supplied in pre-cast shapes.  Customers often use 277 in the ES-3100 storage casts.  It is readily shaped with ordinary concrete-strength power tools (e.g., band saws or drills).  Kretekast Dry Mix is available in 300 pound (136kg) drums.

View Catalogue Sheet


Quantities Required to Cast One Cubic Foot:


     Type      Dry Mix

      237        99 lbs

      259        56 lbs

      277        96 lbs

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Rio Rancho, NM 87124

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