Poly-based Shielding

5% Borated Polyethylene
SWX-201

Sizing: 1” to 6” thick, up to 48" x 48", plus rods up to 9" diameter

A polyethylene composite of 5% boron is widely used in neutron shielding applications because of its excellent nuclear and physical characteristics. Type 201 is lightweight and easily moved for temporary shielding. It is especially useful in shielding against low and intermediate neutron energies - recommended limit is 180° F (82° C). Type 201 shows excellent attenuation of thermal neutrons and significant reduction of capture-gamma dose. Fast neutrons are moderated by the high concentration of hydrogen atoms (96% that of water).

Another important advantage of type 201 is its low cost. Type 201 is available in a variety of shapes, including sheets, bricks, and rods. It is easily shaped and cut using ordinary woodworking tools. For special applications, it may be desirable to use boron loadings other than 5%. Shieldwerx can custom manufacture boron-polyethylene with other boron levels. Please contact one of our shielding experts for further information on these special order materials.

See Catalogue Sheet

5% Borated Polyethylene - High Density
SWX-201HD

Sizing: 1” & 2” up to 48" x 96" plus pellets

For more physically demanding applications, our 5% Borated Poly was expanded to include a high density version of 201. This material has all the properties of 201, but is more than 10% denser with better shielding and mechanical characteristics.

As an alternative to machining the material in your own shops, our experienced staff can supply the material to your specifications. Standard shapes include sheets, bricks, and pellets.

This borated polyethylene material has been used at research and test reactors to shield personnel and equipment for neutron radiography and other specialized experiments, for shielding of large neutron beam line, in the vicinity of research accelerators, and in hot cells and glove boxes that contain neutron sources.

See Catalogue Sheet

1% Self-Extinguishing Borated Polyethylene
SWX-207HD

Sizing: 1” thick up to 48" x 96"

Self-Extinguishing borated polyethylene has a slightly lower hydrogen content than type 201, and is used for similar applications when flame resistance is a major consideration. It is also a high density shielding material.

Self-extinguishing materials are highly desirable in power reactor environments where there is concern about materials that might add to the general level of combustible materials (fire loading). ASTM Test D-635, Flammability of Self-Supporting Plastics, shows the material to be self-extinguishing. ASTM Test D-2863 gives a Limiting Oxygen Index of 30.2. In addition to fire resistance, type 207 produces negligible amounts of smoke when expose to flame.

Type 207HD is optimized for higher energy neutron moderation with 1% boron for thermal attenuation. Its density of 1.6 g/cc (100 lbs./cu ft), relatively high for polyethylene based material, contributes to gamma shielding.

See Catalogue Sheet

5% Self-Extinguishing Borated Polyethylene
SWX-207HD5

Sizing: 1” thick up to 48" x 96"

Our self-extinguishing line was expanded to include a 5% version of 207HD. This material has similar properties to the 207HD with better thermal neutron attenuation due to the higher boron content.

Type 207HD5 is used in nuclear power plants for shielding hatches, ducts, sumps, and stairwells and/or other applications where fire safety is a concern.

See Catalogue Sheet

30% Boron Polyethylene
SWX-210

Sizing: 1” to 6” thick, up to 48" x 48", plus rods up to 9" diameter

Criticality control is important in many all phases of fuel handling and reprocessing. In order to assure neutron isolation, materials containing very high concentrations of boron are frequently used.

Type 210 consists of polyethylene loaded with 30% natural boron. It is a very effective thermal neutron poison. It also has significant hydrogen content for higher energy moderation. Type 210 is available in sheets, bricks, and rods. It can also be manufactured with other Boron loadings.

See Catalogue Sheet

Pure Polyethylene
SWX-213

Sizing: 1” and 2” thick up to 48" x 96", rods up to 6" diameter and pellets

Pure polyethylene (HDPE) is frequently used as a moderator where it is desired to slow fast neutrons to thermal energies. In these applications it is highly desirable to maximize the hydrogen content and HDPE provides a very high hydrogen atom density.

We can supply high purity polyethylene in a variety of shapes and sizes including sheets, bricks, rods, and pellets for filling irregular spaces. Pure polyethylene can be readily machined into complex shapes for applications involving reactor physics, activation analysis, isotopic neutron sources and specialty fabricated neutron casks.

See Catalogue Sheet

7.5% Lithium Polyethylene
SWX-215

Sizing: 1” to 6” thick, up to 48" x 48", plus rods up to 9" diameter

Gamma-sensitive radiation detectors used in the vicinity of neutron sources must generally be shielded to minimize the background due to neutron interactions. Use of borated polyethylene as a shield can attenuate the neutron flux, but the neutrons captured by the boron will result in a secondary gammas and can add to the gamma background.

7.5% Lithium-Polyethylene is very effective in reducing the detector background gammas because it produces no capture gammas. Thus, when used to shield a gamma detector from neutrons, it eliminates the usual capture-gamma background. Its lower capture cross-section means that lithium is less effective than boron for capturing thermal neutrons and therefore requires a greater thickness than borated polyethylene.

This material can be supplied as cylinders, or as sheets or bricks for building up your own detector shield. All lithium compounds used in our shielding contain the natural isotopic distribution of lithium. Shields using customer-supplied enriched lithium-6 have been manufactured for special applications.

See Catalogue Sheet

Poly-Biz Gamma Shield
SWX-217

SWX-217 Poly-Biz is an environmentally friendly alternative to lead-based shielding products. It is comprised of a solid suspension of high density bismuth powder in a polyethylene matrix. Poly-Biz is a non-hazardous gamma shield with an additional benefit of neutron moderation.

1-inch of Poly-Biz is roughly equivalent to 1/4-inch of lead for gamma shielding applications. Poly-Biz is typically provided as slabs or bricks, but is readily machined into custom shapes.

Sizes: Custom slabs and cylinders

See Catalogue Sheet