The Manufacture of Lead Radiation Bricks their Uses and Nuclead’s Extensive Experience
Lead bricks are mainly used for radiation shielding in high radiation areas such as nuclear reactors and research facilities. In these locations it is typically impractical to use sheet lead due to the high levels of radiation an physical constraints. Lead bricks are usually manufactured in one of two forms, standard square bricks and interlocking lead bricks.
For high radiation areas interlocking lead bricks are often preferred as they allow the surfaces to mate is a way that eliminates any radiation leakage between them. Lead bricks are usually sized 8 or 12 inches long, 4 inches wide and 1 to 2 ½ inches thick.
This article contains information on the use of lead bricks for radiation shielding and Nuclead’s capabilities in this area.
Lead Shielding
Lead is effective for certain types of radiation shielding applications because of its high density and atomic number. Lead is particularly effective for protection against gamma rays and x-rays, since lead has a high atomic number it also has a corresponding high number of electrons. The electrons in lead scatter the photons in the X-rays and Gamma rays. Lead is also effective against alpha particles; these are the same as helium nuclei consisting of 2 protons and 2 neutrons and are a common result of nuclear reactions within a nuclear reactor.
Lead shielding is not effective against beta radiation or other highly charged particle radiation. This type of radiation when impacting on lead shielding can cause bremsstrahlung radiation, which is a form of electromagnetic radiation caused by the deceleration of charges particles.
Lead is also ineffective against neutron radiation, which is one result of nuclear fusion or nuclear fission, this is because neutrons have no charge, and do not significantly interact with the electrons in the lead.
For gammas rays and x-rays the amount of lead shielding needed is a function of the intensity of the radiation. For example lead shielding reduces the intensity of gamma rays and X-rays exponentially, so the thicker the lead the less radiation passes through.
This is one of the reasons why lead bricks are used in shielding for nuclear reactors, where high intensity radiation is often observed. At 4 inches wide, lead bricks are thicker than lead sheets, plus they can be double or triple stacked.
As noted above lead is almost useless for stopping neutrons, materials such as hydrogen have been shown to be better, this is why water is often used as a neutron shield as well as a coolant in nuclear reactors. However a neutron shield can also be a source of gamma rays so lead shielding is used in conjunction with hydrogen when shielding for neutrons.
Lead Bricks
As noted above lead bricks are typically used in reactor radiation shielding because of the high intensity of the radiation produced and lead’s ability to absorb the radiation due to its high atomic number. Lead bricks are also used in certain ship ballast and race handicap applications. Custom lead bricks are used in applications where the lead has to be molded or machined to match the specific application or environment.
Custom lead Bricks are rectangular bricks with machined grooves that allow an inter-locking capability. These interlocking lead bricks can be built up into shielding walls either for temporary or permanent shielding and storage situations. For temporary situations they are easy to stack, un-stack and relocate.
Custom interlocking lead brick systems are ideal for adding additional shielding to existing treatment rooms. Lead brick can also be customized to new construction allowing a reduction in wall or ceiling thickness to achieve space savings.
Often lead bricks will be mounted to steel frames or other structures such as lead lined cabinets and radioactive storage containers for increased structural integrity.In ballast application such as sailing ship ballast and racing car weights, bricks will often be customized to fit the location available. Such as that found in a ship’s keel, bricks can be molded in to specific shapes as required
Manufacture of Lead Bricks
Molds are created as defined by custom blueprints CAD/CAM files, depending on the application the poured lead bricks may consists either lead or alloy. The resulting custom lead bricks are then machined to provide the final finish.
Lead machining requires accurate, repeatable precision. CNC machines are typically used to machine intricate lead designs from standard lead bricks. Custom fabrication may also require the use of saws, mills and lathes to create lead molds or precision lead parts and lead products.
Lead bricks can also be finished using powder coating.
Nuclead’s Lead Bricks
Nuclead can offer any shape or size per customer specifications, including NASCAR racing weights.
Nuclead offers interlocking lead bricks that are tongue and grooved on four edges. The interlocking feature of these lead bricks eliminates any radiation leakage in the wall. These interlocking lead bricks are offered in sizes that are manageable and easy to stack, and they require no mortar or any other additional shielding materials.
Standard available sizes (brick or interlocking lead blocks)
- 1″ x 4″ x 8″ (or 12″)
- 1.5″ x 4″ x 8″ (or 12″)
- 2″ x 4″ x 8″ (or 12″) *most common size
- 2.5″ x 4″ x 8″ (or 12″)
- 3″ x 4″ x 8″ (or 12″)
Lead bricks can also be installed between two rows of studs (with extra steel tube support if required), or between a concrete wall and a row of studs.
Nuclead has supplied lead bricks to a variety of customers including the department of energy, for whom we fabricated custom lead bricks machined and finished, to high tolerance, per specified blue prints that they provided. Another ongoing customer of lead bricks is a state university who ordered several tons of lead bricks manufactured in custom shapes and configured for radiation shielding applications within an underground facility.
Summary
Lead bricks are used in high radiation environments to provide radiation shielding from gamma rays and X-rays as well as other radiation sources.
Lead bricks are also used in certain applications to provide ballast and handicapping.
Nuclead has the experience and expertise to provide any type of custom lead bricks in any quantity required.