How Beryllium is used
Beryllium, a chemical element with the symbol Be and atomic number 4 is a brittle alkaline earth metal that is steel-grey in color and light-weight while exceptionally strong for many industrial uses.
Primarily, it is used as a hardening agent in metal alloys, particularly beryllium copper.
– Mechanical applications
Due to Beryllium’s light weight, stiffness, and stability over a wide temperature range, it is widely used in the defense and aerospace industries for light-weight structural materials in communication satellites and high-speed aircraft, space vehicles and missiles. Many liquid-fueled rockets, including the Saturn V, use nozzles of pure Be.
Beryllium-copper alloys are widely used in many applications because of their high electrical and thermal conductivity, strength and hardness, good corrosion and fatigue resistance, and nonmagnetic properties. These mechanical applications include the making of electrical contacts, springs and non-sparking tools.
Tools made of beryllium are used to tune the highly magnetic klystrons used for high power microwave applications in the telecommunications industry.
Beryllium is also used in the making of computer equipment, watch springs and electrical spring contacts.
The James Webb Space Telescope is being engineered to have 18 hexagonal beryllium sections for its mirrors as beryllium is a material capable of handling extreme cold better than glass. Beryllium contracts and deforms less than glass, thus remaining more uniform in such cold temperatures as the JWST will face. For this same reason, the Spitzer Space Telescope optics are built entirely of beryllium metal.
Beryllium has been utilized in audio loudspeaker construction as an alternative to titanium and aluminium.
In 1968, Porsche employed beryllium brake discs for the 909 hill-climb spyder.
– Radiation-related applications
Beryllium is highly transparent to X-rays, therefore thin sheets of beryllium foil are used as windows in X-ray detectors in order to filter out visible light while allowing only X-rays to be detected.
Sheets of beryllium ranging from 3 millimetres thick down to 25 micrometres thick are used as the output windows in x-ray tubes. This allows x-rays to exit while preserving a vacuum on the inside of the tube.
Beryllium is used for the reproduction of microscopic integrated circuits in the field of X-ray lithography.
Due to its low atomic number, beryllium is almost transparent to electrically charged particles; it is therefore used to build the beam pipe around the collision region in particle physics experiments.
– Nuclear applications
In nuclear weapon designs, beryllium is used as the outermost layer of the pit of the primary stage, surrounding fissile material. It’s the best practical neutron reflector and a good pusher for implosion, reducing critical mass needed for a fission chain reaction. It adds little mass to the weapon while increasing the proportion of fuel that fissions.
Being a light element with few electrons, the fission explosion completely and quickly ionizes the beryllium rendering it transparent to X-rays, thus allowing the energy from a primary fission explosion to escape for the radiation implosion of a secondary fusion stage.
Beryllium has been used in some nuclear reactors. It is a good neutron moderator having a low neutron absorption cross section. Beryllium is currently used in the Joint European Torus fusion research facility and will also be used to condition the plasma-facing components in ITER (a research and development project that aims to demonstrate the scientific and technical feasibility of fusion power).
– Compound applications
Beryllium, an effective p-type dopant in III-V compound semiconductors, is widely used in materials grown by molecular beam epitaxy (MBE). Beryllium oxide is often used for applications requiring the combined properties of an excellent electrical insulator and heat conductor along with high strength and hardness and a very high melting point. In the telecommunications industry, beryllium oxide is often used as an insulator base plate in high-power transistors in RF transmitters. It’s also being considered for use as an agent to increase thermal conductivity of uranium dioxide nuclear fuel pellets.
Beryllium compounds were once used in the manufacturing of fluorescent lighting tubes, however this was discontinued due to the high incident of berylliosis in workers manufacturing the tubes.
– Beryllium hazards
According IARC (the International Agency for Research on Cancer), beryllium and its compounds are Category 1 carcinogens, carcinogenic both to animals and humans. Berylliosis (acute and chronic) is a serious disease caused by exposure to beryllium. Cases of berylliosis affecting workers in plants manufacturing fluorescent lamps in Massachusetts were reported in 1946.
Berylliosis occasionally killed early workers in nuclear weapons design.
In 1949, the use of beryllium compounds in fluorescent lighting tubes was discontinued, yet potential for exposure to beryllium still exists in the aerospace and nuclear industries. Risk of exposure also exists in the melting of beryllium-containing alloys, refining beryllium metal, the manufacturing of electronic devices, and in the general handling of other beryllium-containing materials.
Long term exposure to beryllium is a great health risk. Chronic beryllium disease (CBD) continues to occur in industries such as metal recycling, nuclear weapons production, alloy manufacturing, dental laboratories and defense industries; many metal machine shops work with alloys containing small amounts of beryllium.
This toxic substance can be handled safely if certain procedures are followed – familiarization with correct handling procedures should always be made before ever attempting to work with beryllium.
– Beryllium featured in literature and film for entertainment purposes
In “Galaxy Quest” (a 1999 science fiction comedy film) the protagonists’ spaceship is powered by a “beryllium sphere”.
“Sucker Bait” (a story written by popular science fiction author Isaac Asimov) incorporates the health hazard of beryllium dust as an important plot point.
Reference and further reading:
http://en.wikipedia.org/wiki/Beryllium
http://www.iter.org/
