Glossary letter B

Background Radioactivity

There are three general categories of natural radioactivity on Earth: the radioactivity of unstable elements created at the same time as the Earth (primordial); radioactivity resulting directly from cosmic rays; and the radioactivity of radionuclides produced by cosmic rays in the upper atmosphere. The level of naturally occurring radioactivity, which varies depending on location, is not hazardous to health.



Tiny living organisms that are made up of a single cell that does not have a distinct nucleus, such as a prokaryotic cell. Due to their ability to colonize even the most extreme environments, bacteria are all around us. Some bacteria (germs, or microbes) are harmful to human beings and can trigger disease, but other bacteria — such as those found in the intestine that aid digestion — are beneficial.



Unit of volume measurement for crude oil that is equivalent to approximately 159 liters (0.159 cubic meters). The barrel was introduced as the standard unit of measurement by American and U.K. oil companies. Its origin stems from the wooden barrels used to ship whiskey, salt and herring to the United States and, at one time, crude oil.

Barrel of Oil Equivalent (boe)

Unit of measurement used to convert an energy content into its equivalent in volume of oil. It is widely used to standardize the energy content of oil deposits, which always contain some gas.


Bathymetry is the study of the topography of the seabed and ocean floors. Bathymetric readings are used to map water depths in order to provide a visual presentation of seafloor terrain in the form of bathymetric charts.


A monocyclic aromatic hydrocarbon with the molecular formula C6H6. It is a key precursor for a number of organic compounds, such as plastics, solvents, detergents, colorants, drugs, food additives, fragrances, explosives and pesticides.


A light liquid fraction obtained when bituminous coal undergoes pyrolysis (a process also known as coking in the iron and steel industry, where it is used primarily to produce coke, a base component in the manufacture of cast iron and steel). Benzol is made up of benzene, toluene and all three xylene isomers, all of which are important intermediates in the manufacture of numerous derivatives, in particular polystyrenes and polyamides (benzene), polyurethane (toluene), and polyethylene terephthalate (PET) plastic and polyesters (paraxylene).

Bioclimatic Architecture

Design intended to optimize the comfort of people living or working in a building while reducing its environmental impact. It focuses on indoor temperature control, indoor air quality and natural lighting in rooms.


A substance capable of being decomposed by naturally occurring fungi and microorganisms.


Biofuel obtained by converting plant or animal oils, such as rapeseed, sunflower or used cooking oil. Commonly referred to as diester in Europe and North America. It can be used in existing diesel engines when blended into conventional diesel in concentrations of 7 to 30%. It is made up of fatty acid methyl esters (FAME), sometimes also known as vegetable oil methyl esters (VOME). At present, biodiesel is derived from the reaction of vegetable oil with methanol. Research is currently focused on oils that could be produced by microorganisms such as bacteria, yeast strains and microalgae.


Refers to the natural diversity of living organisms. It can be measured through the study of species, genes and ecosystems.


A fuel produced from plant or animal matter. There are currently two types of biofuel: biodiesel, manufactured from oil-rich plants like rapeseed, oil palm and soybeans; and bioethanol, based on fermenting sugar derived from plants like sugarcane, corn, sugar beet and wheat. Research is currently focused on developing advanced biofuels derived from the inedible parts of plants. This would reduce competition between food crops and the transportation sector.



A product of the methanation (anaerobic digestion) of organic waste. Biogas contains 50 to 70% methane (CH4, identical to natural gas), 20 to 50% carbon dioxide and small amounts of ammonia, nitrogen and hydrogen sulfide, which means that it needs to be treated before it can be used as a fuel.



In the energy sector, biomass is defined as all organic matter of plant or animal origin, including municipal solid waste and agricultural and industrial waste. Biomass is converted into energy through combustion, methanation or other chemical conversion processes.


Refers to two types of material: 1) Plastic derived from renewable resources, such as corn, wheat, sweet potato, sugarcane or castor oil; and 2) Plastic designed to biodegrade, some of which is derived from petrochemicals. Therefore, not all bioplastics are biodegradable or derived from renewable resources.

Blue Energy

Energy produced using renewable resources from the marine environment (tides, currents, waves, wind, biomass, or temperature or salinity differentials). The term is also used occasionally to describe nuclear fusion.


Boron is a metalloid, semi-conducting chemical element (symbol B). It is most widely used in detergents (sodium perborate) and the manufacture of glass fibers (borax). Boron is also used in electronic components, especially in photovoltaic cells as a doping agent for silicon.


Brent is the name given to a relatively light crude oil made from a blend of crudes from 19 oil fields in the North Sea. Brent Crude is one of the three main benchmarks for crude oil prices per barrel, along with West Texas Intermediate (WTI) from North America and Dubai Crude from the Persian Gulf. Brent is also the name of an oil field located in the North Sea off the coast of Scotland, which was discovered in 1971 and started production in 1976. Brent is an acronym for Broom, Rannoch, Etive, Ness and Tarbert – the five geological formations that form the Middle Jurassic field.

Bundle (Nuclear)

See Fuel Assembly.


Butene, also known as butylene, is an alkene with four carbon atoms (formula C4H8). Like all alkenes, butene contains a carbon-carbon double bond, which means that it can be used to make polymers. Butene is an intermediate product in the synthesis of isoprene and manufacture of adhesives. It is also used in the production of MTBE fuels and to increase fuel octane ratings.