Boron in Nuclear Energy


Borates play a key role in the operation of nuclear power plants, and they are essential in the safety and control of pressurized water reactors (PWRs) and boiling water reactors. The 10B isotope, present at around 20% natural abundance, has a very high nuclear cross section and can capture the thermal neutrons that result from the fission reaction of uranium nuclear fuel. This radiation-absorbing effect is used in the shielding, control, and safety of nuclear reactors and in medical therapeutics.

Boron and nuclear reactors
Some newer reactor technologies don’t need borates to circulate through the reactor core. Yet, borates are still used for emergency shutdown systems, control rods, and shielding.
Pressurised water reactors

Borates in PWRs

By dissolving high-purity boric acid in the primary cooling circuit of PWRs, operators can adjust the quantity of 10B in the reaction environment—and thus control the rate of a nuclear reaction and the energy that it generates. In some scenarios, borates can also be used in the secondary circuit as a corrosion inhibitor.

Nuclear control rods can be made of boron carbide, an extremely hard ceramic. Borates can be used in the cooling water in fuel storage pools. And borates serve as a key safety feature of emergency core-cooling systems, where they are injected into the core from the tank. Consistent boron levels maintain a consistent energy output; out-of-control reactions can be quenched with boric acid, which absorbs neutrons. Sodium borates are also used as corrosion inhibitors.

Boron and Nuclear Energy

Borates in boiling water reactors

Borates are not used in the cooling circuit of boiling water reactors. As in PWRs, control rods made of boron carbide may be used, and borates can be used in fuel storage pools. Borated water is used in the standby liquid control system tank, and borates can be injected into the core as a last measure in emergency conditions.

Boron neutron capture therapy (BNCT) is an experimental treatment for cancers and other diseases in which neutron capture is harnessed to perform effective microsurgery. 

20 Mule Team Borax Products

These 20 Mule Team® Borax products are developed for use in nuclear energy.

Optibor boric acid

From reducing melting temperatures in fiberglass production to inhibiting corrosion in fuel additives, Optibor has a multitude of uses in numerous industries. Learn More

Potassium Tetraborate

An excellent buffering agent, potassium tetraborate can lower the pH of strong alkalis and is also used in welding, soldering, and brazing fluxes. Learn More

Sodium Pentaborate

Used primarily in oilfield drilling, sodium pentaborate provides lubrication and stabilization in wells and downhole drilling. Learn More


When it comes to particulate materials, particle size affects end product quality and properties. U.S. Borax offers many of its products in powder grade. Learn More

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U.S. Borax, part of Rio Tinto, is a global leader in the supply and science of borates—naturally-occurring minerals containing boron and other elements. We are 1,000 people serving 500 customers with more than 1,700 delivery locations globally. We supply 30% of the world’s need for refined borates from our world-class mine in Boron, California, about 100 miles northeast of Los Angeles.  Learn more about Rio Tinto.

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