Popular Science News: The abundance and purity of boron-10 acid - the "twin codes" in the field of nuclear energy

In the fields of nuclear reactor safety protection and cancer treatment, a compound called "boron-10 acid" is quietly playing a key role. However, the two indicators surrounding it, "abundance" and "purity", often confuse the public. What is the difference between the two? Why do scientists treat them as strictly as "carving diamonds"? This article will reveal this scientific mystery.

1. Isotope abundance: Boron-10's "rarity" competition

Boron is not a "single child" in nature, but coexists in two isotope forms: boron-10 (¹⁰B) and boron-11 (¹¹B) , with natural abundances of about 19.1% and 80.9% respectively. The two have almost the same chemical properties, but their nuclear properties are very different - boron-10 has a strong "swallowing" ability for neutrons and is a core component of nuclear reactor control rods and radiation protection materials.

Isotopic Abundance refers specifically to the proportion of boron-10 in the total boron element. For example, the boron-10 abundance of natural boric acid is 19.1%, while nuclear-grade boron-10 acid must be concentrated to more than 96% by gas centrifugation or chemical exchange . For every 1% increase in abundance, its neutron absorption efficiency may increase exponentially, which can be called "the first gate of nuclear energy safety."

2. Chemical purity: the “fatal trap” of impurities

If abundance is a competition of "quality", chemical purity is a competition of "cleanliness". It measures the content of non-boron substances (such as metal ions, organic matter, and other acids) in boric acid (H₃BO₃). For example, the purity of reagent-grade boric acid can reach 99.999%, while that of industrial-grade boric acid may only be 99%.

In boron neutron capture therapy (BNCT), insufficiently pure boric acid containing heavy metal impurities may poison the patient's cells; in semiconductor manufacturing, excessive sodium ions will directly lead to chip performance degradation. Therefore, High Purity Needs to rely on fine processes such asrecrystallization and ion exchange to achieve.

3. Abundance and purity: why are both indispensable?

1. Nuclear power plant control rods

* High abundance : ensures rapid absorption of neutrons to prevent runaway chain reactions.
* High purity : prevent impurities (such as chloride ions) from corroding the metal cladding and causing leakage accidents.

2. Bio -targeted cancer therapy (BNCT)

* High abundance : Increases the probability of boron-10 capturing neutrons and accurately kills cancer cells.
* High purity : eliminate toxic impurities and protect healthy tissues.

3. Semiconductor doping process

* Specific abundance : Adjusting the boron-10/11 ratio can change the conductivity characteristics of silicon crystals.
* Ultra-high purity : A single speck of dust can destroy an entire wafer.

4. Breaking through bottlenecks: China’s “double breakthrough” in technology

For a long time, high-abundance boric acid-10 has been monopolized by Europe and the United States, with prices as high as hundreds of dollars per gram. In recent years, China has increased the abundance to more than 99% through laser isotope separation technology , and used supercritical fluid purification to control impurities at the ppb (parts per billion) level. In 2023, China National Nuclear Corporation announced that it has achieved independent mass production of kilogram-level high-abundance and high-purity boric acid-10 , reducing costs by 90%, paving the way for the localization of fourth-generation nuclear power plants and BNCT equipment.

Conclusion: “Precision Warfare” in the Microscopic World

From isotope abundance to chemical purity, the "double standard challenge" of boric acid-10 reflects humanity's ultimate pursuit of material manipulation. At the atomic and molecular scale, every 0.1% improvement may rewrite the fate of an industry. In the future, with the rise of fields such as quantum computing and nuclear fusion, this "precision war" will only intensify. In this war, every gram of effort by scientists is lighting up new possibilities for human civilization.