Heavy water
A heavy water ice sink to the bottom of a beaker filled with H2O due its neutrons weight
Heavy water is the common term for water which includes the deuterium isotope of hydrogen as D2O or DHO. The deuterium in heavy water is much the same as normal hydrogen, which is also known as protium, except that it contains an extra neutron. So a deuterium atom contains one neutron, one proton, and one electron. Heavy water was discovered by Urey (1932).
Heavy water(D2O) occurs naturally but very less when compared to normal water molecules, about one in twenty–million water molecules are heavy water molecules. Human body contains few grams of heavy water as natural abundance.
A heavy water plant
Heavy water is most known for its role in regulating the processes of nuclear reactors that don't use enriched uranium. As nuclear reactors engage in fission, they release neutrons. These neutrons move incredibly quickly. In order to have a more controlled chain reaction with un–enriched uranium, the neutrons need to be slowed down. So to do that, a regulator of some sort is used. Beryllium, graphite and normal water are all used as regulators and all have their own benefits and limitations. Heavy water is another regulator, with the added neutron making it more stable to regulate neutrons passing through it.
Heavy water isn't really created, as such, but it is refined. At industrial levels heavy water is obtained by electrolysis of Normal Water. Hundreds of liters of normal water under continued electrolysis used to produce a few milliliters of pure deuterium oxide, hydrogen gas is released at cathode in this process. This method(Electrolysis) has been replaced by less expensive fractional distillation method, as deuterium oxide is less volatile than H2O, it gets concentrated in liquid residue, thus D2O is obtained.
Deuterium used in thermonuclear weapons
Applications:
- Heavy water is used as a moderator of neutrons in nuclear power plants.
- Deuterium is used in thermonuclear weapons for fusion reactions, produces massive energy.
- In the laboratory heavy water is used as an isotopic tracer in studies of chemical and biochemical reaction process.
- It is used as a solvent in nuclear magnetic resonance spectroscopy method.
- Deuterium is used for isotopic labeling of organic compounds(such as C–H bond replaced by C–D).
- Small quantities of it(D2O)is used in treatment of infants, lactating women and adults without any reported adverse effect.
- Heavy water is toxic when its presence exceeds 20% in Body fluids.