Hydrogen Isotopes - Deuterium and Tritium

Fusion is the process by which nuclei fuse at very high temperatures to form a larger nucleus. The commonest process is the fusion of hydrogen isotopes (deuterium and tritium) to form helium. These weapons are also referred to as hydrogen bombs (for obvious reasons) and their power is measured in megatons (1 megaton = 1 000 000 tons TNT). 

Other studies on Nb-based membranes have been developed and proposed for the separation of hydrogen isotopes (deuterium and tritium) from He in the fuel cycle of fusion reactors. As mentioned in previous sections. 

The only other particles that appear to tunnel atomic distances with chemical energies are hydrogen and its isotopes, deuterium and tritium. Because these particles... 

Fusion is what powers the Sun and stars. One type of fusion reaction involves the combination of two "heavy" isotopes of hydrogen. Isotopes of an element have the same number of protons, but a different number of neutrons. For example, hydrogen and its isotopes—deuterium and tritium—all have one proton in their nuclei. Remember that the number of protons plus the number of neutrons make up the mass of an atom. Because they have different numbers of neutrons, hydrogen, deuterium, and tritium have different masses. Deuterium has one proton and one neutron. It has a mass of 2 atomic mass units (amu). Deuterium can also be written as hydrogen-2. The number following the element s name is the isotope s mass. Tritium has one proton and two neutrons. So, tritium has a mass of 3 amu. Tritium can be written as hydrogen-3. 

The deuteron and triton are the nuclei of two isotopes of hydrogen, called deuterium and tritium. Deuterium occurs naturally in water. When the D2O is purified as heavy water, it can be used for several types of chemical analysis. 

Particles with the same atomic number Z, but different numbers of neutrons are called isotopes. Deuterium and tritium are isotopes of hydrogen, as they all have the same atomic number, Z = 1, but different numbers of neutrons, namely, 0,1 and 2, respectively, and have different mass numbers of 1, 2 and 3, respectively. While the mass numbers are integer, the atomic weights are not necessarily integer if more than one isotope of an element occurs naturally. Thus, Cl (atomic weight = 35.46)... 

You are to study kinetic parameters of nucleotide incorporation in a growing nucleic acid chain. Which of the hydrogen isotopes - deuterium or tritium - will you use and why ... 

Figure 2.15 The three isotopes of hydrogen protium, deuterium and tritium... 

D 1. Write a chemical symbol with mass number A and atomic number Z for the three isotopes of hydrogen protium, deuterium and tritium ... 

The ordinary isotope of hydrogen, H, is known as Protium, the other two isotopes are Deuterium (a proton and a neutron) and Tritium (a protron and two neutrons). Hydrogen is the only element whose isotopes have been given different names. Deuterium and Tritium are both used as fuel in nuclear fusion reactors. One atom of Deuterium is found in about 6000 ordinary hydrogen atoms. 

Tables 2,3, and 4 outline many of the physical and thermodynamic properties ofpara- and normal hydrogen in the sohd, hquid, and gaseous states, respectively. Extensive tabulations of all the thermodynamic and transport properties hsted in these tables from the triple point to 3000 K and at 0.01—100 MPa (1—14,500 psi) are available (5,39). Additional properties, including accommodation coefficients, thermal diffusivity, virial coefficients, index of refraction, Joule-Thorns on coefficients, Prandti numbers, vapor pressures, infrared absorption, and heat transfer and thermal transpiration parameters are also available (5,40). Thermodynamic properties for hydrogen at 300—20,000 K and 10 Pa to 10.4 MPa (lO " -103 atm) (41) and transport properties at 1,000—30,000 K and 0.1—3.0 MPa (1—30 atm) (42) have been compiled. Enthalpy—entropy tabulations for hydrogen over the range 3—100,000 K and 0.001—101.3 MPa (0.01—1000 atm) have been made (43). Many physical properties for the other isotopes of hydrogen (deuterium and tritium) have also been compiled (44).

Pulsed plasmas containing hydrogen isotopes can produce bursts of alpha particles and neutrons as a consequence of nuclear reactions. The neutrons are useful for radiation-effects testing and for other materials research. A dense plasma focus filled with deuterium at low pressure has produced 10 neutrons in a single pulse (76) (see Deuterium AND TRITIUM). Intense neutron fluxes also are expected from thermonuclear fusion research devices employing either magnetic or inertial confinement. 

Thermodynamic Properties. Ordinary water contains three isotopes of hydrogen [1333-74-0] (qv), ie, H, H, and H, and three of oxygen [7782 4-7] (qv), ie, O, and The bulk of water is composed of and O. Tritium [15086-10-9] H, and are present only in extremely minute concentrations, but there is about 200-ppm deuterium [16873-17-9], H, and 1000-ppm in water and steam (see Deuterium and tritium). The thermodynamic properties of heavy water are subtly different from those of ordinary water. lAPWS has special formulations for heavy water. The properties given herein are for ordinary water having the usual mix of isotopes. 

Isotopic Exchange Reactions. Exchange reactions between the isotopes of hydrogen are well known and well substantiated. The equihbrium constants for exchange between the various hydrogen molecular species have been documented (18). Kinetics of the radiation-induced exchange reactions of hydrogen, deuterium, and tritium have been critically and authoritatively reviewed (31). The reaction T2 + H2 — 2HT equiUbrates at room temperature even without a catalyst (30). 

It IS often stated that unclear fusion tvill produce no radioactive hazard, but this is not correct. The most likely fuels for a fusion reactor would be deuterium and radioactive tritium, which arc isotopes of hydrogen. Tritium is a gas, and in the event of a leak it could easily be released into the surrounding environment. The fusion of deuterium and tritium produces neutrons, which would also make the reactor building itself somewhat radioactive. However, the radioactivity produced in a fusion reactor would be much shorter-lived than that from a fission reactor. Although the thermonuclear weapons (that use nuclear fusion), first developed in the 1950s provided the impetus for tremendous worldwide research into nuclear fusion, the science and technology required to control a fusion reaction and develop a commercial fusion reactor are probably still decades away. 

Only the isotopes of hydrogen have their own names deuterium and tritium. "Naked" hydrogen, the proton, catalyzes many important reactions. 

Hydrogen The first chemical element in the periodic table. It has the atomic symbol H, atomic number 1, and atomic weight 1. It exists, under normal conditions, as a colorless, odorless, tasteless, diatomic gas. Hydrogen ions are protons. Besides the common HI isotope, hydrogen exists as the stable isotope deuterium and the unstable, radioactive isotope tritium. [NIH]... 

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