Patent Number: H00004464
Section: summary

BACKGROUND OF THE INVENTION This invention relates to a method of controlling the reaction rates in a nuclear fusion reactor; and more particularly, to the use of polarized nuclear fuel. In order to make fusion easier to achieve, the interacting nuclei should have the smallest positive charge (i.e. lowest atomic number). Since hydrogen (H) and its isotopes deuterium (D) and tritium (T) all have the lowest atomic number and since hydrogen and deuterium are virtually unlimited in supply, the hydrogen isotopes are thought to be most suitable for a fusion reactor. The basic fusion reactions involving the hydrogen isotopes are: EQU D+D.fwdarw.He.sup.3 +n (1) EQU D+D.fwdarw.T+H (2) EQU D+T.fwdarw.He.sup.4 +n (3) EQU D+He.sup.3 .fwdarw.He.sup.4 +H (4) Studies of the probabilities or nuclear cross sections of these reactions indicate that reaction (3) has been found to take place most readily. It has also been found that reactions (1) and (2) take place at about the same rate. Reaction (2) is important because it means that tritium would not have to be supplied from an outside source (i.e. bred from the exotic fuel, lithium). Reactions (1) and (3) produce large numbers of high energy neutrons which are not available for use for ignition. Reaction (3) also produces large numbers of alpha particles which have to be contained. Control of the hydrogen isotope reaction rates would permit greater flexibility in the design and operation of a controlled fusion reactor. Therefore, it is an object of the present invention to control the various reaction rates in a nuclear fusion reactor. It is a further object of the present invention to enhance or suppress the various reaction rates in a nuclear fusion reactor. Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. SUMMARY OF THE INVENTION Although it has been known that nuclear reaction rates are dependent on the polarization of the reactant nuclei, it was erroneously believed that various processes occuring in a fusion reactor would depolarize the reactant nuclei. The inventors have demonstrated (A detailed analysis appears in R. M. Kulsrud et al "Fusion Reactor Plasmas with Polarized Nuclei" presented at 9th International Conference on Controlled Nuclear Fusion Research, Sept. 1-8, 1982) that four processes that produce depolarization in a reactor: inhomogeneous fields, collisions, magnetic fluctuations which operate on the nuclei when they are in the reactor, and the atomic processes (recombination, chargeexchange and ionization), which operate during the injection phase or in a tokamak during the recycling phase produce depolarization rates that are so small that polarization in a reactor delay be maintainable at close to one hundred percent. In accordance with the foregoing, a method of controlling the reaction rates of the fuel atoms in a controlled fusion reactor having a plasma confining magnetic field may comprise the step of polarizing the nuclei of the fuel atoms in a particular direction relative to the plasma confining magnetic field. Improved nuclear fuel for use in a controlled fusion reactor having a plasma confining magnetic field may comprise fuel atoms whose nuclei are polarized in a particular direction relative to the plasma confining magnetic field. The use of polarized fuel atoms produces a plasma of polarized nuclei. There are a number of practical advantages to be gained from the use of a polarized plasma in a fusion reactor. The nuclear reaction rates can be increased or decreased, and the direction of emission of the reaction products can be controlled.