This class provides for patents directed to processes involving induced nuclear reactions and structures which implement such processes.
(1) Note. For purposes of classification in this class, an induced nuclear reaction is defined as a change in the nucleus of an atom brought about by subjecting it (the nucleus) to (a) an impact with other nuclei of the same or different type, or (b) an impact with, or bombardment by, subatomic particles or high energy electromagnetic radiations.
(2) Note. Reactions of type (a) in (1) Note, above, include those which cause or result in the combining or uniting of at least two nuclei to form a different nucleus which reactions are generally referred to as fusion reactions. Reactions of type (b) in (1) Note, above, include (1) those which cause a splitting or subdivision of the nucleus (usually a heavy nucleus) into a plurality of different nuclei and are generally referred to as fission reactions, and (2) those which result in a single but different nucleus of the same or a different element and are generally referred to as transmutations.
(3) Note. A basis for placing a patent into this class is that a nuclear reactor be claimed or that it be utilized to obtain a nuclear reaction even though the sole or primary aim of the patent in regard to the reactor is to obtain useful nuclear energy or to utilize such nuclear energy yielding system for conversion into other forms of useful energy or power. This is true even though from a chemical view there may be nothing novel, or from an economical view, nothing of
value, with respect to the products or materials resulting from the nuclear reaction.
(4) Note. Patents to processes are not segregated from patents to the structure, but are classified together depending upon the type of structure claimed or used in the claimed process.
Included within the scope of the class are patents directed to (a) the nuclear reactor as a system of elements or parts so interrelated as to produce induced nuclear reactions and to (b) such elements or parts, per se, as are essential and peculiar components of nuclear reactors. Included among (a), for example, are neutron detectors wherein the detection takes place by means of an induced nuclear reaction. Included among (b), for example, are fuel element structures (including fuel "targets" or "pellets"), control component structures, moderator component structures, fuel element storage structures, and refueling machines.
LINES WITH OTHER CLASSES
Also included in this class are the following (see Subclass References to the Current Class, below, for subclass references): (1) Note. Patents to processes or apparatus including a step or means for (a) converting the nucleus of a substance other than the reactor fuel to a nucleus of another substance, (b) treating or irradiating of material, or (c) making a material radioactive, all within such reactor, including for such purposes as the production of nuclear fuel or experimentation, study or research, etc.
(2) Note. Patents to processes or apparatus including a step or means for converting the nucleus of a substance or for making a substance radioactive by bombardment with accelerated particles from a source other than a nuclear reactor.
(3) Note. Patents directed to combination of a process or apparatus under the class definition with a step or means, e.g., (a) of cooling or heat exchange even though the purpose is to generate steam for extraneous uses, or (b) with a step or means for carrying out of a chemical reaction, etc.
(4) Note. Patents to processes or apparatus including an arrangement of steps or means for amplifying neutrons of a subcritical mass to controllable fission reaction levels, i.e., subcritical reactors.
(5) Note. Patents to all devices, structures, and processes for irradiating a nucleus with its antinucleus (e.g., protonantproton) so as to produce annihilation radiation, i.e., induced matter-antimatter reaction.
(6) Note. Patents to processes or devices that utilize a
gaseous or light element fuel material, the particles of which are electrically charged or excited to the point where they become highly ionized and the forces of repulsion of like nuclei is overcome, or substantially so, wherein it is the intent of the patent that this be the result of such ionization, to the end that nuclear fusion of such like nuclei is obtained or sought to be obtained.
Reactor structure in combination with any other art device is classified in this class.
(1) Note. The line between the subject matter of this class and those classes utilizing nuclear energy reactors or reactions in an ancillary fashion for such purposes as the production of power either electrical or mechanical and for similar purposes is as follows: this class provides for claimed apparatus and processes wherein the reactor or reaction is recited either specifically or broadly and wherein structure utilizing the reactor or reaction, e.g., motor, generator, ship, aircraft, etc., is recited either specifically or broadly.
(2) Note. Patents to processes utilizing nuclear energy to bring about chemical reactions between either inorganic or organic compounds in order to provide a different compound or product, provided neither reactor structure nor a nuclear reaction is claimed are classified elsewhere (see References to Other classes, below). Class 376, however, takes such patents if some reactor structure is claimed or if the resulting compound or product is either claimed, or is disclosed as being radioactive.
(3) Note. This class also provides for patents to all processes and to certain devices or structures for irradiating a substance of a subject specimen or sample for research and related purposes or for making such substance radioactive. This holds true however only if the irradiation produces a transformation or similar modification of the nucleus of the substance, or if the treatment makes the substance radioactive. For other types of irradiation, see References to Other classes, below.
(4) Note. Elements and subcombinations of nuclear reactors which may, if recited in general terms, be provided for elsewhere, are classified in this class if recited in terms of the subject matter of this class. (5) Note. A process of utilizing nuclear energy to bring about chemical reactions that treat or prepare a synthetic resin or rubber, provided neither nuclear reactor structure nor a nuclear reaction is claimed, is elsewhere (see References to Other Classes, below). Class 376, however, takes such patents if some reactor structure is claimed or if the resulting product is either claimed or disclosed as being radioactive.
SEE OR SEARCH THIS CLASS, SUBCLASS:
100+, for patents to processes or devices that utilize a gaseous or light element fuel material, the particles of which are electrically charged or excited to the point where they become highly ionized and the forces of repulsion of like nuclei is overcome, or substantially so, wherein it is the intent of the patent that this be the result of such ionization, to the end that nuclear fusion of such like nuclei is obtained or sought to be obtained.
156+, for patents to processes or apparatus including a step or means for (a) converting the nucleus of a substance other than the reactor fuel to a nucleus of another substance, (b) treating or irradiating of material, or (c) making a material radioactive, all within such reactor, including for such purposes as the production of nuclear fuel or experimentation, study or research, etc.
156+, patents to all devices, structures, and processes for irradiating a nucleus with its antinucleus (e.g., protonantproton) so as to produce annihilation radiation, i.e., induced matter-antimatter reaction.
190+, for patents to processes or apparatus including a step or means for converting the nucleus of a substance or for making a substance radioactive by bombardment with accelerated particles from a source other than a nuclear reactor. See subclasses.
317+, for patents directed to combination of a process or apparatus under the class definition with a step or means, e.g., (a) of cooling or heat exchange even though the purpose is to generate steam for extraneous uses, or (b) with a step or means for carrying out of a chemical reaction, etc.
347, for patents to processes or apparatus including an arrangement of steps or means for amplifying neutrons of a subcritical mass to controllable fission reaction levels, i.e., subcritical reactors.
REFERENCES TO OTHER CLASSES
SEE OR SEARCH CLASS
47, Plant Husbandry, appropriate subclasses for processes of subjecting living plant or plant matter to nuclear radiation devices other than within a nuclear reactor. 60, Power Plants,
644.1, for a power plant energized by externally applied heat in which heat directly from radioactive decay or indirectly from a nominally recited nuclear reactor is used.
74, Machine Element or Mechanism, appropriate subclasses for control elements, per se, (including its moving parts) except where (a) the element is structurally associated with the
reactor and some reactor structure is also recited (other than in a mere broad reference to the reactor), or where (b) the control element or portion thereof is defined as being absorbing material or neutron absorbing material - patents to such elements are classified in this class (376).
114, Ships, appropriate subclasses for patents to ship structures utilizing nuclear reactors for power-generating purposes in which no structural elements of the nuclear reactor are claimed.
166, Wells,
247, for well processes involving nuclear energy in general.
204, Chemistry: Electrical and Wave Energy,
157.2+, and 193 for processes and structure for bringing about chemical reactions by subjecting material to nuclear radiation; subclasses 157.15+ for patents to processes utilizing nuclear energy to bring about chemical reactions between either inorganic or organic compounds in order to provide a different compound or product, provided neither reactor structure nor a nuclear reaction is claimed. (See Lines With other Classes, "Reactor structure in combination with any other art device.").
53+, for patents to aircraft using a nuclear reactor as a power-generating source in which no structural elements of the nuclear reactor is claimed.
250, Radiant Energy, 251, for molecular or atomic beam devices for producing and propagating a unidirectional stream of neutral molecules or atoms through a vacuum, usually at thermal velocities; subclasses 253+ for geological signal processing steps or apparatus involving only a nominally recited nuclear reaction; subclasses 324+ for methods and apparatus to irradiate materials by corona radiation; subclasses 390.01+ for neutron responsive means involving no induced nuclear reactions; subclasses 423+ for methods and apparatus to generate ions not involving induced nuclear reactions; subclasses 453.11+ for methods and apparatus including supports for objects to be irradiated with or without an irradiating source; subclasses 458.1+ for methods and apparatus to irradiate luminophors; subclasses 492.1+ for methods and apparatus to irradiate objects or materials generally; subclasses 493.1+ for invisible radiation generation and sources not involving induced nuclear reactions; and subclasses 505.1+ for generic storage devices for radioactive material.
290, Prime-Mover Dynamo Plants, appropriate subclasses for prime-mover plant using nuclear reactor as power-generating
source in which no structural elements of the nuclear reactor is claimed.
322, Electricity: Single Generator Systems, appropriate subclasses for patents to generator systems utilizing nuclear reactors for power source in which no structural element of the nuclear reactor is claimed.
378, X-Ray or Gamma Ray Systems or Devices, appropriate subclasses, particularly
120, for gamma ray sources.
424, Drug, Bio-Affecting and Body Treating Compositions, particularly
1.11+, for radionuclide containing subject matter, for: compositions (A) for preventing, alleviating, treating, or curing abnormal and pathological conditions of the living body, for maintaining, increasing, decreasing, limiting, or destroying a physiologic body function, for diagnosing a physiological condition or state by an in vivo test, for controlling or protecting an environment or living body by attracting, disabling, inhibiting, killing, modifying, repelling, or retarding an animal or micro-organism, (B) for deodorizing, protecting, adorning, or grooming a body, (C) for fermentates and extracts for use in A or B and not elsewhere provided for, and (D) for such compositions defined in terms of specific structure; methods of making the above compositions; methods of using the class defined compositions for purposes in A and B; and methods of using compounds, per se, for purposes in A and B.
426, Food or Edible Material: Processes, Compositions, and Products,
240, for process of subjecting food to nuclear radiation devices other than within a nuclear reactor.
522, Synthetic Resins or Natural Rubbers, for a process of utilizing nuclear energy to bring about chemical reactions that treat or prepare a synthetic resin or rubber, provided neither nuclear reactor structure nor a nuclear reaction is claimed.
600, Surgery, 1+, for treatment of the body with radioactive substances.
976, Nuclear Technology, for an alternative search, based on a modification of the European Patent Office Classification.
GLOSSARY:
Certain terms employed in this class have been assigned definitions tailored to meet the needs of this class and therefore may be more or less restricted or even altogether
different from those in common usage. These terms are listed below and are flagged with an asterisk where they occur in the subclass definition that follow. The meaning to be given to the various "art" terms appearing in this class, but which have not been included in the Glossary below, is the same as that generally accepted or is in common usage.
ABSORBING MATERIAL
See Neutron Absorbing Material.
ACTIVE VOLUME
See Reactor Core.
AMPLIFICATION, NEUTRON
See Subcritical Reactor.
BLANKET MATERIAL A layer of fertile material placed external to core of the fission reactor. See Fertile Material.
BREEDER MATERIAL
See (a) Blanket Material and (b) Fertile Material.
BURNABLE POISON
A substance with high neutron capture cross section which has a capture reaction product of low capture cross section and which is purposely put in a fission reactor to influence the long term reactivity variations.
BY-PRODUCT MATERIALS
Are nuclear reaction products (except special nuclear fuel material (see Nuclear Fuel) including gases yielded in or made radioactive by exposure to the radiation incident to the process of producing or utilizing special nuclear fuel in the nuclear reaction.
COMPONENT, REACTOR
For the purpose of this class, relates to any of the functional segments or parts comprising, when properly associated together, a nuclear reactor, e.g., fuel, moderator, coolant (fluid or solid), control rod, reflector, shield, etc.
CONFINEMENT PLASMA
For the purpose of this class, is either the containment or restraint force or the means (structure) for producing such force placed upon the charged particles or plasma, e.g., by electric or magnetic fields, so as to restrict said particles
or plasma within a given volume. CONTROL ELEMENT
For the purpose of this class, is rods, tubes, plates, etc., of a reactivity affecting material used to hold a fission reactor at a given power level or to vary the rate of reaction. Control elements can be given three names corresponding to three different functions, namely: (a) power control, regulating or fine control (affecting only a small change in reactivity); (b) safety or scram (capable or reducing the reactivity below critical and used general when some emergency condition exists, such as power level to high); and (c) shim (affecting a relatively large change in reactivity of a reactor, i.e., it is used for coarse control or reactivity).
CONTROL ROD
See Control Element.
CONVERSION
For the purpose of this class, is the process of artificially bringing about a change or transformation in the nucleus of an atom. Nuclear conversion is generally caused by subjecting a material to particle bombardment, usually by neutron irradiation as happens in a fission reactor. See also Transmutation.
COOLANT
A fluid (liquid, gaseous, or particulate) whose function is to absorb heat from the reactor core and to deliver this absorbed heat to a heat exchanger or other utilization means exterior to the reactor core.
CORE, REACTOR
See Reactor Core.
CRITICAL
For the purpose of this class, is the term used to describe the condition in which a chain reaction is being maintained at a constant level, i.e., it is just self-sustaining. In order for this state to exist a sufficient quantity of fissile material (critical mass) must be assembled in the proper shape and concentration. FAST NEUTRONS
See Thermal Neutrons.
FAST (FISSION) REACTOR
A nuclear reactor in which most of the fissions are caused by
neutrons moving with substantially the high speeds they possess at the time of their birth in fission. Such reactors contain little or no moderator.
FERTILE MATERIAL
An element (isotope) capable of being readily transformed or converted into a fissionable substance by capture of a neutron, examples include, U[supscrpt]238[end supscrpt] and Th[supscrpt]232[end supscrpt].
FISSILE MATERIAL
See Fissionable Material.
FISSION
The splitting of a heavy nucleus into two (or, very rarely, more) fragments (fission products) of more or less equal mass accompanied by the emission of neutrons and the release of energy. It can be spontaneous or it can be caused by the impact or a neutron, a fast charged particle or a photon. See Fissionable Material. Cf. Spallation.
FISSIONABLE MATERIAL Any element or isotope the nucleus of which can be caused by nuclear bombardment to undergo nuclear fission and to produce a fission chain reaction U[supscrpt]233[end supscrpt], U[supscrpt]235[end supscrpt], and Pu[supscrpt]239[end supscrpt], are examples. Unless a patent refers to a distinction, "fissionable" and "fissile" are considered synonymous for the purpose of this class.
FLUIDIZED BED (FISSION) REACTOR
A reactor in which the fuel in the form of particles is maintained in a fluidized state by a fluid medium. (The fuel and the fluid are general moving in opposite directions). See subclass 355. (Includes also support of fuel in pellet form in a liquid bath by an upwardly flowing liquid).
FUEL, FUEL ELEMENT, or FUEL COMPONENT
See Nuclear Fuel.
FULLY IONIZED
For the purpose of this class, is state in which atoms are entirely stripped of their orbital electrons for atoms of low mass number, this occurs at kinetic temperatures in the region of 1 Kev or more. In other words, matter is in a state of complete ionization; it consists of a gas composed of positively charged nuclei and an equivalent number of negative electrons with no neutral particles. See also Plasma.
FUSION
For the purpose of this class, is a nuclear reaction in which light nuclei combine to form a nucleus of a heavier mass number. See also Thermonuclear Fusion Reaction.
HOMOGENEOUS FUEL
See Homogeneous Fission Reactor. HOMOGENEOUS (FISSION) REACTOR
A reactor in which the fuel and moderator are intimately mixed or dispersed (e.g., the fuel may be a uranium salt dissolved in heavy water) as a solution or slurry.
INDUCED NUCLEAR REACTION
See section I, (1) Note.
INTERMEDIATE NEUTRONS
See Thermal Neutrons.
IONIZED
See (a) Fully Ionized and (b) Plasma.
MAGNETIC MIRRORS
See Mirror Field.
MIRROR FIELD
For confinement of plasma, a system has been devised whereby a longitudinal magnetic field is applied to the plasma, but instead of being uniform, the field strength is increased at spaced points. The region of enhanced magnetic field is referred to as a mirror field or magnetic mirror. Substantially all of the charged particles moving from the region of lower to that of the higher field strength, will be reflected back into the former region. This field thus acts as a sort of potential well which inhibits escape of many of the charged particles (and consequent loss of energy). MODERATOR
For the purpose of this class, is a substance used within a fission reactor core in special relationship with the fuel to reduce the energy, and hence speed, of fast neutrons (so far as possible) emanating from the fuel by means of collisions without capturing them. Graphite and heavy water are examples.
MODERATED NEUTRONS
See Thermal Neutrons.
NEUTRON ABSORBING MATERIAL
As it relates to nuclear reactors, a substance that poses a high neutron absorption ability.
NEUTRON APLIFICATION
See Subcritical Reactor.
NUCLEAR FUEL
(a) Light elements such as hydrogen, deuterium tritium, lithium, boron beryllium, etc., which are capable of fusing or combining to form a nucleus of higher mass number, (b) fissionable fissile, or special nuclear material such as U[supscrpt]233[end supscrpt], U[supscrpt]235[end supscrpt], or uranium enriched with either of these Pu[supscrpt]239[end supscrpt], etc., capable of sustaining a chain reaction.
NUCLEAR REACTION For the purpose of this class, a change in the composition or physical characteristics of an atomic nucleus produced (a) directly or indirectly, by its irradiation or bombardment by high energy alpha particles, protons, deuterons, slow or fast neutrons or high energy radiations (gamma rays) or (b) by fusing or combining nuclei of low atomic number to produce a nucleus of higher mass number. See also class definition, section I, and (1) Note.
NUCLEAR REACTOR
For the purpose of this class, a structure inside which an induced nuclear reaction is confined, manipulated, or controlled. A nuclear fission reactor is a structure in which a fission chain reaction is a fissionable material can be maintained and controlled. Besides the fuel, it generally contains control apparatus, moderator, coolant, etc., and is often surrounded by a biological shield. A nuclear fusion reactor is a structure in which a fusion reaction in a nuclear fuel capable of fusing is controlled or manipulated. Although it is implied that the rate of such reactions increases as the relative velocities of such particles at the time of collision, nothing is implied about the means by which such precollision velocities are attained. The same reaction may and usually does produce one or more other particles such as neutrons or protons, in accordance with well-known reactions.
PINCH EFFECT
The self-constriction that occurs in a plasma as a result of the passage of a unindirectional current, which current produces an azimuthal self-magnetic field that tends to constrict (or pinch) the plasma; or the equivalent effect which is produced when a plasma is contained between parallel
circuits carrying current in the same direction attracting each other.
PLASMA
For the purpose of this class is a very hot, at least partially, ionized gaseous system consisting of equivalent (substantially so) numbers of positive ions and electrons, irrespective of whether neutral particles are present or not. It is nearly neutral electrically and highly conducting. See also Fully Ionized and subclasses 100+.
REACTION BY-PRODUCTS
See By-Product Materials.
REACTIVITY
A measure of the amount of the possible departure of a reactor from the critical condition where the reaction is just self- supporting. At any steady state of operation the reactivity is zero. Addition of positive reactivity causes divergence; addition of negative reactivity causes the reaction to die down. REACTIVITY AFFECTING MATERIAL
As it relates to fission nuclear reactors, this is a material which affects the criticality of the reactor and can be (a) a neutron absorbing material (which for the purpose of this class is a material which can absorb neutrons without reproducing them, e.g., boron, or a fertile material such a uranium (U[supscrpt]238[end supscrpt] or thorium) thus providing a decrease in reactivity, (b) a fissionable material such as U[supscrpt]235[end supscrpt], Pu[supscrpt]239[end supscrpt], U[supscrpt]233[end supscrpt] (thus providing an increase in reactivity), and (c) a reflector (moderator) material such as graphite or water (thus providing an increase in reactivity).
REACTOR CORE (FISSION REACTOR)
The central or heart of a nuclear reactor containing as its main constituent the nuclear fuel (e.g., enriched uranium, Pu[supscrpt]239[end supscrpt], etc.), and the moderator, if any. Also known as the active volume of the reactor.
REACTOR GEOMETRY (FISSION REACTOR)
See subclasses 347+.
REFLECTOR
A volume of material placed around the active volume (core) or other neutron yielding source serving to scatter back into the active volume some of the neutrons which would otherwise be lost to the chain reaction thus permitting a reduction in
the critical size of the active volume.
SAFETY ELEMENT or ROD
See Control Element.
SCRAM ROD See Control Element.
SHIELD
For the purpose of this class, generally a mass or armor of concrete, lead or other heavy material or other neutron absorbing material erected around a reactor or other radioactive source to shield operating staff by absorbing and reducing dangerous radiations (especially neutrons and gamma rays) to permissible levels. See also Neutron Absorbing Material.
SHIM
See Control Element.
SLURRY
See Homogeneous Reactor.
SPALLATION
A nuclear reaction induced by high energy bombardment and involving the ejection of two or more small particles or fragments leaving only one large residual nucleus.
SPECIAL NUCLEAR MATERIAL
See Nuclear Fuel (b).
SPLITTING See Fission.
STRIPPED of ORBITAL ELECTRONS
See Fully Ionized.
SUBATOMIC PARTICLES
All particles of less than atomic mass, i.e., the elementary particles (proton, neutron, electron, positron, neutrino, meson, etc.) as well as the alpha particles and deutrons, the charge and mass of which indicates them to be composite particles.
SUBCRITICAL (FISSION) REACTOR
For the purpose of this class, is a reactor which has (a) an
active volume (core) containing less than the necessary amount of fissionable material (fuel) to become critical, and (b) an auxiliary neutron source combined therewith in such a way as to trigger fissioning with the active volume and with proper amplification of neutrons whereby a steady state chain reaction results, i.e., it becomes critical.
TARGET
The substance which is subjected bombardment by particles of photons of high energy in order to produce nuclear reactions therein.
THERMAL NEUTRONS
As the energy of any substance has a temperature factor, that of the prevailing temperature is termed thermal energy, and when neutrons reach equilibrium with the moderator they are called thermal neutrons. Their most probable energy is about 0.025 ev; or the speed of a gas molecule at room temperature. It is this type of neutron that can best enter the nucleus of a fissionable atom and remain there long enough to excite the atom to the breaking point, attaining fission. Two other categories of neutrons are intermediate and fast. Fast neutrons are those resulting from fission that have lost relatively little of their energy by collision, etc.; having energies exceeding 0.1 Mev. Intermediate neutrons have energies lying between thermal and fast neutrons. THERMONUCLEAR FUEL
See Nuclear Fuel.
THERMONUCLEAR (FUSION) REACTORS
Apparatus in which fusion reactions occur primarily as the result of random collisions within the apparatus between gas particles having a Maxwellian distribution of velocities about some average temperature. It is implied that such reactions are not the result of accelerating one particle into another. While it is also implied that a high average gas temperature is sought for to attain a high thermonuclear reaction rate, nothing is implied as to the attainment of any minimum temperature.
TRANSMUTATION
The bombardment of a nucleus by particle or photon so as to bring about a change in the nucleus resulting in a different isotope of the original nucleus or resulting in different element(s).