Abstract: The present invention relates to an irradiation device for material test using a gamma ray radiated from a spent nuclear fuel assembly and provides the irradiation device for material test using a gamma ray radiated from a spent nuclear fuel assembly wherein an irradiation device for material test to achieve a radiation effect evaluation is manufactured to be movable upward, downward and horizontally in order to study the hardening phenomenon of the frail materials to the radiation among the atomic power facilities using a gamma ray radiated from a spent nuclear fuel assembly, thereby it is possible to adjust a position of the spent nuclear fuel used for material test using a gamma ray radiated from a spent nuclear fuel and a test material, identify a distance between the spent nuclear fuel and the test material easily with a scale and evaluate the radiation effects on the materials used at facilities handling a spent nuclear fuel under the same situation as they are really exposed.

Abstract: A signal processing apparatus includes: a digital processing unit to which a digital input signal is supplied, which performs a digital process on the digital input signal to produce a digital signal, and which produces a control signal designating a specific time period when an amplitude of an analog output signal is to be lowered; a DA-conversion unit which converts the digital signal to produce an analog signal; and a variable gain unit which adjusts an amplitude of the analog signal to produce the analog output signal, and which lowers the amplitude of the analog output signal during the specific time period designated by the control signal.

Abstract: A conduction cooled neutron absorber may include a metal matrix composite that comprises a metal having a thermal neutron cross-section of at least about 50 barns and a metal having a thermal conductivity of at least about 1 W/cm·K. Apparatus for providing a neutron flux having a high fast-to-thermal neutron ratio may include a source of neutrons that produces fast neutrons and thermal neutrons. A neutron absorber positioned adjacent the neutron source absorbs at least some of the thermal neutrons so that a region adjacent the neutron absorber has a fast-to-thermal neutron ratio of at least about 15. A coolant in thermal contact with the neutron absorber removes heat from the neutron absorber.

Abstract: A method of early sensing of water leakage, through chemical concentration monitoring, in a nuclear reactor system using a liquid metal and molten salt, the method including: measuring an electrical conductivity and a mass spectrum of a first channel and a second channel of a heat-related device included in the nuclear reactor system using the liquid metal and the molten salt; calculating a first identification value associated with the water leakage in the heat-related device using the measured electrical conductivity; calculating a second identification value associated with the water leakage in the heat-related device using the measured mass spectrum; and sensing the water leakage by comparing a predetermined reference value and a summed identification value, the summed identification value being the sum of the first identification value and the second identification value.

Abstract: A dynamic port that extends from the bottom wall of an oil reservoir that surrounds the lower guide bearing of a reactor coolant pump and is in fluid communication within an oil level gauge. The dynamic port is rotatable into and out of the oil flow path to adjust the dynamic oil level shown by the oil level gauge when the pump is at operating speed to be substantially equal to the static oil level when the motor is at rest.

Abstract: An alignment system that employs jacking block assemblies and alignment posts around the periphery of the top plate of a nuclear reactor lower internals core shroud to align an upper core plate with the lower internals and the core shroud with the core barrel. The distal ends of the alignment posts are chamfered and are closely received within notches machined in the upper core plate at spaced locations around the outer circumference of the upper core plate. The jacking block assemblies are used to center the core shroud in the core barrel and the alignment posts assure the proper orientation of the upper core plate. The alignment posts may alternately be formed in the upper core plate and the notches may be formed in top plate.

Abstract: The present invention relates generally to an apparatus of assembling a capsule for neutron-irradiation experiments. The capsule may contain test specimens to develop nuclear fuel, and may comprise a capsule main body and protection tube that may be assembled and disassembled using separate joining means. The present invention provides a capsule assembling apparatus that may enable safe and easy assembly/disassembly of the capsule placed at a given depth in a working pool through remote working. The capsule assembling apparatus may comprise a base structure loading the capsule main body, a guiding pipe of a given length extending from the base structure to provide a pathway through which the capsule main body is loaded on the base structure, a damper fixing the capsule main body to the guiding pipe, and a coupler coupling the capsule main body with the protection tube.

Abstract: An instrumented capsule for nuclear fuel irradiation tests in research reactors includes an outer shell; a rod tip assembly assembled to a lower end plate of the shell, thus absorbing impact; fuel rod assemblies supported in the shell by means of support tubes and housing therein, sintered fuel bodies and in-capsule instruments, such as thermocouples and self-powered neutron detectors (SPND); a protective tube connected to the upper end plate and protecting instrument control cables; and a guide pipe connected to the inclined extension part of a junction tree and guiding the instrument control cables to a control unit provided outside the reactor.

Abstract: The present invention provides a remote-controlled in-pile creep test system used in in-pile creep tests for measuring and determining mechanical properties of nuclear materials irradiated in research reactors.

Abstract: A preventive maintenance method and apparatus for a structural member in a reactor pressure vessel according to the present invention reduce a tensile residual stress on a surface of the structural member by impinging a water jet from a nozzle onto a plane surface of a deflector to thereby change direction of flow of the water jet, and impinging the water jet after being deflected onto the surface of the structural member. This method and apparatus are applicable to a narrow space portion, and can improve a residual stress on the surface of the structural member and can also prevent damage such as stress corrosion cracking.

Abstract: A testing device for load-testing of specimens (3) in a nuclear reactor environment is attached to one of the pipes (1) of the reactor for conveying a first medium under pressure and provides a first space (14) in open communication with the pipe (1). In the first space (14) a movable pull rod (15) is arranged, one end of which is attached to one half (16) of a specimen (3) arranged in the space (14). The other end of the pull rod (15) is joined to a tensile force device capable of being influenced by the first medium for achieving a tensile stress in the specimen (3).

Abstract: Low frequency broadband energy is separated from an accelerator structure ndamental radio frequency (rf) energy in the broadband electromagnetic energy within specific frequency bands. The particle beam accelerator electromagnetic arc detection system comprises employing signal lines extended from existing particle beam accelerator diagnostic sensors to electrical filter circuits. Depending on the application requirements, filters are grouped by types such as low-pass, high pass, or bandpass types. The bandpass filters are employed in banks in a preferred embodiment to reject all electrical signals except those within the band of interest. The increase in broadband electromagnetic energy radiated through the accelerator structure as an arc begins to form is readily detectable in the rf spectrum at frequencies below 10 MHz. The electrical signals received by the filters are subsequently passed to detectors which produce a direct current (DC) level proportional to the strength of the signal.

Abstract: A high flux reactor is comprised of a core which is divided into two symetric segments housed in a pressure vessel. The core segments include at least one radial fuel plate. The spacing between the plates functions as a coolant flow channel. The core segments are spaced axially apart such that a coolant mixing plenum is formed between them. A channel is provided such that a portion of the coolant bypasses the first core section and goes directly into the mixing plenum. The outlet coolant from the first core segment is mixed with the bypass coolant resulting in a lower inlet temperature to the lower core segment.

Abstract: An irradiator which can be incorporated within a packing house and a method of irradiating food in the packing house are disclosed. Food products are placed on spaced baskets and conveyed into an enclosure, through a irradiation chamber, and then outwardly from the enclosure. The food products are conveyed through tortuously arranged ductwork which serves to absorb radiation streaming upwardly. The radiation source is maintained underwater both during operation and shutdown, and no lifting of the radiation source is thus required. A portion of the conveyor is positioned within one or more casings and can be withdrawn, if necessary, to facilitate maintenance and repair.

Abstract: A rotating, radiation shielded crane system for use in a high radiation test cell, comprises a radiation shielding wall, a cylindrical ceiling made of radiation shielding material and a rotatable crane disposed above the ceiling. The ceiling rests on an annular ledge intergrally attached to the inner surface of the shielding wall. Removable plugs in the ceiling provide access for the crane from the top of the ceiling into the test cell. A seal is provided at the interface between the inner surface of the shielding wall and the ceiling.

Abstract: An apparatus for examining a circumferential surface of each of a plurality of tubular members disposed in axially parallel relationship with each other has a rail adapted to extend between adjacent tubular members; a truck movable on and along the rail, a support frame having mounts at each end tiltably mounting the support frame on the truck for tilting around an axis extending along the rail, and a tilting mechanism connected to the support frame for tilting the support frame. A semi-circular shaped beam is mounted on the support frame for rotation around an axis through the center of the circle on which the semi-circular shaped beam lies and open laterally of the rail, and a sensing element is disposed at a predetermined position on the semi-circular shaped beam.

Abstract: An ultrasonic beam is sent into liquid metal from a transmitting point (3) outside the enclosure (1) containing the liquid metal, the beam is detected outside the enclosure (1) after it has passed through the liquid metal, the amplitude of the ultrasonic waves detected is compared with the amplitude of the transmitted ultrasonic waves and the attenuation of the ultrasounds produced by the passage through the liquid metal which may contain gas bubbles (2) is determined. The device comprises a wave guide (4) metallurgically connected to the enclosure (1). A processing unit (10) connected to the ultrasonic transducers (3, 6) measures the attenuation.

Abstract: A tumorous patient is injected with a compound including an element that accumulates in tumors and that has an isotope which emits an alpha particle in a neutron capture reaction. The patient is positioned in front of a radiation beam that has been filtered to remove most neutrons having energies above 30 KeV and most thermal neutrons, leaving predominantly epithermal neutrons which are moderated to a thermal level by outer layers of tissue and are captured by the incorporated isotope.A radiation beam having neutrons with a wide distribution of energies is filtered with aluminum, sulfur and argon filters, whose cross sections complement each other in providing a beam with energies predominantly in the epithermal range. The filter mass attenuates the gamma radiation. Beams with lower ratios of undesirable gamma radiation to epithermal beam intensity can be attained with filter combinations which include liquid argon. A poor geometry filter of bismuth or lead can also improve the gamma to neutron ratio.

Abstract: A method of and apparatus for heating test specimens to desired elevated temperatures for irradiation by a high energy neutron source. A furnace assembly is provided for heating two separate groups of specimens to substantially different, elevated, isothermal temperatures in a high vacuum environment while positioning the two specimen groups symmetrically at equivalent neutron irradiating positions.

Abstract: An apparatus for irradiating a continuously flowing stream of fluid is diosed. The apparatus consists of a housing having a spherical cavity and a spherical moderator containing a radiation source positioned within the spherical cavity. The spherical moderator is of lesser diameter than the spherical cavity so as to define a spherical annular volume around the moderator. The housing includes fluid intake and output conduits which open onto the spherical cavity at diametrically opposite positions. Fluid flows through the cavity around the spherical moderator and is uniformly irradiated due to the 4.pi. radiation geometry. The irradiation source, for example a .sup.252 CF neutron source, is removable from the spherical moderator through a radial bore which extends outwardly to an opening on the outside of the housing. The radiation source may be routinely removed without interrupting the flow of fluid or breaching the containment of the fluid.