Abstract: According to the present invention there is provided a container for the storage and transport of nuclear fuel elements comprising a plurality of elongate compartments for receiving the nuclear fuel elements, the compartments being defined by a first set of plates intersecting with a second set of plates, the first set of plates extending perpendicularly with respect to the second set of plates to define compartments having a rectangular cross section, wherein the plates include an interlocking joint, the interlocking joint comprising at least one projection provided on one plate and a recess formed in the other plate, and wherein a retaining portion is provided in the recess for engagement by the projection so as to interlock the plates.

Abstract: The installation is designed for loading a nuclear fuel assembly that comprises a skeleton structure defining parallel locations for receiving fuel rods distributed in sheets. The installation comprises a horizontal bench (22) for receiving a skeleton structure, a magazine (16) for receiving rods for loading in a disposition that corresponds to that of the rods in the assembly, and a pulling bench (26) having a block of pulling or pushing elements enabling a plurality of rods to be slid simultaneously from the magazine into the skeleton structure. The bench makes it possible for a set of clamps from a plurality of sets each corresponding to a particular type of assembly to be fixed removably thereto by quick coupling and uncoupling means closed by actuators. The pulling bench (26) receives one out of a plurality of pulling element selector blocks, each block having a disposition of active pulling elements corresponding to a particular distribution of rods.

Abstract: A process and apparatus for producing the 18F isotope from water enriched with the 18O isotope using high energy protons from a cyclotron. The apparatus has a cyclotron target cavity that is connected to a fluid loop that contains a water reservoir, pump, and pressure regulator. Water is continuously recirculated through the target cavity to increase reliability. After irradiation long enough to produce a desired amount of 18F, water in the target loop is diverted through an 18F extraction device before being returned to the target loop. The returning water may also be purified and additional water added to the target loop as needed to permit continuous irradiation and production of 18F.

Abstract: The neutron monitoring system measures neutrons by counting both the negative pulse signals and the positive noise pulse signals output from a neutron detector 1, and subtracts the positive pulse count from the negative pulse count per unit time, thereby measuring the neutrons.

Abstract: A method for inspecting an irradiated fuel element in a nuclear power plant includes the step of measuring, with a measuring device, a spacer of a fuel element for providing measurements of the spacer. The measuring device also measures a calibration rod for providing measurements of the calibration rod, the calibration rod having known dimensions. The measurements of the spacer are calibrated by using the measurements of the calibration rod. It is possible thereby to measure at least the maximum width of the spacer with a measuring error of less than 20 &mgr;m. A device for inspecting an irradiated fuel element in a nuclear power plant is also provided.

Abstract: Water rod segments are provided in a nuclear fuel bundle and releasably connected one to the other at joints within openings through the spacers. A lowermost water rod segment passes through a number of the spacers, with water rods segments above the lowermost segment being screwthreaded one to the other forming joints therebetween within the spacer openings. Capture flanges are provided immediately above and below the spacers on each of the segments such that the spacer is captured between adjoining segments. Interior passages through the segments communicate water along the water rod to an upper region of the fuel bundle. Swirler vanes are disposed about the water rod segments and terminal ends of the swirler vanes may form the capture flanges, retaining the spacer between adjacent segments.

Abstract: A supercritical pressure water cooled reactor comprising: a reactor vessel including: a shell part for containing sub-critical pressure coolant, and an end part for containing supercritical-pressure coolant which is separated from the sub-critical pressure coolant in the reactor vessel. A core-support plate with through-holes, the core-support plate disposed-in and fixed to the reactor vessel so that the core-support plate divides space inside the reactor vessel into a supercritical-pressure portion and a sub-critical pressure portion. Fuel tubes with both open ends fixed to the through-holes, the open ends being communicated to the supercritical-pressure portion, outside of the fuel tubes being disposed in the sub-critical pressure portion; and nuclear fuel assemblies disposed in the fuel tubes.

Abstract: The neutron monitoring system measures neutrons by counting both the negative pulse signals and the positive noise pulse signals output from a neutron detector 1, and subtracts the positive pulse count from the negative pulse count per unit time, thereby measuring the neutrons.

Abstract: There are provided a light water reactor core which has the same levels in cost efficiency and degree of safety as those of an existing BWR under operation now, that is, which is oriented to plutonium multi-recycle having a breeding ratio near 1.0 or slightly larger and having a negative void coefficient with minimizing modification of the reactor core structure of the existing BWR under operation now, and to fuel assemblies used for the boiling water reactor. The light water reactor core having an effective water-to-fuel volume ratio of 0.1 to 0.

Abstract: A storage/transport container for radioactive material has a metallic outer shell, a metallic inner shell concentrically received in the outer cell and defining therewith an annular space, and an annular and continuous heat-conductive meander strip in the space. The strip is formed unitarily with a plurality of angularly spaced inner segments engaging the inner shell, respective angularly spaced outer segments engaging the outer shell, and respective generally radially extending webs extending between the inner and outer segments.

Abstract: The exit thermocouples of a pressurized water reactor (PWR) are calibrated by recording the thermocouple temperature measurements periodically during power ascension of the reactor together with a predicted power at the corresponding locations at the same time determined by a three-dimensional analytical nodal model of the core at the same core average power. The temperature measurements are converted to local core power values which are then divided into the corresponding predicted powers for the corresponding locations to arrive at mixing factors which are fitted to a selected function of core power. These mixing factors are recorded and subsequently applied to local power values calculated from measured exit thermocouple temperatures to adjust the three-dimensional nodal model power.

Abstract: A remotely installable piping support device includes a pair of mating tapered wedge segments extending from lever arms connected with a spiral wound spring. The spring is machined integrally with the left lever arm and has a projecting center square drive hub with an internal mounting thread. The right lever arm has an internal square drive which mates with the drive hub. A bolt engages the drive hub and secures the lever arms together. The spring preload on the wedge acting across the shallow angled wedge surfaces maintains rigid contact between jet pump components and takes up the clearance from wear during operation.

Abstract: A nuclear reactor instrumentation system including a plurality of incore nuclear instrumentation assemblies arranged in a gap between a number of fuel assemblies charged in a reactor core. The incore nuclear instrumentation assemblies each include a fixed type neutron detector having a plurality of fixed type neutron detectors dispersively arranged in a core axial direction and a fixed type gamma thermometer assembly having a plurality of fixed type gamma ray heat detectors arranged at least in a same core axial direction as the fixed type neutron detectors. A power range detector signal processing device operatively connected to the fixed type neutron detector assemblies through signal cables. A gamma thermometer signal processing device is operatively connected to the fixed type gamma thermometer assembly of the incore nuclear instrumentation assembly through a signal cable.

Abstract: A flexible penetration attachment for BWR wet-well strainers is provided that causes a suction pipe to communicate with liquid in the wet-well through an aperture in a wet-well wall. The penetration includes a boot for defining an outer circumference of the aperture. A suction pipe having an outer surface extends through the aperture such that an annular space is defined between the aperture outer circumference and the suction pipe outer surface. A resilient seal having a generally U-shaped cross section with first and second ends is placed within the annular space. The first end is fixedly secured to the outer surface of the suction pipe and the second end is fixedly secured to the aperture outer circumference such that the suction pipe may move in response to a force applied to the suction pipe.

Abstract: Detonator apparatus, such as a blasting machine detonator, is provided with a miniature transformer having multi-turn primary and secondary coils. The transformer feeds a bridge wire detonator element, and has sufficient impedance to permit impedance matching with a carrier that may be as long as 7500 m. The impedance of the detonator is such that the detonator resists firing when subject to stray currents or commonly present power or communications signals. A blasting machine is provided that is specifically designed to provide a signal having a frequency in the range in which the detonator is sensitive. The blasting machine relies upon semi-conductor switching and timing circuits to control the discharge from a pair of capacitors, rather than upon an output transformer.

Abstract: A non-steady state computer model of water in a Boiling Water Reactor (BWR) primary water flow circuit is used to represent the water chemistry and noble metal loading during, for example, an in situ noble metal application process. The modeling software is provided on a laptop or portable computer for real-time use in the field at different reactor sites. After inputting data representing the initial state of reactor water chemistry and operating conditions of the reactor, the model determines the water chemistry, pH, conductivity and noble metal loading throughout the BWR primary water flow circuit, including selected sample locations, as a function of time. Results are used to determine whether technical specifications on conductivity or other chemistry-related parameters will be exceeded during the noble metal application process. Values of rate constants used for modeling noble metal reactions may be changed on site at the reactor during the application process.

Abstract: A boiling water reactor having a reactor pressure vessel with two recirculation loops hydraulically connected thereto is decontaminated by installing plugs in the outlets of jet pump ram's head manifolds located within the reactor pressure vessel to isolate the recirculation loops from the reactor pressure vessel. A monitoring gas is bubbled into some of the ram's head manifolds through the plugs to monitor the process pressure within the manifolds and riser pipes connected with the manifolds. The level of the decontamination solution in the riser pipes can be determined by determining the differential pressure due to the vertical height of the decontamination solution in the loops.

Abstract: A CRUD collection system for removing deposits from a nuclear reactor fuel rod submerged in pool water. The system includes a sealable collection head for containing a portion of the fuel rod. The collection head includes at least one seal positioned to receive the fuel rod. Also provided is a liquid inlet communicating with an interior portion of the collection head, the inlet is configured to inject a liquid into the interior to displace the pool water therefrom. At least one blade is provided that is positionable in scraping engagement with the fuel rod. Also included is a liquid outlet for eliminating a CRUD sample and the liquid to a filter.

Abstract: A method is provided for the quantitative determination of fissile material content in small size particles present in samples. The samples are sandwiched in organic sheets and then submitted to a defined thermal neutron fluence whereupon fission products of the fissile material in the sample create in the sheets fission tracks which are rendered visible by etching the sheets. Then the size of selected particles having created such tracks is. determined by means of a microscope and thereafter these visible tracks of the selected particles are compared to pre-established standard tracks obtained by the same process from particles of different stepped known size and enrichment ratio.

Abstract: A core spray sparger T-box attachment assembly for a nuclear reactor pressure vessel includes a downcomer pipe coupling and a sparger T-box clamp. The downcomer pipe coupling includes a cylindrical outer housing, a center portion, and a plurality of vanes extending the outer housing to the center portion. The outer housing is coupled to a downcomer pipe and includes an extending flange. A draw bolt threadedly engages an axial bore in the center portion, and connects the downcomer pipe coupling to the sparger T-box clamp. The sparger T-box clamp includes an anchor having a draw bolt opening, and a plurality of legs extending from a face of the anchor. Clamp blocks are connected to the anchor. Stop bolts extend through stop bolt openings in the clamp blocks. Clamping elements are connected to the clamp blocks by clamp bolts. A seal plate having a draw bolt opening is coupled to the anchor with a plurality of adjusting screws.