Abstract: A dose distribution-measuring method capable of grasping a three-dimensional form of an object to be measured or evaluating a three-dimensional dose distribution thereof. The method comprises providing a multiple-eye type radiation meter probe in which at least two directional radiation detectors are arranged so as to be spaced from each other and directed toward a point to be measured; and carrying out dose measurement by directing the radiation meter probe toward an object to be measured from different positions to thereby determine a three-dimensional dose distribution of the object to be measured. Each of the radiation detectors has a structure in which a periphery of the radiation detector main body, except for a detection surface thereof, is surrounded by a radiation shield to reduce the effect of radiation from other than the object to be measured and from Compton scattering.

Abstract: A directivity-type radiation detecting apparatus capable of detecting a particular radiation source or a moving situation thereof even in the high radiation atmosphere. A multiplicity of radiation detector probes are dispersedly arranged in different directions on an outer surface of a radiation shield. Alternatively, a multiplicity of penetration holes are dispersedly formed in different directions in a shell-shaped radiation shield and radiation detector probes are respectively disposed in the penetration holes of the radiation shield. The above-described directivity-type radiation detecting apparatus is used to compute and process a position and a direction of each radiation detector probe and a value measured by each radiation detector probe, whereby a position, a distribution situation or a moving situation of a radiation source is detected.

Abstract: A dose distribution measuring method capable of grasping a three-dimensional form of an object to be measured or evaluating a three-dimensional dose distribution thereof. The method comprises providing a multiple-eye type radiation meter probe in which at least two directional radiation detectors are arranged so as to be spaced from each other and directed toward a point to be measured; and carrying out dose measurement by directing the radiation meter probe toward an object to be measured from different positions to thereby determine a three-dimensional dose distribution of the object to be measured. Each of the radiation detectors has a structure in which a periphery of the radiation detector main body, except for a detection surface thereof, is surrounded by a radiation shield to reduce the effect of radiation from other than the object to be measured and from Compton scattering.

Abstract: Herein disclosed is a dual-tube heat pipe type heat exchanger comprising a heat pipe confined with a working fluid for transferring a heat as a latent heat by repeating evaporations and condensations. The heat pipe includes an outer tube which is disposed within a hot fluid such that its axis is generally horizontal. Further included is an inner tube which is inserted in the outer tube and radially offset upward to substantially contact with the top portion of the inner face of the outer tube and to confine a space between the inner circumference of the outer tube and the outer circumference of the inner tube, thus forming the heat pipe.

Abstract: A heat pipe type heat exchanger, such as a steam generator for use in combination with a fast breeder reactor, comprises two double walls consisting of an outer wall and an inner wall and of an outer wall and an inner wall, respectively, and a plurality of double tubes each consisting of an inner tube and an outer tube coaxially receiving the inner tube therethrough. A heating fluid flows through spaces between the outer tubes and the inner walls of the double walls, while a heated fluid flows through the inner tubes. A heat transfer medium is contained in evaporating spaces each defined by the inner surface of the outer tube and the outer surface of the inner tube. The heat transfer medium is evaporated by the heat of the heating fluid, condenses over the surfaces of the inner tubes to transfer heat to the heated fluid flowing through the inner tubes. Each evaporating space is partitioned into many sections by baffle plates to enhance the heat flux in the evaporating space.

Abstract: A double-cylinder selector valve for detecting and locating failed nuclear fuel assemblies including a fixed outer cylinder provided on the circumferential wall surface thereof with a plurality of outer sampling holes arranged in a grid in both the longitudinal and circumferential directions, and a movable inner cylinder disposed rotatably within the fixed outer cylinder and provided on the circumferential wall surface thereof with a plurality of inner sampling holes. Each of coolant sampling pipes extending from the coolant outlets of each of a plurality of nuclear fuel assemblies is connected to one of the outer sampling holes. The inner sampling holes communicate with some of the plurality of outer sampling holes in the fixed outer cylinder at one position of the movable inner cylinder and with others of the outer sampling holes at other positions of the movable inner cylinder.

Abstract: A pressure measuring apparatus using process transmission media and comprising measuring and compensation systems. These systems have the substantially same construction which comprises a pressure receiving portion, a pressure transmitting portion and a pressure detecting portion. The pressure transmitting portion is divided into two sections, each of them contains a liquid NaK and a heat-resisting inert liquid, respectively, as pressure transmission media. A pressure of a fluid to be measured which is introduced into the pressure receiving portion of the measuring system is transmitted through the transmitting portion to the pressure detecting portion where the pressure is detected. A pressure of a gas introduced into the pressure receiving portion of the compensation system is detected in the pressure detecting portion of the compensation system in a same manner. The temperature compensation is conducted by subtracting a detected pressure in the compensation system from that in the measuring system.

Abstract: An apparatus for detection of the level of a liquid metal is disclosed. The apparatus has a liquid level detecting probe provided with an exciting coil wound in a closed bottom non-magnetic sheath over the approximately whole length thereof, a level detecting coil wound in the sheath in an upper part thereof, and a temperature compensating coil wound in the sheath in a lower part thereof; a temperature control for maintaining the coils at a constant temperature; a drive circuit for supplying the exciting coil with an alternating current of a determined frequency and amplitude; and a signal processing circuit for subjecting output voltages induced in the liquid level detecting coil and in the temperature compensating coil to linear detection and then determining the ratio of the thus detected outputs, thereby detecting the level of the liquid metal.