Abstract: A spent nuclear fuel is reprocessed by dissolving a spent nuclear fuel in an aqueous nitric acid solution and separating and recovering nuclides contained in the resulting fuel solution by solvent extraction. A spent nuclear fuel reprocessing method includes: an electrolytic valence adjustment step in which nuclides contained in the fuel solution is electrolytically reduced without removing fission products or minor actinides until valence of plutonium is at a level at which solvent extraction efficiency is low by using the valence of plutonium contained in the fuel solution as a parameter; and a nuclide separation step in which, by using an extraction solvent which extracts uranium contained in the fuel solution, uranium is distributed from the fuel solution subjected to the electrolytic valence adjustment step to the extraction solvent.

Abstract: In one embodiment, a semiconductor device includes a well region of a second conductivity type, a control electrode, a first main electrode and a second main electrode. The well region has a source region and a drain region of a first conductivity type selectively formed in a surface of the well region. The control electrode is configured to control a current path between the source region connected to the first main electrode and the drain region connected to the second main electrode. With respect to a reference defined as a position of the well region at an identical depth to a portion of the source region or the drain region with maximum curvature, a peak of impurity concentration distribution of the second conductivity type is in a range of 0.15 micrometers on a side of the surface of the well region and on a side opposite to the surface.

Abstract: According to one embodiment, a process for producing rare metals includes the steps of: electrolyzing an electrolytic solution to extract a Re oxide at a cathode; recovering the Re oxide, and electrolyzing the Re oxide in a molten salt electrolyte to extract metallic Re; recovering a Nd containing residue solution; treating the Nd containing residue solution to produce Nd oxide; electrolyzing the Nd oxide in a molten salt electrolyte to extract metallic Nd; recovering a Dy containing residue solution; treating the Dy containing residue solution to produce Dy oxide; and electrolyzing the Dy oxide in a molten salt electrolyte to extract metallic Dy.

Abstract: In one embodiment, a semiconductor device includes a well region of a second conductivity type, a control electrode, a first main electrode and a second main electrode. The well region has a source region and a drain region of a first conductivity type selectively formed in a surface of the well region. The control electrode is configured to control a current path between the source region connected to the first main electrode and the drain region connected to the second main electrode. With respect to a reference defined as a position of the well region at an identical depth to a portion of the source region or the drain region with maximum curvature, a peak of impurity concentration distribution of the second conductivity type is in a range of 0.15 micrometers on a side of the surface of the well region and on a side opposite to the surface.

Abstract: According to one embodiment, a process for producing rare metals includes the steps of: electrolyzing an electrolytic solution to extract a Re oxide at a cathode; recovering the Re oxide, and electrolyzing the Re oxide in a molten salt electrolyte to extract metallic Re; recovering a Nd containing residue solution; treating the Nd containing residue solution to produce Nd oxide; electrolyzing the Nd oxide in a molten salt electrolyte to extract metallic Nd; recovering a Dy containing residue solution; treating the Dy containing residue solution to produce Dy oxide; and electrolyzing the Dy oxide in a molten salt electrolyte to extract metallic Dy.

Abstract: A spent nuclear fuel is reprocessed by dissolving a spent nuclear fuel in an aqueous nitric acid solution and separating and recovering nuclides contained in the resulting fuel solution by solvent extraction. A spent nuclear fuel reprocessing method includes: an electrolytic valence adjustment step in which nuclides contained in the fuel solution is electrolytically reduced without removing fission products or minor actinides until valence of plutonium is at a level at which solvent extraction efficiency is low by using the valence of plutonium contained in the fuel solution as a parameter; and a nuclide separation step in which, by using an extraction solvent which extracts uranium contained in the fuel solution, uranium is distributed from the fuel solution subjected to the electrolytic valence adjustment step to the extraction solvent.

Abstract: A spent fuel reprocessing method has a dissolution step of dissolving the spent fuel in nitric acid solution, an electrolysis/valence adjustment step of reducing Pu to trivalent, maintaining the pentavalent of Np, a uranium extraction step of collecting UO2 by bringing the fuel into contact with organic solvent and extracting hexavalent U by means of an extraction agent, an oxalic acid precipitation step of causing MA and the fissure products remaining in the nitric acid solution to precipitate together as oxalic acid precipitate, a chlorination step of converting the oxalic acid precipitate into chlorides by adding hydrochloric acid to the oxalic acid precipitate, a dehydration step of synthetically producing anhydrous chlorides by dehydrating the chlorides in a flow of Ar gas, and a molten salt electrolysis step of dissolving the anhydrous chlorides into molten salt and collecting U, Pu and MA at the cathode by electrolysis.

Abstract: An anomaly diagnosis system for a nuclear reactor, comprising ultrasonic wave reflecting members and an ultrasonic wave emitter-receiver. The ultrasonic wave reflecting members are provided respectively on the fuel assemblies, and include a shape memory alloy which permits changing the shape thereof. The ultrasonic wave emitter-receiver is located exterior of the reactor vessel, and includes means for providing an anomaly detection signal to the plant protection system when the ultrasonic wave reflected by any one of the ultrasonic wave reflecting members is not received by the ultrasonic wave emitter-receiver.

Abstract: An anomaly diagnosis system for a nuclear reactor core comprises an anomaly detecting unit incorporated into a fuel assembly of the nuclear reactor core, and a transmitter-receiver provided outside the reactor vessel, which transmits a signal by wireless to the anomaly detecting unit and receives an echo signal generated by the anomaly detecting unit by wireless. When the anomaly detecting unit detects an anomaly in the nuclear reactor core, such as an anomalous temperature rise in the fuel assembly, the mode of the echo signal deviates from a reference signal mode, and then the transmitter-receiver detects the deviation of the mode of the echo signal from the reference signal mode and gives an anomaly detection signal to a plant protection system, and thereby the nuclear reactor can be shut down without delay.