Abstract: This invention relates to an analytical method and a relevant equipment for particulate substances in a sample with the detection of acoustic waves generated in the sample with the irradiation of onto the sample. In this invention, the light power density of the irradiating light onto the sample is set high enough above the breakdown threshold of the particulate substances in the sample, and low enough below the breakdown threshold of the media, and the particulate substances in the sample are counted by detecting the acoustic waves generated by the breakdown of the particulate substances. The particulate substances are also analyzed for their components on the basis of the light signal (emission spectrum) which is detected with a dispersed spectrum from the light which is generated by the breakdown of the particulate substances.

Abstract: The power density of a pulsed laser beam for irradiating a sample is adjusted to break down the sample into the form of a plasma. After the momentary breakdown of the sample into the form of a plasma, ions are generated having a high charge. Then, after a certain time elapses, the ions having a high charge recombine with the electrons in the plasma to provide monovalent or low valent ions. These low valent ions are taken out of the plasma and introduced to a mass spectrometric apparatus.

Abstract: A method of and an apparatus for analyzing a granular material contained in a sample of a medium such as water produced by an ultra-pure water producing apparatus includes the steps of adding energy to granular materials contained in a sample which is mixed with the medium, wherein the energy is set to be lower than the breakdown threshold of the medium and to be higher than the breakdown threshold of the granular materials, detecting ions which are generated with the breakdown of the granular materials by using a pair of positive and negative electrodes; and analyzing characteristics of the granular materials based on the ions.

Abstract: A direct cycle type atomic power plant provided with a means for suppressing transfer of radioactive nitrogen compounds generated by nuclear reaction in the core from the reactor water to steam, where an increase in the dose rate in the main steam system and the turbine system due to carry-over of radioactive nitrogen atom, .sup.16 N, generated in the core can be suppressed, and the radioactivity therein can be reduced.

Abstract: Apparatus for measuring breakdown plasma, comprising an irradiating device for irradiating a sample with a focused light beam and for causing breakdown of a ultrafine particle to be measured in the sample at the focused beam region to change the particle into plasma; a pair of electrodes arranged on opposite sides of the focused region of the beam; and a device for measuring an electrical resistance between the electrodes under a condition where the breakdown plasma is produced between the electrodes and for determining a diameter of the particle according to the measured electrical resistance serves for accurate measurement of the diameter of the ultrafine particle in the sample.

Abstract: Disclosed is a method and apparatus for inhibiting radioactive substances eluting into cooling water of a nuclear plant. The method uses an index consisting of an amount of iron adhered onto the fuel cladding surface, that is calculated from the iron concentration of the cooling water and the operation time. A formation of a layer of the iron oxide on the fuel cladding surface is confirmed based upon the covering ratio of 100%. When the covering ratio is smaller than 100%, the iron concentration in the cooling water is controlled to remain constant at a maximum concentration. The Fe/Ni molar concentration ratio in the cooling water is adjusted to be set from about 2 to 10 after the layer of iron oxide reaches a covering ratio of 100%. .sup.58 Co ion and .sup.60 Co ion concentrations in the cooling water can be decreased without greatly increasing the concentration of precipitating radioactive crud, and the surface dosage in the primary system can be decreased at the time of regular checking.

Abstract: Electric conductivities of an aqueous solution under measurement are measured at two or more different temperatures in a range To to Tn, and a relationship between the electrical conductivity and the temperatures is obtained. A solute substance in the aqueous solution is determined by applying this relationship against a known temperature and electrical conductivity relationship of an individual substance. A concentration of the determined substance is estimated by applying the electrical conductivity at the lowest temperature To to a known relationship between an electrical conductivity and a concentration at the same temperature To with respect to an individual substance.

Abstract: A .gamma. ray emitted from a reference radioactive ray source is radiated from outside to a solid radioactive waste. The radioactive intensity of the .gamma. ray emitted from the solid radioactive waste is measured during the radiation of the .gamma. ray. The radioactive intensity to be measured is discriminated into the first radiation intensity based on the reference radioactive ray source and the second radiation intensity based on the radioactive nuclide of the solid radioactive waste. A radiation absorption coefficient of the solid radioactive waste is determined based on the first radiation intensity. The distribution of radioactivity of the solid radioactive waste is determined based on the radiation absorption coefficient and the second radiation intensity.

Abstract: A method of controlling the output power of a nuclear reactor core in which an output power distribution in the core is controlled with the use of an output power controlling means for controlling control rods, a flow of coolant or a concentration of neutron absorbing substance. Core data is calculated to include an output power distribution and a burn-up degree distribution in a fuel assembly, in accordance with detected data of the controlling means. Fuel rod data, which includes a temperature distribution, a stress distribution, a strain distribution and a concentration of fission products in a fuel rod, is calculated in accordance with the core data. Then, a failure event probability in the fuel rod is calculated in accordance with fuel rod data, the failure event probability being correlated with the history of the fuel rod concerning stress corrosion, strain and fatigue of the fuel rod. The soundness of the fuel rod is determined by comparing the failure event probability with a set value.