Hitachi, Ltd.

Agency of Industrial Science and Technology

Other

Hitachi Plant Engineering Construction Co., Ltd.

Babcock-hitachi K.k.

Hitachi, Ltd. and Hitachi Plant Engineering and Construction Co., Ltd.

Toshio Sawa

Sankichi Takahashi

Shunsuke Uchida

Makoto Nagase

Katsumi Ohsumi

Yamato Asakura

Seiichi Kikkawa

Kouji Otani

Makoto Kikuchi

Naohito Uetake

Shigeoki Nishimura

Kenkichi Izumi

Masayoshi Kubota

Yoshitaka Nishino

Toyohiko Kaneko

Toshio Ogawa

Takashi Nakao

Nobuo Yoshida

Fumito Nakajima

Shin Tamata

Osamu Kuroda

Michihiko Aizawa

Renzo Takeda

Katsuya Ebara

Koichi Chino

Tsutomu Baba

Masaharu Sakagami

Kenji Yokose

Tsukasa Nishimura

Hisao Itow

Masato Ohura

Ikuo Shimokobe

Toshimi Mukushi

Masayoshi Kondoh

Hidetoshi Karasawa

Tokuji Iijima, Deceased

Sigeoki Nishimura

Shinji Komori

Kosaku Otsubo

Yoshiaki Okazima

Mithumasa Komai

Mitsumasa Komai

An absorption refrigerator is characterized by an absorber which has a tube bank of heat-conductive tubes in the absorber, a vapor flow passage between the tube bank and a side wall of the absorber which is opposite to and separated from the tube bank in a radial direction of the heat-conductive tubes by a distance equal to or larger than a maximum pitch of the heat-conductive tubes, at least a baffle plate disposed in the vapor flow passage, and a gas extraction port disposed outside the tube bank. A further arrangement is characterized by an absorber having a tube bank in the absorber, a vapor flow passage between the tube bank and a side wall of the absorber, and a gas extraction port disposed around a central portion of the tube bank.

Absorption refrigerator

A water quality control method for a nuclear power plant comprising the steps of maintaining the iron concentration in the feed water below 0.05 ppb by increasing iron removing rate at a condensed water purifying loop, shifting the pH of the reactor water below a pH of 6.8 determined at a room temperature by injecting carbon dioxide gas in the primary cooling system and further optionally reducing the dissolved oxygen concentration in the reactor water below 20 ppb by injecting hydrogen gas into the primary cooling system, whereby .sup.60 Co ion concentration in the primary cooling system is maintained low for a long interval.

Water quality control method and device for nuclear power plant, and

An object of the present invention is to provide a method and a nuclear plant capable of preventing deposition and activation of crud to a nuclear fuel rod and decreasing the radioactivity level in reactor water. Metal ions solely having a low deposition rate coefficient are made to coexist to prevent or decrease deposition of radioactive corrosion products to the nuclear fuel rod. A method and a nuclear plant capable of preventing deposition and activation of crud to the nuclear fuel rod and decreasing the radioactivity level in reactor water can be provided.

Method of operating BWR plant, BWR plant and metal element injecting

A radioactive waste liquid treatment apparatus according to the invention comprises an upstream-side filter unit having an inlet for radioactive waste liquid, and a downstream-side filter unit communicating with the upstream-side filter unit and having an outlet for filtrated liquid. Further, the upstream-side filter unit includes first filter member installed therein having active silica for removal of interfacial active agents and oil, whereas the downstream-side filter unit includes second filter member installed therein, and this second filter member has a vapor permeable membrane.

Radioactive waste liquid treatment apparatus

Waste water concentrator and waste water disposal plant

The primary cooling water in a primary cooling water recirculation path of a nuclear power plant is heated and recirculated in the presence of beryllium, and a film of nickel ferrite and/or cobalt ferrite is formed on the surface of pipings and various apparatus and devices connecting with the primary cooling water. The beryllium is injected in the form of beryllium ion into the primary cooling water, or is disposed in the form of beryllium or beryllium-containing alloy in the piping and/or the various apparatus and devices.

Radioactivity reduction method of a nuclear power plant and a nuclear

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.

Method of inhibiting radioactive substances from eluting into cooling

The present invention relates to an apparatus for removing suspended matter, organic matter and nitrogen compounds in the sewage. A processing tank is provided with a floating-separation zone at the upper portion thereof and an electrolysis zone below the floating-separation zone. A bed of porous adsorbent is disposed in the electrolysis zone and electrodes are disposed among the adsorbent. Bubbles generated upon the feed of current to the electrodes rise up through the floating-separation zone to remove the suspended matter and the organic matter in the sewage before introducing the sewage into the electrolysis zone. The porous adsorbent is polarized by the feed of current to the electrodes and results in removing matter remaining in the sewages, especially nitrogen compounds.

Apparatus for treatment of sewage

The present invention relates to a method for removing suspended matter, organic matter, foaming matter and nitrogen compounds in sewage and to an apparatus for the method. The suspended matter and the organic matter are removed by means of first fine bubbles and the foaming matter is removed by means of second bubbles having a larger bubble average diameter. The sewage treated by the first and second bubbles passes through a bed of porous adsorbent polarized by the feed of current, so that nitrogen compounds and the organic matter remained in the sewage are adsorbed and removed. It is also provided with a step for removing the suspended matter and the organic matter remained in the sewage by means of third fine bubbles before transferring the sewage to the bed of adsorbent.

Method for treatment of sewage

Waste water issued from a wet type desulfurization apparatus and containing thionic acid ions is introduced into ion-exchange towers filled with weak-basic anion-exchange which has to effect anion exchange therein. The weak-basic anion-exchange resin which has adsorbed the thionic acid ions is desorbed by contacting an alkaline solution. The thionic acid ions included in the desorbing solution are decomposed by heating them in the presence of acid. A decomposed solution is issued out of the system after its neutralization.

Method of treatment of waste water containing sulfur compounds

A waste flue gas desulfurizing method in which a waste flue gas containing sulfurous acid gas is contacted directly with sea-water, whereby the sulfurous acid gas is absorbed in the sea-water and concurrently sulfites are formed in the sea-water by the reaction between the sulfurous acid ions and metal ions present in the sea-water, and then the carbonic acid component contained in the sea-water which is then in the acidic region is released therefrom by a decarbonation operation to restore the pH value of the sea-water in the neutral region, and thereafter oxygen contained in air or from other source is introduced into the sulfite-containing sea-water to convert said sulfites into sulfates.

Waste flue gas desulfurizing method

A system is provided for separating waste water or solution into a permea solution and a concentrated solution by feeding the waste water or solution to a reverse osmosis apparatus using a membrane. A chemical pretreating apparatus is provided to prevent hard scales contained in the waste water or solution from precipitation during the concentration in the reverse osmosis apparatus using the membrane. An apparatus for charging sponge balls is further provided to mechanically remove suspended solids and other suspended matters, that is, soft scales when deposited on the surface of membrane. The sponge balls are desirably recyclically used.

Apparatus for treating waste water or solution

There are disclosed methods for removing fluorine values from fluorine-containing waste waters, in which aluminum ions are added to fluorine-containing waste water to convert fluorine to hydroxyfluoride complexes, adding phosphoric acid or phosphate and calcium compound are added to form fluoride apatite with residual fluorine in the waste water, and the hydroxy-fluoride complex and fluoride apatite are removed from the waste water. When waste water containing a phosphate in addition to fluorine is treated, the waste water is divided, according to the fluorine concentration, into concentrated waste water having a high fluorine concentration and dilute waste water having a low fluorine concentration; calcium compound is added to the concentrated waste water to form calcium fluoride, aluminum ions are added to the dilute waste water to form a hydroxy-fluoride complex; the so treated dilute waste water is mixed with the phosphate-containing concentrated waste water from which the precipitated calcium fluoride has been removed, calcium compound is added to the mixture to form fluoride apatite, and the hydroxy-fluoride complex and fluoride apatite are removed from the mixed waste water.

Method and apparatus for treatment of fluorine-containing waste waters

A multi-stage distillation plant consisting essentially of a multi-flash evaporator provided with a multi-flash chamber which is divided into a heat recovery section and a heat rejection section. In this multi-stage flash distillation plant, the aforesaid flash evaporator is provided with a deaerator for deaerating cold sea water, a thickener for separating brine containing a relatively great amount of seeds, from concentrated brine which has been extracted from a front chamber of the final stage flash chamber, and a seed mixing tank for obtaining a seed-mixed brine, whereby part of the sea water which has passed through the deaerator is supplied as a feed sea water to the rear chamber of the final stage flash chamber, while the brine containing a relatively great amount of seed and extracted from the thickener is joined to the seed-mixed brine fed from the seed mixing tank. Thus, the confluent brine thus joined together is discharged for deaeration into the final stage flash chamber from a distributor provided in the rear chamber thereof. According to another aspect of the invention, the aforesaid deaerator is omitted and the feed sea water which has not been subjected to deaeration is joined to the aforesaid confluent brine and is discharged for deaeration from the distributor.

Multi-stage flash distillation plant

A vacuum deaerator is provided with a plurality of low pressure chambers disposed in a multi-stage fashion. The pressures in the aforesaid low pressure chambers are so adjusted that the difference between the temperature at treated water which flows into respective low pressure chambers and the temperature in the low pressure chambers may be maintained constant.

Vacuum deaerator

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Hitachi, Japan

Toshio Sawa