Abstract: A fuel cell stack and fuel cell modules that constitute such a fuel cell stack are provided, wherein adhesion of foreign materials to an electrolyte membrane of each fuel cell can be effectively prevented, and highly efficient maintenance is possible by replacing a fuel cell with degraded performance out of the fuel cell stack. A plurality of fuel cells 10 each having a membrane electrode assembly 1, gas-permeable layers 2,3,5,6 on the anode and cathode sides, sandwiching the membrane electrode assembly 1 therebetween, and a separator 7 on at least one of the anode and cathode sides are stacked. A gasket 8 is integrally molded with peripheral edges of the membrane electrode assembly 1 and the gas-permeable layers 2,3,5,6 of each of the stacked cells, whereby a single fuel cell module 100 is formed. Stacking and compressing such modules 100, . . . can form a fuel cell stack.

Abstract: The method of manufacturing a fuel cell including stacked unit cell constituent members sandwiched by separators includes the steps of arranging the unit cell constituent member in a first area on a first face of the separator; and forming a seal member made of elastic material such that the seal member is adhered or intimately attached to a second area including the first area on the first face of the separator, and that the seal member is unified with an edge portion of the unit cell constituent member.

Abstract: A fuel cell including separators opposing each other and squeezing a power generating reaction portion. Each of the separators includes a gas passage, a gas passage dividing rib, and a protrusion formed in the gas passage. In a first separator, which is an at least one separator of the separators opposing each other via the power generating reaction portion, at a region of the first separator opposing a gas passage dividing rib of a second separator, which is a separator opposing the first separator, a squeezing rib is formed and replaces the protrusion. The squeezing rib and the gas passage dividing rib of the second separator squeezes the power generating reaction portion. At the region of the first separator, a contact area of the squeezing rib with the power generating reaction portion is adapted to be larger than a contact area of the protrusion of the first separator with the power generating reaction portion in a case where the protrusion were formed without forming the squeezing rib.

Abstract: A membrane electrode assembly according to the invention includes a solid polymer electrolyte membrane and an electrode joined to each of two sides of the solid polymer electrolyte membrane. The solid polymer electrolyte membrane is such that some or all of the protons included in the entire solid polymer electrolyte membrane, a band region, or a non-power generating region are ion exchanged with one or more cations selected from among complex cations, class four alkylammonium cations, and high valence cations. In addition or alternatively, the solid polymer electrolyte membrane includes an organo-metalloxane polymer obtained by impregnating the entire solid polymer electrolyte membrane, the non-power generating region, or the band region with an organo-metalloxane monomer that includes an ammonium cation or a class four ammonium cation at its terminus and then hydrolyzing and polycondensing the organo-metalloxane monomer.

Abstract: A fuel cell module, wherein slopes of a same angle ? relative to a bottom face are formed on both side faces to form a recessed groove in a tapered shape. Since the angle ? is provided to the side faces of the recessed groove, the exhaustion of gases from the accumulation of gasses to the outside can be assisted by the side faces with the angle ? more than in a case where the side faces of the recessed groove are formed in right angled shapes even if the accumulation of gases is produced between an adhesive agent and the inner surfaces of the recessed groove when first and second separators are joined to each other for modularization by covering the first separator on the second separator. Thus, the accumulation of the gases can be prevented from occurring.

Abstract: A fuel cell stack includes: a first cell having a first fuel gas flow path; and a second cell having a second fuel gas flow path constructed to have a specific flow path structure having a higher potential for a decrease in concentration of a fuel gas than that of the first fuel gas flow path during power generation. A sensor is located on the second cell to detect a decrease in concentration of the fuel gas during power generation. In one exemplified structure, a groove formed on an anode separator of the second cell as the second fuel gas flow path has a restriction element to narrow the sectional area of flow passage. A hydrogen concentration sensor is located in a non-narrowed area in the downstream of the restriction element having a lower pressure level. Impurity gas discharge control discharges an anode off gas out of the fuel cell stack, in response to detection of a decrease in hydrogen concentration to or below a preset reference level by the hydrogen concentration sensor.

Abstract: A fuel cell is formed by alternately stacking separators and sealing gasket-combined membrane electrode assemblies. Each sealing gasket-combined membrane electrode assembly includes a membrane electrode assembly and a sealing gasket portion. One of the sealing gasket portion and the separator has a protrusion formed on each face and extending in a stacked direction in which the separators and the sealing gasket-combined membrane electrode assemblies are stacked. The other of the sealing gasket portion and the separator has a recess in which the protrusion is fitted. The protrusions formed respectively on opposed faces of the successive sealing gasket-combined membrane electrode assemblies or the successive separators are located at different positions.

Abstract: A fuel cell includes: a membrane electrode assembly provided with an electrolyte membrane and gas diffusion electrodes attached to both sides of the electrolyte membrane; separators supporting the membrane electrode assembly from both sides thereof; a gas flow path forming member disposed between the separator and the gas diffusion electrode to form gas flow path for supplying reactant gas for power generation in the fuel cell to the gas diffusion electrode; and an elastic member disposed between the separator and the gas flow path forming member and having an elastic modulus which is higher than that of the gas flow path forming member.

Abstract: A fuel cell includes a membrane-electrode assembly that has an electrolyte membrane and electrodes, a seal portion formed integrally with an outer peripheral portion of the membrane-electrode assembly, gas separators sandwiching the seal portion from both sides, and gas channel-forming portions each made of a porous body which are disposed between the membrane-electrode assembly and the gas separators. The seal portion includes, as projections that are provided on at least one of the two sides thereof and that contact an adjacent gas separator, a first linear projection surrounding the gas channel-forming portions, and a gas stopper projection which is provided at such a position between the first linear projection and the outer periphery of the gas channel-forming portions as to inhibit the gas flow that passes around the gas channel-forming portions, and which is lower in height than the first linear projection.

Abstract: A seal gasket-integrated membrane-electrode assembly includes: a power generation portion that undergoes electrochemical reactions between hydrogen and oxygen; and a seal gasket provided on an outer peripheral edge of the power generation portion. The first center in the thickness direction of the power generation portion is offset toward an anode electrode of the membrane-electrode assembly from the second center in the thickness direction of the seal gasket.

Abstract: A fuel cell module, wherein slopes of a same angle ? relative to a bottom face are formed on both side faces to form a recessed groove in a tapered shape. Since the angle ? is provided to the side faces of the recessed groove, the exhaustion of gases from the accumulation of gasses to the outside can be assisted by the side faces with the angle ? more than in a case where the side faces of the recessed groove are formed in right angled shapes even if the accumulation of gases is produced between an adhesive agent and the inner surfaces of the recessed groove when first and second separators are joined to each other for modularization by covering the first separator on the second separator. Thus, the accumulation of the gases can be prevented from occurring.

Abstract: A fuel cell including separators opposing each other and squeezing a power generating reaction portion. Each of the separators includes a gas passage, a gas passage dividing rib, and a protrusion formed in the gas passage. In a first separator, which is an at least one separator of the separators opposing each other via the power generating reaction portion, at a region of the first separator opposing a gas passage dividing rib of a second separator, which is a separator opposing the first separator, a squeezing rib is formed and replaces the protrusion. The squeezing rib and the gas passage dividing rib of the second separator squeezes the power generating reaction portion. At the region of the first separator, a contact area of the squeezing rib with the power generating reaction portion is adapted to be larger than a contact area of the protrusion of the first separator with the power generating reaction portion in a case where the protrusion were formed without forming the squeezing rib.

Abstract: In a chemical decontamination method of chemically decontaminating radioactive nuclides from a metallic material, oxalic acid and hydrazine are injected as a reductive decontaminating agent into water that is in contact with the metallic material. Injection of the hydrazine is stopped after a cation resin arranged in a circulation line connected to the metallic material breaks, and at least the oxalic acid and the hydrazine in the reductive decontaminating agent are decomposed using a decomposing catalyst.

Abstract: In a chemical decontamination apparatus, a catalyst decomposition column in an upstream side of an ion exchange resin column and a hydrogen peroxide injection apparatus in a further upstream side, reduce the amount of waste products caused by a chemical decontaminating agent where a mixed decontaminating agent for a composition trapped in a cation resin column and for a composition trapped in an anion exchange resin are used for the chemical decontaminating agent, selectively decompose the composition trapped in the cation resin column in an inlet side of a cleaning apparatus when radioactive nuclides in the decontaminating agent are cleansed using the cation resin column during decontamination, and decompose both compositions after completion of the decontamination. The chemical decontamination thus selectively decomposes the chemical decontaminating agent, which is a component of the load to the cation resin column.

Abstract: To suppress a decrease of thickness due to corrosion of structural members and to achieve a removal of radionuclides with good efficiency in a nuclear power plant, oxidation decontamination is first conducted. An aqueous potassium permanganate solution is supplied from a circulation line to a reactor pressure vessel, which is a stainless steel structural member, and a reactor water cleanup system piping and a drain piping, which are carbon steel structural members. These structural members are oxidation-decontaminated by the action of potassium permanganate. Then the above-mentioned structural members are reduction-decontaminated by using an aqueous oxalic acid solution. The aqueous oxalic acid solution contains hydrazine.

Abstract: [Processes of reductive decontamination using an agent containing at least two kinds of components, and then decomposing the agent using an apparatus for decomposing at least two kinds of chemical substances in the agent, are employed in chemical decontamination.

Abstract: In a chemical decontamination method and a chemical decontaminating system for chemically decontaminating radioactive nuclides from a metallic material surface contaminated by the radioactive nuclides, the method comprise the processes of reductively decontaminating using a reductive decontaminating agent containing at least two kinds of components; and then decomposing the reductive decontaminating agent using a decomposing apparatus for decomposing at least two kinds of chemical substances in the reductive decontaminating agent.

Abstract: Processes of reductive decontamination using an agent containing at least two kinds of components, and then decomposing the agent using an apparatus for decomposing at least two kinds of chemical substances in the agent, are employed in chemical decontamination. A catalyst decomposition column in an upstream side of an ion exchange resin column and a hydrogen peroxide injection apparatus in a further upstream side, reduce the amount of waste products caused by a chemical decontaminating agent where a mixed decontaminating agent for a composition trapped in a cation resin column and for a composition trapped in an anion exchange resin are used for the chemical decontaminating agent, selectively decompose the composition trapped in the cation resin column in an inlet side of a cleaning apparatus when radioactive nuclides in the decontaminating agent are cleansed using the cation resin column during decontamination, and decompose both compositions after completion of the decontamination.