NOVELTY - Soundness evaluation method of fuel gas flow channel of solid oxide fuel cell is performed by analyzing (S1) methane-containing gas which does not contain water vapor by gas chromatography, mixing (S2) methane-containing gas and water vapor to create gas for reaction, discharging (S3) off gas from fuel gas discharge part of fuel electrode, removing (S4) water vapor from off gas, computing (S6) component amount of gas for reaction, computing (S7) component amount of the off gas by implementing mass-balance calculation, and determining (S8) reaction condition of methane in fuel electrode.    USE - Soundness evaluation method of fuel gas flow channel of a solid oxide fuel cell.    ADVANTAGE - Structure of fuel gas flow channel of solid oxide fuel cell can be appropriately evaluated, and design of fuel gas flow channel can be attained based on the evaluation result.    DETAILED DESCRIPTION - Soundness evaluation method of fuel gas flow channel of solid oxide fuel cell is performed by analyzing methane-containing gas which does not contain water vapor by gas chromatography, mixing methane-containing gas and water vapor to create gas for reaction, discharging off gas from fuel gas discharge part of fuel electrode which supplies gas for reaction to fuel gas introduction part of fuel electrode including the fuel gas flow channel of solid oxide fuel cell, removing water vapor from off gas to create off gas for analysis, conducting gas chromatographic assay of component amount of the off gas, computing component amount of gas for reaction from component amount of methane-containing gas and water vapor content rate of gas for reaction, computing component amount of the off gas by implementing mass-balance calculation which considers chemical reaction which arises in the fuel electrode which includes the fuel gas flow channel using the component amount of gas for reaction and the component amount of the off gas for analysis, and determining reaction condition of methane in fuel electrode including the fuel gas flow channel using component amount of gas for reaction and component amount of the off gas. INDEPENDENT CLAIMS are included for:    (1) soundness evaluation apparatus of fuel gas flow channel of a solid oxide fuel cell comprising unit for reading component amount of the off gas for analysis acquired from off gas discharged from fuel gas discharge part of fuel electrode including the fuel gas flow channel by conducting gas chromatographic assay of the off gas for analysis from which water vapor is removed and water vapor content rate of gas for reaction from a memory device and unit for calculating reaction condition of methane in a fuel electrode including the gas flow channel; and    (2) soundness evaluation program of fuel gas flow channel of a solid oxide fuel cell comprising computer with a unit for reading component amount of the off gas for analysis and water vapor content rate of gas for reaction from memory device and unit for calculating reaction condition of methane in a fuel electrode including the fuel gas flow channel.    DESCRIPTION OF DRAWING(S) - The drawing shows a flowchart of the soundness evaluation method. (Drawing includes non-English language text).    Gas chromatography analysis of methane-containing gas (S1)    Mixing of methane-containing gas and water vapor (S2)    Discharge of off gas from fuel gas discharge part of fuel electrode (S3)    Removal of water vapor from off gas (S4)    Gas chromatographic assay of component amount of the off gas (S5)    Calculation of component amount of gas for reaction (S6)    Calculation of component amount of the off gas by implementing mass-balance calculation (S7)    Determination of reaction condition of methane in fuel electrode (S8)