NOVELTY - A bio-reaction tank (16) comprises microorganism cultivation chip and/or microorganism culture solution. A pump (18) feeds organic type radioactive liquid waste from storage tank (10) into the bio-reaction tank. A stirring and heating apparatus (12,14) attached to the reaction tank performs stirring of mixture of liquid waste and microorganism. The liquid waste is decomposed by the microorganism and converted to harmless gas. An oil trap unit (20) connected with gas monitor (22) is provided at exhaust system of the reaction tank.    USE - For decomposition processing or organic type radioactive liquid waste such as tributyl phosphate dedecane waste liquid from nuclear fuel reprocessing facility, organic-type radioactive liquid waste containing polychlorinated biphenyl (PCB), liquid scintillator waste liquid, machine oil and engine oil of car.    ADVANTAGE - The radioactive liquid waste of organic mater is decomposed by microorganisms and converted into harmless gas within bio-reaction tank and so, the radioactive liquid waste can be decomposed efficiently. An oil trap unit and decomposition gas monitor unit are provided at exhaust system of bio-reaction rank and so, leakage of radioactive substance and toxic substance from bio-reaction tank is prevented.    DETAILED DESCRIPTION - A bio-reaction tank (16) comprises microorganism cultivation chip and/or microorganism culture solution. A pump (18) feeds organic type radioactive liquid waste from storage tank (10) into the bio-reaction tank. A stirring and heating apparatus (12,14) attached to the reaction tank performs stirring of mixture of liquid waste and microorganism. The liquid waste is decomposed by the microorganism and converted to harmless gas. An oil trap unit (20) connected with gas monitor (22) is provided at exhaust system of the reaction tank. The organic type radioactive substance liquid waste decomposition apparatus has bio-reaction tank containing microorganism such as aerobic microbes for decomposing the waste liquid into harmless gas. A gas monitor monitors amount harmless gas obtained during bio reaction of liquid waste at the tank.    An INDEPENDENT CLAIM is also included for radioactive liquid waste decomposition processing method involves introducing radioactive liquid waste into bio-reaction tank containing microorganism cultivation chip and/or microorganism solution. The introduced liquid waste is mixed with microorganism in proper weight ratio. The liquid waste from storage is fed gradually into the reaction tank according to advance of decomposition of radioactive liquid waste. The microorganism chip or solution inside the reaction tank is replaced until the residue in the reaction tank reaches constant quantity and residue is removed off when constant quantity is reached.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic drawing of the organic type radioactive waste decomposition processing apparatus. (Drawing includes non-English language text)    Waste liquid storage tank (10)    Stirring apparatus (12)    Heating apparatus (14)    Bio-reaction tank (16)    Pump (18)    Oil trap unit (20)    Decomposition gas monitor (22)