Methods and apparatus for decontaminating disposable protective products prepared from polyvinyl alcohol (PVA), used in a nuclear power plant, to less than minimum detectable activity (MDA) are disclosed. In the disclosed methods and apparatus, solid protective products made of PVA, generated from a nuclear power plant, are dissolved into a liquid, and then are decontaminated to less than MDA. The PVA solution decontaminated in this way is concentrated to an appropriate concentration or dried, and finally is subjected to self-disposal. This can fundamentally block the generation amount of combustible waste amounting to 50% or more of low and intermediate level waste of nuclear power plants, thereby considerably contributing to a reduction of the operating expenses of the nuclear power plants. The present invention further relates to methods and apparatus for self-disposing disposable protective products manufactured by conventional polyvinyl alcohol (PVA) through pyrolysis/catalytic oxidation of a PVA solution generated by concentration, and treating the decontaminated PVA solution within a plant. The PVA protective products are dissolved/concentrated/oxidized in water to remove firstly organic matter, and then PVA materials in the PVA solution are completely oxidized into CO2 and H2O by using a small-sized pyrolysis/catalytic oxidation reactor.