Decommissioning method of biodegradable concrete of PWR type nuclear power plant

A decommissioning method of biological shielding concrete of a nuclear power plant, comprising:

• decommissioning a neutron detector positioning device installed in the biological shielding concrete surrounding a nuclear reactor thereby exposing a plurality of penetrated parts in the biological shielding concrete, wherein the plurality of penetrated parts are cavities formed in the biological shielding concrete for accommodating the neutron detector positioning device and therefore pre-exist before decommissioning the neutron detector positioning device, the plurality of penetrated parts being defined by an external surface of the biological shielding concrete;
• inserting a part of a cutting device into the plurality of penetrated parts, wherein, during the inserting, the cutting device directly contacts the external surface of the biological shielding concrete in the plurality of penetrated parts;
• and
• breaking up the biological shielding concrete into a plurality of sub-concrete parts by using the cutting devices, wherein the biological shielding concrete has an inner wall and an outer wall, the penetrated parts extend from the inner wall to the outer wall, the inner wall is curved and the outer wall is flat.