The present invention relates to a wire saw excavation apparatus that is installed on a plurality of entry holes, where the plurality of entry holes are drilled according to a cutting section of a target surface of rock to be excavated so that the target surface is excavated by using wire saws. The wire saw excavation apparatus mounts N number of pulleys on one entry arm to cut the rock in N number of directions all at once.

The present invention relates to a gravity based structure 5 with a topside 2 on at least one hollow concrete platform leg 1 with a platform leg wall and a circular cross section. The at least one platform leg, includes an upper leg portion (4) cut off from a lower leg portion 3. The lower leg portion 3 has an upper sloped cut surface 10 inclined at an angle in the range of 1°-10° off a horizontal axis. The upper leg portion 4 has an upper leg sloped cut surface inclined at the same angle as the lower leg sloped cut surface 10 of the lower leg portion 3 whereby the angles are complementary, the sloped cut surfaces forming an inner and an outer obtuse cone with a common vertical longitudinal axis. Furthermore, the invention relates to method of forming a conical cut through a concrete platform leg of a GBS.

A method for complex-decommissioning a nuclear facility is disclosed. The method for complex-decommissioning the nuclear facility includes: cutting and expanding an inner wall of the cavity; installing a cutting device that cuts and decommissions the nuclear reactor pressure vessel inside the cavity; fixing the nuclear reactor pressure vessel inside the cavity by using a fixture; and cutting and decommissioning the nuclear reactor pressure vessel fixed inside the cavity by using a cutting device.

The present invention relates to a wire saw excavation apparatus that is installed on a plurality of entry holes drilled according to a cutting section of a target surface of rock to be excavated so that the target surface is excavated by using wire saws, and more particularly, to a wire saw excavation apparatus that mounts N pulleys on one entry arm to cut the rock in N directions all at once, thereby remarkably improving the work efficiency.

A decommissioning method of biological shielding concrete of a nuclear power plant according to an exemplary embodiment includes: decommissioning a neutron detector positioning device installed to biological shielding concrete surrounding a nuclear reactor to form a plurality of penetrated parts in the biological shielding concrete; inserting a part of a cutting device into the plurality of penetrated parts; and decomposing the biological shielding concrete into a plurality of sub-concrete parts by using the cutting device.

A wire saw includes a saw wire forming a sawing section for engagement with a workpiece to be cut. A guide is arranged to position the sawing section of the saw wire relative to the workpiece. The guide is configured to permit a plurality of independent directions of movement such that, in addition to an advance of the sawing section in the direction of the workpiece to be cut, the sawing section can be lengthened and/or shortened. A wire-storage-and-tensioning device is arranged for loading, unloading, and tensioning the saw wire when a position and/or a length of the sawing section is changed by the guide. The guide has, for each of the plurality of independent directions of movement, a separate wire storage associated with the given individual direction of movement.

A decommissioning method of biodegradable concrete of a nuclear power plant according to an exemplary embodiment includes: decommissioning a neutron detector positioning device installed to biodegradable concrete surrounding a nuclear reactor to form a plurality of penetrated parts in the biodegradable concrete; inserting a part of a cutting device into the plurality of penetrated parts; and decomposing the biodegradable concrete into a plurality of sub-concrete parts by using the cutting device.

The present invention relates to a gravity based structure 5 with a topside 2 on at least one hollow concrete platform leg 1 with a platform leg wall and a circular cross section. The at least one platform leg, includes an upper leg portion (4) cut off from a lower leg portion 3. The lower leg portion 3 has an upper sloped cut surface 10 inclined at an angle in the range of 1-10 off a horizontal axis. The upper leg portion 4 has an upper leg sloped cut surface inclined at the same angle as the lower leg sloped cut surface 10 of the lower leg portion 3 whereby the angles are complementary, the sloped cut surfaces forming an inner and an outer obtuse cone with a common vertical longitudinal axis. Furthermore, the invention relates to method of forming a conical cut through a concrete platform leg of a GBS.

The present invention relates to a wall structure cutting wire saw. The wire saw includes a master saw unit 12 with master rail elements 35 adapted to run on a first set of tracks 7. The master saw unit 12 includes a wire drive motor 18, a wire magazine 17 accommodating a portion of a of cutting wire 15 in a cutting wire loop, and a saw drive 11 adapted to drive the master saw unit 12 along the first set of tracks 7. The master saw unit also includes a wire tension actuator. A slave unit 13 with at least one slave wire return wheel 23 and slave rail elements 36 is adapted to run on a second set of rails 8. The invention further includes a first set of rails adapted to be secured to a first side of the wall structure; and a second set of rails adapted to be secured to a second side of the wall structure 33. The wall structure 33 may form a wall of a GBS leg.

A wire saw apparatus comprises: a first pulley system from which a wire is withdrawn toward a structure to be cut; a second pulley system into which the wire is introduced from the structure; a first dust collection pipe unit provided to surround the wire between an end part at which surrounding of the structure by the wire ends and a part at which the wire is introduced into the first pulley system; and a second dust collection pipe unit provided to surround the wire between a start part at which surrounding of the structure by the wire starts and a part at which the wire is withdrawn from the second pulley system.