METHOD FOR DISMANTLING STEAM GENERATOR - MITSUBISHI HEAVY IND LTD

Title:

METHOD FOR DISMANTLING STEAM GENERATOR

Document Type and Number:

WIPO Patent Application WO/2023/053555

Kind Code:

A1

Abstract:

A method for dismantling a steam generator is provided, the steam generator comprising: a trunk portion; a water chamber; a tube plate that is provided between the trunk portion and the water chamber to define a primary region on the water chamber side and a secondary region on the trunk portion side, and is formed with a plurality of through-holes penetrating therethrough in a thickness direction; and a plurality of heat transfer tubes inserted into the plurality of through-holes. The method comprises: a step for obtaining an object to be dismantled, including the tube plate and a part of the heat transfer tubes, by cutting end surfaces of the heat transfer tubes and the tube plate on the primary region side of the tube plate and cutting the heat transfer tubes so as to project from the tube plate on the secondary region side thereof; a step for identifying a heat transfer tube fixed to the tube plate among the heat transfer tubes included in the object to be dismantled; a step for inserting a TIG heating head into the part of the heat transfer tube fixed to the tube plate and heating the heat transfer tube to release the fixation between the part of the heat transfer tube and the tube plate; and a step for pulling out the part of the heat transfer tube from the through-hole. In the step for releasing the fixation, the TIG heating head is inserted from the primary region side, and in the step for releasing the fixation, the TIG heating head is moved in a plurality of lines, only in a direction from the primary region side toward the secondary region side along a longitudinal direction inside the part of the heat transfer tube.

Inventors:

UENO REIKO (JP)
YAMAMOTO TAKESHI (JP)
KOBAYASHI YUKI (JP)
HARA DAISUKE (JP)
NODA MASAKI (JP)
TADA KOHEI (JP)

Application Number:

PCT/JP2022/018888

Publication Date:

April 06, 2023

Filing Date:

April 26, 2022

Export Citation:

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Assignee:

MITSUBISHI HEAVY IND LTD (JP)

International Classes:

B23P21/00; F22B37/58; F28F11/00

Foreign References:

JPS5592801A	1980-07-14
JPS61213404A	1986-09-22
JPS5412002A	1979-01-29
JP2004069107A	2004-03-04
JP2012189247A	2012-10-04
JP2003251536A	2003-09-09
JP2021159780A	2021-10-11
JPH0718531B2	1995-03-06

Other References: