Heat transfer tube repairing apparatus and method and steam generator

A heat transfer tube repairing method comprising:

• inserting a flexible cord-like member into a heat transfer tube;
• positioning a repairing member provided at a predetermined position in the longitudinal direction of the cord-like member to a position facing a damaged portion in the heat transfer tube;
• and
• pressing the repairing member against inner surfaces at the front and rear sides of the damaged portion of the heat transfer tube.

A steam generator comprising:

• a cylinder portion that is formed in a hermetic hollow shape;
• a heat transfer tube bundle that includes a plurality of heat transfer tubes which are disposed inside the cylinder portion so as to form a reverse U-shape and through which primary cooling water flows;
• a tube sheet that is fixed to a lower portion inside the cylinder portion and supports end portions of the plurality of heat transfer tubes;
• an entrance side channel head and an exit side channel head that are provided at the lower end portion of the cylinder portion and communicate with the respective end portions of the plurality of heat transfer tubes;
• a water feeding portion that supplies secondary cooling water into the cylinder portion;
• a steam outlet that is provided at the upper end portion of the cylinder portion;
• and
• a heat transfer tube repairing member that is pressed and held on inner surfaces at the front and rear sides of a damaged portion of the heat transfer tube.