Lower-portion component attaching and detaching apparatus and use method of lower-portion component attaching and detaching apparatus

A use method of a lower-portion component attaching and detaching apparatus for attaching and detaching a spool piece possibly included in a control rod drive mechanism that drives a control rod, to and from a main unit of the control rod drive mechanism,

• the lower-portion component attaching and detaching apparatus including
• a raising and lowering mechanism that raises and lowers the spool piece by expansion and contraction of a plurality of fluid pressure cylinders, and
• a pushing-up mechanism that pushes up and holds the spool piece at a height at which attachment of the spool piece to the main unit of the control rod drive mechanism is possible, in a case in which the raising and lowering mechanism is incapable of holding the spool piece at the height,
• the use method comprising:
• pushing up and holding the spool piece at the height by the pushing-up mechanism in a case in which the raising and lowering mechanism is incapable of raising and holding the spool piece at the height in order to attach the spool piece to the main unit of the control rod drive mechanism;
• and
• attaching the spool piece to the main unit of the control rod drive mechanism.