| 摘要 |
A nuclear steam generator modularized wrapper assembly comprising at least two separate generally cylindrical wrapper modules with tube support plates therewithin are assembled in stacked relation and joined within the nuclear containment building, the assembled modules then being placed in the shell with the tube apertures in the tube support plates being aligned with the tube apertures in the tube sheet, and a plurality of adjustable spacer means fixed to the outer circumference of the wrapper assembly are provided and are adjusted to vary the width of the space in the annulus between the wrapper and shell at various locations to lock the assembly in place with axial alignment of all of the apertures in the tube support plates and tube sheets. The method of effecting the replacement of a wrapper assembly in the field within the nuclear containment building includes providing tube aperture keying means at selected locations on the upper surface of the tube sheet to promote alignment of all the tube apertures in the various parts, the keying means being removed after the adjustment of the spacer means in the annulus. |
