Tendon Gallery and Annulus Maintenance Access

This structure is located at the 214° azimuth, it consists of a vertical shaft extending from grade at El 646.0 down to the horizontal passageways which enter the annulus at El 620.0 and the tendon gallery at El 606.5, respectively. 

Steel ladders with safety devices shall extend between horizontal levels and the shafts can serve as a work access to the tendon gallery during tendon installation. After tendon installation a removable structural steel floor at El 620.0 has been installed to provide access to the annulus. The annulus access can be used to bring in the tendon jacks during surveillance testing. The surveillance tests will be performed at one year intervals for the first three years of plant life and at five year intervals thereafter. The annulus access can also serve as the maintenance access for servicing various mechanical systems located in the annulus. 

Due to the infrequent use of the access structure, the top cover slab at El 646.25 has been bolted into place and will have lifting eyes such that it can be removed with a small mobile hoist. 

The removable floor at El 620.0 shall have a man-hatch to provide access to the tendon gallery for inspection purposes. If it becomes necessary to take large tools or parts into the tendon gallery, the steel floor at El 620.0 may be lifted out to grade. 

This structure has been connected to the tendon gallery by construction joints below El 620.0. Above El 620.0, an expansion joint shall be used, to allow independent, movement of this structure and the secondary containment during earthquake. 

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