DOE 2000. - Waste Isolation Pilot Plant - U.S. Department of Energy

WIPP RH PSAR DOE/WIPP-03-3174 CHAPTER 4
Transfer Carriage
The transfer carriage (Figure 2.4-25) is a large steel shield cylinder with its own hydraulic system that is
used to push either the waste canister from the facility cask into the borehole or the shield plug from the
shield plug carriage into the borehole.
The rear end of the transfer carriage houses the transfer mechanism and includes heavy wall shielding to
prevent exceeding radiation dose rate limits when the facility cask top shield valve is opened. The
transfer carriage housing is a steel cylinder 91.25 in (231.8 cm) long, 30 in (76.2 cm) inside diameter.
The hydraulic drive system components which operate the transfer mechanism are mounted in or on the
transfer carriage housing. The transfer mechanism and grapple are used to emplace the waste canister
and shield plug into the borehole.
The transfer carriage has roller bearings which ride on the rails on the staging platform. The transfer
carriage drive system, which positions the front of the housing against the facility cask during waste
canister emplacement, is mounted on the staging platform. During shield plug emplacement, the transfer
carriage is retracted to provide room for installing the shield plug carriage on the staging platform.
Its transfer mechanism consists of a double acting five stage, telescopic, hydraulic cylinder attached at
the plunger end of the transfer carriage housing end plate. The front end of the cylinder is supported by
two rollers attached to a 2.75 in (7.0 cm) thick steel plate which provides shielding and supports the
grapple. The hydraulic cylinder has a 10,000 lbs min. load capacity, a 24 ft (7.3 m) stroke, and a
retracted length of 70 in (178 cm). If a power failure occurs, manual means are provided to retract the
transfer mechanism from a partial or fully extended position and to release the grapple.
The transfer carriage is equipped with four locking clamps to clamp the carriage to both the facility cask
and shield plug carriage.
The following position sensors are mounted on the transfer carriage:
Two spring-loaded reel type mechanisms attached to multi-turn rotary potentiometers monitor the travel
distance of the transfer carriage.
Three proximity metal detecting switches that activate and indicate when the transfer carriage to facility
cask gap is less than 0.125 in (0.318 cm).
Two grapple mounted proximity detection switches to detect when the grapple comes in contact with the
pintle of the waste canister or shield plug.
Shield Plug Carriage
The shield plug carriage (Figure 4.2-26) is a 74 in (188 cm) long, 0.5 in (1.27 cm) thick saddle which
holds the shield plug in a horizontal position during emplacement and aligns the bottom of the shield
plug with the bottom of the facility cask cavity. The shield plug carriage is placed on and supported by
the rails of the staging platform. The shield plug carriage has two forklift pads to facilitate handling by a
forklift.
4.2-17 January 28, 2003