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

WIPP RH PSAR DOE/WIPP-03-3174 CHAPTER 4
4.2.2.2 Shaft and Hoist General Features
The principal components of each shaft are the shaft collar (extending from above the ground surface to
the top of the bedrock), the shaft lining (extending from the bottom of the collar to the top of the salt
formation at about 850 ft (259 m) below the surface), and the key section that terminates the lining in the
salt formation, with the remainder of each shaft being unlined.
The shaft collars are situated about 400 ft (122 m) above the historic flood plain of the Pecos River and
the collar slab around the shaft, where used, is at a higher elevation than the surrounding ground.
The waste shaft, the SH shaft, and the AIS are equipped with conveyances with hoist towers constructed
of structural steel. The conveyances in the waste shaft and AIS are guided by steel cables (guide ropes),
while the SH shaft conveyance is guided by fixed wooden guides equipped with safety dogs. The waste
shaft is equipped with catch sprags in the hoist tower to prevent the conveyance or the counterweight
from falling into the shaft if the conveyance over-traveled against the upper crash beam and the hoist
ropes failed.
The waste hoist and SH hoist have redundant brake systems designed so that either set of brakes can stop
a fully-loaded conveyance under all conditions. In the event of a power failure, the brakes will set
automatically. The AIS hoist is also equipped with two sets of brakes.
The control system for each hoist can detect malfunctions or abnormal operations (such as over-travel,
over-speed, power loss, circuitry failure, or starting in a wrong location), trigger an alarm for the
abnormal operation, and automatically shut down the hoist.
4.2.2.3 Shaft and Hoist Specific Features
The main purpose of the waste hoist system is for moving radioactive waste from the surface to the
underground. The system can be used to remove radioactive waste from the disposal area if required. It
is also used to transport personnel, material and equipment. The system supports maintenance in the
waste shaft. The equipment that is part of this system is the waste hoist equipment installed in the
WHB, the headframe, shaft switches, and the conveyance. The hoist systems in the shafts and all shaft
furnishings are designed to resist the dynamic forces of the hoisting operations (these forces are greater
than the seismic forces on the underground facilities). In addition, the waste hoist headframe is designed
to withstand a DBE (the DBE is defined in Section 3.2.7). The waste hoist is equipped with a control
system that will detect malfunctions or abnormal operations of the hoist system (such as
over-travel, over-speed, power loss, circuitry failure, or starting in a wrong direction), will trigger an
alarm for that condition and automatically shut down the hoist. The waste shaft and hoist arrangement is
shown on Figure 4.2-31.
The inside diameter of the unreinforced concrete-lined upper portion of this shaft is 19 ft (5.8 m). The
waste hoist conveyance (outside dimensions) is approximately 30 ft (9.15 m) high by 11 ft (3.35 m) wide
by 15 ft (4.6 m) deep, and carries a maximum payload of 45 tons. The conveyance contains an upper and
lower deck. During loading and unloading operations, the conveyance is steadied by fixed guides. At
the underground waste hoist station, rope stretch is removed by a chairing device that supports the weight
of the conveyance and payload.
4.2-22 January 28, 2003