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WM2005 Symposia, Tucson, AZ – February 27-March 2, 2005 Accelerated
Design and Fabrication of a Mobile Drum Vent System for TRU Retrieval
Activities in Hanford 200 West Area Low Level Burial Ground Trenches Terry
Wickland, Nuclear Filter Technology In
2003, Fluor Hanford (FH) was faced with meeting rigorous retrieval milestones
which included removing drums from Hanford 200 Area Low Level Burial Ground
(LLBG) Trenches. The retrieval process requires performing inspections,
radioactive material assay, and venting in preparation for processing
drums containing Transuranic (TRU) waste at the Waste Receiving and Processing
Facility (WRAP). Waste is subsequently
shipped to the WIPP facility in This
paper describes the engineering approach, venting process and hydrogen
concentration analysis, equipment modifications made after system delivery,
operational performance, and some of the managerial tools used to foster
a win-win contracting arrangement. There
are approximately 30,000 drums buried in trenches in the 200 West Area.
Of the 15,000 that are determined to be TRU, it is predicted that
7,000 of them have vent clips, providing sufficient ventilation for transportation
within the 200 West Area and are freely released for processing at WRAP.
The remaining 8,000 TRU drums are expected to require venting and
will be processed through the Mobile Drum Vent System (mDVS). Drum ventilation is performed by installation of filters that are compliant with the Trampact for TRUPACT II requirements. The filters are installed in the TRU waste drum lids and vent hydrogen and other flammable gases while retaining radioactive particles. The waste consists primarily of contaminated debris enclosed in 55-gallon drums, each of which has one or more layers of plastic wrapping and/or a plastic liner inside the drums. The drums are contact handled (<100 mr/hr). When a drum is determined through inspection to be corroded, contaminated, bulged, have physical damage, contain liquids, or unknown contents, the drum is over-packed in an 85-gallon drum. Engineering
Approach The engineering approach to the mDVS is based on NucFil’s experience in the design and fabrication of four other drum vent systems which are in use at various DOE facilities. Two of these systems are in use at Savannah River Site – one for WIPP headspace gas characterization of TRU drums and one for ventilation of low activity drums with Pu-238 contaminated waste. One system is at the Nevada Test Site performing ventilation and WIPP headspace gas characterization of TRU drums, and one system is at the INEEL Advanced Mixed Waste Treatment Plant performing ventilation and WIPP headspace characterization of legacy TRU drums. Several major differences arose from the previous four systems, driven by cost and schedule constraints, as well as mission requirements, and new design ideas. An effort was made to simplify the inputs required from a programmable logic control (PLC) and a simpler hydraulic oil over air linear drive system was designed. A second difference was one that emphasized controlling deflagration gases as opposed to isolating deflagration gases in a chamber rated for containing pressure up to 15 PSI. The system also incorporated the capability to vent 30-gallon drums, and 85-gallon drums with restraints without changing software. It also provides a conveyor system to accommodate venting up to six drums without reloading the drums.
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