Tank Waste Retrieval, Processing, and On-site Disposal at Three Department of Energy Sites Final Report (2006) / Chapter Skim
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Appendix G Tank Waste Retrieval Techniques and Experience at West Valley and Oak Ridge
Appendix G Tank Waste Retrieval Techniques and Experience at West Valley and Oak Ridge
Pages 163-182
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From page 163... ...
The Savannah River Site has used roof) above the waste to wash radioactive material onto the rotary spray jets (Tank 16)
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From page 164... ...
A jointed arm or mast that is installed through the tank retrieval to retrieve residual waste and may use it for bulk riser and maneuvered to access various portions of the waste retrieval in tanks where leakage becomes a problem. inside of a tank by human control; 2.
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From page 165... ...
hydraulically mobilize and collect wastes (e.g., the "water brush" used at the Savannah River Site, or mechanically To date the dominant deployment technology for tools mobilize and collect waste by acting as a mini-bulldozer (see used to retrieve residual wastes has been mechanical arms. Figure G-4)
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From page 166... ...
(2003) conducted laboratory oxalic acid dissolution testing Previous Savannah River Site experience indicates that on sludge from Savannah River Site Tank 8 to evaluate the using oxalic acid can be effective at removing some residual downstream impacts.
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From page 167... ...
Cost Of Using Oxalic Acid 4This cost estimate includes removal of existing equipment (old waste removal pumps, jets, etc., that occupy risers that are necessary for access) , DOE's estimate for oxalic acid washing in 1999 was purchase and installation of new pumps and other equipment, and upgrades $1,050,000 per tank, including disposal costs at the Savannah to the design safety analyses.
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From page 168... ...
In the case of the oxalic acid used on Tank C-106, oxalate solids were formed that now must be removed by ultrafiltra- TECHNOLOGY ADVANCES FOR MECHANICAL tion in the Waste Treatment Plant. The ultrafiltration system RESIDUAL WASTE RETRIEVAL is a bottleneck in the Waste Treatment Plant due to the filters being used for several operations (e.g., sludge washing, oxi- Pulsating Mixer Pump Technology dative leaching)
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From page 169... ...
slurry vessel where it is then pumped from the tank. The Fluidic technology can be used for bulk waste as well as articulated mast is fitted with a vacuum head, vacuum pump, residual waste retrieval and for mixing the grout with waste slurry vessel, and slurry transfer pump (the same type of residuals that cannot be further removed.
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From page 170... ...
success: The LDUA used at Idaho was able to deploy multiple tools within its reachable workspace but had sig Recalcitrant Waste Deposits nificant downtime due to hardware failures. Since this demonstration, DOE sites have used simpler mechanical arms Waste may be encrusted on internal tank surfaces or for residual waste retrieval as described previously.
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From page 171... ...
Based on experience at the · Tank top loading is limited Savannah River Site and Hanford, chemical cleaning using · All transfers out of the tanks are from one riser location oxalic acid is moderately successful at best. Savannah River · Tank support columns produce shadowing effects is also considering using nitric or hydrofluoric acid to (all sites)
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From page 172... ...
SOURCE: DOE-SRS, 2005a. FIGURE G-10 Composite picture of the interior of Tank AZ-101, which is considered one of the most complex in the Hanford tank farms.
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From page 173... ...
Neither the Savannah River ancillary equipment is flushed with nonradioactive water Site nor the Hanford Site identifies in-tank debris as a major after use so the remaining waste is expected to contain obstacle to waste retrieval (DOE-RL, 2005; DOE-SRS, amounts of radionuclides that are small relative to what is 2005d)
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From page 174... ...
This has not been demonstrated practically in material believed to be in the pipelines and ancillary equip- Savannah River Site tank farms to date. Experience with ment, and because some of this system is still in use, DOE pipeline plugging and unplugging from Russian Nuclear has accorded characterization and remediation planning a Defense Material production sites has also been published low priority and a formal decision process has not yet been (Florida International University, 2001)
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From page 175... ...
It is worth noting that Savannah River Site staff has bent (albeit very slightly) the coils in Tank 5 to introduce Waste Retrieval from Tanks with Vertical Cooling Coils some of the waste removal equipment.
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From page 176... ...
Outside of primary tank wall Salt waste that leaked from tank and is contained in annulus pan Ventilation duct FIGURE G-14 Salt deposits in the annulus of Tank 16 at the Savannah River Site. SOURCE: Mahoney, 2005.
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From page 177... ...
Hanford Idaho National Laboratory Retrieving waste from Hanford tanks could be easier than The Idaho site has 11 underground tanks containing liquid from Savannah River Site tanks for two reasons. First, sodium-bearing waste and 6 bins of calcined high-level Hanford tanks do not contain cooling coils.
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From page 178... ...
. Work in progress on calcine retrieval in cooperation with AEA Technology includes optimizing the tip of the vacuuming Retrieval of Calcined Waste from Bins nozzle to mobilize compacted calcine deposits as well as Retrieval of calcine waste at the Idaho National Labora- optimizing the control systems to minimize worker fatigue tory is very different from tank waste retrieval.
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From page 179... ...
. Waste retrieval experience for Silo 3 at DOE's Fernald site shows how retrieval of calcine can be challenging.
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From page 180... ...
The site had two tanks used for ground; beta-gamma detectors were employed to establish secondary waste streams during waste processing. The the concentrations of both beta- and gamma-emitting radioretrieved wastes were vitrified in a vitrification facility nuclides remaining on tank surfaces; and a burnishing similar to the one at the Savannah River Site and poured into sampler was deployed within the tank to collect samples of 275 canisters intended for disposal in a repository for high- the waste from the walls, columns, and other vertical and level waste.
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From page 181... ...
Waste removal was typically accom included inspecting the tank walls using both an in-tank plished using spray nozzles and lances to mobilize settled video system and a laser mapping technique to determine if sludge, and the resulting slurry was pumped from the tanks the condition of the walls presented retrieval limitations and (DOE-EM 2001a; 2001b)
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From page 182... ...
; fill material had the advantage of being self-leveling when · Waste conditioning system (Emison et al., 2002) ; and pumped into the tanks, aiding in complete grouting of tanks · Heavy waste retrieval system (ITSR, 2001)
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