Affordable Cleanup? Opportunities for Cost Reduction in the Decontamination and Decommissioning of the Nation's Uranium Enrichment Facilities (1996) / Chapter Skim
Currently Skimming:
7 DISPOSITION OF THE DUF6
7 DISPOSITION OF THE DUF6
Pages 157-182
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 157... ...
DUF6 INVENTORY The total DUF6 material inventory is more than 500,000 metric tons (357,000 metric tons of uranium)
|
From page 158... ...
Its high density could also make uranium attractive for use in flywheels. 2 A recent report from the Defense Nuclear Facilities Safety Board notes that "demand for depleted uranium has become quite small compared to quantities available" (DNFSB, 1995~.
|
From page 159... ...
Disposition of the DUF6 159 FIGURE 7-1 DUF6 cylinder storage yards at Paducah. (Yards encompass about 40 acres and contain about 20,000 cylinders or 40 percent of total DOE inventory.)
|
From page 160... ...
, manufacture of uranium oxide breeder reactor blanket fuel or mixed uranium-plutonium oxide fuel for power reactors, and dilution of very high-assay, weapons-grade uranium to an assay suitable for nuclear power plant fuel. Shielding Applications Special casks are being manufactured for the transfer and dry storage of spent nuclear fuel.
|
From page 161... ...
AVLIS requires uranium metal feed, so the DUF6 must be converted to metal; this conversion is an expensive process. A further disadvantage of using DUF6 feed for AVLIS is 3 Personal communication from John Hewes, Allied Signal, Research and Technology, to James Zucchetto, National Research Council, December 1, 1994.
|
From page 162... ...
Thus, the use of DUF6 as 5 The committee evaluated the tradeoffs in using DUF6 as a source of uranium metal for AVLIS using very approximate process and cost estimates as follows: Cost of DUF6 feed Cost of natural UFO Conversion costs - UF6 to U metal - U metal to U3O Material handling, storage cost of SWUs - AVLIS - diffusion $0/kg $30/kg U $10/kg U $0.5/kg U $2olft2 $20/kg U $100/kg U The USEC has not disclosed any projected AVLIS costs. A low cost estimate by the committee of $20/kgU SWU was used to give an optimistic (high)
|
From page 163... ...
A surveillance and maintenance program could be continued; the material would later be converted to a more stable form for very long term storage. 7 In response to a DOE Federal Register request for management options for the DUF6, it was noted that the deployment of 100 breeder reactors would use only about 1 percent of the DUF6 inventory per year (Zoller et al., 1995~.
|
From page 164... ...
A recent report from the Defense Nuclear Facilities Safety Board also notes such inadequacies in cylinder storage (DNFSB, 1995)
|
From page 166... ...
Prolonged worker exposure in the cylinder yards presents a small potential hazard. Information provided to the committee indicates that, following the evaluation of the radiation dose received by cylinder inspectors at the Oak Ridge site, an average of 25 hours per week spent in the cylinder yards was recommended in 1992 to control maximum yearly exposure.9 This recommendation is based on an average exposure of 1.5 mrem/hour.
|
From page 167... ...
No federal regulation requires conversion of the DUF6 to a more stable form. On the other hand, the Nuclear Regulatory Commission has proposed limiting the quantity of DUF6 in storage at the proposed commercial gas centrifuge plant in Louisiana to 80,000 metric tons of UFO or 15 years of production, whichever comes first (Zeitoun, 19941.
|
From page 168... ...
. Continued Surveillance and Maintenance: Requirements and Costs The DOE review of cylinder storage recommended improved storage practices, and a recent report from the Defense Nuclear Facilities Safety Board also recommended changes (DOE, 1992; DNFSB~, 1995)
|
From page 169... ...
Excess capacity currently exists in the U.S UFO to uranium oxides. although the volumes of In France, Cogema has successfully operated a conversion plant since 1984, producing 7,000 metric tons of U3O~ and 4,300 metric tons of 70 percent aqueous HE annually.
|
From page 170... ...
. The plant size was chosen to provide the same nominal operating capacity as the Cogema plant in France; that is, to be capable of converting 35,000 metric tons
|
From page 171... ...
The plant size required for conversion of about 360,000 metric tons of uranium over a period of 20 years is larger than the MMES study design by a factor of 2.55. The capital investment would be larger, but not in direct proportion to plant capacity.
|
From page 172... ...
This is in the middle of the usual range for industrial plant maintenance costs. i3 Personal communication from Robert Pratt, Allied Signal to the Technology Panel of the Committee on Decontamination and Decommissioning of Uranium Enrichment Facilities, Metropolis, Illinois, October 19, 1994.
|
From page 173... ...
and compares this to data from the original MMES study based on a small plant for Oak Ridge only. Transportation to a western site and long-term burial costs add significantly to the total costs, from $283 to $432 million (depending on the unit burial cost)
|
From page 174... ...
5 % of feed and cylinder handing; conversion and waste handling facility; and support facility 249.0 D&D 39 16 5596.5 Total conversion in 1991 dollars 3101,139.0 Total indexed to 1995 dollarsb 3161,161.0 Transportation to long-term storage Long-term storages For storage cost of $30/ft3 For storage cost of $58.70/ft3 Cost over plant life in 1995 dollars For storage cost of $30/ft3 For storage cost of $58.70/ft3 127 156.0 305.0 1,444.0 1,593.0 a MTU is metric tons of uranium. b Chemical Engineering plant cost indices; 1991-361.3; 1995-368.3; index factor 368.3/361.3 (McGraw Hill, New York)
|
From page 175... ...
The conversion plants discussed above are small by conventional chemical plant standards. Although in the preceding analysis the plant size was scaled to handle the DOE legacy material, processing costs could be reduced by sizing a single plant to handle all the DUF6, regardless of origin, that is, to convert both DOE legacy material and DUF6 owned by the USEC.
|
From page 176... ...
In contrast, a 5-year operation would generate about 8 percent of North American HF requirements each year with resulting repercussions on the market. An appropriate choice of plant size and schedule would reduce conversion costs.
|
From page 177... ...
However, process modifications might result in somewhat lower conversion costs. Because the stringent criteria controlling ceramic reactivity and physical properties of nuclear fuels are not appropriate for a material destined for waste storage, some changes from the usual fuel technology might be acceptable.
|
From page 178... ...
3. The cost of converting DUF6 to UPON should be minimized by an appropriate choice of plant size, plant location, and schedule for conversion operations.
|
From page 179... ...
DNFSB (Defense Nuclear Facilities Safety Board)
|
From page 180... ...
Presented to the Committee on Decontamination and Decommissioning of Uranium Enrichment Facilities, National Academy of Sciences, Washington, D.C., July 10, 1995.
|
From page 181... ...
Presented to the Committee on Decontamination and Decommissioning of the Uranium Enrichment Facilities, The Beckman Center, Irvine, California, December 12, 1994. USEC (United States Enrichment Corporation.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.