By George Lobsenz
In possible changes that appear aimed at reducing the cost of the multi-billion-dollar program, the National Nuclear Security Administration (NNSA) said Monday it would consider eliminating a major plutonium disposal facility planned for the Energy Department’s Savannah River Site and sending more surplus plutonium to the Waste Isolation Pilot Plant repository in New Mexico.
NNSA, DoE’s semi-autonomous nuclear weapons agency, also said it would look at using up to five of the Tennessee Valley Authority’s commercial power reactors–at the Sequoyah plant near Soddy-Daisy, Tenn., and the Browns Ferry plant near Decatur, Ala.–to burn fuel that is to contain surplus weapons plutonium.
That increases the number of TVA reactors that might use uranium-plutonium, or mixed oxide (MOX), fuel, apparently to replace reactors previously offered for plutonium disposal purposes by Duke Energy Corp., [DUK] which in late 2008 dropped out of a contract with DoE to burn MOX fuel at its two-unit Catawba and McGuire plants.
Most notably, while saying it had made no decisions about changing any elements of its program to dispose of surplus weapons plutonium, NNSA said it would consider scrapping its longstanding plan to build the Pit Disassembly and Conversion Facility (PDCF) at Savannah River in South Carolina.
The PDCF, which had an estimated price tag of at least $2 billion, had been planned by DoE to extract and purify plutonium from nuclear warhead pits in preparation for its conversion into MOX fuel at the Mixed Oxide Fuel Fabrication Facility, a $5 billion project already being built at Savannah River.
The potential elimination of the PDCF comes as NNSA is facing sharply rising costs on new plutonium and uranium facilities it is planning to build at other sites.
Instead of building the PDCF, NNSA said it now would consider a variety of other plutonium disposal strategies, including adding processing capabilities to existing plutonium storage facilities at Savannah River’s K-Area.
The agency also said it would evaluate processing more plutonium through Savannah River’s existing H Canyon, with the plutonium to be added to the millions of gallons of high- level radioactive sludge being vitrified into a glassified waste form at Savannah River’ Defense Waste Processing Facility. Among other issues, DoE said it would look at the implications of increasing plutonium concentrations in canisters of vitrified waste.
Those were just a few of many plutonium processing options outlined by NNSA in a notice of intent issued Monday on possible modifications to a 2007 plan developed by the Bush administration for disposal of surplus weapons plutonium.
DoE has been working for 10 years to carry out a 2000 nonproliferation agreement between the United States and Russia under which each nation agreed to dispose of 34 metric tons of surplus weapons plutonium.
Most of the U.S. plutonium is to be disposed of through conversion to MOX fuel that can be burned in commercial power reactors. After irradiation, the spent fuel was to be permanently buried at a geologic repository, but the Obama administration’s decision to terminate the proposed Yucca Mountain repository in Nevada has raised questions about where the spent fuel will now go.
However, that is only one of the many complexities and uncertainties that NNSA and DoE have been wrestling with in trying to finalize the plutonium disposal program, which has undergone multiple changes since its inception in the 1990s.
In its latest announcement, made in the Federal Register, NNSA said it is only considering modifying its approach for disposing of another 13 metric tons of surplus plutonium; it said plans would not change for the 34 metric tons covered by the U.S.-Russia agreement.
NNSA said it also would look at the implications of adding an unspecified amount of additional surplus U.S. weapons plutonium to the disposal program in the future.
And the agency said it might dispose of small amounts of “gap” plutonium taken from other countries under NNSA’s program to reduce proliferation threats at foreign nuclear facilities.
“DoE…intends to evaluate the potential impacts associated with disposition of additional plutonium to account for the possibility that the United States may declare additional plutonium to be surplus in the future and…small quantities of plutonium (totaling up to 100 kilograms) that the United States may accept from at-risk foreign locations as part of the Global Threat Reduction Initiative,” NNSA said.
Of the 13 metric tons that were the subject of NNSA’s Monday announcement, seven metric tons are in the form of warhead pits and six metric tons are “non-pit” residues that have been long been stored at various DoE facilities around the country, including the Hanford site in Washington, and two of its nuclear weapons labs–Los Alamos National Laboratory in New Mexico and Lawrence Livermore National Laboratory in California.
The PDCF previously had been considered essentially to removing impurities from pit plutonium so it could be fabricated into MOX fuel that could be used by commercial reactors. Warhead pits include other metals that are not compatible with reactor operations.
NNSA gave no explanation for why it was considering abandoning the PDCF, except to say that it now believed needed plutonium processing capabilities could be incorporated into plutonium storage facilities at the K-Area.
Of the 13 additional metric tons of surplus plutonium, the non-pit plutonium is by far more troublesome for NNSA because those residues often contain other radionuclides and toxic materials and thus cannot be easily purified for use in MOX fuel.
In recent years, DoE has changed course several times on what to do with the non-pit plutonium, most recently in 2007 proposing to build a separate vitrification facility for that material at Savannah River’s K-Area.
This time around, NNSA said it would consider processing non-pit plutonium so it could be sent to the Waste Isolation Pilot Plant (WIPP), the geologic repository in New Mexico for plutonium and other transuranic waste. The agency said it would only send plutonium that met WIPP’s waste acceptance criteria, which limit radioactivity levels.
DoE has often sought to send more waste to WIPP, only to retreat in the face of opposition from New Mexico officials. DoE under the Obama administration recently proposed, and then dropped, plans to send more waste from Hanford to WIPP.
NNSA also faces difficulty in using the H Canyon to add more plutonium to the millions of gallons of high-level sludge being vitrified at Savannah River’s Defense Waste Processing Facility, which produces hundreds of canisters of vitrified waste per year that also were destined for Yucca Mountain, but which now have no clear disposal route.
DoE earlier this year quietly moved to increase plutonium concentrations in those canisters above the waste acceptance criteria for Yucca Mountain, but then backed off when its plan was revealed.
NNSA will evaluate all of its plutonium disposal options in a supplemental environmental impact statement (EIS) that also will look at unspecified modifications to the TVA reactors.
In conjunction with TVA, NNSA said it would look at “the impacts of construction of any reactor facility modifications necessary to accommodate MOX fuel operation at five TVA reactors–the three boiling water reactors at Browns Ferry and the two pressurized water reactors at Sequoyah. DOE will evaluate the impacts of operation of these reactors using a core loading with the maximum technically and economically viable number of MOX fuel assemblies.”
DoE also said it was dropping plans to evaluate disposal of surplus plutonium through conversion into a ceramic waste form that would be placed in small cans and then inserted into vitrified waste canisters. It said it would evaluate a similar plan to place containers of vitrified plutonium inside the canisters of vitrified waste.