LOS ALAMOS — Los Alamos National Laboratory may soon join the production line for transforming Cold War nuclear weapons into nuclear fuel.

The National Nuclear Security Administration is considering Los Alamos as an alternative for disposing of the plutonium pits that once served as primary cores for some 17,000 now-discarded nuclear weapons.

After the Rocky Flats facility in Colorado discontinued nuclear weapons production in 1992, LANL became the only place in the country where plutonium pits can be made.

After a procedure performed by LANL converts the pits into plutonium oxide, which can be combined with depleted uranium to produce mixed oxide (MOX), a uranium-plutonium fuel suitable for nuclear reactors. The final blending of the uranium-plutonium fuel mixture would be handled at the MOX Fuel Fabrication facility under construction at the Savannah River Site, near Aiken, S.C.

On Thursday, the National Nuclear Security Administration revised the plutonium disposition plan to consider including LANL in the process. In a formal notice, the administration proposed to expand or install the facilities for disassembling pits and converting the plutonium metal into feed stock for nuclear fuel at three locations, including LANL's Plutonium Facility. Two other sites at Savannah River are also considered possible alternatives, with some combination of all three locations most likely.

Political shifts and management issues have forced the National Nuclear Security Administration to revise plans for the program several times since completing its first Environmental Impact Statement in November 1999, and this is the second change in intentions since the last Record of Decision in 2007.

A Government Accountability Office report in March 2010 related some of the problems encountered specifically by the Pit Disassembly and Conversion Facility program, which had been unable to establish a definite cost and schedule projection. It was estimated to cost $3.65 billion to build, but was not expected to be operational until April 2021.

The National Nuclear Security Administration's new notice states that the Tennessee Valley Authority is working with the Department of Energy to evaluate the use of MOX fuel in up to five reactors, but there are no solid commitments from nuclear plants to use the material.

One question hanging over the existing program was whether it was possible to make a certifiable plutonium oxide from dismantled pits that could be used to fabricate the MOX. After LANL answered that question affirmatively, the National Nuclear Security Administration called it "a key component in the U.S. plutonium disposition strategy." A LANL press release added, "LANL is expected to convert at least 2 metric tons of plutonium to oxide by 2018 as part of a larger effort to provide up to 10 metric tons of early feedstock for MOX."

While approving of warhead dismantlement, watchdog groups have generally opposed the conversion plan.

"We're highly in favor of disassembling as many pits as they can and as rapidly as possible, but highly opposed to the mixed oxide," said Jay Coghlan, executive director of NukeWatch New Mexico, noting the heightened concerns related to the MOX fuels at risk during the reactor meltdowns last year at Fukushima in Japan

Most surplus weapons-grade plutonium is in the form of pits, clean metal and oxides, but the rest is contaminated metal, oxides and scraps from the nuclear weapons production process.

The National Nuclear Security Administration has not yet calculated the amount of plutonium that won't be suitable for MOX fuel fabrication. Of the four alternatives under consideration, the agency prefers that any plutonium left over be sent to the Waste Isolation Pilot Program in Carlsbad.

A scoping meeting on the proposals is scheduled for Feb. 2 at the Cities of Gold Hotel in Pojoaque. The deadline for public comments is March 12.