APS questions new uranium enrichment technology

As GE Hitachi (GEH) Nuclear Energy awaits US Nuclear Regulatory Commission licensing of a first-of-a-kind commercial uranium enrichment technology, the American Physical Society (APS) is awaiting an NRC decision on a year-and-a-half-old petition to require the commission to explicitly weigh the proliferation risk raised by the new laser isotope-separation process. The commission is expected to rule on the license application this month, with a decision on the APS petition to follow in October.

Submitted in November 2010, the petition argues that the separation of isotopes by laser excitation (SILEX) technology that GEH hopes to use in manufacturing nuclear fuel for commercial reactors could heighten the global risk of a nation clandestinely acquiring nuclear weapons capability. It reasons that the greater efficiency of the SILEX process makes it likely that enrichment facilities will be smaller and therefore more easily concealed than today’s gas-centrifuge enrichment facilities. For nuclear fuel, the fissionable uranium-235 isotope, which makes up about 0.7% of naturally occurring U, must be enriched to 3% or 4%. For nuclear weapons, the enrichment level must be 90% or more ²³⁵U.

Worth the risks?

Discussing the issue at a Capitol Hill briefing, Francis Slakey, APS associate director of public affairs, said that SILEX technology is up to 16 times more efficient than centrifuges at separating ²³⁵U from the far more plentiful ²³⁸U. But even if SILEX captured the entire US market for nuclear fuel, it would at most lower a US consumer’s electricity bills by $1.85 per month, he said.

Although GEH commissioned an external proliferation review of the technology, it was just seven pages long, with three of those pages comprising biographies of the reviewers, said James Acton of the Carnegie Endowment for International Peace. GEH hasn’t made the report public because it contains proprietary information, said Ruth Ravitz Smith, who heads government relations for the company. But she said the independent review concluded that a commercial SILEX facility will pose no greater proliferation risk than does a gas-centrifuge enrichment plant. The company’s assessment also concluded that the technology is well beyond the technical capabilities of nations that are aspiring to build nuclear weapons.

That didn’t satisfy Acton, who recounted how Abdul Qadeer Khan had replicated the centrifuge technology from the Netherlands, and how that led to Pakistan’s acquiring nuclear weapons capability. Khan’s plant of 3000 centrifuges was less than 1/100 the size of today’s commercial enrichment plants.

A long-term problem

According to Acton, a proliferation review should have to consider the possibility that a nation could build a much smaller laser isotope-separation facility than the commercial-scale 600 000-square-foot facility GEH intends to build in Wilmington, North Carolina. Although the company insists that everyone with knowledge of the process is properly cleared, Acton noted that “the challenge is to stop a leakage over the decades” of plant operation. He added that even if information about the technology doesn’t leak out, other states are likely to attempt to replicate it, by the GEH process or some other way. Another unknown, said Acton, is how easily the SILEX process could produce highly enriched weapons-grade uranium. Smith said the Wilmington plant would have controls in place to ensure that material is not enriched to more than 8% ²³⁵U.

According to Slakey, the APS petition drew 2386 responses in favor and one, from the Nuclear Energy Institute, opposed. He said the NRC can draw from other agencies, notably the Department of Energy, for the expertise necessary to assess a proliferation review.

The carbon dioxide lasers used in the SILEX process are easily acquired, said Slakey. More difficult to obtain are the high-vacuum components, which, he said, only “half a dozen” manufacturers in the world can produce.

Smith said the company has taken no position with regard to the APS petition. But she insisted that the development and deployment of SILEX has significant barriers to proliferation. Said Smith, “Every step of the way is being coordinated with an interagency group.”