The combined punch of a 9.0-magnitude earthquake and the worst tsunami on record heightened public concern about the nuclear consequences of a possible seismic event affecting Los Alamos National Laboratory — and, in particular, the proposed Chemistry and Metallurgy Research Replacement Nuclear Facility.

The authors of the final Supplemental Environmental Impact Statement for the new plutonium facility say that a draft version of their analysis was almost finished on March 11 when the massive earthquake hit the east coast of Japan, triggering the tsunami and leading to the meltdowns of three reactors at the Fukushima Daiichi power plant.

As a result, the National Nuclear Security Administration revised the statement, adding a great deal of additional information about the seismic environment at the laboratory and at the sites under consideration for the proposed multibillion-dollar nuclear facility.

The 2,100-page statement is now in the final stages of public review before federal officials make a formal decision about the location of the facility.

Appendix C includes substantial sections on earthquakes, windstorms, floods and fire. Hazards from the active volcano in the nearby Valles Caldera National Preserve are discussed in the body of the report.

Among the most extreme accident scenarios, the report imagines a once-in-100,000 years earthquake coupled with a "widespread, seismically initiated fire." The earthquake would probably cause glove boxes used to handle nuclear material to topple, igniting fires in the debris and spark explosions in some of the pressurized containers. The vaults containing 6 metric tons of plutonium would hold under the assumptions of the scenario, but 660 pounds of the radioactive metal would be exposed and vulnerable. This highly improbable accident would be so severe that, "the building confinement would fail" and some of the nuclear material would become airborne.

The seismic issue has long been a matter of concern for the nuclear facility. The growing realization of the significance of the Pajarito Fault, along the western boundary of the lab, influenced the decision to abandon the original Chemistry and Metallurgy Research building, which the proposed facility is partly meant to replace.

Escalating concerns about the earthquake hazard also have led to the rapid escalation of costs, from under a billion dollars in 2004 to the current range of $3.7 billion and $5.9 billion. This dramatic change in scale brought the project under additional scrutiny and sparked public pressure for additional analysis under the National Environmental Policy Act.

At a public meeting Tuesday in Los Alamos, Larry Goen, a LANL structural engineer, gave a presentation summarizing the geological features and seismic history of the region.

"The continent is trying to pull apart, which causes an area of weakness in the Earth's crust," he said referring to the Rio Grande Rift that extends into the San Luis Basin in Southern Colorado and south to El Paso. "You could have earthquakes; you could have volcanoes," he said noting the largest swarm of earthquakes have occurred near Socorro.

Also included among the thousands of pages of transcripts, comments, petitions and responses from the security administration, are two papers, written by geologist Bob Gilkeson and Joni Arends, executive director of Concerned Citizens for Nuclear Safety, that detail the shortcomings of the seismic information.

Arends noted there are many gaps in the geological record, including a lack of mapping for two additional faults that appear to be very close to the site next to the plutonium facility on Pajarito Road, where the new facility might be built.

Rick Holmes, the project director for the new facility, was asked why the seismic issue remains unresolved. "It's an issue where there's a lot of information, and when you have a lot of information you can have different technical opinions," he said. "It's an area where the science is never going to stop. Even if they decide to go build the building, during the construction of the building there are going to be questions about the seismic."