Pacific Northwest National Laboratory could continue to use some buildings in Hanford's 300 Area for up to 20 years, according to options considered in a Department of Energy draft environmental assessment.

No decision has been made, but the document lays out a scenario that calls for building in phases a new government-owned Physical Sciences Facility for research using radiological materials.

The initial building, to be completed by 2010, would be 240,000 square feet and could be expanded to 332,000 square feet to house about 480 scientific and support staff.

It's one of four new facilities planned for the national laboratory in Richland to replace about 560,000 square feet of space now used by workers in the southern end of Hanford.

DOE planned to have the 300 Area buildings leveled when it awarded the contract to Washington Closure Hanford to clean up the nuclear reservation along the Columbia River. The area is contaminated with radioactive and hazardous chemical waste from the past production of plutonium for the nation's nuclear weapons program.

But as it became evident that a planned 325,000-square-foot building could not be built with desired features for the budgeted $210 million, DOE began considering keeping some 300 Area buildings.

At the smaller initial size, the building would house ultra-trace, radiation detection and materials science and technology research programs. It would be built near the Battelle campus just north of Horn Rapids Road outside Richland city limits.

The ultra-trace module would include specialized labs and instrumentation for developing and testing methods for treaty verification related to nuclear and chemical weapons. The radiation detection module would include a paved track outside the building for testing the detection of radiological materials in vehicles and containers.

The materials science and technology module would include laboratories for processing radioactive material samples to study their performance in high-radiation and high-temperature conditions. Work would help evaluate the aging of materials in nuclear power plants and the development of radiation-resistant building materials for reactors.

Later construction phases would include space for shielded operations to protect workers doing research with radiological materials, plus chemistry and processing, subsurface science and certification and dosimetry programs.

"These capabilities could remain in existing 300 Area facilities for a span of 20 years," the environmental assessment said. "They would be relocated if DOE decides to construct additional (Physical Sciences Facility) modules in the future."

There is not a budget or schedule for the additional construction.

DOE has discussed the possibility of retaining four buildings in the 300 Area, including the Radiochemical Processing Laboratory; the Radiological Calibrations Laboratory; a shop building and the 331 Building, a 1970s laboratory and office building with an addition added 10 years ago.

The Radiological Processing Laboratory is a Nuclear Hazard Category 2 facility. But the shielded operations module that eventually could replace it under the phased building approach would be a Category 3 facility.

Projects relocated from the 300 Area are expected to require a smaller total inventory of radioactive materials that would be covered under Category 3, according to the environmental assessment.

The shielded operations module that eventually could replace the Radiological Processing Laboratory could include space for programs related to fusion energy, tritium production, instrumentation for use in high-radiation environments, the production of medical isotopes and the analysis of spent nuclear fuel.

The chemistry and processing module would have hoods, glove boxes and shielded facilities to support fundamental research in radionuclide chemistry as well as other projects.

The subsurface science module would be used to support fundamental research on the mobility and degradation of compounds, and the certification and dosimetry module would provide capabilities to certify the performance of radiation detection instruments.

A decision on whether to use a phased construction plan could be made in early 2007.

DOE will accept comments on the environmental assessment until Dec. 13 at psfea@pnso.science.doe.gov.

The environmental assessment is posted at http://pnso.oro.doe.gov/Default.aspx?tabid=97.