More capable Gamma Irradiation Facility opens

Got a satellite, tank, or favorite weapon component you’d like to irradiate?

Early in January workers plan to move 270 pins made of cobalt-60 into a pool of water at the new Gamma Irradiation Facility (GIF) in Area 5, officially welcoming Bldg. 6586 into Sandia’s family of experimental nuclear facilities. The pins will become the gamma source arrays used to subject test objects, such as weapons electronics, to radiation.

The new GIF combines the capabilities of three older radiation facilities—the old GIF in Bldg. 6588, the Low-Intensity Cobalt Array in Area 1, and the Low Dose Rate GIF in Area 3 — into one all-purpose gamma facility. It also adds some experimental capabilities never before available at Sandia.

The facility includes two 10 x 10-ft. test cells, one cavernous 18 x 30-ft. chamber that can accommodate large test objects such as weapon assemblies, military vehicles, or space equipment, and an 18-ft.-deep pool of water where underwater experiments can be conducted.

Lots of concrete
“We are pleased to bring the new Gamma Irradiation Facility on line to support the nuclear weapons complex and our work-for-others customers — principally DoD and the NRC,” says Sandia Nuclear Facilities Manager Ted Schmidt (6430). “This facility incorporates multiple levels of safety and has significantly enhanced capabilities compared to the previous facility. It will satisfy Sandia’s needs for decades.”

The new GIF is safer. Its test cells feature 6-ft.-thick concrete walls, four-pane leaded-glass windows, and serpentine entryways — which together virtually eliminate worker radiation exposures during experiments.

More than 2,600 cubic yards — about 430 truckloads — of concrete was used in constructing
the chambers and pools, says Norm Schwers, Manager of Hot Cells & Gamma Facilities Dept. 6432.

The cobalt source arrays move along underwater tracks beneath the test cells and are automatically raised into and lowered out of the chambers to deliver the desired dose of gamma radiation to test objects placed in the cells. (See “What’s GIF good for?” below right.)

A single test can last seconds to months depending on the test designer’s gamma needs, says GIF facility supervisor Don Berry (6432). Gamma dose rates as low as tens of rads per hour to as high as 300,000 rads per hour can be delivered.

The 10-year design and construction process for the new GIF was completed in May, says Norm. Since then, Dept. 6432 staffers have been preparing for and responding to a series of operational readiness reviews.

The GIF passed a DOE review early this month allowing the radiation sources to be moved into GIF’s pools soon. The building’s official designation as a nuclear facility is expected before the
winter shutdown.

The first radiation tests to verify the chambers’ shielding integrity and characterize their radiation environments are scheduled to begin in January.

Safety and thrift

Creating a high degree of safety and security while minimizing costs were two key considerations during GIF’s construction, adds Norm.

“We looked at all the accidents that could happen and designed against them,” he says. “We considered safety to workers and the public at every possible point.”

As a result, GIF will be certified by DOE as a Category 3 nuclear facility, meaning the threat to
the general public is minimal even if the worst possible consequences of an accident or attack were realized.

“It’s unusually safe for a nuclear facility,” he says.

To bring construction costs down, Sandians Mitch McCrory (6431) and Milt Vernon (6422) visited decommissioned nuclear facilities at other DOE sites, salvaging the leaded-glass window panes used in GIF’s test chambers from Pacific Northwest National Laboratory and hoarding manipulators from the Nevada Test Site, “just in case we ever need to do any hot cell work,” says Norm.

“We estimate we saved well over $1 million in glass and manipulators,” he says.

The total cost of the GIF’s design and construction was approximately $6 million. The facility’s
final design was performed by the Facilities Systems Engineering departments and Mitch McCrory.