Seattle Times Trinity Web: Nuclear leftovers

COLD WAR HANGOVER, PLUTONIUM HEADACHE

IMAGE: A gloved hand reaches into the cluttered, steaming chamber.
At the Plutonium Finishing Plant at Hanford, wastes are heated to 1,000 degrees Celsius in this chamber to remove moisture, eliminate explosive gases and reduce volume.

WHEN THE COLD WAR ENDED, America's nuclear-warhead-production system shut down so rapidly that weapons-grade isotopes were left stranded, so to speak, on the assembly line.
   The United States had produced 100 finished tons of plutonium from which to fashion warheads. Fifty-three of those tons were made at Hanford. Another 26 tons were in intermediate steps before weapons fabrication.
   Dealing with these leftovers has become one of the top cleanup priorities at Hanford Site in Eastern Washington. The Seattle Times recently got a rare peek at the plutonium-storage vaults there, encased in a windowless concrete building and locked behind 5,000-pound doors.
   Hanford's Plutonium Finishing Plant is the factory where liquid-nitrate solutions of plutonium from the nuclear reservation's Purex Plant were turned into palm-sized silvery "buttons" that could be machined into warheads.
   Each button cost $2.8 million to produce, and the laborious process of going from liquid to solid metal took about two weeks. Technicians used soft gold drills to probe button interiors, testing for quality.
   "This is probably the most secure place in all of Hanford," manager Rick Redekopp said as we laboriously "suited up" to enter the finishing plant. The plutonium was manufactured on a conveyer belt shielded by metal and glass and accessed by "glove boxes," or windows fitted with shielded gloves through which workers could purify the metal.

   Abrupt shutdown left a residue of plutonium and chemicals along the gritty conveyer line. Now workers are carefully scraping off the gunk, heating it in small ovens to 1,000 degrees Celsius to burn off potentially explosive gases and reduce its volume, and then packing it in lead-lined cans, one inside another inside another. They look like large food cans.
   If all this waste were stacked together, the concentrated radioactivity could spark a chain reaction and a fire or meltdown. Accordingly, the cans are taken to the plutonium storage vault and stored inside lockers, each can on its own bracket to keep it from coming into contact with the others.
   They will remain at Hanford for the foreseeable future. While the plutonium will persist for tens of thousands of years, no decision has been made about its long-term fate. It could be turned into glass and buried, or refabricated into reactor fuel.
   The storage vault is monitored by the International Atomic Energy Agency, the same United Nations body that polices Iraq. "We can't move it without them knowing about it," Redekopp said.
   Caution about radiation soars as one nears the plutonium vault. One passes several checkpoints, is escorted by an armed guard, and is offered a lead vest plus two electronic radiation dosimeters, another called a "pencil," and three radiation badges.
   Terrorists could not use the unrefined plutonium powder salvaged from the assembly line to make a bomb. But it would represent an enormous shortcut for a country trying to fabricate bomb-quality material. It could also be used to salt a conventional explosive that would spew radioactive dust across a city.
   Plutonium was not the only radioactive material stranded when weapons production ended. Next to the abandoned K reactors (new reactor sites were designated with letters of the alphabet), which were used to make plutonium from uranium fuel rods, water storage basins hold 300 tons of weapons-grade fuel and 1,800 tons of ordinary reactor fuel.
   New doors to prevent the 40-year-old pools from breaching in an earthquake have been installed. Meanwhile, plans are being completed to move this mess to dry storage, where it is less likely to contaminate the environment.

Other related articles