Radioactive nests of Hanford wasps are science fact

This story was published Friday, August 15th, 2003

By John Stang Herald staff writer

Just think of what of the wasp larvae of H Reactor could grow up to be.

Maybe something out of a Japanese monster flick.

But Bechtel Hanford is tackling the radioactive mud dauber wasps nests of Hanford's H Reactor complex, while trying to entice the insects to use nonradioactive mud for their homes.

Bechtel first discovered this menace June 26.

The company is tearing down the long-abandoned Cold War plutonium-production reactor's contaminated buildings prior to sealing up the main core chamber. Workers found a slightly radioactive mud dauber's nest in a nook in a wall on the south side of the complex, said Bechtel spokesman Todd Nelson.

That was the first time that Hanford had ever encountered a radioactive wasp nest.

Since then, workers have found many slightly contaminated nests in the nooks and crannies of the H Reactor complex next to the Columbia River.

"There's more than dozens," Nelson said.

Female mud dauber wasps pick up mud to create tiny tube-like nests bunched next to each other like tiny pipe organs beneath the eaves of buildings.

At H Reactor, these 12- to 34-inch-long wasps are picking up their mud from the complex's contaminated spent nuclear fuel basin, Nelson said.

Bechtel workers are scraping off the nests and sending them to central Hanford's low-level radioactive waste burial grounds.

Mud dauber wasps are solitary creatures and not aggressive. They don't defend their nests and just stubbornly rebuild them over and over when damaged. These wasps use their stingers mostly to paralyze spiders to stuff one each into a mud tube before implanting an egg on that spider.

"We haven't been provoking them. ... There are no reported stings. No reported buzzing or dive-bombing" of workers, Nelson said.

Bechtel has trapped many wasps so they can be checked for radioactivity. So far, none has shown any signs of contamination, Nelson said.

Also, there have been no reports of wasps growing to disturbing sizes.

However, a wasp apparently picked up some radioactive mud and placed it on a generator trucked to the N Reactor area for maintenance.

Bechtel has marshaled its forces against the spread of the radioactive nests.

After all, in the past, Hanford has faced hordes of radioactive ants, chased nonradioactive escaped alligators in the early 1960s, dealt with a radioactive mouse invading north Richland in 1996, hunted marauding radioactive fruit flies in 1998 and constantly combats tumbling radioactive tumbleweeds.

Because of the wasps, radiological surveys have increased. Efforts to remove radioactive mud have been stepped up.

Borax, which is used as an insecticide, has been added to water collecting in the spent fuel basin, to any damp radioactive soil and to the water sprayed on the site to wet down the dust so it won't blow.

Meanwhile, Bechtel is identifying muddy areas that are free of contamination, hoping to lure the wasps to the nonradioactive mud.

Bechtel expects the proliferation of radioactive wasp nests to soon stop. That's because the adults are expected to soon reach the ends of their several-weeks-long, summertime lives.

Then this becomes a case of whether Bechtel can find the remaining radioactive nests within the huge, multi-storied, multi-roomed, cavernous, nook-filled H Reactor complex that has been untouched by humans for most of the past 38 years since it was shut down.

Unfound radioactive nests will shelter larvae hibernating with their dead spiders through the fall and winter.

When spring comes, the larvae will awaken.

To pupate. To mutate. To eat.

And then break loose.