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Hanford’s plutonium finishing plant

Wed., Nov. 16, 1994, 12:45 p.m.

The Plutonium Finishing Plant was built in 1951 to turn plutonium-rich liquids into solid forms that fuel the guts of nuclear bombs. The secret, heavily-guarded facility was code-named Z Plant.

In 1986, after critical safety audits were leaked to the press, the plant was temporarily shut down. It closed permanently in 1989.

The plant holds 11.2 tons of purified plutonium.


The Plutonium Finishing Plant is an environmental and national security risk. The Z Vaults, four closely-guarded nuclear crypts, contain finished plutonium. Visitors to the vaults must wear lead vests because the bomb materials emit penetrating gamma rays. The vaults will have to be guarded from the potential of a terrorist attack for at least 50 years, when new storage facilities might be available.

The rest of the plant, where the plutonium was fabricated, is a major environmental hazard. It’s the size of a COSTCO store, with unrefined plutonium everywhere. A 1993 Energy Department plan called for processing the scrap, but environmental groups and Hanford watchdogs objected to making more pure plutonium. The plan was shelved.

As Hanford workers started to clean up, they found plutonium scattered throughout: in the attic, in old processing lines, in tunnels, even on the floor. The old “hoods,” shielded and ventilated areas where workers standing behind thick glass handled the plutonium, were full of radioactive sludge.

The plant is a major worker safety hazard. Of the 137 rems of radiation allowed per year for the entire Hanford workforce of thousands, Z Plant workers received a collective 68 rems last year.


Since January, Hanford workers have been scrubbing the tunnels and floors. As they cleaned up, they found even more plutonium than anticipated in an old incinerator building - more than 2 pounds. The cleanup is generating large amounts of plutonium-laced garbage that must be disposed of somewhere.

By June 1995, the plant will no longer dump into the ground any wastes generated by the cleanup. The treated liquids will be sent to a new disposal facility. The radioactive sludge may be stabilized by heating it to evaporate the liquid and turn it into powder.

When the plant is thoroughly cleaned up, cumulative worker exposures will drop from 68 rems to 24 rems.


Security to guard the plutonium costs $12 million a year.

Total budget: $300 million a year. Total workforce: 650.

Final cost to clean up the PFP: Unknown.

Awaiting an environmental impact report.

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