After 20 years, Hanford plutonium plant starts to fall

Shears on the end of an excavator arm tore into Hanford’s Plutonium Finishing Plant on Tuesday afternoon.

The demolition, starting on small metal airlocks attached to the side of the plant, followed 20 years of work to clean out the highly contaminated plant. Nearly two-thirds of the plutonium for the nation’s nuclear weapons program during the Cold War was processed inside.

“This plant is one of the most hazardous buildings at Hanford, and its demolition will be a major watershed in the Hanford cleanup,” said Alex Smith, nuclear waste program manager for the state Department of Ecology, the regulator on the project.

Department of Energy officials have called the plant the largest and most complex plutonium facility in the nationwide DOE complex.

Work to prepare the plant for demolition has proceeded at a deliberate pace, starting with stabilization of plutonium left in the plant in a liquid solution at the end of the Cold War. More recent work has included cleaning out and dismantling highly contaminated equipment.

It led to the start of open-air demolition of the plant Tuesday. An excavator — equipped with shears, a clamshell or a hammer — is expected to perform most of the remaining work, at the same deliberate pace as the plant’s clean out.

“We’ve tried to think of everything we can ahead of time for both engineering and administrative controls to safely bring the facilities down,” said Tom Teynor, DOE project director. “We are going to have constant vigilance as we move through this with sampling and monitoring of the situation.”

Demolition is starting with the Plutonium Reclamation Facility, a 22,000-square-foot annex added to the main plant to recover plutonium from the plant’s waste material as demand for it increased during the Cold War.

By December, DOE contractor CH2M Hill Plateau Remediation Co. is expected to be taking down the small building that contains the Americium Recovery Facility between the Plutonium Reclamation Facility and the Plutonium Finishing Plant’s main section.

The Americium Recovery Facility, the size of a double-car garage, contains the McCluskey Room, where worker Harold McCluskey was injured in an explosion in 1976.

A pause in demolition is planned after that to review what has been learned so far and complete any final cleaning of the main area of the plant, which covers 200,000 square feet and stands three stories tall. Work is continuing there on final tasks, such as removing asbestos and ventilation ducting.

Demolition should be completed about July 2017, ending with an explosion to bring down the plant’s ventilation stack. The planned schedule gives DOE a couple of months to make sure all work is done to have the plant down to slab on grade by a legally binding Tri-Party Agreement deadline of September 2017.

At the plant’s Plutonium Reclamation Facility, work will start at the top of the annex, where one section stands six feet tall, once the airlocks and an outside stairway is down. The interior canyon, where tall skinny tanks holding plutonium hung along the walls, will be the last section to come down.

It will be demolished “in small bites” of about four-foot sections over six weeks, Teynor said.

Demolition materials will be packaged as the plant comes down.

Most of the building debris can be sent to a lined landfill in central Hanford. But some material will have to be packaged and held at Hanford until it can be shipped to the Waste Isolation Pilot Plant in New Mexico, a national repository for material contaminated with plutonium. It is currently closed.

To maintain safety during demolition of the entire plant, real-time monitoring for radiation is planned. Air will be monitored as a precaution not only at the plant, but in other areas of central Hanford, Teynor said.

Layers of fixative have been applied within buildings to contain any contamination on walls and floors, and water will be sprayed during demolition to control dust. A soil berm has been built around the plant to control runoff from the spray.

Soil will be surveyed for radiation at the start and stop of each shift and, if needed, scraped up and disposed of as radioactive waste. The ground and building will be sprayed with fixative again at the end of each day.

Workers on the project, including the heavy equipment operator, will be wearing hooded, anti-contamination suits and respirators that filter air.

This story was originally published November 1, 2016 at 6:57 PM with the headline "After 20 years, Hanford plutonium plant starts to fall."