Energy Secretary Steven Chu continued to work on Hanford vitrification plant issues through Friday evening in Richland.
He arrived Wednesday with a team of independent scientists and engineers who he picked to take a fresh look at Hanford Waste Treatment Plant issues, specifically focusing on the plant's black cells.
Washington Gov. Chris Gregoire's staff had tried to arrange a meeting between the governor and Chu while the energy secretary was in the Tri-Cities, but his schedule was too tight.
The team was working long days, through meals and into the night, and has had extensive discussions and briefings with contractors and federal staff at meetings at Pacific Northwest National Laboratory in Richland.
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They officials also stayed at the lab, which has accommodations on campus for visitors.
The group is working closely with Dave Huizenga, the senior advisor for DOE's Office of Environmental Management, and Scott Samuelson, the DOE Hanford Office of River Protection manager.
The vitrification plant is being built to treat up to 56 million gallons of radioactive and hazardous chemical waste left from the past production of plutonium for the nation's nuclear weapons program. It will turn waste into a stable glass form for disposal.
The plant is planned to have 18 black cells -- enclosed concrete rooms with tanks and piping that are designed to have no worker access during the 40 years the plant operates because of high levels of radioactivity.
To eliminate the need for hands-on maintenance, pulse jet mixers without moving parts have been designed for tanks of high-level radioactive waste in the black cells. The mixers suck waste up and then shoot it back out to keep the waste well mixed and prevent particles from settling, which could cause problems that include a criticality.
Chu and his team are looking at possible failures in the black cells. They're considering what the response would be and what can be done now to prevent or prepare for potential problems, said Stacy Charboneau, deputy manager for the DOE Hanford Office of River Protection, at the Hanford Advisory Board meeting.
Chu did not stop by that meeting Thursday and Friday in Kennewick, nor was he reported at any other events in the Tri-Cities this week. DOE staff had said before he arrived that he planned to focus exclusively on work with the team of experts looking at vitrification plant issues.
The team, whose members were announced in early August, began work before the visit to the Tri-Cities. They're expected to continue work on the issue after leaving town.
An overall review is expected to be made public after Chu and the team finish their work, according to DOE.
Two members of the team, Richard Meserve, former chairman of the Nuclear Regulatory Commission, and Arun Majumdar, the first director of the Advanced Research Projects Agency-Energy, have not been able to participate because of personal commitments.
Gregoire still plans to connect with Chu even though a face-to-face meeting could not be arranged this week, said Karina Shagren, a spokeswoman for the governor.
They're expected to discuss court-ordered deadlines for the vitrification plant that DOE has indicated may be missed, including a deadline to have the plant in full operations at the end of 2022.
The deadlines are part of a consent decree signed in October 2010 to resolve a lawsuit filed by the state against DOE.
Gregoire and state Attorney General Rob McKenna sent Chu a letter about the consent decree in late August, asking for a response by Sept. 26.
Gregoire also said in an earlier statement that Chu indicated he would discuss the results of his review of the vitrification plant black cells with her.