Strengthening the safety culture at Hanford's vitrification plant is the key to resolving technical issues concerning the safe operation of the plant, said Peter Winokur, chairman of the Defense Nuclear Facilities Safety Board.
The board held a public hearing Thursday in Kennewick to assess progress on resolving technical issues at the $12.2 billion plant under construction and progress on strengthening the plant's safety culture.
The plant is more than half built and the design is 85 percent complete, but questions remain about whether it will operate safely and efficiently.
On Thursday, Hanford officials said the safety basis for part of the plant would be reconstituted, or partially redone.
The safety basis looks at a broad range of accidents, upsets or other events that could possibly occur as the plant operates and finds ways to prevent them or reduce consequences to protect the safety of staff and the public and allow the plant to go back online.
It effectively serves as a license to operate.
"Clearly, this effort will be made more difficult by the number of unresolved technical issues, the project is addressing that impact safety and the need for controls," said Steven Stokes, the board's lead for the Nuclear Facilities Design and Infrastructure Group. "Reconstituting the safety basis is a significant development and a major undertaking, particularly at this stage of the (vitrification plant) project."
It has the potential to be "very costly and difficult to implement," he said.
The existence of unresolved technical issues further complicates the reconstitution process because many of these issues will require further testing as part of their resolution, which takes time to complete, he said.
"It seems there are surprises all the time," Winokur said. "Until you fix design and set controls in place, you won't have a safety basis."
Design questions remain about whether the plant can keep high-level radioactive waste adequately mixed and whether waste particles will cause erosion and corrosion of metal, wearing out the plant before waste is treated.
The plant is being built to treat up to 56 million gallons of radioactive waste left from the past production of weapons plutonium at Hanford.
Questions also have been raised about the safety culture, particularly whether workers such as engineers and scientists feel free to raise technical issues about the plant's design that could affect its safe operation.
"From the board's perspective, the flawed safety culture at the Waste Treatment Plant is an indicator that the significant organizational weaknesses may be adversely impacting the project's ability to identify, address and resolve critical technical issues, which directly impact the ability of the plant to treat waste safely and efficiently," Winokur said.
Waste must remain adequately mixed to prevent a buildup of particles of plutonium, which could lead to a criticality. Design concerns also have been raised about whether accumulated solids could cause a buildup of flammable hydrogen.
Because parts of the plant will be too radioactively hot for workers to enter once processing begins, fixes then could be difficult or impossible.
The Department of Energy has identified 99 issues with the plant's mixing system for high-level radioactive waste in vessels -- including erosion and corrosion -- according to the defense board. Particles of waste could erode and corrode metal in the plant, causing it to fail before it has treated all the waste.
The erosion issues have been around since 2001 and were addressed again in 2004 and 2008, and four years later they are again an issue, said defense board member Joseph Bader.
The multiple reviews of erosion and corrosion have been done with literature studies rather than laboratory testing, poor understanding of waste chemistry and inadequate margins for wear to account for uncertainty in the project, Stokes said.
As good custodians of the taxpayers' money, resolving erosion and corrosion issues will continue to start with the least invasive methods, said Frank Russo, Bechtel National project director for the vitrification plant.
But it will progress quickly to actual testing, he said.
The studies so far have not just been repetitive, but have looked at new information about issues, such as particle size, as plans for the plant have changed through the years, he said.
Mixing issues may be resolved by treating problematic waste before it arrives at the vitrification plant, said David Huizenga, DOE senior adviser for environmental management.
As a solution to one problem is proposed, it can create problems elsewhere, said Donna Busche, plant contractor manager of environmental and nuclear safety.
In the past, the quality of work by nuclear safety professionals was not acceptable, but it was not questioned, she said.
"You have to have the discussion, you have to have the tough conversations, or we're just not going to solve the problem," Busche said.
There are no plans to place any vessels in question in the plant anytime soon, said William Gay, contractor assistant project director.
"Tremendous challenges remain," said Gary Brunson, DOE director of the vitrification plant engineering division.
However, issues will be resolved and plans made to treat all 56 million gallons of waste, Huizenga predicted.
Work also is moving forward to address safety culture issues at the plant, Russo said.
Many reviews have been done, but the last review by the DOE Office of Health, Safety and Security, or HSS, is the definitive report, Russo said, agreeing with board members. The last review also was the most critical of the safety culture.
HSS has been concerned that Hanford officials have not fully appreciated the current status of the safety culture or what needs to be done to improve it.
Winokur said messages he had seen from Bechtel officials to staff seemed to say that the plant has a very good and robust safety culture, but it could do better, rather than sending a strong message of management support for safety culture improvement.
Part of the problem has been that workers have had to be persistent to raise technical concerns and get those concerns answered in a timely way, officials said.
Successes related to safety culture on the project can be short lived, Russo said. As work advances and different skills or knowledge are needed, the work force has constantly turned over. About 11,000 people have filled 2,800 positions, he said.
HSS plans to do a follow-up review in 2013, but Bechtel would like an effectiveness review before then, Russo said.