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Thursday, April 12, 2012

Ecology Ponders Hanford Tank Farm Closure

Jeff Lyon, Tank Systems, Operations, and Closure Project Manager
By Jeff Lyon, Nuclear Waste Program
I have some questions as Ecology’s Tank Systems, Operations, and Closure Project Manager:
  • How long should we wait to close the 149 single-shell tanks (SSTs) at Hanford?
  • What are the risks to humans and the environment if we wait?
  • If we wait for more money or better cleanup technologies (we may never get either), what should we do about the current soil contamination?
  • What will it take to make our decision more certain?
The Draft Tank Closure and Waste Management Environmental Impact Statement (TC & WM EIS) shows that early soil cleanup will help reduce groundwater impacts. About 72 square miles of groundwater under Hanford are contaminated above drinking water standards now. But even if we start today, it will take time to see benefits to groundwater from soil cleanup. But as we wait for action, the conditions worsen.
Part of the Tri-Party Agreement (TPA) is to prioritize Hanford cleanup, and the U.S. Department of Energy (USDOE) schedules that work. One of the TPA milestones is to close all SSTs by 2043. The first of seven waste management areas (WMAs), WMA-C, is scheduled to close by 2019. The schedule requires the remaining six WMAs to be finished in the following 24 years (about one every 4 years). We still have a very long way to go, which makes a good case for finishing WMA-C as soon as we can.
I’m reminded of my high school shop teacher’s motto: You’re not done with your work until you clean up your mess.

All I need to know I learned in shop class

I came onto the tank farms project when USDOE was still performing interim stabilization of SSTs. Interim stabilization meant pumping out all the liquids to stop potential leaks, and that work is mostly done. However, dangerous chemical and radioactive sludge and solids still remain in the tanks.
Hanford tank farm workers use Geiger counters to measure radiation.
Hanford tank farm workers use Geiger counters to measure radiation.
As a result of past interim stabilization efforts, hose-in-hose transfer lines were abandoned in many of the tank farms. They were all flushed with fresh water but unusable. They were past their service life, in the way of retrieval work, and had created tripping hazards.
Then, while retrieving waste from a tank, a gasket in a hose-in-hose transfer line failed, which led to an investigation and enforcement actions. After this, the agencies realized that leaving the lines lying around was not good housekeeping, deciding they must all be removed and properly disposed.
At about the same time, the double-shell tank upgrades were moving forward. When contractors opened old valve boxes, again hoses from transfers performed decades ago remained. Upgrades were more difficult because of the mess left behind.
With those experiences in mind, I don’t want to leave an important step in tank closure half done. We need to finish WMA-C.
We have done a lot of important work, including soil studies and closure planning. But work slowdowns and budget cuts continue to worry me. The TC & WM EIS confirms that the contamination is serious and that the groundwater problems we already face will worsen the longer we wait.
So our advice to USDOE includes my shop teacher’s motto:
Don’t wait! Meet the scheduled deadlines for closing WMA-C. You’re not done until you finish cleaning up!


2 comments:

Jeff said...

At Hanford, USDOE programs produced material for weapons and probably the most complicated waste composition in existence. It was accumulated in the underground storage tanks, and allowed to "age." While the radioactive content declines, the chemical hazards do not go away. A large number of chemical reactions continue in the tanks. The continued production of hydrogen in varying degrees from each tank indicates that chemical reactions continue and have not reached equilibrium. Radiolysis does not account for all the hydrogen generated. Some of it is chemically produced.

The USDOE has minimal data regarding tank waste composition. The WTP process flowsheet is not complete, in part, because of the unknown nature of the waste composition. In spite of this situation, USDOE and their contractor committed to a fast track design build approach to construct and commission WTP. I believe some of the "safety culture" issues noted by DNFSB and USDOE Health, Sefety and Security (HSS) result from contractor staff concern that WTP will not be able to complete its mission.

Of late, USDOE because of DNFSB recommendations, has committed to a costly testing program. Slurry rheological data to date puts the process as designed into an unknown operational space to say nothing of the errosiveness of the slurry on process piping. It is likely that slurry rheology will be but one of many issues not yet known that will plague WTP design, construction, commissioning and operation.

As mentioned in this blog, it appears that WTP as designed will only be able to process one third of the tank waste. I believe it is closer to one fifth. One System is the organization which has been established by USDOE to deal with these issues. Effectively, the unknown nature of the waste and its pre-pre-treatment have been pushed into the future for resolution. Even if current commissioning schedules could be maintained, it would be unlikely that WTP could even come close to an aggregate flowsheet throughput. WTP would be shutdown awaiting the preparation of feed.

Preparation of the other two thirds to four fifths of the tank waste to become WTP acceptable feed would require additional research and development, process flowsheet preparation, design, construction, commissioning, operation, decontamination and decommissioning. While I have not read the EIS, I would be surprised that it accounts for the potential impacts of this additional processing capability.

I believe an entirely new management approach is required. It should start with abandonment of the fast track design build.

Erika Holmes said...

Jeff, we appreciate your very informed comment. As you point out, WTP has a number of technical issues that remain unanswered, leaving WTP’s schedule and some aspects of the treatment process in question. The Department of Ecology will continue to work with USDOE and Bechtel through our Dangerous Waste Permitting process to address these issues. Stay tuned to the ECOconnect blog, Ecology’s Hanford Education & Outreach Network on Facebook, and our quarterly newsletter Tank Waste Treatment News for updates. Thanks for commenting! We hope to hear from you again in the future.