How is hydrogen generated and managed in Hanford's double-shell tanks?

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In summary, there are concerns about the potential for hydrogen gas buildup within a tank, in particular those with a double wall, which contain deadly waste that was previously pumped out of the leaking single-shell tanks. With active ventilation, the tanks should be able to avoid reaching flammable conditions, but the Hanford site needs to be cleaned up.
  • #1
CFDFEAGURU
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Hello all,

I have been reading about the hydrogen problem at the Hanford Vitrification Plant site. Hydrogen and/or other flammable gasses are being generated in the double shell vessels.

Excerpt below is from :

http://www.komonews.com/news/local/Nuclear-board-warns-of-Hanford-tank-explosion-risk-201128721.html

In addition to the leaks, the board noted concerns about the potential for hydrogen gas buildup within a tank, in particular those with a double wall, which contain deadly waste that was previously pumped out of the leaking single-shell tanks.

"All the double-shell tanks contain waste that continuously generates some flammable gas," the board said. "This gas will eventually reach flammable conditions if adequate ventilation is not provided."

END OF EXCERPT

I know that in an operating LWR there is the Zircaloy-Water Reaction (among other reactions). This reaction generates hydrogen. However, in a vessel containing an unknown mixture of nuclear materials, how is the hydrogen being generated and how could one determine to a certain accuracy the amount of hydrogen being produced?

Just because hydrogen is there doesn't mean an explosion is imminent and there are methods to make the atmosphere containing the hydrogen to be non-explosive.

Thanks
Matt
 
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  • #2

Here is a link to an analysis from 2008 indicating 2 weeks to a month to reach a specific level below the LFL (Lower Flammability Level) after loss of ventilation for tanks with active ventilation or Passive HEPA filtration. The reference you provided and similar liinks from a Google search seems to indicate a new analysis from DOE, but I haven't found it.

There are some equations in the report that may help determine the generation chemistry.

http://www.osti.gov/bridge/purl.cover.jsp?purl=/967370-ygCUcv/
 
  • #3
Thanks for the information. The paper is pretty thorough and gives good insight into how quickly a couple of the tanks can reach the lower level.

Thanks
Matt
 
  • #4
I'd expect tanks' atmosphere to be inerted by periodic injections of e.g. nitrogen or argon, making explosions impossible. Is something like this done, and if not, why not?
 
  • #5
nikkkom said:
I'd expect tanks' atmosphere to be inerted by periodic injections of e.g. nitrogen or argon, making explosions impossible. Is something like this done, and if not, why not?

Based on the discussion in the report it appears they use active ventilation on some of the tanks, not inerting. The basic problem is that tanks can leak and are leaking and need to be cleaned up. That would also eliminate issue with hydrogen.
 
  • #6
NUCENG said:
Based on the discussion in the report it appears they use active ventilation on some of the tanks, not inerting. The basic problem is that tanks can leak and are leaking and need to be cleaned up. That would also eliminate issue with hydrogen.

Yes, the site needs cleaned up. It is such a complex process and requires a tremendous engineering effort to bring the Vit plant to operation. Hopefully, in this decade the cleanup will start.
 
  • #7
I had heard that several of the most urgently threatening sites were treated fairly quickly by freezing the entire volume and then excavating the material. However, I've not found any reference to such an action.
What would be a useful overall source record for Hanford cleanup activities? Right now, it seems the process is going nowhere at great expense and it would be nice to know if anything had gotten done.
 
  • #8
CFDFEAGURU said:
Yes, the site needs cleaned up. It is such a complex process and requires a tremendous engineering effort to bring the Vit plant to operation. Hopefully, in this decade the cleanup will start.


It makes me ask why they didn't start this much earlier, like 20 years ago?
 
  • #9
aquitaine said:
It makes me ask why they didn't start this much earlier, like 20 years ago?

The process was started years ago. Fabrication/erection of the plant started 11 years ago.

The link doesn't give the start date of construction but it does give the completion date.

http://www.hanford.gov/page.cfm/WTP

Some more digging yielded these dates. Taken from a Hanford Fact Sheet.

"The WTP will cover 65 acres with four nuclear facilities –
Pretreatment, High-Level Waste Vitrification, Low-Activity Waste
Vitrification and an Analytical Laboratory – as well as operations
and maintenance buildings, utilities and office space. Site
preparation began in October 2001, and the concrete for the first
nuclear facility’s foundation was placed in July 2002. WTP will
reach commissioning in 2019 and full operations in 2022."
 
Last edited:
  • #10
CFDFEAGURU said:
It is such a complex process and requires a tremendous engineering effort to bring the Vit plant to operation. Hopefully, in this decade the cleanup will start.

Or US could simply (gasp) contract French to build a vitrification plant for them.

France has the immence experience in vitrifying nuclear waste. IIRC they went through three evolutionary steps - they had two older reprocessing plants in operation and now they run a third one, with improvements from past experience.
According to their website, in this latest plant, workers exposure is exceptionally low.
 

Related to How is hydrogen generated and managed in Hanford's double-shell tanks?

1. What is the "Hanford - Hydrogen Problem"?

The "Hanford - Hydrogen Problem" refers to the issue of high levels of hydrogen gas being produced and accumulating in the tanks at the Hanford Site, a former nuclear weapons production facility in Washington state. This buildup of hydrogen gas poses a potential safety hazard and could potentially lead to explosions.

2. What is causing the hydrogen gas buildup at Hanford?

The hydrogen gas buildup at Hanford is primarily caused by the radioactive decay of waste materials stored in the tanks. This process produces flammable gases such as hydrogen and creates a buildup in the tanks.

3. What are the potential risks associated with the hydrogen gas buildup at Hanford?

The main risk associated with the hydrogen gas buildup at Hanford is the potential for an explosion. If the gas concentration reaches a certain level, it could react with oxygen and ignite, causing significant damage to the tanks and potentially releasing radioactive material into the environment.

4. How is the "Hanford - Hydrogen Problem" being addressed?

The Hanford site is implementing various strategies to address the hydrogen gas buildup, including installing ventilation systems to remove the gas from the tanks and adding chemicals to reduce the gas production. Additionally, efforts are being made to empty and transfer the waste to newer, safer storage facilities.

5. What are the long-term plans for the hydrogen gas buildup at Hanford?

The long-term plan for addressing the hydrogen gas buildup at Hanford is to empty and transfer all of the waste from the older, single-shell tanks to newer, double-shell tanks. The ultimate goal is to safely dispose of the waste and eliminate the potential for hydrogen gas buildup in the future.

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