Decommissioning Challenges of MSRE - Eric Abelquist and Tommy Morgan @ ORNL MSRW 2021
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- Опубликовано: 16 сен 2024
- Decommissioning Challenges at the Molten Salt Reactor Experiment Site is presented by Eric Abelquist and Tommy Morgan of UCOR at Oak Ridge National Lab's Molten Salt Reactor Workshop.
Drivers to Take Decommissioning Action
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MSRE is an aging facility-while S&M provides a measure of risk mitigation, ultimately DOE and stakeholders desire more permanent and lasting decommissioning outcome
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Remove/mitigate risk to ongoing ORNL operations/mission; e.g., environmental releases to groundwater
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Fuel drain tanks and associated components are protected from groundwater due to sump pumps that must remove groundwater (FDTs are below the natural water table elevation)
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Physical barriers including concrete cell walls and stainless steel liner must be maintained to ensure integrity of tanks and piping
Uranium Fuel Recovery - MSRE Fuel Salt:
▪U fuel recovery tasks were completed from 2004 to 2008:
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salts were melted and chemically treated,
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molten salts were fluorinated to remove uranium,
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uranium was condensed into cold traps and transferred to chemical (NaF) traps, and
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NaFtraps loaded with the uranium were transferred to an ORNL building for storage
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Fuel salt in two fuel drain tanks and flush salt in flush tank melted for removal using a process known as “pool melt” using a heated probe to melt the salt
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Hydrofluorination process conducted by sparging the melted salt with mixture of hydrogen fluoride, hydrogen and helium to restore chemical balance in the salt; ensuring uranium is in the form of UF4
Decommissioning Challenges
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Aging facility/equipment
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Challenging working environment due to radiological/hazardous conditions requires personal protective equipment (PPE), special tools, portable maintenance shield (PMS)
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Salt waste form... Is there an ultimate disposition pathway/home for waste, like WIPP?
Aging Facility and Equipment
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Potential breach of drain tanks is considered to be highest risk at MSRE
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Would result in F2/HF release, difficult to isolate
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Evaluate need for tank integrity measurements
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Assess extent of tank corrosion on thinning of the tank walls and heat exchanger thimbles
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Relying on ventilation system that is original to the facility for safety significant functions
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Piping and tubing containing holdup infrequently monitored
Presented 2021-10-12 (Oct 12th, 2021) at Oak Ridge National Lab's Molten-Salt Reactor Workshop.
ORNL MSRW 2021 video playlist:
• ORNL MSRW 2021
ORNL MSRW 2021 PDFs:
msrworkshop.or...
ORNL is in the process of releasing their 2021 Molten Salt Reactor Workshop presentations, which ran 2021-10-12 and 2021-10-13. I'll be issuing updates via public Patreon posts. www.patreon.com/thorium
The big surprise was the presence of F2 and HF offgas. I've never seen anyone mention that as a hazard of MSRs. 15:03 "It's not a lot but it's enough to be a significant hazard". How significant? Are we talking about a 50-year buildup that could be safely vented to atmosphere if safety regulations were reasonable? Or are we talking about so much offgas that ventilation isn't enough to mitigate it? Compared with smoke from coal plants that is vented to atmosphere, how big a deal is this really? Also, what causes this offgassing? Is it radioactive? Can it be captured and turned back into a solid?
I appreciate this being put up. While many MSR advocates have spoken to the opportunity for high burn-up rates to minimise the waste problem - it cannot be glossed over either. And for example, while Thorcon blithely talk about shipping reactor cans back to a central site for 'reprocessing' - the devil will surely lie in the details of this.
We need to be honest and well prepared for the obvious questions in this space.
I understand ThorCon will not be shipping any residual radioactive salt within the eight year old used but empty reactor cans which had previously had their fuel salts transferred to the adjacent empty standby can some four years earlier while still within the slightly negatively Helium pressurised sealed confining vault within which both active and empty standby cans and primary heat exchanger were housed. Their four yearly reactive cycle is pragmatically chosen to ensure the useful graphite life is not exceeding. Check out their 5th day training session with their Chinese Chief Nuclear Engineer recently joining after successfully commissioning the T-MSR in the Gobi Desert.
ruclips.net/video/q3v3L5FQSJI/видео.html
@@MrVaticanRag Thanks for the link - I'll check that out.
"Reprocessing" the Can really is a recycling effort (nothing like reprocessing the fuel). It involves opening it up - so a dedicated facility. The graphite needs to be replaced. There is a filter that needs to be replaced. Otherwise, inspections need to be done. But it does require a dedicated facility so the work can be done primarily robotically. As such, it will be a significant investment and one that will not be made until there is a sufficient demand for recycling Cans. We will store the Cans until there is sufficient quantity to be worth building the recycling center.
17:12 "Obviously the facility - it's not really falling down around us, but it certainly was not designed to accommodate workers with today's industrial safety standards. That's kind of the big thing, things are different today than they were when this place was built." My question, though, is whether all the extra standards you need to accommodate are actually worthwhile. It's hard to judge, as Eric & Tommy didn't mention e.g. how much mSv of radiation they might realistically be exposed to if they took only a "1969" level of precautions. Indeed, in 1969 how much would they even worry about the 2-3 kg of UF6 that went to the charcoal bed?
Another issue is the other dangers. If your dosimeter is quiet, it doesn't mean that you won't be hearing the mesothelioma can can with all the pipes covered in asbestos.
What should happen at this reactor right now, is everything in it's entirety should be given to Kirk Sorensen and his FLIBE conglomerate and given free rein under law to use the salt, the stupid carbon additive and use this fuel and salt for a new modular reactor to burn and clean up so it would no longer be putting off fluorine gas and cesium, strontium, and iodine, along with it's 37rad dose salt, let him figure out how to safely use it and decontaminate the fuel salt and give it to him free of charge to use in a new unit so we get off the stinking polluting coal fired units. Then the cost won't be passed to my children's children in tax burden.
Allow me to be the first to apologize as an American for all of that $$$ you have had to spend due to safety concerns, that is truly depressing.
Nice video.