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PostPosted: Apr 11, 2011 7:32 am 
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A very nice technical summary of the ACR-1000 design features and advantages:

http://www.aecl.ca/Assets/Publications/ ... ummary.pdf


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PostPosted: Apr 11, 2011 9:08 pm 
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Or, if you'd rather pay now (for more D2O) instead of paying later (for enriched fuel), you can build the latest incarnation of the traditional CANDU:

http://www.aecl.ca/Assets/Publications/EC6-TS_Eng.pdf


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PostPosted: May 16, 2011 3:14 am 
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Or you could buy an Indian AHWR, similar design, equal fuel flexibility, cheaper, with passive safety features:

http://www.asiannuclearenergy.com/Business-Opportunities/Plant-Construction/india-plans-exports-of-ahw-reactors-fuelled-by-leu.html


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PostPosted: May 23, 2011 4:27 pm 
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To me the CANDU reactor design has a lot more built in flexibility than most other reactor designs on the world scene today, other than the MSR's of course. One of my favorite Candu variants is the Candu (OCR) reactor. This design is almost as neglected as the MSR is state side.

I don't understand why a light water primary in the ACR-1000 is to be preferred over a low pressure (165 PSI), higher temperature(750F) and thermal eff.(34-38%) profile of the Candu-OCR design. Did the OCR version of the Candu address the positive void coefficient issue of its heavy water brothers? The Wrangler 1 OCR test reactor information seems hard to come by these days. Several old timers I worked with in the past just raved about their experiences at WR-1 when it was operational. When I check the causes for abandonment of this program the only stated reason seems to be budgetary cost cutting back in the 70's. No technical reasons.

I would love to see Dupic fueled Candu's whether, ACR, OCR, or a Pb-Bi cooled primary's. The upgraded Candu's could be a great interim reactor design between the current LWR's and the future MSR's. If fuel down blending is required, a few thorium pins could be added to the Dupic fuel bundles in order to breed U-233 for future use. This would address the current world spent fuel problem with a pathway to the MSR.


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PostPosted: May 23, 2011 4:57 pm 
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yeah, I noticed this, too. I think a salt-cooled CANDU might be better yet. The oil is a fire hazard, and has a mild problem with radiolytic breakdown. Perhaps a salt could be chosen that's chemically compatible with zirconium.


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PostPosted: May 23, 2011 6:01 pm 
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rgvandewalker wrote:
Perhaps a salt could be chosen that's chemically compatible with zirconium.

No chance.


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PostPosted: May 23, 2011 8:45 pm 
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My thinking on Krytox went from Oil-cooled CANDU---Per-fluorocarbons---polymers. Engine lubricants have to be stable, non-corrosive and non-volatile. 12C, 19F and 16O are low neutron absorption isotopes of single isotope elements. Salts are corrosive so a concentrated solution of BeF2 may have problems. Perhaps a copper lining may be a solution. Mg-Al eutectic can be a less chemically active and lower fire risk alternative to sodium. These atoms are non-moderating and suitable for fast reactors too.
If you have a separate coolant and a moderator, it is worthwhile thinking of a non-volatile moderator too. Graphite has Wigner energy problem. BeO is the next choice. How would Be2C behave?


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PostPosted: Jul 04, 2011 8:43 am 
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The product specs on Krytox say it has no breakdown of properties below 10 megarads. That sounds like a lot but inside the reactor that dose is attenuated fairly rapidly (weeks or months). It would be good to know what happens at higher levels of ionising radiation.

Krytox might be great for a dry cask storage application. But inside the reactor?


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PostPosted: Jul 04, 2011 10:12 am 
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A little update on the ACR-1000
Quote:
The federal government has quietly shelved development of a new Canadian nuclear reactor that has already cost taxpayers more than $300 million, and now may never leave the drawing board.
CBC News has learned the government-owned Atomic Energy of Canada Ltd. pulled the plug on the project about six months ago, despite the huge public investment in the technology.
This week, the government sold Atomic Energy's reactor division to a Quebec-based engineering firm that says it, too, has no plans to take the project out of mothballs anytime soon, if ever.


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PostPosted: Jul 04, 2011 3:37 pm 
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What could be the reason for the poor fate of the ACR? If you read the technical summary there are lots of improvements and none of them appear particularly risky. It seems that even the slightest improvements on existing technology don't make it past the valley of death, if they get there in the first place. And that's bad news for something as radical as a liquid fuel reactor.

Take the CANFLEX bundle design. Simple improvement over the existing 37 element bundle, almost exactly the same exept that there are 43 elements and there are two element sizes.

CANFLEX has been in the development stage for over 20 years now. A simple change in the element geometry, 20 years. For pete's sake. What's wrong with all things nuclear?

At this rate of development it would take 200 years and 500 billion to develop a LFTR in north America. The Asians will not just eat our lunch, they'll have finished our dinner before we even decide to get out of bed.


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PostPosted: Jul 04, 2011 4:22 pm 
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Cyril R wrote:
At this rate of development it would take 200 years and 500 billion to develop a LFTR in north America. The Asians will not just eat our lunch, they'll have finished our dinner before we even decide to get out of bed.

hahahaha..... good observation Cyril !

...as for CANFLEX fuel bundles, they can be used in existing CANDU reactors, as well as EC-6: the ACR was not a prerequisite for their use.

With things the way they are now, I seriously doubt that even EC-6's will ever get built: Our union leaders stated flat out that with layoffs approaching 50% (by September), its hard to see how the new owner could proceed with new-builts. It doesn't seem to be their priority.

http://www.spea.ca/


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PostPosted: Jul 05, 2011 5:57 am 
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Indian 700MW PHWR should be close to EC-6 in output and many other characteristics. It is being built in India. But then, it is covered under Cyril's 'Asians'.


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PostPosted: Jul 05, 2011 7:35 am 
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jagdish wrote:
Indian 700MW PHWR should be close to EC-6 in output and many other characteristics. It is being built in India. But then, it is covered under Cyril's 'Asians'.


In case you haven't noticed, I was complimenting you guys. :mrgreen: :lol:


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PostPosted: Jul 05, 2011 9:51 am 
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Quote:
What could be the reason for the poor fate of the ACR? If you read the technical summary there are lots of improvements and none of them appear particularly risky. It seems that even the slightest improvements on existing technology don't make it past the valley of death, if they get there in the first place. And that's bad news for something as radical as a liquid fuel reactor.


Remember though Cyril, solid fueled reactors have engineered safety and everything must work together like a Swiss watch. Any change in the fuel elements can lead to changes elsewhere that are hard to predict. Even a change in the design of spacers for example can lead to some new form of fretting not observed before thus the need for years or even decades of testing of new fuel elements in CANDUs or LWRs. With liquid fuel things are far more forgiving.

David LeBlanc


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