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Post by David B. Benson on Jan 24, 2023 4:23:33 GMT 9.5
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Post by huon on Jan 30, 2023 13:55:28 GMT 9.5
GE Hitachi signs contract for the first commercial N American small modular reactor 29 Jan 2023 Green Car Congress www.greencarcongress.com/2023/01/20230129-geh.htmlThis is great news. In addition, GEH has a number of other prospects for deployment in Canada, the US, and Europe.
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Post by huon on Feb 5, 2023 14:03:49 GMT 9.5
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Post by huon on Feb 15, 2023 13:39:52 GMT 9.5
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Post by cyrilr on Mar 7, 2023 19:07:40 GMT 9.5
I don’t get it. Using nuclear heat to make electricity at 33% efficiency, then using that to run a turbo at 90% efficiency, to make higher grade heat for a supercritical turbine at 45% efficiency. That’s 13% nuclear heat to electric efficiency. How is this a big idea?
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Post by David B. Benson on Mar 8, 2023 2:56:21 GMT 9.5
I don’t get it. Using nuclear heat to make electricity at 33% efficiency, then using that to run a turbo at 90% efficiency, to make higher grade heat for a supercritical turbine at 45% efficiency. That’s 13% nuclear heat to electric efficiency. How is this a big idea? cyrilr, the ‘new technology’ is basically a heat pump to provide the higher enthalpy steam used in the existing steam turbine of a retired coal-burning plant.
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Post by cyrilr on Mar 8, 2023 3:07:58 GMT 9.5
Yes, I guess you can view it that way. It will have a very low COP though as it is a high temperature heat pump. like close to 1 basically? Still makes little sense to me, using turbine power even at 45% efficiency to run a heat pump with low COP to generate more power in the same cycle. If it were something fancy like an acoustic heat pump with a COP of 2 then that would make some sense. Sounds expensive at these power levels as well.
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Post by David B. Benson on Mar 8, 2023 6:49:19 GMT 9.5
Units are degrees Celsius: For this application the heat pump has
COP = (275+273)/(540-275) = 2.068
which seems poor, but the savings is in the reuse of the steam turbine and generator, considerable.
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Post by cyrilr on Mar 8, 2023 14:57:45 GMT 9.5
Units are degrees Celsius: For this application the heat pump has COP = (275+273)/(540-275) = 2.068 which seems poor, but the savings is in the reuse of the steam turbine and generator, considerable. That’s the theoretical COP. You never get that. What is the actual performance?
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Post by David B. Benson on Mar 9, 2023 2:55:14 GMT 9.5
Oops! I used the cooling formula and should have used the heating formula for COP:
COP = (540+273)/(540-275) = 2.956
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Post by cyrilr on Mar 9, 2023 3:20:26 GMT 9.5
Oops! I used the cooling formula and should have used the heating formula for COP: COP = (540+273)/(540-275) = 2.956 Still silly theoretical stuff. Just like Carnot limit. Real systems are way below this. Say you get 2. Then it is 0.45*2*0.45 = 40% efficiency. Thats a huge deal; way better than 33% PWR gets. Forget coal plants, you wanna make this a baseline for greenfield. But if it is closer to 1 then 20% or so. Not good. I suspect it is. Can’t even think about what this looks like. No one makes heat pumps in these tees. What refrigerant is suitable to these temperatures? Maybe you go for acoustic heat pumps using helium.
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Post by David B. Benson on Mar 16, 2023 13:25:02 GMT 9.5
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Post by David B. Benson on Mar 24, 2023 7:34:47 GMT 9.5
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Post by cyrilr on Mar 24, 2023 18:20:13 GMT 9.5
So the author published an article on high cost using a figure that wasnt a cost figure. The entire premise of his article was false. An honest author would retract the article. He just put in a footnote.
Axes to grind. Is there an anti nuke out there who doesnt have them?
I will concede one point. 20 MW is too small.
That is not the key issue however. The key issue is how things are done. Not how big the reactor is. Nukes cost under $300/kWe in the early days. That was FOAK costs as well. The same LWRs as we have today. What has changed is how things are done. Red tape. Massive double standards. ALARA aka good is never good enough so lets spend more. Safety fascism. Pretentious “we are nuclear we are special” attitudes. These are the things that make nuclear expensive. And ironically leads to low quality.
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Post by huon on Apr 1, 2023 12:55:26 GMT 9.5
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Post by cyrilr on Apr 1, 2023 21:13:24 GMT 9.5
BWRX-300 is probably about as simple as an LWR gets. Direct cycle natural convection boiler with dry containment. Being smaller means easier financing, at the cost of higher $/kW. Simplifications such as dry containment and silo construction should mitigate the cost but it will always be more expensive than bigger plants. Nukes have such strong scale economies, even more so today due to endless red tape and bureaucracy (which costs the same for a small reactor thus blowing out $/kW almost proportionally). Project in Poland should have less red tape. The projects in Canada are fairly hopeless in this respect. The Canadians are gleefully taking 50 years just to figure out where to put a repository, with endless stakeholder engagement and other woke nonsense.
GE-H developed the SBWR previously and that went nowhere. Then they developed the ESBWR from that and that went nowhere. Let’s hope three times is a charm.
Kind of funny how they consider it the tenth generation. 8th and 9th generation were not built. I don’t see how paper reactors (even licensed ones) count as a product generation.
I would prefer the Kerena reactor over the BWRX. More output, more efficiency, and no reliance on valves for core cooling (isolation condensers have lots of valves). Plus the pressure pulse transmitters allowpassive switching which GE-H product doesn’t have.
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Post by huon on Apr 17, 2023 13:14:11 GMT 9.5
Radiant receives DoD SBIR award for modeling and simulation of energy resilience and nuclear microreactor integration at Hill [Air Force Base] 10 Apr 2022 Green Car Congress www.greencarcongress.com/2023/04/20230410-radiant.htmlA 1.2MWe microreactor that can be transported and set up quickly.
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Post by David B. Benson on Apr 20, 2023 11:56:59 GMT 9.5
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Post by huon on May 6, 2023 13:17:27 GMT 9.5
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Post by cyrilr on May 6, 2023 19:38:23 GMT 9.5
So the AP300 is a scaled down version of the AP1000, a mostly 30 year old design. The AP1000 is a scaled up version of the AP600, a 50 year old design. The AP600 is a scaled down version of a large PWR from 60 years ago. Which is a scaled up version of a submarine reactor from 70 years ago.
So the AP300 is a scaled down version of a scaled up version of a scaled down version of a reactor that is a scaled up version of a 1954 submarine reactor.
And people are surprised Westinghouse went bankrupt?
What surprises me is this supposed bankrupt company sure is spending a lot of money on new developments. And that people get in bed with them. And that they proudly vlaim they “only” need 4 years to license an already proven design using WWII tech.
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Post by huon on May 20, 2023 14:14:40 GMT 9.5
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Post by cyrilr on May 20, 2023 18:08:06 GMT 9.5
I'm sceptical about such small reactors in general and in particular this technology. Small fast reactors have a very big economic problem in the large startup fissile loading, all at high enrichment too. The first core is technically part of the CAPEX and that really hurts the business case. Similarly many other costs are not very sensitive to scale, things like licensing, security, biological shielding, containment... in fact most things have such a large economy of scale that this makes small reactors really expensive. Nuscale is finding this out at UAMPS, and they have a lower fissile loading and a higher unit rating, as well as sharing many expensive systems and components across multiple reactors. Oklo will be much worse. Might be ok for some niche applications like remote terrestrial powering where the alternative is expensive diesel (brought in at expensive transport costs), but for grid powering this will be a very tough business case.
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Post by cyrilr on Jul 3, 2023 19:16:44 GMT 9.5
world-nuclear-news.org/Articles/Finnish-SMR-targets-district-heating-marketBasically a lower temperature version of nuscale (they need to watch out for IP). Don’t see the point of this; district heating is under 100c so it could be done with a pool type reactor. That’s simpler and cheaper and more accessible. Plus it allows the spent fuel heat to be used productively. District heating does have some issues. High infrastructure cost, paired with low annual utilization, hurts the economics. I live in northern Europe, but my boiler is idle 5 months a year. Shutting down a nuclear reactor 5 months a year is a poor business proposal.
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Post by huon on Jul 17, 2023 9:48:31 GMT 9.5
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Post by David B. Benson on Jul 20, 2023 2:46:28 GMT 9.5
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Post by huon on Jul 28, 2023 12:12:13 GMT 9.5
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Post by huon on Aug 6, 2023 16:25:14 GMT 9.5
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Post by huon on Sept 24, 2023 10:27:26 GMT 9.5
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Post by huon on Oct 4, 2023 13:12:04 GMT 9.5
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Post by huon on Oct 6, 2023 14:02:27 GMT 9.5
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