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Post by engineerpoet on Jun 6, 2019 23:12:48 GMT 9.5
According to the article, every four years the core container would be removed -- along with the radioactive scale accumulated in its corners and low velocity zones, embrittled steel and corroded welds. Since no one could work in it, it would have to be discarded. Nonsense. Sandblasters, shot-peeners and other tools work perfectly well as robot end effectors. Humans don't have to get inside anything any more to work on it. Heck, the piled-up corium in TMI unit 2 was largely removed by men using hand tools. They stood on a shielded deck and worked through a pool of water. They broke up the corium with long picks and used other tools to put the pieces in buckets to be taken out. Think how much faster and easier it would be when the production volume was there to justify automation!
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Post by Roger Clifton on Jun 7, 2019 8:47:24 GMT 9.5
steel on ships is painted, an important difference You have a point there! In fact other Wikipedia references to the Crossroads Bravo ships say that the residual contamination was only reduced by sandblasting -- as of paint and rust being removed. However the scale that is likely to plate out onto the walls of the molten salt reactor is likely to cling tighter than that. Until someone more knowledgeable corrects me, I believe that the bulk of the loosely connected scale would be incompatible phases within the melt, presumably non-halides like selenides and tellurides. More intimately connected layers would be ionic substitution by exchange of cation charge with iron atoms in the steel surface, such as molybdenum or tin. Even more firmly embedded would be recoil-driven fission products. Since most fission products are beta-active, any scale surface would be blasting x-rays into its vicinity. An efficiency claimed by the article is the experience and skill of the shipbuilder in building with sheet steel. However containers constructed from plate steel have corners and flat junctions with pipework. Where the container deviates from the stream lines, low-velocity zones are created. That's where precipitation occurs, and one would expect scale to accumulate.
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Post by David B. Benson on Jun 7, 2019 18:02:59 GMT 9.5
Roger Clifton, your versimilitude would be enhanced if you first read the Thorcon design description. I posted the link in my just prior comment.
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Post by Roger Clifton on Jun 7, 2019 20:04:32 GMT 9.5
Roger Clifton, your versimilitude would be enhanced if you first read the Thorcon design description. I posted the link in my just prior comment. I'm not predisposed to homework. Perhaps you could save me the bother by quoting the relevant text?
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Post by engineerpoet on Jun 8, 2019 0:03:05 GMT 9.5
Roger Clifton, your versimilitude would be enhanced if you first read the Thorcon design description. I posted the link in my just prior comment. I just read the entire page you linked. It mentions nothing about the details of refurbishment, let alone de-scaling. On the other hand, the primary loop is made of cylindrical sections so it won't have any seriously low-velocity spots except in the plumbing to the freeze valve.
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Post by Roger Clifton on Jun 8, 2019 16:23:09 GMT 9.5
The primary loop is made of cylindrical sections so it won't have any seriously low-velocity spots except in the plumbing to the freeze valve. How smooth should the flow be? Closely following the streamlines of a flow would require surfaces with curvature of the second degree, rather than just cylindrical. Perhaps shapes close to that ideal could be manufactured off site and just mounted in the shipyard. In either location, welding would be necessary. Considering that welds would be immersed for years in a hot conductive fluid, the potential for corrosion is clear. Are there steels whose welding does not create "different metals", that is, regions of different electrochemical potential?
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Post by David B. Benson on Jun 13, 2019 19:03:57 GMT 9.5
JUMP Presents Big Opportunity for Nuclear Scientists, Industry Cory Hatch 2019 Jul 12 INL, Idaho National Laboratory
"Research" on diverting and upgrading some steam during periods of lower electricity generation. The first unit of the Nuscale 12pak, to be located on the INL reservation west of Idaho Falls. From other sources, scheduled start up is in late 2026.
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Post by engineerpoet on Jun 13, 2019 22:21:24 GMT 9.5
Direct link: inl.gov/article/advanced-reactors/The brief mention of "upgrading steam" hints at Cal Abel's scheme to compress LWR output to achieve temperatures upwards of 500°C and store the heat in "solar salt", but it's only the briefest of hints without any meat to chew on.
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Post by huon on Jul 23, 2019 14:04:52 GMT 9.5
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Post by huon on Aug 8, 2019 9:55:51 GMT 9.5
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Post by David B. Benson on Aug 15, 2019 22:51:23 GMT 9.5
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Post by Roger Clifton on Aug 18, 2019 11:54:37 GMT 9.5
EBR 2 design is being resuscitated! US DoE is to build VTR, a sodium-cooled metal-fuelled fast reactor. At 300 MW thermal, VTR is a smaller version of the S-PRISM design, itself based on the successful EBR 2 prototype. Designated as a test facility rather than a power source, VTR may leapfrog the NRC compliance process. However lessons learnt during the construction of the VTR will certainly accelerate the S-PRISM towards market readiness. www.world-nuclear-news.org/Articles/EIS-process-launched-for-US-fast-neutron-reactor
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Post by huon on Aug 25, 2019 11:27:31 GMT 9.5
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Post by engineerpoet on Aug 25, 2019 11:53:38 GMT 9.5
The Idaho National Laboratory is going to host a Nuclear Reactor Innovation Center (NRIC) where companies can test advanced reactors. We should just call it "Son of NRTS". Proudly.
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Post by huon on Aug 26, 2019 14:54:07 GMT 9.5
Good one, EP. (For those, like myself, who have not followed all the name changes at the Idaho site, the NRTS was the Nuclear Reactor Testing Station, from 1949 to 1975.). Given the establishment of the NRIC, as well as the recent developments cited by Roger Clifton and David B. Benson above, we appear to be on a roll. I will post one more article, which gives a good overview of what may be happening with advanced reactors: Why Advanced Nuclear Reactors May Be Here Sooner Than Many Imagine
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Post by David B. Benson on Sept 2, 2019 7:19:16 GMT 9.5
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Post by David B. Benson on Sept 18, 2019 13:40:10 GMT 9.5
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Post by David B. Benson on Sept 27, 2019 10:26:25 GMT 9.5
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Post by David B. Benson on Oct 4, 2019 15:54:59 GMT 9.5
GE Hitachi, Fermi Energia sign small modular reactor MoU 2019 Oct 03 World Nuclear News www.world-nuclear-news.org/Articles/GE-Hitachi,-Fermi-Energia-sign-small-modular-react The Estonian power company is considering 4 different SMR designs. The feasibility study is to be completed in 2020 January.
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Post by David B. Benson on Oct 8, 2019 17:48:05 GMT 9.5
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Post by David B. Benson on Oct 11, 2019 15:32:59 GMT 9.5
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Post by engineerpoet on Oct 11, 2019 21:25:11 GMT 9.5
NuScale needs to be considering 1-packs with remote control rooms, for CHP. And the NRC needs to be considering the abolishment of military-level security teams and per-site resident inspectors for reactors which are walk-away safe and make such expenditures a total waste of money.
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Post by thinkstoomuch on Oct 11, 2019 22:48:55 GMT 9.5
NuScale needs to be considering 1-packs with remote control rooms, for CHP. And the NRC needs to be considering the abolishment of military-level security teams and per-site resident inspectors for reactors which are walk-away safe and make such expenditures a total waste of money.
Engineering and real life come into conflict some times.
Even a 1-pack is a lot of power.
Remote and no inspectors for walk away safe no real problem, IMO, and they kind of go together.
No security, some nut case shows up and figures out how screw things up. We have idiots shutting valves on natural gas supply lines causing lots of damage then legally getting away with it. Remember when tree huggers were pounding nails into trees and why.
Even just closing the output heat line is going to cause some sort of issues. Then the news will point to the failure of the Nuke plant heat is why grandma died of cold. Next to nothing on the cause. Big business and nasty corporations not taking care of people cutting corners for bigger profits. Not logical but it is what gets viewers.
The need for security can be down scaled some, IMO. If we continue having no repercussions for bad actors. Then plan on having some sort plan for site security. At a fraction of the output of full sized plant and even a 24/7 rent a cop or 2 is a serious expense.
Which is why I have serious doubts about the whole SMR idea. It is a great concept but has serious issues with the real world of idiots we live among.
T2M
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Post by engineerpoet on Oct 12, 2019 2:57:29 GMT 9.5
Even a 1-pack is a lot of power. I'm figuring the heat product would be on the order of 120 MW(t) of near-boiling water. Based on my own gas consumption during a fairly representative February, that would serve something over 20,000 dwellings. Figure 15,000 residences at 2.5 occupancy plus some commercial and industrial, so a population of somewhere around 35,000 to 40,000 served per unit. You could set up for smaller population centers but you'd never use all of the waste heat. Not "no security", just minimal security. If you can shut down the unit remotely you can prevent anyone from causing a nuclear accident. Oh, come on! Do you think these things would not have backups? You're going to have to have something to fill in for refueling outages, and possibly supplemental heat during cold snaps. A combination of electric heaters and a furnace of some kind will do. Most of it could be cameras and alarms, with e.g. sworn police officers specially trained and shared with the local department for the in-person response. Most of your security would be stout walls and heavy doors with good locks. Rent-a-cops have a way of falling asleep on the job because there is nothing to do. I'd plan to do without them except for times when there were lots of people around, like refueling. I'd give the sworn cops a few of those shifts too, just to keep them familiar with the site. 4 guys costing $100k/yr each at 1/10 time is only $40,000 a year. Selling 120 MW(t) of hot water at $2/mmBTU is $69,000 a week.If your system is walk-away safe, you can get around a lot of idiocy fairly easily. You will have much more to worry about with idiots throwing chains across your power lines to watch the flash, which they can do anywhere.
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Post by huon on Oct 23, 2019 13:51:51 GMT 9.5
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Post by huon on Oct 25, 2019 7:28:58 GMT 9.5
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Post by huon on Nov 18, 2019 6:29:29 GMT 9.5
Deep Decarbonization of the U.S. Electricity Sector: Is There a Role for Nuclear? Tapia-Ahumada, K.D., J. Reilly, et al. (2019) MIT Joint Program Report Series Researchers at MIT have modeled the interaction of technology--including advanced nuclear--carbon taxes, and CO2 emissions. The results are very encouraging. globalchange.mit.edu/publication/17323Note: In the Summary, which was not part of the study itself, "25 cents per kilowatt hour" should, of course, read "2.5 cents per kilowatt hour".
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Post by engineerpoet on Nov 18, 2019 11:01:42 GMT 9.5
40% "renewable" electricity is certainly too high for a stand-alone grid, and is the wrong metric to begin with; the essential measure is net carbon emissions, which a fossil plant sitting on idle will still create even if it is not generating. Further, the electric tunnel-vision ignores heat, transport and industry which account for much more emissions than the grid.
The choice of the wrong metric and the willful exclusion of the majority of carbon emissions says to me that said study is propaganda.
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Post by huon on Nov 19, 2019 9:54:08 GMT 9.5
EP, I appreciate your stimulating take on the study. But I question your conclusion that the study is propaganda (presumably for renewables). An article from a couple of years ago entitled "The Deep Dispute over 'Deep Decarbonization,' included this preface: "It began as an academic argument over how the world could meet a goal of 90% reductions in carbon dioxide emissions by 2050 known as 'deep decarbonization,' Underneath the academic language is a fight among renewable energy advocates on the one hand and defenders of a role for conventional generating technologies, particularly nuclear, on the other." www.powermag.com/the-deep-dispute-over-deep-decarbonization/My reading is that the authors of the recent study are in the latter group. From the abstract: "From these results, we can conclude that the additional system costs of wind and solar are minimal until they reach about 40% of power supply, but after that level these extra costs rise, making room for other power technologies such as nuclear, which can significantly reduce the carbon price needed to achieve deep decarbonization in the US." globalchange.mit.edu/publication/17323(Amended 5:07 AM, UTC, Nov. 19)
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Post by huon on Feb 7, 2020 14:42:14 GMT 9.5
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