Off the Siberian coast, not far from Alaska, a Russian ship has been docked at port for four years. The Akademik Lomonosov, the world’s first floating nuclear power plant, sends energy to around 200,000 people on land using next-wave nuclear technology: small modular reactors.
This technology is also being used below sea level. Dozens of US submarines lurking in the depths of the world’s oceans are propelled by SMRs, as the compact reactors are known.
SMRs — which are smaller and less costly to build than traditional, large-scale reactors — are fast becoming the next great hope for a nuclear renaissance as the world scrambles to cut fossil fuels. And the US, Russia and China are battling for dominance to build and sell them.
The Biden administration and American companies are plowing billions of dollars into SMRs in a bid for business and global influence. China is leading in nuclear technology and construction, and Russia is making almost all the world’s SMR fuel. The US is playing catch-up on both.
The Akademik Lomonosov was supposed to cost the equivalent of $232M, but ended up somewhere north of $700M all for a net electrical output of 64MWe. In that respect, it follows a familiar path for nuclear projects.
On a cost/kW basis, it’s about three times the cost of wind installations. ($3625/kW vs $1300/kW)
The last co-gen plant I worked on had an output of 353MWe and cost about $450M, which was about $50M under budget.
This misses one of the key points about smr’s. They’re supposed to be made in a factory. That ship is one unit and expensive as hell. If you make 100 or more of the same smr, you can amortize the tooling cost over many units. This also allows for configurable size stations. Right now, nuclear stations are one and done, custom jobs.
People keep saying this, but it’s not accurate.
An EPR is an EPR, the same with the AP1000. There are only very minor differences between installs, usually things that will help ease of construction or reliability on future builds. Both are GEN III+ designs, greatly simplified compared to previous generations, with fewer pump, valves and pipe-runs. They also shortened pipe runs where possible. They also have large, factory-built assemblies that are shipped to site, ready to “bolt” in, which should have reduced site construction time.
Where major changes do happen, it’s with the balance of plant infrastructure, which is site dependent. Location of access roads, where the switchyard is installed, where cooling water is accessed , etc will never be the same between sites. Nor will the geotech information. So a lot of mainly civil and structural design and fabrication will always be site specific.
The KLT-40S reactor is a variant of the KLT-40 reactors developed for and installed in the Taymyr icebreakers back in the late 1980s. It should have been cheap, as it’s a known quantity with a long track record.
Yes, Soviet/Russian technology, the posterchild for prudence and carefulness.
to be fair, it’s trivial to design a safe reactor, the RBMK just wasn’t a good design.
There is a paper out there on the presumed design of russian naval reactors if you want to have a read yourself. It’s decently informed.
I’ve been following the situation in Canada. Afaik the closest we are to getting SMRs is a plan to supplement power production at the Darlington, Ontario CANDU plant using SMRs of the GE Hitachi design. The utility is seeking regulatory approval on the first of 4, but they haven’t broken ground yet to the best of my knowledge. Each would put out up to 300 Mw, so I guess the completed project would add 1.2 Gw to the grid.
Ontario gets around half its power from nuclear, and the current provincial government is gung-ho on building more capacity. While I am not opposed to the idea (they would need to build more anyway just to maintain that ratio in coming decades), the fact that it comes at the heels of them cancelling nearly every renewable energy project at the beginning of their term adds a sour note. These included those that were actually under construction, and tax money had to foot the bill on broken contracts. It was flabbergasting. I am cautiously optimistic about SMRs but they are still vapourware for the most part at this time.
It’s a known tactic of the fossil fuel industry (and the politicians they own) to push SMRs as a delay tactic, so they can continue to make money from coal and gas for a bit longer. And conservative parties get to play culture war over it, which we know they love to do.
If something real comes out of it then great, but you can’t plan an energy transition based on a technology that isn’t proven yet.
Oh man, that is just depressing. I mean I wouldn’t put it past them. It’s like this whole business with carbon capture.
A couple of years ago, I was driving around the Permian Basin near Midland, Texas. I asked a local about all these gas flares you’d see. He said it’s waste natural gas. They’re drilling for oil, you see, so they just burn it off. When I looked incredulous, he added that it’s better than simply venting it. Methane is a potent greenhouse gas! Well sure, but…
Let’s just say it would take a lot to convince me at this point that the future is carbon capture.
That’s absolutely what’s going on here. the whole “nuclear renaissance” is nothing but a smoke screen.
Yeah unless it’s we all suddenly rush to build them and all the renewable options for padding the grid then, yeah. It’s just a ruse to make it look like we are doing anything at all to make people feel better about flying private jets for a day trip to their favorite fishing pond. (Something I know a millionaire does personally)
It’s like this whole business with carbon capture.
Yep, it’s very similar to the CCS push from the 2000s. And you saw the Democratic party pushing it too, despite it fast becoming obvious that it’s not viable.
That just shows that nuclear is nothing but a smokescreen for perpetuating fossil fuels. First they cancel the renewable projects because they have all those fancy new nukes now. Then the nukes never pan out (as they do). Oh shucks, guess we have to keep using coal.
That’s not quite accurate. All the coal power plants in Ontario were shut down about 5-ish years before. Then they had planned more renewable capacity. Then a new leader of the province came in to power (the brother of a famous crackhead mayor), spent money to cancel the projects not with anything to do with nuclear but out of spite of the previous Liberal government.
Second, you look to Germany whose nuclear power plants were shut down which forced them to reopen coal power plants. Yes renewables are coming in hot and it’s the future, but don’t get the timeline twisted just to shift blame on nuclear, especially in my native Ontario.
Indeed yes, the idea of using these technologies to distract from other green energies is a valid concern, but I’ll say that until we have fusion (that is always 20 years away from reality) it takes all kinds of green energy sources to transition.
When they say small, how small are we talking? The size of a sedan? A school bus?
One of the less widely discussed issues with nuclear is that the bigger plants are all somewhat unique in their engineering particulars, which makes it more costly to maintain them. SMRs can be more readily standardised, which is expected to improve their economics as well as their cost to maintain.
If I’m not mistaken SMRs also handle power demand shifts better and don’t have to just do a base load. Something very useful with the growth of renewables and how they are not always supplying power.
I doubt it. Unless they have power storage of some kind, like SSR designs where they use a thermal battery of some kind.
The fundamental issue with nuclear power is that it produces a fixed output (which falls over time) which cannot be managed. Aside from just deleting what would otherwise be power (which is where the power storage comes into play)
It’s not impossible though, but then again it’s not impossible for any nuclear plant to store energy.
The small reactors on submarines can maneuver very quickly without causing fuel damage. Less power per core = less heat generation. Large reactors are limited by flux rate because they can have such high localized heating during maneuvering which has the potential to damage fuel. In that sense, SMRs could raise and lower power to meet demand or even operate on full power/standby basis like what gas plants offer during peak load.
I can’t speak to the strategy of an electric utility using SMRs, but to your point, I would think the idea would still be base load. Build a site with the potential for more SMRs to be built to meet demand in the future.
ok so i get what you’re saying here.
But there is a fundamental thing with nuclear power, where the “burn up” of nuclear fuel doesnt change. In a submarine it doesn’t matter because you’re backed by a military force and you use 70-80% or 90+% enrichment, where as on land we have 3-5% upwards of 20% for the higher enrichment stuff these days i believe.
In the water its about safety and ensuring power production, on land it’s about ensuring reliable and efficient power production. The only beneficial way of doing this is electricity storage. If you’re nuclear reactor isn’t producing power and has fuel, you are quite literally burning money. Think about it like diverting gas/coal input into a gas/coal fired power plant when power demands lower, as opposed to just lessening the consumption.
But yes it would be about 100% baseload first and foremost, everything else is a future concern, eliminate as much static load as you can and then deal with the rest in other manners.
Yeah I’m with you. I have a senior license at a US nuclear plant just for some background as I don’t know yours. What I’m saying is that I can see value of multiple, say 300MW SMRs at a single site, that can go from 0-100% very quickly compared to current 900-1100MW reactors. So the idea would be you could have a plant in Mode 3 Hot Standby ready to raise power for peak loading. Ideally you’d have at least one reactor online at all times that provides its own in house loads and the standby in house loads that would be quite low. That is the value I see.
The issue at that point would be refueling and maintenance outages. It seems ideal that the design would need to support online refueling and enough loops/system availability to do the majority of plant maintenance online. In addition, the regulatory landscape has a lot of momentum to allowing plants to move to risk informed tech specs which allow for major equipment outages in modes of applicability. If the industry as a whole can agree on a handful of SMR designs with multiple capacity options, it really could be a stop gap to hopefully fingers crossed fusion power in, I don’t know, 50-100 years from now? My two cents.
Renewables being unable to do base load is just a myth that has been debunked countless times.
I’ve love for just one of the people anonymously downvoting to chime in. What you wrote is completely accurate but every nuclear-themed post here and on Reddit is downvoted without anyone putting forward a counter-argument.
Surely there wouldn’t any astroturfing be going on here, would there?
I don’t think it’s astroturfing, it’s just cognitive dissonance. Lots of people were raised thinking that nuclear power was the future and they can’t let go of that. That’s why they downvote without commenting - there’s no factual case for new nuclear and that goes double for SMRs.
there’s no factual case for new nuclear and that goes double for SMRs.
there absolutely is. It’s a good transitional source of power that we currently understand very well, and know how to manage, but simply cannot build. It would be a very prudent way of ensuring some “insurance” time before fusion starts being even remotely viable.
Although i don’t think SMRs are the correct answer here.
It’s a good transitional source of power
Not with the design and build times new nuclear has. It can take 10-15 years to build a plant, and during that time costs will usually spiral and schedules will slip. At the same time, renewables and storage will have gotten even more competitive.
No, it’s because it’s an off topic tangent. We’re talking about SMRs doing not-baseline. Not renewables doing baseline. The very fact they brought it up is indication of binary thought patterns like team sports thinking. “They are for this one thing I don’t like, therefore they must be against the thing I do like!” kind of thing. False dichotomy.
Apparently it’s also false on top of that. Go figure.
here https://www.pnas.org/doi/full/10.1073/pnas.1610381114 we can talk about this, feel free to put forward counter arguments, the gist of the cited paper is that previous studies claiming 100% renewable baseload is possible requires sketchy manipulation of the expected demand as well as currently unavailable storage technology on an almost impossible scale. We’re working on all kinds of storage solutions but the reality is we’re not there yet. I’m rooting for molten salt storage or compressed gas storage rather than ramping up more lithium battery storage. Flow batteries are promising as well, but in any case we won’t have enough storage or transmission capability to have a 100% renewable baseload in the next couple of decades.
Looks like someone beat me to it :)
“In sum, Clack et al.’s analysis is riddled with errors and has no impact on Jacobson et al.’s conclusions.”
renewables can theoretically do baseload. The problem with renewables is that they don’t really have a good pairing with something that would make it SIGNIFICANTLY easier to do.
Nuclear and solar power would make a great pairing for summer time midday peak draws for example. Wind is a good supplementary source. Hydro is a good stored energy source.
You can definitely do full renewable but it will still inevitably be better complimented by some form of baseload plant (i.e. nuclear)
This is only partially true, France for example has standardized its reactors in the past, with a lot of success, and is planning to do it again for the new projects which are planned in the 2030s. Now it was done in the past with little care for local populations and so on, so we’ll see how it goes. What is true though is that standardization also makes sense when there is a repetitive market foreseen. New nuclear project tend to be announced in small numbers, due to the difficulty of investing so much capital at a time, which makes standardization difficult. Smaller reactors may help, but I remain sceptical with the tech.
Can we not standardize the big ones? Their only dependent factor is a big enough water source for cooling, right? Everything else is just land space and supplies.
The construction projects themselves also typically require upgrades to local infrastructure. I live near the failed nuclear project in SC and they had to upgrade rail infrastructure near my town, they had to build multiple new bridges over the railroad because the clearance wasn’t high enough for some of the prefabricated components that had to be transported to the site by rail, etc.
They also depend on a final nuclear disposal site.
Yes and no. Currently the rules around nuclear plants are so strict that each installation becomes bespoke, because small changes that are the reality of construction need to get reapproved.
If regulatory bodies were more open to approving acceptable ranges, or being proactive in the design process we could have more standardized designs.
I think the scale of the projects and the amount of time it takes to build gives people time to work things in to the plans. I also imagine it’s affected by the local supply chain.
That being said I’m more on the fence about them after reading about some of the challenges involved in making them economical. Can you imagine a factory recall on a reactor part? And that’s not even talking about nuclear waste disposal which we still haven’t figured out reliably beyond “stick it over there and hopefully it won’t be a problem for a few hundred years.”
They have only one small drawback, which is that they’re nothing but vapourware.
Sadly! I’m not in this field but I had a professor at uni who was involved in these. I wish they were more prevalent
And why do you think they’re not?
What I’m trying to say is that I’m a fan of the concept despite not being an expert.
To my understanding we don’t have an energy problem. We have a problem of industrialization in combination with global capitalistic tendencies. No wonder the article mentions the following:
The International Energy Agency, which outlined what many experts say is the world’s most realistic plan to decarbonize, sees a need to more than double nuclear energy by 2050.
Also, taking into consideration how dangerous nuclear accidents are, not only I don’t feel any safer with this technology -no matter how much it is praised- I feel literally scared when I hear statements like:
But a nuclear renaissance is coming, the IEA says.
Also, taking into consideration how dangerous nuclear accidents are, not only I don’t feel any safer with this technology -no matter how much it is praised- I feel literally scared when I hear statements like:
you should look into the stable salt reactor design.
Passively safe, inherently contained, and even when catastrophically failed, not a major concern. Many gen IV designs adhere to these sorts of principles. They’re just inherently safe now. The only way you can fuck them up is by actually just becoming a problem.
Nuclear waste storage is still a problem, but greatly reduced with fast reactor designs. For numerous reasons i won’t get into right now because this comment would be three pages long otherwise.
And besides, if you live near a coal plant you are actively consuming more harmful pollutants than if you were near a nuclear plant. Fun fact the japanese government evacuated people into areas WORSE than the initial areas they were in. This was due to gross negligence, but it was such a minor dosage, it basically didn’t matter anyway.
The risk of anything whatsoever happening to any given individual from nuclear is miniscule compared to the very real risk to literally everyone everywhere posed by coal and gas power…
We’re all on a runaway train barreling towards catastrophe, and you’re essentially saying the bathroom needs a floor mat so someone doesn’t slip and fall. That’s about how the risks compare
If that’s your take on my comment(s), I would suggest you take a 2nd look at them.
statistically they have a point. Coal mining has killed SEVERAL orders of magnitudes more people over its history, even oil and gas are relatively dangerous compared to nuclear. Nuclear is inline with both wind and solar roughly with the amount of yearly sustained injuries.
Personally, I don’t care about these statistics. The point I was trying to make was that under capitalism any industry has the goal to make huge amounts of profit. Coal, nuclear you name it. Nothing is about sustainability, unless it is related to greenwashing. So I don’t trust their approach, including the safety of these places. Also the need for more power is for industry expansion, not to heat our homes for instance.
[By the way, I am not a communist. Mondragon is a model of non-capitalistic industrial development that has been successfully expanding since the 1950’s. By no means am I saying their approach is perfect, nor that perfection is the goal. Their example is important tho cause we can learn from them. For the Cleveland Model, they used Modragon’s input. They refers to Gar Alperorovitz amongst others]
fair enough i guess. You’ll be mused to know that nuclear is just about as unprofitable as it gets. So maybe that will rouse some feathers so to speak.
Realistically, i agree with you, get rid of all humans, no more sustainability problems. Problem solved.
The problem as I see it is all your statements are “I feel” and “I fear” with no sources about anything either way.
The following is related to SMRs:
And on the problem of Indutrialization some elements can be found here:
What Are Some of the Drawbacks of Industrialization? - InvestopediaSummary of “Seventeen Contradictions and the End of Capitalism” by David Harvey
Would the above satisfy you @JungleJim?
It certainly seems like there’s a point you’re making instead just “the sky is falling” so yes, thank you.
“SMRs — which are smaller and less costly to build than traditional, large-scale reactors”
They somehow forgot to mention a few key things:
They don’t actually exist yet.
They may be cheaper but they generate way less power. If you added up the cost of enough SMRs to equal one conventional nuclear plant they would be even more expensive than an already prohibitively expensive method of generating power.
What a dumb article.
They exist, what do you mean? We’ve been powering a fleet of submarines with them since the 1950s.
Yeah, it’s going to cost a lot upfront to get them commercially viable, but for the few places where renewables need assistance, I don’t see why this can’t make sense.
They exist, what do you mean? We’ve been powering a fleet of submarines with them since the 1950s.
I’m talking about methods of power generation that contribute to the grid. I thought that was obvious, my bad.
Yeah, it’s going to cost a lot upfront to get them commercially viable, but for the few places where renewables need assistance, I don’t see why this can’t make sense.
They will never be commercially viable. The reason we have always built the biggest nuclear plants feasible is because that was the only way that they made any financial sense.
One significant benefit of these would be the lack of transmission losses that plague massive plants which have to send electricity sometimes hundreds of miles. Having smaller units maintained by municipalities would be cheaper for cities far from major electrical plants.
I was curious, so I checked to see the current longest ultra-high voltage dc transmission line:
The Changji-Guquan ultra-high-voltage direct current (UHVDC) transmission line in China is the world’s first transmission line operating at 1,100kV voltage.
Owned and operated by state-owned State Grid Corporation of China, the 1,100kV DC transmission line also covers the world’s longest transmission distance and has the biggest transmission capacity globally.
The transmission line traverses for a total distance of 3,324km (2065 miles) and is capable of transmitting up to 12GW of electricity.
As a general rule of thumb, HVAC lines will be somewhere around 5-6% line loss per 1000kms, and HVDC somewhere around 3%/1000kms
You could make the same argument for renewables though, and they’re much, much more inexpensive.
Depends on many factors. Solar would be useful if the area had extensive terrain that could serve the city, however, in northern latitudes winter would be challenging with short days and low angle sunlight. If the situation allows, wind power could be useful, when the wind is blowing. The fantastic thing about these units is that they’ll crank out the KW day, night, no matter the season or location. They are not restricted to large generator farms with the scale of upkeep and maintenance they require. A city could be isolated in challenging remote areas and be self sustaining for their energy needs. These aren’t meant to be a “fix-all” solution for every situation, but they make tremendous sense in many applications where current methods are not ideal.
I get what you’re saying but we really should move away from needing power to be generated locally. High voltage DC can move power across huge distances with minimal loss - https://en.wikipedia.org/wiki/High-voltage_direct_current
We don’t need new nuclear in the US, we need the government to get off its ass and mandate an upgraded national grid so we can send power to wherever it’s needed. We already have the perfect conditions in the south for solar and the midwest prairies for wind, as well as offshore. Couple those with storage and there really is no case for SMRs outside of them being a way for fossil fuel companies to justify continuing to kill the planet while we wait for “the next big thing in nuclear power”.
Except long distance power transmission losses are not minimal. Depending on many factors, losses can easily be in the 5% - 10% range. With the amount of energy going through those wires, that’s HUGE. The additional complexity and inefficienies of relay stations, all add up. Having worked in the power sector for nearly a decade, I knew engineers who were celebrated in being able to squeeze an improvement of tiny fractions of % efficiency, as that resulted in millions of dollars saved throughout the year.
Are you referring to AC or HVDC?
Electricity from HydroQuebec comes from hydro dams in the north (James Bay and Churchill, Labrador) of the province to interties at the US border.
In my own province of Manitoba, there are three sets of high voltage direct current (450kVdc) lines that go between 900kms and 1300kms to population centres and the US border. The first one built in the early 1970s.
There are a number of HVDC lines in the US too, California has some that have been in service for 50+ years.
ok so, minor addition here.
Both ac and HVDC are relatively efficient forms of power transfer.
The problem with AC is the skin effect (tl;dr is that the current is carried around the edge of the conductor, not the center, though you can cheat this as well) And the fact that AC running in a submarine cable is going to essentially act as a capacitor, and cause problems. (large losses)
AC traveling through the air doesn’t have this problem. The skin effect is less pronounced than you think because you can just use a higher voltage since it requires less current (transformers also have really good efficiencies when not saturated or undergoing other shenanigans) Also you can design the cabling to abuse this, using outer strand conductors, and then an inner structural strand, to strengthen the line.
HVDC is particularly applicable in undersea cables, due to the capacitor thing just not existing. Making it actually viable. It’s applicable above ground, but the problem is transforming between AC to HVDC and then back to AC. There are reasons to do this, for instance you may be between two grids with two different frequencies, this is the only solution in that case. You may want the grids to be able to operate semi independently (again frequency related)
The big problem with HVDC is that it’s inevitably more complicated. Prior to micro electronics we would use vacuum tubes, or prior to that, two motors linked end to end, one run on AC the other generating DC, and then duplicate that in reverse on the other side (that was also how we used to do voltage conversion in DC systems IIRC)
These days we just use semiconductors, but carrying a lot of power is hard, and expensive. (and also not perfectly efficient) There’s a reason massive boxes of copper wire and mineral oil are the standard solution. Dead simple, easy to maintain, and they quite literally just work.
Thanks for the info, interesting!
I heard about a plan to use HVDC to move solar power from Morocco all the way to the UK.
https://www.wired.co.uk/article/the-uks-wild-plan-to-use-a-giant-cable-to-catch-sun-from-the-sahara
If that’s feasible then moving solar power from Arizona to Minnesota or wind from North Dakota to New York seems feasible. One criticism of renewables is that the sun doesn’t always shine and the wind doesn’t always blow but it’s always sunny and windy somewhere and we can move that electricity around with HVDC, lessening the need for storage.
but it’s always sunny and windy somewhere and we can move that electricity around with HVDC, lessening the need for storage.
this is true. But the technicalities present are immense and would require some significant mathematical modelling in order to optimally determine the solution.
The primary issue with long distance transmission is that unless it’s one singular line, it’s really difficult to know where power is going. It’s realistically going to take the path of least resistance, but what this path is, where it is, and where it goes is complicated. If you have a long distance transmission line from point A to point B it’s much much simpler and a lot easier to deal with.
A particular example would be alaska, particularly farther north, where the sun gets really bizarre in the winter. That’s a prime candidate for anything that isn’t solar basically. Wind might even be problematic with the temperatures there. Nuclear however? Great starting point.
It’s hard to phrase it, but basically. hyper local generation is going to be more important than long distance transmission with renewables, particularly wind, it’s just more efficient that way. Even if norther solar panels produce less power than more southern panels, it might actually make sense to have them there, due to transmission complexities, losses, and just general shenanigans. (if one significant transmission line goes down an entire grid can fail)
If you were to just plonk down a plant in arizona for instance, and hook it up to the local grid. That power is going places. Where exactly? Nobody knows! It could be literally anywhere within the grid! Heres a particularly good demo of this
You could very well export lots of solar and wind, but honestly, i think it’s just going to be more feasible to properly manufacture nuclear power, until we can get fusion power to be a thing that exists. It’s stable, flexible, and we know it’ll work. As anybody would in CS would tell you, it’s a heuristics problem, and heuristics suck. They’re relatively accurate, and give good information, but they are a pain in the ass to develop. Though i guess if solar manages to do that for cheaper it just doesnt matter lol.
(also in case you’re wondering, they’re using HVDC cuz it’s undersea transmission. They might also run at different frequencies? I dont know.)
Hey if you spiritual but not religious types could not fuck this up like the boomers did we would all appreciate it. I get it, you got pyramid power and The Secret. I don’t care. That is your concern. Once you start shilling for OPEC it becomes our concern.
SMRs are interesting.
Frankly i just think we need to take SMR tech and scale it up to stationary plant size. I realize thats a big ask, but it’s already a big enough ask to make SMRs a thing that exist and work. Plus a whole plant is more inline with existing regulations.
Also worst case scenario, it’s just normal nuclear plants. Instead of a bunch of small ones. We have a bunch of big ones, but with standardized designs.
Big Bespoke Reactors? Isn’t that what we do now?
I thought the entire advantage was to be small and use multiple.
- Construction is cheaper because you can gear up a factory to make many of the same thing
- Assembly is cheaper and more reliable because you have more complete modules shipped in for less site assembly
- Sizing is cheaper because instead of designing for the specific site and specific needs, design for how many standard modules you want
- Enhancing is cheaper because a smaller unit is easier to fit into whatever situation you have than to redesign the whole thing
- Maintenance is cheaper because taking one offline is less of a hit in total power generation
the world’s first floating nuclear power plant
That’s a weird thing to say, considering we’ve had nuclear power plants inside submarines since 1958.
Yeah, it’s pretty common for subs/ships at Pearl harbor to supply power back to the Hawaiian grid in the case of a blackout.
It honestly could be done at any naval base, but most of them would not be able to meet the needs of the larger urban areas they dock at.
Ah, but they’re not floating. They’re sinking, but controlled sinking.
The special thing about submarines isn’t that they can go underwater. It’s that they can come back up.
