The Weekend Wonk: Small Reactors Step Out. Can They Overcome Hurdles?
June 4, 2022
Hear me out for a minute.
We’re going to see American versions of small modular nuclear reactors sometime in the 2028-30 time frame, with good luck.
The first unit, probably the first few units, are going to be producing electricity that is quite a bit more expensive than where wind and solar are right now.
The business case for SMRs has been that, they will be mass produced, in factories with assembly lines, and thus create economies of scale. That’s a bedrock principle of economics – mass production brings prices down. We’ve seen it with flat screen TVs, computers, hard drives, iPhones,..well, maybe not iPhones, but you get what I mean. We’re seeing with EVs right now.
So my question is, how many nuclear reactors do you have to produce to get to that economy of scale?
Hundreds? Thousands? Honestly, help me out. I don’t know.
But to make it happen, somebody has to finance the construction of those first hundreds or thousands of reactors. (we’ll need thousands if we expect them to make the dent in carbon emissions that developers hope)
You get the problem? I spoke to Arjun Makhijani PhD about this a couple years ago – he’s President of the Institute for Energy and Environmental Research, and has an Electrical Engineering PhD from Berkeley. He’s thought about this stuff a lot, and he likens the supply chain for SMRs to that for airliners, which seems like a fair comparison.
The leading U.S. developer of SMR technology went public last month, the first company of this kind to do so. The revamped NuScale Power entered the stock market May 3 after merging with a special purpose acquisition company Spring Valley Acquisition. NuScale is the farthest along in the Nuclear Regulatory Commission’s approval process of any company developing SMR technology.
John Hopkins, NuScale president and chief executive officer, said during an announcement of going public that being the first publicly-traded company to design and deploy SMR technology was “a historic moment” for the company, enabling it to accelerate its “efforts to help meet the world’s urgent clean energy needs.” Fluor Corporation is the company’s majority investor.
But reactions to NuScale being traded on the New York Stock Exchange have been mixed. Some analysts have heralded the prospects of the company’s small reactors helping to meet clean energy goals with carbon-free nuclear power in the U.S. and abroad. Others insist that NuScale’s reactors are just a smaller version of the current dangerous and costly nuclear power plants, which create long-lived radioactive waste.
Ahead of competitors
The company is ahead of its competitors in the SMR space because it is using existing light water reactor technology but it is also “fighting against economies of scale,” said Edwin Lyman, the Union of Concerned Scientists’ director of nuclear power safety. While this kind of SMR at 77 MW is less expensive than a large light water reactor, the electricity from the SMR is more expensive because its projected costs are steep and far less power would be sold, he added. That is causing NuScale to look to “cut costs to the bone,” compromising safety, he said.
Arjun Makhijani PhD and M.V. Ramana in Environmental Working Group:
Nuclear reactors are large because of economies of scale. A reactor that produces three times as much power as an SMR does not need three times as much steel or three times as many workers. This economic penalty for small size was one reason for the early shutdown of many small reactors built in the U.S. in the 1950s and 1960s.
Proponents of SMRs claim that modularity and factory manufacture would compensate for the poorer economics of small reactors. Mass production of reactor components and their manufacture in assembly lines would cut costs. Further, a comparable cost per kilowatt, the argument goes, would mean far lower costs for each small reactor, reducing overall capital requirements for the purchaser.
The road to such mass manufacturing will be rocky. Even with optimistic assumptions about how quickly manufacturers could learn to improve production efficiency and lower cost, thousands of SMRs, which would all be higher priced in comparison to large reactors, would have to be manufactured for the price per kilowatt for an SMR to be comparable to that of a large reactor.
If history is any guide, the capital cost per kilowatt may not come down at all. At a fleet-wide level, the learning rate in the U.S. and France, the two countries with the highest number of nuclear plants, was negative – newer reactors have been, on the whole, more expensive than earlier ones. And while the cost per SMR will be lower due to much smaller size, several reactors would typically be installed at a single site, raising total project costs for the purchaser again.
Mass manufacturing aspects
If an error in a mass-manufactured reactor were to result in safety problems, the whole lot might have to be recalled, as was the case with the Boeing 737 Max and 787 Dreamliner jetliners. But how does one recall a radioactive reactor? What will happen to an electricity system that relies on factory-made identical reactors that need to be recalled?
These questions haven’t been addressed by the nuclear industry or energy policy makers – indeed, they have not even been posed. Yet recalls are a predictable and consistent feature of mass manufacturing, from smartphones to jet aircraft.
The problem is not merely theoretical.
One of the big economic problems of pressurized water reactors, the design commonly chosen for light water SMRs, including the NuScale design, which has received conditional certification from the Nuclear Regulatory Commission, was the need to prematurely replace the steam generators – the massive, expensive heat exchangers where the high-pressure hot water from the reactor is converted to the steam that drives the turbine-generators. In the last decade, such problems led to the permanent shutdown of two reactors at San Onofre, in Southern California, and one reactor at Crystal River, in Florida.
Several SMR light water designs place steam generators inside the reactor vessel (Figure 1). Replacement would be exceedingly difficult at best; problems with the steam generator could result in permanent reactor shutdown.
Source: Glaser et al. 2015
We have already seen problems with modular construction. It was a central aspect of the design of the Westinghouse AP1000 reactor, yet the AP1000 reactors built in the U.S. and China have had significant construction cost overruns and schedule delays. In 2015, a former member of the Georgia Public Service Commission told The Wall Street Journal, “Modular construction has not worked out to be the solution that the utilities promised.”
The track record so far points to the same kind of dismal economic failure for SMRs as their larger cousins. Figure 2 shows the capital cost escalation for the proposed NuScale reactor and actual costs of two foreign SMRs. As a result, the total cost of a proposed project in Idaho using the NuScale design has already risen from around $3 billion, in 2015, to $6.1 billion, in 2020, long before any concrete has been poured.
And one more teensy thing.
Climate Denial Crock of the Week 
June 5, 2022 at 5:56 pm
You can’t compare nuclear, wind and solar using Lazard’s LCOE numbers. These numbers do NOT take into account the cost of land needed or transmission infrastructure. Also, there is no way that the value of additional wind and solar is the same for when you have a small amount like 5% and when you’re saturated at 30 to 40%. Arjun Makhijani needs to watch this video:
June 6, 2022 at 7:56 am
As usual Mike is full of it, again with one of those itty arguments that periodically make the rounds in the denying delayalists’ ARF industry and are suddenly everywhere.
LCOE also doesn’t take into account the enormous subsidies given to fuels—more than 100 times clean safe cheap renewable energy’s. And externalities are even bigger, vastly underestimated by the IMF at about $6 trillion a year for fossil fuels globally (doesn’t count military expense of oil wars, for instance, mostly spent by the US). It’s incalculable in the case of nukes; building more of any kind, at even 0.1% of the scale and speed needed to avoid climate cataclysm (elimination of emissions by 2030) would make shoddy work and disasters inevitable. In the US, despite the $100 million a year Price-Anderson Act, insurance coverage is criminally pitiful, and any even semi-worst-case disaster could cost the people of the US trillions.
In the case of nukes, LCOE also doesn’t account for the financing of the huge, nearly-universal, huge delays and huge cost overruns involved, the extra security involved, or many other costs clean safe cheap renewable energy doesn’t have but nukes do.
In case society decides to care, nukes require as much or more land and new transmission as clean safe cheap renewable energy, since clean safe cheap renewable energy can be largely distributed solar, offshore wind (near population centers), built on old fossil fuel facilities and wrecked land, floating solar on existing and new hydro and pumped hydro storage, geothermal, tidal, etc.
But in truth the US is ruled by oligarchic corporate profit- and power-addiction, where considerations like public health, land tyranny, wildlife devastation, lost lives, inequality, etc. don’t matter 1 tiny bit to those making the decisions. If they did, nukes and fossil fuels would have been replaced long ago by clean safe cheap renewable energy.
https://cleantechnica.com/2012/08/03/oil-gas-over-13-times-more-in-historical-subsidies-than-clean-energy/
Note: The pie doesn’t include any coal subsidies, which are also enormous.
Nook boosters typically point with puffed up chests to France when arguing against clean safe cheap renewable energy. Of course, they have to; while at least 65 countries get most of their electricity from clean safe cheap renewable energy, France is the only country in the world with more about half its electricity* (and 16% of its energy) provided by…
oh wait, half of France’s nukes are shut down for emergency & scheduled repairs now, having been found to be ticking bombs. France is being forced to buy power from other countries in the middle of this larger emergency, causing more fossil fuel burning, since ARF’s lies have given cover to politicians and industry slowing the replacing of fuels with clean safe cheap renewable energy. One might wonder if the shutdowns were strictly necessary; I mean, who really cares if failing pipes release massive amounts of radiation?
Study of likely costs of a nuke disaster kept secret…in France
The likely range of the cost is ⅓ to 3x France’s GDP (almost 6 trillion Euros)
They were afraid people finding that out would end the French nuke industry so they lied, cutting the lowest estimate by ½ for the public report.
Weather (wind direction) is what matters most.
At Fukushima winds pushed 80% of the radioactive cloud out to sea. If it had swept over Tokyo, the disaster would have been unimaginable.
businessinsider[DOT]com/potential-cost-of-a-nuclear-accident-so-high-its-a-secret-2013-3?r=US&IR=T
If it’s perfectly predictable and absolutely preventable, is it really an accident?
* The great industrial powerhouse Slovakia, and Ukraine are the only other countries getting more than half their leccy from nukes, and we’ve seen yet another horrific risk that’s caused.
ARF: anti-renewable fanatic
shdullp: shill? dupe? Who knows?
Mike should stop spreading nonsense.
June 6, 2022 at 8:42 am
June 6, 2022 at 9:46 pm
Mike you need to go educate Texas. You know that liberal state full of green deal loving commies. Texas power plant investors keep building more GWs of renewables than gas and nuclear each year and in the future. Just explain to them about how Lazard’s LCOE numbers just don’t take things into consideration. How Armageddon is just around the corner because of just to much wind and solar.
June 6, 2022 at 9:55 am
Canman offers no alternative to LCOE, which is by far the best measure of the worth of energy. (I’m not wasting an hour+ on what’s far too likely a silly conspiracy video; even if there’s an alternative in there, I’m sure it’s as stoopid as it obviously is unnecessary. We’re going to see a lot more such sour graping from the losers in this struggle, and the unmoored paranoid lunacy* of the far right will determine its form.)
All energy in a capitalist system is subject to supply and demand, although only nominally, since subsidies and externalities (subsides by any other name) are so HUGELY in favor of fossil and fissile fuels it’s warping all of civilization. So, the alleged value of nuke energy is equally diminished by an excess. To lie by pretending that’s a fault of only clean safe cheap renewable energy is despicable. And opposing necessary transmission and storage is what creates the problem of curtailment in the first place. (It’s much worse for nukes since they don’t follow load, and if they did, it would only intensify their economic death spiral.)
Solar + wind + far less storage than most people think + just enough transmission + targeted demand response takes care of what might otherwise be thought of as “excess” supply. (Although I don’t know what would constitute “excess” or “too-cheap” renewable energy in a world of such privation. The idea only reveals the fundamental corruption of Wetiko-generated capitalism.) Solar + wind + storage is still cheaper than nukes, as we see from the chart above. And even then, LCOE and the chart don’t account for the complementarity of wind and solar; both are more valuable when used together and storage etc. is less necessary.
As I keep pointing out over the heads of trolls like Mike, clean safe cheap renewable energy all works synergistically. Tracking their price singly is necessary, but leaves out the benefits of orchestrating them to provide all our needs at the lowest cost financially, socially, ecologically, psychologically, and in every other way. That can’t be done in a measure, only in a complex sophisticated study. Like the dozens that have shown clean safe cheap renewable energy is the only possible path to prevent eco-socio-psychological Warmageddon.
DERism
Rooftop solar and home batteries make a clean grid vastly more affordable
Distributed energy is not an alternative to big power plants, but a complement.
David Roberts
https://www.volts.wtf/p/rooftop-solar-and-home-batteries?s=r
* paranoia is one’s own hostility projected into others.
June 7, 2022 at 11:58 am
“I’m not wasting an hour+ on what’s far too likely a silly conspiracy video; even if there’s an alternative in there, I’m sure it’s as stoopid as it obviously is unnecessary.”
Ah yes, Lazard give you numbers that you want to hear. You don’t want to rock the boat by using the scientific standard of checking all the things that might falsify an answer.
June 9, 2022 at 7:52 am
So boring. Obsessively ignore everything that proves the claim wrong, relentlessly hawk the cherry-picked, counterfactual nonsense it rode in on, attack everything projected onto everyone else involved. Then do it again. Canman can stop now, be satisfied that the long attempt to bring on the now virtually certain near-future end of most life on Earth and most of humanity Canman has succeeded.
“The Benefits of Local Solar + Storage Are Not Integrated in Traditional Models”
Click to access LocalSolarRoadmap_FINAL.pdf
No one said that LCOE alone provided all the information we need to make a decision. That would be absurd. In no field is one fact or number sufficient for everything. But LCOE is by far the best measure of an energy source’s cost, and attempts to dismiss it are like soooo many denying delayalist, ARF, anti-evolution, and other anti-science lies.
I answered Canman’s programmed crocodile tears with overwhelming extra-LCOE information evidence showing the claim is exactly the opposite of the truth. Canman ignored the evidence, as always. Fossil and fissile fuels kill many times more wildlife. They kill far more people. Far more land is destroyed and contaminated by fuels. The biosphere is being melted down by fuels. Democracy is turned into autocracy by fuels. And we know—because we have LCOE as a measure—that we have to pay rich people more money for all those things than we would if we switched to 100% clean safe cheap renewable energy.
It would be nice, just once, to get an honest argument from the ARFs, and an honest reason why Canman or any of the other ARF trolls do this; too bad that will never happen. Revealing their real arguments and motives would destroy their arguments. What a waste of lives.
June 11, 2022 at 10:18 am
Here’s the 60 second version:
June 6, 2022 at 8:36 pm
[I’ve stopped listening to promises about nuclear power technology years ago. In the 1970s a family friend waved away the issue of nuclear waste because it was all going to be encased in glass and buried.
In the 1980s the township where I was living had higher electricity rates than the surrounding towns because its utility had invested in nuclear power plant that opened late and over budget. Now we have people telling boring stories of Glory Days of the French reactor fleet, when even France can’t build a new one without major time and budget overruns.]
Siting criteria for thermal power plants have their own costs, too., the biggest involving cooling water access.
Solar plants can be installed on brownfields, over factories, over pastures, on campus roofs, over parking lots, over canals, over reservoirs, over highways, etc. Solar arrays are so quick to install and take down that an uncommitted landowner can negotiate shorter-term leases.
Onshore wind farms, as we know, integrate happily with agricultural land and rural counties, while offshore wind farms just have to stay out of the sea lanes, and maybe far enough that rich people don’t have to see them.
In any case, I don’t have to make the decision about what power plants should be built where because the investors have already decided they usually get quicker returns for building solar and wind farms than from thermal plants, including retiring FF-based plants early to replace them with PV solar.
June 5, 2022 at 9:05 pm
This is a paper that was recently (May 31, 2022) published in the Proceedings of the National Academy of Sciences. Note that one of the authors is Allison Macfarlane, who is a former head of the U.S. Nuclear Regulatory Commission.
Nuclear waste from small modular reactors
Significance
Small modular reactors (SMRs), proposed as the future of nuclear energy, have purported cost and safety advantages over existing gigawatt-scale light water reactors (LWRs). However, few studies have assessed the implications of SMRs for the back end of the nuclear fuel cycle. The low-, intermediate-, and high-level waste stream characterization presented here reveals that SMRs will produce more voluminous and chemically/physically reactive waste than LWRs, which will impact options for the management and disposal of this waste. Although the analysis focuses on only three of dozens of proposed SMR designs, the intrinsically higher neutron leakage associated with SMRs suggests that most designs are inferior to LWRs with respect to the generation, management, and final disposal of key radionuclides in nuclear waste.
https://www.pnas.org/doi/full/10.1073/pnas.2111833119
June 6, 2022 at 11:37 am
SMRs require water for steam generation. and possibly for steam condensation. Where’s the water?
https://www.nuscalepower.com/benefits/reduced-water-consumption
“Where water is scarce, NuScale can support multiple options for an air-cooled design, which can reduce NuScale VOYGR plant water consumption to as little as 1.1 gal/MWh; significantly less than the most efficient water-cooled combined cycle plants.
Even with a typical wet cooling design, a NuScale VOYGR plant would consume less water annually than a typical large nuclear power plant simply because of its smaller power output”
June 6, 2022 at 8:41 pm
Arjun Makhijani addressed the extra expense and/or inefficiency of air-cooled plants, and remember that every product variation adds its own cost to production.
The marketing language on NuScale’s web site doesn’t show the extra cost.
June 6, 2022 at 12:51 pm
An interesting article about Nuclear waste from small modular reactors, NuScale being one of them.
https://www.pnas.org/doi/10.1073/pnas.2111833119
June 6, 2022 at 12:52 pm
I apologize for posting what someone already did. Don’t know how to delete it.
June 6, 2022 at 7:41 pm
All this hype about “new” small modular nuclear reactors reminds me of something. What was it… Oh yes, here it is. The following is something I sent to some correspondents about seven years ago:
———
Awhile ago I went through a box of stuff and found a magazine I had saved because inside it includes an interesting interview with John Bell on quantum mechanics. However, the main article is highlighted on the cover with the headline “Nuclear Renaissance: Reactors Are Back and Reactions are Good.” This article discusses “the reactor design of the future – the dream machine that’s simple, small, efficient, and, most important, safe enough to convince the American public, once again, to vote nuclear.” The discussion includes “an advanced version of the light water reactor,” “smaller reactors with more passive safety features,” the newest designs – “inherently safe” reactors, “new ALWRs [advanced light water reactors] would be assembled from shop-fabricated modular components, making them cheaper for utility companies to buy,” “three other types of reactors that proponents claim to be ‘inherently safe’ go by the names of integral fast reactor (IFR), high-temperature gas-cooled reactor (HTGR), and process inherent ultimate safe reactor (PIUS),” “Rockwell International and General Electric have already developed two commercial designs for ‘inherently safe’ sodium-cooled reactors,” “engineers agree that PIUS is an elegant design, but that’s all – only a design. It’s still on the drawing boards.”
OK… The thing is… That article on the “nuclear renaissance” is not recent. It’s in an Omni magazine dated May 1988. (1988 was the year of Hansen’s famous testimony to congress warning about climate change.) Today – 27 years later [now 34 years later] – we are hearing pretty much the same sort of delusional fantasies from the nuclear proponents.
———
DO NOT BE FOOLED BY THE BOGUS HYPE ABOUT NEW NUCLEAR TECHNOLOGIES. The nuclear industry makes promise after promise after promise. After decades of promises, they have not delivered on those promises. Are we ever going to wise up and stop giving taxpayer money to them? Are we ever going to start spending the money on cheaper and safer renewable technologies such as wind and solar that we KNOW will work?
June 6, 2022 at 8:45 pm
I generally agree, but would point out that some pie-in-the-sky technologies that would fail in 1990 might be plausible in 2022. Of course, the really impressive advances tend to come from mass-market products. Nuclear power tech is too low-volume, too few competitors and too-long evolutionary turnaround.
June 8, 2022 at 3:59 pm
As I hear it, the NRC is permitted to judge reactors on emissions even below background, as grounds for rejection. Is that right? And where do the costs come from in nuclear; new or old. It’s it servicing the debt on loans while it sits in the ‘in basket’ of the NRC who’s too busy putting finger to the wind rather than science judgment? Diablo Canyon sits on 12 acres. 2 GW of always-on production, would require about 33 square miles of solar panels. And where do those solar panels get deployed? On virgin land otherwise used by wildlife. Of course, we don’t care about wildlife or native ecosystems. Let ’em die for all we care. With no value put on the land, the comparisons are not fair. Our values are screwed up, and that gets piped through the LCOE assumptions. If we really CARED about the future of a life-abundant planet and a sane human population sitting lightly on the land, we might make use of all the thorium needed to power our world that is already sitting around in Uranium mine tailings. And we’d use molten salt thorium breeders to burn the existing nuclear waste and remove that always-on argument from the anti-nuke’rs.
I’m all for solar on existing structures, and wind in already-made crop fields, But NOT on virgin land meant for the other life we share this planet with.
It would be educational to have a big box crate, with nuke-danger symbols all over it, and have the NRC pass their geiger counters over it and throw a fit…. before opening the lid and seeing a ton of bananas with their potassium isotopes.
June 9, 2022 at 12:28 am
From https://www.nrc.gov/reading-rm/doc-collections/fact-sheets/bio-effects-radiation.html
“[T]he NRC does require its licensees to limit exposure to members of the public to 100 mrem (1 mSv) per year above background. Exposure to adults working with radioactive materials must be below 5,000 mrem (50 mSv) per year. NRC’s radiation exposure limits are contained in Title 10 of the Code of Federal Regulations, Part 20.”
June 9, 2022 at 12:40 pm
“Diablo Canyon sits on 12 acres”
Wikipedia: The power-producing portion of the plant occupies around 12 acres
Notice power producing description.
PGE: Diablo Canyon Power Plant, which sits on approximately 1,000 acres on the Pacific coast
My own rough estimate that includes the power producing portion, parking, buildings, cooling, and electrical substations (or whatever they would be called) is around 200 acres.
So, Diablo produces about 80GWh/acre per year
California utility solar about 500MWh/acre per year
June 9, 2022 at 7:28 pm
12 acres is ridiculous. But 200 is also not the truth. The claim is that solar and wind take “virgin land” away from wildlife. So the whole 1000 acres counts, because what’s inside that security perimeter etc. is not wild land, either. It’s been taken by the nuclear industry. Really, Diablo Canyon produces 16 GWh/acre/year, maybe for 60 years, takes 10 years or more to get “decommissioned”, then keeps taking up the land as long as history goes. No matter what true figure you use, solar produces more per acre per year with an infinitesimal fraction of the damage. And it keeps getting better and cheaper while nukes keep getting expensiver and worser. Why would anyone sane support them?
June 9, 2022 at 7:42 pm
“On virgin land…”
Sorry, no.
Solar is being put on rooftops, land wrecked by fossil fuels, urban wasteland, parking lots, highway rights-of-way, reservoirs including pumped hydro storage reservoirs, over battery arrays and on geothermal sites… and now on a whole building, sides and all. https://cleantechnica.com/2022/06/06/melbourne-office-building-clad-entirely-in-skala-solar-power-panels/
Click to access AreaRequiredWindOnly.pdf
Offshore wind turbines (which alone could supply all the energy the world needs, though it’s cheaper and easier to combine them with other clean safe cheap renewable energy sources) take up no land at all. The manufacturing, transmission, etc. occupy a fraction of the land wrecked, essentially forever, by fossil and nuclear fuels. Like fossil fuels, nuke facilities get put on the land of those without the political power to fight them off. Indigenous people especially have suffered almost a century of illness and early death from uranium and fossil fuel extraction and processing, though they’re hardly alone. Fuels attack every organ in the body in multiple ways, cause cognitive and emotional problems (low IQ, aggression, depression, mental illness, dementia…), low birth weight leading to lifelong problems of all kinds, as well as social and political problems including those that are part of the resource curse.
Hinkey Point has been taking up 430 acres for more than a decade (along with 7 other sites, long before construction even started), hasn’t produced a watt, and may never. If it gets built it has a contract to provide power at 1 1/2 times the cost wind and solar are already meeting, and of course W&S keep getting cheaper as nukes get more expensive. Corrupt practices like this contract and the UK nuclear submarine program’s interest are why reactors keep getting built. Well, half built.
At some point as Hinkey Point gets older and more dangerous it will be shut down—we hope before it kills too many people—take a decade or more for what’s euphemistically called “decommissioning”, provide society with massive amounts of radioactive reactor parts and other high-level waste, then spend an eternity in limbo because no one in charge knows what to do with the waste or will admit human society is completely unable to manage the necessary level of care for anything remotely like the necessary length of time. But it’s OK, they’re gettin rich and showin what big men they are.
Nuclear exclusion zones for just 2 of the many disasters take up 2600 sq. miles, and there should be more around Kyshtym and other sites but aren’t, for PR reasons and the needs of autocracy.
Where better and wild land is taken up by renewable energy it’s because oligarchic corporations and the governments corrupted by them have demanded it for the sake of profit.
Blame capitalism.
Done right, clean safe cheap renewable energy takes up far less land than fuels and no wild lands, especially considering the whole life-cycle, and the longer the time-scale considered the more it comes out in favor of renewables. The energy land argument, like all ARF arguments, is a lie, created by professional psychopaths like Robert Bryce and spread by the even worse jackalpack of right wing PR firms funded by Koch, Exxon, et al.
cleanpower[DOT]org/blog/fact-check-bryce-errs-on-emissions-land-use/
June 9, 2022 at 7:46 pm
Take 2: (The site is suddenly doing odd things to my links.)
Click to access AreaRequiredWindOnly.pdf