When a teenager attempts to build a breeder reactor
Dear Dr. Zoomie – I was watching The Man in the High Castle and there was a bit about weapons-grade uranium posing a health risk to people around it. Is this true? //
The short version is that uranium – even highly enriched uranium – is simply not very radioactive. I can confirm this from personal measurements – I’ve made radiation dose rate measurements on depleted uranium, natural uranium, and enriched uranium and none of them are very radioactive. Here’s why: //
. It takes about 100 rem to cause radiation sickness, about 400 rem to give someone a 50% chance of death (without medical treatment), and nearly 1000 rem to be fatal. With a dose rate of 1 R/hr at a distance of 1 meter this part’s easy – it’ll take 25 hours of exposure to cause a change in blood cell counts, 400 hours to give a 50% risk of death, and 1000 hours to cause death. At a speed of 60 mph it takes about 50 hours to cross the US – not even enough time to develop radiation sickness. And that’s for a person sitting for that whole time at a distance of 1 meter from the uranium...
Urenco is an international supplier of enrichment services and fuel cycle products for the civil nuclear industry, serving utility customers worldwide who provide low carbon electricity through nuclear generation. //
SWU stands for Separative Work Unit. It is the standard measure of the effort required to separate U235 and U238.
Choose your relevant calculator from the list below. Enter the known quantities before pressing the calculate button to see the result.
DDopson Ars Tribunus Militum
22y
1,933
Subscriptor
Doc12 said:
If someone has access to industrial centrifuges then HALEU seems like a convenience rather than a necessity. Could use un-enriched uranium in your centrifuges and would just take longer to get to the end point?
Yes, quite a bit longer. If you are a nation-state that can build an industrial scale centrifuge operation, then any reactor fuel is a proliferation risk. It takes several times more effort to concentrate to 5% than from 5% to 90%.
There's a concept called Separation Work Units (SWUs) that can be used to quantify how much centrifuge time is needed to separate x kg of uranium at y% enrichment into an enriched stream at z% enrichment and a tailings stream with <<y% enrichment. And there's a calculator here. https://www.urenco.com/swu-calculator
Let's say you want to produce 1 kg of 90% enriched U235.
Starting from 176 kg of natural uranium, it takes 227 SWUs of effort if you are exhausting tailings at 0.2%. Or if you exhaust tailings at 0.5% it only takes 154 SWU, but then you need a whopping 424 kg of natural Uranium feedstock. Either way, it's a lot of work.
Starting with 20 kg of 5% enriched reactor fuel, drained down to 0.5% tailings, is 48 SWU. Or if you can afford be wasteful of 5% enriched reactor fuel, 30 kg + 30 SWU gets you to the same place with 2% tailings, something that only makes sense if you've stolen the reactor fuel rather than enriching it from natural uranium.
Starting with 5 kg of 20% enriched HALEU drops the separation effort to 12 SWU, assuming 2% tailings. Or if you stole a lot of it, and only need to extract half the U235 content, 10% tailings is 7.4 SWU per kg of weapons-grade HEU.
The key point is that the greatest investment of separation work comes in the early enrichment stages where vast quantities of natural uranium are concentrated into relatively smaller quantities of moderately enriched uranium. It takes several times more effort to concentrate to 5% than from 5% to 90%.
So this risk isn't unique to HALEU. Regular reactor fuel is almost as problematic. //
DDopson Ars Tribunus Militum
22y
1,933
Subscriptor
clewis said:
Timed to the µs? I'll just use a Raspberry π and a real time operating system. If we need ns, I might have to buy some speciality expansion boards.
While modern technology has rendered trivial some aspects of the problem that were much harder in the pre-transistor era, it's still not quite as simple as that. You need high quality explosive initiators that will trigger detonation with a predictable lag, versus all of the default solutions have unacceptably high variability such that one side goes before the other, creating an asymmetric implosion. The solution is often found by driving enormous currents through wires or foil embedded in relatively sensitive explosives, and in 1945, achieving such a rapid current rise was a major challenge. Today, someone developing similar high-precision initiators would benefit tremendously from the plethora of off-the-shelf power electronics (much more important even than the Raspberry pi), but it's still something that a real engineer needs to spend some time testing very carefully or your weapon will dramatically underperform it's designed yield. //
DDopson Ars Tribunus Militum
22y
1,933
Subscriptor
Wickwick said:
Sandia National Labs has (at least) one group which specializes in analyzing the risk of improvised industrial goods for explosive yield. Many years ago I helped adapt some lab equipment so it could be used in a cloud of muriatic acid as if someone had detonated a railcar full of the stuff. Just last year at a conference I was speaking to one of their researchers about the threats posed by things like diesel tankers, LNG ships, etc. None of those things are viewed particularly highly on the threat matrix compared to something like ANFO (Beirut port explosion). Fuels have a lot of stored chemical energy, but you can't couple that to the environment in a manner that creates a large explosion without having an oxidizer intimately mixed in. Achieving the near-nuclear-level blast of a massive fuel-air burst bomb is a non-trivial engineering feat. //
+1, and note that weaponized fuel-air bombs don't just use any old fuel laying about. They have a specifically engineered mix of a highly volatile liquid with a wide detonation range (better tolerance for uneven dispersion), such as ethylene oxide, with a powder like aluminum, which boosts the energy release per unit of oxygen consumed.
Poorly dispersed commercial fuels badly underachieve their on-paper energetic value.
The US is still regulating some enriched uranium based on an analysis from the 1950s. //
High-assay low-enriched uranium (HALEU) has been touted as the go-to fuel for powering next-gen nuclear reactors, which include the sodium-cooled TerraPower or the space-borne system powering Demonstration Rocket for Agile Cislunar Operations (DRACO). That’s because it was supposed to offer higher efficiency while keeping uranium enrichment “well below the threshold needed for weapons-grade material,” according to the US Department of Energy.
This justified huge government investments in HALEU production in the US and UK, as well as relaxed security requirements for facilities using it as fuel. But now, a team of scientists has published an article in Science that argues that you can make a nuclear bomb using HALEU.
“I looked it up and DRACO space reactor will use around 300 kg of HALEU. This is marginal, but I would say you could make one a weapon with that much,” says Edwin Lyman, the director of Nuclear Power Safety at the Union of Concerned Scientists and co-author of the paper. //
Material that’s under 10 percent uranium-235 is called low-enriched uranium (LEU) and is used in power reactors working today. Moving the enrichment level up to between 10 and 20 percent, we get HALEU; above 20 percent, we start talking about highly enriched uranium, which can reach over 90 percent enrichment for uses like nuclear weapons.
“Historically, 20 percent has been considered a threshold between highly enriched uranium and low enriched uranium and, over time, that’s been associated with the limit of what is usable in nuclear weapons and what isn’t. But the truth is that threshold is not really a limit of weapons usability,” says Lyman. And we knew that since long time ago. //
According to his team, an amount between 700–1,000 kg of HALEU is enough to build a bomb with a 15-kiloton yield—roughly as powerful as the Little Boy bomb that destroyed Hiroshima in 1945. Building one of these bombs would be a matter of days or weeks for a rogue country or a terrorist group.
Somewhere along the way, we dropped the original Los Alamos fine print mentioning quantities and tied our security requirements to enrichment levels only. //
Lyman’s team proposes to get back to the Los Alamos study findings and simply classify HALEU as a Category I material in cases when it’s being used in an amount large enough to build a nuclear weapon. “The point of our article is to highlight that pretending HALEU is not weapons-usable could lead to very serious gaps in security if these reactors really become viable and exported to all sorts of places,” Lyman says. //
SFC Ars Centurion
14y
359
Subscriptor++
So you need 1,000Kg to build a bomb. Let's say an armed foreign adversary managed to attack one of these facilities. Exactly how long is it going to take them to both break into the area where the fissile material is being used, get it out of where it's at, and into something to transport it. That is roughly #2,200 lbs we're talking about. Could you do that with a normal moving van? Absolutely. But can you do it in under an hour, without killing everyone involved via radiation poisoning? I'm skeptical. //
GottaSaySomething Ars Scholae Palatinae
7y
1,342
Ed: I totally missed the point. The point of the article is selling it to "iffy" states where you can't control what happens to it. Not it being stolen from the producing country's reactors. //
Quisquis Ars Tribunus Angusticlavius
12y
6,846
Heads up for the discussion:
1 ton of uranium is only about two cubic feet. //
Pueo Ars Scholae Palatinae
10y
1,005
jandrese said:
I think it's more of a case where terrorists also get centrifuges...
HALEU still poses more of a risk if we're worried about covert enrichment because by the time you're at 20% you've already done about 90% of the separative work necessary to reach weapons grade uranium. This means you have only 10% of the signal or 10% of the time available to catch the covert enrichment of HALEU vs the cover enrichment of natural uranium. //
Atterus Ars Tribunus Militum
6y
1,663
Time to end the technological dark ages caused by nuclear fears. Nearly every issue surrounding the tech is the result of government meddling and red tape along with lying about providing a place to store what little waste there COULD be if reprocessing was allowed. All due to unfounded fear mongering largely based on a shitty film, braindead communist planners in Russia, and a journalist that thought it was scandalous concrete had elevated radioactivity... decades of stagnation as a result. //
Nick31 Seniorius Lurkius
7y
6
I was interested in this, until I saw that the only source was from the Union of Concerned Scientists, the same group who specializes in fear-mongering and hysteria with their ridiculous "Doomsday Clock." In this case they seem to be using their hypothetical disaster scenarios to ask for the last thing the nuclear power industry needs: more government regulations.
Our current nuclear regulatory system is resulting in millions of premature deaths and effectively halting any progress on global warming. It must be changed. But to what?
The GKG proposes that nuclear power be regulated by a variant of the same system by which we regulate other hazardous but beneficial activities. We call that system Underwriter Certification (UCert).
This slide deck is the second of two part presentation on UCert. It outlines how Underwriter Certification would be implemented; and explains why it is feasible. All it takes is the political will.
Our current nuclear regulatory system is resulting in millions of premature deaths and effectively halting any progress on global warming. It must be changed. But to what?
The GKG proposes that nuclear power be regulated by a variant of the same system by which we regulate other hazardous but beneficial activities. We call that system Underwriter Certification (UCert).
This slide deck is the first of two part presentation on UCert. It attempts to explain why we must scrap the current regulatory system in which there is an enormous chasm between an omnipotent regulator's incentives and societal welfare.
Councilwoman Vickie Paladino @VickieforNYC
·
We must destroy the environment to save it!
Once every Joshua Tree is uprooted to make room for acres solar panels and the whales and birds are killed by windmills, and electricity is expensive and intermittent for all but the wealthiest, we’ll have saved the planet!
This is all much better than building a few modern nuclear plants.
John Solomon @jsolomonReports
Joshua trees growing for over 100 years will be cleared for solar farm in California https://justthenews.com/politics-policy/energy/joshua-trees-growing-over-100-years-will-be-cleared-solar-farm-california
8:55 PM · Jun 7, 2024
The nuclear establishment never fails to disappoint.
When it comes to spent nuclear fuel, the stupidest thing we can do is argue for deep geologic disposal.
This is trebly idiotic.
1) It puts already mined, valuable material in place whence it is difficult to impossible to recover.
2) It is a horrendous waste of resources.
By making nuclear more expensive, we guarantee there will be less nuclear. Less nuclear means more fossil, more pollution, and more CO2.
3) It convinces everybody that aged spent fuel is uniquely dangerous. Why else would you spend billions of our money in this manner?
In fact, 600 year old spent fuel is just another poison. You must swallow this glass for it to harm you.
Bacon is probably more dangerous. You are much more likely to eat that carcinogen.
This set of slides outlines a plan for handling spent nuclear fuel
which makes sense. The nuclear establishment will reject it,
because they are far more interested in extracting taxpayer money, than they are in providing cheap, pollution free, low CO2 electricity.
This is criminal selfishness.
This slide deck is an introduction to the Sigmoid No Threshold (SNT) radiation harm model.
It depends on the Radiation Damage and Repair presentation.
Under the terms of the sale, Amazon not only acquired Cumulus' datacenter facilities and associated power infrastructure, but has direct — behind the meter — access to a sizable chunk of the energy generated by the nuclear plant's two reactors.
Over the course of its contract with Talen, Amazon expects to unlock upwards of 960 MW of power supply. However, we'll note that the cloud titan has the option to cap this at 480 MW if it doesn't actually need all of it.
We've now learned at least 15 new datacenters will be built adjacent and connected to the fission plant over the next ten years. As we've previously reported, an AWS campus with five buildings may take up 600,000 square feet, or around 13 acres, and capacity of between 50 and 60 megawatts. //
As generative AI has taken off, it's not uncommon to see clusters of 20,000 or more GPUs capable of consuming in excess of 25 megawatts of power, deployed.
This slide deck lays out the fundamentals of DNA damage and repair.
It explains why we are so good at repairing radiation damage,
and the importance of keeping the damage rate below the repair rate.
The information in this deck is a prerequisite for all the other
Gordian Knot Group slide shows.
Under the new plan, however, all such habitats would be categorically off-limits as soon as it is discovered that the land is occupied by a listed species. Any potential impacts to endangered species habitats that are discovered in the course of site surveys (usually after millions of dollars have already been expended on the project application) would kill the project entirely.
The permitting risk, already prohibitive for many new projects, could put whole states beyond the reach of all but the most hardy (or foolish) developers. The solar energy areas under the new solar plan overlap substantially with areas containing multiple endangered and threatened species. This endangered species exclusion alone would eliminate virtually all new solar development in Utah, Nevada, and Arizona, which lead the nation in solar capacity per acre. //
Even for the 14% of BLM land left available for solar project development after all these exclusions, the new plan imposes onerous permitting requirements. These include some 600 mandatory design elements.
Some of these verge on the comical. BLM proposes a blanket prohibition on “grading” (leveling out land), which is indispensable for access roads, utility-scale batteries, transmission poles, and construction staging. The plan also prohibits development within 200 feet of ephemeral streams (those that come into existence, for example, after heavy rainfall, and then go away) and requires 75% residual vegetation around the development.
These requirements will be impossible to meet economically for many projects, and even where possible, would significantly expand the amount of land required per unit of electricity, thus defeating the goal of conservation. //
Most surprisingly, the new plan does not address any of the major problems that years of experience have revealed in the permitting process for solar and other energy projects on BLM land. On the contrary, it makes the permitting challenges even worse for existing projects applications, which are not “grandfathered” in any respect. Many solar project applications already in process will have to start over, and many of those applicants will prefer to cut their losses instead.
Many projects’ applications have been pending for years, and companies have already negotiated operational and power-purchase agreements of various kinds and would be bankrupted by having to start over.
This demonstrates a problem with heavily regulated sectors: Officials feel all too free to “move the goal posts” with little concern for the enormous losses they are causing developers and investors and little understanding that these are social losses that impact everybody.
For Americans to avoid a prolonged period of energy scarcity in the high-demand decade ahead, the nation will require a significant expansion in electricity generation. The bulk of that will need to come from nuclear and fossil sources, which are significantly more abundant, “energy dense,” and reliable than renewable sources like solar and wind. //
The new solar plan is being promoted as a partial solution, but even a brief review shows clearly that it will only make those problems worse. The plan is a clear sellout to left-wing environmentalists. And it shows that while those environmentalists hate fossil fuels, they don’t particularly love renewable energy—or energy of any kind.
They mean to save the planet for what they think is the planet’s sake, not for our sake. And if in the process they plunge the world into energy scarcity—a much grimmer fate than all the doomsday climate scenarios put together—in their minds, that’s just too bad for us.
Anyway, when some champion of human liberty in a Che Guevara T-shirt and Mao jacket was haranguing his audience with claims like “A single Hiroshima bomb set off downtown would annihilate this university and all of us in the blink of an eye”, what better way to burnish one's Strangelovian credentials than to whip out a handy-dandy nuclear bomb computer slide rule, whip—slip—slide, and interrupt, “Naaah…fifteen kilotons at five miles? Surface burst? Why, that's only a quarter to a third of a pound per square inch overpressure—it'll probably break some window glass but that's about it.” Flipping the slide rule over, “The flash isn't even enough to cause sunburn, and the immediate radiation is next to nothing.” For some unfathomable reason, this never seemed to either carry the argument or suitably impress chicks. //
My nostalgia for this particular relic of the Cold War was such that I've had a project to produce an online edition on my to-do list for more than five years. Like many items on this embarrassingly long and all too infrequently shortened list of unrealised ambitions, it's something I half expected someone else to do long before I got to it. This would be perfectly fine with me—I undertake these projects because I want to see them done, and crossing off an item without the wear and tear of doing it myself couldn't make me happier. In fact, scanning (and possibly OCR-ing) The Effects of Nuclear Weapons was an item on my list before the fine folks at Princeton got the job done.
The Web edition of the nuclear bomb effects computer, however handy when you're online, isn't much use when operating under field conditions, in a post-Armageddon environment, or for settling thermonuclear bar bets. Fortunately, with a little time, patience, and access to a suitable printer and office supplies, you can assemble your own pocket slide rule computer, just like the original—no batteries or Internet connection required!
You'll need to be able to print graphics (ideally in colour) from images in PNG (Portable Network Graphics) format with a specified and consistent scale. The rotating discs of the bomb computer must be printed on clear plastic with white areas of the image left clear. Most printers can print transparencies intended for overhead projectors which are suitable for this purpose.
Russia vetoed a United Nations Security Council resolution Wednesday that would have reaffirmed a nearly 50-year-old ban on placing weapons of mass destruction into orbit, two months after reports Russia has plans to do just that.
Carlson and Rogan didn’t moralize over Hamburg, Dresden, or Tokyo. Instead, they bobbed their heads and lamented the use of a particular type of weapon, not the death toll or civilians roasting alive from firebombs.
Even with that horror, Japan was not moved to surrender after Tokyo was set on fire 17 months before Hiroshima and Nagasaki. Japan didn’t surrender after a half million of her civilians had died from conventional bombs. Japan only surrendered when Truman bluffed and assured Japan that her cities would be leveled with more atomic bombs.
When Truman ordered Fat Man and Little Boy to drop on Japanese cities, he saved countless lives, both civilians and combatants. When Emperor Hirohito ordered his country to stand down, he saved countless lives – both civilian and combatants. Both decisions saved the lives of Marines like my father. Men who came back to build lives and raise families. The deaths of civilians at Hiroshima and Nagasaki were regrettable, but the lives of Americans and Japanese were spared because of it. That act was “good” in that the resulting surrender and peace clearly were. //
AdeleInTexas
7 hours ago
Great piece, heartfelt and factual. Carlson's claim that ending the war in Japan by use of the atomic bombs was prima facie evil is prima facie stupidity. //
. I asked him what he thought about the use of the atomic bombs and he was all for it. He just wished they had them sooner.
Gordian Knot News is now up to 100 some posts. They range in importance from fundamental to trivial; in writing quality from pretty good to tech manualese. But it is impossible to figure out either importance or readability from the title.
So I've prepared a list of links, which groups the posts by subject and gives them a grade. The same post can show up multiple times.
A means you must read this to stay in the choir.
B means you should read the piece.
C means read this if you have nothing better to do.
D means don't waste your time.
In many cases, there is a very similar PDF on the Flop Book site, in which case I have also included a link to display that file.
Fear campaigns have led to tight regulation of nuclear power plants and nuclear waste, which means that to see dry fuel casks you have to jump through hoops with security clearance, over-the-top security checks, supervised visits and so on.
I think we should normalise nuclear waste by putting it in public places that allow people to see it. In the Netherlands, COVRA (The Central Organisation For Radioactive Waste) stores all of the country’s high-level waste and is also a public museum and art gallery that hosts many exhibitions.
Inside COVRA: the art of preservation
On a panel in Paris last year, I called nuclear power plants national monuments, and I believe that they are, because they represent clean air, good jobs, and high-quality lifestyles. I think we should decorate nuclear power stations like the mural on the Cruas-Meysse cooling tower in France. We should celebrate what humankind can achieve with clean energy: a high quality of life for everybody, without the negative impacts of burning fossil fuels.
Consider uranium: the underrated element of awe //
Back to energy density: uranium metal really packs a punch. It is 1.67 times more dense than lead, and 1 kilogram of uranium-235 contains 2 to 3 million times the energy equivalent of 1 kg of oil or coal. This means that a relatively small quantity of nuclear fuel can produce significant amounts of energy through fission. How does uranium compare to other fuels? Calculations vary a little, but through fission, 1 kg of enriched uranium corresponds to roughly 10,000 kg of mineral oil or 14,000 kg of coal. That’s a lot of raw material that can be left in the ground. //
A single nuclear fuel pellet in a typical reactor creates about the same amount of energy as one tonne of coal. //
nuclear energy stands its ground. It’s reliable and dependable, with the highest capacity factor of all energy sources, which means that power plants produce maximum power more than 92% of the time during the year. That’s almost twice as much as natural gas and coal and nearly three times more than wind and solar farms.
Since less raw material is needed to create the same amount of power, nuclear energy also has a very small land footprint compared to the alternatives. More land is required to mine the coal and dig the metals and minerals used in wind turbines and solar panels out of the ground, and for the sites they are built on, which makes it the most land-efficient source of energy. //
