Sunday, July 21, 2013

The physics of spent nuclear fuel: 1 hour LIVE presentation tomorrow on Google Hangouts by Ace Hoffman


Hi all,

Sorry for the late notice, but we're going to try to do a live "Google Hangouts" tomorrow (Monday) morning at 9:30 Pacific Time (12:30 EST) on "The Physics of Spent Nuclear Fuel." We'll record it for posting later, as well.

San Onofre has about 4 million pounds of nuclear waste on site. Some people want to just put it into dry casks right where it is and "forget about it" for a few generations.

But dry casks aren't safe! They're not strong enough, they're too close together, they're going to decay, degrade, and disassemble at the molecular level. They are vulnerable to earthquakes, tsunamis, terrorists, accidents, and poor fabrication or design. To name just a few problems that are possible.

To get the URL for the presentation please go to this URL tomorrow a few minutes prior to the presentation:


The actual hangout URL will be posted there tomorrow. Anyone can join (in listen-only mode).

Ace Hoffman
Carlsbad, CA

Saturday, July 13, 2013

A spent fuel accident at San Onofre Nuclear Waste Dump could cost a trillion dollars. Deal with it.

Some people would be happy to leave San Onofre's 1,400 tons of accumulated radioactive spent fuel, from nearly half a century of leaky, unreliable, expensive and disquieting operation, right where it is.

On an earthquake fault line, in a tsunami inundation zone, amongst 8.7 million of the most beautiful, industrious, peaceful and creative people in the world -- from all over the world -- who live within a 50 mile radius of the waste, and tens of millions more who live just slightly beyond that artificial marker.

The highly radioactive used reactor cores will be stored locally in relatively flimsy (for their purpose) containers called dry casks. These casks -- about 40 [51] are on site now, the oldest about 10 years old, with 100 or more yet to come to empty the spent fuel pools of fuel -- cannot resist significant forces of any sort (manmade, natural, you-name-it).

Indeed, the casks are not even DESIGNED to withstand forces such as earthquakes greater than 7.0 (i.e., "The Big One" is not covered), or submersion in greater than 50 feet of water (i.e., any reasonably large tsunami), or boats crashing into them during the tsunami, or large jet airplane strikes (accidental or purposeful). Why aren't they built to withstand these things?

Because they're considered temporary solutions to the waste problem. But these casks will sit here for decades, near major shipping lanes and under several commercial airline routes. The Nuclear Regulatory Commission optimistically suggests it might only be 60 years of storage but they plan for it to be several centuries. They might as well say it's forever.

During that time, however long it is, the spent fuel will not be secured against terrorist attacks with satchel charges or rocket-propelled grenades -- or depleted-uranium spears dropped from balloons, for that matter. These containments just aren't that good.

Rail accidents on the nearby tracks could cause massive explosions, as we've seen recently and horrifically in Canada.

San Onofre's dry casks have some lead, a couple of inches of steel, and three to five feet of concrete. The main purpose is for shielding of gamma rays and protection from water vapor in the air (the casks are filled with inert gases to prevent any air getting in).

For comparison, San Onofre's reactor pressure vessels (which still sit on site, and one of which is still loaded with fuel) have six to eight inches of steel, and then a 4 to 8 foot thick reinforced concrete dome enclosing that. But it is well-known that even those thick domes would not be sufficient protection against airplane strikes by large commercial or military aircraft. (There are, of course, many other hazards an operating reactor is vulnerable to, as well.)

And stacking the dry casks together as they are doing at SanO is also inappropriate. There needs to be more separation between each cask because in the event of an impact of any kind, they can all be pushed together and the cement crumbled, making a criticality event at least theoretically possible. If the impact is from a large jet, the burning jet fuel can ignite multiple casks.

The only reason the casks are packed so tight together is because SCE didn't lease much land for San Onofre in the first place -- they didn't expect to "need" to build dry casks. The local residents and local elected officials were promised the waste would be removed as soon as it had cooled sufficiently for transport -- about five years, they were told. San Onofre Nuclear Waste Dump is located on about 75 acres of coastal bluffs a few hundred feet west of an eight-lane freeway and a major railroad line. SoCal Edison also leases about 400 acres on the east side of the highway for administration, training, and so forth. They have a state-of-the-art reactor simulator there, which somehow failed to train them for what actually happened. (When the leak that closed San Onofre forever occurred on January 31, 2012, operators were completely baffled as to what had caused the tube degradation. Frankly, they still don't know. They were going to experiment with a 70% restart, but the citizens opposed such a plan so vehemently that on June 7, 2013, SCE gave up and announced they would decommission the plant.)

The entire San Onofre area is vulnerable to many natural and manmade hazards, but if the waste remains on site, any such disaster could also burden society with the additional problems of widespread radiation exposure, which would be much more devastating, for an immeasurably longer period of time.

Nevertheless, some people, even some among those who helped shut down San Onofre because of the danger, now refuse to talk about moving the waste, primarily for one of two reasons:

First, they are concerned about transportation accidents -- a reasonable fear.

But consider this: Transport risks last for only a few days each trip, and there are a finite number of trips, because, thankfully, the reactors at San Onofre are permanently closed. So that's a relatively limited risk. On the other hand, leaving the waste to sit dangerously in an earthquake/tsunami/growing population zone is a danger that lasts for decades or centuries, and possibly forever.

The other reason some people oppose transporting the waste away from San Onofre is that there's nowhere to put it.

That is also a reasonable concern. Citizens, once alerted to the dangers spent fuel represents, invariably wise up and oppose both the transport of waste through their communities, and especially, becoming the "final destination" which will, inevitably, be called a temporary location.

But for all intents and purposes it will be permanent, because we are all waiting for the impossible: A better solution to the nuclear waste problem than either of our actual available two choices: Storing it, or releasing it into the environment. There are no other choices. About 97% of the spent fuel waste has no value whatsoever, but is radioactive, so it has lots of "negative value." The rest -- plutonium and uranium of the "right" isotopes -- only has value for making more nuclear power plants and nuclear bombs. In other words, it, too, has no real value. (Nuclear medicine has never used more than a relatively minuscule amount of a few short-lived isotopes for diagnostic purposes.)

Nuclear waste is a tremendous liability to society. It always has been, and it always will be.

All plans for long-term or "interim" storage have been stopped thus far -- not by "NIMBYism" so much as by common sense. No sane community wants the waste. 50 years ago the waste issue was recognized by many top scientists -- brilliant nuclear physicists -- as "intractable." The definition of "intractable" has not changed in the interim. Solutions have not been found.

Shutting down all the reactors is the critical first step, since a closed reactor is no longer making MORE waste. However, at San Onofre, where that first step has recently been taken, some people refuse to even discuss removing the waste and instead, support the utility's plan for permanent on-site dry casks, pausing only to demand that those plans be implemented as quickly as possible, without considering any other alternatives.

Frankly, SoCalEdison couldn't care less what we do with our waste.

SCE is already authorized to walk away from the problem, maintaining just a few guards at ratepayer expense for eternity. SCE is also insured, and to top it off, their insurance is capped by federal policy at fractions of a penny on the dollar if anything goes wrong. So they have no reason to care.

But dry casks -- especially the dry casks planned and currently used at San Onofre -- are inadequate. Fuel assemblies and even the fuel itself deteriorate over time from the heat and especially from the radiation. "High burn up" fuel, which San Onofre used for the last ten years, degrades its cladding especially quickly, making it much more fragile. This will significantly increase the risk if anyone tries to transport it later. As it deteriorates, high burn up fuel will also cause increased releases into the environment of radioactive noble gases and other radioactive isotopes including cesium, strontium and plutonium.

Greater protection is theoretically possible -- but it's more expensive, and it requires moving the waste to a safer location that hasn't been found yet. However, that doesn't mean it shouldn't be done or can't be done. It just means it hasn't been done. New dry casks are popping up around the country at the rate of about one a week these days. As spent fuel pools fill up, that rate will increase to a steady-state (for 100 reactors) of about 4 to 6 dry casks per week around the nation.

Each one, if its contents get out, could wipe out a small state.

There are a total of about 75 sites in America with operating or closed nuclear reactors. Almost all have spent fuel stored on site. Most are under various airline routes. All are vulnerable to terrorism. San Onofre has repeatedly been cited as a likely terrorist target by elected officials because of the devastating damage an attack could do to the economy and lives of so many millions of people. Have the lessons of 9-11 truly been forgotten just 12 years later?

The time to solve the nuclear waste problem is now, not later. Once the waste has "cooled" enough to remove it from the pools, it is still incredibly hot (as much as 400 degrees Fahrenheit at the fuel rod's surfaces) and stays hot for many years. The heat is produced mainly by the decay of fission products, emitting deadly gamma rays (hence the lead, steel, and cement shielding) as well as alpha and beta particles.

The spent nuclear fuel is in danger of fire by several methods, including, of all things, water intrusion, which can lead to zirconium cladding degradation along with splitting the water molecules into separate hydrogen and oxygen atoms. This chemical reaction created an explosive atmosphere three times at Fukushima, and is known to have happened in at least one dry cask here in the states -- but it was discovered before an explosion occurred. Will we always be so lucky?

As the fission products decay, the spent fuel cools and becomes "safer." However, it doesn't become "safe" ever. Many of the most dangerous isotopes, such as cesium and strontium, have half-lives in the 30 year range, and are at their peak now. Thus, the importance of taking care of the "spent fuel problem" is highest now -- much higher than, say, 30 years from now when about half the cesium and strontium will have decayed. So waiting makes no sense. The waste's most virulent components are at their peak quantities right now, and an accident now would be the most devastating for the planet's collective DNA -- DNA which has already taken a terrible hit from weapons testing and use, from Chernobyl, from Fukushima, from 1000 other accidents and purposeful spills, and from continuing leaks at Hanford and other nuclear sites.

There is really only one logical conclusion, of course: It's time to shutdown the reactors everywhere. In China, Russia, France, England, India, South Korea, and everywhere else, not just in southern California. Currently nuclear waste is stored in at least four locations in California. Those four sites need to be consolidated into one highly protected site, with earthen berms between EACH cask, and a "no-fly" zone and other considerations.

But how will consolidation be accomplished when communities are bullied into supporting flimsy, inadequate dry cask storage wherever the waste was produced, regardless of the danger?

Activists in Humboldt County and around Rancho Seco have accepted dry cask storage for years. Why shouldn't southern California?

The answer is, because southern Californians understand, post-Fukushima, what the real dangers of spent fuel are. For all intents and purposes Fukushima was a spent fuel accident. While it's true that the reactors tripped after the earthquake and had only been shut off for a short while when the tsunami struck, it's also true that even if the reactors had been off for years, the same basic sequence of events could have happened if water wasn't circulated properly around the used fuel assemblies.

Spent fuel is incredibly deadly stuff, but in fact, Fukushima was not a "worst case scenario" by any means. An even larger catastrophe is still possible at Fukushima because of the fuel that's still there in the spent fuel pools and dry casks, and because the melted blobs of "corium" (uranium and plutonium) can theoretically go critical again. Massive explosions of the corium blobs are also possible without a new criticality event, when/if they reach the local water table. And more than two years after the meltdowns, nobody knows precisely where the corium blobs are.

There are 23 reactors similar to Fukushima's operating in America, and all other types of reactors have other dangers which make them just as capable of catastrophic accidents as those were, but in different ways. There are no "safe" reactors, and there is no safe way to store or transport the fuel.

If America chooses not to wake up to this reality, sooner or later it will cost us dearly: A spent fuel accident at San Onofre Nuclear Waste Dump could cost a trillion dollars. The spent fuel will need to be guarded for hundreds of millennia, but right now it is MOST important that it be guarded properly.

Whatever the "interim" storage solution is -- wherever it is -- needs to be thought of as "permanent" since it will inevitably be expected to last for hundreds of years. The current, totally ludicrous plan is that, while the fuel is the most dangerous by several orders of magnitude, we plan to store it in the cheapest "temporary" containment system of all. Then we plan to transport it after its fuel cladding and structures have all degraded and are far more likely to cause problems and radiation releases during shipment. THEN we plan to finally move it!

Our current national nuclear spent fuel policy will inevitably result in catastrophic dry cask accidents somewhere -- perhaps near large population centers.

Shutting down ALL the reactors now, and properly securing ALL the waste immediately, is the only logical thing to do.

Ace Hoffman
Carlsbad, CA

The author, an independent investigator, has been studying the problems of nuclear power for many decades. His 2008 handbook of nuclear facts, called The Code Killers, is available for free download here:


Wednesday, July 3, 2013

What Fukushima's failures might have taught the terrorists...

The storage system for highly radioactive used reactor cores at San Onofre is not "hardened" against anything significant. There are no active air defenses around it of any sort. Many people bandy the term "hardened" around -- using it five times in one report, for instance. But there is no legal or industry standard definition of "hardened" nuclear waste storage and if there were, San Onofre surely would not qualify.

What some people are calling "hardened" is merely the necessary gamma shielding made of lead and steel a couple of inches thick, surrounded by a cement overpack that is three to five feet thick. They are NOT referring to spent fuel storage systems that can endure real-world conditions such as impacts from the turbine shafts of jumbo jet airplanes during accidental crashes or terrorist strikes, followed by the pooling and burning of 35,000 pounds of jet fuel. San Onofre's dry cask storage farm is directly under several major airline traffic routes, so either an accident or a hijacking could cause an impact.

Nor are they referring to casks that can survive impacts from molten-metal penetrator bombs or carefully-placed shaped charges.

Truly "hardened" dry cask storage would include, at the very least, grade-level or underground enclosures for each cask, with 20-foot-thick reinforced concrete roofs. The steel alone would cost billions -- and be money well-spent. There would be earthen berms between EACH cask, and jet-fuel run-off channels. And don't do this in an earthquake or tsunami-prone zone. And not near where people or animals are, or will ever be, although there is always a force which might strike at any moment and which can overcome anything humans might build: Locations under asteroid impact zones -- and who knows where that might be -- or on top of sudden volcanoes, or actually straddling an earthquake fault line, and probably a few others no one's thought of... Unlikely? Yes. Impossible? Far from it.

What we have now is just shielding from gamma rays. To be truly "hardened" against realistic potential events, you need much, much more. And you need to find a way to pay for it.

Forcing nuclear waste producers -- the electric utilities -- to create properly "hardened" storage -- on site or elsewhere --is too expensive to be part of an ongoing, profit-motivated nuclear fuel cycle. Most of them would have to constantly be purchasing more land. San Onofre hasn't got the space, that's for sure.

But where does one put a "properly" hardened dry cask system? The only way to know the true size and cost would be to shut down ALL the reactors and stop making more "spent fuel." Then, at least the problem would be of a finite (though huge) size. At that point it might be possible to think logically about what to do with ALL the nuclear waste in the country and on the planet -- once and for all. It won't be cheap and it won't be easy.

As a nation, we have done nothing about the growing problem of nuclear waste for 65+ years. Other nations do a variety of things -- wrong things. America's managed not to make THAT mistake -- and instead, has done as little as possible. Some nations are following our lead and are storing nuclear waste dangerously on site where it is made, regardless of the growing risk to the local population and to the planet.

As so many have said before me, part of finding a solution requires realizing that no solution will be perfect. But it's time to solve the nuclear waste problem for real: Quickly and globally. I know of only one sure-fire step that must be taken: Shut down ALL nuclear reactors: Their risks and costs don't justify their existence. ("Oh!" -- cry the pro-nukers -- "What about medical isotopes?!?" For medical requirements, two dedicated systems -- one on either side of the globe -- would suffice, and they would not produce nearly as much nuclear waste as a power reactor which only produces medical isotopes as a side business. Also, many medical procedures which use radioactive isotopes are being replaced with more benign methods, such as ultrasound and MRIs.)

Waiting to solve the nuclear waste problem at some future date is potentially disastrous. The time for the best, strongest, most robust solution is now, when the waste is by far the most toxic it will ever be. We'll still need proper containments for today's spent fuel waste for hundreds of thousands of years, but even just a few centuries from now the overall radioactivity will be several orders of magnitude less than it is today. Many long-lived isotopes would still remain, but the short-lived fission products -- the dominant radioactive isotopes for the first few hundred years -- would exist at a fraction of 1% of their current levels. If those "short-lived" isotopes get out, a lot of permanent damage could be done to the gene pools of every organism on earth including humans. So early protection is vital: Robust, "hardened" storage in depopulated areas. And an absolute stop to the continued operation of these uneconomic, accident-prone death-machines known as nuclear power plants.

In a free market, nuclear power would have died for financial reasons by now. But that's not happening fast enough, since various regulatory agencies keep the plants profitable for their owners. But every day the world continues to use nuclear power, the size of the problem the industry leaves behind increases by about 10 tons nationally and 50 tons globally. That's a significant amount, because spent fuel is so difficult, expensive and risky to manage. The spent fuel dilemma is a massive, hidden global problem. It's time to define "hardened" storage properly, in terms that fit the geological as well as the geopolitical realities of today.

When it was announced on June 7th, 2013 that the San Onofre Nuclear "Waste" Generating Station (known as "SONGS" because the waste (W) was ignored) would remain closed permanently (after being shut down since January 31st, 2012), it instantly went from having been a "nuclear power plant" to being one of the largest nuclear waste dumps in America, in terms of the quantity of lethal poisons within its space. It continues to be one of the most vulnerable targets for terrorists in all the world.

An article in today's Japan Times (below, from Bloomberg news service) says that Fukushima "may provide a blueprint for terrorists" for attacks on operating reactors -- since "all you need to do... is to cut off the power."

It's not quite that simple: At Fukushima a contributing factor was that the entire area was in turmoil from the earthquake and tsunami. But if Japan should be worried about terrorism at nuclear facilities, doesn't it make sense that we should be, too? Of course it does.

But in fact, anyone who knew anything about nuclear reactors -- which surely included the terrorists -- has known all along that cutting off the power to a nuclear facility could cause a meltdown. That's why for decades, activists have been trying to demand more robust backup power systems for nuclear facilities! Such enhancements were always deemed "too expensive" but in light of Fukushima, it clearly would have been worth it to spend the money.

What Fukushima might have taught the terrorists is that it's the radiation that causes the financial and health problems. Destroying an operating reactor is one way to cause a radiation release, but attacking spent fuel pools or dry casks can work equally well for the purpose of causing widespread contamination and ensuing havoc, panic, and destruction.

And lest we forget, neither Fukushima nor even Chernobyl were anywhere near a "worst case scenario" for those types of reactors. The majority of the plutonium and uranium remains -- in seething blobs known as "corium." One formation of corium at Chernobyl even has a name: The Elephant's Foot. It's crumbling. At Fukushima three reactors have turned to "corium." The corium blobs ooze massive quantities of radioactive particles constantly, and will continue to do so for decades millennia.  And at both Fukushima and Chernobyl, things can still get far worse, and there's nothing anyone can do if that starts happening.

Meanwhile, their precarious spent fuel pools remain loaded with fuel, 60 feet above ground level in earthquake-damaged, tsunami-damaged, and explosion-damaged buildings. All the spent fuel anywhere near the melted-down reactors should be removed from the sites immediately.

But at any site, and at San Onofre in particular, terrorists or Mother Nature can damage a spent fuel pool or a dry cask farm, even if damaging an operating nuclear reactor is theoretically easier.

A dry cask storage farm might have a couple of rent-a-cop security guards overseeing it, who are expected to "call for backup" if anything goes wrong -- assuming the phone systems are working. They are not expected to be able to fend off any significant attack by themselves.

An operating reactor has nearly a thousand people working on site, and all of them are (supposedly) trained to be watching for "anything suspicious." There can be double that number of people or more, if it's a multi-reactor facility.

So which is easier to attack? Spent fuel nuclear sites can release massive quantities of radioactive poisons, although an operating reactor will also release a lot of very short-lived components with half-lives in the 8-day range or even less. These short-lived radioactive elements will certainly cause additional panic and suffering among the local populace, but it's the 30-year half-life components such as strontium and cesium, and the 25,000-year half-life plutonium, which will cause long-term or permanent population displacements and loss of manufacturing, agricultural, and natural resources. These extremely dangerous isotopes are all stored in copious quantities in dry casks. (As a rule-of-thumb, radioactive materials are considered dangerous for 10 to 20 half-lives.)

While moving the waste several times is risky and should be avoided, waiting to move the waste to truly hardened, monitored storage, away from population centers, is even more pure folly: It is a gamble which could result in the catastrophic and sudden loss of tens of thousands of lives and trillions of dollars.

For nothing.

Ace Hoffman
Carlsbad, CA

Fukushima a 'blueprint' for terrorists, IAEA warns:


Nuclear meltdown a recipe for mass disruption, security experts say

Fukushima a 'blueprint' for terrorists, IAEA warns
JUL 3, 2013

VIENNA ­ The Fukushima No. 1 nuclear plant, whose 2011 triple-meltdown forced the relocation of 160,000 people, may provide a new blueprint for terrorists seeking to inflict mass disruption, security analysts said Monday at a meeting of the International Atomic Energy Agency.

The U.N. atomic agency convened a weeklong meeting of 1,300 diplomats, scientists and security analysts in Vienna to examine ways to boost protection against nuclear terrorism. The meeting is the IAEA's first ministerial conference.

"Fukushima sent a message to terrorists that if you manage to cause a nuclear power plant to melt down, that really causes major panic and disruption in a society," Matthew Bunn, a Harvard University professor and former White House adviser, said at a briefing. "All you need to do to do that is cut off the power for an extended period of time."

Leaders across the globe have pledged to secure the world's loose nuclear material by 2014 to reduce the likelihood of an atomic attack by terrorists. While national nuclear facilities primarily endeavor to track the vast quantities of unaccounted for uranium and plutonium, some focus has shifted to the threat posed by power plants.

Fukushima "has provided a number of findings and lessons that are also useful for preparations for an incident caused by human hand, such as a terrorist attack at a nuclear power station," said Shunichi Suzuki, Japan's envoy to the meeting.

Japan's Atomic Energy Agency was scheduled to present steps it's taken to boost security against terrorism Tuesday in Vienna. The IAEA conference is taking place behind closed doors.

"Fukushima is a nuclear security problem as much as it was a nuclear safety problem," said Kenneth Luongo, who with the U.S. Department of Energy helped secure atomic material in Russia after the collapse of the Soviet Union.

The IAEA has projected nuclear power is set to expand worldwide even after the March 11, 2011, earthquake and tsunami sparked the triple-meltdown and radiation leaks at Tokyo Electric Power Co.'s Fukushima No. 1 plant.

A nuclear-armed terrorist attack on the port in San Jose, California, would kill 60,000 people and cost as much as $1 trillion in damage and cleanup, according to a 2006 Rand Corp. study commissioned by the U.S. Department of Homeland Security.

Even a low-level radiological or dirty-bomb attack on Washington, while causing a limited number of deaths, would lead to damages of $100 billion, according to Igor Khripunov, the former Soviet arms-control envoy to the U.S., who's now at the Athens, Georgia-based Center for International Trade and Security.

Because a terrorist needs only about 25 kg of highly enriched uranium or 8 kg of plutonium to improvise a bomb, the margin of error for material accounting is small. There are at least 2 million kg of stockpiled weapons-grade nuclear material left over from decommissioned bombs and atomic-fuel plants, according to the most recent estimates by the International Panel on Fissile Materials, a nonprofit Princeton, New Jersey, research institute that tracks nuclear material.

That's enough to make at least 100,000 new nuclear weapons on top of the 20,000 bombs already in state stockpiles.



Comment left at Japan Times about the above article "Redlotusglenn":

Article says:
"Fukushima sent a message to terrorists that if you manage to cause a
nuclear power plant to melt down, that really causes major panic and
disruption in a society,"

You don't say.

And I'm pretty sure it didn't just send that message to terrorists. The entire population of Honshu North of Tokyo has probably also caught on.

The nuclear industry has managed to do all that without the aid of any terrorists - stop obscuring the issue. Nuclear power stations on a tectonically active set of fault lines don't need any terrorism to go wrong. They just need time. It's a geological certainty.

Conversations on nuke waste storage:

Barbara George: "I'm aware that casks survived Fuku.
But will that always be so?

Michael Welch: Why wouldn't it be. Not understanding the question.

Michael, there are far too many variables to predict with any degree of certainty that dry casks currently housing spent fuel assemblies at SanO and Diablo would perform as well as the Fukushima casks should a big quake or tsunami hit in years to come. For one thing the large inventory of spent high burn-up fuel assemblies at SanO have cladding vulnerabilities yet to be fully understood - scientists suspect that as the assemblies age the cladding becomes increasingly brittle and problematic.

For more info check out this Sept. 2011 analysis from DoE's Argonne Lab (ADVANCED SURVEILLANCE TECHNOLOGIES FOR USED FUEL


Residual activity (from Bennett Ramberg):

Contact information for the author of this newsletter:


Ace Hoffman
Author, The Code Killers:
An Expose of the Nuclear Industry
Free download:
Carlsbad, CA
Email: ace [at]