Deep Borehole Nuclear Waste Disposal

There will always be NIMBY's with just enough knowledge to be dangerous who do not understand the concepts of risk management. If you cannot guarantee an infinite number of 'nines', they will march around with their signs once CNN shows up with their cameras. A little ignorance goes a long way.

Would you rather have above ground storage? ....because this is the only other option...

The waste is already in your backyard...

I was speaking to the potential NIMBY's...not BSR per se....

Nope, not me. Not sure why they haven't proceeded with Yucca Mountain. I always thought that Yucca Mountain was more than adequate.

..."The Yucca Mountain Nuclear Waste Repository, as designated by the Nuclear Waste Policy Act amendments of 1987, is to be a deep geological repository storage facility within Yucca Mountain for spent nuclear fuel and other high-level radioactive waste in the United States. The site is located on federal land adjacent to the Nevada Test Site in Nye County, Nevada, about 80 mi (130 km) northwest of the Las Vegas Valley.

The project was approved in 2002 by the 107th United States Congress, but federal funding for the site ended in 2011 under the Obama Administration via amendment to the Department of Defense and Full-Year Continuing Appropriations Act, passed on April 14, 2011 by the Republican controlled house of Representatives.^[2] The project has encountered many difficulties and was highly contested by the non-local public, the Western Shoshone peoples, and many politicians.^[3] The project also faces strong state and regional opposition.^[4] The Government Accountability Office stated that the closure was for political, not technical or safety reasons.^[5]

This leaves American utilities and the United States government, which currently disposes of its transuranic waste 2,150 feet (660 m) below the surface at the Waste Isolation Pilot Plant in New Mexico,^[6] without any designated long-term storage site for the high-level radioactive waste stored on site at various nuclear facilities around the country.

Under President Barack Obama the Department of Energy (DOE) was reviewing options other than Yucca Mountain for a high-level waste repository. The Blue Ribbon Commission on America's Nuclear Future, established by the Secretary of Energy, released its final report in January 2012. It detailed an urgent need to find a site suitable for constructing a consolidated, geological repository, stating that any future facility should be developed by a new independent organization with direct access to the Nuclear Waste Fund, which is not subject to political and financial control as the Cabinet-level Department of Energy is.^[7]

Under President Donald Trump, the DOE has ceased deep borehole^[8] and other non–Yucca Mountain waste disposition research activities. For FY18, the DOE had requested $120 million and the NRC $30 million^[9] from Congress to continue licensing activities for the Yucca Mountain Repository. For FY19, the DOE has again requested $120 million but the NRC has increased its request to $47.7 million.^[10] Congress decided to provide no funding for the remainder of FY18.^[11]

In the meantime, most nuclear power plants in the United States have resorted to the indefinite on-site dry cask storage of waste in steel and concrete casks.^[12] "...

https://en.wikipedia.org/wiki/Yucca_Mountain_nuclear_waste_repository

"

US budget request supports Yucca Mountain

12 March 2019

http://world-nuclear-news.org/Articles/US-budget-request-supports-Yucca-Mountain

I have always thought that a solid canister and a rail gun to the sun would be ideal.

That might make a good Wile E Coyote cartoon, but has no basis in reality...

I agree, but cost prohibitive

A) Trying to hit the sun is a lot harder than it looks. Miss by just a little and you've put the payload into a long, elliptical orbit that crosses the orbits of many planets. Better hope it hits someone else, not us.

B) Sending ANYTHING into space carries the risk of the container exploding/rupturing in flight and scattering the payload across a significant portion of the planet. Do YOU want to live downrange of that gun, and how many times around the planet would that 'downrange' wrap if it ruptured at, say, the 'edge of space'?

All very good questions and I am certain there are engineers out there who can solve them given enough time and money. Aren't they always the two limiting factors in our decision process?

There could be something in favor of above-ground storage: Continued access if anything goes wrong.

I don't know if the Yucca Mountain scheme includes that possibility. It seems that some of the "NIMBY" opposition is coming from outsiders not in the BY to start with. However, for those who are in the BY, what gives anyone else the right to bury their garbage there? (Sure, we can think of such things as eminent domain.)

As for the borehole idea, how would one get canisters to move down, around the curve, and then into what appears to be an expanded upward section where they could just jam up?

Something was said about "no transportation." Huh? The closest shale formations shown were over a hundred miles from Hanford, which is a large source of accumulated nuclear waste, about 15 miles from where I live.

Both the Yucca mountain and borehole disposal sites are monitored continuously and the storage canisters can also be retrieved if there is any reason, whether for replacing damaged canisters or repossessing of some kind...The storage sites are not abandoned...The Yucca mountain site was chosen after several years of research into the safest location possible...If we are to have these storage sites I think everyone can agree we want the safest location possible, and it was voted to be that by congress after much research and expert testimony over the years....The Yucca mountain storage site is not opposed by locals, so there is no NIMBY involved...just money and jobs, the locals voted on this as well...This was and is a multi-billion dollar project in the middle of nowhere...and yes there is of course some minimal transportation, but it pales in comparison to shipping waste from all over the country to Yucca Mountain....which frankly I don't have a problem with in the first place...I mean it is sealed in very robust containers...I was thinking more of the cost...

Thanks for the extra info on Yucca Mountain; I had thought so but wasn't sure that access was maintained.

I agree that lesser transportation is desirable, but the article said no transportation. Hyperbolic claims like that make me suspicious.

Along with you, I am not overly scared about any of this. The vitrification of Hanford waste will supposedly cost US$ 300B, with possible overruns up to 3x of that. To me that reeks of boondoggle. I haven't researched that aspect much, but I have some friends working on the vit plant project who might be able to tell about it.

https://www.hanfordvitplant.com/

https://www.exchangemonitor.com/long-form-stories/the-hanford-waste-treatment-plant-a-21st-century-solution-to-a-70-year-old-problem/

Yes, there were many dollars spent on research and development of shipment carriers for the nuclear waste that involved simulated crashes of train cars or whatever to come up with shipment containers to prove that they were more than just robust.

"It seems that some of the "NIMBY" opposition is coming from outsiders not in the BY to start with."

That particular opposition is more a "Don't Ship It On The Tracks By My House" complaint.

And while the DSIOTTBMH crowd do have a point, since the odds of a freight train accident at any given point on the route is, by definition, non-zero. The odds CAN be minimized through strategic planning: moving the "nuclear torpedoes" by Slow Freight or, even better, a "Private Charter" train, where the spent fuel (and the obligatory "spacer" cars) are the only cargo. Security along the route can also be increased during the shipment, to prevent any accidents or sabotage. Choosing a route that avoids major cities, and only passes through towns when they are effectively deserted, or the towns can be evacuated for the hour the train is passing through.

The solution is easy, only takes time and money.

BSR: Agreed. They seem to understand, or at least sincerely pass on, the rumors and mis-information, but refuse to accept actual information. As someone else has said: "fake news."

There are only 2 choices for hazardous waste disposal that I know of, burn it or bury it...This is true throughout the world...You are implying there is another way that is preferable, what would that be?

https://www.epa.gov/uic/class-i-industrial-and-municipal-waste-disposal-wells

The deeper it goes, the smaller the footprint of the <...within borders...> becomes.

This is a responsible long term solution...it's a good thing...as opposed to the past when waste was of little to no concern....It should be embraced...

..."Due to historic activities typically related to radium industry, uranium mining, and military programs, numerous sites contain or are contaminated with radioactivity. In the United States alone, the Department of Energy states there are "millions of gallons of radioactive waste" as well as "thousands of tons of spent nuclear fuel and material" and also "huge quantities of contaminated soil and water."^[19] Despite copious quantities of waste, the DOE has stated a goal of cleaning all presently contaminated sites successfully by 2025.^[19] The Fernald, Ohio site for example had "31 million pounds of uranium product", "2.5 billion pounds of waste", "2.75 million cubic yards of contaminated soil and debris", and a "223 acre portion of the underlying Great Miami Aquifer had uranium levels above drinking standards."^[19] The United States has at least 108 sites designated as areas that are contaminated and unusable, sometimes many thousands of acres.^[19][20] DOE wishes to clean or mitigate many or all by 2025, using the recently developed method of geomelting,^{[citation needed]} however the task can be difficult and it acknowledges that some may never be completely remediated. In just one of these 108 larger designations, Oak Ridge National Laboratory, there were for example at least "167 known contaminant release sites" in one of the three subdivisions of the 37,000-acre (150 km²) site.^[19] Some of the U.S. sites were smaller in nature, however, cleanup issues were simpler to address, and DOE has successfully completed cleanup, or at least closure, of several sites.^[19] "...

There are many sources of radioactive waste, nuclear energy is just one...We are working to clean it up, complaining about it or blocking it, serves no purpose other than to delay the process...

https://en.wikipedia.org/wiki/Radioactive_waste

Ah ha...Australia - an idea.
Australia has some very deep lead mines that have ended their lives, for example the Zinc Corp mine that is about 1km beep in a very stable, non-geoactive, hard rock area.
Mining never extracts 100% and in the case of the Zinc old upper worked stopes were back filled with skimps (process waste - essentially washed fines still with an ore percentage) so in other words a think lead blanket.
Why not take the waste down the bottom of mines like this and "dissolve" the waste, and then leave the wastes waste down there in concrete (or plastic bag waste).
The waste exists and will continue to grow because of the need of the product it comes from.
Will it cost...yep...so be it, but it is about finding a solution - it shouldn't be solely about money.

Australia has been investigating for some years that as the source of much of the Uranium there is some (shared) responsibility with the users to develop storage for the waste.

Some are suggesting return to the original mining sites, while others seem more focused on remote locations.

The concept being that the waste is stored here but still "owned" by the intermediate user who could retrieve their "canisters" if some future beneficial use was identified for the contents. Storage as a "fee for service" process.

The problems really arise when the companies no longer exist, but the waste material persists. Whether buried or above ground, there should be incentives always to minimise the amount.

Remember that fast neutron reactors, Generation IV, have less waste by a factor of about 100, and the difference is used for energy--meaning that we get about 100 times more energy from it. It can utilize the "waste" now in storage. We have enough uranium isotopes, thorium, etc in storage, that none will have to be mined for a very long time.

Thanks for the feedback.

While I anticipate there will be "resource recovery" processes applied to the spent fuel elements, I understand that the vast bulk of the "waste" is actually facility hardware that through it's intended use now is contaminated and need to be stored, maybe with lower half-life than the fuel elements.

There is another waste steam that is not necessarily being discussed and that is the depleted uranium from the ore refining process. The "heavy" nature of this was used for ballistic projectiles, but now probably is "off the table" due to observed side effect from its use. That stuff would probably be ideal candidate for "return to source" (mine site) for longer term storage along with the lower concentration ore body. Not saying to scatter it back at the site, just stored as ingots.

Depleted uranium, U-238, is not "waste," but becomes fuel for the fast reactor. By adsorbtion of a neutron it transmutes to Pu-239 which is fissile. Thus it is a fuel in a fast reactor. There is enough U-238 on hand, left after enrichment of natural uranium, that we will not have to mine it for a very long time.

There is no such place as "away". There is only nearer or farther from here.

Reduce, reuse, recycle. In that order. But don't let the difficulty of waste management stop the use of nuclear power. Waste management is part of the cost that is sometimes ignored.

If containers deteriorate then some material may move to low point (a natural process), then break down (natural radioactive decay) into radon and travel upward. Contrary to "They would have to move down first, then up, something that cannot occur by natural processes.". Not significant because there is probably more radon being created in the other 4,000 miles of earth below it but statement (in quotes) is not completely true.

Why not reprocess? It's legal since 1986 and about 97% of the spent fuel goes back into the fuel cycle. We have facilities capable of reprocessing here, but if we won't do it, set up the mechanism to transfer it to the British, French or Japanese who will reprocess and potentially send back useable fuel.

Indeed we had the plant nearly completed for turning plutonium into fuel and the construction was halted....how much money was wasted here by lack of commitment and government indecision?

http://world-nuclear-news.org/Articles/NRC-terminates-US-MOX-plant-authorisation

Sounds good, but how do you get a drill to curve at the proper depth and then go upward? What keeps the bits from breaking?

Drilling equipment is actually steerable with the right setup. That's what the slant drilling issue in the Mideast was all about. Yemeni oil firms were drilling on a slant and then turning level to cross into oil fields in Iraq. My cable and power companies do the same when they are replacing lines. The drill goes in on a slant. is turned horizontal for a distance and then is turned up again for access from the other end.

https://en.wikipedia.org/wiki/Rotary_steerable_system

Directional drilling has been around for years.
Had a beer with a k1w1 friend last evening, who has just retired after 40+ years on the oil rigs (retired as an OIM for TransOcean), and he said that the hole as mentioned in SolarEagles' originating post is pretty straight forward and in the oil and gas fields has been done heaps of times before, including by him. Even though an OIM, as the title implies is an Off-shore Installation Manager, he has worked in Libya, Kazakhstan, among others on dry land...same deal but maybe somewhat simpler.
The hole would appear to be the least of the problems.

My concern is that if it is made too "easy" to dump the material, then there is no incentive to minimise the amount that this generation is leaving as a legacy for the future.

Exactly why I would like to have us head toward the fast neutron nuclear reactor (instead of the thermal neutron reactor mostly used now.) The waste volume is about 100 times less, and the difference is used as fuel for making energy. The radioactivity is less, as well as the time it must be stored.

But it is great to have available an alternate "disposal" method. But if we reprocess the thermal reactor "waste" (used fuel) into fuel for a fast reactor, we can get around 100 times more energy with the additional benefit of less waste that is far less redioactive.

Drilling horizontally, or even upward, is easy using today's oil well drilling technology.

I live in West Texas and we have nuclear waste disposal sites fairly close by. No problem, but the fear mongers are always trying to cause problems. We recently had a big brouhaha about transporting the casks by train. Some people thought that this stuff would actually 'leak' like a liquid.

I think that the ideal method of disposal is burial at sea, such as in the Mariana Trench (36,000 feet deep). This stuff has a high molecular weight, it's not going to float even if the cask ruptures.

As one that handled RA material every day while working in the oil industry, I'm certainly not afraid of it. People need to be educated about it. There was a time when people were afraid of electricity. Education is the key, but we don't teach actual science in public schools anymore.

We need to dismiss dirty technologies like solar, wind, hydroelectric, etc and embrace clean technologies like nuclear,,,So what if there's a little waste that is dangerous, toxic and poisonous for millions of years,,,we can always bury it down some hidey hole,,,out of sight, out of mind.

I think the OT'ers missed the sarcasm emoticon.

BSR, you/we/I only stay ot in this post if you support or agree with their agenda. They must have their financial portfolio's wrapped up in nuclear weapons, power plants, disposal etc. What could possibly be the incentive to push an energy source that while in operation is haphazard at best, yet produces a waste that is deadly at worst.

Sure, there is a need for nuclear products, albeit a minor one. For over 65 + years it has been promised and promoted that there would be a clean energy solution, that has never materialized, nor will it ever.

Continuing developments in cleaner alternative energy and fuels will eventually become the death knell of this industry.

Still, there are the holdouts, clinging to empty promises and their echoes, yet in their eyes, anything that offers a glimmer of hope is worthy of extolling praise.

Imagine the landscape dotted here and there with millions of subterranean disposal sites, all part of a lasting legacy of the stupidity of man.

..."The Earth itself is a source of terrestrial radiation. Radioactive materials (including uranium, thorium, and radium) exist naturally in soil and rock. Essentially all air contains radon , which is responsible for most of the dose that Americans receive each year from natural background sources."...

..."The numerous sources of nuclear waste include medical waste, industrial waste, and tailings from naturally occurring radioactive materials in metallic ores, coal, oil, and gas."...

Your worst fears have already been realized....

https://www.sciencedirect.com/topics/earth-and-planetary-sciences/naturally-occurring-radioactive-material

SE, see post #31

tony see #33...

There are certainly a lot of problems with solar, wind, hydroelectric, etc. For instance, solar and wind are not available on demand. Kind of a bummer when you're on the operating table and the wind stops blowing. Both take huge amounts of land. Solar requires that the panels be kept clean to operate efficiently, and a hail storm would wreak havoc on them. Wind generators only develop rated power when the wind is about 30 knots. Cut the wind velocity in half and the output drops by a factor of 8. They don't work in calm wind, they can't operate in high winds, and they can't operate in snow and ice.

Hydroelectric dams? Most dangerous form of energy ever devised. More people have been killed as a result of ruptured dams than any other form of electric power. And, they also take up a lot of real estate. AND, you'll have the environmentalist wackos breathing down your neck about disrupting fish, snails, snakes, etc.

Nuclear? Hmmm... It doesn't take up much space. It doesn't make any noise. It doesn't smell bad. In fact, you wouldn't even know that you were near a nuclear plant if you couldn't see it. Oh, let's see. How many people have been killed by nuclear accidents in the U.S. in the last 50 years??? Name one, if you can.

The post didn't mention anything about nuclear accidents. You did read the post, didn't you,,,

Yes but the fact remains Nuclear has the best safety record, doesn't trash the natural landscape and destroy wildlife habitats, has a longer potential lifetime of service by multiples, and most importantly, is available 24/7...When your wind turbines and solar panels reach end of service life, they will be landfilled...they have no end-of-life strategy...

Exactly, only nuclear has a " End of life " strategy.

I think all energy sources have had deaths resulting from getting this energy. Nuclear energy has NOT.

Wrong. Fukushima, for instance. Here is an even-handed article with some details:

https://www.energycentral.com/c/ec/deaths-nuclear-energy-compared-other-causes

Despite this and a fairly small number of other cases, nuclear seems to be the safest energy production method to date. But the number of casualties is not zero. Your exaggerated propaganda only diminishes your credibility.

Fukushima is not in the US....neither is Chernobyl...We have no control over what happens in other countries as far as planning and engineering...If you were building a nuclear power plant on a coastline that was prone to tidal waves and earthquakes, would you locate the backup generators in the basement? If you ask me nobody in their right mind would, and how this happened is a mystery to me...In any case these are older designs that date back many years, the newer designs we're talking about are walk away safe....The only real danger from a nuclear reactor is exposing the core, if you make that impossible, the system is inherently safe...Which means that not only is nuclear power generation the safest, but it's going to get even safer...

But the following one seems to have been I the US. I do not think there would be any industry where there were no recorded fatalities regardless of where that industry is conducted on this planet.

SL-1

Idaho Falls, Idaho, USA, January 3, 1961

The withdrawal of a single control rod caused a catastrophic power surge and steam explosion at the SL-1 boiling water reactor that killed all the workers on duty at the time.

How did it happen?
On January 3, 1961, workers were in the process of reattaching to their drive mechanisms control rods they had disconnected earlier that day to enable test equipment to be inserted in the reactor core. They lifted the central control rod 20 inches, instead of the four inches that was required. This error caused the reactor to go critical and its power to surge 6,000 times higher than its normal level in less than a second. As a result, nuclear fuel vaporized and a steam bubble was created. The steam bubble expanded so quickly that it pushed water above it against the reactor vessel, which caused it to jump out of its support structure. It hit an overhead crane and then returned to the reactor vessel. In the process, all of the water and some of the fuel was released from the reactor vessel. All three workers on duty received lethal doses of radiation, in addition to trauma from the explosion.

:End of quote:

Fukushima might have happened in Japan, but it was a GE "design and install" plant and the failure mode exceeded 2x the designed potential failure mode.

Collectively the "industry" is leaning from each other's mishaps and near misses and thankfully getting safer as time progresses.

We all owe a debt to those who were at the forefront of the investigations. Marie Curie (unknowingly) gave her life as one of the foundation blocks to get us to where we are today.

GE had nothing to do with the placement of the back up generators, that was 100% TEPCO ( Tokyo Electric Power Co. )...

..."The authors describe the disaster as a “cascade of industrial, regulatory and engineering failures” leading to a situation where critical infrastructure — in this case, backup generators to keep cooling the plant in the event of main power loss — was built in harm’s way.

At the four damaged nuclear power plants (Onagawa, Fukushima Daiichi, Fukushimi Daini and Toka Daini), 22 of the 33 total backup diesel generators were washed away, including 12 of 13 at Fukushima Daiichi. Of the 33 total backup power lines to off-site generators, all but two were obliterated by the tsunami.

Unable to cool itself, Fukushima Daiichi’s reactors melted down one by one.

“What doomed Fukushima Daiichi was the elevation of the EDGs (emergency diesel generators),” the authors wrote. One set was located in a basement, and the others at 10 and 13 meters above sea level — inexplicably and fatally low, Synolakis said.

Warnings ignored

Synolakis and Kânoğlu report that the Tokyo Electric Power Co. (TEPCO), which ran the plant, first reduced the height of the coastal cliffs where the plant was built, underestimated potential tsunami heights, relied on its own internal faulty data and incomplete modeling and ignored warnings from Japanese scientists that larger tsunamis were possible.

Prior to the disaster, TEPCO estimated that the maximum possible rise in water level at Fukushima Daiichi was 6.1 meters — a number that appears to have been based on low-resolution studies of earthquakes of magnitude 7.5, even though up to magnitude 8.6 quakes have been recorded along the same coast where the plant is located.

This is also despite the fact that TEPCO did two sets of calculations in 2008 based on datasets from different sources, each of which suggested that tsunami heights could top 8.4 meters — possibly reaching above 10 meters.

During the 2011 disaster, tsunami heights reached an estimated 13 meters at Fukushimi Daiichi — high enough to flood all of the backup generators and wash away power lines."...

https://news.usc.edu/86362/fukushima-disaster-was-preventable-new-study-finds/

The SL-1 was an experimental reactor being built by the Army....the first of its kind...

..."Not long after dropping the first two nuclear bombs on Japan, the United States began to devise ways of applying its innovations in atomic science to making not only weapons but energy. The country, which lagged slightly behind the U.S.S.R. and the U.K. in the construction of nuclear power plants, established one of its first testing facilities in the small military town of Arco, Idaho.

The U.S. Army built the reactor, known as Stationary Low-Power Reactor № 1 (or SL-1), as an experiment, a prototype intended to pave the way for nuclear-power generators meant to serve remote military facilities in the arctic. "...

https://timeline.com/arco-first-nuclear-accident-f16ec1105b9c

Steve45 have you seen this on the wind power?

https://www.businessinsider.com/climate-effects-of-wind-power-cause-local-warming-2018-10?fbclid=IwAR0RGqejRDcvkIssiCM0tqGZW88Iw5nd5iF5-o5mThmQuW1nxeUbCwstJBc

This was a big "duh" because energy is neither created or destroyed so when we took wind energy out to make electric energy some happens.

Not to mention all the birds, pollinators, and bugs that get toasted too.

Unless I missed it, I did not see any discussion or mention of the Rocky Flats, Colorado deep well injection of radioactive waste back in the 60's and 70's. https://scits.stanford.edu/sites/default/files/evans_0.pdf I believe it was over 7000 feet down. There were numerous earthquakes from that injection up to 5.4 magnitude and lots of denial by the owners until it was proven that it was due to the injected fluid. We will probably never know for sure where all the fluid went too. I think this needs to be part of the discussion and all the reasons we stopped doing it. I know that hydraulic fracking had similar issues and yes I know they have resolved that issue pretty much but the fact remains that we built Yucca Mountain and are not using it is a disgrace and sin to our taxpayers. I would rather have it in Yucca Mountain where we can get to it if an unexpected issue arises rather than in the ground where if something goes wrong (aka something we did think about happens) our options and costs to address any problems are exponentially higher. Like this possible scenario https://www.denverpost.com/2018/11/15/rocky-flats-drilling-plans-dropped-highlands-natural-resources/

These are not injection wells.....

You are correct about it not being an injection well. I miss read part of it due to the original comment containing the following

SANDIA

This sounds like a good idea, eliminates transport of nuclear waste, no added NIMBY, a tried and true technology we already use Injection well strategy for toxic and hazardous waste disposal and have for years..

There seems to be some misconception by some here that these "containers" can leak or rupture...Highly radioactive waste is vitrified which means the radioactive material is mixed with silica sand and heated to 2000°+F forming a glass block, the material is sealed in the glass and can not leak because it is a solid chunk...these glass chunks are then encapsulated in stainless steel containers and welded shut...Most spent fuel that is stored on site is stored in dry cask storage containers, there is no liquid....The containers are large and have layers of steel and concrete...

https://www.forbes.com/sites/jamesconca/2018/03/06/will-we-actually-get-a-place-to-store-our-nuclear-waste/#6676634223a0

As a curiosity (not particularly a worry yet) I wonder how much temperature rise occurs in the middle of these tanks. I suspect not very severe, but someone's back-of-envelope calculation (or an actual sample test) would be interesting.

There are different designs I guess but they all operate pretty much the same...the casks are ventilated so that air flow removes the heat generated by natural convection, the immediate storage tank is of course sealed but there is a space between the tank and the outer concrete wall for this purpose....The casks are said to generate around 25 kW of heat and gradually cool...You could definitely feel the heat standing next to one...

https://inis.iaea.org/collection/NCLCollectionStore/_Public/37/088/37088784.pdf

https://public-blog.nrc-gateway.gov/2016/02/11/dry-casks-101-managing-heat/

That sounds reasonable.