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Stuff You Should Know

What To Do With All This Nuclear Waste?

Published November 4, 2025
View Show Notes

About This Episode

Josh and Chuck discuss what nuclear waste actually is, how it is produced in nuclear reactors, and the different forms it takes. They explain current storage methods like spent fuel pools and dry casks, national and international strategies for long-term disposal including Finland's deep geological repository, and the stalled Yucca Mountain project in the U.S. They also explore emerging ideas such as recycling spent fuel, transmutation, vitrification into glass or ceramics, and touch on policy, security risks, and connections to artificial intelligence-driven demand for nuclear energy.

Topics Covered

Nuclear power Nuclear waste management Radioactive contamination Renewable energy and decarbonization Nuclear fuel recycling Pollution Climate change projections Artificial intelligence ChatGPT Waste Isolation Pilot Plant

Disclaimer: We provide independent summaries of podcasts and are not affiliated with or endorsed in any way by any podcast or creator. All podcast names and content are the property of their respective owners. The views and opinions expressed within the podcasts belong solely to the original hosts and guests and do not reflect the views or positions of Summapod.

Quick Takeaways

  • Most nuclear waste from power plants is in the form of solid fuel pellets and assemblies, not glowing green goo, and the highest-level waste represents a small fraction of volume but the vast majority of radioactivity.
  • Spent fuel is first stored for years in deep water pools on-site to cool and allow short-lived isotopes to decay before being moved to heavily engineered dry casks.
  • The U.S. lacks an operational long-term geological repository; Yucca Mountain was legally designated as the only site but was politically halted, leaving spent fuel effectively parked on-site at reactors.
  • Finland's Onkalo facility is the first deep geological repository close to operation, burying canisters in bedrock and clay far underground, but even its "permanent" timescale is uncertain compared with some isotopes' half-lives.
  • Low-level waste like contaminated clothing and tools is far easier to handle than high-level spent fuel and can be disposed of in specialized landfills that allow it to decay over a few decades.
  • The U.S. Waste Isolation Pilot Plant in New Mexico stores long-lived transuranic defense waste in deep salt formations that are expected to self-seal over time.
  • Decommissioned nuclear plants still have to manage spent fuel pools, dry casks, and contaminated water, with treated and diluted coolant water ultimately released into nearby bodies of water.
  • Recycling and reusing spent fuel in advanced reactors or by extracting fissile material could drastically reduce the volume and danger of nuclear waste and even power the U.S. for many decades, but pose security and proliferation risks.
  • Technologies like particle-accelerator transmutation and vitrification into glass or ceramics could convert highly radioactive isotopes into less dangerous forms or lock them into stable matrices.
  • Some nuclear-waste innovation is being driven by companies tied to artificial intelligence, raising both hope for better recycling and concern about coupling rapidly advancing AI with nuclear infrastructure.

Podcast Notes

Introduction and framing the nuclear waste issue

Pop culture image of nuclear waste vs reality

Hosts reference Homer Simpson and The Simpsons' depiction of glowing green rods and sludge[2:13]
• They mention a rod flying into Homer's hood and the "inanimate carbon rod" as employee of the year as a cultural touchstone for how people picture nuclear material.
Real nuclear waste does not glow green and is usually solid, not goo[3:23]
• Most nuclear waste consists of solid pellets and assemblies made of metal and various elements, originally uranium fuel.
There can be sludge-like waste but it is atypical[2:31]
• They describe a type of toxic nuclear sludge with a peanut butter-like consistency as a closer real-world analog to the cartoon ooze.

How spent fuel arises and why it is concerning

Uranium fuel assemblies are used for roughly five or six years before being considered spent[3:46]
• After undergoing fission for years, the fuel says "I'm spent, get me out of here" and is replaced, even though some usable energy remains.
Spent fuel is the most dangerous category of nuclear waste[3:58]
• It is highly radioactive, generates significant heat, and requires the most careful handling and long-term management.

Physical description of fuel pellets and scale per person

Fuel pellets are about half a thumb in size[4:20]
• Josh and Chuck joke about describing them as "half a thumb" rather than using metric, clarifying it's the top thumbprint section, the "thumb sprout."
Each person's lifetime nuclear waste would fit into about a hockey puck[6:04]
• They say if all the nuclear power you personally used over your lifetime came from nuclear plants, the resulting waste for you would compress into a hockey-puck-sized volume.
Total U.S. spent fuel is about 90,000 tons but still relatively compact[7:06]
• They emphasize this tonnage sounds eye-popping but is not a huge volume compared to many industrial wastes; the issue is danger and longevity, not bulk.

Lack of permanent solutions and promise of future ideas

No place in the world yet has an unquestioned permanent solution for high-level nuclear waste[4:45]
• Finland is closest with a deep geological repository, but the hosts put "permanent" in scare quotes given multi-millennial timescales.
The U.S. canceled a proposed repository in 2010 and still lacks a replacement[5:05]
• They note the U.S. was going to build such a facility around 2010 but did not, leaving waste in interim storage.
Current approach is essentially stashing waste on-site and hoping for better future solutions[5:22]
• Josh characterizes the present path as "kind of a dumb, unnecessary road" and hopes smarter approaches prevail as new ideas emerge.

How nuclear reactors and fuel assemblies work

Basic mechanism of power generation in nuclear plants

Nuclear plants, coal plants, and gas plants all fundamentally boil water to turn turbines[8:03]
• In all these systems, the goal is to create steam that drives a turbine; the distinction is the heat source (uranium-235 vs. coal or natural gas).
Uranium-235 pellets act as the fuel[8:14]
• Small uranium-235 pellets, about half a thumb in size, are loaded into long metal tubes to form fuel rods.

Fuel rods, assemblies, and reactor core configuration

Pellets are placed in fuel rods, rods are bundled into fuel assemblies[8:25]
• Several dozen rods make up a fuel assembly, and depending on the reactor there can be roughly 150 to 800 assemblies in the core.
Reactor cores and assemblies are kept underwater[8:45]
• Water supports the chain reaction and also cools the core, with constant flow in and out to keep temperature relatively stable.

Advantages and drawbacks of nuclear power

Nuclear plants produce no combustion emissions during operation[9:25]
• They describe nuclear plants as self-contained systems without the smokestack pollution of fossil fuel plants.
However, spent fuel creates a long-term waste problem[9:55]
• Audience reaction is framed as "hooray" for no emissions followed by "aw" when reminded of high-level waste.
Advanced reactor designs may improve the profile of nuclear power[9:39]
• They briefly note that newer advanced designs coming down the pike could make nuclear an even better energy source if waste is handled intelligently.

Handling spent fuel in pools and dry cask storage

Fuel cycle and timing of fuel removal

Reactors replace about a third of fuel assemblies every 1.5 to 2 years[10:39]
• Although overall assemblies can operate for about five or six years, practical refueling cycles swap out portions periodically.
Fuel considered "spent" still contains usable energy[9:55]
• They stress that "on empty" is misleading; old-school reactors just cannot efficiently extract the remaining energy from partially depleted fuel.

Spent fuel pools and why they are essential

Assemblies are moved underwater via canals into spent fuel pools[11:25]
• Fuel never leaves water during transfer; there are canals connecting core and pool, and Josh jokes that they are carried on gondolas along these canals.
Spent fuel pools are deep stainless steel basins with about 40 feet of water[11:42]
• Assemblies sink to the bottom, leaving 20-30 feet of water above them, and remain there for years.
Pools serve to cool fuel and allow some radioactivity to decay[12:24]
• They explain that over two to five years in pools, some short-lived isotopes decay, but the main purpose is to remove heat so assemblies will not combust.
If hot assemblies were exposed to air, they could overheat and explode[13:00]
• An explosion would spread dangerous isotopes like cesium-137 into the air, environment, and food chain, posing serious health risks.

Dry cask storage on reactor sites

Once cooled, fuel is transferred from pools into dry casks stored on-site[14:20]
• Initially, all waste remained in pools for decades, but as pools filled, plants adopted dry casks from the 1970s onward.
First U.S. dry cask facility opened in 1986 at Surry Nuclear Power Plant[14:43]
Dry casks are large, heavy containers with multiple protective layers[14:48]
• Each cask is roughly 20 feet tall, 8 feet in diameter, weighs about 100 tons, and holds several dozen fuel assemblies sealed in a steel canister.
• Air is removed from the steel canister and replaced with inert gas, then encased in thick concrete that includes boron, magnetite, barite, and polymer fibers to absorb radiation and add strength.
Dry casks are effectively "parked out back" on or near the surface[14:04]
• Josh emphasizes the ad hoc nature of this arrangement, likening it to tossing sealed casks behind the plant to sit until a long-term plan exists.
Dry casks are only rated for about 100 years of storage[15:49]
• Because the first U.S. casks went into service around 1986, roughly 40 years of their design life have already elapsed, underlining the urgency of long-term solutions.

U.S. storage policy, Yucca Mountain, and interim consolidated sites

Interim consolidated storage proposals in New Mexico and Texas

The Nuclear Regulatory Commission is reviewing applications for large interim storage sites[16:55]
• These Consolidated Interim Storage Sites would aggregate dry casks from multiple plants in New Mexico and Texas.
Worldwide, about 70 percent of spent fuel remains in pools and 30 percent in dry casks[16:43]
Interim sites are still temporary and generally near the surface[17:26]
• Although designed to withstand natural disasters, these sites do not involve deep burial in bedrock and thus are not true permanent repositories.

Yucca Mountain project and its political cancellation

Yucca Mountain in Nevada was the designated U.S. deep geological repository[17:38]
• It received regulatory approval from the NRC and EPA, but Nevada opposed it and the Obama administration canceled the project in 2010.
A 1987 law restricted DOE and NRC to Yucca Mountain as the only long-term site[17:38]
• Congress specified that nuclear waste could only be geologically stored at Yucca, and lawmakers never updated this after the project stalled.
Resulting policy vacuum has left long-term disposal "totally in limbo"[18:10]
New Mexico's proposed interim site could hold about 120,000 tons[18:24]
• Since the U.S. currently has around 90,000 tons of spent fuel and adds roughly 2,000 tons per year, such a site could be full in 15 years.
Nuclear expansion is proceeding despite unresolved waste issues[18:06]
• Josh notes that the industry is "go, go, go" and not waiting for a permanent waste solution, increasing the pressure on storage timelines.

Finland's Onkalo repository and long-term timescales

Design and construction of Onkalo deep geological repository

Onkalo is the first deep geological repository nearing completion[21:37]
• Located in Finland, Onkalo (meaning "cavity" or "pit") is designed to store spent fuel about 1,430 feet below ground in stable bedrock.
Fuel is placed in steel canisters surrounded by a copper layer[23:07]
• The canisters are encapsulated in about a 2-inch-thick copper shell, chosen because copper does not corrode under the anaerobic conditions at that depth.
Canisters are stacked in vertical shafts and backfilled with bentonite clay[23:25]
• Shafts about 30 feet deep are drilled off the main tunnels; canisters are stacked, then filled and sealed with compressed bentonite clay.
• Bentonite swells when contacted by water, theoretically sealing gaps and preventing water flow, though Josh jokes that designers must hope it does not over-pressurize and pop canisters.

Capacity and claimed longevity of the repository

Onkalo is designed to hold about 3,000 canisters[25:01]
• This capacity is expected to be sufficient for waste from Finland's five reactors over about 120 years of operation.
Repository is claimed to last about 100,000 years[25:32]
• The idea is that after 100,000 years, remaining radioactivity would be at a level considered no longer dangerous, though the hosts question this certainty.

Disagreement and uncertainty over how long waste is dangerous

Different sources give wildly different risk timescales[25:40]
• Some say nuclear waste is dangerous for only decades, others say thousands, tens of thousands, or point to isotopes with half-lives on the order of billions of years.
Examples of problematic isotopes[26:04]
• They mention an isotope of uranium with a half-life of 4.5 billion years, and iodine-129 with a half-life of 15 million years, as especially long-lived concerns.
• Cesium-137, by contrast, has a half-life around 30 years but is dangerous because it spreads easily into the environment and food chain.
Hosts suspect long times like 100,000 years may be somewhat arbitrary[27:01]
• Chuck jokes they may have picked a time horizon far enough that people will stop caring about descendants, noting the lack of clear, consistent scientific messaging.
Deep burial reflects an abundance-of-caution mindset[27:29]
• Given uncertainties, they see deep geological disposal as erring on the side of caution: bury it as deep as practical and metaphorically dust off hands.

Other nuclear waste categories and the Waste Isolation Pilot Plant

Low-level nuclear waste and its disposal

High-level waste is only about 3 percent of volume but 95 percent of radioactivity[28:05]
Over 90 percent of nuclear waste is low-level material[28:19]
• Low-level items include contaminated protective clothing, tools, and disposable materials with minor radioactive dust or residue.
The U.S. has four low-level disposal sites[28:19]
• Facilities are located in South Carolina, Washington State, Utah, and Texas, where waste is encased in concrete and backfilled similarly to landfills.
Low-level waste generally decays to safe levels in 20-30 years[28:45]

Transuranic defense waste and the Waste Isolation Pilot Plant (WIPP)

Transuranic waste has very long half-lives and comes mainly from weapons programs[29:07]
• Produced when plutonium captures neutrons during weapons plutonium production, forming isotopes like neptunium and americium, plus plutonium-239 itself.
Examples of long-lived transuranic isotopes[29:09]
• Neptunium is cited with a half-life of about 2.14 million years, and plutonium-239 has a half-life over 24,000 years.
Transuranic waste is both dangerous and potentially useful[29:07]
• Because it remains highly fissile, it could theoretically be reused for energy if appropriate technologies and safeguards existed.
Currently, transuranic waste is stored at the Waste Isolation Pilot Plant (WIPP) in New Mexico[30:07]
• WIPP is located in deep underground salt layers that have little to no groundwater flow, and the salt is expected to creep and seal over time around the waste.
Episode nuclear semiotics discussed WIPP's future warning problem[30:17]
• They reference a prior episode about designing symbols and messages to warn people 10,000 years in the future to avoid the WIPP site.

Note about extensive back catalog of related episodes

Hosts mention several past nuclear-related episodes[30:41]
• They cite Fukushima and a 2014 episode on whether nuclear fusion reactors can save the world.
They encourage listeners to explore hundreds of older episodes[31:30]
• They explain how to see "show all episodes" in podcast apps and praise their website search for finding topics.

Decommissioning plants and handling contaminated water

Decommissioning nuclear power plants

Reactor sites must eventually be shut down and decommissioned[32:58]
• In the U.S., about 60 years is the maximum operating life for a reactor before decommissioning is required.
Most decommissioning waste is low-level[33:03]
• Only about 1 percent of the concrete and materials from a decommissioned plant are significantly radioactive; the rest can be treated as regular construction waste.
Proposals exist to reuse slightly contaminated concrete[33:25]
• One idea is to recycle decommissioned plant concrete for use in encasing dry casks and other nuclear waste structures to keep radioactivity within specialized domains.
Decommissioned sites may still host pools and casks for decades[33:59]
• Even after power production stops, plants continue to manage spent fuel in pools and dry casks on-site due to lack of a national repository.

Treatment and release of radioactive cooling water

Spent fuel pools contain large volumes of radioactive coolant water[34:07]
• Once fuel is moved to dry casks, operators are left with pools of contaminated water that must be processed.
Standard practice is to treat, dilute, and discharge water into natural bodies[34:41]
• Plants are usually sited near rivers, lakes, or oceans to support this strategy, as well as cooling needs.
Hosts express skepticism about how "clean" the water can really be[34:59]
• Chuck says he is not generally conspiratorial but finds it hard to believe water from spent fuel pools can ever be truly safe to dump.
Treatment involves filtering out radionuclides and then diluting the remainder[35:09]
• Processes exist to remove many radioactive particles, but regulators rely on massive dilution with fresh water before release to meet safety thresholds.
Josh criticizes dilution and discharge as a crude solution[35:05]
• He notes that, even with treatment, the fallback is essentially "dump it in the ocean" and asks whether that is really the best we can do at present.
They reference The Simpsons' three-eyed fish "Blinky" as a cultural image of polluted water[35:54]

Future approaches: recycling, advanced reactors, transmutation, and vitrification

Recycling spent fuel and advanced reactor designs

There is renewed interest in recycling high-level waste[38:34]
• Josh describes a "new spirit" of recycling in the nuclear industry aimed at extracting remaining energy and reducing waste hazard.
Advanced reactors could be designed to burn partially spent fuel[39:05]
• More sensitive reactors might use fuel that old-generation plants consider too depleted, unlocking additional energy.
Reprocessing can extract usable fissile material from spent fuel[39:17]
• By chemically processing spent assemblies, operators could separate uranium and plutonium to make new fuel pellets while leaving behind less-radioactive residues.
Oklo estimates existing U.S. spent fuel could power the country for 150 years[40:09]
• Oklo, a startup, asserts that if we harnessed the remaining energy in today's spent fuel stockpile, it could supply all U.S. electricity needs for a century and a half.
Burying spent fuel without reusing it would waste enormous energy[40:09]
• Josh calls it "so stupid" to simply entomb this fuel in deep geological repositories such as Yucca Mountain without first extracting its energy.
Delay on Yucca Mountain may be a "lucky break" for recycling innovation[40:19]
• He argues that the limbo around Yucca has unintentionally bought time for better ideas, rather than locking us into bury-and-forget strategies.
Oklo claims it can recycle and reuse about 94 percent of uranium in spent fuel[40:37]
• Oklo holds a DOE license for a recycling plant in Oak Ridge, Tennessee, and is one of ten companies in a reactor pilot program to develop recycled-fuel reactors.

Security and proliferation risks of reprocessing

Even partially spent fuel poses security risks if reprocessed[40:37]
• Chuck notes that material recovered for peaceful reactors could also be diverted for dirty bombs if not tightly secured.
Extracting plutonium is especially concerning due to weapons applications[41:33]
• Separated plutonium is the core ingredient for nuclear weapons, raising fears that hostile states or groups could steal it from poorly secured facilities.
Josh says security concerns are the main obstacle to recycling[42:16]
He argues similar safeguards used for nuclear stockpiles could protect recycling sites[42:10]
• He questions why we can secure warhead stockpiles but not reprocessing plants, suggesting this is a solvable engineering and policy problem.
Likely need close government involvement and high security standards[42:32]

Intersection of nuclear innovation and artificial intelligence

Many nuclear startups are funded by AI-linked figures and interests[42:42]
• Josh mentions that Oklo is backed by Sam Altman of OpenAI, and that many projects are motivated by the need for cheap power for AI data centers.
Humanity may benefit from better waste handling as a side effect of AI power demand[43:06]
Coupling fast-moving AI and nuclear infrastructure is worrisome[43:10]
• Josh says this nexus makes some people, including him, uneasy, since these are both high-stakes technologies evolving quickly.
They recommend the book "If Anyone Builds It, Everyone Dies" for AI risk context[43:38]
• Josh describes the book by Eliezer Yudkowsky and Nate Soares as an accessible explanation of catastrophic AI risk and a critique of the pace of AI development.

Transmutation via particle accelerators

Transmutation aims to convert highly radioactive isotopes into less dangerous ones[45:32]
• The concept is to take the most radioactive portions of the waste stream and bombard them with neutrons in a particle accelerator.
Neutron bombardment can change nuclear composition and stability[45:18]
• Bombardment may knock off particles or add neutrons, producing isotopes that decay faster or are more stable and non-radioactive.
In principle, transmutation could generate energy while destroying waste[46:02]
• They note that this is largely theoretical but could both reduce long-lived waste and produce usable power during the process.

Vitrification and ceramic immobilization of waste

Glass logs can immobilize radionuclides through vitrification[46:27]
• Waste is melted with glass-forming minerals to create solid "glass logs" where radioactive atoms are part of the glass matrix, not merely contained inside.
Glass provides a durable, tight-bonded matrix that is hard for water to penetrate[46:36]
Ceramic materials can serve a similar immobilization role[47:16]

Recycling fissile material and reducing overall waste volume

Reprocessing aims to recover uranium and plutonium from waste streams[47:28]
Recycled mixed-oxide fuel can be made by combining extracted materials[47:55]
• They mention that using eight old pellets can yield one new pellet of mixed uranium-plutonium oxide (MOX) fuel, a relatively efficient recycling ratio.
Repeated recycling can be done until energy content is too low[48:08]
Even without using recovered fuel, isolating it would drastically shrink high-level waste[48:30]
• If high-energy material constitutes about 1 percent of U.S. nuclear waste, extracting it would reduce 90,000 tons of high-level waste to about 900 tons of the most problematic fraction.
They conclude that aside from security risks, there is little downside to processing waste to remove high-energy components[48:54]

Listener mail: inmate counsel and legal support in prisons

Email from a lawyer about inmate counsel at Angola and beyond

Listener Kelly writes about representing incarcerated people and the Angola 3[49:30]
Inmate counsel are incarcerated individuals who learn and teach law[49:47]
• They draft motions and legal filings for others in prison and advocate for incarcerated communities as a whole.
There is no right to free counsel for post-conviction relief[50:01]
• Because indigent defendants generally do not get appointed lawyers for appeals or post-conviction work, inmate counsel often become the only route to legal help.
Inmate counsel have helped thousands of incarcerated people in Louisiana[49:47]
Kelly recommends the book "The Jailhouse Lawyer" by Calvin Duncan about this system[49:40]
Hosts express interest in doing a short episode on inmate counsel[50:20]
They thank Kelly for her work helping people harmed by the justice system[50:48]

Show sign-off

They invite listeners to email suggestions and sign off as Stuff You Should Know, a production of iHeartRadio[51:09]

Lessons Learned

Actionable insights and wisdom you can apply to your business, career, and personal life.

1

Problems that unfold over decades or centuries, like nuclear waste management, cannot be left to ad hoc "we'll figure it out later" strategies; they require deliberate planning, conservative assumptions, and institutional commitments that outlast current political cycles.

Reflection Questions:

  • • Where in your own work or life are you relying on a vague future fix instead of designing a robust long-term plan now?
  • • How could you build in safeguards or checkpoints so that important long-term risks are revisited even if leadership or circumstances change?
  • • What concrete step could you take this month to move one long-horizon issue you face from wishful thinking to an actual written strategy?
2

Before discarding any resource as "spent" or useless, it is worth asking what residual value remains and whether new technologies or processes could unlock that value while reducing associated risks.

Reflection Questions:

  • • What assets, data, or byproducts in your environment are currently treated as waste but might have secondary uses if processed differently?
  • • How might reframing something you see as a liability (time, materials, relationships) into a potential resource change your approach to it?
  • • What is one "waste" stream in your business or personal routines you could audit this week to identify hidden value?
3

Innovations that reduce risk often introduce new categories of risk, such as security or misuse, so any ambitious solution needs to be paired with equally ambitious governance, monitoring, and access control.

Reflection Questions:

  • • Which of your current projects or tools could create serious problems if they were misused or fell into the wrong hands?
  • • How can you design controls, oversight, or fail-safes alongside your innovations rather than bolting them on after the fact?
  • • What is one security, ethics, or misuse scenario you should deliberately plan for around a system you are responsible for?
4

When dealing with complex, uncertain systems, it is often wiser to err on the side of overprotection and redundancy than to trust optimistic projections that might later prove incomplete or wrong.

Reflection Questions:

  • • In what area are you currently relying on best-case assumptions that might expose you if conditions change?
  • • How could you build an extra margin of safety-time, budget, redundancy, or backup options-into your most critical plans?
  • • What is one decision you are making this quarter where you should explicitly consider and plan for the worst credible scenario?
5

Technical progress (like AI and advanced nuclear) can move faster than our collective ability to manage its consequences, so aligning innovation pace with thoughtful societal oversight is a strategic necessity, not an optional brake.

Reflection Questions:

  • • Where are you or your organization prioritizing speed over careful consideration of downstream impacts?
  • • How might involving a wider range of stakeholders-users, regulators, critics-improve the quality and robustness of your next major initiative?
  • • What is one current project where you should slow down slightly to add a review, test, or ethical check before scaling it up?

Episode Summary - Notes by Parker

What To Do With All This Nuclear Waste?
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