Progress has been made since the height of the Cold War in reducing the number of nuclear weapons. Thousands of warheads have been dismantled and entire missile systems retired. But much remains to be done, just as it does with finding better ways to dispose of the fissile materials left behind.

Dismantling nuclear weapons does not destroy the highly enriched uranium (HEU) or separated plutonium contained in the bomb. And manufacturing those critical materials is by far the most difficult part of building nuclear weapons.

This is the orphan on the doorstep of nuclear weapons and nuclear power alike. Finding better ways to dispose of fissile materials is not just a technical challenge – it is a moral, environmental, and political imperative. The safety of our generation, and of generations to come, is increasingly impacted by what we do with our nuclear garbage today.

Thousands of Skilled Machinists

Different items are handled in different ways when nuclear weapons are dismantled. The casing, electronics, and explosives may be recycled or scrapped, but the fissile uranium or plutonium elements remain as deadly as ever.

Those materials are dangerous primarily for two reasons:

• Gun-type atomic bombs, like the one dropped on Hiroshima, are simple enough that the scientists who designed them decided they required no testing. They can be constructed by any one of thousands of skilled machinists worldwide, able to acquire some basic explosives, ordinary machine shop tools, and access to the internet for readily available details of how they are made.

Implosion-type atomic bombs, like the one dropped on Nagasaki, are harder to build, and hydrogen bombs are more difficult yet, but obtaining fissile material is always the greatest barrier against building nuclear weapons of any kind.

• Fissile materials are radioactive and toxic. Deadly health hazards exist, along with environmental hazards so extreme that the materials must be completely isolated from nature for tens of thousands of years.

Over 1,800 tons of separated plutonium and HEU exist in the world today – enough for more than 100,000 nuclear weapons. Most is stored in secure facilities, but security is never perfect. Perfection in this case requires that unused fissile materials be completely destroyed or isolated beyond any realistic means of recovery. But how? 

Efforts to Address the Problem

The United States and Russia took some steps in the past to reduce fissile stockpiles.

One initiative was the 1993 HEU Purchase Agreement, where 500 tons of HEU from dismantled Russian weapons were blended with natural uranium to produce Low-Enriched Uranium (LEU) for civilian power reactors. For twenty years, 10% of America’s electricity came from dismantled Russian nuclear warheads!

Other countries have also eliminated some HEU, particularly from research reactors at universities. But progress has stalled, and worse yet: HEU production in some countries is rising again.

Another complication is that plutonium cannot be down-blended like uranium can, since a ‘weaker’ form of plutonium does not exist to blend it with. Permanently disposing of plutonium requires destroying it or securely isolating it for thousands of years. But plenty can go wrong when trying to contain something so dangerous for so long.

A prime example was the 2014 Valentine’s Day accident when drum #68660 exploded at the DOE’s Waste Isolation Pilot Plant (WIPP) in New Mexico. WIPP is the only operating nuclear geological repository in the world, but it only accepts waste from nuclear weapons production.

The explosion contaminated a third of the site, and some radiation reached the surface, where workers were exposed. Neither the radiation released nor the exposure levels appeared to be serious, but…what???

How can a site licensed for 10,000 years of safe storage blow up after fifteen?

Kitty litter.

A comprehensive DOE investigation revealed that Los Alamos technicians used the wrong brand of cat litter to absorb the liquid waste in that drum. It seems the brand Wheat Scoop contains organic compounds that react violently with fissile materials. 

The disaster cost over $2 billion to clean up, but what if the drum had exploded in the open air during transportation to the site? Plans to isolate fissile materials for 100,000 years appear to need more study when the DOE’s best effort could not go fifteen years without suffering a catastrophe. 

Why Current Methods Fall Short

Numerous methods for disposing of fissile materials have been proposed, and some have been tried, but each has its drawbacks.

• Downblending HEU: HEU can be denatured by mixing it with natural uranium to produce LEU reactor fuel. While effective, it requires significant political will to destroy something so difficult and expensive to acquire in the first place – especially when critics say it’s still necessary for national defense. As a result, only a fraction of global HEU has been downblended to date.
• Mixed Oxide Fuel (MOX): The way that plutonium can actually be denatured is by mixing it with natural uranium to create MOX reactor fuel. But the process is expensive, technically challenging, and controversial.

Amid growing awareness of MOX disadvantages, construction was permanently halted in 2018 on the Mixed Oxide Fuel Fabrication Facility (MFFF) at the DOE’s Savannah River site in Georgia. About 70% complete after eleven years of construction, the facility’s estimated cost had also doubled from $4.9 billion to $10 billion, with annual operating expenses expected to be at least $500 million after that.

• Vitrification: Plutonium can be mixed with high-level radioactive waste and encased in glass or ceramic for permanent disposal using a vitrification process. This approach is being explored but has not been widely implemented due to its cost and disagreements over where the treated waste would eventually go.
• Long-term storage: At present, most fissile material is simply kept in secure facilities where it is reasonably safe for the time being – a temporary solution that occurred by necessity simply because there was nowhere else for it to go.

All of which means that vast quantities of fissile materials sufficient for thousands of nuclear weapons remain scattered across the globe.

What Would a Better Approach Look Like?

A better approach to fissile material disposal must meet several criteria:

• It must make the material permanently unusable for weapons.
• It must minimize environmental risks and radiation exposure.
• It must be economically and technically feasible.
• It must be verifiable and inspire genuine confidence.

Several strategies could be combined:

1. Accelerate HEU Downblending

The HEU Purchase Agreement proved that large amounts of HEU can be downblended for use in civilian reactors to turn weapons into watts. This model could be expanded globally, with incentives for countries to convert their HEU to LEU.

2. End Plutonium Reprocessing

Plutonium was first separated from spent reactor fuel on the assumption that many ‘fast-reactors’ would soon be built that burnt it instead of uranium. But fast reactors have experienced serious problems, and less than twenty are operating today, none of which has turned a profit. Yet countries like Japan and France continue reprocessing, adding to global stocks of separated plutonium.

But why? Tons of excess plutonium already exist. And if fast reactors experience a future breakthrough, plenty of spent reactor fuel is constantly being produced in current reactors to extract more plutonium from. But if the long-awaited breakthrough never happens, separating plutonium is just a waste of time that produces hazardous, toxic, and radioactive waste, which is difficult to eliminate and good for nothing but nuclear weapons.

International Oversight

This is key to managing fissile materials. Despite serious resistance to the idea, all fissile materials must be placed under international control with complete transparency for all nations involved. This concept is not new. President Dwight D. Eisenhower proposed it during his United Nations speech, Atoms for Peace in 1953.

Then former International Atomic Energy Agency (IAEA) director Mohamed ElBaradei wrote an article for The Economist in 2004 proposing that uranium enrichment and plutonium reprocessing be controlled internationally. The idea took off, with support even coming from unexpected quarters like businessman Warren Buffett, who pledged $50 million in seed money.

But America and Russia killed it. They insisted instead that fuel be supplied to any nation that agreed to give up its treaty rights to a full and independent nuclear fuel cycle of its own, but they themselves would not forgo enrichment or reprocessing. Yet it’s interesting to note that China supported the proposal and never wavered.

The IAEA

The IAEA is an independent arm of the United Nations established to promote the peaceful use of nuclear energy and discourage its military use. A major activity is monitoring nuclear facilities to ensure that fissile material is not diverted for military use by nations that have officially renounced building nuclear weapons.

The IAEA itself is the perfect candidate to enforce international control of fissile materials, but doing so requires increasing its annual budget a hundredfold to at least $50 billion.

Fifty billion for the IAEA may sound like a lot, but America’s 25% share would be less than $12 billion. Compare that to the $95 billion the US Congressional Budget Office estimates America will spend on nuclear weapons programs for each of the next ten years. And that’s without counting the half-trillion more the military wants for new nukes.

Altogether, the world spends close to $300 million a day on nuclear weapons – nearly $12 million an hour! It goes without saying that the money could be spent in better ways.

Finland’s Approach

Of the many proposals being considered for the disposal of fissile materials, the leading contender is permanent burial in underground geological repositories. A possible site beneath Yucca Mountain in Nevada was considered but ultimately rejected for political reasons.

So WIPP remains the only operating nuclear repository in the world at present. However, Finland will soon open a new repository that is licensed to accept commercial nuclear waste. Spent reactor fuel-tubes are being placed directly into heavy cast iron shells, then encased in two-inch thick, pure copper canisters able to withstand groundwater corrosion for millions of years.

The sealed canisters will then be transported to Finland’s new repository and covered with bentonite clay in solid bedrock caverns 1,500 feet down. The hazards associated with transporting those materials to plutonium reprocessing or MOX fuel fabrication facilities, and then again to end-user power plants, are eliminated.

As is a need to transport radioactive garbage to unbuilt glass vitrification plants before travelling again to a central repository. The toxic and radioactive waste streams produced by all three of those methods are also avoided.

A Better Way

Finland’s approach toward nuclear waste disposal is brilliant, but some competition has arisen that promises to dispose of fissile materials in the safest, cheapest, and quickest way possible. It combines the critical element of Finland’s plan with a concept under development by a Berkeley, California startup called Deep Isolation, Inc. In 2019, Deep Isolation used existing fracking technology to successfully demonstrate placing and retrieving a mock steel waste canister in a borehole thousands of feet deep.

This economical method appears to be a breakthrough. Canisters in boreholes up to three kilometers deep offer superior environmental isolation than those in much shallower central repositories. And Deep Isolation’s approach cuts the need to transport nuclear waste dramatically.

The International Panel on Fissile Material says over 10,000 tons of hazardous heavy metal is generated annually in nuclear reactors alone. Rather than store it indefinitely in expensive dry-casks onsite, Deep Isolation’s approach would bury it immediately without transporting it on public roads. Smaller amounts of unwanted uranium and plutonium could be mixed in with the waste and disposed of in that way as well.

This is an incredible advantage! The immediate concern with central repositories is that the long-distance waste often travels to get there. The ever-present possibility of accidents, or perhaps even terrorists armed with anti-tank weapons, cannot be ignored.

But the weakness in Deep Isolation’s plan is the canisters they used. Good for tens of thousands of years, Alloy 625 is one of the best steels for resisting groundwater corrosion. But it cannot compete with copper canisters, good for millions of years. 

Our Proposal

This blog proposes combining  Deep Isolation’s borehole concept with Finland’s copper canister approach. Boreholes can be drilled fast with existing technology and cost a fraction of what central repositories do.

And remember WIPP. Accidents happen no matter how careful we are. Would an exploding canister buried two kilometers beneath the Earth in a strung-out, sealed borehole have the same impact as one stored next to many other canisters in a relatively shallow central repository?  Borehole storage is inherently safer, in addition to avoiding the expense and hazard of transporting something so dangerous over public roads. Tough copper canister,s good for millions of years, seal the deal.

Safer, better, cheaper, faster. It’s hard to argue with that.

A Policy Choice

At Our Planet Project Foundation, we believe that placing fissile materials under international control is key to avoiding a nuclear day of reckoning. Nuclear disarmament is only complete when the materials that make them possible are no longer available to those who would use them.

By choosing to dispose of fissile material responsibly today, we build a safer world for ourselves and especially for our children tomorrow. After all, don’t they deserve it?