A Tragic Policy Error!
The UK’s Decision to Immobilize Valuable Reactor-Grade Plutonium that Could Have Fueled a Clean Energy Revolution
Substantive content by Erik Townsend with research and calculations from ChatGPT 4o
Overview
In a recent decision, the United Kingdom has decided to immobilize its 140 metric tons of reactor-grade plutonium (RGPu) and dispose of it permanently in geological storage. This RGPu stockpile, accumulated over decades through spent nuclear fuel reprocessing, will now be rendered useless and buried at significant expense to the British taxpayer. While this approach was intended to mitigate proliferation risks, it also squanders a once-in-a-generation opportunity to harness this material for transformative energy solutions that could power the nation for decades. The perception of proliferation risks that brought about this decision was badly misguided and no significant proliferation mitigation benefits will be realized.
This article explores the implications of this decision, the potential of using this RGPu to produce MOX (mixed oxide) fuel for existing nuclear reactors, and the even greater opportunity to use this RGPu in concert with the revolutionary possibilities offered by Copenhagen Atomics’ thermal-spectrum molten salt breeder reactor (TS-MSBR) technology. Finally, we’ll examine the economic and environmental benefits of an alternative path that integrates TS-MSBRs with the UK’s existing renewable energy infrastructure to create a fully decarbonized energy system by the late 2030s.
The UK’s Decision to Immobilize and Dispose
The UK’s plan to immobilize and dispose of 140 metric tons of RGPu reflects a cautious approach to nuclear materials management. Immobilization involves incorporating plutonium into stable matrices, such as glass or ceramic, for the purpose of making it unsuitable for weapons use, never mind that it wasn’t suitable for such uses to begin with. This material will then be buried in deep geological repositories, isolating it from the biosphere for thousands of years. While this strategy was intended to address long-term security and environmental concerns, it comes at a steep cost—estimated at £2-3 billion—and provides no productive return on the investment. It also fails to achieve its intended benefit (see below).
This approach ignores the potential to recycle this plutonium into fuel, which could help address the UK’s energy challenges. To understand this missed opportunity, we’ll examine how this RGPu could have been utilized with both current and forthcoming reactor technologies to enable a completely carbon-free energy solution for the UK by the late 2030s. But first, let’s examine why the perceived benefit is bogus to begin with.
Misconceptions about RGPu and Proliferation Risk Mitigation
This decision by the UK was obviously inspired by the widely held but completely incorrect perception that RGPu derived from reprocessing fully spent nuclear fuel from commercial power reactors could fall into the wrong hands and be used to build nuclear bombs. This perception was created by India’s “Smiling Buddah” nuclear weapons test in 1974, which is still badly misunderstood by policymakers more than 50 years later. This a nuanced subject that warrants a separate substack post of its own, but I’ll briefly cover the basics here.
The widespread but incorrect perception is that India was able to make and detonate their “peaceful nuclear explosion” (they didn’t want to call it a bomb for PR reasons) from RGPu that came from reprocessed fully spent nuclear fuel waste. That simply isn’t true. It would never have been possible to make that bomb in 1974 (or today) from RGPu that came from reprocessing fully spent nuclear fuel waste.
It’s true that India’s 1974 “peaceful nuclear explosion” was made possible in part by re-purposing spent fuel reprocessing equipment, so there is a reasonable argument to be made that nations in possession of such equipment should safeguard against someone else trying to repeat what India did in 1974. But you simply can’t make a working bomb from RGPu recovered from fully spent nuclear fuel, and that’s not what India did in 1974 despite widespread misconceptions that they did.
India’s 1974 experiment involved manufacturing near-weapons grade plutonium by re-purposing a Canadian CIRRUS heavy-water research reactor as a plutonium production reactor. They had to put several bundles of fuel into that reactor and then operate the reactor for a much shorter amount of time than would normally be called for to fully consume the fuel. Only through very careful manufacture of numerous “short-burn” fuel bundles was India able to produce the nearly weapons-grade plutonium they needed for their “peaceful nuclear explosion”. It’s true that they re-purposed some spent fuel reprocessing equipment to extract the plutonium, but the only reason the bomb worked was that they were not working with the same kind of RGPu that the UK just decided to dispose of for no good reason.
There was a knee-jerk in global policy reaction to the Smiling Buddah test, and to this day, policymakers around the world incorrectly perceive the RGPu recovered from fully spent nuclear power reactor fuel to present the same proliferation risks as the near weapons-grade plutonium India produced for Smiling Buddah. That’s a myth, plain and simple, so the entire premise of policymakers’ desire to mitigate this entirely imagined proliferation risk is completely misguided. This includes the 140mt of RGPu the UK now irrationally aims to dispose at massive taxpayer expense.
The reasons that RGPu from fully-spent nuclear fuel waste simply cannot be used to make a bomb but RGPu from very short-burn fuel bundles could indeed be used to make near weapons-grade plutonium (what India did in 1974) are nuanced and will have to wait for a separate post on that subject at a future date. The point for now is that the RGPu that the UK is disposing is not useful for bomb-making.
MOX Fuel: An Abandoned Opportunity with Today’s Reactors
Mixed oxide (MOX) fuel combines RGPu with depleted uranium (U-238), allowing existing nuclear reactors to safely consume the plutonium while generating electricity. With 140 metric tons of RGPu, the UK could produce enough MOX fuel to supply its electricity needs for about six years, thanks to the energy derived from both the plutonium and the U-238 component. And that’s what the UK was using their RGPu stockpile for prior to this decision: Making MOX fuel. So they were on the right track, but now they literally just threw away about six years worth of electricity for no good reason.
Calculations from ChatGPT (unverified by the author):
Thermal Energy from RGPu Alone:
140 metric tons (140,000 kg) of RGPu would produce 140,000 MWd of thermal energy per kg, equivalent to 3.36 billion MWh.
Thermal Energy from U-238 Contribution:
In MOX fuel, roughly 50-60% of the energy comes from the U-238 component that is transmuted into plutonium-239 and subsequently fissioned.
Assuming 1.5x the energy from RGPu alone, total thermal energy becomes 3.36billion MWh×1.5=5.04billion MWh.:
Electric Energy from MOX:
With a thermal-to-electric conversion efficiency of 33%, the total electric energy produced would be 5.04billion MWh×0.33=1.6632billion MWh (1,663 TWh).
UK Electricity Consumption:
The UK’s annual electricity demand is ~280 TWh/year.
The energy from MOX fuel could supply the UK’s electricity needs for approximately six years (5.94 to be exact).
While MOX fuel represents a significant opportunity, this approach is limited by the high cost and inefficiencies of conventional reactors, which are not optimized to maximize plutonium utilization. Enter Copenhagen Atomics and their TS-MSBR technology—a game-changer for nuclear energy.
TS-MSBRs: A Thorium-Based Energy Future
Copenhagen Atomics, a Danish nuclear startup, is developing a modular molten salt reactor designed to operate on thorium fuel. Their TS-MSBRs require an initial “kickstarter” load of fissile material—such as RGPu—to begin the reactor’s operation. Once started, these reactors can transition to a sustainable thorium fuel cycle, producing electricity at unparalleled efficiency and minimal cost.
Using 140 mt of RGPu to Kickstart TS-MSBRs:
Initial Fuel Load:
Each reactor requires a 200 kg load of RGPu to start.
140 metric tons of RGPu could kickstart 700 TS-MSBRs.
Energy Potential:
Once operational, each reactor produces 100 MW of thermal energy.
700 reactors collectively generate 70,000 MW (70 GW) of thermal energy, or ~23 GW of electricity (at 33% thermal efficiency).
Thorium Fuel Cycle:
Thorium, costing ~$50/kg, can yield 22 GWh(t) per kg.
Each reactor consumes ~40 kg of thorium annually, translating to an annual thorium cost of ~$2,000 per reactor or $1.4 million for the entire fleet.
Energy Output:
The fleet produces 202.4 TWh/year of electricity, covering ~72% of the UK’s electricity demand indefinitely.
Economic Comparison: Immobilization vs. TS-MSBR Deployment
The following economic analysis was performed by ChatGPT 4o.
Immobilization and Disposal:
Upfront Cost: £2-3 billion (~$3.5 billion).
No ongoing revenue.
TS-MSBR Deployment:
Upfront Reactor Deployment Cost:
$10 million per reactor × 700 reactors = $7 billion.
Annual Operating Costs:
$5 million per reactor × 700 reactors = $3.5 billion/year.
Annual Fuel Cost:
$2,000 per reactor × 700 reactors = $1.4 million/year.
Annual Revenue:
Electricity price: $50/MWh.
202.4 TWh/year × $50/MWh = $10.12 billion/year.
Annual Net Revenue:
$10.12 billion - ($3.5 billion + $1.4 million) = $6.62 billion/year.
Long-Term Perspective:
Over 10 years, TS-MSBRs could generate $66.2 billion in net revenue while producing 2,024 TWh of electricity.
In contrast, immobilization incurs a one-time $3.5 billion cost with no future benefit.
Author’s corrections to ChatGPT Analysis
ChatGPT’s $7bn CAPEX figure appears to correctly assess the cost to manufacture the reactors, but doesn’t appear to include the steam turbines, electric generators, and other required powerplant components. I don’t know where ChatGPT got its $5mm per reactor per year estimate, but that figure is much higher than the company projects. So CAPEX is probably higher than ChatGPT thinks, but OPEX is probably much lower.
Copenhagen Atomics also proposes to own and operate its entire fleet and sell energy wholesale to its customers, so the actual CAPEX to the UK would be zero in that situation and presumably Copenhagen Atomics’ need to make a profit would mean that some of the potential profit anticipated by the above calculations would be shared with the company. But for sake of roughly understanding the magnitude of the policy error the UK government just made, I think the above calculations from ChatGPT provide a reasonable proxy showing how badly they just screwed up, for no apparent benefit other than a completely imagined perception that they’ve somehow reduced proliferation risks when they really haven’t.
A Complete Energy Solution for the UK
By combining the electricity from 700 TS-MSBRs (72% of UK demand) with the UK’s existing renewable energy infrastructure (wind, solar, and batteries), the country could achieve a fully decarbonized electricity system by the late 2030s. The total cost of electricity would drop dramatically due to the low operating costs of TS-MSBRs and renewables, ensuring affordable, clean energy for all. But they literally just decided to spend ~$3.5bn of taxpayer money to throw away the essential ingredient needed to enable this success story.
Lessons from India: A Strategic Vision
India’s three-stage nuclear program demonstrates a forward-thinking approach to utilizing RGPu. India has committed to reserving its RGPu for kickstarting thorium reactors, recognizing its strategic importance for achieving long-term energy independence. This stands in stark contrast to the UK’s decision to immobilize its plutonium, effectively discarding a resource that could transform its energy future.
India’s focus on thorium reactors is part of its broader strategy to harness its vast thorium reserves while reducing reliance on uranium imports. The UK could take inspiration from India’s strategic vision by leveraging its own RGPu stockpile to establish a thorium-based energy economy, ensuring energy security and sustainability for generations.
Conclusion
The UK’s decision to immobilize and dispose of its RGPu represents a significant lost opportunity to revolutionize its energy future. With technologies like MOX fuel and, more importantly, TS-MSBRs, this material could have been leveraged to meet national energy needs, reduce greenhouse gas emissions, and create substantial economic benefits. Policymakers should reconsider this decision and embrace the potential of advanced nuclear technology to power a cleaner, more prosperous future.
The decision UK policymakers just made was akin to removing several billion worth of Gold Bars from UK’s central bank reserves, then spending another few billion to have their Navy carry it half-way around the world to then dump those gold bars overboard to “safely dispose of them”, despite that they never posed any threat to anyone. That’s how absurd this decision truly was!