Reprocessing and non-proliferation

Since its discovery plutonium has symbolized the Faustian bargain of nuclear fission: the unshackling of energy from the dirt and politics of fossil fuels, shackling it instead to the dirt and politics of nuclear weapons.

Plutonium itself does not exist naturally on earth in any practical quantity, but is spawned abundantly in nuclear reactors as a byproduct of the fission process: some uranium splits in half; some becomes plutonium.

This turns out to be quite fortuitous, since commercial nuclear power would have been much more difficult otherwise: between one-third and one-half of the energy from conventional power reactors (depending on the design) comes from plutonium self-generated in the fuel.

Maintaining the Faustian symmetry, plutonium’s discovery was also fortuitous to nuclear weaponry, being generally easier to acquire than weapons-grade uranium, and enabling more efficient, modern warheads.

But double-edged though this sword may be, it’s important not to lose sight of plutonium’s immense potential as an equalizer of wealth on this planet: we can do without nuclear war, but we can’t do without sustainable development (the end result is actually strikingly similar).

At stake is the potential extension of nuclear fission resources by a factor of 100, essentially making it limitless – or at least a healthy bridge to the next big solution.

And yes, the fact that our current usage of uranium is less than 1% efficient may surprise some, but these are the cards that nature dealt us – and it’s a long reach to the remaining 99%. Much more complex reactors are needed to convert the non-useful fraction of uranium to useful plutonium, followed by chemically reprocessing the irradiated fuel in order to turn this plutonium into new fuel.

Although the technology for both has existed for over half a century, getting this to work commercially and securely is a feat only now being widely pursued by governments and private companies, emboldened by the twin global crises of climate change and energy security.

Reprocessing – the chemical separation of plutonium (and other useful nuclides) from irradiated fuel – presents a challenge from both a technical and policy standpoint.

The far easier route is to avoid this recycling step altogether and dispose of used fuel in a geological repository – letting Nature protect future generations from the radioactive material the way she has done for billions of years.

This long-term repository route is being followed by several countries (the first movers including Finland, Sweden and Canada), but this practical step doesn’t take reprocessing off the table by any means.

Reprocessing’s policy challenge stems from proliferation concerns: any time you pry open the self-protecting tomb of irradiated nuclear fuel, extracted plutonium becomes intrinsically more attractive for nefarious purposes: this is unavoidable since it's been taken one further step towards weapons usefulness.

Is the process overall less proliferation resistant? This is a more complex question, which can’t be answered without analysis of the larger system.

Many advanced reprocessing technologies propose a measure of intrinsic protection by pulling out plutonium (and other useful nuclides) alongside non-useful nuclides – typically enabled by a reactor design that can run economically on such impure fuel mixtures.

Regardless of the intrinsic features however, safeguards will be needed.

The International Atomic Energy Agency has the capability to impose measures to objectively verify – to a global standard – that all plutonium remains where it was declared (and no undeclared plutonium is secretly created).

These safeguards underpin the global non-proliferation regime, supporting for over half a century every country’s inalienable right to pursue peaceful uses of nuclear energy under the Non-proliferation Treaty (NPT).

Today’s non-proliferation regime grew from a failed U.S. policy of nuclear secrecy immediately following WWII, as it became increasingly recognized that robust international safeguards drive sustainable development and not handouts in front of a barricaded barn door.

More complicated systems demand more complicated safeguards, but this can be mitigated immensely by working with technology developers well ahead of a first-build project, ensuring that safeguards are built efficiently into the system as much as possible.

This ‘safeguards by design’ approach is underway today, taking advantage also of synergies with measures already needed for safe operation and nuclear security (a so-called ‘3S’ approach).

In this light, the steps taken to ensure the safeguarded (and safe and secure) operation of advanced nuclear systems, if affordable and effective, become necessary enablers of historically unprecedented access to abundant energy for a world where most lack this – and where the minority that has enjoyed it to date has almost destroyed the world doing so.

The policy of secrecy returned in 1977 when President Carter famously banned reprocessing in the U.S. out of proliferation concerns. President Reagan subsequently lifted the ban four years later, and although U.S. policy then wavered back and forth through subsequent political regimes, reprocessing was never banned outright again.

Going forward, the important question of nuclear reprocessing will be a matter for objective technical and sociopolitical assessment that must include the capabilities of international safeguards – which are considerable.

Any technology with the potential to extract 100 times the energy from a waste material at least deserves this.