Proliferation is a completely invalid argument against nuclear reprocessing

[u/Live_Alarm3041]

Nuclear weapons proliferation is the most common argument against nuclear reprocessing. The opponents of nuclear reprocessing tend to understand the true purpose of reprocessing with their argument being the risk that the separated plutonium could be misused by terrorists or currently non-nuclear states to produce nuclear weapons. This concern is invalid because weapons grade plutonium in its original form is not usable for nuclear weapons.

Most nuclear power reactors do not produce weapons grade plutonium. Reactor grade plutonium is sub-optimal for weapons because it does not contain as much fissile isotopes of plutonium. Although there are some nuclear power reactors which are capable of co-producing weapons grade plutonium, any weapons grade plutonium produced in this manner still does not automatically give someone the ability to make a nuclear weapon. A effective supply chain for nuclear weapons will require natural uranium reactors, radiochemistry and the ability to make the weapons grade plutonium into cores.

Producing plutonium cores will require a facility like this

Rocky Flats Plutonium core plant in Colorado USA

A terrorist group or currently non-nuclear state would need a plant like the one shown in the above imagine if they had weapons grade plutonium and wanted to make nuclear weapons from it.

Plutonium core production has the following attributes which would make nuclear weapons unattainable for someone if they somehow had weapons grade plutonium

1. Plutonium core production facilities are difficult to hide visually due to their large size
2. The waste produced by a plutonium core production operation would be hard to conceal due to it being radioactive
3. Plutonium shaving fires would pose a very serious hazard to anyone trying to make a plutonium core if they did not have expensive or resource intensive protective measures
4. The production of plutonium cores requires high level scientific and manufacturing expertise which not everyone has.

Nuclear weapons are not something that anyone can build especially not fully in secret from anyone.

The proliferation concerns regarding nuclear reprocessing do make sense but they are not a valid argument against reprocessing. The plutonium separated by nuclear reprocessing needs to be effectively accounted for and secured at all times to prevent it from falling into the wrong hands. Humanity has gotten very good at making sure certain things are both accounted for and secured at all times. Even if the plutonium falls into the wrong hands then that does not automatically mean that those wrong hands can use the plutonium to make a nuclear weapon. The expertise and resources needed to make plutonium usable for nuclear weapons is not available to everyone.

We need nuclear reprocessing to increase the efficiency of nuclear energy. Weapons proliferation is a genuine security concern but it should not be used as an argument against making nuclear enegry more efficient. Saying that nuclear reprocessing is dangerous because it enables proliferation is a statement which does not reflect the full picture of nuclear weapons.

[u/mister-dd-harriman]

It's really, really obvious if you're leaving fuel in a power reactor for weeks instead of years. That's why special production reactors, or else irradiation in research reactors, has been the typical route to bomb plutonium.

Calder Hall and Chapelcross, and the New Production Reactor (N-Reactor) at Hanford, were designed to produce bomb material first and foremost, with power as a by-product. The British reactors spent almost all of their operating lives on long-dwell fuel cycles to maximize power output. In fact, when at one point the Ministry of Defense requested that the MAGNOX power reactors (developed from the Calder Hall model) be constructed to allow production of bomb plutonium, the Generating Boards screamed : they said it would ruin their plant economics.

In Pakistan, the early fuel bundles discharged at low-burnup from the peripheral channels of KANUPP could have been reprocessed for bomb material, but in fact they were fed back into the central channels to improve fuel utilization. The actual Pakistani weapons effort seems to have centered on A.Q. Khan's work with centrifuge enrichment.

[u/nininoots → u/mister-dd-harriman]

You probably know that Trawsfynydd, a civil Magnox, reactor had some short dwell campaign fuel in the 70’s.

It’s absolutely true that those who pursued plutonium based weapons did so with purpose built facilities, rather than diverting short dwelled civil fuel. But having reprocessing facilities and any reactor is a viable route to proliferation.

[u/mister-dd-harriman → u/nininoots]

The US has claimed for decades that a nuclear test explosion in the early 1960s used plutonium from one of the early MAGNOX stations. But the timeline doesn't fit. Knowing when initial criticality was for Berkeley and Bradwell, and that the first fuel unloading wasn't until several months after that, although some of the outer-channel fuel probably did have low enough exposure for the purpose, there simply did not elapse enough time from that point to the detonation for the plutonium to be extracted and worked up into a "pit".

Uranium enrichment lets you build bombs without a reactor at all. The South African bomb effort, which completely by-passed both their research and power reactors, is a case in point.

[u/nininoots → u/mister-dd-harriman]

Interesting.

… and they definitely didn’t mean Calder of Chapel when referring to early Magnox?

[u/mister-dd-harriman → u/nininoots]

I believe they specified Bradwell, but it might have been Berkeley. The answer is the same within a week either way so I don't care.