August 8, 2022

expert reaction to Ukraine’s Zaporizhzhia nuclear plant and media reports of shelling

A few journalists have asked us about the Zaporizhzhia nuclear plant, so here is a comment from Dr Mark Wenman and Professor Tom Scott in case useful.

Prof Tom Scott, Professor in Materials, Bristol University said:

“The primary risk is that the three radiation detectors that were knocked out means that the dry fuel store is not properly monitored.  Although it seems that no storage casks were damaged in the reported shelling it is possible that further shelling might crack or breach the concrete shielding around one or more casks meaning that gamma radiation shine could locally radiate out and present a hazard for any workers in the immediate area.  Because the monitors are inoperable it wouldn’t be immediately obvious if such an incident has occurred.  It would not trigger any substantial fire, nuclear explosions or airborne releases of material.

“There is talk of UN visits and possibly even the use of peacekeeping forces, but what is really needed, immediately, is some action from the UN.  Sitting, waiting, and watching from the side-lines is almost inviting an incident of some sort.

“Thankfully the actual nuclear plant at Zaporizhzhia is built like a fortress, so this is a mitigating factor, but every fortress will have its weak points and if damage is deliberately inflicted from inside the plant then a more substantive incident might conceivably unfold.

“It’s a very concerning situation and can’t be allowed to continue like this.”

Dr Mark Wenman, Reader in Nuclear Materials at Nuclear Energy Futures, Imperial College London, said:

“The VVER-1000 is a relatively modern and robust reactor design.  The reactor is unlike the Chernobyl style RBMK and is housed inside a heavily reinforced steel and concrete building that is designed to protect against natural disasters and or man-made incidence such as aircraft crashes or reactor accidents.  As such I do not believe there would be a high probably of a breach of the containment building even if it was accidently struck by an explosive shell and even less likely the reactor itself could be damaged by such.  This means the radioactive material is well protected.  Likewise the recently spent fuel is kept in a separate set of buildings that will be fairly robust concrete construction.  The fuel will be kept in these water pools known as ponds whilst it cools down.  Only freshly removed fuel will be significantly heat generating and as most of the reactors were shutdown in March I expect there is relatively little if any new spent fuel in the storage ponds since the war began.  The spent fuel that has been removed from the ponds is again stored in very robust steel and concrete containers that are designed to withstand very high energy impacts.  Although it may seem worrying, and any fighting on a nuclear site would be illegal according to international law, the likelihood of a serious nuclear release is still small.”

eg. https://www.bbc.co.uk/news/world-europe-62412429

Declared interests

Prof Tom Scott: “No conflicts of interest.”

Dr Mark Wenman: “No conflicts of interest to declare.”