Adam Rajewski from the Warsaw University of Technology comments on the alarmist report drafted for Germany’s Green Party that warns against a nuclear disaster in a Polish NPP whose opening is planned for 2033. “Even the best prediction model yields wrong results if the entry data are wrong,” the scientists concludes.
Two days ago the German media  (followed by Polish journalists) sounded the alarm bells claiming that a breakdown in Poland’s future nuclear power plant may pose a risk even to areas close to Berlin and Hamburg, which are about 400 km away from the planned NPP (the articles said 450 km, in reality it is less than 400 km to Berlin from either of the planned locations, but let’s not be petty).
The articles quoted an analysis written by Swiss specialists, and were adorned with suggestive illustrations that showed how a radioactive cloud from the area of Poland’s Żarnowiec would travel to Berlin. The scale of the event indicated that the residents of the Berlin area may be locally exposed to radiation doses exceeding 20 mSv, a value that was the criterion (per year) to evacuate the residents near Fukushima. Unfortunately, in none of the articles links to the source material were included, which meant one could only guess what the original report said. However, one could expect it was very serious. The reason is simple: 20 mSv so far away from the NPP means the disaster would be a lot more serious than the events in Chernobyl and Fukushima (even combined).
In Chernobyl, where the worst possible turn of events occurred – an inside explosion of a working reactor that did not have any so-called safety casing around it – the Gomel District, which is within a 200 km radius from the power plant was at the biggest risk of radiation. The doses in that area did not exceed 4 mSv in the first year (and 10 mSv in total) . Whereas in Fukushima, the safety casings were installed (albeit old and relatively worn out), but as many as three reactors were damaged. In that case doses over 20 mSv did not exceed a 30 km radius from the NPP in the “worst case scenario”.
So, what happened?
If one were to judge the report solely on the basis of the press articles, one would have to conclude that what happened was something that scientists sometimes jokingly refer to as GIGO ( Garbage In – Garbage Out), which means that even the best predictive modeling yields wrong results if the entry data are wrong. In this specific example, the authors did use a correct model for measuring the spread of contamination, but entered excessive data on the release of radioactive material. The excessive release will obviously spread further than a more realistic one, which paves the way for exaggerated impact. Even though the articles in German press did not include links to the report, it can be found on the internet . Maciej Lipka from the National Centre for Nuclear Research analyzed the report for the Energetyka 24 portal, and I recommend his review to those who are interested in reading a more specialized approach to the topic . In this article I will only mention the general conclusions.
First, the GIGO suspicions were justified. The authors of the report assumed that a disaster at a hypothetical NPP in Poland would cause an incredibly huge release of radioactive material. But they did not explain how that would happen, instead they just stated that the “study takes into account the AP1000 source term detailed by Shollyet al.(2014, 31-32) since it matches the severity of a major nuclear accident”. Maciej Lipka did some digging and analyzed where the source publication took these numbers from.
In a nutshell, the authors of the report did use the data in the analysis done for the United States Nuclear Regulatory Commission for the AP1000 reactor (which may indeed be installed in the Polish NPP), but the data did not describe a possible scenario of a disaster, but a reference case that is used to assess the efficiency of applied protections. Specifically, the reference case is based on the assumption that there is no containment structure (the heavy, concrete building, which is installed over the reactor on which it is “safe” to crash a plane). In other words, the report answers the question of what would happen if we took the reactor outside of the bunker and then blew it up.
With such an assumption, we will obviously reach numbers that exceed the Chernobyl disaster (where there was no proper containment structure, but some kind of protection was indeed present). Once we enter the data acquired in such a way into any study model that predicts exposure after a nuclear disaster (there are a few), we can get very excited about the doses in various areas (by the way, the media published a selected case out of 1096 variants, where the contaminated cloud conveniently flew over Berlin, and where it rained in the most fitting place). This approach could only be compared to performing a crash test of a Fiat 126p (a tiny passenger car that is no longer in production – transl.) which hits a concrete wall at 300 km/h. Of course from the point of view of the mechanics of calculations one could calculate the results of such an experiment and they would be correct. However, this does not mean we should get excited about the result.
The truth is less exciting. Nuclear power plants, even in such extreme cases as Fukushima (an old facility struck by a huge natural disaster), are unable to put the population at risk of significant nuclear radiation (by the way, there are no reasons to believe that the 20 mSv is a significant dose, but in radiological protection we follow the rule that doses have to be minimized just in case). A huge majority of even serious breakdowns (from the point of view of regulations) in nuclear power plants cannot put at risk even their staff (and even if, radiation is not on the table). However, such news is not very ‘clickable’ – “nothing happened” would not be a very popular headline.
To sum up, it is also worth mentioning that the report  has a misleading title. It says the paper is an “Analysis of Transboundary Environmental Impacts” for an NPP in Poland. However, in reality the report analyzes how contamination would spread, and the authors did not assess the risk of such a contamination occuring.
 Gutachter warnen vor polnischen AKW-Plänen. Die Zeit, 26 January 2021 [https://www.zeit.de/…/atomkraft-polen-gutachten-gefahr…]
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 Maciej Lipka, Skażeni manipulacją. Raport Zielonych wymierzony w polski atom jest skrajnie nierzetelny [ANALIZA] [Contaminated with manipulation. The Green’s report targeting Poland’s nuclear power is extremely unreliable – ANALYSIS]. Energetyka24, 28.01.2021. [https://www.energetyka24.com/skazeni-manipulacja-raport…]