Status of stress tests nuclear power plants in EU

Nuclear Monitor Issue: 
Patricia Lorenz, FoEE

In reaction to the Fukushima nuclear disaster the European Union decided to start a process to make sure whether European Union nuclear power plants are safe and events like in Japan can be excluded in Europe. Stress tests are defined as: 'Reassessment of safety margins of nuclear power plants in the light of the events at Fukushima: extreme natural events challenging the plant safety functions and leading to severe accidents".

In a three step process all countries were to check their plants based on the ENSREG (European Nuclear Safety Regulators Group) criteria catalogue, which again is based mostly on WENRA (Western European Nuclear Regulators' Association) criteria. While the first is a legitimate body of all 27 EU nuclear regulators, WENRA is a only the club of nuclear regulators.

A major issue is transparency, often announced by the regulators and EU officials, but this did not trickle down to the regulators ye. WENRA did conduct an almost unnoticed public consultation on the criteria, but did not even acknowledge receiving contributions from the public, like e.g. fairly elaborate contributions by FOEE (Friends of the Earth Europe) or Greenpeace and other groups. Nothing was taken up, no reason given why not. The first part of the stress tests was finished in time, when in August all operators handed in the reports on their plants. Based on these, the regulator reports were made and published on the ENSREG homepage. The differences in methods, approaches and simply the number of pages of the reports, of course are substantial.

One of the most important lessons learnt from Fukushima is that the probabilistic approach is not reliable; events unlikely to happen according to models and codes used during designing, licensing and safety checks, were obviously proven wrong. This is reflected in the ENSREG paper, urging states to look into extreme natural events, like seismicity and flooding and their combinations.

A good example for business as usual is the Romanian report. For assessing the seismic risk they apply very weak criteria which are contradicting international practice. For earthquakes it would be necessary to look into a earthquake which have a return period of at least 10 000 years and use this data to prove that an NPP resists an earthquake. Instead the Romanian reports sticks with the old data and uses the 1000 years return period chosen as design basis. The Czech report with 7 pages only stands out by being of exceptionally poor quality; however, there is an understanding they will come up with more complete one in the next few weeks. Similar though the situation in the Netherlands, where the regulator so far did not receive much more than the overview over what the Borssele operator will send until October 31.

The Slovak reports went into a lot more length, but the key questions are not answered:  In case of a station black-out, when no emergency diesel generators are available, having time is a great advantage to restore power for starting up cooling pumps for removing residual heat from the reactor and cooling the spent fuel pool. The report does not show clearly, how long it is possible to keep the reactor in a safe state during severe accident measures without power. There is no prove provided on how external impacts like airplane crashes, fires, explosions can be excluded as direct hazards for the reactor buildings /containment systems, which could lead to core melt.

What is to happen next: The EU Commission and ENSREG will produce the first progress report based on the individual country reports for the EU Council meeting on December 9. This phase is followed by a unique new procedure: EU peer review, when teams will evaluate the reports and are expected to even look at the nuclear power plant site. This is something very new in nuclear safety, which is the field of national competence only. The exact conduct of those peer review is of course an issue of discussions. Currently it seems that there will be 17 peer review teams. 14 of them will be vertical (looking into all aspects - one per country) and 3 will be horizontal (looking at all countries but only one issue: earthquakes, floods, loss of power and ultimate heat sink). Coordination will be done by a supervisory board.

There are concerns about the role of Mr. Petr Krs from SUJB to head the peer review process. This leading role given to the Czech regulator is met with a lot of distrust and criticism from NGO in this field. SUJB is acting openly pro-nuclear in the domestic energy debate and there is a lot of criticism about SUJB's role in the welding case around Temelin and the national stress report.

Two major Fukushima issues are not looked into properly: the emergency preparedness in case of severe accidents in European plants and the security issues. While it is obvious, that evacuations are not possible in densely populated European countries, the issue of security threats like armed attacks and targeted airline crashes are hidden under the thick cover of confidentiality of interior ministries, secret services and similar institutions. Along those lines a European Council working group was formed and started its meetings:  The first meeting of this working group under the Atomic Question Group (ATO), called Group Ad Hoc on Nuclear Security (GAHNS) took place before the summer break. It can be seen as a success, that all EU Member States participated in this group, including UK and Czech Republic. The European Commission participates as an observer. Some information from this group is expected to be taken up in the Commission Reports to the Council in December, April and June. The group has prepared a long list of issues and questions to be addressed.

The peer review will last until mid-2012. During this phase several evaluating events are expected to take place. On the one hand NGOs will demand seminars to be held in their countries, which will be encouraged by the EU Commission. The European Economic and Social Committee (EESC) is organizing a conference in December in Brussels and in the Summer of 2012 ANCLI (the National Association of Local Information Committees) and the EU Commission will co-organize a major meeting on stress-tests and Aarhus Convention. For further information also concerning the broader context please read the article already published earlier in this publication.

Source: Patricia Lorenz (with information provided by Jan Haverkamp –Greenpeace International- and independent nuclear safety expert Antonia Wenisch, who contributed first evaluations of some of the country reports)
Contact: Patricia Lorenz
Mail: patricia.lorenz[at]