Stress tests

New study on Updated National Action Plans

The study "Four Years After Fukushima: Are Nuclear Power Plants Safer? Critical Review of the Updated National Action Plans (NAcP) of the EU Stress Tests on Nuclear Power Plants in Bulgaria, Czech Republic, Hungary, Romania" was written in 2015 by Patricia Lorenz and Oda Becker, and was financed by the grassroots foundation.

Stress test factsheets

In 2015, for four countries (Bulgaria, Czech Republic, Hungary and Romania) fact sheets on stress tests have been produced to give a quick background on the current status.

Brochure "Stress Tests & Lifetime Extension"

In 2013, Joint Project together with Oda Becker and Patricia Lorenz produced a "Critical Review of EU Stress Tests and Life Time Extension Plans in Bulgaria, Czech Republic, Hungary and Ukraine." Topics covered are: an overview on PLEX, an overview on the National Action Plans of Stress Tests, and country-specific reviews.

Brochure "Stress Tests & Vulnerability Assessment - Recommendations and Experience of the Joint Project group"

This brochure from 2012 contains a critical evaluation of the stress tests. It can be downloaded here.

  • There is no definition how big this "higher safety margin” have to be – so there is no way to determine whether a NPP passes or fails a test.
  • The design basis of EU NPPs differs considerably – e.g. NPPs are designed to withstand 500 to 10.000-year events depending on the country they are built in. So there are no consistent reference values – the safety margins therefore are based on completely different basis values.
  • That's why the comparison of the reports is not possible - the reports only have to follow a common structure.

Letter to the EC council

In December 2011, the following letter was sent to the EU Council and (in adapted form) to the national regulators of the Joint Project countries.

Appeal to Heads of States and nuclear regulators on stress tests, on the occasion of the EU Council December 9th 2011
"At this summit, the EU Commission will present a progress report on nuclear power plant (NPP) stress tests, which were initiated in response to the Fukushima nuclear disaster.

We are a group of environmental NGOs based in Central and Eastern Europe who have been following developments in the nuclear field, both in our countries and on a European level. We have been in contact with national nuclear regulators since the beginning of the implementation of stress testing in June 2011, and have received unsatisfactory answers to our questions.

We are very worried about the status of the stress tests. The promise of strict safety assessments in the aftermath of the Japanese accident seems to have faded into a business as usual safety assessment exercise. Instead, a clear end to nuclear safety regime with “unthinkable” scenarios, probabilistic assessment and high in-transparency is inevitable.

Having read the interim reports submitted by EU member states, we would like to point out that:
  • Most countries are not able to handle a major accident in one of their NPPs. Necessary measures for emergency preparedness are not in place. This question has to be discussed, clear plans need to be prepared by each country, and must be discussed with the public.
  • It is not enough to announce, as the Commission interim report does, that there will be international cooperation. Countries with nuclear plants in operation need to be able to protect their own and neighbouring countries´ citizens.
  • The stress tests cannot be seen as the final say on safety; important issues like ageing NPPs and aeroplane crashes are not taken into account.
  • The regulators in most countries see themselves as promoters and defenders of nuclear energy, an attitude which seriously endangers safety. Fukushima is just one of many examples.

Based on what we consider very urgent matters to be tackled with regards to the progress of stress tests, we hereby demand:

  • Full transparency: we ask member states to open their nuclear safety regulation to public scrutiny – both the stress test results and more generally – in order to prevent catastrophes like the one in Japan in March 2011.
  • Establish full transparency of nuclear regulators.
  • The highest standards must be applied in the tests. It is not enough to assess that safety margins are “differing” across Europe. Highest standards also need to be applied for the methods, for example on earthquake return periods. The highest standards need to be demanded right away for all reactors in operation in the EU and not, as the Commission report suggests, “best practices for new nuclear power plants to be built in the EU”. We are against any new nuclear plants in the EU, because we consider the risks are too high.
  • The new safety legislation should not only be discussed with “national regulators, nuclear regulators and …ETSON” who have been responsible for nuclear safety over the past decades, but should also include independent experts, NGOs and civil society. The same approach needs to be adopted when improving nuclear safety governance, to ensure it is taken seriously.
  • Open discussions and workshops for interested public at national and international levels on stress tests.

We ask you to clearly implement far more stringent methods for testing nuclear safety, with clear sanctions
for non-fulfilment. It is not acceptable to postpone measures which we all know to be necessary today. The parallels with the Japanese regulatory failure to take warnings concerning tsunami and seismic risks seriously are highly concerning.

Finally, we do not view the stress testing as a means of proving that EU nuclear plants are safe, but rather to assess their relative risks and decide which ones need to go offline first and which later.. None of this negates the fact that nuclear power is not safe and not sustainable. However, whilst nuclear power plants continue to operate they must be held to the highest safety standards.

Yours sincerely,

Patricia Lorenz

Friends of the Earth Europe
Rue d'Edimbourg 26, B-1050 Brussels
patricia.lorenz@foeeurope.org

Foundation for Environment and Agriculture, Mr. Borislav Sandov
2 Vassil Levski str., 5940 Nikopol, Bulgaria
agroecofund@mail.bg

Za Zemiata, Mr. Todor Todorov
Yanko Sakazov Bul 50, fl. 3, ap. 17, Sofia, Bulgaria
t.todorov@zazemiata.org

South Bohemian Mothers, Mrs. Monika Wittingerová
Nová 12, 370 01 České Budějovice
monika.wittingerova@centrum.cz

Calla, Edvard Sequens
Fráni Šrámka 35, 370 01 České Budějovice
edvard.sequens@calla.cz

Energy Club, Mr. András Perger
Szerb Utca 17 – 19, 1146 Budapest, Hungary
Fax: +36-1-411 35153
perger@energiaklub.hu

Terra Mileniul III, Ms. Ioana Ciuta
7 Armand Calinescu street, 5th floor, app. 20, sector 2, 021011, Bucharest
ioana.ciuta@terraiii.ngo.ro

Global 2000, Mr. Reinhard Uhrig
Neustiftg. 36, 1070 Vienna, Austria
reinhard.uhrig@global2000.at"

Workshop 2011

In the Joint Project workshop in Nov. 2011 stress tests were the main topic.
The following presentations were given:
  • Presentation of Toni Wenisch on Stress Test Interim Reports (pdf, 285 KB)
  • Presentation Roman Lahodynsky on Seismicity and Nuclear Power (pdf, 15,3 MB)
  • Presentation Reinhard Uhrig Global 2000: European Citizens’ Initiative on safe & clean energy in Europe (pdf, 1,5 MB)

Questions to nuclear regulators

In this context in June 2011 several questions have been asked to the nuclear regulators of Bulgaria, Czech Republic, Slovakia and Romania:

  1. Which new scenarios which were excluded until now but after Fukushima proved to be realistic, do you ask the operator to assess? Please give us data on the new demands concerning natural disasters (flooding, extreme cold, extreme heat, snow, ice, storms, tornados, heavy rain and other extreme natural conditions.
  2. Aircraft crash: Will you demand a deterministic assessment of an aircraft crash? Which criteria will the plant have to prove to withstand?
  3. Will the seismic design basis be re-evaluated, which we consider crucial?
  4. How long is the plant able to control shut-down and cooling of the reactor and the spent fuel storage pool without external support if ultimate heat sink and power supply are not available due to external impact?
  5. Which are the responsible authorities in our country to take care of the part “terrorist attacks”?
  6. How will the public be informed about the conduct and the outcome of the tests?
  7. Will there be a seminar/workshop for NGO and independent experts while the stress tests are being conducted, e.g. in late August or September to discuss the results?

Stress Tests overview

In March 2011, the European Council (following an extraordinary meeting held on March 24/25) concluded that in the light of the Fukushima accident in Japan, the safety of all EU nuclear plants should be reviewed based on a comprehensive and transparent risk assessment (stress test).

ENSREG and the European Commission were invited to develop the scope and modalities of these tests in a coordinated framework with involvement of member states, making use of available expertise, like e.g. WENRA (network of nuclear Regulators). WENRA started working on the scope and methodology – the final WENRA proposal on scope/modalities for the stress tests was submitted to ENSREG May 7, 2011. On May 25, 2011 ENSREG published the scope and modalities for the risk and safety assessments of EU nuclear power plants (NPPs). The document determined the concept, methodology and time schedule.

It is important to understand that the stress test could not take into account all key safety issues such as the capability to prevent accidents - mainly due to lack of time, the acutal scope of the stress tests could not comply with the orginal idea of the European Council to provide a comprehensive and transparent risk and safety assessment.

The stress tests are defined as a targeted reassessment of the safety margins of nuclear power plants developed by ENSREG, including the European Commission, in the light of the events which occurred at Fukuhshima Daiichi.
This means that their aim is to assess whether the safety margins which were used in the licensing of nuclear power plants were sufficient to cover unexpected events. The reason behind that is that an important lesson to be drawn from the accident in Fukushima is that e.g. two natural disasters can hit at the same time and leave the NPP without any electrical power supply.

More information:

The general information our site provides is based on information from these sources.
A critical evaluation of the stress tests is available under the section "Problems of the Stress Tests" and the brochure "Stress Tests & Vulnerability Assessment - Recommendations and Experience of the Joint Project group" (see download section of this homepage).

Content

The reassessment of the safety margins of NPPs consists of:
  • an evaluation of the response of a nuclear power plant when facing different extreme situations (in these extreme situations sequential loss of the lines of defence is assumed in a deterministic approach, the probability of this loss is not taken into account).
  • a verification of the preventive/mitigative measures following a defence-in-depth logic: initiating events, consequential loss of safety functions, severe accident management.

The response of the NPP on the extreme situations including the effectiveness of the preventive measures and possible weak points are pointed out for each of the considered extreme situations.

Events covered

As risks due to security threats are not part of the mandate of ENSREG a two-track process has been developed.

Safety track:

The safety track covers extraordinary triggering events potentially leading to multiple loss of safety functions requiring severe accident management. Examples for such events are: earthquakes, floods, extreme cold, extreme heat, snow, ice, storms, tornados and heavy rain and consequences of other initiating events (e.g. transport accidents, such as airplane crashes).

The specifications of these assessments can be found here:
http://www.ensreg.eu/sites/default/files/EU%20Stress%20tests%20specifications_1.pdf

The technical scope of the stress tests has been defined considering the events that occurred in Fukushima, therefore the focus will be placed on the following initiating events:
  • Earthquakes
  • Floods

Consequences of loss of safety functions from any initiating event conceivable at the plant site are considered. Flooding will be included regardless of its origin.

Severe accident management issues are covered

The following information has to be given by the operator:
  • Design basis of the plant and conformance to design requirements
  • Robustness of the NPP beyond its design basis: available design margins, redundancy, physical separation etc. – in other words: are the margins which were used in the design basis large enough to cover unexpected events – like e.g. more than one initiating event occurring at the same time?
  • Potential modifications to improve the level of defence in depth

Security track:

Member states would not be convinced to discuss security (mainly terror attacks) like the safety issues; so the so called second track was invented. The first report of this group (GAHNS) produced no results, main topic seems to be confidentiality. The group consists of
anti-terrorism experts and officials of ministries for national security, interior ministries and intelligence services. Reason: These concerns are issues of national security and not part of the ENSREG mandate. Measures taken to counter terroristic acts cannot be made public.

Earthquakes

The technical scope of the safety track on earthquake includes (among other) the following points:
  • Design basis: Methodology to evaluate the design basis earthquake (DBE), adequacy of the DBE, provisions to protect the plant against the DBE, plant compliance with its current licensing basis
  • Evaluation of the margins: earthquake severity above which loss of safety functions becomes unavoidable, weak points; is this earthquake physically possible in the NPP region?
  • Provisions to increase robustness

Course of actions

Timeline

  • In March 2011, the European Council (following an extraordinary meeting held between March 24 and March 25) concluded that in the light of the Fukushima accident in Japan, the safety of all EU nuclear plants should be reviewed based on a comprehensive and transparent risk assessment (stress test). ENSREG and the European Commission were invited to develop the scope and modalities of these tests in a coordinated framework in the light of lessons learned from the accident in Japan with the full involvement of Member States, making use of available expertise, e.g. WENRA (network of nuclear Regulators). WENRA started working on the scope and methodology at its spring meeting, the final WENRA proposal on scope/modalities for the stress tests was submitted to ENSREG May 7, 2011.
  • Scope/modalities: On May 13, 2011 ENSREG published the scope and modalities for the risk and safety assessments of EU nuclear power plants (NPPs). The document determines the concept, methodology and time schedule.
  • National progress reports: According to Annex I of the “Declaration of ENSREG” national regulators had to initiate the process by sending requirements to the licensees (operators) on June 1, 2011, at the latest. Licensees had to provide a progress report to their regulators by August 15, 2011. This report had to be reviewed by regulators until September 15, 2011.
  • Under the leadership of ENSREG, requirements on content and structure of the reports and the peer reviews were developed. The requirements were agreed at a meeting on October 11, 2011.
  • The European Commission (supported by ENSREG) presented a progress report to the European Council for the meeting scheduled on December 9, 2011. This Interim report was published on November 24, 2011
  • Final national reports: The final licensee reports had to be delivered to the national authority on October 31, 2011, and the national report had to be delivered to ENSREG on December 31, 2011 by the national regulatory authority.
  • The peer review process was finished by the end of April 2012. The peer review was completed with a main report that includes final conclusions and recommendations at European level regarding the three topical parts and 17 country reports including country-specific conclusions and recommendations.
  • A consolidated report will be presented to the European Council by the European Commission for the meeting scheduled for June 2012.
  • The European Commission presented the ENSREG report in June 2012 to the European Council.
  • The EU Commission did not see the Council mandate for stress tests fulfilled and demanded further testing; six additional plant visits were undertaken, those follow-up reports were published in late October 2012.
  • In October 2012 ENSREG published a compilation of peer review recommendations and suggestions to assist the review of national action plans by national regulators.
  • To implement the stress tests findings, an ENSREG action plan is being developed (Dec. 2012) to track implementation of the recommendations. As part of this action plan each national regulator will generate a country-specific action plan. I

Phase 1 and 2: National reports of licensees and national regulators

  • National progress reports: According to Annex I of the “Declaration of ENSREG” national regulators had to initiate the process by sending requirements to the licensees (operators) on June 1, 2011, at the latest. Licensees had to provide a progress report to their regulators by August 15, 2011. This report had to be reviewed by regulators until September 15, 2011.
  • Final national reports: The final licensee reports had to be delivered to the national authority on October 31, 2011, and the national report had to be delivered to ENSREG on December 31, 2011 by the national regulatory authority.

The reports are available under:
http://www.ensreg.eu/documents - reports

Phase 3: Peer Reviews

Phases/Content

During the peer review, teams reviewed the fourteen national reports of EU Member States that are operating nuclear power plants – plus Lithuania - and of those neighbouring countries that have accepted to be part of the process (Ukraine, Switzerland, Lithuania).

The technical scope of the peer reviews comprised:
  • Compliance of the national reports to the stress test specifications
  • Safety improvements should be highlighted
  • Suitable standard/best practices of margins to hazard and fault conditions
The peer review process comprised
  1. horizontal/topical reviews as well as
  2. vertical/country peer reviews
  3. As the final step, an ENSREG Summary Report prepared under supervision of peer review Board will be issued..

The Topical Reviews
were looking at all of the countries’ contributions on that topic.

Three Topical Review teams work in parallel, each on one of the following topics:

  1. Earthquake, flooding and other external events
  2. Loss of power, loss of UHS and combination of loss of power + loss of UHS
  3. Severe accident management issues
At the end of the Topical Review phase the teams:
  • issued a working document that summarizes the overall conclusions of each Topical Review
  • draft preliminary Country Reports (which should provide sound conclusions on national reports and make preliminary recommendations to the countries).

The Country Reviews
The results of Topical Reviews fed the Country Reviews with inputs, the Country Reviews provided an opportunity for follow-up discussions on the relevant issues.

Summary Report
The Peer review was completed with a main report that includes final conclusions and recommendations at European level regarding the three topical parts and 17 country reports including country-specific conclusions and recommendations. The report was approved and published by ENSREG on April 26, 2012.
The European Commission presented the ENSREG report in June 2012 to the European Council.
The EU Commission did not see the Council mandate for stress tests fulfilled and demanded further testing; six additional plant visits were undertaken, those follow-up reports were published in late October 2012.

Phase 4: Action Plans

To implement the stress tests findings, an ENSREG action plan was developed to track implementation of the recommendations. As part of this action plan each national regulator generated a country-specific action plan. In October 2012 ENSREG published a compilation of Peer review recommendations and suggestions to assist the review of national action plans by national regulators. Also in October 2012, the European Commission published a “technical summary on the implementation of comprehensive risk and safety assessments of nuclear power plants in the European Union”. All reports, including the licensee reports have been made available on the ENSREG website.

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