20 Years of Commitment to Continuous Improvement of Nuclear Safety

Posted May 17, 2019, 11:49 a.m.

This year, WENRA is celebrating its 20 years anniversary. Twenty years after its foundation as an independent “club” of the Heads of the national nuclear safety authorities of Europe, WENRA is a broadly recognized reference and an important player in the global field of nuclear safety. While WENRA has just developed and adopted its new strategy for the future, the celebration of the 20th anniversary is also a reason to look back:

History of WENRA

In the 1990s, the heads of the regulatory bodies of a number of European countries came together for one informal meeting only. While acknowledging the importance that nuclear safety should remain a national responsibility, they also recognized a strong need for more international cooperation. An idea formed to start a group to work on harmonizing regulations and requirements on the European level. In February 1999 WENRA was founded.
Its ten founding members were the heads of the nuclear regulatory authorities of the EU countries with nuclear power plants and Switzerland. Since then, WENRA has had five chairpersons from different member states, namely France, Sweden, the Czech Republic, Finland, and currently Switzerland.

One of WENRA’s most important tasks was to provide the European Commission with independent assessments of nuclear safety in eastern European countries applying to join the European Union at the time. As the European Union expanded and included more and more countries with their own nuclear programmes, so too did WENRA. From the initial ten members, WENRA has grown to its current 18 members and 13 observers. Switzerland and Ukraine are the only WENRA members that are not in the European Union. The Russian Federation, Japan and Canada, all with a large fleet of nuclear reactors, have the status of observers. This means on the one hand that WENRA has access to knowledge of and experience with reactor designs from all around the world and on the other hand it can influence WENRA partners from outside Europe to consider adopting its high standards of nuclear safety. Several EU-countries without nuclear power programmes are also WENRA observers. 

In line with its general aim of improving nuclear safety, WENRA pursues several objectives. The first is building and maintaining a network of chief nuclear safety regulators in Europe. WENRA also strives to promote exchange of experience and learning from each other’s best practices and to develop a harmonized approach to nuclear safety and regulation, in particular within the European Union. Another broad objective is to discuss and, where appropriate, give opinions on significant safety and regulatory issues.

From the very beginning, WENRA has committed itself to continuously improving nuclear safety in all its member countries. To make this goal achievable in practice, a common and harmonized approach to nuclear safety had to be chosen. The development of common Safety Reference Levels based on IAEA safety standards as well as good practices of the members are laying the basis for this. 

WENRA Safety Reference Levels

Soon after WENRA was founded, two permanent working groups were established to harmonize safety approaches between countries in Europe. These are the Reactor Harmonization Working Group (RHWG) and the Working Group on Waste and Decommission (WGWD. The mandate of the working groups is to analyse the current situation as well as countries’ safety approaches, compare individual national regulatory approaches with IAEA safety standards, identify any deviations from these standards and propose a way forward to eliminate them. The proposals are expected to be based on best practices, implementing the most stringent requirements for existing power reactors and nuclear waste facilities. The most important part of the work of these two groups today is drawing up Safety Reference Levels. These Safety Reference Levels are a living document. They are revised whenever new knowledge or experiences become available.

Besides the two permanent working groups, ad-hoc working groups are set up to address current and specific issues. WENRA currently has one ad-hoc working group, which is working on formulating appropriate reference levels for research reactors and identifying which Safety Reference Levels for existing reactors are applicable to research reactors with a high thermal output. In addition, WENRA has a task force working on strengthening the interface between nuclear safety and nuclear security in its member states.

The Safety Reference Levels have been established to ensure greater harmonization within WENRA countries and to raise the level of nuclear safety in Europe by implementing them in national regulatory frameworks. While the RHWG works on Safety Reference Levels for Existing Reactors, the WGWD works on Safety Reference Levels for Decommissioning, Storage of Waste and Spent Fuel and Disposal. These Safety Reference Levels do not cover legal and technical details, but they reflect practices WENRA countries are expected to implement. The documents are formulated to be brief, high-level and significant.

RHWG published the first set of Safety Reference Levels for existing nuclear power plants in 2006 and revised them in 2007, 2008 and 2014. The emphasis of the Safety Reference Levels has been on nuclear safety, primarily focussing on safety of the reactor core and spent fuel. The areas and issues addressed have been selected to cover important aspects of nuclear safety where major differences between WENRA countries might be expected. The documents are not intended to cover every aspect that might have an impact on nuclear safety or to provide a platform for determining the overall level of nuclear safety in operating nuclear power plants. The Safety Reference Levels should always be considered as a whole set, since some of the issues covered are interdependent.

To keep the Safety Reference Levels up-to-date, WENRA commits itself to regular revisions. The most prominent incident prompting a revision was the Fukushima Dai‑ichi nuclear accident in 2011. Following the accident, RHWG updated the Safety Reference Levels and WENRA approved their publication in September 2014. The updated Safety Reference Levels now take into account the lessons learned from the accident, including the insights gained from the European stress tests. As a result, the Reference Levels now also cover the issue of natural hazards and significant changes were made to many of the existing documents. 101 Safety Reference Levels were either revised or newly introduced. The 2014 version of the Safety Reference Levels covers 19 issues and includes a total of 342 Reference Levels. To make sure that the new and updated Safety Reference Levels have been adequately implemented in the national regulatory frameworks, RHWG conducted a peer review process with criteria agreed by WENRA. This peer review consisted of a self-assessment by each member against the content of the 101 revised or new Safety Reference Levels, followed by a peer review within the RHWG.

The process of regulatory harmonization for waste and spent fuel storage started in 2002 and was completed in April 2014 with the publication of the Waste and Spent Fuel Storage Report (v2.2). The WGWD completed its report on Decommissioning in April 2015 with the finalisation of the Decommissioning Safety Reference Levels Report (v2.2). The report on Radioactive Waste Disposal Facilities Safety Reference Levels was published in December 2014, defining a set of 108 Safety Reference Levels applicable to waste disposal regulations.

In September 2017, WENRA published the WGWD Umbrella Document: Interfaces and Interdependencies. This report highlights the connections between the different WGWD reports. It focuses on aspects that are not covered by the Safety Reference Levels and provides guidance by referring to internationally accepted requirements and recommendations.

WENRA approved the report Radioactive Waste Treatment and Conditioning Safety Reference Levels (v1.1) in 2018. This report covers safety relevant issues of waste processing from small mobile equipment up to large stationary installations and facilities. Since this document addresses the process of generating the final waste package, to be disposed of in a repository, there are strong links to both the disposal and the storage reports.

Guidance beyond Safety Reference Levels

In addition to developing safety standards in the form of the Safety Reference Levels, WENRA also issues reports and recommendations on current, specific issues. For example, a recent recommendation referred to macro-segregation anomalies found in French reactors. The latest RHWG publication was the “Report on Regulatory Aspects of Passive Systems” and the latest WGWD publication was the “Report on Radioactive Waste Treatment and Conditioning SRL”.

Furthermore, WENRA lends the European Union its technical expertise. WENRA developed the technical specifications for the National Assessment Reports for the European Union’s first Topical Peer Review on the issue of Aging Management and wrote a guidance document on Article 8a of the European Union’s Nuclear Safety Directive. This Article requires “timely implementation of reasonably practicable safety improvements to existing nuclear installations” by the member states of the EU.

WENRA’s Future and Challenges

To cope with the changing landscape of the nuclear world, WENRA has developed and adopted   a new strategy based on the vision “WENRA is the independent association of European national nuclear regulators recognised for establishing, implementing, and disseminating harmonized model levels of nuclear safety.”

One goal of the new strategy is to increase WENRA’s available knowledge pool. To achieve this, a third membership status was created, that of an associated member. Associated members will be able to participate in working group meetings, provide their input during plenaries and will be eligible to chair a working group. In turn it is expected that associated members consider implementing the Safety Reference Levels and enacting proposals agreed by WENRA. Decision-making will nevertheless remain exclusive to full members.


Summary and Outlook

Over the last 20 years, WENRA has achieved a high level of harmonization of nuclear safety in its member states. WENRA continuously promotes a broad understanding of safety by taking a holistic view on challenges, and suggests actions needed to protect people and the environment and to avoid a nuclear accident. The Safety Reference Levels are being revised regularly and on short notice, should new knowledge warrant it. WENRA is working on identifying applicable Safety Reference Levels for research reactors and on promoting greater integration between safety and security.

WENRA will continue to strive for the common goal of harmonisation and continuous improvement of nuclear safety to prevent severe accidents in nuclear power plants. It will continue to offer its technical expertise to the European Union, especially in the future Topical Peer Reviews, which will be carried out every 6 years.

WENRA’s will continue strengthening and building on its role as an important player in nuclear safety, in Europe and beyond.

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