Belgian safety strategy for radioactive waste surface disposal facility found to be "credible and robust"

The OECD Nuclear Energy Agency (NEA) has just presented to the Belgian authorities the outcome of an international peer review on "Key aspects of the safety case for a radioactive waste surface disposal facility in Belgium". The review examines the credibility and robustness of the long-term safety strategy and the long-term safety assessment documented in the draft safety case being prepared by the national radioactive waste management agency, ONDRAF/NIRAS. The draft safety case is being prepared for a license application for the construction and operation of a surface disposal facility for short-lived, low- and intermediate-level radioactive waste in the municipality of Dessel.

The review provides the Belgian authorities, the Belgian public and relevant organisations an international view on the maturity of ONDRAF/NIRAS's waste disposal programme and its safety approach vis-à-vis international best practices and recommendations.

Key findings

The international peer review team, consisting of seven international specialists, has concluded the following:

• From an international perspective, ONDRAF/NIRAS's long-term safety strategy and safety assessment are, in the main, credible and robust, with sufficient active and passive elements to support long-term safety. The strategy accounts for defence-in-depth, optimisation of the system design and passive safety principles. The long-term safety strategy follows international guidelines, recommendations and best practices.
• The proposed design of the disposal system takes into account the long-term safety strategy and is appropriate for the provisional radionuclide inventory as well as the characteristics of the geological environment at Dessel. The disposal concept and the technical design of the facility are adequately described; the safety functions of the various repository components are also clearly identified to allow long-term safety assessment to be carried out. Demonstration trials have improved the system design and confirmed the feasibility of construction of various system components.
• The iterative approach for long-term safety assessment used by ONDRAF/NIRAS follows international practices and is sound. A comprehensive interpretation of the assessment results was not performed in this review as some of the analyses were only presented near the end of the review process. The current safety assessment analyses show that ONDRAF/NIRAS has considered a large number of scenarios and assessment cases that have taken into account the design of the disposal system, the waste types and the environment. The set of scenarios is, in principle, adequate. Recommendations for improvements have been provided in the final report.
• ONDRAF/NIRAS's scientific knowledge and technical bases in relation to concrete and other engineered barriers are state-of-the-art and suitably documented and utilised. Technical limitations have been identified and are being evaluated in the current and future R&D programme.

Background information

A key NEA activity in the field of radioactive waste management is the organisation of independent, international peer reviews of national studies and projects.

At the request of the Belgian government, the NEA Secretariat established an international review team (IRT) to perform the peer review cited above. The IRT consisted of seven international specialists from the Czech Republic, France, Spain, Switzerland, the United Kingdom and the NEA Secretariat. The review team experts had no conflict of interest with ONDRAF/NIRAS and were chosen to bring complementary expertise to the review, in accordance with the Terms of Reference. The IRT was led by Maria Carmen Ruiz Lopez of the Spanish nuclear regulatory authority Consejo de Seguridad Nuclear. Further information on the review team members can be found in the report. During the review, the NEA Secretariat also served as the contact point between the IRT and the Belgian counterparts.

The experts reviewed the documentation provided to the review team and considered the additional information that ONDRAF/NIRAS supplied both in writing and as part of information exchanges during two working seminars, including a site visit in Belgium. In keeping with NEA procedures for independent reviews, neither the Belgian government nor ONDRAF/NIRAS have commented on this report, although ONDRAF/NIRAS had an opportunity to ensure the factual correctness of the review.

Related links

• International peer review: "The long-term radiological safety of a surface disposal facility for low-level waste in Belgium"
• NEA Radioactive Waste Management Committee
• ONDRAF/NIRAS

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