GUINEVERE: a world premiere

The GUINEVERE Project is a nuclear system powered by a particle accelerator, called an Accelerator Driven System, or ADS. The accelerator has now been successfully connected to the VENUS-F reactor at SCK•CEN. Together with CNRS, CEA and other partners worldwide, SCK•CEN has designed for the first time a demonstration model of an ADS with a complete lead core driven by a particle accelerator. Professor Peter Baeten, Director of the Institute for Advanced Nuclear Systems at SCK•CEN, and Prof. Hamid Aït Abderrahim, Deputy Director General of SCK•CEN and director of the MYRRHA project, explain in the following interview the importance of this world premiere and look to the future.

Q: This coupling is a milestone in the history of nuclear science. What does it mean to researchers and engineers who looked forward to this moment for so many years?

A: Prof. Dr. Peter Baeten: As a researcher, I find it important to seek solutions to societal issues. The disposal and reduction of nuclear waste, which will also burdens future generations, is an issue that is very much alive in our society. The development of ADS technology enables the transmutation of long-lived nuclear waste. This means that we can reduce greatly the quantity and radio-toxicity of this waste. In this way we also decrease the time required for underground storage from several hundred thousand years to less than 1,000 years. The research that we perform today therefore provides a valuable contribution to a viable and sustainable future for ourselves and our children.

Q: In its 60-year history SCK•CEN has achieved several world firsts. How big was the challenge this time?

A: Prof. Dr. Peter Baeten: GUINEVERE is the result of excellent and efficient teamwork, both within SCK•CEN as well as with various international partners. By current standards within the nuclear sector, this project has been realized extremely quickly. The former VENUS facility was only shut down in April 2007 and less than three years later we inaugurated GUINEVERE. This is largely due to all the employees who have worked to optimize co-operation across different disciplines. Within SCK•CEN, the expert group "Nuclear Systems Exploitation" took the lead in the development of GUINEVERE. They were closely supported by their colleagues from "Nuclear Systems Physics" for neutron calculations and by the "Design and Engineering Office". In addition, we could rely on the "Central Technical Services" for the construction of the facility, on "Physical Control" for the safety studies and finally on the Purchasing Department. I would like to thank all these colleagues for their efforts in realizing GUINEVERE. I also want to acknowledge the company Vanhout nv of Geel, without whose efficient cooperation the facility could not have been built so quickly.

Q: Guinevere is a project with an international dimension. Which partners made a contribution alongside SCK•CEN?

A: Prof. Dr. Peter Baeten: The experiments are conducted within European Framework Programmes which focus on the transmutation of long-lived nuclear waste in an ADS. Ten research institutes from different countries are participating in GUINEVERE. One of our key partners is the Centre National de la Recherche Scientifique (CNRS). They developed and built the Genepi-3C accelerator on their site near Grenoble ​​ and prepared it for transportation to SCK•CEN in 2009. CNRS employees also helped with the installation of the accelerator in the VENUS installation. The Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA) in Cadarache helped us with the concept and infrastructure of the reactor and supplied the uranium fuel. Other partners include the German KIT and FZD, the Swedish KTH, the Italian ENEA and the Spanish CIEMAT. They conducted support studies in particular for the safety files. It was an international mix, but as I said, the cooperation with all parties on the site was very smooth because everyone was on the same wavelength.

Q: The GUINEVERE research facility was inaugurated on March 4, 2010, in the presence of the media and many VIPs. Why has it taken more than one year for the real coupling between the accelerator and the reactor?

A: Prof. Dr. Peter Baeten: At the beginning of 2010 SCK•CEN received the licence from the Federal Agency for Nuclear Control to build and test GUINEVERE. We took a whole year to test the non-nuclear parts of the reactor: the ventilation system, the monitoring system, the particle accelerator and so forth. We started the reactor in the critical mode in February 2011. After a series of detailed tests in this mode, we coupled the reactor to the accelerator and the system was switched to the sub-critical mode. This has never before been done with a fast lead core.

Q: How do you see the future for GUINEVERE?

A: Prof. Dr. Peter Baeten: We are now running an experimental program to validate the methods for determining the sub-criticality of the system in different operating conditions. Sub-criticality in an ADS is a very important safety parameter. Specific to an ADS is that a particle accelerator maintains the nuclear fission chain, as a neutron source outside the reaction. This offers great advantages in terms of safety: if we turn off the accelerator, it also stops the sub-critical nuclear reactor automatically. The condition of sub-criticality is essential for the safety of this type of reactor. We need to be able to make accurate measurements under these different operating conditions. The ultimate goal is to fine-tune the procedures for the operation and control of sub-critical reactors. The GUINEVERE project will thus contribute to the safety of future ADS's.

The second objective of GUINEVERE is the execution of experimental studies to characterize the MYRRHA core configurations. For this new research reactor, we have to study and validate different core configurations. Therefore, we converted the VENUS reactor into a quick zero power lead reactor (VENUS-F). With GUINEVERE we can validate experimentally the neutron codes calculated for MYRRHA, by characterizing the unique core, consisting of lead and uranium. These codes reflect the distribution of neutrons in the reactor which is important for control and safe operation. These experiments take place within the new European project FREYA which runs from 2011 to 2014. FREYA will contribute to the further development and refinement of accelerator driven systems.

Q: This successful coupling also brings MYRRHA one step closer?

A: Prof. Dr. Hamid Aït Abderrahim: The story of MYRRHA begins in 1997. After a feasibility study with a team of four people, we worked out the first draft. In 1999 we were involved with six people in a European Commission project to develop an experimental ADS, competing against two other industrial projects. We were very excited to develop MYRRHA and nothing could stop us. Yet we realized very clearly that we had started out on a long adventure, and that we would have many obstacles to overcome.

With GUINEVERE we crossed a major hurdle and we also proved at the European level what expertise we have in Belgium. We constructed a sub-critical reactor with a lead core and managed to couple it to a particle accelerator. Plus, our security authorities are qualified and sufficiently experienced to study such an innovative system, so that its safe operation is guaranteed. Therefore in 2006, when another crucial ADS demonstration project in the framework of EURO TRANS was stopped, I did not hesitate one minute to transfer this project over to SCK•CEN. We fought for six months to convince our European colleagues that the implementation of the experiment in our VENUS installation was a viable proposal.

I want to take this opportunity to thank the general management and the board of directors at SCK•CEN for the trust they have placed in the GUINEVERE project team. A motivated team that has made tremendous efforts for the development of the design, for the preparation of the safety studies, for the construction of the entire installation and for obtaining all necessary approvals. They deserve a great compliment. So for me, the most important result is that GUINEVERE showed that where there's a will, there's a way! I see GUINEVERE as a kind of training for the World Cup we will play with MYRRHA. GUINEVERE is actually a small scale model is with less power, hence my nickname "baby MYRRHA". To demonstrate the feasibility of the ADS concept is an important objective of the MYRRHA project, and GUINEVERE is the first step.

Q: Does GUINEVERE contribute in other ways to the development of MYRRHA?

A: Prof. Dr. Hamid Aït Abderrahim: With GUINEVERE we will perform experiments to characterize the MYRRHA core configurations. In this way we can validate the calculated neutron codes. The MYRRHA designers, who further optimize the design, will use these results to refine the previously defined safety margins. For the optimization of the MYRRHA design, this is a big step forward.

Abbreviations

• GUINEVERE: Generator of Uninterrupted Intense Neutron at the lead VENUS reactor

• VENUS: Vulcain Experimental Nuclear Study

• EUROTRANS: European Research Programme for the High Level Nuclear Waste transmutation or in an Accelerator Driven System

• FREYA: Fast Reactor Experiments for Hybrid Applications
  MYRRHA: Multi-purpose Hybrid Research Reactor for High-Tech Applications

Press releases

• GUINEVERE paves the way for MYRRHA – march 4  2010

• The Belgian Government gives its go ahead for the MYRRHA Project – march 4 2010

Websites

• www.sckcen.be
• freya.sckcen.be
• myrrha.sckcen.be