ProSafe-SLS offers ultimate reactor protection for the Reactor Institute Delft

A gem. That is how you can call the research reactor of the Reactor Institute Delft. The institute is a world leader in the development and production of instruments for research with neutrons and gamma radiation. To secure this gem for the future and to make it shine even more, the infrastructure around the reactor is being improved and expanded. In this way, a better response is being made to current and future educational, scientific, and social issues. As part of this, the decision logic of the reactor protection system has also been replaced. "For an environment like this, the rule is: Keep it safe and simple," says Niels van Wijk of TU Delft. "It is precisely by keeping it simple that such a unique environment can be made super-safe. That's why we chose Yokogawa's ProSafe-SLS system, which has been approved by the government for use in our nuclear environment."

In a regular nuclear power plant, heat is released during nuclear fission; this heat is used to generate steam and then to generate electricity. The Delft reactor, on the other hand, is a real research reactor. Of course, heat is also released here, but the focus is in the neutrons and gamma radiation that are generated and used to carry out scientific experiments. These experiments are of great importance to many companies in the food, microelectronics, steel, and plastics industries for the development of their products. The Reactor Institute Delft (RID) is also of great value to the healthcare sector. Together with academic hospitals, it is working on the development of diagnostic and treatment therapies to combat cancer, among other things. Finally, RID's neutron research is leading the energy sector to efficient and affordable electricity storage methods using hydrogen and batteries. This line of research is crucial for the energy transition and very interesting for the electric car industry, among others. The innovative facilities and instruments of the Reactor Institute Delft are available to researchers at Dutch universities and companies.

New level through upgrade and renewal

To make the research reactor of the Reactor Institute Delft more precise and widely applicable, the OYSTER project will upgrade and renew the reactor. In this project, the neutron source of the Delft reactor will be linked to a liquid-hydrogen cooling system. This will slow down the neutrons and make them 'controllable' in bundles.

A major benefit is the possibility to better manipulate the behaviour of neutrons, despite their physical elusiveness. New alternatives for measuring also emerge, so that it will even be possible to follow the production of materials and nutrients in real time. In addition, existing methods are improved by a factor of one hundred. The result? It is multifaceted: through innovation, RID retains its connection to the world's top international institutes. Scientific research at TU Delft and product development based on it in the Netherlands and beyond will also receive a significant boost. In addition, new treatment methods can be developed in healthcare and - last but not least - new possibilities arise in energy generation and storage. In a world that is dominated by energy transition, this rapidly attracts attention.

Renewal in the nuclear world

With the upgrade and renewal of the reactor, the reactor security system has also been replaced. Niels van Wijk: “This system is designed to activate systems that prevent safety limits from being exceeded, based on a large number of sensor data, including data from radiation monitors and pressure transmitters. In case of a risk, the decision logic of the safety system decides what measures are required." Until recently, existing relay-based logic was used for this purpose. Niels van Wijk continues: "Innovations in the nuclear world - especially when it comes to security systems - are not commonplace and require the involvement of the regulator Authority for Nuclear Safety and Radiation Protection (ANVS). It ensures that nuclear safety and radiation protection in the Netherlands meet the highest standards."

ProSafe-SLS: intrinsically safe and fully predictable

For the new reactor protection system, several systems were compared. "With PLC-based systems, checks are always needed to make sure they are still safe," says Niels van Wijk. "With ProSafe-SLS, however, Yokogawa offered an interesting alternative that is intrinsically safe. For us, it was a new technology that would be deployed on the highest security line. But the technology is 100 percent transparent and offers decision logic based on a magnetic core. Its operation is thus based on physical principles that are fully traceable and predictable. Furthermore, the operation of the ProSafe-SLS system is not based on software."

As a product, ProSafe-SLS is not certified for nuclear applications while the competing system was. Nevertheless, the composite system offered by Yokogawa has been approved by the regulator. Niels van Wijk: "Yokogawa's 'keep-it-safe-and-simple' solution proved to be the best, most reliable and safest approach. However, there was a requirement that the business processes that Yokogawa uses in building the system must also comply with nuclear standards. Yokogawa has had this certified by TÜV Rheinland in collaboration with RID. The final acceptance at Yokogawa also took place under supervision."

 

Government approval for nuclear application

Because the renewal of the safety system is a modification to the highest reactor safety class, the proposed choice also had to be submitted to the regulator. "After Yokogawa had shown what they could do and the solution was also certified by TÜV, there was completely open and transparent communication with the reactor institute and the regulator. Right from the start, Yokogawa let it be known that it would follow nuclear standards. That statement, in combination with the proposed approach, gave every confidence to award the contract to Yokogawa. It was also required that Yokogawa's business processes be certified by an independent party before the reactor was restarted. And the company has since completed this successfully. The chosen solution with ProSafe-SLS is seen as a good example of how commercially available equipment (COTS – commercial off-the-shelf) can be used in a nuclear application."

Following approval, the old system was removed wire by wire and ProSafe-SLS was installed. Initial commissioning was successful, and an extensive test protocol resulted in an equally successful Site Acceptance Test. All solenoids were also replaced by a more reliable type and configuration. This is a good step towards the long-term and safe operation of this leading research facility. Claudy de Groote of Yokogawa: "The successful execution of this project underlines our close involvement in the Dutch and international nuclear market and its requirements. With unique technology, open and transparent communication and an excellent knowledge of safety, this cooperation with RID is a fine example that shows the added value of Yokogawa for nuclear projects."

More information

Would you like more information about this case or ProSafe-SLS? Please ask your local contact person of Yokogawa or contact the marketing department in the Netherlands via marketing.nl@yokogawa.com.