Carrières bij NRG.

For our business unit Consultancy & Services we are looking for an enthusiastic intern to assist us for a period of minimal 4 months. Are you interested in an internship at NRG, please apply for our following position:

Internship Reactor Core Design - location Arnhem


The core design of a nuclear reactor is a challenging task due to the theoretically infinite number of possible loading patterns. NRG's software ROSA (Reloading Optimization by Simulated Annealing) is successfully being used for in-core fuel management of more than twenty-five Pressurized Water Reactors (PWRs) across the world. ROSA combines a 3-D neutronics and thermal-hydraulic core simulator with a simulated-annealing optimization algorithm, which searches for an optimal loading pattern by means of a stochastic approach.

The code can evaluate up to billions of core design options in a day, based on any combination of more than sixty optimization parameters. These range from safety operational margins to energy production and fuel cost saving. Since a whole-core depletion calculation must be performed for each candidate loading pattern, computing speed is one of the essential requirements for ROSA. For this reason, its neutronics solver is based on the kernel method, a particularly fast type of nodal method in which assembly-size nodes are coupled via neutron interaction probabilities computed under a number of simplifying assumptions.


A version of ROSA is currently being developed for Boiling Water Reactor (BWR) core design. Compared to PWRs (for which the robustness of the kernel method has been extensively tested), this type of reactor has a significantly higher core heterogeneity, due to strong coolant density variations, heterogeneous fuel composition, and long-lasting insertion of control blades for power shaping. These features may invalidate or weaken some of the assumptions underpinning the kernel approach used in ROSA.
In the framework of the BWR development, the internship may focus on one of the following topics (depending on the interest of the applicant):

- An assessment of the impact of the approximations adopted in ROSA's neutronics solver on the solution of the optimization problem for BWR core design;
- The development of a method for control-blade pattern optimization;
- The extension of the code with new optimization parameters and additional functionality.


The internship will take place in the Fuel Management Services unit of the C&S (Consultancy and Services) department of NRG in Arnhem. The student will be working side by side with ROSA's developers. High flexibility is ensured for the time frame and duration of the internship.

Conditions of employment

The placement fee is ? 300 per month (for a fulltime internship). We also offer you a 3-day onboarding and a challenging working environment with a high level of knowledge.
Information & Application
To know more about this position or our company, please contact our corporate recruiter Nancy Roggeveen via 06-15590245 or mail to For more information about our company, check out our corporate business page

Safety investigations are part of the selection procedure.

terug naar de vacature lijst