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Developing flexible matrices for transmutation targets

Apply now Before applying, please consult the guidelines for application for PhD

Transmutation of elements, or more strictly specific isotopes of an element, refers to the nuclear reactions which occurs under the effects of a neutron flux. Principally, it relates to nuclear fission and to neutron capture by the nucleus of the irradiated material. During irradiation of nuclear fuel a cascade of neutron capture reactions occurs, which eventually lead to a build-up of so-called major (Pu) and minor actinide elements (Np, Am, Cm). The accumulation of these transuranic elements is responsible for a significant fraction of the heat load in spent nuclear fuel, while also dominating the radiotoxicity over a timeframe of up to one million years after discharge from the reactor. Advanced technologies to process spent fuel are being developed, aimed to partition the actinide elements into separate fractions and re-manufacture them into so-called transmutation target materials. By irradiating these targets the long-lived, radiotoxic actinides can be transmuted into short-lived, light elements. An obstacle in the manufacturing of transmutation targets is the application of a suitable conversion process from the liquid state of the actinide feed (output by the spent fuel reprocessing step) and the solid state in which they are required as target material. At SCK CEN experience has been built up on the use of sol-gel chemistry to fabricate microspheres in which minor actinide elements may be incorporated. In particular, it was recognized that porous microspheres can act as receptacles for infiltration with aqueous solutions, which is advantageous when handling minor actinide elements where waste streams and dose rate accumulation need to be minimized. Depending on the application of the transmutation target, or constraints in the irradiation conditions, different types of host matrix materials need to be considered. The aim of the PhD project is to investigate conditions of sol-gel processes and subsequent fabrication steps to develop a portfolio of transmutation target manufacturing routes with different matrix types, specifically UO2, ZrO2 and ceramic composites with MgO. The intention is to build up capability and flexibility to select a host matrix and transmutation target shape/composition based on the specific application or constraints imposed by the irradiation facility.

The minimum diploma level of the candidate needs to be

  • Master of sciences
  • Master of sciences in engineering

The candidate needs to have a background in

  • Chemistry
  • Physics
  • Material science

Estimated duration

4 years

Expert group

Fuel Materials

SCK CEN Mentor

Leinders Gregory
gleinder [at] sckcen.be
+32 (0)14 33 31 63

SCK CEN Co-mentor

Acevedo Muñoz Beatriz
bacevedo [at] sckcen.be
+32 (0)14 33 32 61

Promotor

Vleugels Jozef
jozef.vleugels [at] kuleuven.be