Abstract. The European Spallation Source (ESS) is currently in the construction phase and should have first beam on Target in 2019. ESS, located in Sweden, will be the most powerful spallation neutron source worldwide, with the goal to produce neutrons for research. As an inkind partner the Forschungszentrum Juelich will among others, design and manufacture the four liquid hydrogen Moderators, which are located above and below the Target. Those vessels are confining the cold hydrogen used to reduce the energy level of the fast neutrons, produced by spallation in the Target, in order to make the neutrons usable for neutron scattering instruments. Due to the requirements [1], a fluid dynamic analysis with pressure and temperature depended hydrogen data, taking into account the pseudo critical phenomena and the pulsed neutronic heating (pressure waves) is necessary. With the fluid dynamic results, a structure mechanical analysis including radiation damage investigation (RCC-MRx code [5]), low temperature properties as well as strength reduction by welding can be realized. Finally, the manufacturing and welding completes the design process.

Catalyst could significantly improve thermal decomposition performance of energetic materials. However, different approaches for dispersing catalyst into energetic materials lead to quite different results. Generally, improved homogeneity of the mixture always results in better performance. In this paper, a novel method was applied on synthesizing nanoceria; at the same time, electrospray method was introduced to produce homogenous RDX/ceria micropowder. The mixture was characterized and tested by scanning electron microscope-energy-dispersive spectroscopy and differential scanning calorimetry-thermogravimetry. Kissinger method was employed to calculate activation energy of different specimens according to DSC data. Results indicated that with electrospray formation, catalyst (nanoceria) could be evenly dispersed into RDX. In contrast to pure RDX, RDX/ceria mixture could decompose at a lower temperature and has lower activation energy. The calculation results of critical explosion temperature indicated that the mixture is safe for storage and process operation. This study points out a potential way to develop new method to make energetic/catalyst mixture.

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