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Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - MYRTE (MYRRHA Research and Transmutation Endeavour)

Teaser

Summary

MYRTE is carrying out research in order to demonstrate the feasibility of transmutation of highâ€level waste at industrial scale through the development of the MYRRHA (Multiâ€Purpose Hybrid Research Reactor for Highâ€Tech Applications) research facility. It is a firstâ€ofâ€aâ€kind, largeâ€scale nuclear research reactor that is designed to operate as an accelerator driven subâ€critical system and as a critical liquid metal cooled reactor.
The work programme is based on the current technological challenges of the MYRRHA project taking into account the current onâ€going R&D projects within SCKâ€¢CEN and the different European FPs and bilateral collaborations. MYRTE also makes use of the long standing European scientific communities in the different areas of expertise. MYRTE addresses key challenges in support of the MYRRHA design and preâ€licensing.

The main technological challenges for the development for MYRRHA are addressed based on the results of the previous design and R&D efforts.

Energy is one of the critical problems that society faces. The Strategic Energy Technology Plan, launched by the EC in 2007, focuses on the development of low-carbon energy technologies to the year 2050 and beyond. Nuclear energy was included in these technologies. For the further development of nuclear energy, the issue of high-level waste needs to be addressed. P&T offers an attractive solution for the minimization of this high-level waste. One of the major building blocks for the realization of P&T is the demonstration of a dedicated transmuter. MYRRHA responds to this challenge and MYRTE supports the development of MYRRHA.

Work performed

The objectives are subdivided along the axis of research:
ïƒ¼- Research, design and development of the MYRRHA accelerator
ïƒ¼- Thermal hydraulics
ïƒ¼- Chemistry of volatile radionuclides
ïƒ¼- Experiments in support of the MYRRHA design evolution
ïƒ¼- Actinide fuel
ïƒ¼- Dissemination & communication.

Accelerator R&D for ADS/MYRRHA: The MYRRHA Linac has to deliver a high power proton beam with very high reliability and with minimum beam losses. The emphasis within WP2 is on the injector which is considered to be the most critical part of the whole accelerator. The proton source and the low energy beam transport section have been put into operation successfully in combination with space charge experiments. The constructions of the first accelerating structure, the 4-Rod RFQ has started and is close to completion. To feed the RFQ a 160 kW cw RF amplifier is under development. The design has been optimized and construction will start beginning of 2017.
To control the RF phases and amplitudes of the injector cavities a Low Level RF (LLRF) control system is required. The design of the digital system is well progressed and prototype devices have been realized. The general control system has to be very reliable and as flexible as possible. As central Control System framework an EPICS system has been chosen. The MYRRHA Linac needs a powerful beam diagnostics system to monitor different beam parameters at different beam energies.
Beam simulation tools have been further optimized to perform updated end-to-end simulations and to implement a virtual accelerator tool. A reliability model of LINAC-4 (CERN) has been developed and will be validated with operation experience.
Prototypes of room temperature (CH) and superconducting (CH, Spoke) cavities have been performed successfully. As result all cavities exceeded the MYRRHA specifications.

Thermal hydraulics: here, experiments and simulations go hand in hand. The two large scale pool experiments experience some delays, but the impact in data delivery and therefore of the numerical part of the work is expected to be limited. The same is true for the dedicated heat transfer experiments and the flow induced vibration experiments. The fretting experiments are running according to schedule. The numerical work is on schedule and to a significant extent waiting for input from the experiments. Simulation models at CFD and system scale have been developed and are largely ready for application. The heat transfer model development is waiting for input from experiments and high fidelity numerical simulations. Two independent approaches implemented in different code platforms have been developed to simulate flow induced vibrations and have already been applied to determine preliminary modal characteristics of a MYRRHA rod bundle. A new numerical model has been tested for application to flow blockage formation simulations. A preliminary application has indicated that this new technique is promising but has also revealed some limitations, mainly due to high computational costs. Finally, a new coupled simulation tool coupling state-of-the-art sub-channel and neutronics codes is almost ready.

Chemistry of volatile radionuclides:
o Transpiration MS setup was developed and installed
o The system works. First transpiration MS measurements on mercury and tellurium were obtained. It was possible to quantify mercury evaporation in agreement with earlier investigations. Evaluation of tellurium evaporation results is ongoing
o A benchmark was developed for judging the reliability of the results for polonium containing molecules based on agreement between theory and experimental data on molecules containing poloniumâ€™s lighter homologues
o Preparation of LBE samples containing tracers for iodine and alkali metals were developed. These samples should be suitable for performing the envisioned evaporation and deposition studies
o Adsorption of Po on SS316L was studied for the 1st time
o Adsorption enthalpies

Final results

Through the technical progress as described above, the realization of MYRRHA comes closer and thus the perspective of realizing one of the major building blocks of P&T increases significantly.