Machine Protection studies for the ESS Proton Accelerator

The European Spallation Source (ESS)], which will be built in Lund, Sweden with commissioning planned for ca. 2020, is a spallation neutron source using a very high power 2 GeV proton beam as a driver. The beam current is 2.5 mA and the average beam power is 5 MW. One of the ESS' key tasks is to deliver neutron beams with a 95% overall reliability and to be operational at full power (average beam power of 5MW) for ~5000 h per year. In order to achieve these goals it is vital and highly important to perform a reliability, availability, maintainability as well as a risk analysis throughout the whole lifecycle of ESS. The University of Oslo has contributed to the ESS accelerator R&D in the fields of beam physics, machine protection and beam instrumentation. The performed ESS R&D has given the Oslo group competences in the design and operation of high-intensity proton drivers. This competence is also very valuable for the study of accelerator driven systems (ADS), including Thorium driven nuclear reactors. ESS has high ambitions for their machine protection system, due to the very high beam power. In this project new methods for machine protection for accelerators have been developed and presented at international accelerator conferences.

The primary objective of the PhD project as proposed here, is to contribute to research in the field of reliability analysis methods for MPS, with focus on applicability of these techniques during the ESS design, construction and operational phases. The scope of MPS is to protect the equipment of the accelerator, the target station, the neutron instruments and the conventional facilities from damage induced directly or indirectly by beam losses. The assigned design function of MPS is to switch off the p roton beam upon detection of critical or non-nominal conditions. The design function must be performed during beam operation periods. At the same time as MPS must assure protection of equipment it must avoid false beam stop triggers leading to unnecessary beam-unavailability or machine downtime. Conceptually, the role of MPS is to ensure maximum beam availability with high reliability. It is required to give special focus to the measures needed to achieve the ESS' mission goal with respect to the require d high beam availability and the related 95% reliability.