Availability modeling approach for future circular colliders based on the LHC operation experience

Abstract

Reaching the challenging integrated luminosity production goals of a future circular hadron collider (FCC-hh) and high luminosity LHC (HL-LHC) requires a thorough understanding of today's most powerful high energy physics research infrastructure, the LHC accelerator complex at CERN. FCC-hh, a 4 times larger collider ring aims at delivering 10-20 ab −1 of integrated luminosity at 7 times higher collision energy. Since the identification of the key factors that impact availability and cost is far from obvious, a dedicated activity has been launched in the frame of the future circular collider study to develop models to study possible ways to optimize accelerator availability. This paper introduces the FCC reliability and availability study, which takes a fresh new look at assessing and modeling reliability and availability of particle accelerator infrastructures. The paper presents a probabilistic approach for Monte Carlo simulation of the machine operational cycle, schedule and availability for physics. The approach is based on bestpractice, industrially applied reliability analysis methods. It relies on failure rate and repair time distributions to calculate impacts on availability. The main source of information for the study is coming from CERN accelerator operation and maintenance data. Recent improvements in LHC failure tracking help improving the accuracy of modeling of LHC performance. The model accuracy and prediction capabilities are discussed by comparing obtained results with past LHC operational data.

An open modelling approach for availability and reliability of systems

“…For example, in cases from the metal industry, robotics, and nuclear industry, we have required advanced features for (i) combination of FTA and FMEA analysis [8], (ii) multi-state modelling of partial process flows, (iii) dynamic rules for backup power supply use [9], and (iv) definition of exclusive stochastic consequences [10]. The extensive use of the advanced features was required in our particle collider availability model [11], which prompted us to develop OpenMARS. Like in the presented example, the model combines a fault tree model of failure logic, Markov models of operational cycles, and a function model for production calculation.…”

“…In an actual case the model could be more complex but, in our opinion, this simple case captures the core concepts of production process modelling and makes explaining them easier. For example, our availability model for a particle collider uses a similar modelling approach [11]. The example shows the basic use of the fault tree, Markov, and function models.…”

“…Various demanding use cases prompted us to add new advanced features for the modelling of complex relationships and dynamic operation changes [6,7,8,9,10]. The use of ELMAS for availability modelling of future circular colliders [11] in the European Organization for Nuclear Research (CERN) highlighted the challenge that the addition of customized domain-specific features required programming skills from the modeller. This motivated CERN to launch a research and development (R&D) project in collaboration with Tampere University of Technology and Ramentor.…”

“…The example uses a fault tree model for system failures, a Markov model for processing phase changes, and a function model for production calculation. This type of model is one of the key elements in our particle collider availability study [11].…”