ISOLDE Front-End design review – Details of previous faults AP.Bernardes on behalf of EN-STI-RBS team Acknowledgements: B.Conde Fernandez, K.Kershaw, S.Marzari, M.Delonca
Design Review Frontends Isolde Outline Failures Target valves and FE shutters Extraction electrodes Coupling table Cables Others Summary Conclusion 15 June 2016 Design Review Frontends Isolde
Design Review Frontends Isolde Target valve failures Indicators Estimation Frequency >1 per year Collective dose impact 2015: 1.4mSv 2014: none … Physics impact Low Every year several targets are found not fully closed (identified before target transfer to ISR) Not possible to identify the position with precision (no sensor no switch) Most of the times, target can be removed without problem by the robot 15 June 2016 Design Review Frontends Isolde
Design Review Frontends Isolde FE shutter failures Indicators Estimation Frequency ≈ 1 every year Collective dose impact 2015: 1.4mSv Low Physics impact Failure may be due to previous target shutter failures? (target O-Rings out of position) Not possible to identify the position with precision (no sensor no switch) 15 June 2016 Design Review Frontends Isolde
Target and FE shutters failures Failures origin Compressed air (pollution, insufficient pressure, etc.) Lack of valves lubricant Target O-Rings out of position Air leak on FE shutter piston (reduce strength) Wrong calibration of FE shutter piston No precise indicator for these failures 15 June 2016 Design Review Frontends Isolde
Extraction electrodes failures Indicators Estimation Frequency ≈ 1 every 3 years Collective dose impact Medium Physics impact Position identified Mechanical system not fully accessible (only first part) 15 June 2016 Design Review Frontends Isolde
Extraction electrodes failures Failures origin Loosened screws Default on gears Wrong calibration of extraction electrode Extraction electrode felt from support (No end-stop) FE shutter closed on extraction electrode (No interlock) Extraction electrode position identified but not precise enough some time to understand the failures 15 June 2016 Design Review Frontends Isolde
Coupling tables failures Indicators Estimation Frequency >1 per year Collective dose impact Medium Physics impact New design in 2014, optimized in 2016 Position identified with switch and potentiometers since 2016 (do not allow to know if the target is ”vacuum" clamped Reduce gas storage capacity ) Piston fully accessible and fast to repair design 15 June 2016 Design Review Frontends Isolde
Coupling tables failures Failures origin Air leak on coupling table piston (reduce strength) Lack of clearance on coupling table movement Lack of clearance on potentiometer axis Misalignment of coupling table Wrong calibration of coupling table Coupling table position identified but but not precise enough some time to understand the failures 15 June 2016 Design Review Frontends Isolde
Design Review Frontends Isolde Cable damages Cable damages due to irradiation and some mechanical constraints: Cables not easy to change if needed, no fast repair design 15 June 2016 Design Review Frontends Isolde
Design Review Frontends Isolde Others Radiation damage to material Corrosion 15 June 2016 Design Review Frontends Isolde
Summary Failure Frequency Collective dose impact Physics impact Target valves >1 per year 2015: 1.4mSv 2014: none … Low FE shutters ≈ 1 per year Extraction electrodes ≈ 1 every 3 years Medium Coupling table Cables Standard hazards on target area (preventive maintenance) Others 15 June 2016 Design Review Frontends Isolde
Design Review Frontends Isolde Conclusion Most of FE failures come from mechanical movement Mechanical movement should be suppressed or reduced as much as possible If not possible mechanical movement should be as simple as possible Moveable parts should be placed outside in order to be accessible for visualization or repair and fast intervention When possible moveable parts should be designed to be repaired with Telemax When possible back-up solution should be envisaged 15 June 2016 Design Review Frontends Isolde