ISIS SYNCHROTRON VACUUM SYSTEM REPLACEMENT OF HIGHLY RADIOACTIVE

ISIS SYNCHROTRON VACUUM SYSTEM & REPLACEMENT OF HIGHLY RADIOACTIVE COMPONENTS IN STRAIGHT 1 By Shaun Hughes

Outline • • Description of vacuum system. Controlled dose limits. Radiation safety protocol. Radiation shielding for straight 1 replacement. Straight 1 before replacement. Dose rate levels from straight 1. Benefits of replacement.

Synchrotron & EPB • • High vacuum system built to UHV standards. Built to be highly reliable, robust and be able to withstand high levels of radiation. Large tapered flanges, clamps and seals. Operating pressure. Volume. Pumps. Valves. RGA.

Ring Vacuum Ion Pumps

Target Containment Vessel volume 30, 000 ltrs

Why Ion Pumps? Pump Comparison Pump Type Standard Turbo Maglev Turbo Cryo Diffusion Ion Radiation Resistant Maintenance Free

Removal of a Main Dipole Magnet

Dose Limits For Controlled Areas At ISIS Designation Legal whole body limit Operational limit to keep doses ALARP Comment Classified RAL Employee 20 m. Sv per year 1 m. Sv per main task 3 m. Sv per year 6 m. Sv RAL formal investigation Main tasks limited to 200 m. Sv per day Classified RAL trainee or apprentice 6 m. Sv per year 16 to 18 yrs of age and supervised by classified person Non-classified Contractor 1 m. Sv per year 50 m. Sv per day Maximum 500 m. Sv per year Visitors 1 m. Sv per year 10 m. Sv per visit 8 hr limit per visit Must be accompanied by an experienced RAL person

Working In The Synchrotron Area • Risk assessment and radiation safety protocol is required. • Detailed description of work and protection method. • Justification for carrying out this work. • Area and location of work. • Duration, commencement and completion dates. • Acceptance criteria and limiting conditions. • Duties, resources, responsibilities and preparation work are defined. • Lifting equipment, shielding, ventilation extract, personal protective equipment etc, required for the job.

Straight 1 Radiation Protocol Serial Action Whom Initials Time Min Dose Rate m. Sv/hr Dose m. Sv Protection Method 1 . Move 2 flasks, HP jib crane, body shield with glass window and flexi lead shielding into controlled area. IS, BB, KW, JA 30 20 10 Distance 5 m and shielding 2 Remove HEP rig, crop and place in containment flask. MK, JL, AH, DB, KW, JA 10 1500 250 Suspended shielding, distance 2 m 3 Remove DALEKS, crop rods and place rods in a containment flask. MK, JL, AH, DB, KW, JA 10 200 3 Distance 5 m and shielding 4 Disconnect cables from module 24 DW, DA, SP, NL 3 2500 125 Time distance and shielding 5 Undo bellows connections for module 24, remove bellows and place bellows and seals into a flask. SH, GM, JA 3 2500 125 Shield, distance 0. 5 m

Radiation Shielding For Straight 1 Upgrade Movable concrete shielding with remote TV cameras Movable body shielding with lead glass window Low radiation area compound with camera controls & monitor screens Controlled access points

Straight 1 Before Replacement Why Replace Straight 1 • Septum magnet aperture • Water flow • Faulty ion pumps • Shielding • Protect against physical damage

Dose Rate Levels From Straight 1 Active Components Item Close up Beta / Gamma dose Rate m. Sv/hr Comment Module 24 15000 Stored in R 40 Active Compound Module 23 22000 Stored in R 40 Active Compound Extract Septum Magnet 50000 Stored in R 40 Active Compound Singlet Magnet 12000 Stored in R 6 Active Compound Doublet Magnet 21000 Stored in R 6 Active Compound Trench Concrete 50 Left in Straight 1 Trench Metal plates 150 Left in Straight 1 Cropped components in 40 gallon storage drums 100 to 500 Stored in R 40 Active compound

Straight 1 Prebuild & Test • Individual items vacuum tested before assembly • Built into modules and vacuum tested • Full assembly and vacuum test of complete straight • Timed trial runs on removal and installation of components • Use concrete and lead shielding during these trials

Straight 1 After Replacement Benefits of Refurbishment • Ion pumps shielded • Remote clamps • Modules quick & easy to replace • Larger upgraded collector system • Better management of beam trapping losses • Larger aperture through septum magnet for increased beam current

Acknowledgements ISIS Vacuum Team – S Hughes – G Matthews – D Stringer – R Symes