Safety aspects electrical and gas safety Cs handling

Safety aspects: electrical and gas safety, Cs handling, radiation & fire protection Matthias Kronberger, Mats Wilhelmsson On Behalf of the Linac 4 ion source, EN/MEF and GS/ASE Teams Linac 4 ISWP review, 2011/06/07

Introduction For the Linac 4 IS and the IS / PG test stands at Bt. 357, a safety concept must be developed: electrical safety fire protection gas safety Cs handling radiation protection Aim: ü identification of possible hazardous risks ü define mitigation methods ü optimize personal safety and machine protection 2011/06/07 ISWP Review, CERN MK _ Safety Aspects 2

Introduction H 2 HV & RF equipment radiation fire Cesium potential hazards personnel gas accumulations in closed volumes x fire x x explosions x x electrocution x sparks x fire x release of radioactive material x internal & external exposure x activation of materials, contamination x destruction of equipment x x x intoxication, asphyxiation x fire, explosions x intoxication x corrosion chemical burns machine x x x . . . 2011/06/07 ISWP Review, CERN MK _ Safety Aspects 3

electrical safety: concept safety file ü HV equipment contained in a protected volume (HV protection cage) ü PLC-based safety interlock system for RF and HV ü safety file & procedures according to CERN safety regulations review ü training & information approval implementation commissioning Interlock system scheme Linac 4 3 Me. V test stand 2011/06/07 ISWP Review, CERN optimisation MK _ Safety Aspects 4

electrical safety: Linac 4 HV protection cage (proposed outline): size: ≈ 3× 3× 4 m 3 (7) contains: (1) (6) ü ion source ü HV racks (controls, power supplies) ü RF matching network ü H 2 bottle (location tbc) (1) (3) (2) (4) features: (5) (1) (2) (3) (4) H 2 bottles rack (grounded) HV racks 220 V iso transformer 2011/06/07 ISWP Review, CERN ü overhead crane for heavy equipment ü three access doors (5) pulsed HV iso transformer (6) ion source (7) LEBT MK _ Safety Aspects isolation transformer stored outside of cage to gain space 5

electrical safety: Linac 4 HV protection cage (proposed outline): general safety concept: ü no access to any HV equipment unless it is safe ü if access is forced HV and RF must be cut (7) (1) (6) (1) safety installations: (3) (2) ü warning signs ü door switches ü grounding rod ü local emergency stop ü safety gloves & hook (4) (5) machine protection: (1) (2) (3) (4) H 2 bottles rack (grounded) HV racks 220 V iso transformer 2011/06/07 ISWP Review, CERN (5) pulsed HV iso transformer (6) ion source (7) LEBT MK _ Safety Aspects ü prevent sparking between equipotential HV equipment during breakdowns calculate equivalent circuit 6

electrical safety: test stand IS & PG test stand HV protection cage (proposed outline): H 2 N 2 Ar differences to Linac 4: ü two separate test stands: ü ion source test stand (incl. beam extraction + LEBT) ü Plasma generator test stand (low-k. V extraction) ü H 2 bottle stored outside of building ü no crane 2011/06/07 ISWP Review, CERN requires upgrade of currently existing facility Integration study needed (evacuation paths!) MK _ Safety Aspects 7

Gas safety: concept minimize risk of H 2 release minimize risk of explosions 2011/06/07 ISWP Review, CERN ü use of appropriate hardware ü exhaust gas in vented areas ü use gas detectors coupled to an interlock system to detect accidentally released H 2 ü limit gas flow ü follow up gas consumption ü safety file ü procedures for installation, operation & maintenance of gas system ü training & information MK _ Safety Aspects 8

Gas safety: Linac 4 & Bt. 357 ü H 2 bottles stored in a safe location (Linac 4: fire cabinet; 357: outside of building) ü H 2 lines intercepted with redundant flow meters and electro valves to close gas line when sudden changes in gas flow are detected (leaks!) ü Flammable gas detectors at positions of potential gas release ü Acoustic & visual alarms 2011/06/07 ISWP Review, CERN MK _ Safety Aspects 9

Gas safety: interlock system Activated when gas detector measures an H 2 concentration ≥ 10% of the Lower Explosive Limit (LEL). (LELH 2 = 3. 6 vol. % H 2 in air) Example (Bt. 357): LEL = 10%: ü activate warning signs ü switch off gas supply ü inhibit RF pulse, gas injection & ignition ü Technical inspection 2011/06/07 ISWP Review, CERN LEL = 20%: ü call to fire brigade ü RF generator interlock ü Investigation by TI and fire brigade MK _ Safety Aspects 10

Cs handling Cesium: ü water reactive ü pyrophoric 2 Cs (s) + 2 H 2 O 2 Cs. OH (aq) + H 2 (g) Cs (s) + O 2 (g) Cs. O 2 (s) 2011/06/07 ISWP Review, CERN Cesium chromate: ü toxic (see also presentation of H. Pereira) MK _ Safety Aspects 11

Cs handling: risk mitigation storage: ü in accordance to CERN Safety Guideline C-1 -0 -1 ü elemental Cs: metal cabinet for water reactives ü Cs chromate: locked cupboard handling: ü only inside an inert gas-filled glove box (Ar or N 2) transportation: ü road: sealed transport container under inert atmosphere ü test stand: Ar bag detailed procedures for: ü Cs handling ü installation and removal of cesiated equipment ü cleaning & disposal Training & information 2011/06/07 ISWP Review, CERN MK _ Safety Aspects 12

Cs lab, disposal Lab safety: ü glove box + extracting hood ü storage cupboards ü fire extinguishers (class D) ü safety-eye wash fountain (EN 15154 -2) ü fire detectors ü floor drains covered with solid lid, NO water sprinklers Disposal: (based on ISIS concept) disposal path already identified 2011/06/07 ISWP Review, CERN MK _ Safety Aspects 13

radiation protection Sources of radiation: Bremsstrahlung Linac 4 LEBT radioactive sources 2011/06/07 ISWP Review, CERN Y-Sr ignition element MK _ Safety Aspects 14

radiation & fire protection radiation protection: ü Application of CERN rules for transportation, handling, and storage of radioactive components ü Procedures for operation & manipulation ü Adequate shielding (LEBT!) ü monitoring of personal and environmental dose 2011/06/07 ISWP Review, CERN fire protection: ü ü ü MK _ Safety Aspects smoke detectors Audible and visible fire alarms Fire protection equipment Manual firefighting means evacuation plan 15

Costs & manpower (Linac 4 tunnel + IS/PG test stand) costs (k. CHF) material costs + installation electrical safety HV protection cage Gas safety see presentation of D. Steyaert 30 0. 5 safety file, procedures 0. 2 calculation of HV protection cage equivalent circuit 0. 5 installation of gas systems 200 0. 4 safety equipment + installation 20 0. 1 safety file, procedures 0. 4 equipment Cs lab manpower (FTE) see presentation of H. Pereira installation safety file, procedures 0. 4 Radio protection equipment, installation, maintenance 15 0. 1 fire protection equipment 10 0. 1 Sum: 275 k. CHF, 2. 7 FTE 2011/06/07 ISWP Review, CERN MK _ Safety Aspects 16

Deliverables & Milestones (Linac 4 tunnel + IS/PG test stand) HV End 2011 Mid 2012 move PG test stand to final location HV protection cage Bt 357 electrical safety Bt 357 End 2012 Feb. 2013 HV protection cage Linac 4 electrical safety Linac 4 2011/06/07 ISWP Review, CERN gas Cs radiation fire modification of Bt 357 gas distribution Cs lab gas safety Bt 357 Cs oven test stand radiation protection Bt 357 fire protection Bt 357 connect l. S test stand + LEBT, functionality test gas distribution Linac 4 (H 2, N 2) gas safety Linac 4 fire protection Linac 4 Connect gas distribution in Linac 4 building MK _ Safety Aspects 17

Conclusions ü operation of Linac 4 and the IS/PG test stands require the development of a safety strategy according to CERN regulations: ü gas safety ü electrical safety ü radio & fire protection ü Cs handling ü estimated costs & manpower: 275 k CHF, 2. 7 FTE ü Deliverables: ü End 2011: Cs lab, Cs oven test stand ü Mid 2012: IS test stand Bt. 357 ü End 2012: Linac 4 HV protection cage & gas distribution ü Feb 2013: finish work at Linac 4 2011/06/07 ISWP Review, CERN MK _ Safety Aspects 18