BNL S-Band Electron LINAC’s

1. 2009 DOE Accelerator Safety Workshop BNL S-band LINAC Fire Safety ConcernsAugust 19, 2009A. Ackerman

2. BNL S-Band Electron LINAC’s • ‘S-Band’ Electron LINAC’s • 2 – 4 GHz range Klystron • Modulators contain a Pulsed Forming Network – supply high voltage & current pulse to klystron • Capacitors (store energy) • Inductors (shape the pulse; filters) • Thyratron (switch) • ~150 lbs of plastic, oil, plastic insulated wire • Four S-Band LINAC’s on site • National Synchrotron Light Source (NSLS) • Source Development Laboratory (SDL) • Accelerator Test Facility (ATF) • Laser Electron Accelerator Facility (LEAF) SLAC Design

3. BNL S-Band LINAC’sFire History • Three significant capacitor fires • NSLS: 1999; ~$95k loss • SDL: 2003; ~$10k loss • ATF: 2009; ~$100k loss • Lessons from 1999 • Too much combustible material • Capacitors not well suited to application • Air bubbles develop; Dielectric fluid not well distributed; Arcing results in fire • Difference between operation and arcing is subtle • Cannot prevent first arc, can discontinue power after the first event • Capacitors do not need forced air cooling • Need positive mechanism for power disruption (emergency stops)

4. BNL S-Band LINAC’sFire History • Corrective actions from 1999 • Use Glastic • Maintenance program for capacitor; different model • Arc detection • Smoke detection • Audio monitoring • Emergency power shut off switches • Response procedures • No fire suppression • Minimize fire damage • Keep adequate replacement parts

5. Accelerator Test Facility (ATF; Bldg 820) Overview • Accelerator Test Facility • 70 MeV electron Linear Accelerator (LINAC) • Four beam lines • Electron / Laser interaction research / testing • S-Band LINAC • 2 Klystrons

6. ATF; The Fire

7. Accelerator Test Facility (ATF; Bldg 820) Fire Investigation • Investigation team; 8 members; BNL • Incident description • Causal analysis • 7 causal factors; • Root, Direct, 5 contributing • Judgments of need; 5 statements • ATF design review for restart • Site wide corrective action closure • Facility transfer • Design & maintenance stds; (HV) • ATF operator qualification • Final Report; dated April 9, 2009 • Comprehensive, well organized, concise • Good basis for Corrective Action Planning

8. ATF Fire Corrective Action Planning CommitteeProgress Corrective Action Planning Committee formed • Scope • Review investigation report; focus on causal analysis • Develop corrective action plan to address judgments of need • 9 members; BNL • Corrective action plan ‘strategy’ determined • High voltage (HV) pulsed power focus • Institutional issues focus • Initial report complete; includes HV Pulsed Power Corrective Action Plan • DOE Lessons Learned document completed; distributed soon

9. ATF Fire Corrective Action PlanningHV Pulsed Power • Working Group formed • 8 members; 7 BNL; 1 ORNL • Charge: 3 ‘phases’ • Return ATF to safe operation; design review; 08/31/2009 • Fire safety design review; 4 S-Band LINACS • Establish review, design, control, & maintenance requirements for HV pulsed power on site.

10. ATF Fire Corrective Action PlanningATF Conduct of Operations Review • Working Group formed • 3 members; BNL • 2 meetings completed; third scheduled • Charge: • Review ATF Conduct of Operations program for effectiveness and compliance with DOE Order 5480.19 Change 2

11. ATF Fire Corrective Action PlanningMore to come • ‘Immediate’ need focused on BNL HV Pulsed Power • Understand the systems in place and the risks they present • Apply consistent controls (fire or arc detection, procedures, disconnects …) • Establish maintenance criteria • Assure adequate rigor in ‘Conduct of Operations’ • Institutional need focused on management systems, policy, … • sharing information and resources • organizing management changes • defining and meeting the resource needs for accelerator (or other facility level equipment) maintenance and operation • implementing complete and consistent corrective actions • establishing standards for equipment design and maintenance

12. End