1. 1 BROOKHAVEN SCIENCE ASSOCIATES Presentation to ASAC R. Casey Radiation Shielding: Assumption and Design April 24, 2007

2. 2 BROOKHAVEN SCIENCE ASSOCIATES Preliminary Shielding Design Documents for NSLS II 1. Linac, NSLS II- TN 12 2. Booster & Storage Ring, NSLS II – TN 13 3. Storage Ring Supplemental Shielding – TN 21 4. Beamlines and Front Ends, NSLS II – TN 14 5. Ray Tracing Standards, NSLS II – TN 20 6. Activation Analysis, NSLS II – TN 15 & 16

3. 3 BROOKHAVEN SCIENCE ASSOCIATES Radiation Safety Workshop was Recently Conducted March 27 – 28, 2007 Membership S. Rokni (Chair) – SLAC R. Donahue – ALS P. Berkvens – ESRF D. Beavis – BNL C. Schaefer - BNL

4. 4 BROOKHAVEN SCIENCE ASSOCIATES Rad Safety Workshop Committee reviewed: Shielding methodology & assumptions Interlocks, Critical Devices, and Area Radiation Monitoring plans. Committee concluded: “ Given the status of the project, the design of the bulk shielding of the accelerator complex is well developed and is based on sound principles and reasonable assumptions. “

5. 5 BROOKHAVEN SCIENCE ASSOCIATES Desired Shielding Outcome Compliance with DOE Orders, Part 835, and BNL Administrative Controls < 25 mRem/year (.25 mSv) on-site to non-NSLS-II personnel; < 5 mrem/year (0.05 mSv) at site boundary Radiation exposure to users and staff ALARA – an administrative control level of 100 mRem/year (1 mSv) is desired We plan to achieve this through shielding and engineering controls; & supplemental administrative controls Based on current experience, we expect annual radiation exposures < < 100 mRem/year (1 mSv) to NSLS staff and users After verification, we expect short-term visitors will not be required to have dosimeters routinely

6. 6 BROOKHAVEN SCIENCE ASSOCIATES Shielding Policy Accelerator and beam line enclosures will be shielded to reduce exposure at the exterior surface of the shield during typical operation to 0.25 mRem/hr (2.5 uSv) in normally occupied areas to limit the maximum exposure to 500 mrem/year (5 mSv) (assuming 2000 hours occupancy). The storage ring outer wall will be shielded to 0.5 mRem/hr (5 uSv/hr) in direct contact with exterior; no full-time occupancy is expected or will be permitted within 1 meter of wall. This policy satisfies DOE Design Goals identified in 10 CFR 835.1002

7. 7 BROOKHAVEN SCIENCE ASSOCIATES Shielding Policy (cont.) Shielding calculations will use conservative source terms and attenuation factors Abnormal operating conditions, including Maximum Credible Incidents (MCI), will be evaluated Additional engineering or administrative controls will be specified based on severity of radiation levels under fault or non-typical conditions. Shielding and controls are considered adequate if MCI has low potential for exceeding 100 mRem (1 mSv) and can not exceed 2000 mRem (20 mSv)

8. 8 BROOKHAVEN SCIENCE ASSOCIATES Shielding Policy (cont.) Engineering control options include: Additional shielding (e.g. shadow shields, localized shields) Beam loss monitors with alarm in control room and (perhaps) interlock function Beam current monitors with alarm in control room and (perhaps) interlock function Area radiation monitors at the occupied areas with alarm locally and in control room and interlock function

9. 9 BROOKHAVEN SCIENCE ASSOCIATES Shielding Policy (cont.) Supplemental Administrative control options include: Operational procedures for operators and ESH staff during injection and routine operations Commissioning and shielding verification procedures Shielding configuration control Review of accelerator and beam design modifications Survey and posting procedures Passive area monitors

10. 10 BROOKHAVEN SCIENCE ASSOCIATES Bulk Shielding Calculation Methodology

11. 11 BROOKHAVEN SCIENCE ASSOCIATES Radiation Dose Equivalent Factors at 90 0 (comparison) Radiation Component Dose equivalent factors(mrem.m 2 /J) (Swanson) Dose equivalent factors(mrem.m 2 /J) (Sullivan) Dose equivalent factors(mrem.m 2 /J) (Shield 11) Bremsstrahlung2.801.391.12 Giant Resonance Neutrons 0.630.270.257 High Energy Neutrons 0.0750.0430.068

12. 12 BROOKHAVEN SCIENCE ASSOCIATES Radiation Attenuation Factors Used in Calculations

13. 13 BROOKHAVEN SCIENCE ASSOCIATES Accelerator Operating Conditions used in Calculations Linac 200 MeV 20 nC/pulse I hz operation Booster 3.6 GeV 15 nC per pulse 1 pulse / minute (typical operation) 1 hz operation for 500 hours per year considered Storage Ring 3.6 GeV 500 mA

14. 14 BROOKHAVEN SCIENCE ASSOCIATES Beam Loss Assumptions for Normal Operations Linac – 1% distributed loss at 200 MeV Linac to Booster injection efficiency – 50% Booster losses – 2% loss at any point at 3.6 GeV Booster to storage ring injection efficiency – 80% Non-injection region – 10% of stored beam losses at any point Stops in linac and booster designed for 100% loss at 1 hz

15. 15 BROOKHAVEN SCIENCE ASSOCIATES LINAC Bulk Shielding Estimates

16. 16 BROOKHAVEN SCIENCE ASSOCIATES Booster Bulk Shielding Estimates 1 Inboard wall (cm) Outboard wall (cm) Roof (cm) Booster Injection Region 2 108 98 Booster Non-injection Region 95 80 1 The Inboard and Outboard walls are at 1 m and the roof at 2 m from the beam 2 Supplemental lead shielding will be required around injection septum for 1 hz operation Booster shielding still in progress as adjacent occupancies are under discussion.

17. 17 BROOKHAVEN SCIENCE ASSOCIATES Storage Ring Bulk Shielding Estimates

18. 18 BROOKHAVEN SCIENCE ASSOCIATES LINAC - Credible Radiation Incidents 100 % of maximum accelerated beam is lost at some location in the linac enclosure, (20 nC/s is continuously lost) Dose Rate = 37.5 mRem/h (0.37 mSv/h) (at the exterior of shield on contact) 100 % injected beam to the booster is continuously lost at the linac-booster injection septum at 1 Hz. Dose Rate = 30 mRem/h (0.3 mSv/h) Mitigation/ control to prevent significant exposure Area Radiation Monitors with beam shut off capability Beam current monitors in the LINAC Additional supplementary shielding at the septum/stop (lead/poly) Operating procedures for operators during injection

19. 19 BROOKHAVEN SCIENCE ASSOCIATES Storage Ring (Credible Radiation Incidents) 100 % injected beam from the booster to storage ring is lost at any location in the storage ring (15 nC/s is continuously lost at some location other than injection region) Dose Rate = 300 mRem/h (3 mSv/h) (at the exterior of the experimental floor wall on contact) 100 % injected beam from the booster to storage ring is lost at any beamline front end due the shorting of a bending magnet (15 nC/s is continuously lost at a front end component) Dose Rate = ~ 500 mRem/h (5 mSv/h) (at the exterior of the ratchet wall ~ 0.5 m from the FE) (peak bremsstrahlung shielded with shadow shields) 100% of stored beam is lost at a point - ~ 8 mRem (0.08 mSv) Mitigation/controls to prevent significant exposure Area Radiation Monitors with beam shut off capability Beam loss monitors inside the Storage Ring Additional Supplementary Shielding (Shadow Shields) Operating procedures for operators defining actions during injection

20. 20 BROOKHAVEN SCIENCE ASSOCIATES Bulk Shielding Comparison