1. Radiological Aspects of ILC 2004. 12. 28. Hee-Seock Lee Pohang Accelerator Laboratory 2 nd Workshop of Korean ILC at PAL

2. High Power, High Energy Electron Accelerator, ILC  Underground Facility (Natural Shield : 20 m for TESLA, 30 m for ILS) (Natural Shield : 20 m for TESLA, 30 m for ILS)  Near Resident Area ( long facility ~ 30 km)  Limited No. of Access Point  Air Conditioning System with Long Path  Water & Cooling System  High Power Beam Dump (10 ~ 20 MW, e-beam dump, Bremsstrahlung photon dump) (10 ~ 20 MW, e-beam dump, Bremsstrahlung photon dump)  Huge IP (Interaction Point)

4. Radiological Impacts of ILC  EM Shower, Photonuclear, SR, Hadron  Primary Radiation  Secondary Radiation  Muon (L Soil = 400 m for 250 GeV )  Residual Activity  Environmental Problem  Beam Dump  Radiation Damage Shielding

5. Radiation for Radiation Worker  Tunnel Concrete Activation  Equipment Activation  Activated Air near Access Point(AP)  Activated Coolant in/out of Tunnel  Shielding at AP  One tunnel or Two tunnel (Access & Rescue) (Access & Rescue)

6. Radiation for Publics & Environments  Activated Air near Access Points  Soil Activation  Ground Water Activation  Tritium & Be-7 TESLA Shielding

7. Air & Coolant Activation  Air (near IP) Short Half-life Radioisotopes : C-14, N-13, O-15 Short Half-life Radioisotopes : C-14, N-13, O-15 Open Loop (long distance from release point) Open Loop (long distance from release point) Closed Loop (3 h cooling time after 1 month Op, 100 kW) Closed Loop (3 h cooling time after 1 month Op, 100 kW)  Water Coolant (Specially, Dump) Tritium, Be-7 : Control of NPP Level for 1 st coolant Tritium, Be-7 : Control of NPP Level for 1 st coolant  Helium Tritium : negligible for average loss of 0.1 W/m) Tritium : negligible for average loss of 0.1 W/m)

8. High Power Beam Dump  Mechanical Issues 10 ~ 20 MW, preventing leakage 10 ~ 20 MW, preventing leakage  Residual Activity around Beam Dump  Coolant Activation  Fail-safe  Interlock  Heavy Local Shield to reduce Env. Problems  Large Hall & Many Beam Dumps of ILC  Dump for Beam and Bremsstrhalung Photon

9.  Water Dump  In ILC, One dump for e- beam and bremsstrahlung photon  No Vacuum Trouble SLAC type Beam Dump for ILC Beam Dump for TESLA

10. Collimations and Damages  Multi-stage collimators and Magnetized Iron Spoilers  Life-times of Equipments and Detectors

11. Other Issues and Accidents  Radiation Monitoring System distributed along long facility : Budget & Operation  Publics always exist over the accelerator  Accidents Cooling Water Leakage Cooling Water Leakage Melting and Evaporation of Activated Materials Melting and Evaporation of Activated Materials Access Control Fail Access Control Fail

12. Recent Activities  KEK : Study on High Power Beam Dump  Fermi : Collimation and Background(BDIR)  TESLA : General Safety Analysis (Dump and problems near dump are not declared) (Dump and problems near dump are not declared)  KEK & PAL 2, 2.5 GeV Electron Beam 2, 2.5 GeV Electron Beam Photonuclear Reaction Study Photonuclear Reaction Study Activation Study of Low Activity Activation Study of Low Activity Concrete Concrete Activity around Water Dump Activity around Water Dump Since 2003(1998) Since 2003(1998)