Marcus M. Morgenstern DGS-RP-AS LIU-PSB meeting - June 18 th , 2015 -
Introduction Updated study previously performed by J. Blaha • (2013) Updates include: • Dump geometry • Shielding geometry • Aim: • Study radiological assessment for HSTS to fulfil safety • requirements Preliminary prompt and residual dose rate maps for updated • shielding – done 2 Radiological study for HSTS @ L4 – M. M. Morgenstern DGS-RP - 2015-06-18
Schedule of L4 commissioning 3 Radiological study for HSTS @ L4 – M. M. Morgenstern DGS-RP - 2015-06-18
Linac4 accelerator – commissioning phase Installation of HSTS 4 Radiological study for HSTS @ L4 – M. M. Morgenstern DGS-RP - 2015-06-18
Outline of HSTS Linac2 5 Radiological study for HSTS @ L4 – M. M. Morgenstern DGS-RP - 2015-06-18
The Linac2 / Linac4 interface • Linac2 Classification: • interlocked primary beam area (no access during operation) • Limited Stay Area due to residual dose rate levels (access during TS, YETS … .) • Building 363 (Linac2 racks, amplifiers, Linac2 control room … .) is classified as a Simple Controlled Radiation Area 363 6 Radiological study for HSTS @ L4 – M. M. Morgenstern DGS-RP - 2015-06-18
Prompt dose rate from Linac4 operation (Previous study) Exclusion area 7 Radiological study for HSTS @ L4 – M. M. Morgenstern DGS-RP - 2015-06-18
Exclusion area … .. Fences have been installed 8 Radiological study for HSTS @ L4 – M. M. Morgenstern DGS-RP - 2015-06-18
Radiation monitoring • RAMSES monitor + ARCON monitor available • Radiation alarm level (10 / 20 µ Sv/h low/ high) on RAMSES • Typical dose rates during Linac2 operation 5 – 10 µ Sv (PAXLN202) • Idea: move one of the monitors to L4 tunnel Linac 2 9 Radiological study for HSTS @ L4 – M. M. Morgenstern DGS-RP - 2015-06-18
Transition Linac4 -100 MeV to 160 MeV + HST Beam dump setup used for 100 MeV • commissioning partially (shielding) re-used for the HST in the transfer line Core has to be replaced as the core used at • 100 MeV cannot sustain the 160 MeV (operation done in 867) Work and Dose planning to be done … • 10 Radiological study for HSTS @ L4 – M. M. Morgenstern DGS-RP - 2015-06-18
Geometry updates I - shielding Downstream concrete • shielding extended from 80 cm to 1.2 m in thickness Lateral iron shielding doubled • in thickness, i.e. 40 cm compared to 20 cm before 11 Radiological study for HSTS @ L4 – M. M. Morgenstern DGS-RP - 2015-06-18
Geometry updates II - dump SSS shielding Downstream Thanks to Filippo Stefanini Concrete shielding Dimensions taken from 2D shielding • drawings and 3D Inspector model Material composition still to be • confirmed Trolley Core/Jacket/Cooling FLUKA model 12 Radiological study for HSTS @ L4 – M. M. Morgenstern DGS-RP - 2015-06-18
FLUKA Simulation setup Split beam according to 5% on internal • dump; 95% (= stripping foil efficiency) on main dump Simulation results are merged • Used for prompt Maximum dose rate dose rate calculation during day time 13 Radiological study for HSTS @ L4 – M. M. Morgenstern DGS-RP - 2015-06-18
Prompt dose rate Linac4/Linac2 junction Linac2 tunnel • accessible during 8 8 6500 10 6500 10 Y [cm] Sv/h] Y [cm] Sv/h] 7 7 10 10 µ µ Linac4 operation Prompt dose rate [ Prompt dose rate [ 6 6 10 10 6000 6000 5 5 10 10 Downstream 4 4 5500 10 5500 10 • 3 3 10 10 shielding sufficiently 5000 2 5000 2 10 10 10 10 reduces dose from 4500 4500 1 1 1 1 10 − 10 − main dump, but 4000 − 2 4000 − 2 10 10 − 10500 − 10000 − 9500 − 9000 − 8500 − 10500 − 10000 − 9500 − 9000 − 8500 Z [cm] Z [cm] doesn’t cover @Linac2 level @Linac2 amplifier gallery internal dump Prompt dose rate 5000 8 10 Y [cm] Sv/h] • 7 10 µ seems similar to Prompt dose rate [ 6 4500 10 5 10 previous study, 4000 4 10 3 10 though detailed 3500 2 10 10 evaluation of profiles 3000 1 necessary to provide 1 10 − 2500 − 2 10 − 10400 − 10200 − 10000 − 9800 − 9600 − 9400 − 9200 − 9000 final answer of Z [cm] Linac4 tunnel classification 14 Radiological study for HSTS @ L4 – M. M. Morgenstern DGS-RP - 2015-06-18
Residual dose rate map 4 4 10 10 Y [cm] Sv/h] Y [cm] Sv/h] 4000 4000 Apparently, the 3 3 10 10 • µ µ Residual dose rate [ Residual dose rate [ 3800 3800 2 2 10 10 3600 3600 10 10 most activated 3400 3400 1 1 − 1 − 1 3200 10 3200 10 − 2 − 2 10 10 3000 3000 components are the − 3 − 3 10 10 2800 2800 − 4 − 4 10 10 2600 2600 − 5 − 5 10 10 beam dumps − 10400 − 10200 − 10000 − 9800 − 9600 − 9400 − 9200 − 10400 − 10200 − 10000 − 9800 − 9600 − 9400 − 9200 Z [cm] Z [cm] 1h cooling time 8h cooling time 4 4 10 10 Y [cm] Sv/h] Y [cm] Sv/h] 4000 4000 After ~1 week of 3 3 10 10 • µ µ Residual dose rate [ Residual dose rate [ 3800 3800 2 2 10 10 3600 3600 10 10 cooling time the 3400 3400 1 1 − 1 − 1 3200 10 3200 10 − 2 − 2 10 10 3000 3000 residual dose drops − 3 − 3 10 10 2800 2800 − 4 − 4 10 10 2600 2600 − 5 − 5 10 10 10400 10200 10000 9800 9600 9400 9200 10400 10200 10000 9800 9600 9400 9200 − − − − − − − − − − − − − − below 1 µ Sv/h Z [cm] Z [cm] 1d cooling time 1w cooling time Though profiles • 10 4 10 4 Y [cm] Sv/h] Y [cm] Sv/h] 4000 4000 3 3 10 10 µ µ Residual dose rate [ Residual dose rate [ 3800 3800 needed for exact 10 2 10 2 3600 3600 10 10 3400 3400 1 1 numbers − 1 − 1 3200 10 3200 10 − 2 − 2 10 10 3000 3000 − 3 − 3 10 10 2800 2800 − 4 − 4 10 10 2600 2600 − 5 − 5 10 10 10400 10200 10000 9800 9600 9400 9200 10400 10200 10000 9800 9600 9400 9200 − − − − − − − − − − − − − − Z [cm] Z [cm] 1m cooling time 6m cooling time 15 Radiological study for HSTS @ L4 – M. M. Morgenstern DGS-RP - 2015-06-18
Conclusion/Outlook Dose rates similar to previous study, though further investigation (e.g. • profiles) are required to get final conclusion on impact of updated shielding Update/cross check activation of components • Check necessity for material updates in geometry (~1-2 weeks) • Steel components (SSS vs. SS316LN … ) • Iron shielding (“normal” iron vs. cast iron) • Decommissioning studies ongoing (~1 week) • Simulation already done, though lacking analysis of results • Perform calculation whether beam power can be increased for • updated shielding (~1-2 weeks) Study runs in parallel to 160 MeV commissioning run study for main • beam dump Documentation in progress • Assuming missing information can be gathered soon and everything • runs smoothly, final results are expected in a few weeks time scale 16 Radiological study for HSTS @ L4 – M. M. Morgenstern DGS-RP - 2015-06-18
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