FLUKA SPES Selective Production of Exotic Species Laboratori

FLUKA @ SPES (Selective Production of Exotic Species) Laboratori Nazionali di Legnaro LNL, Padova (IT) Istituto Nazionale di Fisica Nucleare (INFN) Mechanical design of the SPES production apparatus (Front-End) Ion e v cti IB) a (R dio Ra eam B 150 cm Prim (PPB ary Proto ) - 40 n Me. V Beam , 200 m. A B Target & Ion Source (TIS unit) PPB UCx target 1013 fission/s Antonietta Donzella, FLUKA Advanced Course and Workshop, November 2019 -Boulogne-Billancourt (Fr) RI

THE “CORE” OF THE SPES PROJECT: THE TARGET & ION SOURCE Isotope Separation On Line protons Fission fragments Ions Extraction Electrode Hot Transfer Line Ion Source (+40 k. V) 8 k. W proton beam UCx target discs 2000 C Intense neutron fields A. Monetti et al. , Eur. Phys. J. A. , 51 (2015) Limited TIS unit lifetime: one irradiation 30 day cycle of 15 days of PPB ON + 15 days of “cooling time"

THE SPES OPERATION MODE IM PR Y AR N TO O PR N LI E ON VE I T C N IOA ) LI RAD M (RIB BEA Horizontal Handling Machine (HHM) TIS unit Temporary Storage System (TSS) A. Andrighetto et al. , J. Phys. Conf. Ser. 966, 012028 (2018) Operation mode: 10 irradiation cycles of 30 days each per year

SPES RADIOLOGICAL PROTECTION ISSUES 1) Generation of radioactivity 2) Radiation exposure of workers and population 3) Storage of activated targets 4) Decommissioning and waste disposal Protect the individual in all planned exposure situations during operation, maintenance, decommissioning and rehabilitation J. Valentin, The 2007 Recommendations of the International Commission on Radiological Protection, ICRP Publication 103, Annals of ICRP, 37, No. 2/4 (2007).

FLUKA vs MCNPX CALCULATION OF THE RESIDUAL ACTIVATION OF THE SPES FRONT-END SYSTEM TOOLS: ü Two codes for Monte Carlo simulation: FLUKA and MCNPX+CINDER'90 ü Identical simulation models: geometry, materials, primary beam source ü Definition of geometry cells of interest ü Completely independent calculation methods RESULTS: ü Fission rate in the target ü Particle fluxes in the selected geometry cells ü Residual activities in the selected geometry cells at scored cooling times ü Radiological dose rate monitoring in the Front-End bunker ü Comparison between the two tools

MCNPX+CINDER’ 90 AND FLUKA: TWO DIFFERENT CALCULATION METHODS G. Battistoni et al. , Annals of Nuclear Energy 82, 10 (2015). FLUKA: activation study case ONE STEP CALCULATION • residual activation of the Front. End materials after the TIS unit removal • time evolution of the decay radiation in the Front-End production bunker FLUKA 2011. 2 x D. B. Pelowitz, MCNPX User's Manual, Version 2. 7. 0, LA-CP-11 -00438 (2011). W. B. Wilson, A Manual for CINDER'90, Version 07. 4 Codes and Data, LA-UR-07 -8412 (2008). Many samples, high computing time: Parallel running (Cloud Veneto) INFN and Padua University P. Andreetto et al. , EPJ Web of Conf. 214, 07010 (2019)

FLUKA-FLAIR INPUTS PHYSICS SETTING AND MODELS: PROTON SOURCE: RADIOACTIVE DECAY: IRRADIATION PROFILE: 15 d GEOMETRY… cooling times 200 m. A on target

THE SIMULATION MODEL OF THE SPES FRONT-END SYSTEM Mechanical Front-End design 3 D CAD-Creo Monte Carlo Front-End model MCNPX & FLUKA PRIM ARY Complex SPES Front-End geometry model PRO TON LIN E N IO E E N IV ) LI T C B OA (RI I D S RA AM BE

FISSION RATE IN THE TARGET FLUKA proton flux (cm-2 s-1) UCx target disks Primary Proton Beam 40 Me. V, 200 m. A Fission fragment yield in the target FLUKA: 0. 81 · 1013 s-1 A. Fasso et al. , FLUKA: a multi-particle transport code, CERN-2005 -10, INFN/TC 05/11, SLAC-R-733 (2005). MCNPX: 0. 79 · 1013 s-1 • • H. W. Bertini, Phys. Rev. 131, 1801 (1963). J. Barish et al. , HETFIS High-Energy Nucleon-Meson Transport Code with Fission, ORNL-TM-7882 (1981). Good total agreement but different shape in FLUKA and MCNPX Monte Carlo errors below 1%

THE REFERENCE GEOMETRY CELLS Monte Carlo Front-End model PRIM ARY PRO TON N IO E E N IV ) LI T C B OA (RI I D S RA AM BE LIN E 2 1 5 3 4 6 1. graphite collimator 2. SS 316 L element of gate valve 3. Ti-alloy proton bellow 4. Al-alloy structure on PPB line 5. Al-alloy structure on RIB line 6. SS 316 L piece of turbo-molecular pump

RESIDUAL ACTIVATION AT SCORING TIMES shutdown after 15 days of beam ON https: //tendl. web. psi. ch/tendl 2017. html. R= FLUKA / MCNPX 53 Cr(p, pp) 52 V 54 Cr(p, ppn) 52 V 15 day “cooling time” PPB B RI 2 Monte Carlo errors on the ratio R below 1% Bq = decays per unit time (s-1) SS 316 L (Fe 66%, Cr 17%, Ni 12%) geometry cell 2 PPB line 6 SS 316 L (Fe 66%, Cr 17%, Ni 12%) geometry cell 6 RIB line

RESIDUAL ACTIVATION AT SCORING TIMES https: //tendl. web. psi. ch/tendl 2017. html. shutdownafter 15 15 daysof ofbeam. ON ON R= FLUKA / MCNPX 27 Al(p, n) 27 Si 15 day time“ “cooling time” 15 day “cooling after 15 days beam ON B PPB 5 RI Monte Carlo errors on the ratio R below 1% Al-alloy (Al 97%) geometry cells 4 PPB line 4 Al-alloy (Al 97%) geometry cells 5 RIB line Good total agreement but incompatible results between FLUKA and MCNPX on the proton induced activation

AMBIENT RADIATION MONITORING IN THE BUNKER MCNPX Ambient dose equivalent rate d. H*(10)/dt (m. Sv/h) • • M. Pelliccioni, Radiat. Prot. Dosim. 88(4), 279 (2000). International Commission on Radiological Protection, Conversion Coefficients for use in Radiological Protection Against External Radiation, ICRP Publication 74, Annals of ICRP, 26, No. 3/4 (1996).

AMBIENT RADIATION MONITORING IN THE BUNKER Ambient dose equivalent rate d. H*(10)/dt (m. Sv/h) MCNPX Scoring time: t 10 15 day “cooling time“ after 10 complete cycles (one year) Agreement good enough to allow the use for the prediction of the radiological hazard Top view Italian legal dose levels for workers < 20 m. Sv per year

AMBIENT RADIATION EVOLUTION DURING THE FACILITY LIFE-TIME Ambient dose equivalent rate in a typical inspection position inside the Front-End bunker, versus the operation time PX Scoring time: t 10 1 st year 2 nd year 3 rd year 4 th year point 3 Ambient dose equivalent rate inside the Front-End bunker, calculated with MCNPX (long run time for FLUKA)

FLUKA CHALLENGES ü Modeling of the complex SPES Front-End geometry ü Shape of the 40 Me. V proton induced fission yield on 238 U target disks ü Mismatch with MCNPX on the proton induced activation ü Very demanding calculation time (parallel running)

BACKUP SLIDES

From: A. Monetti et al. , Eur. Phys. J. A. , 51 (2015) Fission fragment yield in the target FLUKA: 0. 81 · 1013 s-1 MCNPX: 0. 79 · 1013 s-1 Comparison of 238 U proton-induced fission yields between FLUKA simulations and experimental data of: V. A. Rubchenya et al. , Nucl. Instrum. Methods A 463, 653 (2001). FLUKA Monte Carlo errors are below 2% (except for the external points).