Super Beam Simulation: radiation/activity, dose rates issues towards costing

WP2 - layout shielding towards costing 1

Super Beam Simulation: radiation/activity, dose rates issues towards costing

Talk’s Layout:

Material quantities for the SuperBeam Layout

Activities for target and Dose rates for a single target/horn for different cooling times at storage area

4horn layout: dose rates in target/horn station and preliminary activity study in the rock (molasse) surround it

Conclusions/Future


Material for SuperBeam

1st order SuperBeam layout beam (based on T2K design) : no service/power supply galleries and collimators, no proton beam tunnel.

Requirements: concrete to confine all/most of the energy deposited by secondary particles

• minimize the activation in the rock (molasse) and the dose rotes of other galleries • minimum activation at the edge of the concrete

concrete

Fe for shields, vessels and DT graphite for

beam dump

rock: molasse@CERN


Tables for different Material

concrete shields Fe: vessels, shields graphiteDownstream 1.95target/horn gallery 3.4 0.2Decay Tunnel 11 0.04Beam Dump 5 .8 3Total in kt 21.35 1.04 3


Super Beam layout

Design includes: Proton Driver line Experimental Hall

MW Target Station Decay Tunnel Beam Dump

Maintenance Room Service Gallery

Power supply Cooling system Air-Ventilation system

Waste Area

deca

y tu

nnel

(25

m)

spare area

beam

target/horn station

shielding

beam dump

horn power supply and electronics

gallery

hot cell


Target Activity at Storage Area study set up: packed Ti target, 66%dTi

1.3MW beam, 200days of irradiation no other activation at storage area


radiation limits as in CNGS notes:

rates (e.g.):at 60cm distance from the outer conductor (calculation of the rates using 20cmx20cmx20cm grid binning through out the layout -> choose a slice of x-axis with 20cm thickness and 60cm away )

Dose Rates for target/horn at Storage Area, I

Limits per 12-months period (mSv)Public Workers

France < 1 < 20Switzerland < 1 < 20CERN < 0.3 < 20, if .gt. 2mSv/month

report to Swiss authorities

plotsz

x


Dose Rates target/horn at Storage Area, II

1month 1year

50years 100years

high effective dose rates for the target/horn system makes them inaccessible for humans for years -> remote handling mandatory horn to be studied separately from the target results in agreement with older CERN’s 4MW beam studies, NIM A 545 (2005) 813-822

palette in mSv/h

> 50 mSv/h

> 0.01 mSv/h

> 1 Sv/h


Dose Equivalent Rate contribution (cooling time 1d)

0.000E+00

2.000E+10

4.000E+10

6.000E+10

8.000E+10

1.000E+11

1.200E+11

1.400E+11

1.600E+11

1.800E+11

0 20 40 60 80 100 120 140 160

All

Target

Horn

Vessel

Tunnel

89%

7% 4% 0%

Target

Horn

Vessel

Tunnel

Distance (cm) All Target Horn Vessel Tunnel*

60 554400 469800 38304 21722.4 82.152

100 240948 213660 15933.6 20746.8 3664.8

140 157716 123372 11300.4 18478.8 418.32

DER Estimation mSv/h

Fluka parameter Inputs : Proton Energy : 4.5 Gev Beam Intensity : 5.56*1015 protons Irradiation times : 200 days

First Step : 10000 Histories Second Step : 2000000 Histories

=> Increase statistics *Vessel act as a shield

DER Evolution with distance DER Contribution to the dose at 60cm


Activation in the rock around the SuperBeam layout(full 4horn simulation, medium stats: 106 protons, 20% error)

study set up: packed Ti target, 66%dTi

4MW beam, 4horns, 200days of irradiationaim: to confine the energy using concrete around the apparatus -> minimize the activation of the rock (molasse) minimum activation leads to minimum water contamination concrete thickness will determine the activation of the molasse of all the radionuclide's created 22 Na, tritium could represent a hazard by contaminating the ground water. Limits in activity after 1y=200days of beam:

CERN annual radionuclide release to water constraints (achieve 0.3mSv for the public)

SuperBeam, (preliminary)

22 Na 4.2 x 1011 Bq - (to be investigated)tritium 3.1 x 1015 Bq 6x108 Bq

activation plots


Activation and Energy Plots

molasse

concrete

molasse

concrete energy is confined from concrete thickness minimum activation of molasse rock minimum/none effective dose to humans in other galleries detailed tables of the radionuclides water contamination from tritium is well kept under safety levels

ACTIVITY in Bq/cm3

POWER in kW/cm3


ACTIVITY in Bq/cm3

ACTIVITY in Bq/cm3

with iron shield shield to protect service galleries additional cost

rock: molasse@CERN

concrete

Fe for shields, vessels and DT

graphite for beam dump

iron shields for service galleries


study set up: 4MW beam, packed Ti target, 66%dTi

4horns, 200days of irradiation

rates :A. at the start of the decay tunnel using a slice of beam/z-axis with 10cm

thicknessB. average dose rates along the beam/z-axis and x-axis(volume binning of 10cmx10cmx10cm on both cases)

shown from 1day to 6months, more cooling times and the effective dose along the layout are being simulated

Dose Rates in Target Horn Gallery

plots


Dose at the start of the Decay Tunnel in transversal x-y plane

1day 1month

4months 6months

> 10 Sv/h > 10 Sv/h

> 1 Sv/h> 1 Sv/h

palette in mSv/h


<Doses> in transversal and longitudinal planes for Target/Horn Gallery

palette in mSv/h

1month

1month

6months

6months

> 10 Sv/h > 1 Sv/h

> 10 Sv/h > 1 Sv/h

remote handling mandatory

x-y plane x-y plane

z-y plane z-y plane


<doses> in longitudinal plane along beam axis

palette in mSv/h

1day6months

1year 10years

DT areaHorns

Beam Dump

Horns

Horns

Horns

DT area DT area

DT area

Beam Dump

Beam Dump

Beam Dump


DT area

<doses> in longitudinal plane along beam axis

50years

100years

Horns Beam

Dump

Beam DumpHor

nsDT area

palette in mSv/h

highly effective doses drop after 50year or more4horn system with Ti highly activated and unapproachable for very long times as seen also in one horn example


summary

minimum activation in molasse rock for current secondary beam layout

tritium does not present any hazard related to ground water, 22 Na to be investigated (preliminary)

high dose rates in Storage Gallery -> remote handling for repairs mandatory high dose rates along SuperBeam layout -> carefully design of shielding for the apparatus, remote handling for any part of the 4horn system

costing increase

Thanks

Super Beam Simulation: radiation/activity, dose rates issues towards costing

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