First SHIP Workshop – 10-12 June 2014 - Zurich
Design and challenges for
the SHIP target complex
M. Calviani, A. Ferrari, R. Losito, A. Perillo-Marcone, R.
Folch, V. Venturi
Engineering Department (EN)
Sources, Targets and Interactions (STI) Group
Outline

SHIP target station design


SHIP production target


Preliminary thoughts and challenges
Issues and present conception
Conclusions and perspectives
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M. Calviani - Design and challenges for
the SHIP target complex
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Target areas at CERN

CERN target areas are generally halls, pits or long
tunnels, far from the access points


Activated air has enough time to decay and stray radiation
is not a problem for the public
Neutrino ones are generally deep in the molasses (e.g.
CNGS)
Antiproton target
WANF & CNGS
n_TOF (neutrons)
TCC2
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SHIP target station design





The SHIP TS
preliminary
Due to thedesign
shallow depth of the beam line
takes
(~14 advantage
meters), a of
target area approach based
the
for CENF
on activities
long tunnels
(i.e. CNGS, WANF, etc.) is
Shallow
target
not applicable
installation, multiA
multi-compartment
solution
similar
to
compartment solution
T2K/NuMI has been therefore developed,
Underground areas
taking into account the specificities of CERN
accessible from the
target hall
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the SHIP target complex
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Features of the SHIP target station

Production target installed inside an
underground Fe shielded bunker,
accessible from the top
Iron
shielding to
be water
cooled
(~O(100 kW))
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Features of the target station

Fully remote handling/manipulation of the
target and shielding from the target hall


Helium environment enclosing the target and
the shielding


High residual dose rate (~tens of Sv/h!)
Reduction of air activation and corrosion
Ventilation system according to ISO17874

The idea is to have a pressure  dynamic
confinement
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the SHIP target complex
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M. Battistin (EN/CV)
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
Target hall above ground level

Outside area shall be non-designated during target
manipulation
 Ground-filled around target hall or heavy concrete walls

An additional (smaller) service building needed

Safety racks, EL cabinets (EBD, etc.), transformers,
water treatment area, access, etc.
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M. Calviani - Design and challenges for
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View of the
target hall and
service
buildings
Access for transport and
various additional services
(EL, secondary water loops,
etc.)
35 m
Radioactive
areas,
accessible in
shutdown
Radioactive
areas, no access
38 m
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Target station summary


Target station shall be designed for a MWclass spallation target
Specific attention to radioprotection &
environmental releases – well mastered and
evaluated for CENF but feasible
Challenging…

CE works adapted to minimize water infiltration
and in case treatment with evaporators

Shall be designed for long-term operation
 Minimize time for target exchange in case of
failure (physics downtime)
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Target design

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The production target is the single most
critical aspect of the target complex
As required by the experiment, W-based (i.e.
high-Z) target
Long term reliability is a key factor in the
design
Reduction of “waste”
 Reduce downtime to minimum

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(Spallation) source

One of the most technologically challenging
aspects of the proposed installation

Beam parameters

In terms of average beam power on target would be
similar to SNS (USA) or MLF (JP)
However, power during pulse would make it closer to
ESS (almost 3 MW)
Beam
Momentum [GeV/c]
Beam Intensity [1013 p/cycle]
Cycle length [s]
Spill duration [s]
Expected r.m.s. spot size (H/V) [mm]
Average beam power on target [kW]
Average beam power on target during spill [kW]
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Baseline
protons
400
4.5
7.2
1.0
6/6
400
2900
Ultimate
protons
400
7.0
8.4
2.2
6/6
530
2030
M. Calviani - Design and challenges for
the SHIP target complex
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Analysis method
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Analysis assumes nominal operation, with
both the baseline and ultimate beams

Steady state with transient analysis
 Worst case scenario, i.e. target reaches steady
state and then receives a high intensity pulse

Main preliminary results:

Full W cylinder will not withstand the
compressive stresses (>2 GPa) and
temperatures (>1200 °C) – target would fail
 Target segmentation mandatory to allow
decrease of temperatures and thus stresses
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Energy deposition and checks

FLUKA/ANSYS/CFX
coupled calculations



Pure tungsten, 19.3
g/cm3
60 cm length, 20x20 cm2
Beam on target:
Uniform circular sweep 3
cm radius, 1s 6 mm
2. Archimedean spiral, 5-35
mm radius (1s 6 mm)
1.

80% energy deposited in
the target (300-400 kW)
Target must be actively cooled
(H2O considered for the
moment) 11th June 2014
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the SHIP target complex
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
Optimisation of the
plate thickness still
ongoing
 Longitudinal gap of
~O(10-15 cm)
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Peripheral + radial
cooling to increase
HTC
M. Calviani - Design and challenges for
tangential velocities
the SHIP target (5-10
complex m/s)!
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Thermo mechanical calculations

Considering the poor properties of W heavy
alloys to high temperature and radiation we
baselined pure W
 ~780 °C, 900 MPa (worst case)
 R&D needed!!!

Caveat:


Conservative
assumptions
Still lots of margins
for improvement!
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Accident scenario (no sweep)
3000 °C (below melting
point at ~3400 °C)
~4.4 GPa compressive
stress
The target would not melt... But will fail!
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Radiation damage

Design shall assume that a target withstands the
whole proposed POTs (2*1020)
 ~1.2 DPA (displacement per atom) at 2*1020 POT

Big impact on the evolution of mechanical properties!
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Evolution of mechanical properties
with radiation (and temperature)
Yield stress increases with
irradiation and decreases
with temperature
Reduction of ductility
with irradiation
S. A. Maloy et al., ICANSXX workshop (2012)
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S. A. Maloy, Materials
Transactions, Vol. 43, No. 4
(2002)
M. Calviani - Design and challenges for
the SHIP target complex
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Crack formation on pure W
samples under irradiation
S. A. Maloy et al., ICANSXX
workshop (2012)
S.A. Maloy et al. / Journal of Nuclear
Materials 343 (2005) 219–226
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The central core of the SHIP
target might potentially develop
internal cracks due to radiation
embrittlement, swelling and high
M. Calviani - Design and challenges for
temperature
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the SHIP target complex
Target design preliminary
assessment

The target must be segmented to reduce
temperatures and compressive stresses
 Very high flow rate required (cavitation,
erosion/corrosion...)

Need to check “water hammer” effect on target/cooling
circuits

Full control of water chemistry (à-la-n_TOF)
 Vigorous R&D should be launched on material
properties and their evolution with radiation and
temperature

Ta-cladded W, WRe alloys, K-doped W alloys, etc.
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Possible other uses?

We are considering a 500 kW (3 MW
pulsed) class spallation source
 Possible additional uses with minor
additional investments:

Neutron/photon irradiation close to the target
 ~100-200 MGy/y lateral, 400 MGy/y downstream

Neutron beam(s) for different applications (i.e.
neutron radiography) laterally outside of the He
vessel (@500 cm or more)
 …
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Conclusions


Target design is very challenging (but
feasible!), significant R&D required on
material and technical work for CFD and
code optimization
Target station design needs to account the
high average power (hence radioprotection
and handling aspects)

Profit from CENF studies but a dedicated WG
will be needed towards the DR
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the SHIP target complex
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BACKUP
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the SHIP target complex
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the SHIP target complex
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