bene week, cern, switzerlandy.kadimarch 16-19, 2005 1 multi-mw target development for eurisol &...

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BENE Week, CERN, Switzerland Y.KADI March 16-19, 2005

MULTI-MW TARGET DEVELOPMENT FOR

EURISOL & EUROTRANS

Y. Kadi & A. Herrera-Martinez(AB/ATB)

European Organization for Nuclear Research, CERNCH-1211 Geneva 23, SWITZERLAND

[email protected]

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Multi-MW Target Challenges

• High-Power issues– Thermal management

• Target melting• Target vaporization

– Radiation• Radiation protection • Radioactivity inventory• Remote handling

– Thermal shock• Beam-induced pressure waves

– Material properties

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Thermal Management: Liquid Target with window

The SNS Mercury Target H

arol

d G

. Kirk

et a

l. (B

NL)

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Thermal Management: Liquid Target with window

F. G

roes

chel

et a

l. (P

SI)

• MEGAPIE Project at PSI

• 0.59 GeV proton beam

• 1 MW beam power• Goals:• Demonstrate

feasablility• One year service life• Irradiation in 2005

Proton Beam

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Thermal Management: Liquid Target with windowF

. Gro

esch

el e

t al.

(PS

I)

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Thermal Management: Liquid Target with free surface

High-speed flow (2.5 m/s) permits effective heat removal

BEAMDG16.5 Hg Experiments nominal volume flow 10 l/s

Close to desired configuration intermediate lowering of level some pitting axial asymmetry

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Thermal Management: Target Pitting Issue

FeatureNormalized

Erosion*Gas layer near surface 0.06Bubble Injection 0.25Kolsterized surface 0.00081/2 Reference Power 0.09* Erosion relative to reference (2.5 MW) case

ESS team has been pursuing the Bubble injection solution. SNS team has focused on Kolsterizing (nitriding) of the surface solution. SNS team feels that the Kolsterized surface mitigates the pitting to a level to make it marginally acceptable. Further R&D is being pursued.

After 100 pulses at 2.5 MW equivalent intensity

Before

Har

old

G. K

irk e

t al.

(BN

L)

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Worldwide Programs

Project Neutron Source Core Purpose

MUSE(France)

DT(~1010n/s)

Fast(< 1 kW)

Reactor physics of fast subcritical system

TRADE(Italy)

Proton (140 MeV)+ Ta (40 kW)

Thermal(200 kW)

Demonstration of ADS with thermal feedback

TEF-P(Japan)

Proton (600 MeV)+ Pb-Bi (10W, ~1012n/s)

Fast(< 1 kW)

Coupling of fast subcritical system with spallation source including MA fueled configuration

SAD(Russia)

Proton (660 MeV)+ Pb-Bi (1 kW)

Fast(20 kW)

Coupling of fast subcritical system with spallation source

MYRRHA(Belgium)

Proton (350 MeV)+ Pb-Bi (1.75 MW)

Fast(35 MW)

Experimental ADS

MEGAPIE(Switzerland)

Proton (600 MeV)+ Pb-Bi (1MW)

----- Demonstration of 1MW target for short period

TEF-T(Japan)

Proton (600 MeV)+ Pb-Bi (200 kW)

-----Dedicated facility for demonstration and accumulation of material data base for long term

Reference ADSProton ( ≈ 1 GeV)

+ Pb-Bi (≈ 10 MW)Fast

(1500 MW)Transmutation of MA and LLFP

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Thermal Management: radiation cooled rotating toroidal target

toroid at 2300 K radiates heat to water-cooled surroundings

rotating toroid

proton beam

solenoid magnet

toroid magnetically levitated and driven by linear motors

R.B

enne

tt, B

.Kin

g et

al.

• Distribute the energy deposition over a larger volume• Similar a rotating anode of a X-ray tube

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Thermal Management: JET

Double enclosedSS - Hg loopwith windows

Remote controlledLaser optics andhigh speed video

recording

Mobile coil magnetwith viewing space

(15 cm)

24 GeVproton beam20-50 pulses

Nufact Hg-jet target experimentin the N-ToF tunnel

classical, no sliding mirrors

Pulsed Hg pump~ 15 kg/s

P-beamwindow

Beam profileand positionmonitoring

x-y-z- ? alignment ?system

Mirrors2 + 2 fixed mobiles

J.Lettry et al. (CERN)TT2A

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Radiation Management

The SNS Target Station

Core Vessel water cooled shielding

Core Vessel Multi-channel neutron guide flange

Outer Reflector Plug

Target Inflatable seal

Target Module with jumpers

Moderators

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The JPARC Kaon Target

Concreteshield

Concreteshield block

Service space:2m(W)1m(H)

Beam

~10m

~18m

T1 containerIron shield 2m

Waterpump

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Objectives

The objective is to perform the technical preparative work and demonstration of principle for a high power target station for production of beams of fission fragments using the mercury proton to neutron converter-target and cooling technology similar to those under development by the spallation neutron sources, accelerator driven systems and the neutrino factories.

This high power target that will make use of innovative concepts of advanced design can only be done in a common effort of several European Laboratories within the three communities and their proposed design studies.

In this study emphasis is put on the most EURISOL specific part a compact window or windowless liquid-metal converter-target itself while the high power design of a number of other more conventional aspects are taken from the studies in the other EURISOL tasks or even in other networks like ADVICES, IP-EUROTRANS.

EURISOL – Multi-MW Target

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• 3x100 kW direct irradiation• Fissile target surrounding a spallation n-source

– >100 kW Solid converters (PSI-SINQ 740 kW on Pb, 570 MeV 1.3 mA / RAL-ISIS 160 kW on Ta, 800 MeV 0.2 mA / LANL-LANSCE 800 kW on SS cladded W, 800 MeV 1.0 mA )

– 4 MW Liquid Hg (windowless or jet)

EURISOL Target Stations

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1-3 GeVproton beam(ms pulses)

dc Hg-pump~ 15 m/s

Hg-tank

Reflector

Transfer line to the ion-source

UC2 target material

Ta-target container

Heat screens

Hg-filled SS tube or free Hg jet

Moderator

60 kV 60 kV > 2000º

Grounded< 200º

EURISOL Hg-converter and 238UC2 target

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P4 – CERN

P18 – PSI Switzerland

P19 – IPUL Latvia

C5 – ORNL USA

Participants Contributor


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0

4

8

12

16

CERN PSI IPUL

Staff FTE

Available

Req. Contr.

EU-funding 828 kEuros

CERN

PSI

IPUL

HR

MaterialTravel


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Description of work

The task will be accomplishment through detailed engineering and theoretical work, off line and on-line testing of the different subsystems as seen from the following 5 subtasks:

Engineering study of the thermal hydraulics, fluid dynamics and construction materials of a liquid-metal converter (window/windowless or jet);

Study of an innovative waste management in the liquid Hg-loop e.g. by means of Hg distillation;

Engineering design and construction of a functional Hg-loop;Off-line testing and validation of the thermal hydraulics and fluid

dynamics;Engineering design of the entire target station and its handling

method.


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Main goals for the first 12-15 months

Provide a first technical design of the liquid Hg proton-to-neutron converter

Provide a status report on optimum method for continuous extraction of radioisotopes

Provide a preliminary engineering design and cost evaluation of the liquid Hg test loop

Initiate technical study on the integration of the entire target station


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Engineering Study of the liquid metal converter

Definition of the main parameters (neutron flux angular and energy distributions, radiation damage, heat deposition, spallation product distributions) as a function of energy (1 – 3 GeV) and type of incident particle (p or d)

Establishment of the operation modes (Hg flow rates, cavitation limits, thermo-mechanical behaviour of the structures under normal operating conditions) Evaluation of the feasibility of a windowless configuration

Breakdown of work (per sub-task)

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• Projectile Particle: Proton

• Beam Shape: Gaussian, ~1.7 mm

• Energy Range: 1–2–3 GeV

• Target Material: Hg / PbBi

• Target Length: 40–60–80–100 cm

• Target Radius: 10–20–30–40 cm

• Spatial and energy particle distribution

Preliminary Studies

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1 GeV Proton range ~46 cm

• The beam opens up to ~20 degrees, with some primary back-scattering

• Primaries contained in ~50 cm length and ~30 cm radius

1x10-9

1x10-8

1x10-7

1x10-6

1x10-5

1x10-4

1x10-3

0.01 0.1 1

Primary flux (dn/cm2/dlnE/prim)

Energy (GeV)

1 GeV Primary Proton Flux

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• Maximum energy deposition in the first ~14 cm in the beam axis beyond the interaction point, ~30 kW/cm3/MW of beam dT/dt ~14 K/s (Hg boiling point at 357 ºC)

• Energy deposition drops one order of magnitude at the proton range (~46 cm)

• Large radial gradients (dE/dr ~200) in the interaction region

Energy Deposition for 1 GeV protons

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• Neutron flux centered radially around ~10 cm from the impact point

• Isotropic flux after ~15 cm from the center, decreasing with r2

• Escaping neutron flux peaking at ~300 keV (evaporation neutrons), with a 100 MeV component in the forward direction (direct knock-out neutrons)

1x10-9

1x10-8

1x10-7

1x10-6

1x10-5

1x10-4

1x10-3

0.0001 0.001 0.01 0.1 1 10 100 1000

Neutron flux (dn/cm2/dlnE/prim)

Energy (MeV)

Radial

End Cap

Front Cap

Radial

End Cap

Front Cap

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30

31

32

33

34

35

36

20 22 24 26 28 30 32 34 36 38 40

Neutron yield (neutron/primary)

Radius (cm)

Target length: 60 cm



Neutron Flux Distribution for 1 GeV Protons

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1x10-9

1x10-8

1x10-7

1x10-6

1x10-5

1x10-4

1x10-3

0.0001 0.001 0.01 0.1 1 10 100 1000


Energy (MeV)

Radial

End Cap

Front Cap

238U Fission Cross Section

0

0.5

1

1.5

2

2.5

5 15 25 35 45 55 65 75 85 95 105

Energy (MeV)

Sigma (Barn)neutron

proton

deuteron

1x10-11

1x10-10

1x10-9

1x10-8

1x10-7

1x10-6

1x10-5

1x10-4

1x10-3

1x10-2

1x10-1

1x100

1x101

1x102

1x103

1x10-8 1x10-7 1x10-6 1x10-5 1x10-4 1x10-3 1x10-2 1x10-1 1x100 1x101 1x102

fission cross-section (barn)

Energy (MeV)

Fission in U238

Fission in U235

• Very low fission cross-section in 238U below 2 MeV (~10-4 barns). Optimum neutron energy: 35 MeV

• Alternatively, use of natural uranium: fission cross-section in 235U (0.7% wt.) for 300 keV neutrons: ~2 barns

• Further gain if neutron flux is moderated

Neutron Energy Spectrum vs Fission Cross-Section in Uranium

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ProtonsHg Target

UCx Target

UCx Target

Standard Configuration

ProtonsHg Target

Reflector / UCx Target

Alternative Configurations


Low-Z Filter (?)UCx

Target

1x10-9

1x10-8

1x10-7

1x10-6

1x10-5

1x10-4

1x10-3

1x10-2

0.0001 0.001 0.01 0.1 1 10 100 1000


Energy (MeV)

length: 40 cm

length: 60 cm

length: 80 cm

Reflector?

Reflector?

Alternative Target Configurations

Deuterons

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ProtonsHg Target


Alternative Configurations


Low-Z Filter (?)UCx

Target

1x10-8

1x10-7

1x10-6

1x10-5

1x10-4

1x10-3

1 10 100 1000

Proton flux (dp/cm2/dlnE/prim)

Energy (MeV)

length: 60 cm

length: 80 cm

• Increasing HE neutron flux through the End-Cap with decreasing Hg target length

• Increasing charged-particle and photon escapes with decreasing Hg target length

• Possible use of a low-Z filter to “tune” the average neutron energy to 35 MeV (maximise fission probability in 238U) 1x10-8

1x10-7

1x10-6

1x10-5

1x10-4

1x10-3

0.01 0.1 1 10 100 1000

Photon flux (dg/cm2/dlnE/prim)

Energy (MeV)

Alternative Target Configurations

Deuterons

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•Neutron absorbing region ~6 cm behind the interaction region, following the primary particle distribution

• Neutron producing region extending to the end of the target

• Small contributions from regions beyond the proton range

• Neutron producing region not extending beyond r =10–13 cm

Neutron absorbing

region

Neutron producing region

Neutral balance

boundary

Neutron Balance Density for 1 GeV Protons

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• Forward peaked primary distribution at ~10 degrees

• No back-scattering and rare radial escapes

• Few end-cap escapes:

210-3 escapes/primary with an average energy of 1 GeV for 80 cm

2 10-5 escapes/primary with an average energy of 0.7 GeV for 100 cm


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• Largest energy deposition in the first ~18 cm beyond the interaction point, ~16 kW/cm3/MW of beam dT/dt ~8 K/s (40% lower compared to the use of 1 GeV primary protons)

• Identically, smaller radial gradient in the interaction region (dE/dr ~100)


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Neutron Yield (2 GeV proton) : 57 – 77 n/p

1x10-8

1x10-7

1x10-6

1x10-5

1x10-4

1x10-3

1x10-2

0.0001 0.001 0.01 0.1 1 10 100 1000 10000


Energy (MeV)

Radial

End Cap

Front Cap

• Neutron flux centered radially around ~15 cm from the impact point, presenting a forward-peaked component

• Escaping neutron flux peaking at ~300 keV, with a 100 MeV component in the forward and radial directions and few 1 GeV neutrons escaping through the end-cap

• Harder neutron energy spectrum and higher flux and in the target compared to the 1 GeV case

1x10-8

1x10-7

1x10-6

1x10-5

1x10-4

1x10-3

1x10-2

1x10-1

0.0001 0.001 0.01 0.1 1 10 100 1000 10000


Energy (MeV)

1 GeV

2 GeV


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• Increase in the relevance of the axial region in the neutron production

• Neutron producing region still not extending beyond r =10 – 13 cm

• The neutron capturing region gains relevance (–610-4 bal/cm3/prim) compared to 1 GeV (–610-5 bal/cm3/prim)

• Significant reduction in neutron captures (one order of magnitude) by reducing the radius to 20 cm

Neutron absorbing region


Neutral balance

boundary

Neutron Balance Density for 2 GeV Protons

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• The beam opens up to ~8 degrees, no back-scattering and few radial escapes (even for 20 cm radius)

• Some primaries escapes through the end-cap (~ 5 10-5 escapes/primary)

• Average energy of the escaping protons ~750 MeV

1x10-8

1x10-7

1x10-6

1x10-5

1x10-4

1 10 100 1000 10000

Proton flux (dp/cm2/dlnE/prim)

Energy (MeV)


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• Largest energy deposition in the first ~22 cm beyond the interaction point, ~12 kW/cm3/MW of beam dT/dt ~6 K/s (60% lower compared to the use of 1 GeV primary protons)

• Smaller radial gradient in the interaction region (dE/dr ~50) compared to the 1 GeV case


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Neutron Yield (3 GeV proton) : 82 – 113 n/p

• Neutron flux centered radially around ~20 cm from the impact point, with a larger forward-peaked component

• Escaping neutron flux peaking at ~300 keV, with a 100 MeV component in the forward and radial directions and some 1.5 GeV neutrons escaping through the end-cap

• Slightly higher neutron flux in the target compared to the 2 GeV case

1x10-8

1x10-7

1x10-6

1x10-5

1x10-4

1x10-3

1x10-2

0.0001 0.001 0.01 0.1 1 10 100 1000 10000


Energy (MeV)

Radial

End Cap

Front Cap

1x10-8

1x10-7

1x10-6

1x10-5

1x10-4

1x10-3

1x10-2

1x10-1

0.0001 0.001 0.01 0.1 1 10 100 1000 10000


Energy (MeV)

2 GeV

3 GeV


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Hg

PbBi

1 GeV proton range in Hg: ~46 cm

1 GeV proton range in PbBi: ~60 cm

PbBi Alternative – 1 GeV Primary Particles

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Hg

PbBi

Maximum energy deposition ~30 kW/cm3/MW of beam

Maximum energy deposition ~21 kW/cm3/MW of beam

PbBi Alternative – Energy Deposition

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Hg

PbBi

PbBi Alternative – Neutron Flux

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PbBi

Hg

Neutron absorbing region Neutral

balance boundary



PbBi Alternative – Neutron Balance

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PbBi Alternative – Neutron Spectrum

1x10-8

1x10-7

1x10-6

1x10-5

1x10-4

1x10-3

1x10-2

1x10-5 1x10-4 1x10-3 1x10-2 1x10-1 1x100 1x101 1x102 1x103


Energy (MeV)

Hg Target 10 cm Rad

PbBi Target 10 cm Rad

Hg Target 40 cm Rad

PbBi Target 40 cm Rad

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• Optimised for neutron production:

• Radius: 10 – 15 cm target radius from neutron balance point of view is enough

• Length: Extend to the proton range to maximise neutron production and avoid charged particles in the UCx

• Energy Spectrum of the neutrons:

Dominated by the intermediate neutron energy range ( 20 keV - 2 MeV)

Harden neutron spectrum by reducing the target size (but reduce yield and increase HE charged particle contamination)

Use of natural uranium to take advantage of the high fission cross-section of 235U in the resonance region Improvement thorough neutron energy moderation

Alternatively, axial converter-UCx target configuration for depleted uranium target

• Very localised energy deposition, 20 cm from the impact point along the beam axis ~30 kW/cm3/MW of beam power, reduced with the increasing proton energy

• Possibility of using PbBi eutectic to improve neutron economy and reduce maximum energy deposition

Summary of the Results

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• Optimise the energy deposition once the size is fixed

Study the effect of the shape of the beam (parabolic, annular, variations in the

sigma of the Gaussian distribution)

• Activation of the target (calculate the spallation product distribution)

• Model the fission target (including moderator/reflector) and optimise the fission yields

• Analyse alternative target disposition to improve the fission yields

• Study the use of deuterons as projectile particle

Future Work

bene week, cern, switzerlandy.kadimarch 16-19, 2005 1 multi-mw target development for eurisol &...

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