Numerical Analysis of Feasibility of Beam Window for TEF ......Overview of TEF. 3 Conceptual design...

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Numerical Analysis of Feasibility of

Beam Window for TEF Target

Nuclear Transmutation Section, J-PARC Center, Japan Atomic Energy Agency

Hironari OBAYASHI Numerical analysis of feasibility of beam window for TEF target

Hironari OBAYASHI

Hayanori TAKEI, Hiroki IWAMOTO and Toshinobu SASA

Japan Atomic Energy Agency

2

Background and Purpose



◆ TEF-T(ADS Target Test Facility in Transmutation Experimental Facility)

has been planned to be constructed for practical use of ADS with LBE coolant

in J-PARC(Japan Proton Accelerator Research Complex).

Purpose:Development of the spallation target by the high

intensity proton beam and R&D of materials

Proton beam:

Beam energy 400 MeV – Power 250 kW

TEF: Transmutation Experimental Facility

PurposeSpecify the reference

condition for the target

at rated operation of

TEF-T

Model of target head

(installed horizontal direction)

proton beamOverview of TEF

3

Conceptual design of TEF target head



inner tube and lattice

and sample holder

g

slit

irradiation specimens ×8

lattice

• Beam Window(BW): concave shape

• Flow configuration: coaxially arranged annular tube type

• Sample holder: installed in the inner tube with 8 specimens

• Rectification Lattice: installed at the front-end of the sample holder, to cool

irradiation specimens uniformly

• Slit: arranged around the lattice, to cool the side of sample holder

proton beam

4

0

200

400

600

800

1000

1200

0 5

Case 1Case 2Case 3Case 4

hea

t p

ow

er

de

nsity [W

/cm

3]

distance of radial direction [cm]

These conditions of heat power density

profile including LBE were applied to

thermal-fluid & stress analysis.

Parameters of proton beam



Parameters of proton beam

Case 1 Case 2 Case 3 Case 4

Energy 400 MeV

Beam current 625 μA

Power 250 kW

Beam Shape Gaussian Flat top

Peak current density 20 μA/cm2 40 μA/cm2 60 μA/cm2 20 μA/cm2

•The same value was used for beam energy,

current, power in each case.

•Peak current were varied to improve annual

irradiation performance.

•Case 1-3 has Gaussian beam shape, Case 4

has Flat top which also has an advantage

for irradiation.

To define the reference beam condition

beam condition of actual ADS

(irradiation specimens of TEF:

7 dpa/4,500hr)

5

Analysis model and conditions



Thermal-fluid analysis: STAR-CD

Stress analysis: ABAQUS

Model 3D quarter type

Element hexahedral type

Turburent model k-ε for high Re num.

Material 316 SS

Thickness of BW 2 mm

Inlet flow rate 1 – 4 l/sec

Inlet LBE temp. 350 ℃

Beam profile Case 1 – 4

Peak current

density20, 40, 60 μA/cm2

Static pressure 0.3 MPa

Results of temperature profile data

•Surveyed the first target condition as a reference case by changing the flow rate & the

beam profile

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By considering the pump specification, the flow vibration and the acceleration of

erosion/corrosion, the max. velocity less than 2m/s is desirable.

Survey for Inlet flow rates (1,2,4 l/sec) by Velocity Profile

dead region

Max. velocity

dead region



• No specific gravity effect

was confirmed.

• The dead region was

formed along the center of

the BW, and the size was not

changed by changing the

flow rate.

• The size of the dead region

formed inside of the inner

tube was changed by the jet

flow which came from a slit.

• The maximum velocity was

observed at the region that

passed a lattice.

Flow rate of 1 or 2 l/sec are the candidates for TEF-T

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Survey for Beam Current Density by temperature profiles



Max.temperature: 596℃⊿T=90℃

In Case 2&3, the maximum temperature exceeded 500 ℃ and the

temperature difference exceeded 90 ℃

Case 2&3 were too severe condition for the material of the BW.

Case 1 set to the base beam injection condition

Analysis conditions

Material Thickness of BW Inlet flow rate Inlet LBE temp.

316 SS 2 mm 1 l/sec 350℃



⊿T: temperature difference of

outside & inside surface of

BW

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Additional analysis for Flat Top beam (Beam profile: Case 4)



The maximum temperature and the temperature difference were at the same

level as Case 1.

The temperature gradient was extremely large at the position of the beam edge.

Analysis conditions

Material 316 SS


Inlet flow rate 1 l/sec


Beam profile Case 4

Case 1:


Case 1

Merit of Flat top beam in comparison with Gaussian beam:

⇒ Mild temperature/irradiation slope in irradiation specimens

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Result of stress analysis (1)



EquationEvaluated

values

Acceptable

values

(2) 44 MPa 98 MPa

(3) 73 MPa 147 MPa

(4) 190 MPa 294 MPa

Pm:primary general membrane stress

Pb: primary bending stress

Q: secondary thermal-load stress

Sm: time-independent design stress strength

mm SP

mbm SPP 5.1

3m b mP P Q S

(2)

(3)

(4)

The stresses were lower than the

allowable level of the stress strength of

the material

Reference case

Material 316 SS


Inlet flow rate 1 l/sec


Beam profile Case 1

Static pressure 0.3 MPa

LBE flow

proton beam

Example of profile of “Tresca stress”

Max. Tresca stress

for the soundness of BW, following conditions

that should be satisfied

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Result of stress analysis (2)



Beam condition of TEF-T

(1st target as a reference case)

In Case 1 & Case 4, the stresses were lower than allowable level.

In Case 2, flow rate of 4 l/sec is required for the soundness of BW.

A feasibility of a designed BW was confirmed

with base beam injection condition.

located around beam edge

located at center of BW

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Summary



The reference case that was a first target condition in the

development of TEF-T was decided by our thermal-fluid and

stress analysis result.

Proton beam Intensity 400MeV - 250kW

Peak current density 20 mA/cm2

Beam profile Gaussian

LBE flow rate 1 l/sec

LBE Operation temp. 350 - 450℃

The soundness of the beam window was established.

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Future Works



In the nearly future works, some following analyses

will be performed.

The optimization of a beam shape and the

configuration of the flow channel

The inlet condition including the flow deflection

The verification of cooling performance for the

BW by the additional bypass jet flow

To get enough DPA value, the design of a target system for the repetition

of material irradiation is important.

13

Fin.



Thank you for your kind attention.

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Influence of thickness of BW (Beam profile: Case 1)



Max.temperature: 544℃ Max.temperature: 477℃

Analysis condition

Beam profile: Case 1

Inlet flow rate: 1 l/sec

Inlet LBE temp.: 350℃Material: 316 SS

The maximum temperature was observed at the center of the outside

surface of the BW, because of the formation of the dead region of LBE

flow.

Maximum temperature was reduced about 12% by decreasing the

thickness of the BW.

⊿T=65℃ ⊿T=37℃

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Heat generation density profile in TEF target system



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Construction Schedule (Tentative Plan)



• The construction of Beam line and TEF-T will be started in 2014 and the operation with 1/4 beam power will be started in 2017

• To start the construction of TEF-P in 2017, just after the completion of TEF-T, a few years of licensing activities should be started in 2015

Fiscal Year 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024

Beamline

TEF-T

TEF-P Construction

Operation

Licensing

R&D, Design

Construction

Operation

R&D, Design

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Construction Budget (Tentative Plan)



YearCost (M$)

Sum 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024

R&D 8.9 1.0 2.1 2.9 2.9

ADS-BT 17.3 8.6 8.7

TEF-T 64.1 22.5 22.6 19.0

TEF-P 129.4 12.6 29.2 29.2 29.2 29.2

Total 219.7 1.0 2.1 34.0 34.2 31.6 29.2 29.2 29.2 29.2

Budget for 2013 is not directly related to construction but it includes1) TEF design,

2) Construction of mockup for LBE spallation target loop,

3) Laser source preparation, and

4) Survey for MA fuel preparation

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Sample irradiation amount



200

300

400

500

600

700

800

900

1000

0

10

20

30

40

50

60

20 30 40 50 60

He P

rod

uctio

n (H

e a

pp

m/y

ea

r)D

PA

(1/y

ea

r)

Proton Beam Current Density (mA/cm2)

DPA/y DPA/y (ADS) He appm/y He appm/y(ADS)

Max. Beam Current Density

• Higher irradiation amount can be obtained by increasing beam density

• To simulate full scale ADS window, it requires 3-5 cycles of full power

irradiation

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Temperature and irradiation in specimens



• Case 4 shows flat DPA distribution and easy to take irradiation test pieces

• Similar profile is seen for He production distribution

• Sample temperature deeply depends on coolant flow conditions

Case 1:Reference Case 4:Flattop

0

6

12

DPA（DPA/year）

0

250

500He Production （He appm/year）

350˚C

400˚C

500˚C

600˚CTemperature

Date post:	10-Jun-2020
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Numerical Analysis of Feasibility of Beam Window for TEF ......Overview of TEF. 3 Conceptual design...

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