EuCARD WP 7 – High Field MagnetsEuCARD WP 7 – High Field Magnets Task 2 – Support studies

Task 7.2 – Task 7.2 – Support StudySupport Study Status reportStatus report

EuCARD WP7 Collaboration Meeting – 18.09.2012 INFN-LASA Milano

Maciej Chorowski, Jaroslaw Polinski, Piotr Bogdan

Faculty of Mechanical and Power Engineering

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Outline

• Sample irradiation• Cryostat for electrical test• Mechanical tests• Thermal test at PWR• Task 7.2 planning

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Material burning during the irradiation

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Material burning during the irradiation

Pt 1000 sensor

1st possible reason: Lack of LN2 during irradiation?

The samples holder is equipped with Pt1000 T sensor. In case of temperature exceed 80K the accelerator control system stops the accelerator

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Material burning during the irradiation

2nd possible reason:

Heat deposited in the irradiated sample creates LN2 vapor bubbles around the heated area. Due of that the cooling capacity of the coolant drastically decrease and temperature of the sample increase over the material melting or flash point

Decision: reduction of the dose rate by 1/2 and see if the material is still burning for 50MGy of total dose

Beam

LN2

LN2 vapors

Irradiated sample

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Methods of the dose rate reduction

4s

6,67 ms

N electrons/s

4s

13,33 ms

2s

6,67 ms

N electrons/s

N electrons/s

4s

6,67 ms

1/2N electrons/s

Original beam scheme

Decrease of impulse frequency

Decrease of impulse time

Decrease of impulse intensity

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Material burning during the irradiation

Mix 71

Mix 237

LARP

Lonza CE

1st package – irradiated with 16 kGy/min 2nd package – irradiated with 10.8 kGy/min

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Irradiation plan prediction (based on the present irradiation procedure knowledge)

End

of

EuC

AR

D

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Toward to complete the irradiation certification program in the EuCARD time frame

• Determination/confirmation of the maximum dose rate which not cause the sample burning

• Change of thermal properties test method – thermal conductivity and heat capacity in 4-300K temperature range can

be determined on very small material sample by Institute of Low Temperature and Structure Research (ILTSR) in Wroclaw

– the samples for this tests can be extracted from the electrical or mechanical samples after them tests

– preparation of separated samples for the thermal tests, irradiated with 1 spot, can be considered

• Change of number of the irradiation spots on the mechanical samples from 4 to 1

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Patterns for thermal samples - 4 spots, d=17.5 mm

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Preliminary mechanical testsMech. sample preparation

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Preliminary mechanical testsMech. tests – irradiated samples

Burned Normal (Total dose: 0.5 – 0.7 MGy)

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Outline

• Sample irradiation• Cryostat for electrical test• Mechanical tests• Thermal test at PWR• Task 7.2 planning

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Electrical certification test cryostat

Voltage source – up to 60kV

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Electrical certification test cryostat stsus

• Cryostat was delivered at the end of August 2012

• Instrumentation - ongoing

• Commissioning, determination of the test procedure and first tests – mid. of Oct. 2012

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Outline

• Sample irradiation• Cryostat for electrical test• Mechanical tests• Thermal test at PWR• Task 7.2 planning

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Mechanical tests status

• Update of existing mechanical set-up with elements allow measurements in LN2 is undergoing in collaboration with PWR MechLab

• The possibility and quality of the mechanical sample cut-off with WaterJet technique will be tested next weeks

• The PWR MechLab has possibility to test the sample with Fourier Transform Infrared Spectroscopy (FTIS) and with Thermal Gravimetric Analysis (TGA), what can provide more information about the samples destruction origin (thermal/radiation)

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Outline

• Sample irradiation• Cryostat for electrical test• Mechanical tests• Thermal test at PWR• Task 7.2 planning

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Thermal tests – test parameters

• Material: unirradiated Mix 71 (NED insulation)• Thicknesses: 145.4 m, 253.7 m, 368.2 m, 501.8 m• Bath temperature levels: 1.5K, 1.55K, 1.6K. 1.7K, 1.8K,

1.9K, 2.0K, 2.1K• Dissipated heat range: 0÷125mW/sample = 0÷12 W/m2

• Heat step: 2mW• Heat step time: min. 4 min• Temperature increase range considered in post-test

analysis: 10÷35mK • Bath temperature stabilization: ±0.25mK

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Thermal tests – set-up view

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Thermal tests – test resultsThermal conductivity

0,02

0,025

0,03

0,035

0,04

0,045

1,5 1,6 1,7 1,8 1,9 2 2,1 2,2

Temperature

Th

erm

al c

on

du

ctiv

ity,

W/m

K

Meas 2012

NED equ.

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Thermal tests – test resultsKapitza resistance

0

0,0001

0,0002

0,0003

0,0004

0,0005

0,0006

0,0007

0,0008

1,5 1,6 1,7 1,8 1,9 2 2,1 2,2

Temperature

Kap

itza

Res

ista

nce

, m2K

/W

Meas 2012

NED equ.

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Outline

• Sample irradiation• Cryostat for electrical test• Mechanical tests• Thermal test at PWR• Task 7.2 planning

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WP7.2 Plan

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Summary

• The sample burning during irradiation has been found• Decrease of the irradiation dose rate from 16.0 to 10.8

kGy/min avoided this problem, nevertheless the max allowed dose rate need to be found/confirmed

• To keep the EuCARD time scale the modification in the thermal property certification test as well as in the mechanical and the thermal sample irradiation pattern is proposed

• Cryostat for electrical certification tests has been delivered and is currently under instrumentation on PWr. First certification tests are foreseen for mid of Oct.

• Preparation of the mechanical certification test in the LN2 conditions is ongoing

• Thermal conductivity and Kapitza resistance values of Mix 71 (NED) insulation has been confirmed on the PWr HEII cryostat experiment