12th ITPA TG Meeting on Diagnostics 26 - 30th March 07, Princeton Radiation Effects WG Benoit Brichard for Eric Hodgson Last meeting of Radiation Experts.

12th ITPA TG Meeting on Diagnostics26 - 30th March 07, Princeton

Radiation Effects WG Benoit Brichard for Eric Hodgson

• Last meeting of Radiation Experts at 16th IEA Workshop held during SOFT-24 (13th Sept 06) in Warsaw.

• 21 people attended the 5 h meeting - (EU:15, JA:3, EFDA:2, ITER:1)unfortunately no RF or US colleagues.

• Updates given on activities:JA (M. Yamauchi) EU / RF / US (E. Hodgson)Extended presentations on:TIEMF / RIEMF (R. Vila and L. Vermeeren)Optical fibres (B. Brichard)Common issues for Magnetic and Inertial Confinement (J.L. Bourgade, M. Decreton, E. Hodgson)

Radiation R&D requirements for diagnostics - table update (G. Vayakis)

• Following is a summary of the presentations + recent work/results ==>

EU

Optical fibres (Belgium, France, Rumania): Benoit Brichard (separate presentation)

Resistance type bolometers (Belgium, Germany, Spain):

Pt on 3 different substrates: alumina, AlN, “SiN” to be irradiated in BR2, SCK/CEN

General electrical contact problem* being addressed

Ferroelectric type bolometers (Austria, Latvia, Spain):

PbZrO3 with reliable electrical contacts* being prepared - but long delay

Hall sensors (IPP:CR + Ukraine):

New sensors based on solid solutions of InSb and InAs potential for > 200°C

But problems with electrical connections*, solder joints, thin wire insulation

Reactor irradiation later this year

*Electrical contacts for small devices / components giving problems during irradiation

EU

Plan to test various cable types for RIEMF/TIEMF effects with active heating, so a new rig design isnecessary. Should give a clue on the performances of various types of MI cables (stainless steel vs.copper core; size effect; single-core vs. twin-core) and of ceramic coated wires and twisted-pair Sultzercable (OFC). Awaiting cable delivery

Twisted Sultzer cableØ3.5mm

in tube Ø4/5mm

Twin core MI cable (Cu-SS)Ø3.2mm

Single-core MI cable (Cu-SS)Ø1.5mm

Single-core MI cable (Cu-SS)Ø1.0mm

Ø0.8mm ceramic coated wires (Cu-SS) in tubes Ø1/2mm

Thermocouples

Fillers

Coiled Ø1.5mm

heating wires

SS tubes Ø13/16

and Ø18/22

Gas gap

EU

RIEMF and TIEMF in MI cables and cables (Belgium, Spain):

TIEMF (centre conductor) detailed studyExamine EMF (V) vs T for Cu, Ni, and SS cored cables

Will need some standard “QA” test (e.g. TIEMF for fixed temperature gradient over 1 m)

Large EMFCu related to damage to soft Cu conductor during manufacture - probably no solution Probable cause of high EMF for Ni core also ==> use SS or twisted ceramic coated cables ?

Severe damage in Cu Incrusted silica

EU

Alternative radiation resistant glasses (Belgium, Spain):

Tests with Na2O-CaO-SiO2 (+ CeO2) glasses. Radiation induced absorption and RL≥ 200 ºC shows much lower absorption:

Na2O-CaO-SiO2 glass

Absorption 0.5 MGy, 70ºC Absorption 0.6 MGy, 200ºC

-1.0

0.0

1.0

2.0

3.0

4.0

5.0

200 400 600 800 1000Wavelength, nm

Indu

ced

Abs

., 1/

cm

R1-2d R1-2e R1-2f R1-2g R1-3c

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0.30

200 400 600 800 1000Wavelength, nm

Indu

ced

Abs

., 1/

cm

R1-1b R1-1c R1-1d

EU

Alternative radiation resistant glasses (Belgium, Spain):

Absorption recovers at RT following irradiation ==> unstable defects need in-situ measurements

RL (and absorption) is intense in both glasses compared with KU1 and KS-4V:Now preparing RL measurements at high T (≤ 250 C)

Absorption 0.2 MGy, 20ºC Radioluminescence, 20ºC

0510152025

300040005000600070008000

OD

(cm

-1)

Wavelength (Å)

214 kGy (Just after irradiation)214 kGy(15 hours later)

0

0.05

0.1

0.15

0.2

0.25

2000 2500 3000 3500 4000 4500 5000 5500 6000

RL

(a

.u.)

Wavelength (Å)

KU1

(Ce doped)

Undoped

EU

Windows, ceramics, mirrors (Spain):

Enhanced surface degradation (optical and electrical) by low energy H and He bombardment.XPS analysis shows extreme O sputtering loss for silicas and aluminasResults => Si or Al rich surface zone Potential problem ?

Ion conductivity at low residual gas (He, H) pressures (Spain):

Necessary to determine potential currents - measure RIC at low pressure => pA/cc/Gy at 10 -3mbar

0

2

4

6

8

10

12

14

16

0.5 1 1.5 2

Energy (keV)

Si

O

Unimplanted

450ºC

250ºC

50 ºC

EUSecondary overcoated mirrors (Spain):

UV enhanced mirrors degrade - radiationmodification of coating (thickness, refr. index)

Manufacturers specifications not always reliable:

HfO2 for MgF2 ==> activation ?

SiO / SiO2 ratio ==> swelling cracking corrosion (LOCA)

JA(M. Yamauchi, T. Shikama, S. Nagata, K. Toh, B. Tsuchiya, A.Inouye)

1. RL (Radiation induced luminescence):

Fused silica, Cr doped sapphire, and Eu and Dy doped strontium aluminates

gamma-ray, ion, and 14 MeV neutron irradiation.

Aim to separate ionization and displacement dose effects. RL as sensor for 14 MeV neutrons.

Possibility of monitoring ion energy has been demonstrated (Cr in sapphire).

0.0 1.0 2.0 3.0

1011

1012

0.3MeV

0.5MeV

1.0MeV

1.5MeV

R-li

ne

lum

ines

cenc

e yi

eld

s [ c

ps /

curr

ent ]

Fluence [ 1019 ions / m2 ]

JA

2. Conversion of nuclear radiation energy directly into electricity:

RIC is being studied in perovskite oxides with high proton conductivity.Neutron irradiation enhances proton conductivity even at low temperatures (20-200 C). Importance of hydrogen in radiation effects in oxide ceramics.May cause technological problems in nuclear fusion machines, so far not considered.

10-9

10-8

10-7

10-6

10-5

10-4

10-3

10-2

0.0 0.5 1.0 1.5 2.0

with Hwithout Hwithout H

Ionizing Dose Rate (kGy/s)

BaCe0.9Y0.1O3-

Conductivity (S/m)

first cycle(a)

JA

3. Large EMF in proton conductors (CaZrInO) :

Large EMFs observed in some proton conductors ionizing dose rate (monitor ?)Not the case in other similar materials (SrCeYbO)

RF(Ilya Orlovskiy and Konstantin Vukolov)

Development of multilayer dielectric mirrors: heating and neutron irradiation

Thermal loads play important role in damaging mirror coating.Sufficient adhesion of coating to substrate for large size mirrors. Sustain neutron fluences and temperatures expected in ITER (0.01 dpa little effect), shift to shorter

Luch mirrorZrO2 / SiO2

RF

Recent multilayer dielectric mirrors: heating and neutron irradiation

TiO2/SiO2 23 layers KU1 and K8 substrates - stable under thermal loading

RF

Multilayer dielectric mirrors: heating tests

Stable under thermal loading repeated heating in vacuum to T ≤ 300 C for times up to 10 hCoatings undamaged, initially range shifts to longer , then stable

US(K. Leonard, R. Goulding, L. Snead and S. Zinkle)

Post irradiation loss measurements at 100 MHz in ceramics for ICRH:

Single crystal sapphire and spinel show lowest initial losses, but by 0.001 dpa all oxides

similar (possible problem with Deranox sample). BeO almost insensitive. Nitrides worse.

1.0E-06

1.0E-05

1.0E-04

1.0E-03

1.0E-02

Al2O3(99.5%)

Sapphire Spinel BeO Si3N4 AlN(98.5%)

AlN(94%+Y)

Al2O3 (99.9%) Deranox

Ta

n

control0.001 dpa0.01 dpa0.1 dpa

US

For oxides little change from 0.001 to 0.1 dpa - importance of ionization at onset

Important to remember PIE, and low T (≈ 65C) irradiation in water - not vacuum or He

US

Post irradiation thermal conductivity measurements in ceramics for ICRH:Relative insensitivity of loss to irradiation of BeO and high thermal conductivity make it aninteresting potential candidate material (considered a candidate for many years for LH):

Future work planned:

Thermal conductivityfor more ceramics

Irradiation of multilayer mirrors

EU database work

• TW6-IRRCER Database task now underway:

UKAEA: Development of the implementation of the ceramic irradiation database,

(M. Brooks and P. Karditsas + A. Gusarov and E. Hodgson)

Provide reference to the results of the EFDA Ceramic Irradiation Programme by

recording all relevant information

Provide a searchable repository of documents

Provide a searchable database suitable for designer of diagnostics and H&CD

systems to find the available information and facilitate design choices.

• Will use the current EU Fusion Materials Database as framework

• To be extended for full ITER partner use at a later date

• Now discussing how the data should be presented and what information it should contain ==>

George’s table - Irradiation tests: needs for ITER(Comments / input from RF and EU only)

WBS Component to be tested

Critical parameters

Comments

C03 /Thomson scat. X pt.

Plasma facing and ML mirrors

Refectivity change

Dose rate 0.2 Gy/s for ML mirror. Corrosion ?

C03 /Thomson scat. Divertor

Silica, Al2O3 prism reflector, gold reflector

ML mirrors

Laser damage KU-1 windows have been tested, data for sapphire exists

E02/H-alpha ML dielectric mirrors

No fibers in vessel

Heating, reflectivity change

KU-1 windows have been tested

E12/CXRS ML mirrors,

Fibres

Heating, reflectivity, transmission change

KU-1 windows have been tested

ML mirrors are common components - joint effort ?

G07/Langmuir probes

MI cables Thermal path, RIC, RIED, R/TIEMF

George’s table - Irradiation tests: needs for ITER

WBS Component to be tested

Critical parameters

Comments

A01/Outer vessel sensors

Hall probes Behaviour at high T

Electrical contacts/connections

A04/Ext Rogowski

Optical fibre as current sensor

V. coeff stability, transmission, background

Need on-line irradiation test and neutron tests (between 1019 and 1021 n/m2 ; ≤3 MGy)

G06/IR thermography

Sapphire fibre Absorption / RL

Need neutron tests to 1021 n/m2

Systems with transmission fibres

large core (600 µm) Al-coated H2-loaded fibres.

Rad- induced absorption and RL

(~ 1 to 5 10^17 n/cm2)