Parameter to be measured

Proposed Diagnostic

SystemCritical Components Relevant

Radiation fields Potential radiation effects

Li temperature IR camera

Lens 20-50 Gy/s Changes in refraction index

Optical Fibres 5x10-4-5 Gy/s Radioluminescence

Mirrors 4x108 n/cm2/s + Li Surface Degradation

Wave pattern

Electrical conductivity

contact probe

Contact Metallic Probes High neutron flux Swelling

Insulators Li bombardment Surface short circuit due to Li

Stepping motor High Gamma & Neutrons rad. fields

Degradation of coils insulation and Swelling in the central gear

Stereoscopic Optical System CCD-Cameras & Windows 7-8 Gy/s Radioluminescence &

Optical Absorption

Back-plate & Nozzle status

Interferometer Technique Optical Windows 108-109 n/cm2/s Radioluminescence &

Optical Absorption

7 cm

Probe head of the Thickness Monitor.

Contact probe for Thickness Monitor

Amplitude of the surface waves should be less than 1 mm.

Based on electrical conductivity, the monitor has four pins to measure the amplitude of surface waves on the Li flow.

Accuracy of this system should be 0.01 mm

Back plate surface roughness monitorThe distortion of back plate must be monitored during Li dumps to check the required replacement.

The Interferometer technique is proposed for this monitoring.

Critical elements will be optical components as the window and the mirror.

FM laser head

Target

Control system

Case-ACase-B

Retractable MirrorBeam

21.5 m

17.5 m

Plane view of the IFMIF building showing the locations of FM laser radar

Measurement of the deuterium footprint and Li free surface temperature is necessary for the safe operation of IFMIF.

An infrared camera system is the reference diagnostic for this measurement.

Concerning elements are the optical components as fibers, lens and mirror.

Diagnostic system for target temperature

Radiation Effects in IFMIF Lithium Target Diagnostic Systems

J.Molla*, R.Vila, A.Ibarra: Laboratorio Nacional de Fusión, CIEMAT, Madrid, Spain(*) at present: IFMIF-EVEDA Project Team, Rokkasho-mura, Japan

M.Ciotti: ENEA CR Frascati, Roma, Italy

S.Simakov: Forschungszentrum Karlsruhe, Instituts für Reaktorsicherheit , Karlsruhe, Germany

T. Shikama: Tohoku University, Oarai, Japan

H.Horiike: Osaka University, Osaka, Japan

Introduction:The liquid lithium target will be the intersection of the three main systems of IFMIF.

An average heat load of 1 GW/m2 will be deposited in the target (20x5 cm2, 5 mm thick).

Parameters as lithium temperature (250 C), wave pattern or lithium velocity (15 m/s) must be measured not only for the adequate operation but also for safety.

Calculation of radiation fields

Lithium Nozzle

Deuteron Beams

Test Modules

Footprint 200 x 50 mm

Target & Back-Wall

Some of the required diagnostic system will be exposed to intense radiationfields (up to 100 Gy/s) and also to lithium ions bombardment.Radiation effects may make the diagnostic to fail.

Critical elements will be • The metallic probe due to the swelling

•MgO insulators: it may be short circuited due to the Li ions bombardment.

•Stepping motor: its electrical coils insulators (usually organic materials) will be exposed to intense radiation fields)

•Stepping motor: there is a risk of malfunctioning due to the swelling in its central gear that will be exposed to high neutronic fields.

This work describes the potential radiation effects in the critical components of the proposed diagnostic systems.

The Montecarlo code McDelicious was used to calculate the radiation fields in the target volume.

This code is able to simulate the generation of neutrons, gamma rays and other d-Li reaction products.

The three dimensional model used in the calculations includes the latest modifications of IFMIF design and Test Cell geometry.

Silica material was chosen for the calculation because most of the diagnostics are based in optical measurements.

1.0E0

1.0E0

3.0E0

3.0E-1

5.0E0

1.0E-1

1.0E13.0E-2

2.0E1

1.0E-2

3.0E-2

0 50 100 150 200-200

-150

-100

-50

0

50

100

150

200

Modules

d-be

am

[Gy/s]

Energy Deposition in SiO2

X (horizontal direction), cm

Z (

d-b

eam

dire

ctio

n), c

m

1.0E-31.0E-23.0E-21.0E-13.0E-11.0E03.0E05.0E01.0E12.0E11.1E23.4E24.0E3