Transcript Slide 1

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:
Calculation of radiation fields
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.
Some of the required diagnostic
system will be exposed to intense
radiation
fields (up to 100 Gy/s) and also
to lithium ions bombardment.
Radiation effects may make the
diagnostic to fail.
This code is able to simulate the
generation of neutrons, gamma
rays and other d-Li reaction
products.
Target &
Back-Wall
Deuteron
Beams
Footprint 200 x 50 mm
Test
Modules
Silica material was chosen for the
calculation because most of the
diagnostics are based in optical
measurements.
Case-B
Case-A
17.5 m
Control system
Contact probe for Thickness Monitor
Beam
Target
Retractable Mirror
Based on electrical conductivity, the monitor has four pins to
measure the amplitude of surface waves on the Li flow.
Plane view of the IFMIF building showing the
locations of FM laser radar
Probe head of the Thickness Monitor.
Wave pattern
-50
1.0E0
-100
-150
-200
3.0E-1
5.0E0
3.0E0
3.0E-2
1.0E0
0
50
100
150
200
The Interferometer technique is
proposed for this monitoring.
Critical elements will be optical
components as the window and the
mirror.
•MgO insulators: it may be short circuited due to the Li ions
bombardment.
Measurement of the deuterium footprint and Li
free surface temperature is necessary for the
safe operation of IFMIF.
•Stepping motor: there is a risk of malfunctioning due to the
swelling in its central gear that will be exposed to high
neutronic fields.
IR camera
Electrical
conductivity
contact probe
Stereoscopic
Optical System
Back-plate &
Nozzle status
2.0E1 1.0E1
Diagnostic system for target temperature
Parameter to be
Proposed
measured
Diagnostic System
Li temperature
3.0E-2
• The metallic probe due to the swelling
•Stepping motor: its electrical coils insulators (usually organic
materials) will be exposed to intense radiation fields)
7 cm
0
The distortion of back plate must be
monitored during Li dumps to check
the required replacement.
FM laser head
Critical elements will be
Modules
50
1.0E-3
1.0E-2
3.0E-2
1.0E-1
3.0E-1
1.0E0
3.0E0
5.0E0
1.0E1
2.0E1
1.1E2
3.4E2
4.0E3
Back plate surface roughness
monitor
21.5 m
Accuracy of this system should be 0.01 mm
1.0E-2
1.0E-1
X (horizontal direction), cm
This work describes the potential radiation effects in the critical
components of the proposed diagnostic systems.
Amplitude of the surface waves should be less than 1 mm.
[Gy/s]
100
The three dimensional model used
in the calculations includes the
latest modifications of IFMIF
design and Test Cell geometry.
Lithium Nozzle
150
m
a
e
b
d-
An average heat load of 1 GW/m2 will be deposited in the target
(20x5 cm2, 5 mm thick).
The Montecarlo code McDelicious
was used to calculate the radiation
fields in the target volume.
200
Z (d-beam direction), cm
The liquid lithium target will be the intersection of the three main
systems of IFMIF.
Energy Deposition in SiO2
Interferometer
Technique
An infrared camera system is the reference
diagnostic for this measurement.
Concerning elements are the optical
components as fibers, lens and mirror.
Critical Components
Relevant
Radiation fields
Potential radiation effects
Lens
20-50 Gy/s
Changes in refraction index
Optical Fibres
-4
5x10 -5
Gy/s
Radioluminescence
Mirrors
4x108 n/cm2/s + Li
Surface Degradation
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
7-8 Gy/s
Radioluminescence &
Optical Absorption
CCD-Cameras & Windows
Optical Windows
108-109
n/cm2/s
Radioluminescence &
Optical Absorption