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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