Preliminary Neutronics Analysis of ITER Tip Diagnostic Corner Cube Retroreflectors
Authors: K.R. Tresemer, R. Wood, R. Feder, L. Konkel
Jr., J. Klabacha
Abstract: ITER is an international project under
construction in France that will demonstrate nuclear fusion at a
power plant-relevant scale. The Toroidal Interferometer and
Polarimeter (TIP) Diagnostic will be used to measure the plasma
electron line density along 5 laser-beam chords. This
line-averaged density measurement will be input to the ITER
feedback-control system. The TIP is considered the primary
diagnostic for these measurements, which are needed for basic ITER
machine control. Therefore, system reliability and accuracy
is a critical element in TIP's design. There are two major
challenges to the reliability of the TIP system. First is
the survivability and performance of in-vessel optics and second
is maintaining optical alignment over long optical paths and large
vessel movements. Both of these issues greatly depend on
minimizing the overall distortion due to neutron & gamma
heating of the Corner Cube Retroreflectors (CCRs). These are
small optical mirrors embedded in five locations in the vacuum
vessel wall, corresponding to certain plasma tangency radii.
During the development of the design and location of these CCRs,
several iterations of neutronics analyses were performed to
determine and minimize the total distortion due to nuclear heating
of the CCRs.
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Presented at: TOFE 2014, Anaheim, CA, November
9-13th, 2014
Submitted to: Fusion Science and Technology
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