Analysis of Residual Ion Dump (RID) of Diagnostic Neutral Beam (DNB) injector for ITER

Residual Ion Dump (RID) of the 100 kV negative hydrogen ion source based Diagnostic Neutral Beam (DNB) injector, utilizes electrostatic fields for the ion beam deflection. There are four channels formed by five panels of length 1000 mm. Each panel consists of 10 actively cooled elements called Tube Elements (TEs) made up of CuCrZr alloy. All TEs are of 1.5 m length with cross-section of 20 mm × 100 mm with a central bore of 16 mm provided for the coolant passage. Water with an inlet temperature of 55 C is used as coolant. Total flow rate and inlet pressure provided for RID are 5 kg/s and 2 MPa respectively. RID is designed for two types of cycles viz; 8.6 × 10⁵ pulse trains of 3s ON/20s OFF and 1.29 × 10⁷ modulations of 100 ms ON/100 ms OFF. Beam transmission code (BTR) developed by Russian Domestic Agency, was used to determine the power density profiles on the heat facing surfaces of the TEs. Beam divergence of 3 mrad was considered and heat fluxes as high as 0.95 MW/m² are incident on the RID and total average power on RID is ~2.5 MW. Most heated TE with Design Description Document (DDD) design was taken for analysis. Thermal hydraulics calculations are carried out on spread sheets where as thermal and thermo- structural analyses were carried out using Finite Element Analysis using ANSYS 11. Heat transfer coefficients as a function of both local bulk temperature and inner wall temperature are used. In the post processing of structural results, both Monotonic and Cyclic types of damage verifications were carried out with ITER code Structural Design Criteria for In-vessel Components (SDC-IC). In this paper, we present ANSYS analyses results and damage verification results of SDC-IC which eventually culminate in the finalisation of the design phase.