Papers by Charles Spencer Pitcher
Fusion Engineering and Design, 2015
Abstract The Diagnostic Port Plugs provide an infrastructure for integrating the diagnostics nece... more Abstract The Diagnostic Port Plugs provide an infrastructure for integrating the diagnostics necessary to operate the machine, while withstanding the nuclear and mechanical loads. They have to provide neutron shielding in order to ensure accessibility to the Port Interspace (PI) region for maintenance operations. This report is about the study to mitigate the ITER Shutdown Dose Rate in Port Interspace. This is a strong design driver for the Equatorial Port Plugs (EPPs) requiring a neutron attenuation of 7 orders of magnitude while maintaining the weight limit. To achieve this challenging task, the design has evolved to an improved double labyrinth configuration with welded shims at the back of the EPP to reduce the gap with the Vacuum Vessel Port Extension. This proved to be very successful for this task. Neutron stoppers have been placed after the gaps necessary for the insertion of the Diagnostic Shielding Modules (DSMs) housed inside the EPP. Effort was also placed in the further development of the DSMs. The latest design relies on a stainless steel structure and lightweight efficient neutron absorbing materials inside. Studies of cross talk with lower ports and the influence of the streaming through the blanket area are presented to give the status of the radiation environment in the Port Interspace region and their contribution to the Shutdown Dose Rate (SDR).
Progress in Nuclear Science and Technology, 2014
This paper concerns the ITER project demands to provide the machine reliability and the human saf... more This paper concerns the ITER project demands to provide the machine reliability and the human safety along and after the ITER operation for making the personnel access inside the ITER bioshield possible. New results are presented for radiation streaming inside the gaps of Diagnostic Equatorial Port Plug (EPP) of ITER with estimation of cross-leakage from over ITER components and consequence of such leakage to upper port with embedded Electron Cyclotron Heating Upper Launcher (ECHUL). It was shown that neutron and photon streaming dominates the radiation environment in the interspace areas at the rear-sides of the ports where personnel access is planning. Several methods to mitigate that adverse radiation streaming are elaborated, with a well considered parametric analysis to reduce gap streaming in EPP by means of different labyrinth configurations, and rails inside the EPP gaps. State-of-the-art codes were applied in the analysis: radiation transport with MCNP5, activation inventory calculations with FISPACT-2007, and interface code R2Smesh to couple transport with activation by using common mesh-tally to produce shutdown dose rate maps with high resolution and fidelity. The mitigation of neutron streaming inside the ports is achieved by understanding of the neutron/photon pathways in radiation transport phenomenon, revealing the dominant radioisotopes, and foundation a strategy for radiation shielding optimization for the ITER ports.
Fusion Engineering and Design, 2014
h i g h l i g h t s • ShutDown Dose Rate (SDDR) analysis for ITER Diagnostic Equatorial and Upper... more h i g h l i g h t s • ShutDown Dose Rate (SDDR) analysis for ITER Diagnostic Equatorial and Upper Port Plugs (EPP and UPP). • ALARA principle and minimization of SDDR are used for the optimization of the port plugs shielding. • Activation and radiation shielding analyses with the MCNP5, FISPACT-2007, D1S and R2Smesh codes. • Significance of contribution of ELM/in-vessel coils and blanket manifolds into the port SDDR is shown. • Shielding improvements for EPP, UPP, and adjacent ITER components were proposed.
Uploads
Papers by Charles Spencer Pitcher