Development of Codes and Standards for ITER In-Vessel Components

Abstract

This paper describes the changes made to existing version of the Structural Design Criteria for In-vessel Components (SDC-IC) within the ITER project, as a result of the revision and update process carried out recently. Several ITER components, referred to as In-vessel Components, are located inside the ITER Vacuum Vessel: (a) Blanket System: shields the Vessel and Magnets from heat and neutron fluxes; (b) Divertor: extracts heat, helium ash and impurities from the plasma; (c) Fuelling: gas injection system to introduce fuel into the Vacuum Vessel; (d) Ion Cyclotron Heating & Current Drive System: transfers energy to the plasma by electromagnetic radiation; (e) Electron Cyclotron Heating & Current Drive System: uses radio waves to heat to the plasma; (f) Neutral Beam Heating & Current Drive System: accelerates Deuterium particles into the plasma; (g) Lower Hybrid Heating & Current Drive System: drives electric current into the plasma; (h) Diagnostics: measurement systems to control plasma performance, and further understand plasma physics; (i) Test Blankets: demonstrate techniques for ensuring tritium production within the tokamak. ITER In-vessel Components will be subjected to special operating and environmental conditions (neutron radiation, high heat fluxes, electromagnetic forces, etc.). The effects of irradiation on them, including embrittlement, swelling and creep, are not addressed in the existing commercial codes. These conditions are different from conditions in fission reactors and create challenging issues related to the design of these components. For this reason the Structural Design Criteria for ITER In-vessel Components (SDC-IC) [1] was developed for design purposes. SDC-IC was based mainly on the RCC-MR [2] code, and included rules for assessment of effect of neutron irradiation. In 2008 some issues were identified: (1) Some parts had not been fully prepared to cover all needed areas for design; (2) Some important topics needed to be improved; (3) New editions of codes on pressure equipment had been published; (4) No manufacturing rules were included, so consistency between manufacturing rules to be used and design rules in SDC-IC needed to be demonstrated; (5) Compliance with the ESP (French Decree concerning the Pressure Equipment Directive 97/23/EC for non-nuclear pressure vessels) [3] and ESPN (French Order applicable for pressure vessels intended for nuclear facilities) [4] needed to be addressed. The work carried out for Fusion For Energy (European Union’s Joint Undertaking for ITER) is: (a) Modification of design rules, incorporating rules from recently developed codes, and development of specific design rules to cover ITER specific issues and operational conditions; (b) Demonstration of consistency between design rules in SDC-IC and european standards used for manufacturing, in particular EN 13445 [5]; identifying areas where consistency is not provided; (c) Assessment of the compliance with the Essential Safety Requirements of the French Regulations (ESP and ESPN).