Assessment of a bolted-flange connection for ITER Test Blanket Module

In ITER, the 'Pipe Forest (PF)' is a network of pipes that connects the Ancillary Equipment Unit to the Test Blanket Module (TBM) at the level of the equatorial port-plug of the reactor prototype. The goal of ITER's TBM program is to validate concepts to be adopted for the DEMO tritium Breeding Blankets. Different types of pipes are mounted on the port-plug among which those used for cooling or tritium processing. During plasma operation, the PF has to accommodate severe thermomechanical loads. It shall also provide protection from abnormal contamination and be designed to ease connection/disconnection operations. With numerical simulation, this work assesses the use of bolted flanges as an alternative to the welded solution to connect the PF on the TBMs inside the port cell environment. The proposed designs integrate metallic seals as well as an embedded cooling system in the flanges when necessary, to limit the temperature of the seals and the bolts and prevent irreversible damage. It is shown that bolted-flange junctions for the PF are a credible solution. Still, important stresses in the socket of the flanges are present but do not represent a problematic issue for dimensioning purposes, as they shall be accommodated with a small amount of plastic strain.

Automated summary

The TBM program in ITER aims to validate concepts for the DEMO tritium Breeding Blankets, requiring the PF pipe forest to withstand severe thermomechanical loads during plasma operation while providing protection and ease of operation. This study assesses the use of bolted flanges as an alternative to welded solutions for connecting the PF on the TBMs inside the port cell environment, showing that bolted-flange junctions are a credible solution despite the presence of important stresses in the flange socket.