In-Core Real-Time Mechanical Testing of Structural Materials (INCREASE) - FIDES-II Joint ExpErimental Programme (JEEP)

Objective: Design a reactor-agnostic capsule capable of housing a variety of in-core mechanical testing instrumentation allowing enhanced experiments for the material science community. Generate high-priority, stress relaxation data for stainless-steel-based materials.

Facilities: Advanced Test Reactor (USA) 

Core Group: INL, NRC, EPRI (USA), CEA (France), NRG (Netherlands), JRC (European Commission), and CVR (Czech Republic)

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INCREASE is aimed at developing the capability to perform a variety of in-core mechanical testing measurements. The initial scope of work includes detailed design and fabrication of a universal irradiation capsule; design and fabrication of a linear variable differential transformer (LVDT)-based sensor to measure stress relaxation; out-of-core verification testing; design and analysis of a complete irradiation test in the Advanced Test Reactor (ATR); assembly and fabrication of ATR stress relaxation experiment; ATR irradiation of selected structural materials; and delivery of in-core real-time stress relaxation data for stainless steels in predominant use in the current light-water reactor (LWR) fleet.

The foundation of this JEEP is the universal capsule design and the irradiation experiment analysis. The primary expense in any reactor irradiation experiment is due to design and analysis, including detailed neutronics, thermal-hydraulic, and structural analyses to meet the safety basis requirements for the reactor. Unlike a typical reactor experiment, in which design and analysis are limited to a single specific experiment, INCREASE will realise a universal design and analysis process that encompases all future experiments using the universal capsule. Future experiments can utilise the prior design and analysis, independent of the structural material and even the mechanical testing apparatuses employed. 


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Image: Schematic of the stress relaxation test rig for Advanced Test Reactor, Idaho National Laboratory

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