Core Shroud Replacement
Design, Fabrication, Removal, Installation & Disposal of Core Shrouds
Recent inspections have revealed indications beyond the heat-affected zone of core shroud welds. Irradiation-Assisted Stress Corrosion Cracking (IASCC) affects the base material of the shroud. To help maintain your plant integrity, AREVA’s innovative replacement concept includes bolted forgings that eliminate all vertical and circumferential welds.
The shroud assembly is removed and sectioned for disposal using conventional and EDM processes. AREVA’s replacement concept utilizes bolting rather in-air welding techniques on irradiated materials to reduce dose and allow replacement activities to be done underwater.
The replacement core shroud is manufactured from a forging, eliminating welds and thus reducing future inspections. The bolted subsections are designed with access for future bolt inspections, which will be minimal.
The AREVA process eliminates welds on irradiated materials that could result in future weld indications and significantly reduces dose.
Features & Benefits
- Underwater core shroud replacement reduces dose
- 100% forged components
— Forged cylinders – alleviate vertical welds
— Bolted connections – alleviate horizontal welds
— Type 316L-NG material per BWRVIP-84
- Bolted connection to existing shroud support plate
— No need to drain vessel
— Much lower dose for entire project