A French consortium made up of nuclear reactor vendor Areva, utility EDF, research association CEA and shipbuilder DCNS has launched a two-year feasibility study of a submerged nuclear power plant, called Flexblue.
The plant, including a reactor with an output of 50MWe-250MWe and its turbogenerator and power plant, would be installed in a 100m long, 12m-15m diameter submarine-type hull and then anchored to the sea bed (perhaps to a depth of 60-100m), several kilometres or a mile or so offshore, according to a DCNS report.
The reactor would take in seawater for cooling; seawater would also act as an emergency coolant. Transmission lines would carry electricity generated back to land.
Although the project could use Areva's current research into a 100MWe reactor, it could also be adapted to other small-to-medium reactors, according to DCNS.
The feasibility study will examine technical options and industrial design, potential markets, competitive advantage, proliferation resistance, underwater installation issues demonstrating a Generation 3-level of safety.
Like other small reactors, the entire unit could be assembled, tested and sealed in the controlled conditions of a factory. It would be transported to its final location on a semi-submersible barge, and sink, controlled by ballast, to the sea bed. Flexblue would be unmanned and operated by remote control, except for critical times like start-up and maintenance, when technicians would reach it by mini-submersible. It would be protected by a steel mesh tent.