Patent ID: 11935665
Assignee: ELECTRICITE DE FRANCE
Field: Chemical engineering (Chemistry)
Classification: CPC G  B | IPC B  G

Claim 21:
22. A facility for treating aqueous effluents from a primary circuit of a nuclear power plant, wherein the aqueous effluents comprise boric acid, the facility comprising:
a multi-stage assembly composed of multiple reverse osmosis modules, a general inlet, at least two general outlets, and multiple recycling lines,
wherein each of the multiple reverse osmosis modules comprises an inlet, an outlet, and a reverse osmosis membrane configured to let through a permeate which is less concentrated in the boric acid than an incoming liquid in the reverse osmosis membrane and to retain a retentate which is more concentrated in the boric acid than the incoming liquid, and wherein the multiple reverse osmosis modules are arranged in parallel and in series so as to define a one-way fluidic circuit from the general inlet to the at least two general outlets, and
wherein each of the multiple recycling lines fluidically connects the outlet of a first reverse osmosis module of the multiple reverse osmosis modules with:
the general inlet,
one of the at least two general outlets when the one-way fluidic circuit does not directly connect the outlet of the first reverse osmosis module to the one of the at least two general outlets, or
the inlet of a second reverse osmosis module of the multiple reverse osmosis modules when the one-way fluidic circuit does not directly connect the outlet of the first reverse osmosis module to the inlet of the second reverse osmosis module,

wherein the multi-stage assembly comprises a boric acid enrichment zone and a boric acid depletion zone, each of the boric acid enrichment zone and the boric acid depletion zone comprises one or more of the multiple reverse osmosis modules, and one or more stages in series, wherein each of the one or more stages consist of the one or more of the multiple reverse osmosis modules arranged in parallel, and
wherein the facility further comprises boric acid concentration sensors at selected points of the multi-stage assembly and the multiple recycling lines being configured to, based on results provided by the boric acid concentration sensors:
introduce a fraction of the boric acid fluid into an incoming fluid of the second reverse osmosis module through one of the multiple recycling lines,
introduce a fraction of the purified fluid into the incoming fluid of the second reverse osmosis module through one of the multiple recycling lines,
introduce into the boric acid fluid the retentate of the first reverse osmosis module through one of the multiple recycling lines, when the first reverse osmosis module is located in the boric acid enrichment zone, or
introduce into the purified fluid the permeate of the first reverse osmosis modules through one of the multiple recycling lines, when the first reverse osmosis module is located in the boric acid depletion zone.