The "roue" is the set of turbine blades on a given "wheel", hub, or runner. IOW, the steam driving the turbine is forced into the turbine and turns the first stage of that turbine. Its pressure is reduced in so doing, but there is enough residual pressure to turn a second stage, and so on. Don't know how many stages your turbine might have. You get the same terminology in jet engines, where a multi-stage rotary compressor first compresses air, thereby increasing the amount of oxygen (remember, we are flying at high altitudes with little air) discharged into the combustion chamber where it is mixed with aviation fuel and ignited, and the resulting even higher pressure drives turbines on the same shaft as the compressor.

While the AFNOR/Framatome nukular dickshinary gives a long series of types of "roue" as impellers (pumps), wheels or rows (turbines), it gives "roues multiples (à)" as "multi-stage".

Dresden Nuclear Power Station ... investigation revealed that the high-pressure turbine first stage pressure had risen ...
nrcoe.inel.gov/results/ index.cfm?fuseaction=LERSearch.showLerX&lerNum=2372001005

actual plant responded as expected to the high turbine first stage pressure and all ... a telephone conference call on September 27, 2001, Exelon Nuclear failed to ...
www.nrc.gov/NRR/OVERSIGHT/ASSESS/2003q2/dres2_pim.pdf

program for overseeing the safe operation of commercial nuclear power reactors ... the operators to maintain Unit 2 turbine first stage pressure within procedural ...
www.nrc.gov/NRR/OVERSIGHT/ ASSESS/REPORTS/dres_2001020.pdf