I am wondering about those intakes too, they look too big to be see inlet intakes for the ballast tanks too...... I do see, however, that the image heuhen linked above has just such an intake as well
The picture I posted above is from 50 лет Победы (50 Let Pobedy, 50 Years of Victory). I think those intakes are a part of the cooling system for the reactor, more in the Heat exchange system or the main condenser system.
The reason I believe that, is because that when I saw a documentary about those Russian ice breaker, there was one common thing about them, They can't operate in the water further south (like the Mediterranean sea) due to that if the sea water is to hot, they can't cool down the reactor efficient enough. And if we compare where those vents are placed compared to where the reactor lid are placed...
The setup are similar for an nuclear submarine. Just that An ice breaker have twin reactors that are so much more powerful, and thus need more water for the condenser system.
Just found this one (If ace.. want the size of an Russian icebreaker Nuclear reactor for the bellow deck parts...:
http://img.russianpatents.com/1143/11434640.gif