well i guess they got the picture wrong..here is the link to the rubins site, they have a pretty beautiful drawings ……

http://www.ckb-rubin.ru/eng/project/submarine/noatompl/index.htm

the sectional dia that seen in that site is this one —- of Project 636

http://www.ckb-rubin.ru/eng/project/submarine/noatompl/img/13a.jpg

and down below there is a pi of Amur too…. but not big like the 636s

http://www.ckb-rubin.ru/eng/project/submarine/noatompl/img/16a.jpg