https://en.wikipedia.org/wiki/BN-1200_reactor
In early 2012, Rosatom's Science and Technology Council approved the construction of a BN-1200 reactor at the Beloyarsk Nuclear Power Station. Technical design was scheduled for completion by 2013, and manufacture of equipment would start in 2014. Construction would begin in 2015 with first fuel loads in 2017 and full commercial operation as early as 2020.
...
In 2015, after several minor delays, problems at the recently completed BN-800 indicated a redesign of the fuel was needed. Construction of the BN-1200 was put on "indefinite hold", and Rosenergoatom stated that no decision to continue would be made before 2019. In January 2022, Rosatom announced that a pilot BN-1200M would be built by 2035.