The KLT-40S is a barge-mounted floating SMR producing 35 MWe per module. The design is a compact loop configuration with most primary system components external to the reactor pressure vessel. The length of the hot and cold leg pipes connecting the reactor vessel with the two steam generator vessels is kept very short to reduce the likelihood of a large-break loss-of-coolant accident and because of space constraints on the barge. The design is based substantially on the successfully operated KLT-40 reactors that provide propulsion to a fleet of commercial ice-breakers.

The 1.2 m diameter by 1.2 m tall reactor core consists of 121 hexagonal fuel

assemblies with uranium enrichment of less than 20%. Control rods and burnable poison rods are used to control reactivity. The four external steam generators are a helical coil type. The four primary reactor coolant pumps are also external to the reactor vessel.

The KLT-40S is normally configured with two units on a 30 m wide by 140 m long barge and will be delivered to the operating site fully constructed and ready for operation. Initial customers include the isolated communities along Russia’s Arctic coast. To extend operations in more remote locations, the barge will be dispatched with multiple core loadings and the reactors will be refueled on-board after three to four years. It is expected that the barge will return to a centralized facility every 10-12 years for major overhauls.

The first KLT-40S floating power plant began construction in 2007 and the barge was launched in the Baltiysky Zavod shipyards in June 2010, prior to installation of the reactor units. The first barge, named the Akademik Lomonosov, is expected to be operational at its deployment site in 2016. Key parameters and a representative graphic for the KLT-40S design are given in Figure 2.7. [7]