Start-up of Beloyarsk NPP Unit 4 is critical for development of fast neutron nuclear reactor technology.

The heart of the power unit is BN-800 reactor, which is the most powerful fast neutron reactor capable of operation with MOX fuel (mixed plutonium and uranium oxide fuel).

BN-800 and other "fast reactors" represent a new technology for transition to a closed nuclear fuel cycle in nuclear power industry. This will improve the efficiency of fuel use at NPPs, solve the problem of nuclear waste and provide the world with a reliable and sustainable source of clean energy.

I&C designed for Beloyarsk NPP Unit 4 is much the same as instrumentation & control systems for VVER reactors.

The main differences relate to the fact that liquid sodium is used as a coolant in fast-neutron reactors. High boiling point of 883 degrees Celsius in normal conditions ensures inherent safety of the reactor plant and allows operators to focus on monitoring of appropriate operational parameters of the coolant.

For this reason, special tools for measurement and monitoring of sodium systems were developed together with sodium electric heating instrumentation and control system. In particular, the number of monitored heating areas was increased up to 3500, and temperature sensors (two thermocouples) were installed in each area in order to maintain coolant temperature within the range of 550 +/-30 oC.

For the purpose of sodium parameters monitoring, new "sodium" sensors were developed and introduced. They measure pressure, level and flow rate, monitor sodium leakage and measure hydrogen concentration in reference points where conditions for containment depressurization may occur.

Changes were also introduced to I&C subsystems aimed at controlling the turbine hall parameters, due to the use of steam condensing turbine K-800-130/3000.

In addition, I&C of Beloyarsk NPP Unit 4 allows to perform online self-diagnostics and process equipment monitoring, thus providing the operator with the full scope of necessary information.

At the end of 2015, the 4th power unit of Beloyarsk NPP with BN-800 reactor started to supply power in the unified power grid of the Urals and Russia. Currently power generation is approaching 100% of the design basis.