At power unit No. 4 of the Beloyarsk NPP with a BN-800 reactor, a "hot" redundancy scheme for the frequency converters of the main circulation pumps of the second circuit has been implemented. According to the station's press service, the modernization allows power to be switched to a working converter in less than 2.5 seconds – faster than the protection systems for deviations in the rotation frequency of the main circulation pumps can activate, which would otherwise threaten a 33% reduction in reactor power from nominal and a downtime of almost 85 hours.
The automation maintains pump speeds, preventing shutdown due to an emergency setpoint. The solution was developed and installed by the personnel of the electrical shop and Uralatomenergoremont. The preparatory cycle – from idea to design documentation and equipment manufacturing – took about five years.
A positive conclusion from Rostekhnadzor has already been received. In the future, similar logic is planned to be applied to the pumps of the first circuit, where the system's reaction will need to be accelerated to an interval of less than one second. BAES specialists consider this task solvable.
For the Sverdlovsk region, where the station provides about 16% of electricity consumption, eliminating many hours of power losses on the fast reactor means a more stable load schedule. On the scale of domestic nuclear energy, this is the first case where a vulnerability in a frequency converter is proactively addressed, preventing automatic reactor unloading.
