Research and Ensuring the Stability of Autonomous Auxiliary Power Supply Systems of Nuclear Power Plants

Abstract

This paper describes power supply systems solutions for an ongoing nuclear power plant design. It complies with five defense-in-depth levels, each providing technical measures for assigned safety objectives. They envisage different emergency situations and response actions to transfer the plant to a normal operation or controlled state. The main measure is the functional separation of power supply systems which perform the intended similar functions at different defense levels. Therefore, systems cannot fail simultaneously due to structure or element failure, which is common. The electrical power supply system provides two connections from the off-site grid to redundant sections of the on-site power distribution system, multiple internal power supply sources (AC and DC, backup and alternative power sources). The redundancy principles allow operation in case of an element failure. Each power supply system is prescribed for task categories, according to intended safety functions. All the implemented technical measures improve the plant operation stability and ensure the safety process.