Specialists began to modernize the containment monitoring system (CMS) of the reactor compartment in the course of the planned overhaul at the third power unit of the Kalinin NPP. This is the first time such work is being carried out at Russian nuclear power plants.

According to Chief Engineer of the Kalinin NPP Aleksandr Dorofeyev, the containment shell is designed to protect the reactor plant from external natural and man-made influences, while also preventing the release of radioactive substances into the environment in the event of an emergency. The containment consists of one-meter-thick cylindrical reinforced concrete wall and a dome, which ensure the tightness of the internal volume. The strength of the structure is provided by high-strength reinforced ropes located in special channels inside the wall. They are tensioned with jacks, squeezing the shell, which prevents the cracking of the concrete.

“Prior to this, the ropes reinforcement, containment state and its tightness were enabled by three separate systems. Through this modernization we’ll replace them with a single system that will contribute significantly to the safety of the NPU,” A. Dorofeyev said. “We are currently replacing the workstations, basic and applied software, information exchange controllers, commutators and signal processing devices.”

In addition, an expert system based on the domestic software complex "CONT" will be introduced into the CMS. It will be used to analyze the state of the containment and assess its strength. To cover the entire volume of the containment, the system virtually divides it into 15,000 controlled zones, creates a detailed three-dimensional model and makes calculations for each zone.

Implementing the expert system will allow to assess how operation-ready the containment is to meet the demands of day-to-day utilization of the NPU. The data gathered will help to optimize the maintenance works regarding the adjustment of ropes reinforcement.

Realization of such a large-scale project will significantly simplify system maintenance, reduce the time of personnel training, as well as lower the probability of abnormal operation of the NPU that is caused by human error.