Solution for primary circuit of NPP

More than 47 years of experience in supplying control and monitoring systems for both large and small nuclear reactors, as well as related nuclear technologies, including services. We are an established player in the field of nuclear technology control system deliveries, both domestically and internationally.

We meet the legislative requirements of nuclear safety authorities in the Czech Republic and six other countries worldwide.

Reactor Rod Control System

We offer the delivery of a new or modernized Reactor Rod Control System (RRCS). The system complies with current legislative requirements in terms of nuclear safety, operational reliability, user comfort, and maintenance. At the same time, it meets strict qualification standards.

The new, modernized RRCS is essential for ensuring nuclear safety in new or upgraded nuclear units. It is designed on the SandRA platform using the modern digital control and information system ZAT SandRA Z100 and the ZAT Horus HMI system, and it performs functions in categories B and C according to ČSN EN 61226. The system is communicatively linked to the Unit Control and Information System (UCIS).

Key features and benefits include more precise evaluation of rod position for rotary drives (higher accuracy for stepper drives depends on the position sensor used). It also includes test modes for reactor startup procedures and supports reduced system maintenance time during planned outages. The projected lifespan of up to thirty years, supported by the SandRA control system lifecycle, includes extensive diagnostics of the mechanical condition of the drive, rod cluster, and fuel assembly.

The final stage is supplied according to the type of control mechanism, either for linear stepper drives of types LKP-M, LKP-M/3 up to LKP-M/4, ШЭМ-3, or for synchronous rotary drives of types RD42, РД42-4Р.

The system provides power supply and position evaluation from sensors of types UP-1 to UP-3, UP-4, ДПШ for linear stepper drives, and from sensors of types LD-1, ИДП for synchronous rotary drives.

The Reactor Rod Control System, supplied by ZAT a.s., currently ensures reliable and safe nuclear fission in VVER440/1000/1200-type reactors. At the same time, we are ready to adapt the system based on requirements for other types of control mechanisms and for other types of large and small reactors.

Reactor Control System

The Reactor Control System (RCS) is designed for the automatic regulation of the reactor's neutron power and steam pressure in the main steam header. The system is implemented on the SandRA Z100 platform.

We offer the delivery of both new and modernized pressurized water reactor power control systems, meeting current legislative requirements in terms of nuclear safety, operational reliability, and operator comfort. The new power control system is based on the modern digital control system ZAT SandRA Z100 and performs functions in category B according to ČSN EN 61226. It is communicatively linked to the Unit Control and Information System (UCIS).

The system regulates reactor power according to the turbogenerator output and stabilizes the set level of neutron power. It supports both base-load operation and load-following without requiring reactor shutdown or pressure relief.

The functional capabilities of the system, which operates continuously during normal conditions, are constantly monitored through the measurement of relevant parameters.

Exceeding preset parameter limits is signaled. An automated operational diagnostics system is used to monitor equipment status during operation. Data collection and transfer to the company network for archiving and further evaluation are carried out using modern computer technologies.

The Reactor Control System supplied by ZAT a.s. currently ensures reliable and safe power regulation for VVER440-type reactors. At the same time, we are ready to adapt the system for other power levels and types of both large and small reactors based on customer requirements.

Regulation Trip Breaker

The purpose of the Regulation Trip Breaker (RTB) is the rapid disconnection of the power supply intended for the reactor control mechanisms.

The RTB system is divided into two identical sets connected in series to ensure higher reliability. These sets are located in separate rooms and cannot be taken out of service simultaneously.

If either of the RTB sets is activated, it safely disconnects the power supply to the control mechanisms, resulting in a rapid reactor shutdown.

The system operates based on commands from the associated protection systems and commands from the operator in the unit and emergency control rooms. Built-in user functions allow easy testing of the power switches’ on/off operations and collection of diagnostic data. Information about the status of main functions, fault detection, and signaling of faults within the RTB system is also displayed.

It is communicatively connected to the Unit Control and Information System (UCIS).

It performs the highest safety function, category A, according to ČSN EN 61226 and is developed using ZAT-RA technical equipment.

The Regulation Trip Breaker (RTB) system, supplied by ZAT a.s., currently ensures reliable and safe power regulation for VVER440-type reactors. At the same time, we are ready to adapt the system for other power levels and reactor types based on customer requirements.

Reactor Vessel Level Instrumentation System

The system is designed to measure the water level in the reactor vessel, monitoring the level inside the reactor using level measurement assemblies that meet all specified safety design measures and requirements for geometry and construction. The level measurement system uses KNI-LM assemblies designed by ŠKODA JS a.s. These assemblies are based on the neutron measurement method KNI, which has been used inside reactors to date. The measured level is transmitted to the Post-Accident Monitoring System (PAMS).

Redundant level measurement assemblies are used, employing both heated and unheated thermocouples as sensors. These thermocouples maintain good thermal contact with the inner surface of the common tube. The unheated thermocouples serve as reference sensors, making the system independent of the medium temperature.

The system performs safety functions in category B according to ČSN EN 61226 and is implemented on the SandRA platform with Z100 technical equipment. It is communicatively linked to the Unit Control and Information System (UCIS).

The Reactor Vessel Level Instrumentation System, supplied by ZAT a.s., currently ensures water level measurement in the reactor vessel and monitors the water level in VVER440-type reactors; however, we are ready to adapt the system based on requirements for other power levels and types of large and small reactors.

In-Core Measurement System

The system is designed for automatic centralized data collection and processing according to fixed algorithms. It processes real-time basic information about the status of the reactor core, primary circuit, and important parameters of the secondary circuit.

The IN-CORE system includes functions for collecting data from technological sensors (in-core neutron flux sensors, temperature sensors), data collection from other I\&C systems, input data processing (linearization, correction), performing calculations, data preparation and transfer to the supervisory system, and presentation on operator workstation screens. It performs safety functions in category C according to ČSN EN 61226 and is implemented on the SandRA platform using Z200 technical equipment. It is communicatively linked to the Unit Control and Information System (UCIS).

In addition to standard input signal diagnostics, the system also performs insulation diagnostics of sensors (conducted once a year during the fuel outage) and sensor vibration diagnostics. The in-core measurement system, supplied by ZAT a.s., currently ensures reliable and safe processing of information about the status of the reactor core, primary and secondary circuits of VVER440-type reactors, but we are ready to adapt the system based on requirements for other power levels and types of both large and small reactors.

Primary Circuit Technology Control

We offer the supply of a new or modernized system for controlling the primary circuit technologies of a nuclear unit (I\&C NO). The system complies with current legislative requirements regarding nuclear safety, operational reliability, operator and maintenance comfort, and meets strict qualification standards.

It provides control and information functions, enabling the collection of all operational and diagnostic data from connected measurement loops, actuators, and other devices. The system is implemented on the SandRA platform using Z100 and Z200 technical equipment. It performs safety functions in categories A, B, and C according to ČSN EN 61226. It is communicatively linked to the Unit Control and Information System (UCIS).

The system processes and verifies data, enabling online diagnostics and periodic functional testing of equipment.

Post-Accident Monitoring System

This system is a specialized, high-quality, and reliable display system designed to process and present parameters critical to the safety of the power plant, which operators need to use during accident conditions.

Primary functions include displaying parameters essential for post-accident monitoring. Specifically, it monitors critical safety functions of the plant as well as the integrity/breach of barriers against the release of fission products, confirms the functionality of safety systems, and enables operators in the control room to make all necessary safety-related decisions. It also confirms the safe shutdown of the reactor.

Secondary functions include providing information to determine the cause of the accident and supplying data to instruct other personnel to undertake specific and appropriate actions to ensure plant safety. The system performs safety functions in categories B and C according to ČSN EN 61226 and is implemented on the SandRA platform with Z100 technical equipment.

The Post-Accident Monitoring System (PAMS), supplied by ZAT a.s., ensures the processing and display of power plant parameters important for safety in VVER440-type reactors; however, we are prepared to adapt the system based on requirements for other power levels and types of large and small reactors.