SFDS radiation monitoring system

All the operations on SFDS radiation monitoring are performed in compliance with the "Radiation monitoring working program" specifying the monitoring kinds, its intervals and success criteria.

At the stage of preparation to spent fuel transporting to SFDS, "Atomspetszashchita" company, based on Zaporizhzhya NPP specification, performs calculations of the radiation parameters depending on the characteristics of particular fuel assemblies planned for loading into the ventilated storage casks, and the safest procedure for arrangement of the ventilated storage casks at SFDS site.

Radiation monitoring can be split into following:

• ‌ Radiation monitoring during loading of spent fuel to VSC at the power unit;
• ‌ VSC transportation;
• ‌ Installation of casks at SFDS storage;
• ‌ Radiation monitoring in the process of spent fuel storage at SFDS.

Radiation monitoring during storage is performed with specified periodicity by portable dosimeters, and constantly – by specially developed and installed "SFDS Information – measuring radiation monitoring system" (SFDS RM IMR).

System purpose

SFDS RM IMR is an automated system of constant informative radiation monitoring.

In compliance with the p.4.5 of "General safety provisions of nuclear power plants" (NP 306.1.2/1.034-2000), SFDS RM IMR belongs to normal operation systems; in part of impact on safety it belongs to safety class 3 (classification identification – 3N).

Basic functions of the SFDS RM IMR

• ‌ Measurement, primary processing of data about radiation monitoring parameters;
• ‌ Comparison of current values of the monitored parameters with the specified limiting values, generation of signals about their exceeding;
• ‌ Generation of signals about exceeding of limiting levels to the sound alarm devices;
• ‌ Control of operation modes of detection facilities in compliance with internal logics of the system functioning;
• ‌ Display of monitored parameters in a format suitable for good perception, diagnostics and control;
• ‌ Submittal to the operator of the SFDS RM IMR control means, using advanced man-machine interface;
• ‌ Maintaining database and information archiving;
• ‌ Information storage and documenting;
• ‌ Generation of data to the stationary APCS system.

System structure and purpose of its components

SFDS RM IMR is a 3-level system with centralized control and distributed structure of data measurement, acquisition and processing.

The lower level of the system is formed by the equipment of automatic measurement of radiation and technological inspection parameters installed at the monitoring points, and the sound alarm device installed in the SFDS monitoring point.

The average level of the system is formed by hardware and software of the data acquisition station located in the SFDS monitoring post room.

The upper system level is formed by hardware and software of the operator’s workstation located in the central control board room – 2.

List of monitoring points with the installed lower level equipment is given in the table below.

Primary power supply of the data acquisition station is done from two feeders 220V of the NPP house load. Reliable power supply is ensured by means of automatic switching facilities of the feeders and uninterrupted power supply system. Analyzers of the grid parameters are also included in the data acquisition stations.

For display of the current information and remote control of the technical equipment, the data acquisition station includes control boards with LCD displays.