Radiation monitoring system for Kudankulam NPP: project development and implementation goes ahead

by Daria Plyshevskaya

Upon results of the tender, PROM Engineering (Russia) was awarded a contract for the manufacture and supply of an automated radiation monitoring system (ARMS) in the framework of constructing two power units of Kudankulam NPP with WWER-1000 reactors in India.

The Kudankulam NPP ARMS has a number of considerable advantages when compared to the existing systems at Russian nuclear plants today due to the great reliability provided by its system structure, the wide range of objectives that it can achieve, the use of state-of-the-art instrumentation with wide measurement ranges, software usability and equipment serviceability.

About ARMS

ARMS is the major system for control of radiation safety at the NPP. It allows damage to one or other of the protective barriers to be identified at an early stage and prevents the penetration of radionuclides into the environment. Information exchange between the Automatic Process Control System and ARMS enables continuous analysis of the NPP to be carried out and failures with the main process equipment to be predicted.

ARMS combines both continuous and periodical monitoring functions:

• monitoring of the radiation process

• monitoring of the radiation status in a power unit and at the site

• monitoring of gaseous and particle releases into the atmosphere

• monitoring of radionuclide releases into the open aquatic environment

• monitoring of the spread of radioactive contamination

• monitoring of collective and individual radiation doses received by personnel

The ARMS system for use at a nuclear plant is a complex system worked out according to an hierarchical approach. It consists of self-contained subsystems for routine operation and for emergency control. For emergency control the subsystems are made with dual redundancy for measuring channels, communication and power supply lines. It must be able to function for all the types of NPP operation, including design basis and beyond design basis accidents, right up to NPP decommissioning.

Monitoring optimization

Work on monitoring the scope for optimization at the Kudankulam ARMS has gone beyond the period of detailed project development. The optimization of the ARMS project focused on the selection of the most informative parameters for monitoring at the NPP, which is equipped with a WWER-1000 (pressurized water reactor) type reactor. This has lead to the complete reconsideration of the whole project bearing in mind the new capabilities of the latest up-to-date equipment (computer facilities and measurement instrumentation) and the latest normative requirements. Furthermore, the main aims were was to consolidate the maximum possible number of radiation control objectives within a single automated system and to assign main monitoring functions to the measuring of channels in permanent automatic mode.