New Automatic Radiation Monitoring Network in Slovenia

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1 International Conference Nuclear Energy for New Europe 2006 Portorož, Slovenia, September 18-21, New Automatic Radiation Monitoring Network in Slovenia Michel Cindro, Barbara Vokal Nemec Slovenian Nuclear Safety Administration, Železna cesta 16, SI-1000 Ljubljana, Slovenia ABSTRACT The Slovenian nuclear safety administration gathers all on-line dose rate data measured by the various automatic networks operating throughout the territory of Slovenia. With the help of the PHARE financing program and in close cooperation with the Environmental agency of RS the upgrade of the existing network begun in 2005 and was finished in March The upgrade provided new measuring sites with all relevant data needed in case of a radiological accident. Even bigger improvement was made in the area of data presentation and analysis, which was the main shortcoming of the old system. 1 INTRODUCTION During the last year, the system for monitoring of ionizing radiation in the environment at the Ministry of environment and spatial planning has been renewed. The system continuously monitors the levels of radiation throughout the territory of Slovenia and provides a timely warning or alarm in the case of elevated levels of radioactivity, indicating the arrival of the contaminated plume. The contamination can be either due to a nuclear accident (emergency in a nuclear power plant), a radiological accident (for instance smelting of a radioactive source in an iron smelter) or even a terrorist attack (»dirty bomb«). The Slovenian nuclear safety administration (SNSA) has been gathering all on-line dose rate data measured by the various automatic networks operating throughout the territory of Slovenia since the late 1980-ies. Until the last year data from 42 measuring station were collected [1]. Within the scope of the PHARE financing program, and in close cooperation with the Environmental agency of RS (EARS) the upgrade of the existing network begun in 2005 and was finished in March 2006 [2]. The upgrade was twofold: 35 new measuring sites were added with both radiological and meteorological data available (Figure 1). At the same time the system for data collection and analysis was redesigned to ensure a quick insight into the radiological situation throughout Slovenia and the neighbouring countries by means of automated data exchange.

2 904.2 Figure 1: Measuring sites: 35 new stations of radiation monitoring network are shown in red, 42 old ones in blue. 2 NETWORK DESIGN As the EARS already maintains many sites for both radiological and meteorological measurements, it was decided in the planning phase of the project that the new locations for gamma dose rate probes will be chosen among their existing sites that were not yet equipped with GM probes. In this way, many problems and costs concerning the infrastructure were avoided, which enabled us to install more gamma dose rate probes within the available budget. Even though the sites which were used belong to different networks within ARSO, the intention was to make as many stations as possible uniform with regard to location surroundings, data gathering and transfer to the central unit. A typical site is shown in the Figure 2. It is preferable that the area is flat and covered with grass, as far as possible from any buildings. As a consequence of the arrangement with ARSO, all meteorological and hydrological data from already existing sites are now available in the new system, to complement the radiological measurements. It was also possible to include data from existing aerosol monitors into the new system, as well as dry deposition measurements, Krško NPP process monitors and data from international exchange.

3 904.3 Figure 2: The measuring site at the Maribor airport. The gamma dose rate probes are in the front, various meteorological instruments can also be seen in the background. The new sites were equipped with gamma probes MFM 203 made by the Slovenian company AMES d.o.o. and precipitation gauges MPS System Total Rain Weight Sensor. In addition, 2 autarkic stations were also delivered, equipped for dose rate and precipitation measurements, which can be placed anywhere that they are needed. They are completely independent with solar panel, battery power and wireless communication. They are also equipped with GPS systems and automatically transmit their position to the central unit. The data from all stations within the new network are gathered every 30 minutes at the central point at the EARS. Special attention was given to the reliability of the system, from the stations themselves to the main system servers. Stations are equipped with internal memory for data storage and batteries in case of power failure, so data are stored locally until they can be transferred. The servers for data gathering and analysis, both at the ARSO and SNSA have backups in case of breakdown. 3 DATA GATHERING AND ANALYSIS SOFTWARE Apart from the increase in the number of stations, the biggest improvement is in the area of data analysis and presentation. The tasks of the software are to gather data from the stations, check for quality, assimilate them into the database, archive, produce alarms in case of elevated measurements and provide means for a quick and thorough analysis of the measured data to the operator. Data are currently gathered at both organisations, ARSO and SNSA. Data from the new stations and old ARSO meteorological and radiological sites are gathered and quality checked at the ARSO central, then transferred to SNSA where they are assimilated into the system database along with data from other subsystems that SNSA collects.

4 904.4 The visualisation and analysis software has 3 operating modes. To name the modes: The basic mode is accessed through the public portal and is available at It enables the public to get a quick snapshot at the situation in Slovenia or to interactively survey time diagrams and observe trends or examine geographical presentations of data with layers denoting different measured quantities (Figure 3). It is open for everyone, with real-time data and no delay. Figure 3: Geographical presentation of gathered data. Layers which can be turned on and off denote location names, gamma dose rate, precipitation, wind direction and temperature. The second mode is accessed through the internal portal, which in addition to simple presentations available for the public, offers many analytical tools, conceived mainly for the monitoring personnel at EARS and SNSA. The operators can quickly assess the situation by looking at the snapshot graphical presentation of gamma dose rate and precipitation (Figure 4) or numerical presentation of data in half-hour intervals (Figure 5). All data can be exported either graphically as JPG files or numerically (ASCII, EXCEL).

5 904.5 Figure 4: Simultaneous presentation of gamma dose rate and precipitation is used for quick assessment of probe operation or radiological situation. Figure 5: Numerical presentation of gamma dose rate and precipitation for 30 minutes intervals. Empty slots denote missing data.

6 904.6 One of the more sophisticated tools available to the operators measures the time delay from the time a measurement is made to the moment it is received at the central server. It can point to a faulty or unreliable communication line (Figure 6). Figure 6: The station presented in dark red has less then 30 minutes delays between data measurement and assimilation into the database. The one presented in light blue, however, has frequent communication breakdowns so the data for more intervals are stored on-site and then transmitted at the same time to the central station. The number of collected data is the measure of the reliability of the system, so statistical analysis of the data is crucial. To this end an analytical tool was devised that presents all relevant statistical data for all chosen stations (Figure 7). Even more tools are available at the internal portal, which can be accessed only with a username and password. Figure 7: Statistical analysis provides the information on the number of received data, mean values, sums, maximal and minimal values.

7 904.7 The third mode of system operation is accessed through the administration portal, and enables the administrator to perform all necessary maintenance work. It is possible to add or delete stations and operators, change alarm levels, introduce delays for public presentation and many more necessary functions. The alarming feature is one of the most important tasks of the system. Three levels of alarms are set: warning for one station with gamma dose rate over 250 nsv/h and alarms for simultaneous measurements over 350 or 500 nsv/h respectively on 3 different stations. According to the distribution lists for each level, alarms are transmitted to GSM phones, e- mails and fax machines. In cases indicating potential radiological problems in the environment the data collection process is stepped up to 5 minute intervals. Slovenia has an obligation to send its measured data according to bilateral agreements with its neighbours and to the Joint Research Centre in Ispra. This will now be done through automatic generation of file in any prescribed format, which will then be sent to different computer addresses. In the same way, data received from neighbouring countries are also included in the system and can be viewed and analysed in the same way as Slovenian data. It is also possible to introduce arbitrary values in the system, providing alarms for testing purposes and exercises. This is done on a separate set of data and does not affect the normal work of the system. While generated data are presented, real data received from the stations are normally processed and stored in the database. 4 CONCLUSIONS The renewed and upgraded early warning network in Slovenia provides automatic data collection, control and archiving of data that are essential for a comprehensive survey of the radiological situation in Slovenia. In case of a radiological or nuclear emergency the early warning network will be an indispensable source of relevant information describing the radiation levels throughout the Slovenian territory. The data thus provided will serve as a firm basis for any decision maker concerning eventual protective measures for the population. REFERENCES [1] D. Mitić, M. Križman: Automatic Radiation Monitoring System in Slovenia; IRPA Regional Congress on Radiation Protection in Central Europe, Dubrovnik, Croatia, May 20-25, 2001, p. 66. [2] M. Cindro, D. Mitić, A. Stritar: Designing the Upgrade of the Early Warning System in Slovenia, International Conference, Nuclear Energy for New Europe 2004, Portorož, Slovenia, September 6-9, 2004.