The New Dose Rate Monitoring Network in Finland

Transcription

1 The New Dose Rate Monitoring Network in Finland Radiation and Nuclear Safety Authority Environmental surveillance and preparedness Head of Laboratory Kaj Vesterbacka September 20, 2007 RADIATION AND NUCLEAR SAFETY AUTHORITY

2 1. Introduction 2. The monitoring station 3. Communication 4. Experiences 2

3 Radiation monitoring RADIATION MONITORING OF THE ENVIROMENT EMERGENCY PREPAREDNESS SONNI ULJAS/USVA 0,03 µsv/h-10 Sv/h 3

4 Dose rate monitoring Continuous or periodic monitoring of the environment, either direct or indirect. The main goal to be always aware of the current radiation situation. Dose rate monitoring is needed for decision making support. One of the elements government resolution securing the functions vital to society. 4

5 Legislation Obligation to monitor radiation given to STUK. Domestic legislation and EURATOM agreement (articles 35 and 36). Results are reported to the Member States of the European Commission and Baltic Sea (EURATOM agreement and CBSS: Council of Baltic Sea States, 2001). 5

6 Dose rate monitoring - VAHTI network Built after the Chernobyl accident. The technology is originally from the 80s, communication made over public telephone lines. Low security. The technology is closed and coming to its end. Maintenance is difficult and expensive renewal needed. 6

7 ULJAS network The project of renewing the VAHTI network was started on Jan 1, Funding of the renewal comes from the National Emergency Supply Agency. The project ends Dec 31, 2007, when all stations have been renewed. 195 stations have been currently renewed. 7

8 Design principles The design principles were identified in spring 2004 by a small group of experts. Hardware must be vendor independent. All kind of detectors must be connectable to the station. The software of the station must be open. Source code of all programs must be available. Hardware must be commonly available. 8

9 The data logger, software and hardware of the station 9

10 The data logger Intel PXA255 low power processor card with Linux inside. 5 RS-232, one RS-485, one USB, one ethernet and IO-lines to connect external devices. Touch screen panel to display information and to control station. Compact Flash for data storage and programs. 10

11 Detectors Genitron GammaTracer XL-3 and TechniData IGS421 for dose rate measurement. Detectors have three GM-tubes. TechniData RD203 and Vaisala DRD11A for rain detection. In future CZT or LaBr 3 -detectors or other devices. 11

12 Software All software is open license software. Data logger has MySql database and PHP-script support. All software is made using C/C++, shell- and PHP-scripts. Output file format is XML. 12

13 Communication 13

14 Communication The reliability of the network is as good as its communication. Different methods of communication were mapped in (VIRVE, GPRS, ADSL etc.). The main selection criteria were functionality and reliability. VIRVE and its packet data service were chosen. 14

15 VIRVE VIRVE is TETRA radio network for Finnish authorities. Closed network, the operator of the network is government owned company. Network is secure and reliable. Quite expensive compared to commercial GSM/GPRS operators. 15

16 Communication of the ULJAS station The station sends its results automatically every 10 minutes to STUK and to its own emergency response center. The communication solution is the VIRVE packet data. SDS message works as a backup. The same software works also in the GSM/GPRS networks (not SDS). The theoretical speed of data transfer is 9600 bd, but in reality, it is about half of that. 16

17 Current network solution Rescue/ State Provincial Offices 17

18 Benefits of network solution The communication method is TCP/IP, therefore data can be distributed to different organizations. The communication allows remote control of the station and software updates. The emergency response center acts as a back-up organization for dose rate alarms. 18

19 Improvements compared to old system Results are validated at the station -> less error alarms. New probes can detect a change of 0,1 µsv/h. The radiation situation is nearly real-time both at STUK and at emergency response centers. The hardware of the station does not limit the use of new detectors or ideas. 19

20 Validation Results are validated in four different ways at the station. 1. Probe makes validation by comparing low dose rate GM-tubes. 2. Station software makes three validations: comparison between LD GM-tubes, comparison between HD and LD GM-tubes and spikes. If validation flag is raised and the dose rate exceeds 0,4 µsv/h, the message is not treated as an alarm message. Validation reveals probe faults. Central database USVA checks if dose rate is higher than 0,1 µsv/h compared to normal background. 20

21 What next? 21

22 In the near future LaBr 3 -detector will be installed on STUK s roof for winter test. USVA-system will be renewed. 22

23 USVA USVA is system for creating, maintaining, presentation and handling of the monitoring data. USVA contains weather information (e.g. observations, forecasts, trajectories, written weather descriptions when needed.) Users connect to USVA by web browsers. USVA is guided by a consortium (Finnish Defence Forces, FMI, Ministry of interior and STUK) Will be renewed during

24 Thank You! 24