Rainer Dielmann, Walter Bürkin Genitron Instruments GmbH, Frankfurt, Germany

Transcription

1 Adequate Technologies for Wireless real-time dose rate monitoring for off-site emergency management An experience report based on the Off-Site Emergency Preparedness (OSEP) activity, Tacis project Establishment of early warning systems around the Kursk, Kalinin and Balakova NPPs in Russia and connection to Moscow crisis center Rainer Dielmann, Walter Bürkin Genitron Instruments GmbH, Frankfurt, Germany Abstract. At a nuclear disaster the efficiency of emergency management on-site as well as off-site is closely connected to the quality and reliability of the actual status information. Reliability and short response time of the data communication path are important in the early phase. In order to protect investment and minimize TCO (Total Cost of Ownership) the dose rate measurement systems should also be adequate for the later phase emergency management and rehabilitation of contaminated areas. Based on three years experience the pros and cons of available GSM / GPRS / UMTS / TETRA (Terrestrial Trunked Radio) and satellite based technologies are compared with SkyLINK - a proprietary wireless network which is fully owned by the supervising authority or a nuclear installation. The European Commission s decision to opt for this state-of-the-art technology within the TACIS program fulfills highest standards in terms of: (1) independency of public communication lines, (2) good data availability also in rural areas and in emergency scenarios, (3) fast installation, system startup and training all done in up to 3 days, (4) extreme mobility in emergency cases, (5) high flexibility for changing tasks, (6) a very high degree of autonomy, (7) low operating and maintenance costs over a ten year lifetime, (8) longterm reliability of probes and data management system. The GammaTRACER / SkyLINK systems installed around three Russian NPPs are operated by the concern Rosenergoatom. They are one example of other systems on a worldwide scale. Key words: emergency management, data communication, Total Cost Of Ownership, proprietary wireless dose rate network 1. Requirements At a nuclear disaster the efficiency of emergency management on-site as well as off-site is closely connected to the quality and reliability of the recent status information. Reliability and short response time of the data communication path are important in the early phase. In order to protect investment and minimize TCO (Total Cost of Ownership) the measurement systems should also be adequate for the later phase emergency management and rehabilitation of contaminated areas. The following characteristics are of special interest : 100 % availability of data transmission and short delay time, even in a catastrophic scenario. Independency of public communication services is advantageous. Availability of the communication link even in rural areas, with poor cellular communication infrastructure. Independency of mains power. Even the use of solar panels could decrease system availability (pollution, vandalism). A built-in battery supplying the power for the whole system life (10 years) would be advantageous. Light weight and fast installation would allow easy re-organization of the measurement sites, specially in the later-phase management or contaminated area. The annual overall operation cost - including maintenance and telecommunication fees - should be close to zero. 1

2 2. Available Communication Technologies GSM / GPRS / UMTS Pros : Cons : - «Commercial off-the-shelf «technique, relatively moderate initial investment - Poor availability in rural area - Decrease of transmission reliability at emergency scenario - Permanent fee for data transmission - High power consumption, solar panel needed TETRA (Terrestrial Trunked Radio) Pros: Cons: - High availability even in emergency scenario - No fee for data communication - Poor coverage, high infrastructure costs - High power consumption, solar panel needed Satellite based technologies Pros : Cons : - High availability even in emergency scenario - Very good area coverage - Very high fees for data transmission - High power consumption, solar panel needed - Varying transmission delay times, depending on provider - Questionable protection of investment (due to lots of bankruptcies) SkyLINK : Customer-owned proprietary wireless network Pros: Cons: - High availability even in emergency scenario, 1 minute response time possible - Good coverage, also in rural areas (the extremely sensitive receiver covers a radio horizon of up to 100 km) - No fee for data transmission - Extremely light-weight and mobile - independent of mains and solar power (up to 5 years battery life) - Initial cost of receiver station demands for at least 10 measurement points 3. TACIS Project : 3 years of experience with SkyLINK / GammaTRACER 3.1. System Design In the year 2000 the power plants of Balakova, Kursk and Kalinin were equipped with a SkyLINK radio system and 12 GammaTRACER probes each. A system based on GSM or similar cellular communication networks was not applicable due to insufficient infrastructure. The probes are located in a 30 km circle around the NPPs. All data is available at the NPP and additionally transferred to the Rosenergoatom crisis center in Moscow Installation The overall installation, system startup and training took three days for each NPP. The 12 GammaTRACER probes were installed in 2 days from NPP personnel. 2

3 3.3.Availability of the radio link All sites are successfully linked. There has been no degradation of the data reception due to seasonal or weather effects Response time, periodical emergency tests The probes are set to 1h-measurement cycle, with automatic change to 1 min if an alarm threshold for dose rate is exceeded. The measured delay time is max. 3 minutes Maintenance, off-time and long term reliability of probes and data Up to now there was no malfunction of the GammaTRACER probes and SkyLINK system. In the same time period other systems installed in the other Russian NPPs periodically failed due to problems with the power supply. 4. Conclusion The SkyLINK / GammaTRACER system reaches best results concerning the requirements of nuclear surveillance systems (cost efficiency, reliability and flexibility). The 3-year experience report of the Russian NPPs Kursk, Balakova and Kalinin proved the sophisticated specifications and long-term-reliability of the system. Table 1. TCO comparison: SkyLINK proprietary radio network vs. GSM Basis: Nuclear plant surveillance network 40 probes GammaTRACER BASIC Cycle 1 h, 10 year lifetime Cost type SkyLINK Competitive Technology GSM TX 1 hr GSM TX 24 hrs Purchase cost 112 % 100 % 100 % Installation cost 30 % 100 % 100 % Maintenance cost 24 % 100 % 100 % Regular fee 15 % 600 % 100 % TCO (10 years) 83 % 155 % 100 % radio horizon up to approx. 100 km maintenance-free long term operation for at least 3 years 2 Geiger-Muller counter tube probes (20 nsv/h 10 msv/h, optionally 10 Sv/h) measurement cycles min storage capacity measurement points (3 y in 1 h-measurement cycle) transmitting power only 10 mw FIG. 1. GammaTRACER autonomous radio probe A compact and mobile measuring station to be mounted within minutes at existing infrastructure 3

4 FIG. 2. Without direct human intervention a GammaTRACER probe can easily be dropped at any contaminated terrain. FIG. 3. SkyLINK maintenance-free network with 12 probe locations within a 30 km radius around the Russian Nuclear Power Plant of Kalinin operating since the year

5 FIG.4. SkyLINK mounted in transport racks for mobile use. Set into operation within 15 minutes FIG.5. Radio coverage in urban area. This link tests were performed in Paris with distances up to 20 km and more. 5

6 An example for a mobile application in emergency management in German nuclear power plants A SkyLINK system can be used for both, routine measurement tasks as well as in emergency management. In order to make optimal use of the mobile functionalities the complete system (receiver and primary data center is integrated into one, two or three portable transport racks which can comfortably be built into a van. For operation the antenna and the downconverter are fixed on a 10 meter telescope mast. The SkyLINK system however is not bound to the use in an emergency van: Within shortest time any tent or bureau can serve as an operation center. Likewise GammaTRACER probes can be placed at adequate locations. The benefit of this mode of operation is that this system can be run in nearly any place and by any operator. FIG.6. Surveying nuclear power plants in the German State of Schleswig-Holstein. Data of 82 probes with distances up to 85 km are collected using proprietary radio technology. High availability and integrity of data is guaranteed. The flexibility of a proprietary network with autonomous probes allows integration into existing network structures. This means it can be operated within conventional wire bound setups, a combination with satellite or GSM transmission. 6