GIS and satellite images in nuclear safeguards

Transcription

1 GIS and satellite images in nuclear safeguards A. Poucet, S. Contini & F. Bellezza European Commission, Joint Research Centre Institute for the Protection and Security of Citizens Ispra, Italy Abstract Nuclear safeguards are a set of complex activities performed to ensure that nuclear material used for peaceful purposes is not diverted for the construction of nuclear weapons or other explosive devices. This control requires the use of powerful support systems to collect, retrieve and analyse the large amount of information involved. This paper, after a brief introduction of the main concept of nuclear safeguards, shows the benefits of using Geographcal Information Systems to develop support tools for declaration and verification. The important role that satellite images can play in the verification process is also considered. 1 Introduction The nuclear material that is being used in the civil nuclear industry to produce electricity is constantly safeguarded to avoid its diversion for the construction of nuclear weapons. This control is performed by the International Atomic Energy Agency (IAEA) in 188 states that voluntarily joined the Non Proliferation Treaty (1970). The signatory states accepted to periodically declare their nuclear facilities, as well as on site inspections and the control of nuclear materials inventory. Following the discovery of parallel nuclear undeclared activities in Iraq, just after the Gulf War, the IAEA recognised the need to strengthen the safeguards system and in 1997 an additional protocol was approved. This protocol asks for the declaration of all nuclear fuel cycle related activities, including research and developments not using nuclear material and an extended access to facilities. The requirements set up in the additional protocol give to IAEA a greater amount of information to verify the completeness and coherence of declarations.

2 146 Management Informacion Systems To deal with the additional information, the development of powerhl support systems becomes a primary concern. In this process Member State need a system for supporting the declaration process, whether IAEA needs a system to support verification of states declarations using in-house and open source information. A relevant percentage of this information is spatially referenced, i.e. it can be characterised by its location on the Earth. Therefore a Geographical Information System (GIS) represents the natural working environment for transforming this large volume of data into usable information. During the last two years we have implemented SIT (Site Investigation Tool), a GIS-based software to support declaration and verification activities. Ths tool is at an advanced stage of development and it is currently being tested by IAEA and by some countries. In 1998 IAEA promoted an investigation on the feasibility and costeffectiveness of the use of commercial satellite images as a means to support the implementation of safeguards. The results achieved confirmed that medium to high-resolution satellite imagery represent an important source of information for site verification and, more generally, for monitoring nuclear activities. The aim of this paper is to describe the current state of the art in the use of GIS and satellite images in nuclear safeguards. 2 The nuclear fuel cycle All activities associated with the production of electricity from nuclear reactions constitute the Nuclear Fuel Cycle (NFC), which is schematically represented in figure 1 [l]. Enrichment Fuel fabrication Power generation 4 4 Figure 1 : Nuclear fuel Cycle schematic diagram The NFC starts with the uranium mining and milling. Uranium ore is extracted from open pit or underground mines, depending on how deep is the deposit. The content of uranium in ore ranges between 0.1 to 1%. Milling operations - which are generally carried out close to mine to reduce shipping costs - separates uranium from the waste rock giving uranium oxide (U~OP), which contains more than 60% uranium. With conversion U308 is converted to either uranium dioxide (UOZ)- used in those reactors that do not need enriched uranium, e.g. the Canadian CANDU

3 Management Information Systems 147 and Gas-cooled reactors - or uranium hexafluoride (UF6), to produce fuel for reactors that use enriched uranium, e.g. Light Water Reactors. Natural uranium contains two isotopes: 235U and 238U. In order to sustain the fission chain the content of 235U has to be increased from 0.7% to 34%. This increase is obtained in enrichment plants. Within fuel fabrication plants enriched UF6 is converted to uranium dioxide (U02) powder and pressed into small cylindrical pellets. These are loaded into tubes to form fuel rods, which are then assembled in clusters to form fuel elements for use in the nuclear reactor core. A looomwe power plant uses about 75 tonnes of fuel each year. Inside a nuclear reactor the fission chain generates heat. This heat produces steam, which is then used to drive a turbine connected to an electric generator. During fission, 235U atoms are consumed. With time the concentration of fission fragments increases to a level that it is no longer convenient to continue to use the fuel. The spent fuel contains about 3% of waste products, 1% of plutonium and 96% of uranium with a concentration of 235U less than 1%. About one third of the spent fuel is removed every year and replaced with fresh fuel. The spent fuel discharged from the reactor emits radiation and heat. It is therefore stored for at least five months into a large pool of water - the spent fuel storage - to allow the radiation level and the heat being released to decrease. In a reprocessing facility uranium and plutonium are separated from the waste and then separated from each other. Uranium and plutonium are used for producing new fuel. The fission products and other waste are sent to the waste disposal. 3 Nuclear safeguards All fissile materials must be safeguarded due to their potential use for the production of nuclear weapons. Nuclear safeguards encompass the measures designed to deter, prevent, detect, and report actions aimed at diversion of nuclear materials. Measures are applied to match both the domestic and international concerns [3]. Domestic safeguards are implemented by individual states to prevent the theft of nuclear material or the sabotage of nuclear facilities that might threaten the public. Measures taken range from real time material surveillance to material accounting. International safeguards, which are implemented by the International Atomic Energy Agency (IAEA), address the concern of the world that proliferation of nuclear weapons can occur. The international safeguards system has been developed on the basis of treaties, the most important of which is the Non-Proliferation of Nuclear Weapons Treaty (NPT, 1970). The NPT signatory states voluntarily accept IAEA inspections for the exclusive purpose of verifying that the nuclear material is not diverted to nuclear weapons or other explosive devices (INFCIRC/153, 1971 [2]). To this purpose IAEA performs on site inspections and independent verification of nuclear material accountancy reported by states, to detect anomalies that might be caused by diversion. Containment (sealing) and surveillance systems are used

4 148 Management Information Systems to reduce the inspection frequency for the material that is stored for a certain period of time. The discovery of parallel nuclear undeclared activities in IRAQ, just after the Gulf War, pushed the IAEA to propose to strengthen the safeguards system with new requirements set forth in the additional protocol INFCIRCh40 [3]. States signing this new protocol have to declare their nuclear fuel cycle-related research and development activities not involving nuclear material (R&D), Mines and Concentration plants, source material, material exempted from traditional safeguards, import/export of equipment of nuclear interest. Furthermore, the use and content of all buildings in nuclear sites have also to be declared. With the entry into force of the additional protocol the IAEA verification approach is undergoing a process of change, due to the need to integrate the requirements set up in both INFCIRCI153 and INFCIRU540. The new approach, referred to as Integrated Safeguards System, is under development and will lead to a redesign of the nuclear materials accountancy system. With the new approach IAEA will have a greater amount of information to perform correctness and completeness verifications both at site level and at country level. At site level correctness and completeness are intended, respectively, as the verification that all installations and activities correspond to the declarations provided and that there are no undeclared activities or installations at the site. At country level, correctness means the consistency of all declared fuel cycle activities, whereas completeness is the verification that there are no undeclared installations or activities in hidden sites. The huge amount of information to be dealt with by the states and by the Agency required investigations on the applicability of new data sources and new information technologies to support both the declaration and verification activities. To this aim satellite remote sensing and GIS and have been recognised as being very helpful. 4 The verification process Figure 2 is a schematic diagram of the new verification process [4,5]. On the declaration the Agency's quality control procedure is applied to verify the conformity with the agreed protocols. In case of incoherence or insufficient details, additional requests are made to the State. Declared information can be organised into three interconnected models: Topological, Functional, and Operational. The topological model comprises all geographically referenced data represented at country and site levels. At country level the main thematic map is the site location. At site level several thematic maps are considered, e.g. site layout raster map, boundary of Facilities and related Plant Units, Material Balance Areas (areas where the nuclear material is handled), the location of the associated Key Measurement Points (key points where the nuclear material is measured), buildings layout, etc. In the technicalfunctional model the information concerns the description of nuclear facilities, i.e. processes, technical characteristics of the installation, materials used and procedures, material flows, material balance areas and related key points of measure, procedures, etc.

5 Management Information Systems 149 The operational model contains information about the operational program at site level (e.g. overall production numbers, operating schedules, modification or construction activities) and at facility level (e.g. outages, refuelling schedules). The declared mformation is then compared with observations. This may lead to the identification of incoherence between observed and declared data. Information used for verification range from specialised databases, specialised journal, magazines, web pages, scientific literature, in-house databases, fuel cycle models, inspection reports, remote monitoring, etc [6]. Satellite images and the cartography of the area around the site are used to verify the declared topological model. Figure 2: Site verification scheme Once all site declarations have been assessed, a certain number of verifications can take place at the country level in performing the correctness and completeness checks. In figure 3 the conceptual approach for country level assessment is represented. Again, parameters could be forecasted on the basis of a fuel cycle model and compared with observations. In addition to detection of anomalies, other information sources may provide hints that some activities are going on that are related to the nuclear fuel cycle but are not part of any declaration. 5 Commercial satellite images for verification The investigation on the potential technical applications of commercial satellite images as a means to support the implementation of safeguards was promoted by IAEA in 1998 [7]. The results achieved in this project confirmed that satellite imagery could be useful for various purposes.

6 150 Management Information Systems, I cvcle I I m he1 c cle L i;: Figure 3: Conceptual approach for Country level assessment Several other investigations using practically all types of active and passive sensors from commercial satellites followed, which further contributed to better clarify the applicability of different satellite images to [8,9]: - - verify the declared site layout maps; detect undeclared activities, e.g. new mining activities, the construction of new sites and facilities, etc.; - monitor changes at decommissioned facilities; - assist in inspection planning and reporting; - monitor the status of a facility. In particular PAN SPOT / IRS-lC, respectively with spatial resolution of 10m and 5m are useful for corroborating open source information on suspected non-declared site or activities; high resolution satellites, such as KVR-1000 (2m) and IKONOS (lm), are suitable to verify the declared site layout and in planning on site inspections. As shown in figure 4 high-resolution images (SPIN-2, and particularly IKONOS) allow distinguishing many detailed features of a site such as buildings, process tanks, etc. These images are also useful in characterising the site surroundings and to extract or confirm the main thematic information related with infrastructures and land cover. Change detection analysis helps inspectors to identify undeclared activities in nuclear sites. Images with lower resolution provide the possibility to cover relatively large areas with sufficient detail and at acceptable costs. They can be used to identify areas where suspected undeclared nuclear activities are taking place. These areas are then further examined with high-resolution images.

7 SAR images are also useful for those sites near the Polar Regions when the night-time is too long to wait for the light time. Moreover, SAR is the unique solution for areas with frequent cloud cover. Some years ago also the arms control community started to consider the satellite remote sensing as a useful mean for monitoring nuclear activities [9]. The possibility to apply high-resolution satellite images have been shown in the frame of the verification of the (future) Fissile Material Cut-off Treaty (FMCT) [lo], where the aim is to identify the shutdown status of plants used to produce fissile material for nuclear weapons. The plant status can be ascertained from the steam flowing from the refrigerating towers (see second image of figure 4) and from the temperature of the discharged water. Another interesting use of medium to high-resolution satellite images is in the exact location of underground nuclear explosions [ Management Information Systems The role of GIS for declaration and verification With the integrated safeguards system, IAEA inspectors have now to analyse a huge amount of information. States declarations are verified against in-house data, inspection reports, nuclear Figure 4: Some example of high-resolution satellite images used in treaty verification fuel cycle knowledge base, satellite images, press, scientific literature, etc. This information is quite diverse and dispersed, ranging from text, numerical data,

8 152 Management Information Systems images, drawings, maps, etc, and a relevant percentage of it is spatially referenced. It follows that a Geographical Information System is the suitable environment for developing support tools for declaration and verification, able to integrate data of different type and format, and located in different places. To this aim we have developed SIT (Site Investigation Tool) for supporting both declaration and verification activities. SIT, which implements the concepts shown in figure 2, uses ESRI ArcView and Image Analysis extension for Windows [ 121. The first step of the declaration is the representation of all sites on the country map. Then nuclear site maps are scanned, imported and geo-referenced. Ground control points can come from a satellite image or taken from a GPS- Global Positioning System. The Universal Transverse Mercator has been used as the co-ordinates system for geo-referencing all sites in the world. Thematic vector maps can easily be generated using the raster site map as background. Declarations are then associated to the features of the related thematic map. The need to deal with a large amount and variety of documents of the topological, functional and operational models as well as to query localiremote databases on e.g. material accountancy, and to run external models, required the development of ad-hoc modules embedded in the GIs. In particular the integration of a Document Management Module with the GIS makes the data storage and retrieval (from maps) particularly simple and flexible. SIT allows the user to associate any feature with any type of document, any SQL and any external application as schematically represented in Figure 5. Documents I NFCl RC/540 declaration n Figure 5: Information that can be associated to any graphical object in SIT Except for some modules specific for declaration, the architecture of SIT for verification is very similar. Differences mainly concern the data analysis module

9 ~anagement Information Systems 153 and the use of satellite images. Image analysis tools can be used e.g. to compare the site layout map with a satellite image in order to identify possible discrepancies between the declaration and the real situation, as well as to detect site infrastructure changes with time. An example of the use of SIT is given in figure 6. It concerns the use of an Ikonos image to verify a site map. The site map is geo-referenced with GCP taken from the image and made transparent. Mismatches between the map and the image can be represented with different colours to highlight e.g. unclear objects, undeclared buildings, buildings that are represented in the map but not in the image, and vice versa. Furthermore, the change detection analysis applied to different declared maps and images helps the inspector to identify changes in site infrastructures. This information is then used to plan the next on site inspection. Figure 6: Example of a site map verification with high-resolution satellite images Satellite images and spatial data analysis can be used to identify areas most likely to contain nuclear activities. The analysis can be based on key indicators such as: - Proximity to water, roads, rails; - Proximity to populated places (Remoteness); - Indications of land-use change; - Slope parameters (Low-to-High degrees); - Power requirements; - Site area requirements.

10 154 Management Information Systems 7 Conclusions With the entry into force of the additional protocol to safeguards both the states and the Agency have to deal with a huge amount of information. In few years several proposals have been made on how to perform correctness and completeness verifications of states declarations. To this aim the benefits that can be obtained from the use of Satellite images and Geographical Information Systems have been shown. The SIT system we have developed integrates data of different type coming from different sources. This tool will be further developed in collaboration with IAEA and some states. 8 References R.A. Knief, Nuclear Engineering, Second edition, Taylor & Francis, The Structure and Content of Agreements between the Agency and States required in connection with the Treaty on the Non-Proliferation of Nuclear Weapons, IAEA INFCIRC 153, June Model Protocol Additional to the Agreement(s) between State(s) and the International Atomic Energy Agency for the Application of Safeguards, IAEA INFCIRC/540, Vienna Poucet, A., Integration of Information in the Context of the Strengthening of Safeguards System, ESARDA Seminar on Modem Verification Regimes, Helslnlu May, A.Poucet, S. Contini, Use of Geographical Information Systems and Satellite Images for Safeguards, Proceedings of the ESARDA Seminar on Strengthening of Safeguards: Integrating the New and the Old, Dresden, Germany, EUR Report 19587,2000. K. Chitumbo, M. Nicholas, The Role of Diverse Sources of Information in Safeguards, same as [5]. IAEA Technical Workshop on Safeguards: Sources and applications of Commercial Satellite Imagery, Vienna, September, Q.S. Truong, Potential Applications of Commercial Satellite Imagery in International Safeguards, same as [5]. B.Jasani, Commercial Remote Sensing Satellites and Security Implications, same as [5]. [ 101 H. Zhang, Civile Remote-sensing Satellites and a Fissile Material Cut-off Treaty: Some Case Studies on Verifying Nonproduction, JNMM M.J. Canty, B. Jasani, J. Schlittenhardt, Wide Area Change Detection with Satellite Imagery for Locating Underground Nuclear Testing, Symposium on International Safeguards, Verification and Nuclear Material Security, Vienna, November, A. Poucet, S. Contini, F. Bellezza, A GIS based System for Declaration and Verification, Symposium on International Safeguards: Verification and Nuclear material security, Vienna, Austria, 2001.