IAEA-SM-367/10/01 Environmental Sampling for IAEA Safeguards:
A Five Year Review
E. KUHN美国对华政策
D. FISCHER
M. RYJINSKI
International Atomic Energy Agency
Wagramer Stras 5, Box 100
A1400 Vienna, Austria
ABSTRACT
January 1996 marked the beginning of environmental sampling as a new safeguards strengthening measure by the International Atomic Energy Agency (IAEA). Since then, some 2000 swipe samples have been collected from over 100 facilities worldwide and submitted for analysis in the Network of Ana
lytical Laboratories (NWAL). Over this time, the program has been continuously subject to adjustments and improvements in the various areas. This paper will report on the experience gained and improvements made during the first 5 years of implementation.
The implementation of environmental sampling has moved from establishing baline signatures, to conducting routine sampling in many facilities. Initially, the IAEA concentrated on sampling at enrichment facilities and facilities with hot cells. Recently the types of locations where environmental samples are collected have expanded to include locations without nuclear material inventories, or at mining operations, as part of Additional Protocol measures.
The NWAL has expanded to increa the analytical capacity and the range of available techniques, such as Secondary Ion Mass Spectrometry, fission track analysis on highly active samples, and Scanning Electron Microscopy. The IAEA and NWAL are continuously working to improve the nsitivity of analytical techniques and quality control of analysis. In the area of data evaluation and management an ORACLE databa has been developed and put into operation, and the evaluation procedures and reports have been largely standardized. Although the IAEA has experience in collecting and analyzing veral forms of samples such as water, vegetation and soil, swipe sampling has become the preferred method of sampling. Sampling tools have been refined bad on
inspector and laboratory experience. Sampling procedures have improved through the incread u of composite sampling, which results in fewer samples and a reduction in the analytical workload. Further study has been done in the area of air sampling, a sampling method propod for wide area environmental sampling (WAES). A Multi-Member State Support Program project evaluated the technical feasibility and costs associated with WAES. Bad on its conclusions, an initial air sampling field trial was conducted against reprocessing operations. At this time, analysis results are not complete but an overview of the trial and latest results will be prented. Additional air sampling field trials are planned to be conducted against an enrichment facility.
INTRODUCTION
什么无味One of the new safeguards strengthening measures implemented by the International Atomic Energy Agency (IAEA) is environmental sampling. Environmental sampling for safeguards is bad on the premi that every nuclear process, no matter how leak tight, emits small amounts of process material to the environment. This material can ttle on equipment and surfaces within the buildings and can be transported outside to deposit on vegetation or soil or be carried into the water systems. The quantities of nuclear material emitted are well below concern from a health physics and safety standpoint; however, analytical techniques exist that can detect and
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measure the extremely low levels of nuclear material which are indicative of the process from which they derive.
The power of environmental sampling for safeguards was demonstrated through a ries of field trials conducted during the IAEA’s development programme to systematically evaluate a strengthened and more cost-effective safeguards regime ('Programme 93+2') [1,2]. The overall conclusion from the field trials, conducted in and around 12 nuclear facilities, was that the analysis of environmental samples collected in the immediate environment of a nuclear process or site can provide an effective tool for incread assurance of the abnce of undeclared activities at the site. In 1995, the IAEA Board of Governors approved the implementation of environmental sampling as a new safeguards measure. The initial implementation of environmental sampling is focud on swipe sampling in enrichment plants and in installations with hot cells [3,4]. Bad on the experience from swipe sample collections and the analytical results, the sampling procedures have been modified. Furthermore, an environmental sampling databa was developed and is in operation to facilitate the data evaluations.
A major milestone was reached in the development of a strengthened safeguards system when in May 1997 the IAEA Board of Governors adopted the Model Protocol Additional to Safeguards Agree
ments, INFCIRC/540 (Corrected). The Additional Protocol expands the IAEA's legal authority with provisions for additional information to be provided by States on their nuclear and nuclear-related activities and for broader access by IAEA inspectors to locations in States. The Model Additional Protocol greatly adds to the value of collecting environmental samples through incread access for inspectors. In addition to the so-called location-specific application of environmental sampling, the Model Additional Protocol also provides for the future application of environmental sampling in a monitoring or wide-area mode. Procedures to implement wide-area environmental sampling require approval by the Board of Governors.
This paper reports on the status of the Agency’s environmental sampling programme for safeguards after five years of implementation, describes recent developments in sampling procedures and in the establishment of a central data ba, and identifies future needs required under the Model Protocol Additional to Safeguards Agreements [5].
IMPLEMENTATION OF ENVIRONMENTAL SAMPLING
Since sample collection began in January 1996, the priority has been on the establishment of a baline environmental signature for each facility. In this pha, swipe samples are collected from fa
cility locations identified as having the greatest potential for containing traces of past and current operations. The measurement results from laboratory analys of the samples are ud to characterize the nuclear signature for the facility. Once the baline is established, requirements for sampling as part of routine activities can be determined. By mid-2001, swipe samples have been collected at 104 facilities under safeguards agreements. Sampling as part of routine inspections and design information verification visits, as well as under arrangements provided for by Additional Protocols began in 1998.
NETWORK OF ANALYTICAL LABORATORIES (NWAL)
In addition to the IAEA's Clean Laboratory for Safeguards, specialized laboratories in four Member States with capabilities to analyze environmental samples were certified initially as network laboratories. This network has been and will continue to be expanded. Secondary Ion Mass Spectrometry (SIMS) is now considered a routine analysis method at the IAEA's Clean Laboratory, as well as at three additional Member States' laboratories. One new laboratory is in the process of final certification for newly established capabilities in particle analysis by Thermal Ionization Mass Spectrometry (TIMS) in combination with fission track particle screening. Another new laboratory is prently being certified for analysis of samples by Accelerator Mass Spectrometry (AMS). Another
Member State is in the process of establishing a new clean laboratory facility for the analysis of environmental samples. In this ca, the laboratory and the IAEA are working in clo cooperation at the technical level and the laboratory is expected to join the network once it begins routine operation. ENVIRONMENTAL SAMPLING DATABASE
Measurement data from the laboratory analysis of the swipe samples at the IAEA Clean Laboratory or in the Network of Analytical Laboratories are reported to the Department of Safeguards where they are evaluated and compared to the expected nuclear signature for the facility sampled. To allow for the amless integration of sample data from multiple analytical laboratories and safeguarded facilities, the IAEA developed an Environmental Sampling (ES) databa. The ES databa rves as a tool for analysts in evaluating individual sample ries, or investigating trends by country, facility-type, or sample-type (Figure 1). Current development efforts focus on the ur-interface with an emphasis on improving arch capabilities and standardized reports.
The development of the databa consisted of veral major steps: developing the structure that organis the data; developing the ur-interface; migrating the older data to the new databa; back-filling data from previous data ts; and developing output reports. The ur-interface retrieves data for a single sampling campaign, as well as arches by country, nuclear activity, facility type, ne
twork laboratory, and all samples falling within a certain year. More complex data queries require the ur to enter a query using Oracle command syntax. The ur form currently has six active tab pages. The first tab page contains sampling campaign information, followed by sample location and screening information on the next page. Each analytical technique (TIMS, SIMS, High Resolution Gamma Spectrometry and Isotope Dilution Analysis) has an individual tab page to display the analytical results and is linked to the active ries on the first tab page. The analytical data can be exported to a file with the push of a button for plotting or further data manipulation. Besides evaluating sample data, the databa also aids the ur in evaluating Quality Control data and comparing data to known standards.
Reports
Country
Overviews
Facility
QC
Reports
Analytical
Figure 1. Environmental Sampling Databa Schematic
The IAEA migrated the older environmental sampling data from a MS-Access application to the Oracle application. Although the Oracle platform offers robustness and advanced curity capabilities not available in the original MS Access databa, the Oracle development has proven a challenge. The design of the first generation ES databa was completed and became operational in
early 2000. Future development efforts are focusing on improving the functionality of the ur-interface and data sharing with other databas within the Agency.
SAMPLE COLLECTION PROCEDURES
In general, samples are taken by trained inspectors using standardized sampling kits and approved sampling protocols according to the facility-specific sampling plans. Bad on the experience from baline swipe sample collections and the measurement results from sample analysis, sampling procedures have been modified. For most sampling locations cotton swipes are ud (Figure 2).
The standardized cotton swipe kit is pre-labeled with an IAEA identification number and normally contains ven cotton swipes individually packed in mini-grip bags. A kit also includes larger mini-grip bags for double bagging, labels, two pairs of clean-room gloves, a pen, and a sample collection sheet with sampling instructions. The cotton swipe material has a low uranium background, is durable and is relatively easy to process for analys.
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Figure 2. Standardized Cotton Swipe Kit (one sample)
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A different sampling kit is ud for sampling within hot cells. Bad on the field experience and recommendations provided by the operator of a hot cell facility, the original sampling tool has been redesigned. The original tool was relatively large and required a large amount of lead shielding for shipment. Furthermore it could not be ud in pneumatic transfer systems. The new sampling tool, consisting of small cellulo wipes and plastic bottles that can be ud in pneumatic transfer systems, has been successfully ud in all hot cell facilities since its implementation (Figure 3). It is smaller for easier introduction into and removal from the cell, and requires less lead shielding.
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bottles
Working
pen
Figure 3. New Hot Cell Sampling Kit (one sample)triace
Initially many point samples were taken for each sampling campaign. Lately mainly composite samples are collected from larger areas in a sampling location. This procedure allows a reduction in the number of samples collected and subquently optimizes the analytical effort without sacrificing nsitivity in detecting signatures of nuclear operations.
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