DECONTAMINATION AND DECOMMISSIONING (D&D): A PROBLEM OF LARGE (BUT DEFINABLE) DIMENSIONS

Transcription

1 DECONTAMINATION AND DECOMMISSIONING (D&D): A PROBLEM OF LARGE (BUT DEFINABLE) DIMENSIONS Ray Lawson, Blue Ridge Metrology, Inc. Gary A. Benda, U. S. Energy Corp. ABSTRACT The U. S. Department of Energy has a requirement for facility deactivation and decommissioning of more than 7,000 buildings contaminated with radioactive and hazardous materials. Technology development is a key aspect of effective performance of facility transition and is focused in five areas: facility a characterization, facility decontamination, facility dismantlement, material disposition, and worker safety. Current appropriations for Defense Facility Closure that includes significant funding for Deactivation and Decommissioning are running on the order of $1.1 billion per year. Clearly this is a long-term, high cost requirement that represents significant opportunity for const savings by prudent management actions and technology innovation. Recent technology advancements in measurement, imaging, and design development technology may assist DOE significantly in these efforts. Such a large number of complex facilities represent an enormous challenge for DOE to properly characterize, decontaminate, dismantle, and dispose of the material while guarding the safety of workers and the public. The uncertainty of the configuration and status of the facilities complicate the size of the problem. The obvious benefit of the successful nuclear non-proliferation efforts has made the requirement for facility D&D transient and more complex. The Department has undergone substantial reorganization and this has resulted in changes in both the custodians and the mission at facilities slated for D&D. DOE s Orders for D&D of its facilities requires that the size and complexity of each facility project be defined so that effective management practices can be employed. Laser based three dimensional imaging provides the tool to five DOE s project teams accurate, to-scale, complete, and high-utility images that can be readily used (within standard software environments) to define the size, nature and complexity of the facilities targeted for D&D. INTRODUCTION How Laser Based Three Dimensional Imaging Works Facility mangers and engineers have struggles throughout the history of the nuclear industry with the daunting task of configuration management and numerous challenging metrology tasks. Laser imaging, has been made possible by recent breakthroughs in the areas of laser ranging and ultra-precise clocking, rapid coordinate acquisition, mathematical regression of large data sets and transparent integration of innovative and standard design software. Laser imaging instrument developers have integrated standard design software. Laser imaging instrument developers have integrated breakthroughs in

2 these three areas to produce a technology that allows rapid, real time, accurate, fully three dimensional imaging of existing facilities and equipment. This technology is often referred to as LIDAR for Light Detection and Ranging. The imaging is captured and processed in three steps. 1. The LIDAR scanner captures the image as a set of points of defined coordinates (called point clouds.) 2. The point cloud images are run through an initial processing that uses regression and other mathematical modeling techniques that converts the point clouds to geometric shapes that represent the facility (planes for walls and floors, cylinders for pipes, tanks and tubes ). 3. The geometric model is then transferred through an interface where the geometric model is translated to an end form of the user s specification. Available forms include standard engineering floor plans, elevations, reflected light plans, and/or fully three dimensional models that can have any degree of graphical processing including coloring, texturing, or annotation with data, such as radiological survey results. When the final image form is produced, it can be manipulated in any manner that the base software (e.g. CAD or D-D studio) allows. These manipulations support applications such as design modification, volume calculations for waste generation estimates, or design comparisons that could be sued for progress assessments during disassembly or modification projects. The current operational limits of LIDAR imaging technology are favorable for application in industrial environments including nuclear facilities. Current vintages of scanners can capture points at rates between 2,ooand 100,000 points per second and, in long-range mode are accurate to a maximum deviation of +/-0.25 inches at the maximum distance of 1500 feet. The accuracy and quality of the image produced depends on a number of variables that can be specified by the user to meet his ultimate project goals. To understand some of the variables that influence performance, users must understand some of the mechanics of how the measurements are made. Industrial LIDAY works by calculating 3-D coordinates based on the distance from the LIDAR scanner to the object and the vertical and horizontal angels used to direct the laser. The scanner emits a laser pulse and measures the time required for the laser pulse to strike the object and return. From time-of-flight, the distance to the object is calculated. The software integrated into the scanner combines the time-of-flight measurement with the horizontal and vertical angles to determine the coordinates of each point in the scan. These points produce a 3-D image of the object.

3 The operational variables for scanner operation are the distance, horizontal and vertical angle steps, and the laser configuration. This type of imaging can be customized to meet the project objectives by trading speed for distance and smaller increments of scanner pulse steps. Smaller scan increments could improve accuracy and image clarity, but extend the time to scan and create voluminous data sets that tax both processor and software capabilities. The bottom line is that a wide range of scanners are available with a band of accuracy and range appropriate to achieve imaging objective tolerances from in. to 0.25 in. Decreased range and speed are associated with the higher accuracy applications. HISTORY OF APPLICATION Industrial LIDAR has been successfully used in a wide range of application including asbuilt drawing of factories and re-engineering if pharmaceutical plants, petro-chemical facilities, food manufacturing processes, pulp and paper mills, crime scenes, aircraft, ships, automobiles and nuclear facilities. The data generated with industrial LIDAR is traceable to NIST standards under a proprietary process developed by Blue Ridge Metrology. Data and facility images generated by industrial LIDAR have been used in litigation and withstood the scrutiny of the courtroom. Industrial LIDAR has been applied extensively in nuclear facilities for applications ranging from facility imaging to precise component installation and alignment. It has proven successful for imaging of process critical components such as fluid transfer lines, ice cages for emergency cooling, and for replacement of steam generators. APPLICATION TO DEACTIVATION AND DECOMMISSIONING The basic compatibility of this technology with the types of information that DOE and the nuclear community need make it inherently attractive for DOE application. DOE s Orders require that facility managers pursuing deactivation and decommissioning of a facility address the following. 1. Definition of the size and complexity of the problem 2. Physical asset identification, inventory and management 3. Maintenance of configuration documentation and integrity 4. Evaluation of facility status in terms of current mission needs and appropriate scope 5. Use of process tools, such as value engineering to improve efficiency and costeffectiveness 6. Project technical and organizational interfaces 7. Actions to identify and characterize hazardous and radioactive materials and wastes remaining in systems/facilities and means to provide for their stabilization and/or disposal 8. Conducting surveillance and maintenance activities to support #7 (above) 9. Establish a baseline for physical, chemical, and radiological characterization and update as necessary to maintain currency with facility modifications

4 10. Evaluate alternatives that have been identified previously for deactivation and decommissioning and identify (through a defensible process) a preferred process 11. Pursue a defined method for detailed engineering planning and for plan documentation to execute the preferred deactivation and/or decommissioning alternative. Another potential benefit for use of this technology is the statutory requirement for historical preservation. Many of the facilities under consideration for D&D are historic for their role in development of nuclear technology and production of the United States nuclear deterrent. Rendering these facilities available to the public to witness their historical significance is problematic due to the radiation fields associated with some of them. Accurate images of the facilities would provide a way to preserve these facilities virtually for their historical significance with risk of exposure to the related hazards. Industrial LIDAR imaging may have its greatest utility in waste management and minimization, one of the most challenging areas of D&D. LIDAR images can be used to determine the volume of wastes that would be generated form D&D operations like scabbling. The image could be annotated with radiological characterization data to define both the volume and class of waste that would be generated. Such modeling would help make estimates for D&D operations and waste disposal more accurate. LIDAR images could also be used to optimize dismantling and disposal operation for equipment and components of facility infrastructure. The accurate volumetric images of the components could be used to determine cutting pattern for the equipment and structures being dismantled. Once an optimal dismantlement process was performed, the images could then be used to maximize the density of packing of large equipment and dismantlement products. Given the very high cost of radioactive material disposal, optimal density packing could produce significant savings in waste disposal costs. Whereas cost reduction is rightly a significant goal of DOE s mission, worker safety (especially radiological protection) is an even higher mandate. Accurate, to-scale images of the candidate facilities for D&D could help reduce work risk in many ways. The baseline facility image could be used for engineering studies of all kinds needed for the operation. The image could be used to perform virtual dry runs for dismantlement of large components in the environment of collision models so that the logistics of dismantlement problems could be worked out before actual work. Once the dismantlement process was designed in the model, it could be used for training to maximize readiness before operations begin and minimize exposure during D&D. This would support effort the D&D project s efforts to keep radiological exposure as low as reasonable achievable. LIDAR TECHNOLOGY HAS MANY ADVANTAGES BUT REQUIRES EXPERIENCED PERSONNEL The significant benefits that Industrial LIDAR imaging has for the nuclear industry have already been pursed in the manufacturing, entertainment, architectural, preservation, and

5 defense industries. In evaluating the Cost of Simulators Driven by the Development of Digital Databases (National Defense, November 2000) James Oyler, President and CEO of Evans and Sutherland, a leading supplier of military simulation trainers points out the input challenge to use of simulators. Oyler states, Despite a significant drop in prices of computer chips in recent years, building advanced military simulators remains costly because most of the expense involves development of digital databases. For a number of applications, industrial LIDAR solves this problem cost effectively and the defense department and security agencies show progressively greater reliance on it. While the technology is mature enough for operational applications, it is not deployable as a plug and play operation. Successful use depends greatly on knowledge of proper survey protocol, extensive knowledge of the system variables to set up scanning parameters, integration through a maze of software and hardware links, vision for the multiple outputs and the capability that the software to perform manipulations desired by the use. These systems have no internal reference to standards, and, as such, would be unacceptable for use at nuclear facilities unless calibrated by experienced users. The limits of industrial LIDAR are commensurate with those characteristics of the 3-D imaging, modeling and simulation industry. Industrial LIDAR is a high-tech application that is applied proficiently only in the hands of experienced operators and processors. In reviewing modeling and simulation, the National Academy of Sciences recommended that government funding be increased for education and basic research and development in the simulation and training field. Roger Smith, chief software scientist at BTG in Orlando, FL, states that, Its unsettling that there are only a few universities in the United States that offer graduate programs in simulation and training. If the state of technology in existing application requires specialized resource with advanced training, industrial LIDAR application to DOE s problems will require use (and development) of expert applications personnel. There are firms with specially trained personnel that can assist DOE in applying the technology to DOE s current D&D projects. CONCLUSION LIDAR technology is proven and available. The potential in the DOE and the nuclear industry is just now being recognized. As new application and project results continue, more and more new uses for this cost saving technology will be realized. REFERENCES National Defense Industrial Association (NDIA), November F-22, Joint Strike fighter Trainers Redefine Point and Click Warfare. In Extreme Machines, Jet fighter Simulators that Defy Form, National Defense, November 2000.