Interim Report for the Committee on Long-Term Research Needs for Deactivation and Decommissioning at Department of Energy Sites (2000)

THE NATIONAL ACADEMIES

Advisers to the Nation on Science, Engineering, and Medicine

National Academy of Sciences

National Academy of Engineering

Institute of Medicine

National Research Council

At the request of the Department of Energy’s (DOE’s) Office of Environmental Management, the National Research Council (NRC) empaneled a committee ¹ to assist theDepartment in developing a long-range science plan for deactivation and decommissioning (D&D) research sponsored by the Environmental Management Science Program (EMSP). ² The EMSP requested that the committee write an interim report primarily to provide advice on the technical content of a fiscal year 2001 (FY 01) EMSP call for research proposals ³ and to giveother advice the committee believes would be helpful. Accordingly, the committee directed most of its efforts toward the second item of its task statement: “recommend areas of research where the EM Science Program can make significant contributions to solving [D&D] problems and adding to scientific knowledge generally.” Some general advice, which touches on other portions of the task statement and which will be developed further in the final report, is given in the last section of this interim report. This letter provides the requested interim report, which reflects a consensus of the committee and has been reviewed in accordance with the procedures of the NRC. ⁴

The information used to develop this interim report was obtained from several sources. ⁵ The committee reviewed previous NRC reports relevant to this study (NRC, 1996, 1997, 1998, 1999b). The committee also held four information-gathering meetings to familiarize itself with D&D challenges throughout the DOE complex. ⁶ The first meeting, which was held on March 16-17, 2000 in Washington, D.C., provided the committee with an overview of the Office of Environmental Management’s (EM’s) plans for site cleanup, the EMSP, and the activities of the

• Hanford, May 24-25, 2000, focused on production reactor, separations, and fuel fabrication facilities;

• Oak Ridge, June 26-27, 2000, focused on research reactor, gaseous diffusion, and laboratory facilities; and

• Rocky Flats, August 23-24, 2000, focused on plutonium handling facilities and lessons learned.

The committee has largely completed its fact finding activities and has had significant discussion of findings and recommendations. While further discussions will refine and expand on this interim report, the committee offers the following comments that it believes will be helpful in preparing the FY 01 solicitation and in developing plans for a long-term program.

The committee finds that there are strong safety and economic incentives for innovative D&D technologies that may be achieved through scientific research.

The safety incentive is immediate for workers conducting D&D operations, and it will grow as DOE takes on the more challenging D&D tasks. These workers deal with special hazards that are different from those in other parts of DOE’s Paths to Closure program (USDOE, 1998a), including the following:

• working in confined spaces in areas of high radioactivity,

• disassembling and removing massive steel and concrete structures,

• direct, hands-on manual labor with powerful saws, torches, and lifting devices, and

• incomplete knowledge of the highly complex systems they are dismantling. ⁷

DOE expects to spend some $30 billion for D&D of weapons complex facilities after 2006, compared to about $4 billion until then (Hart, 2000). This is because the biggest D&D challenges, for example at the Savannah River and Hanford sites, will be undertaken after 2006. The DDFA believes that about half of the $30 billion can be saved through use of innovative technologies that it expects could be developed by that time (Hart, 2000).

To meet EMSP’s needs for its upcoming solicitation, the committee has identified, preliminarily, three areas where it feels present technology is inadequate and where it believes EMSP-funded research could make significant contributions. These areas are characterization, decontamination, and remote systems. Within these three areas the committee has five specific recommendations that EMSP may wish to consider in preparing its forthcoming solicitation. Two recommendations deal with characterization, two deal with decontamination, and one deals with the crosscutting area of remote systems (including robotics).

Characterization of contaminated materials is critical at several stages of D&D. Initially, the nature and extent of contamination with both radionuclides and toxic materials must be accurately assessed to ensure adequate protection of workers and the environment, as well as to allow the selection of appropriate methods of decontamination. During decontamination and/or demolition of contaminated equipment and structures, there must be some means of monitoring progress and potential contaminant releases. Finally, after decontamination, the nature and extent of residual contamination must be assessed to determine the final classification and disposal of the item in question.

(1) The committee recommends basic research toward identification and development of means, preferably real-time, ⁸ minimally invasive, and field usable, to locate and quantify difficult to measure contaminants significant to D&D. These means should be applicable to the major materials and configurations of interest, such as concrete, stainless steel, and packaged wastes. The solicitation should identify the contaminants of interest, including tritium, technetium-99, plutonium-239 and other actinides, beryllium, mercury, asbestos, and polychlorinated biphenyls (PCBs). The need for such characterization was recognized in several presentations to the committee during its site visits, but there are no currently funded EMSP D&D projects in this area.

Rationale: The varied nature of D&D facilities has led to a wide range of contaminant types and site-specific characterization challenges, each generally requiring a detector (Janata, 1989; Webster, 1999;) tailored specifically to the contaminant being measured and its matrix. Some 2,700 buildings, constructed mostly of concrete and containing 180,000 metric tons of metals, are currently within EM’s D&D task (Hart, 2000). In its fact finding the committee identified four broad areas where research can advance the state of art: (1) methods to assess the distribution of contaminants within concrete; (2) sensors to measure contaminants on the surface and within micro-cracks of metals; (3) remote sensing of contaminants; and (4) biosensors (see next recommendation).

The development of minimally- and non-invasive real-time in situ sensing technologies to characterize the concentration of contaminants, as a function of depth within concrete, would eliminate difficulties associated with core sample collection and subsequent analysis. Minimally invasive schemes like laser ablation mass spectroscopy (Van Hecke and Karukstis, 1998) or non-intrusive techniques like neutron activation and x-ray analysis appear to be attractive candidates for further research.

More sensitive detectors, ⁹ for example for alpha particles (USDOE, 1999), as well as simple-to-use techniques, such as chemical indicators (Holtz and Asher, 1997), are needed to quickly certify levels of nuclides, hazardous metals, and other toxic substances on structural surfaces and equipment. This will help ensure safety in the workplace and reduce costs—for example by allowing non-hazardous waste to be disposed in landfills. Analysis of residual low-energy beta emitters like tritium and Tc-99 is particularly challenging when these isotopes are

Remote sensing systems can provide both economic and safety benefits by distancing the worker from hazardous work areas. Remote mapping of activity levels using gamma cameras (USDOE, 1998b) is now being used to great advantage in D&D operations. Smaller, higher sensitivity and resolution versions of these instruments would be desirable and may be achievable through further research on detector materials and geometries. Fiber-optic sensing for remote detection of some chemical species is feasible (Lieberman, 1996). Further research could lead to its use in sensing chemical contaminants relevant to D&D. Fiber-optic radiation sensors are a more recent development (Henschel et al., 1992; Huston et al., 1996; Borgermans et al., 2000;), and opportunities exist for both improved performance and novel features such as optical interrogation (Miller et al., 2000).

(2) The committee recommends basic research that could lead to development of biotechnological sensors to detect contaminants of interest. Such research may provide a completely new way to meet the needs for characterization of contaminated materials, which were described in the earlier parts of this section. We believe specific attention to this research opportunity is warranted because the field of biotechnology is rapidly expanding, its potential was not recognized in site presentations heard by the committee, and no biosensor project was funded in the EMSP’s previous D&D research solicitation. The contaminants of interest and the materials and configurations in which they must be detected, noted in (1), should be specified in the EMSP’s request for proposals.

Rationale: Biosensor technology is a relatively young field originating in 1967 (Updike and Hicks, 1967). However, there has been tremendous growth in development and commercialization of a broad range of biosensor devices and applications (Kress-Rogers, 1997). Modern devices can range from fiber-optic (Anderson et al., 2000) and microcantilever-linked immuno assays (Moulin et al., 2000; Thundat et al., 2000) to subcellular and cellular microelectronic systems (Simpson et al., 1998). Analytes measurable by biosensors include a vast array of organic chemicals, biochemicals, inorganics, and metals and more recently ionizing radiation (Lee et al., 2000). Research to integrate microelectronics and nanotechnology (Cunningham, 1998) with elements of gene array technology (Mecklenburg et al., 2000) and cellular engineering may lead to new sensor technology. Bionanosensors are recognized as a key research area in the National Science Foundation’s first call for proposals related to the National Nanotechnology Initiative (see http://www.nano.gov/press.htm for details). Such technology could create new capacity for continuous and remote monitoring in chemically and physically complex environmental and structural systems characteristic of DOE’s site D&D needs.

Like characterization, decontamination of equipment and facilities is necessary at several stages of the D&D process. Initially, radiation and contamination levels may have to be reduced to allow worker access or to limit their exposure to radiation and other hazards. Decontamination may be required before dismantling or demolition work to prevent the spread of radioactive or toxic materials. Unplanned releases can have off-site as well as on-site consequences. Decontamination procedures are intended to result in a small volume of the most hazardous

waste, and much larger volumes of waste that has low or no hazard, thus reducing the cost and long-term risk of disposal. Some decontaminated equipment or facilities might be recycled or reused. The end state of any decontamination activity must be consistent with both site-specific and overall DOE cleanup objectives.

(3) The committee recommends basic research toward fundamental understanding of the interactions of important contaminants with the primary materials of interest in D&D projects, including concrete, stainless steel, paints, and “strippable” coatings.

Rationale: Scientific understanding of the interactions among contaminants and construction materials is fundamental to developing more effective D&D technologies. Both radioactive and toxic contaminants can exist in a variety of chemical forms (for example, in different valence states, complexes, or as colloids), which exhibit very different behaviors. While a good deal of chemical data on the contaminants themselves exist (Delany and Lundeen, 1990), as well as data on their transport in the environment (van der Lee et al., 1997), there is little information of direct relevance to D&D problems. Such information includes how contaminants bind to steel and concrete surfaces, how they penetrate into these materials, their migration into pores, fissures, and welds, and time-dependent “aging” effects (Dzombak and Morel, 1990). Once sufficient thermodynamic and kinetic data on these interactions are obtained to allow their modeling from first principles, the models would allow various decontamination approaches to be evaluated and provide a better way to interpret data from characterization.

(4) The committee recommends basic research on biotechnological means to remove or remediate contaminants of interest from surfaces and within porous materials.

Rationale: The capacity of microbiological processes to destroy, transform, mobilize, and sequester toxins, pollutants, and contaminants is well-established (Young and Cerniglia, 1995). Through research to extend well-known technology in mineral ore leaching and metal recovery (Torma, 1988; Ehrlich and Brierley, 1990), these biochemical capacities may be exploitable for removal of metals and radionuclides from concrete and building debris. An excellent example of which was recently described in an American Society for Microbiology report (see ASM News. 66:133). In addition, microbial biocorrosion processes for structural metals and concrete are well established and the opportunity exists to investigate fundamental processes that could facilitate volumetric reduction of waste from D&D activities. Biotechnical advances in surface treatments of contaminated structures and materials are anticipated from continuing R&D activities, elucidation of biocatalytic properties of biological systems and engineering chemicals, and biosurfactants with unique physical chemical properties (Sullivan, 1998; Banat et al., 2000). A fundamental understanding of the biological processes would also help to ensure that waste by-products from the decontamination could be safely treated and stabilized.

For D&D work, remote systems provide a unique means to separate workers from hazardous work areas, thus enhancing their safety and productivity. This technology crosscuts all of the other D&D areas—characterization, decontamination, and dismantlement—and has the potential for substantial performance enhancement and cost reduction. The committee recognizes

the broad range of potential applicability of fundamental advances in this area (Benhabib and Dai, 1991; Andary and Spidaliere, 1993; Gombert et al., 1994; Chen and Burdick, 1995; Paredis and Khosla, 1996; Kapoor and Tesar, 1998; and Tesar, 2000) and makes the following recommendation:

(5) The committee recommends basic research toward creating intelligent remote systems that can adapt to a variety of tasks and be readily assembled from standardized modules. Today’s remote systems are one-of-a-kind devices of high cost and limited capability. Their inflexibility leads to rapid obsolescence and is a barrier to their deployment. The recommended initial research focus would be as follows:

Rationale: The actuator is the power (muscle) of remote systems, and as such it is the key to performance, reliability, and cost. Except for better construction materials and improved control electronics, most actuator technology has not changed for several decades. Today’s actuators typically use only one sensor (for position) so that virtually no real time data (for example, force and velocity) are available to make them “intelligent.” More complete sensory input, coupled with decision making software (see below), can produce intelligent actuators that are able to adapt to a variety of tasks. Achieving a relatively inexpensive modular design to allow “plug and play” deployment of these devices would be especially useful in DOE D&D projects because equipment that fails or becomes contaminated is usually discarded. Research to answer the question of granularity (What is the minimum number of required standard modules?) to enable the assembly on demand of the maximum number of remote systems would make the overall system substantially more cost effective in deployment and maintenance.

Rationale: Criteria-based decision making is the essence of intelligence in robotic systems. It is identical in concept (Miller and Lennox, 1991; Sturzenbecker, 1991; Stewart et al., 1992) to the operating systems in personal computers: What is the best use of the system’s resources to perform the task at hand? Today’s control of robotic devices is derived from techniques developed during World War II in which control is linear (based only on the difference between two measured parameters). A robot capable of mimicking human adaptability, however, would require a non-linear control system coupled to many parameters corresponding to the physical features that accurately represent performance of the task. The criteria-based software could be universal in the same sense that operating systems on personal computers are universal—one system supports many different applications.

Rationale: In the initial planning and characterization phases of D&D work, workers often must enter an area of high radiation and contamination that is also congested with left-in-place equipment and materials for which removal inevitably involves physical stress (fatigue) and the potential for personal injury (Fournier et al., 1998). Virtual reality systems could allow workers to perform essential survey and decision making functions from a remote location (Lloyd et al., 1999), thus enhancing their safety and productivity. Advances in the state of the art

as now used in deep sea exploration should be pursued to improve overall system performance by providing force feedback, remote vision, collision avoidance, and radiation resistant sensor technology.

The committee appreciates the quality and openness of presentations it received during its fact finding. This information led the committee to recognize several areas in which it believes advice at this time will be useful to EMSP in its overall strategic planning. The advice summarized below is preliminary, and the committee intends to develop it further in its final report. We note that similar advice has been provided in previous NRC reports and in the Strategic Laboratory Council’s recent Adequacy Analysis of the Environmental Quality R&D Portfolio (USDOE, 2000).

(1) The EMSP was initiated by the 104^th Congress “...to stimulate the required basic research, development and demonstration efforts to seek new and innovative cleanup methods to replace current conventional approaches which are often costly and ineffective.” ¹⁰ The committee agrees with the recommendation of earlier NRC reports that EMSP should emphasize basic research (NRC 1997; NRC 1999b). The committee’s impression is that most of the EMSP’s current efforts are aimed at short term, site-specific D&D problems. Developing new technologies to address current site needs is the responsibility of the DDFA, not the EMSP. While relevance ¹¹ to site-specific problems is important, too narrow a focus may preclude funding valuable “outside the box” research ideas. The NRC Committee on Decision Making made a similar recommendation for some exploratory research to meet the need for backups and alternatives to baseline flowsheets (NRC, 1999c).

(2) To help guide future R&D efforts, the committee believes that DOE-OST should develop a more comprehensive, coordinated, and specific definition of complex-wide D&D needs that could provide a basis for assessing areas in which basic research could contribute. This should include all facilities that EM will eventually D&D under its cleanup mission, whether or not they have been declared as D&D projects. It should identify the major, complex-wide challenges that could give the greatest return on investments in new technologies.

In its final report the committee will provide its own view of DOE’s significant D&D problems that cannot be addressed effectively with current technologies, according to its statement of task. Its views will be at an overarching level, based on its one-day fact finding visits to Hanford, Oak Ridge, and Rocky Flats and its review of existing needs lists. The general advice given here and in the next item is intended to help DOE develop a sustainable process for identifying in detail its D&D research needs.

Much of the post-2006 cost savings from new technologies projected by the DDFA is for facilities that have not yet been released to EM (Hart, 2000). The committee saw a variety of lists

of needs, but they were too narrow, short term, or general to help focus on where basic research could be useful. Developing a complete, useful definition of the D&D challenges will require significant effort from the many DOE facility “owners,” but it is essential to developing an effective research and development (R&D) plan. ¹² The efforts should start now to help prepare for proposal calls for FY 02 and thereafter.

(3) OST has made an effort to obtain meaningful input from the sites on R&D needs through establishment of the Site Technology Coordinating Groups (STCGs). The committee believes that the DOE contractors and STCGs could contribute more toward identifying true R&D opportunities if they were encouraged by their management to identify major long-term challenges rather than lists of specific technology development needs.

Moreover, there may be value in using an additional, different approach in which members of the scientific community are engaged on a broader sustained basis in understanding the D&D challenges and defining the underlying scientific information that is needed to develop solutions. The new technology or basic research which would effectively address these challenges may be identified more readily by the external scientific/technical community and national laboratories, than by the site operating contractors. Previous NRC reports have recommended greater outreach to universities, national laboratories, and the foreign sector (NRC 1998; NRC, 1999b; NRC, 1999c). The committee will make suggestions for implementing this additional approach in its final report.

(4) The committee believes that EMSP should have a strong role in developing a sound scientific basis for setting standards for the end states ¹³ of D&D and for release of buildings and materials. The committee also believes this is an appropriate subject for EMSP’s R&D program. DOE has no general risk assessment basis for D&D end states. End states for facility D&D are currently, in most cases, being determined on an individual basis, with input on end use from local stakeholders. ¹⁴ It is not suggested that this decision process change, but rather that science-based standards be available to the decision makers.

End states for free release of recycle materials are a matter of continuing controversy. The U.S. Nuclear Regulatory Commission has recently asked the NRC for advice on this complex issue. ¹⁵ For D&D projects, the end state determines the cost, schedule, and the technology to be used—or even if an adequate technology exists. The importance of establishing end states was noted by the previous NRC committee on D&D technologies (NRC, 1998), and more broadly by other NRC committees ¹⁶ and international groups (NEA, 1999; and MacLachlan, 2000).

(5) The committee believes that EMSP should consider further encouraging interdisciplinary collaborations, among disciplines such as biology, physics, materials science, and engineering in its calls for proposals. ¹⁷ Due to the nature of D&D work, interdisciplinary collaborations are more likely to lead to new, deployable technologies than research in a single area. One early step could be to provide for discussion amongst the proposers of the potential projects selected from review of the FY 01 pre-proposals, perhaps in the context of an EMSP National Workshop such as that held in April 2000.

The committee appreciates this opportunity to make input to the EMSP by this interim report. The final report, which the committee expects to complete in the spring of 2001, will provide more detail and discussion on the recommendations and preliminary general advice presented here.

Attachment A: Committee Roster

Attachment B: Statement of Task

Attachment C: List of Reviewers

Attachment D: References