The key issues noted here are some of those raised by individual workshop participants, and do not in any way indicate consensus of workshop participants overall.
• Civilian nuclear material is found in many countries around the world, although exact quantities are not known.
• Even countries that do not have fissile materials may be used as transit countries for illicit transport of nuclear materials.
• Finding a balance between public concerns about nuclear energy and the need for greater electrical capacity is extremely difficult at present. These challenges increased sharply after the situation with the Fukushima Daiichi nuclear plant following the tsunami on March 11, 2011.
• Planning for the expansion of nuclear power in India as a part of the larger energy picture to support economic growth more broadly in the context of a growing population, much of which is rural, is very challenging.
• In the long term, India is working to develop proliferation-resistant fuel cycles.
• Public acceptance of the use of nuclear materials for nuclear power is based on experts’ assurances that nuclear materials will remain under control and appropriate use, and that the public will not be harmed either by a safety incident or a security incident.
• Using technologies and techniques for material control and accounting to balance and complement nuclear security is how operators maintain
as much control over the nuclear material as possible, while still being able to use it for its intended purposes.
Promising Topics for Collaboration Arising from the Presentations and Discussions
These promising topics for collaboration arising from the presentations and discussions are not those representing the consensus of the participants, but are rather a selection of those topics offered by individual participants throughout the presentations and discussions.
• There is a high degree of uncertainty about accounting for materials in nuclear waste. Despite efforts to reduce the amount of plutonium or uranium that goes into waste, one cannot eliminate it entirely. This is an area in which cooperation has a great deal of potential.
• Measurement control, including questions such as how uncertainties combine, and which measurement methods are particularly problematic, are areas for joint collaboration.
• Indian and U.S. experts could work on nondestructive analysis to develop additional ways or techniques to help further establish how measurement standards are defined and characterized and the pedigree of material or accuracy of measurements.
The U.S. government has made safeguarding weapons-grade plutonium and highly enriched uranium an international policy priority, and convened The 2010 Nuclear Security Summit in Washington, D.C., on April 12 and 13, 2010. Forty-six governments sent delegations to the summit and twenty-nine of them made national commitments to support nuclear security. During the Summit, India announced its commitment to establish a Global Centre for Nuclear Energy Partnership. The Centre is to be open to international participation through academic exchanges, training, and research and development efforts.
The Centre is “aimed at strengthening India’s cooperation with the international community in the areas of advanced nuclear energy systems, nuclear security, radiological safety and radiation technology applications in areas such as health, food and industry”.1 In November 2010, the United States and India signed a memorandum of understanding that provides a general framework for cooperative activities in working with India’s Centre. According to the White House, “In working with India’s Centre, the United States intends to give priority to discussion of best practices on the security of nuclear material and facilities, develop-
1 Government of India. Ministry of Science and Technology. 13 August 2010. “Global Centre for Nuclear Energy Partnership.” Available at: http://pib.nic.in/newsite/erelease.aspx?relid=64718. Accessed September 20, 2013.
ment of international nuclear security training curricula and programs, conduct outreach with nuclear industry, and cooperation on other nuclear security activities as mutually determined”.2
As India builds its Centre, and as the United States endeavors to fulfill its commitment to assist in the development of the Centre, the U.S. National Academy of Sciences (NAS), together with its partner of 15 years, the National Institute for Advanced Studies (NIAS) in Bangalore, India, organized a joint Indian-U.S. workshop entitled, “India-U.S. Cooperation on Global Security: A Workshop on Technical Aspects of Civilian Nuclear Materials Security,” held October 29-31, 2012 on the NIAS campus in Bangalore, India. The aims of the workshop were to identify and examine potential areas for substantive scientific and technical cooperation between the two countries on issues related to nuclear material security, to establish scientist-to-scientist contacts between experts in nuclear materials management in the United States and counterparts in India, and to build confidence in cooperation on nuclear security issues. The hope is that if the technical community identifies concrete, technically-based areas for potential future collaboration, these could be the foundation for progress at the Centre and between the two countries more broadly.
Workshop participants, technical experts in a variety of fields associated with civilian nuclear materials security, provided presentations and engaged in frank discussions. These experts were chosen by the workshop organizers from their countries’ national laboratories, academia, and non-governmental organizations. Over the course of the three-day workshop they provided their knowledge and experience and shared ideas for possible future joint collaborations in this area between India and the United States. The concluding session of the workshop identified initial areas of possible cooperation that had emerged through the presentations and discussions. This report provides a factual summary of the workshop presentations and discussions. There was no attempt to reach consensus findings and recommendations.
CIVILIAN NUCLEAR MATERIALS: OVERVIEW
R. Rajaraman provided workshop participants with an overview and introduction to nuclear materials. He began by stating that until recently, “nuclear materials” were frequently understood to be synonymous with the term “fissile materials.” Fissile materials are directly weapon-usable, and therefore considered the most dangerous. Today, however, he explained, “nuclear materials” are often defined more broadly and include radiological materials: “just plain natural uranium ore, industrial uranium or depleted uranium, plutonium isotopes
2 U.S. Government. The White House Office of the Press Secretary. 8 November 2010. “Fact Sheet on U.S.-India Nuclear Security Partnership.” Available at: http://www.whitehouse.gov/sites/default/files/india-factsheets/Fact_Sheet_on_Nuclear_Security.pdf. Accessed September 20, 2013.
produced in reactors, spent fuel from reactors, all radioactive substances, fissile or not.” Fissile materials, the nuclear materials of focus in this workshop, are those that undergo nuclear fission easily without adding energy. Specifically, these materials are uranium-235, uranium-233, and different isotopes of plutonium. Other materials, such as americium and neptunium, are technically fissile, but are not typically used in significant quantities in the civilian nuclear power cycle.
Rajaraman explained that natural uranium contains less than 1 percent of uranium 235. “The bulk of natural uranium, such as uranium-238, cannot sustain fission. But even that tiny fraction of less than 1 percent is sufficient to fuel heavy water-moderated reactors, like our reactors in India.” Plutonium is not found in nature. It is a by-product of nuclear reactions in the fuel rods of nuclear reactors. In India, plutonium is separated from the fuel rods in reprocessing units. There is not sufficient fissile material in spent fuel to sustain a fission chain reaction unless the plutonium is separated and concentrated in new fuel.
Civilian nuclear material is found in many countries around the world, although exact quantities are not known. According to the Fissile Materials Group, Russia and the United States have the largest quantities of nuclear materials in the world. It is estimated that in total there are about 1400 tons of highly-enriched uranium (HEU) in the world and about 495 tons of separated plutonium.3 The current worldwide stocks of fissile material together can fuel 170,000 nuclear warheads. While much of this material exists in the military sector, a significant quantity is in the civilian sector which underscores the importance of continuously securing this material.4
Rajaraman presented the distribution of civilian HEU around the world. The non-nuclear weapons states (as defined by the Treaty on the Non-Proliferation of Nuclear Weapons [NPT]) have about 10 tons of HEU, or sufficient fuel for approximately 400 warheads. Rajaraman noted that even countries that do not have fissile material may be used as transit countries for illicit transport of nuclear material. Therefore, he noted, responsibility for securing fissile materials cannot be limited to countries with nuclear weapons, but rather it must be a truly cooperative international effort.
Rajaraman believes that the nuclear summits are an example of international cooperation on nuclear materials security. From an Indian perspective, one of the reasons for the success of the nuclear security summits—the initial summit in Washington and the second summit in Seoul, Korea in 2011—was that the highest level of Indian leadership was invited to participate, setting them on equal footing with nuclear weapons states. During the Washington summit, India, Japan, China, and Italy announced the creation of new centers of nuclear security technologies and training. The summit process, and the commitments of participating countries,
4 Ibid, p. 11 and p. 29.
emphasize that nuclear terrorism continues to be one of the most challenging threats to international security.
BALANCING ENERGY NEEDS AND NUCLEAR MATERIALS SECURITY
Public Concerns about Nuclear Energy and Development Efforts
M. R. Srinivasan, former chairman, Atomic Energy Commission (AEC) of India, provided remarks that outlined the current challenges faced by those in India who are attempting to provide increased electrical capacity for the development of the country. As he explained, finding a balance between public concerns about nuclear energy and the need for greater electrical capacity is extremely difficult at present. These challenges increased sharply immediately after the situation with the Fukushima Daiichi nuclear plant following the tsunami on March 11, 2011. In response to these events in Japan, the local population living near the Kudankulam nuclear power plant in the southern Indian state of Tamil Nadu protested by the thousands to prevent the loading of reactor fuel. These protests continued for months and involved the local villagers and those involved in fishing who protested from the water. While the protests reached their height toward the middle of 2012, opposition continues.
Srinivasan explained that he was responsible for speaking at a large number of public meetings (40-50) in many parts of India, participating in many discussion groups and television and newspaper interviews, to try to bring some kind of balance to the debate. Local politics also played a role in the local response to the nuclear plant as two leading regional political parties reversed majority and minority positions in elections. The new government attempted to meet with the public to understand their concerns and to attempt to explain the scientific and technical evidence behind the safety and security of the plant. The government established a 15 member committee, which was headed by a well-known space scientist who later studied oceanography and became an expert on tsunamis and earthquakes. That committee listened to all of the protesters’ concerns, and the protesters had their own scientific advisors that raised several questions, all of which were answered by the committee.
The opposition was led by a group called the People’s Movement Against Nuclear Energy. Srinivasan stated that unfortunately they were not concerned with the safety of the Kudankulam plant. Rather, their objective was to have no nuclear energy at all. So they just sat across the table and listened to voluminous explanations about the plant’s safety features and said, “no we don’t want to look into all of these things. We don’t want this power plant to be started. It is as simple as that.”
Srinivasan was then asked by the Chief Minister of Tamil Nadu to chair another committee to review the work of the first committee established by the Government of India. The goal was again to examine the concerns of the people and talk to them and find a resolution to the stalemate. Srinivasan and his
colleagues also went through the safety features and focused on those related to the geological, seismological, and tusunami-related issues, which were the greatest concerns of the people. There were no scientific or technical reasons to stop the project because the safety issues were addressed by an advanced, third-generationplus reactor design, and by the fact that the site does not have seismic or tsunami activity as had Fukushima. The committee also explained that there was an additional special feature of the Kudankulam reactor, the passive safety system, incorporated into the design to ensure that the reactor fuel would continue to be cooled even in the event of a loss of power to the reactor. At the request of the Indian safety authorities, this special design feature was incorporated to dissipate the residual heat to air through a set of very large radiators, located outside the reactor building. Again, a protestor said, “no, we are not interested in all of these explanations,” Srinivasan said. Regardless of these objections, the first fuel was loaded into the reactor vessel and power generation was to begin in December 2012.
This situation not only illustrates the difficulties in communicating safety issues surrounding nuclear power, it also illustrates real security concerns. Srinivasan stated that during the protest, a population of about one or two thousand protestors virtually held seige to the plant. They blockaded entry to the power plant and personnel could not enter. They said, “no, we don’t want these large workforces to come in because we want this work to be suspended.” They only wanted to let about 20 or 30 people in to maintain the essential services such as water purity, temperature control, and the like. As work resumed, Srinivasan advised the deployment of significant security forces to ensure safety and security. On one occasion, approximately 400 fishing boats approached by water and people attempted to enter the plant’s premises.5
He noted that a lot has been learned, but there is still a lot more that can be learned regarding how to address such situations. These lessons may be relevant to other situations as well because India is experiencing a great deal of opposition to many projects, including mining projects, hydraulic projects, coal-fired power station projects, nuclear projects, steel plants, and others. This presents a significant challenge as the energy needs of the country that reached a new peak in the last 18 months due to a combination of factors.
The last monsoon brought less rain causing hydroelectric stations to reduce the amount of power they could generate. Coal stocks at 47 coal-fired power stations are at a critically low level, reducing power generation by 65,000 megawatts of generation capacity. Gas-fired plants are also reducing capacity due to a lack of Indian gas supplies. The predicted increase in capacity of gas supplies
5 Fishermen lay siege to Kudankulam nuclear plant, Rediff.com News, 08 October 2012. Available at http://www.rediff.com/news/slide-show/slide-show-1-fishermen-lay-siege-to-kudankulam-nuclear-plant/20121008.htm#1.
by 50 percent from off-shore fields in the eastern part of India did not occur.6 In combination, the lack of hydroelectric power as well as coal and gas electrical sources has reached a critical point. At the same time, protests continue against these power-generation sources and the news media reports on the protests. Srinivasan noted that few people in industry, business, or academia enter this debate and the media does not receive balanced information. This situation presents a challenge because to sustain economic growth rates of eight or nine percent, more energy is needed. This raises a sociological issue as well challenges associated with the distribution of gains from development.
Since the debates between 2005 and 2008 about the ability of India to purchase uranium on the international market, in which Srinivasan participated as a member of the AEC, he notes that India has been able to purchase natrual uranium and low-enriched uranium from Russia, Kazakhstan, and other countries. This has allowed Indian reactors to run at about 80 percent capacity or higher. That said, although the Indian nuclear power program dates back to the 1950s, it only generates 5,000 megawatts of nuclear electricity from 20 reactors, not including the two large reactors of Russian design in Kudankulam. Of these 20, 16 were designed and built in India. India also has small reactors, mostly 220 megawatts and two of them are 540 megawatts, and work has begun on a number of 700-megawatt units of domestic design, four of which are under construction and a total of at least 12 are anticipated.7
Srinivasan concluded by reiterating that India is interested in developing its nuclear industry and producing significantly greater quantities of nuclear-generated electricity, and to do this, India will need to cooperate with international partners, in addition to addressing continuing domestic concerns of safety and security.
Planning for Nuclear Energy Expansion while Maintaining Security
Ravi Grover noted the challenges of planning for the expansion of nuclear power to support economic growth and an increasing population, much of which is rural. He began by stating that India has seen impressive economic growth for close to two decades despite several challenges, one of which is the ability of existing and expanding infrastructure to support that growth. “Energy is the most important part of that infrastructure, and it has been a major challenge for the Department of Atomic Energy (DAE) to ensure that adequate ener-
6 The projected demand for 2011-12 was 89 BCM (Ref: Appra Zaifrani and Karthik Madhavan, The Gas Sector MBA Thesis, p. 15 available at http://www.slideshare.net/kadweiser/natural-gas-in-india). The actual production was 47.559 BCM (Ref: Government of India, Ministry of Petroleum and Natural Gas, Indian Petroleum and Natural Gas Statistics 2011-12, p. 3, available at http://petroleum.nic.in/pngstat.pdf.
7 Nuclear Power Corporation of India website-Plants under operation. Available at http://www.npcil.nic.in/main/AllProjectOperationDisplay.aspx.
gy is available. Providing energy reliably at affordable prices will continue to be a challenge, as India is not rich in energy resources.”
According to the 2011 census, India’s population is 1.2 billion, and 69 percent of the population lives in rural areas.8 In spite of impressive growth in installed electrical capacity and the fact that globally India ranks fifth in terms of total electricity generation, India’s per-capita electricity consumption is well below the world average. Half of rural households have no access to electricity and most of them use biomass energy.9
Grover relayed that DAE studied the growth of energy demand with the objective of quantifying the share of nuclear energy needed in the electricity mix in the coming five decades in India. DAE experts looked at the fuel resource position, including the potential for renewable energy sources, projected population growth, projected economic growth, and likely improvements in energy efficiency of the economy. From this they determined estimates for scenarios of growth of electricity generation in the country for the next 50 years, taking 2002-2003, which was the first year of the tenth five-year plan, as the base year. As an indicator of economic growth, DAE used a study by Goldman Sachs, which had just been published at that time.10 For population growth, they used various forecasts available in India and hypothesized that the population will reach 1.5 billion by the middle of the 21st century.11 DAE’s study indicated that total electricity generation in the year 2052 will be almost 8,000 terawatt hours, corresponding to annual per-capita generation of 5,300 kilowatt hours. Installed capacity in the year 2052 was estimated to be close to 1,400 gigawatts.12
The question is, Grover stated, “Is the per-capita generation of 5,300 kilowatt hours too high for India?” There is a school of thought that says that a tropical country like India does not require heating, and therefore energy demand in India will always be less than what it is in the West where the climate is temperate. However, when one observes what is happening in India’s immediate neighborhood, a different picture emerges. The per-capita energy demand in Singapore is the same as the average of Organisation for Economic Co-operation and Development countries, and the energy demand in Malaysia and Thailand is also growing.13 One should not expect a different scenario in India. Grover further noted that
8 Census of India, Government of India. Available at http://censusindia.gov.in/2011-prov-results/data_files/india/Final_PPT_2011_chapter3.pdf.
9 Central Electricity Authority Government of India. Available at http://www.cea.nic.in/reports/yearly/lgbr_report.pdf.
10 Goldman Sachs (2003), Dreaming With BRICs: The Path to 2050, Global Economics Paper No: 99. Available at http://www.goldmansachs.com/our-thinking/archive/archive-pdfs/brics-dream.pdf.
11 Ibid, p. 8-10.
12 R. B. Grover and Subhash Chandra, “A Strategy for Growth of Electrical Energy in India,” Document No.10, Department of Atomic Energy, Mumbai, August 2004.
13 IEA (2012) Key World Energy Statistics. Available at http://www.iea.org/publications/freepublications/publication/kwes.pdf.
the Planning Commission of India, in its report on integrated energy policy, forecasted a growth rate higher than that of the DAE study.14 To put the numbers in perspective, the total energy generation by utilities and power plants combined in the previous fiscal year, which ended on 21st March 2012, was about 1,000 terawatt hours, or about one-eighth of what Grover noted as projected by the middle of the century. He noted the projected growth as a very large, but achievable task.15
For supply options, one has to look at the fuel resources of India, which include coal deposits, but its oil and gas reserves are quite modest. With the ever-increasing demand for coal for thermal power plants, one can safely say that the coal supply will not last for more than a few decades. Mining and transportation also present problems for the use of coal. Renewable energy sources are also a possibility, but may be insufficient.
Grover then cited a recent report by S. P. Sukhatme, former director of Indian Institute of Technology Bombay and former chairman of the Atomic Energy Regulatory Board (AERB). Sukhatme estimated the full potential of all renewable energy sources (solar thermal, solar photovoltaic, large and small hydropower, wind power on land as well as offshore, biomass, and tidal power) at 1,229 terawatt hours annually.16 This is a very optimistic estimate, he said, but even this is nowhere near the projected annual demand of 8,000 terawatt hours that India would need by the middle of the century.17 Nuclear energy seems to be the only possible option. A Planning Commission-initiated report on integrated energy policy has referred to nuclear energy as the most viable means of achieving long-term energy security. It calls for pursuit of a closed fuel cycle to enable India to tap into vast thorium resources, and become truly energy independent beyond 2050.18
Security of nuclear materials is built into the day-to-day operations of India’s nuclear program. Grover defined the open fuel cycle as one which “disposes of spent fuel without extracting plutonium.” He stated, “such a disposal would result in the creation of a plutonium mine for posterity,” where “the security risk is aggravated if such a disposal is designed to be retrievable.” To ensure that there is no buildup of the plutonium stockpile, India is strictly observing the principle of “reprocess to reuse.” In India, he noted, the reprocessing of spent fuel and fast
14 Planning Commission (2005), Draft Report of the Expert Committee on Integrated Energy Policy. Available at http://planningcommission.nic.in/reports/genrep/intengpol.pdf.
15 Planning Commission (2012), Power and Energy, P, 342. Available at http://planningcommission.nic.in/plans/planrel/fiveyr/11th/11_v3/11th_vol3.pdf.
16 S. P. Sukhatme (2012) Can India’s future needs of electricity be met by renewable energy sources? A revised assessment, Current Science, Vol. 103, No. 10, 25 November, available at http://www.currentscience.ac.in/Volumes/103/10/1153.pdf.
17 R. B. Grover and Subhash Chandra, “A Strategy for Growth of Electrical Energy in India,” Document No.10, Department of Atomic Energy, Mumbai, August 2004.
18 Planning Commission (2005), Draft Report of the Expert Committee on Integrated Energy Policy, available at http://planningcommission.nic.in/reports/genrep/intengpol.pdf.
reactor waste are being synchronized to preclude the buildup of a plutonium stockpile. Technologies for the vitrification of high-level waste from reprocessing have been developed, and vitrified waste, after it has been packed in stainless steel containers, is being stored in a solid waste civilian storage facility.
In addition, Grover noted, India has given equal emphasis to developing a sound framework for governance of nuclear power, and the Atomic Energy Act of 1962 is the main legislation in India.19 The Act governs radiation protection, safe disposal of radioactive waste, the operation of mines and minerals, the handling of specified substances, and the irradiation of food and the like. Other legislation related to governance of nuclear power are the Mines and Minerals Act of 1957, the Weapons of Mass Destruction Act of 2005, and the recently-enacted Civil Liability for Nuclear Damage Act.20
Grover clarified that while India follows a nomenclature for nuclear and dual-use items that is different from that followed by the Nuclear Suppliers Group, the end objective is the same. More recently, the Government of India issued guidelines for implementation of arrangements for cooperation concerning peaceful uses of atomic energy with other countries. The AERB, the regulatory board in India, was established in 1983 to convert the regulatory body’s de facto independence to de jure independence. The Nuclear Safety Regulatory Authority Bill 2011 was introduced in the Parliament and has already been examined by the relevant parliamentary standing committee.21 The government is working on amendments to the bill in light of recommendations from the standing committee.
In addition to national legislation, India has taken additional obligations under various international mechanisms. Of particular importance for this workshop is the Convention on the Physical Protection of Nuclear Material and its 2005 amendment, the Convention on Nuclear Safety.22 India also participates in the nuclear security summit process. For both the Washington summit and the Seoul summit, the Indian delegation was led by the prime minister, the highest diplomatic and political position in the country. At the Seoul summit, the prime minister announced a voluntary contribution to the nuclear security efforts of the International Atomic Energy Agency (IAEA). India also hosted a Sherpas meeting in preparation for the Seoul summit. Further, at the end of November 2012, India will host a workshop in cooperation with the United Nations 1540 Commission. India has also shut down its research reactor operating on highly-
22 IAEA, The Convention on Nuclear Safety. Available at http://www-ns.iaea.org/conventions/nuclear-safety.asp.
enriched uranium. Overall, India is trying to pursue those technologies which help minimize the problem of security of nuclear materials.
India is not resting on its laurels, he said, but is continuously trying to work further to improve nuclear security. One significant step was announced by the prime minister at the 2010 Washington summit: the establishment of the Global Centre for Nuclear Energy Partnership. The Global Centre will become an important platform for India to interact with the world community in all aspects of peaceful uses of nuclear energy, including nuclear security, safety, and nonproliferation. Extensive facilities will be set up at this center for training nuclear security professionals.
Further, to gain international experience, DAE has invited an Operational Safety Review Team from IAEA to look at two reactors in Rajasthan. Earlier, all plans of the Nuclear Power Corporation of India Limited were peer-reviewed by the World Association of Nuclear Operators. The government has also announced that a mission from IAEA will be invited for the regulatory review, which could occur next year.
Grover stated that thus far his remarks addressed the security of nuclear materials in the short and medium term. In the longer term, he said, India is working to develop proliferation-resistant fuel cycles. This effort includes developing technologies for reprocessing so that plutonium is separated along with uranium, and developing thorium-based reactor systems. The overall objective is to use nuclear science to reduce the requirement of security of nuclear materials.
In summary, India is developing a closed fuel cycle, with technologies consistent with this approach. Reprocessing is therefore pursued to reuse recovered plutonium. Further, adequate steps, including the establishment of training facilities, are being taken to secure the future. To address the issue of security of nuclear material over the longer term, research and development of proliferation-resistant technologies has been ongoing for the past several years. Grover reiterated that one should aim to use nuclear science to reduce the requirement of security of nuclear materials and address the residual requirement using standards and procedures that have been developed for this purpose.
Nuclear Material Measurements:
Protecting the Public and Increasing Confidence in Safety and Security
Peter Santi of Los Alamos National Laboratory focused his remarks on nuclear material measurements and their role in not only nuclear security, but also in nuclear safety, material control and accountability, and, to some degree, in nuclear safeguards. The primary goal of all of these efforts is how to ensure that the public is not harmed by nuclear materials. Public acceptance—or potentially, new acceptance—of the use nuclear materials for nuclear power is based on experts’ assurances that nuclear materials will remain under control and appropriate use, and that the public will not be harmed either by a safety incident or a security incident. This requires the establishment of three important princi-
ples as ssociated with managing nuc clear material w within a nucle ear facility (thr ree S’s):
• Safety: ensuring that material does not cause harm to the public or workers through an accident or through improper configurations
• Security: preventing material from leaving an authorized area or from being used improperly
• Safeguards: ensuring that material is accounted for and under constant control in the facility
With respect to safeguards, Santi rephrased this as “I know where all my material is. I know where it is going. I know what it is being used for or where it is being stored and how it’s being stored. I know it is going to be leaving the facility to go to the next place, whether it be going to a fuel fabrication facility, to the nuclear reactor to be used, or to a nuclear waste facility that is an appropriate repository.”
While these three principles or objectives have different responsibilities associated with managing nuclear material, one area of commonality among them is the need to be able to detect nuclear material, identify it, and quantify how much is there. This relies on nuclear material measurements. Nuclear material measurements assist the entire nuclear industry in being able to help manage its materials.
Santi then presented a schematic idea of what a generic LEU fuel fabrication facility would look like (see Figure 1-1). Such a facility converts uraniumusually UF623 gas into fuel pellets-that can be used in fuel assemblies that are loaded into a nuclear reactor.
FIGURE 1-1 Generic LEU Fuel Fabrication Facility. SOURCE: Santi,20l2.
23 UF6 is uranium hexafluoride, the chemical form of uranium used in the enrichment process.
In the far left corner of Figure 1-1 there is a UF6 cylinder storage area. Before accepting material at a facility, one has to ask the question, “How do I know the material has not been tampered with or somehow disturbed during the transportation process?” Changes create what is known as shipper-receiver difference. A measurement is needed when items are received to ensure that the facility sent the intended materials and that the items received are those that the shipper sent. Measurements may be as simple as weighing the cylinders or simply counting how many cylinders were received.
Depending on the value of the material and how much of a threat that material may cause to the public, one additional step may be needed, such as measuring a property associated with the UF6 to ensure that the material received has the same properties as those requested (e.g., if the shipper said it sent 4 percent enriched U-235 in those cylinders, measurements may be needed to confirm that 4 percent enriched U-235 was received). In this case, a gamma-ray measurement may be taken using a gamma-ray detector next to the cylinder wall. This increases confidence in the ability to move material between facilities. To account for all the material within the facility, one must account for how much came into the facility by either relying on shipping records or on individual measurements on behalf of the facility manager. All materials measurements have some inherent uncertainties, depending upon the measurement technique used. Accounting for these uncertainties must be propagated throughout the entire material accountancy and management chain. Further, depending on how often accountancy is done at a facility, these cylinders may be measured again at some point.
In the scenario represented in Figure 1-1, the material has come to the facility to make fuel for nuclear reactors, and it will eventually be moved to another place in the facility where the UF6 gas will be converted into uranium oxide power, UO2. That process involves chemistry and there will be some losses within the pipes and other equipment associated with that conversion process. There will also be some scrap and other materials that go to scrap recovery and waste output. Some of that uranium will be accounted for as part of the material accountancy process. The vast majority of the material will be utilized in Part C of the schematic (Figure 1-1), fuel fabrication. The uranium oxide powder in various cans will be sintered and turned into fuel pellets, which are loaded into fuel rods that are in bundled into fuel assemblies that make up the reactor core.
In the schematic, there is another line going to an analytical laboratory. The fabrication process is not perfect, and measurements are needed within the facility to account for these imperfections. Those measurements on samples are conducted through destructive analysis, where chemistry is used to determine exactly how much enrichment and how much mass is associated with the oxides created. The chemical processes also create waste and leave the facility.
Throughout this whole facility, there are measurement opportunities to provide the facility management with the appropriate understanding of the location, quantity, and form of the material for tracking and management purposes. To account for and manage this entire process, multiple measurements are required—from simple item counting to complex gamma-ray measurements or
neutron measurements or destructive analytical chemistry measurements—to ascertain how material is flowing into the facility and how much material is accumulated in the facility.
Nondestructive assay measurements can be used to confirm enrichment levels for criticality safety. The amount of material that stayed behind in the equipment used for UF6 conversion to UO2 is known as nuclear material holdup. This can create criticality concerns if there is sufficient material in the wrong configuration. Nondestructive assay measurements are therefore conducted to determine how much is left in the pipes. These measurements aid both nuclear safety and accountability. They also provide input into management of nuclear security by helping to determine how much material is in a facility at any given time.
Santi then defined key terminology. An accountability measurement, he stated, “is a measurement to establish the special nuclear material mass value used in an accountancy system for a given item. These are normally high-precision measurements.” The goal is to get about 1 percent or less uncertainty on the mass number for a given item measured. While that is a high degree of precision, if a facility has a sufficiently high throughput, this could, over time, lead to kilograms unaccounted for in a year-in/year-out facility. Note, this is material “unaccounted for” and not “lost.” The material is still within the facility, in holdup, for example, but one simply cannot know exactly where it is at any given time without doing a full clean-out.
“Verification measurements,” Santi explained, “are measurements to positively verify that there is special nuclear material content in a given item. Precisions are about 1 to 5 percent.” The example of the shipper-receive measurement is a verification measurement. A “confirmation measurement” is a qualitative measurement taken to confirm that an item is marked correctly. It can be as simple as item counting. It could be weighing. It could be a measurement done relatively quickly simply to confirm that the item is what it is thought to be.
Nondestructive Assay Measurement Techniques
Santi then focused specifically on nondestructive assay (NDA) measurement techniques. These are techniques which measure a property emanating from the special nuclear material item or assembly of interest that do not force the contents of that item to be disturbed. The properties of the item are determined based on measurements external to the item. He chose to focus on NDA because it is most relevant to nuclear security discussions, since these measurements are used in portal monitors or anything used external to the facility to ensure knowledge of what could potentially leave through unauthorized paths.
There are basically three different NDA measurement techniques. The first is gamma-ray spectroscopy, where the emission of gamma-rays from the material is used to identify its properties (composition). For example, is the item low enriched uranium or highly enriched uranium (HEU): is the item plutonium or
uranium? Gamma-ray spectroscopy will indicate if the item is a simple source, like a cesium source, or if it is a special nuclear material.
Neutron counting is the second NDA technique, which allows one to determine if items are fissioning and at what fission rate. This provides a quantitative estimate of the amount of material in a given container.
The third NDA technique is calorimetry, which is measurement of the heat from the item. All radioactive materials, as they decay, produce thermal heat and that thermal heat can be used, when measured, to determine accurate quantities of associated mass, especially when measuring plutonium or large amounts of HEU.
By combining the information from gamma-ray spectroscopy, neutron counting, and calorimetry, one can determine quantitatively how much nuclear material is in a given item. It is important for accountability to keep track of exactly how much is going from/to different locations and in different configurations. Although a combination of the three techniques is best, even by conducting gamma-ray spectroscopy and neutron counting, control can be better maintained.
Nondestructive assay measurements have several advantages over destructive analysis measurements:
• they normally produce faster result (results within a few minutes),
• measurements can be performed wherever the material is located, and
• no waste is produced and the material is left undisturbed.
Santi noted that there is a role for destructive analysis (DA) in nuclear material accountancy because it provides higher-precision measurements allowing for better accountability numbers. Destructive analysis is better for measuring very small quantities of material: whereas NDA is probably sensitive to gram levels of material, DA is sensitive to much smaller quantities.
NDA is useful in nuclear material security in multiple ways. For example, if a portal monitor is set off, a nondestructive assay measurement will provide more information about what radioisotope caused the alarm. This can help distinguish between causes that are of concern (material illicitly leaving the facility) and those that are not of concern (an employee who underwent a nuclear medical procedure).
NDA is also helpful for domestic safeguards (as distinct from external or international safeguards). At Los Alamos National Laboratory (LANL), for example, NDA measurement is the most frequently implemented measurement technique to reliably determine the characteristics of special nuclear material. In the 1990s, approximately 65 to 75 percent of all Pu inventory measurements were performed with NDA techniques because they can continuously confirm what the inventory is, update the numbers, and provide accountability numbers. Specifically, NDA can play a role in:
• Accountability: determining the book value of a quantity of material in a given item or a given container.
• Confirmatory measurements: ensuring that items that cross boundaries from a material balance area with one set of accounting in one area of a plant to another have consistent values and that the items have not been tampered with since the last measurement.
• Shipper-receiver measurements: ensuring that material passing back and forth from facilities remains the same.
• Process control measurements: ensuring that a process using nuclear material is working appropriately and meets the appropriate quality standards, and that the material will perform to specifications.
Santi underscored that there is always a need to maintain a balance between nuclear security concerns and the ability to use the material. If nuclear security requirements become so onerous that it is simply impractical to work with the nuclear material, the material will not be of value. Using technologies and techniques and material control and accounting to balance and complement nuclear security is a way to maintain as much control over the nuclear material as possible, while still being able to use it for its intended purposes.
Another important issue to remember when dealing with NDAs is that if improper measurements are performed, if erroneous results are received, if there is an inappropriate error bar, or if errors are not accurate with respect to an item, there may be safety implications, especially criticality safety implications. These errors could also have security implications if nuclear material is lost and not detected. Finally, errors could have economic implications if a facility’s resources are continuously utilized to re-measure items that were improperly measured the first time. To avoid errors, personnel within a facility must be able to make these measurements, which requires that they have not only training in how to operate a piece of equipment, but also knowledge of fundamental physics.
Improperly operating portal monitors or improperly trained personnel unable to understand what those portal monitors are detecting or monitoring can lead to other types of errors such as high false-alarm rates, which can lead these alarms being ignored, or if the monitors are not working properly, material may not be detected as it passes through the portal.24
Improper implementation, execution, and interpretation of NDA measurements can lead to a wide range of consequences that can potentially impact the safety or security of a facility. It is up to the personnel who are performing the measurements, ranging from the people who operate the equipment to the professionals who analyze the measurements, to ensure that an NDA measurement is performed properly by taking into consideration a number of different
24 Portal monitors are examples of unattended measurements that are just kept on, running, and they alarm when there is a problem. Attended measurements, which are typically used to determine quantitative information, are taken within a facility to determine how much material is within a given item or a given canister. These types of measurements typically require trained personnel to perform and analyze these measurements.
factors. This includes how an item is packaged, the background radiation levels of the facility, and others.
Santi underscored that not all nuclear facilities are alike. Reactors and other facilities that contain large amounts of material receive a great deal of attention. There are various other facilities that have a smaller amount of nuclear material, such as universities. While it is important to secure this material, a graded approach is best. A university that has a very small amount of nuclear material cannot be treated the same way that a nuclear reactor with a very large amount of nuclear material is treated. Material measurements, then, can aid in developing security strategies. Therefore, in-laboratory or in-field training experiences working with real nuclear materials are important for personnel as they learn techniques and the principles associated with performing these measurements.
Effective training programs may be needed to develop or expand a person’s knowledge and experience with fundamental physics associated with the specific NDA techniques they will be using. This does not mean that all technicians should be trained to become scientists. Principles can be taught that one can remember through lectures and laboratory experiences that become the foundation to build their skills to perform NDA measurements.
A training program needs to discuss not only what a measurement technique can and cannot measure, Santi said, but also with what accuracy and precision they can be measured. It is counterproductive to have someone make a measurement and indicate that the measurement is accurate to 1 percent when it is really only accurate to 10 or 20 percent, or that an NDA measured an item that was 50 grams when the technique was not developed to measure that type of item at all, and it is actually 500 grams. Having the knowledge of what the limitations are for these measurement techniques is important, as is the knowledge of how to properly calculate the resulting uncertainty and present that appropriately.
The training program that Santi directs began in 1973 and has trained individuals who work throughout the Department of Energy complex on how to perform measurements on nuclear materials for accountability. IAEA inspectors began participating in these training courses in 1974, and by 1980 IAEA felt it was so effective for their inspectors that LANL started a dedicated training program for them. Since 1980, every new IAEA inspector hired by the agency has traveled to Los Alamos to learn about the basic principles associated with nondestructive assay techniques, why the technique works, and where it does not work. These programs are customized, which means that if a person just works in a reactor facility, training is focused on that type of facility. The courses utilize an extensive inventory of nuclear material standards, including pure and impure plutonium standards, uranium standards, fresh fuel assemblies, and MOX standards.25 This allows students to see and receive real data, and have
25 A material standard is an object made to exacting specifications (composition, in this case) so that it can serve as a reference point for measurement of other materials.
real experiences in doing the measurements. Since its inception in 1973, LANL has conducted more than 315 courses for about 5,500 students. This has been a successful, ongoing program that continues to produce high-quality results.
In summary, effective nuclear measurements of nuclear material are necessary for the safety, security, and domestic safeguards associated with a facility that uses nuclear material. Performing high-quality measurements requires that the personnel involved in these measurements are appropriately trained, appropriately educated, and that training will then ensure a process of accounting for and securing the nuclear material that is as effective as possible.
During the discussion period, a question was raised about the need to educate the public on various degrees of risk from different types of nuclear versus radiological materials. Rajaraman suggested in response that the public must learn to distinguish among these risks, but because this may be difficult, he suggested beginning with explaining the relative risk from radiological materials. In part this is made more difficult in India, Rajaraman noted, because “for 50 years, we have been training them to be afraid of nuclear materials. It served us very well because it provided us with a nuclear taboo… Now you’re to tell them, yes, be afraid, but don’t be that afraid. This is a difficult and more delicate exercise, but it has to be undertaken if civilian nuclear energy is to survive.”
A workshop participant asked Santi about the relative accuracy of NDA versus DA measurements. Santi replied that research is constantly being conducted to try to reduce the errors of NDA to near zero, or at least much closer to those of DA. He then provided the example of calorimetry of plutonium, which is the more accurate and precise NDA method for measuring plutonium. While one can get down to less than 1 percent or less than .5 percent accuracy, there is a trade-off in time. Calorimetry takes hours for measurements rather than minutes.
This points to another challenge, explained Santi. Researchers continue to try to reduce the amount of materials unaccounted for (MUF) to zero because the material is actually not lost, it is just impossible at present to account for it all. Likewise, there is a high degree of uncertainty about accounting for materials in nuclear waste. Despite efforts to reduce the amount of plutonium or uranium that goes into waste, one cannot eliminate it entirely. MUF, therefore, presents an on-going challenge to facility operators.
Another participant picked up on this point and noted that the challenge of trying to reduce MUF would be an interesting area for cooperation as would the entire issue of measurement control, bringing in the questions of how uncertainties combine, and which measurement methods are particularly problematic. All of these areas challenge experts in both the United States and India because there are really no good answers except additional research.
Santi was asked about NDA and sampling. He confirmed that there is no sampling with NDA; the entire item is measured. Because the entire item is
sampled, the only issues of accuracy come from the ability to interpret signals from the neutrons or the gamma emissions coming from the item. This requires measurement standards to understand how much bias is coming from the system that could cause inaccuracies in measurement.
This reality is replicated in training. Students are shown how the system works in an appropriate situation, where everything works properly. Then the situation is perturbed to show what off-normal situations look like so that students understand when the measurements are not accurate anymore. Essentially what training comes down to is understanding upset conditions and understanding when the situation is not perfect, which is why training should be done in a real laboratory. Realistic situations can then be used as teaching moments, and those are the best ones to have so that students have situational awareness when they perform the measurements.
A participant suggested that Indian scientists and experts would be enthusiastic to work with their counterparts from the United States on NDA, and one suggestion provided by a U.S. participant was to develop additional ways or techniques to help further establish the pedigree or the accuracy with which measurement standards are defined and/or characterized.
The session closed with the remark of a participant who underscored the desire on both sides to collaborate further in these technical areas.
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