Editorial

Nuclear Materials Including "Orphans" Require a Comprehensive Management Strategy

."Nuclear materials" is a generic term meaning materials of interest to the nuclear industry, sometimes synonymous with "source" and "special materials," as listed in the Atomic Energy Commission Manual. A vast knowledge base has been generated over the past six decades to safely manage all nuclear materials to maximize their benefits and minimize their hazards. However, it should be recognized that the knowledge base was not always adequate nor effectively used in the preservation and use of these materials. As a result, many environments have been impacted by nuclear materials, and the potential for impacting more still exists. Therefore, it is important to develop a comprehensive strategy to better manage these valuable resources for the future.

A recent estimate by the Brookings Institution points out that the United States spent over $5.5 trillion during the past five decades to build and maintain nuclear defense capabilities, almost $1 trillion of this in nuclear materials production and related activities. Under a series of Congressional initiatives, the DOE has the major responsibilities for long-term management of all nuclear materials from the defense sector and a major portion of those originating from the civilian sector. Currently, numerous programs address the long-term management of materials for national security (including those resulting from weapons dismantlement, nuclear wastes, spent nuclear fuels, and contaminated sites and facilities). These programs are at various stages of development, demonstration, and implementation. Our ability to achieve the goals of our excess fissile material disposition programs is dependent on complex international agreements and is likely to take many decades. A large inventory of nuclear materials originating within and outside of national security programs exists in addition to those necessary for national security or declared excess. These may be properly described as "orphan nuclear materials." The disposition of orphan nuclear materials is still awaiting recognition and resource allocations. A preliminary but incomplete estimate made last year identified over 30,000 records of 72 million curies of miscellaneous radioactive materials. The actual numbers may be many times those identified last year.

Figure 1. Scott Allen and George Powell (BUS-4) may be called upon to recover and transport neutron sources widely used in oil and gas well logging. Nuclear material "orphans" such as these sources pose a problem for the managed disposal of excess nuclear materials.

A unique example of orphan nuclear materials is the man-made neutron sources that are used extensively in defense projects, industries, universities, and research organizations. Most of these neutron sources consist of homogeneous mixtures of an alpha- or gamma-emitting radionuclide and a low-atomic-number element or its compound. It is estimated that there are several hundred thousand such sources now in use within the U.S., and about 3,000 are being produced and distributed annually (Figure 1) . A 1985 Congressional mandate makes the DOE responsible for receiving abandoned, damaged, and returned neutron sources and disposing of them in an environmentally benign fashion. Inappropriate disposition of these sources has the potential to cause extreme hazard to human beings and irreparable harm to the environment (Figure 2). Los Alamos National Laboratory spent many years to develop a simple, elegant method (chemical separation flow sheet) to separate the two components of the neutron sources. This technology was successfully demonstrated in dismantling over a thousand neutron sources and making them innocuous and environmentally benign. Unfortunately, the implementation of this elegant technology to address large-scale disposition of neutron sources is now in doubt.

Present challenges to nuclear materials management are too numerous for extensive discussion here. There is, however, a tacit recognition that a common strategic framework is necessary to avoid the environmental blunders of the past. During the past decade, a series of studies and assessments have been performed to identify and quantify the needs of nuclear materials management.

On January 20, 1998, the DOE Office of the Deputy Assistant Secretary for Nuclear Material and Facility Stabilization initiated the Nuclear Material Integration (NMI) Project. The goals of the NMI were to inventory and analyze the nuclear materials in the DOE Complex. The scope of this project included not only materials owned by the Office of Environmental Management (EM) but also those owned by other programs and stored in EM facilities. The ultimate goal of this effort was to develop a comprehensive nuclear material management plan for the nation.

Figure 2. A damaged americium-beryllium neutron source recovered from a private company by Los Alamos.

Three material management teams were responsible for the different groups of materials in the DOE Complex: the Transuranic Team, responsible for most transuranic elements; the Uranium/Thorium Team, responsible for most uranium and thorium materials; and the Nonactinide Isotope and Sealed Sources Team, responsible for all radioactive isotopes with an atomic number less than 90, and all sealed sources, irrespective of atomic number. About 250 people from across the country participated in developing data and strategies for the management of all the "excess" nuclear materials within the DOE complex and those that are likely to become DOEšs responsibility in the future. The three teams prepared a total of twelve independent reports (nuclear material management plans) and submitted them to DOE/EM in 1998. Separate materials management plans were prepared for depleted uranium, high-enriched uranium, low-enriched uranium, natural uranium, nonactinide isotopes, ²⁴¹Am, ²³⁷NP and ²³⁸Pu, ²³⁹Pu, ²⁴²Pu, thorium, transuranic heavy elements, and ²³³U. These reports are presently considered "predecisional draft documents" and are not yet available for general distribution.

While many such studies have developed valuable data, heretofore, follow-up actions have been disappointing. Missing in previous follow-up actions is the desire to address the problem as a national or societal issue. Instead it is always addressed as the issue relevant to a particular agency of the government or a subordinate bureaucracy interested only in simplistic solutions. It is this approach that ought to change to achieve the goals of a comprehensive strategy to manage all nuclear materials for the benefit of mankind and to instill public confidence in associated technologies and institutions.

In the best traditions of U.S. science, an objective evaluation of the recommendations made by the NMI teams has been requested by an independent organization, the National Academy of Sciences. DOE/EM is championing the cause for an Academy study to review the 12 reports. However, this study is still waiting because of limited DOE resources. It is to be hoped that the Academy will evaluate the reports, and that their recommendations will include comprehensive management and preservation of nuclear materials, including neutron sources and other "orphans," that are generated by both the defense and civilian sectors. It is also to be hoped that such recommendations will be implemented in a timely manner.

K. K. S. Pillay is the Project Leader for Waste Management, NMT-DO.

The opinions in this editorial are mine; they do not necessarily represent the opinions of Los Alamos National Laboratory, the University of California, the Department of Energy, or the U.S. Government.

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