OPPORTUNITIES AND CHALLENGES IN C0NP 830214 RESEARCH WITH TRANSPLUTONIUM ELEMENTS DE85 010852 Board on Chemical Sciences and Technology Committee on Nuclear and Radlochemistry Commission on Physical Sciences, Mathematics, and Resources National Research Council DISCLAIMER This iw.oort was prepared as an account of work spcnsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsi- bility for the accuracy, completeness, or usefulness of any infonnation, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Refer- ence herein to any specific commercial product, process, or scivice by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recom- mendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. MASTER NATIONAL ACADEMY PRESS Washington, D.C 1983 DISTBIBUHOU OF THIS DOCUMENT IS Workshop Steering Committee Gerhart Friedlander, Brookhaven National Laboratory, Chairman Gregory R. Choppin, Florida State University Richard L. Hoff, Lawrence Livermore National Laboratory Darleane C. Hoffman, Los Alamos Scientific Laboratory, Ex-Officio James A. Ibers, Northwestern University Robert A. Penneman, Los Alamos Scientific Laboratory Thomas G. Spiro, Princeton University Henry Taube, Stanford University Joseph Weneser, Brookhaven National Laboratory Raymond G. Wymer, Oak Ridge National Laboratory, Ex-Officio NRC Staff William Spindel, Executive Secretary Peggy J. Posey, Staff Associate Robert M. Simon, National Research Council Fel"!ow Wendy L. Baker, Administrative Secretary iii PREFACE I am grateful to my colleagues from the United States and abroad, identified in Appendix B, whose intense, dedicated efforts during the workshop produced the panel reports that follow. These reports, together with the individually authored resource papers attached as appendixes, were prepared in response to the U.S. Department of Energy's (DOE) request for an assessment of future directions and prospects for transplutoniuin element research. The workshop clearly showed that the products of the High Flux Isotope Reactor and Transuranium Processing Facility (HFIR/TRU) are essential for tackling many important, even exciting, research problems in nuclear physics and chemistry, in inorganic and metal-organic chemistry, in spectroscopy, and in solid-state sciences. In many instances such research will throw light on questions that go far beyond the narrow confines of the transplutonium elements themselves. These points are, I believe, amply demonstrated in the reports of the workshop panels. I also know from conversations during the workshop that a number of participants who had little prior familiarity with transplutoniura work came away with greatly stimulated interest in and appreciation tor the field. Thus there seems to be little question that, in the general context of chemistry and physics, there is considerable interest in further work with transplutoniuni elements, and the workshop report sets forth the most promising directions for such work as well as the requirements for specific elements and isotopes and the quantities needed. The report does not contain a detailed comparative evaluation of transplutonium research versus other areas of chemistry and physics supported by DOE, because the participants were both unwilling and unable to undertake one. Such an evaluation would require developing priorities for all the chemistry and physics supported by DOE—including research involving transplutoniuni elements—and information on the quantity, quality, and significance of both existing projects and new research proposals in each area. In allocating research resources, one would hardly ever completely eliminate research areas perceived as being of lower priority; one would, instead, support fewer projects in such areas. Clearly, such an undertaking could not have been accomplished by the Steering Committee within the existing time constraints. Furthermore, such responsibilities belong to the program officers of the Office of Basic Energy Sciences. Their skill and foresight is the key to making proper judgments, in terms of DOE's long-range mission and the nation's needs, in the selection of research proposals to support. I am confident that the workshop, by identifying exciting research areas, will provide useful guidance to program officers in making such choices. Nevertheless, I sympathize with the difficulty faced by the DOE staff. The operation of the HF1R/TRU is so expensive that it represents a sizable fraction of the total Division of Chemical Science's budget, and its support is perceived by some as cutting into the support of other areas. In this context two remarks seem germane: (1) The uniqueness of the fact that its support is essentially an all-or-nothing matter (it cannot be cut by 20 percent) should weigh heavily in comparison with other areas. In other words, one must consider whether an entire field should be irrevocably wiped out in favor of increased support for many other small-science programs, worthy as they may be. (2) It is obviously not fair to consider the cost of the HFIR/TRU only in the context of the Division of Chemical Sciences, even though the program is funded through and administered by that office. The benefits are shared by nuclear science, solid-state science, and chemistry, and one should therefore look at the HFIR/TRU budget in relation to the overall Basic Energy Sciences' budget to put it in perspective. My sincere thanks go to William Spindel and his staff (Peggy Posey, Robert Simon, Wendy Baker, and Frances E. Holland) for invaluable support in organizing and operating the workshop and in preparing this report. Gerhart Friedlander Chairman vi CONTENTS Preface v Overview and Recommendations 1 Panel Reports 1. Nuclear Reactions and Synthesis of New Species 7 2. Nuclear Properties of the Transplutonium Elements 25 3. Chemical Properties of the Transplutonium Elements 41 4. Spectroscopy of the Transplutoniuai Elements 65 5. Solid-State Physics and Chemistry of the Transplutonium Elements 79 Appendixes A. Letter from E.S. Pierce 101 B. Participants and Panel Organization 103 C. The Oak Ridge Transplutonium Production Program - 109 O.L. Keller, Jr. D. Nuclear Reactions and Synthesis of New Transuranium 143 Species - G.T. Seaborg E. Directions for Nuclear Research in the Transplutonium 181 Elements - J.B. Wilhelmy, R.R. Chasman, A.M. Friedman, and I. Ahmad F. The Chemistry of the Transplutonium Elements - 231 R.A. penneman and G.R. Choppin G. Spectroscopic Studies of the Transplutoniura Elements - 287 W.T. Carnall and J.G. Conway H. Magnetic and Solid State Properties - N. Edelstein, 299 B. Johansson and J.L. Smith I. Industrial Usage of Californium-252 - E.F. Janzow 309 J. Cf-252: New Radioisotope for Human Cancer Therapy - 33S Y. Maruyama vii OVERVIEW AND RECOMMENDATIONS ORGANIZATION AND OPERATION OF THE WORKSHOP Since their constn ction in the mid-1960s, the High Flux Isotope Reactor (HFIR) and the associated Transuranium Processing Facility (TRU) at Oak Ridge National Laboratory have provided the western world's supply of elements beyond curium (atomic number 96), either directly or by furnishing starting materials for further nuclear-synthesis reactions. Both facilities have a remarkable record of reliability and minimal downtime. Despite the uniqueness of the HFIR/TRU complex, "the transplutonium element area has increasingly received special attention because of its high costs relative to those of other areas," as stated in a letter (see Appendix A) from Dr. Elliot S. Pierce, Director of the Division of Chemical Sciences of the U. S. Department of Energy's (DOE) Office of Basic Energy Sciences (OBES), which provides most of the funding for these facilities. As a result of this special concern, OBES asked the National Research Council (NRC) to convene a Workshop on Future Directions in Transplutonium Element Research. The specific charge for the workshop, as stated in the invitation to participants, was "to provide DOE with an assessment of the importance and future directions of research with these elements, viewed in the broader context of chemistry and physics." The workshop was organized under the auspices of the NRC's Board on Chemical Sciences and Technology and its Committee on Nuclear and Radiochemistry, which jointly selected a steering committee composed about equally of active actinide researchers and other chemists and physicists. Attendance at the workshop was by invitation, and participants were carefully selected to represent practitioners In the various areas of research with transplutonium elements as well as experts in related fields not themselves working with these materials. The participants are listed in Appendix B. To provide background material for the workshop, a number of experts prepared resource papers that were distributed to the workshop participants and that also served as the basis of oral presentations to the opening plenary session of the workshop. These papers are appended to this report as Appendixes C through J. Following the initial plenary session, the participants formed five panels concerned with the following aspects of transplutonium