Uncertainty Analyses of Advanced Fuel Cycles

Abstract

Alternative fuel cycles, 3) Impact of Time-of-implementation of alternative fuel cycles. 4) Use high burnup fuel (i.e. 70 GWth-d/tonne), 5) Reprocessing of LWR fuel, 6) Use Mixed Oxide (MOX) fuel, 7) Introduction of FRs in to the LWR fleet, 8) Inventories of Plutonium (Pu) and other actinides in and out of reactors, 9) Economic impact of alternative fuel cycles, and 10) Uncertainties of parameters and outcomes. Salient issues associated with these topics are addressed in the main body of this report and details are presented in the appendices. The MIT Report on the Future of Nuclear Energy 2 claims that the availability of uranium is not the limiting constraint for expanding the use of nuclear energy. Instead, economics, waste management, proliferation, and public acceptance are more important than uranium resources. Wineberg 1 claims that the use of breeder reactors is necessary for nuclear power to have a long-term impact on human energy consumption; where "longterm" is several thousand years. The MIT article appears to be focused of electrical energy usage during the relatively near future, such as the next hundred years. Thus, there is not a real contradiction, but only a difference in perspective. The Department of Energy (DOE) recognizes the need for the development of advanced reactors and advanced fuel cycles to assure that the use of nuclear fission remains a viable option for production of electrical power. In particular, it supports the Generation IV reactor development program, and it supports the Advanced Fuel Cycle Initiative of alternative fuel cycles with a focus on Generation IV systems 3. Sustainability is an important issue relative to choices for fuel cycles and for reactor systems. In particular, the following conditions should be satisfied for sustainability: 1) The fuel supply should last for several thousand years, 2) The radioactive materials produced from operation should be effectively managed and not exceed the original activity of ore after about one thousand years, 3) Materials required to construct and operate reactors should be in adequate supply, and 4) Byproducts of operation should not create a significant risk, which includes proliferation of nuclear weapons. Sustainability issues considered to be important are as follows: 1) Resources, 2) Environmental Effects, 3) Economics, 4) Societal Impacts, 5) Proliferation, 6) Infrastructure Commitments, 7) Waste Management, and 8) Vulnerability for Disruptions. These topics are discussed in Appendix B. Fuel Cycles of Interest and Repository Issues The transuranics and minor actinides (MA) in spent fuel from reactors use the Pu/U fuel cycle may be disposed of directly with the spent fuel, or they can be separated for subsequent disposition or use in reactor facilities. Implementation of practices that manage these transuranics require investments in support facilities and infrastructure that competes with the much more straightforward practice of direct disposal of spent fuel. Some of the generic fuel cycle concepts under consideration t...

Evaluation of Prior Authorization in Medicare Nonemergent Ambulance Transport

“…Prior authorization is a strategy used by many private and public health insurers to contain costs and improve the integrity of billing and treatment. 1 It is used across a wide array of services, including surgeries, hospital inpatient admissions, drugs, home health, and physical therapy. In the Medicare fee-for-service program, the Centers for Medicare & Medicaid Services (CMS) has focused prior authorization on a smaller set of services with documented high levels of improper payments and unnecessary use, which we refer to here as services vulnerable to improper use.…”

“…Previous studies found that prior authorization was associated with reduced spending for the targeted medication or service, though in some cases this association waned over time. [1][2][3][4][5][6][7][8][9] Findings related to the association of prior authorization with total cost of care are mixed, and there is limited evidence on changes in hospitalizations, emergency department visits, time to treatment, patient length of stay, or access to treatment. 1,3,7,10 By examining total cost of care and a series of patient outcomes and access to care measures, not just spending for the target service, this study is able to assess the potential for targeted prior authorization programs to improve efficiency in the Medicare program without a change in beneficiaries' health.…”