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Devoted specifically to the safety of nuclear installations and the health and safety of the public, this division seeks a better understanding of the role of safety in the design, construction and operation of nuclear installation facilities. The division also promotes engineering and scientific technology advancement associated with the safety of such facilities.
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ANS Student Conference 2025
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Latest News
First astatine-labeled compound shipped in the U.S.
The Department of Energy’s National Isotope Development Center (NIDC) on March 31 announced the successful long-distance shipment in the United States of a biologically active compound labeled with the medical radioisotope astatine-211 (At-211). Because previous shipments have included only the “bare” isotope, the NIDC has described the development as “unleashing medical innovation.”
Dwayne A. Chesnut
Nuclear Technology | Volume 104 | Number 2 | November 1993 | Pages 182-192
Technical Paper | Special Issue on Waste Management / Radioactive Waste Management | doi.org/10.13182/NT93-A34882
Articles are hosted by Taylor and Francis Online.
Waste packages for a U.S. nuclear waste repository are required to provide reasonable assurance of maintaining substantially complete containment of radionuclides for 300 to 1000yr after closure and of permitting only controlled release of radionuclides for 10000 yr. The waiting time to failure for complex failure processes affecting engineered or manufactured systems is often found to be an exponentially distributed random variable. Assuming that this simple distribution can be used to describe the failures of hypothetical singlebarrier waste packages, bounding calculations show that the mean time to failure would have to be >107 yr in order to provide reasonable assurance of meeting this requirement. If such a waste package could be manufactured, it would be practically impossible to demonstrate its performance within the repository preclosure time of 40 yr. With two independent barriers, each would need to have a mean time to failure of only 105 yr to provide the same reliability, illustrating that the use of redundant independent barriers is the key to both achieving and demonstrating regulatory compliance. However, even this demonstration would require testing tens of thousands of two-barrier systems for several decades. As more barriers are added, the mean lifetime required of each individual barrier decreases, and the demonstration of performance becomes more feasible, although still requiring extensive testing and observation during the preclosure period for performance confirmation. In any case, the results illustrate that neither the engineered barrier system nor the geologic barrier system alone is likely to provide the required degree of assurance of repository safety.