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Division Spotlight
Nuclear Nonproliferation Policy
The mission of the Nuclear Nonproliferation Policy Division (NNPD) is to promote the peaceful use of nuclear technology while simultaneously preventing the diversion and misuse of nuclear material and technology through appropriate safeguards and security, and promotion of nuclear nonproliferation policies. To achieve this mission, the objectives of the NNPD are to: Promote policy that discourages the proliferation of nuclear technology and material to inappropriate entities. Provide information to ANS members, the technical community at large, opinion leaders, and decision makers to improve their understanding of nuclear nonproliferation issues. Become a recognized technical resource on nuclear nonproliferation, safeguards, and security issues. Serve as the integration and coordination body for nuclear nonproliferation activities for the ANS. Work cooperatively with other ANS divisions to achieve these objective nonproliferation policies.
Meeting Spotlight
Utility Working Conference and Vendor Technology Expo (UWC 2024)
August 4–7, 2024
Marco Island, FL|JW Marriott Marco Island
Standards Program
The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
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Latest News
ARPA-E announces $40 million to develop transmutation technologies for UNF
The Department of Energy’s Advanced Research Projects Agency–Energy (ARPA-E) announced $40 million in funding to develop cutting-edge technologies to enable the transmutation of used nuclear fuel into less-radioactive substances. According to ARPA-E, the new initiative addresses one of the agency’s core goals as outlined by Congress: to provide transformative solutions to improve the management, cleanup, and disposal of radioactive waste and spent nuclear fuel.
Seong-Wan Hong, Beong-Tae Min, Seong-Ho Hong
Nuclear Technology | Volume 191 | Number 2 | August 2015 | Pages 122-135
Technical Paper | Fuel Cycle and Management | doi.org/10.13182/NT14-84
Articles are hosted by Taylor and Francis Online.
Steam explosions by the interaction of molten corium with water have been studied extensively because they may have the potential to impact the integrity of the containment. Since breakup and fragmentation processes during premixing are important mechanisms that influence steam explosion behavior, the particle size distribution characteristics on fuel-coolant interaction (FCI) have been investigated in the TROI (Test for Real cOrium Interaction with water) test facility.
The data characteristics indicate that FCI characteristics depend upon the composition of the prototypic corium material, and the particle size of the debris is related to the intensity of the dynamic pressure produced by an explosion. The mass mean diameters of the debris produced by explosive compositions were less than that of the nonexplosive compositions. A mass mean diameter of 2 mm was found to be a boundary size produced by a steam explosion of corium. The particle sizes of the molten corium involving a steam explosion were shown to be mainly 3 to 6 mm depending on the material and composition, but the size distribution shifted to smaller sizes if a steam explosion occurred. Small corium droplets of less than ∼3 mm did not seem to contribute to a steam explosion owing to solidification at an early stage before the explosion, but large droplets contributed due to their liquid state.
Zirconia, with the largest fusion heat, has almost always exploded, and the explosions have been energetic, while the eutectic composition (UO2/ZrO2 = 70/30 at weight percentage) frequently exploded. On the other hand, noneutectic compositions rarely exploded, even though the heat of the fusion was very similar to the eutectic composition that frequently exploded. The main reason why noneutectic corium compositions do not explode seemed to be that they undergo solidification by forming a “mushy zone” with a small freezing temperature range. To determine whether noneutectic corium melts cooled down through the mushy zone, particles of this composition were analyzed from the surface inward using a scanning electron microscope, an electron probe microanalyzer, and X-ray diffraction. However, all particles were found to have a homogeneous solid solution. The large particles showed the typical solidification shapes of a general molten material. The small particles generally had only a few small pores and small cracks. The morphologies of the large and small particles were found to be similar.