April 2018

April 23, 2018December 19, 2018

Microstructure and mechanical properties of tungsten neutron irradiated with a mixed energy spectrum

SPEAKER:

XUNXIANG HU

RESEARCH STAFF/EUGENE P. WIGNER FELLOW

OAK RIDGE NATIONAL LABORATORY, OAK RIDGE, TN 37931

EMAIL: HUX1@ORNL.GOV

DATE/TIME:

MON, 04/23/2018 - 4:00PM TO 5:00PM

LOCATION:

3105 ETCHEVERRY HALL

Spring 2018 Colloquium Series

Abstract:

Tungsten as a candidate plasma facing material in fusion reactors is confronted by a hostile environment, characterized by high temperature, and high fluxes of heat and particles (D, T, He, and neutrons) when in service. In particular, the 14 MeV-peak neutron irradiation produces displacement damage as well as generating significant concentrations of transmutation elements (i.e., He, Re, Os), resulting in important thermo-mechanical property degradation. In this presentation, the microstructural evolution of tungsten exposed to neutron irradiation at High Flux Isotope Reactor will be introduced as well as the consequential mechanical property degradation.

About the Speaker:

Dr. Xunxiang Hu is currently a Research Staff/Eugene P. Wigner Fellow at the Materials Science and Technology Division at Oak Ridge National Laboratory. He received his PhD in Nuclear Engineering from UC Berkeley in 2013. Before coming to US, he received his Bachelor (2007) and Master (2009) degrees in Nuclear Engineering from Shanghai Jiao Tong University and Tsinghua University in China, respectively. His research is in the field of irradiation effects of materials, and is focused on gas behavior in structural materials used in fission and fusion environments.

April 16, 2018December 19, 2018

Nuclear Disarmament Verification via Resonant Phenomena

SPEAKER:

AREG DANAGOULIAN

ASSISTANT PROFESSOR

DATE/TIME:

MON, 04/16/2018 - 4:00PM TO 5:00PM

LOCATION:

3105 ETCHEVERRY HALL

Spring 2018 Colloquium Series

Abstract:

Nuclear disarmament treaties are not sufficient in and of themselves to neutralize the existential threat of the nuclear weapons. Technologies are necessary for verifying the authenticity of the nuclear warheads undergoing dismantlement before counting them towards a treaty partner’s obligation. A team of scientists working at MIT has developed two novel concepts which leverage isotope-specific nuclear resonance phenomena to authenticate a warhead's fissile components by comparing them to a previously authenticated template. Most actinides such as uranium and plutonium exhibit unique sets of resonances when interacting with MeV photons and eV neutrons. When measured, these resonances produce isotope-specific features in the spectral data, thus creating an isotopic "fingerprint" of an object. All information in these measurement has to be and is encrypted in the physical domain in a manner that amounts to a physical zero-knowledge proof system. Using Monte Carlo simulations and experimental proof-of-concept measurements these techniques are shown to reveal no isotopic or geometric information about the weapon, while readily detecting hoaxing attempts. These new methodologies can dramatically increase the reach and trustworthiness of future nuclear disarmament treaties. The talk will discuss the concepts and recent results, and will give a general overview of nuclear security research pursued at MIT.

About the Speaker:

Areg Danagoulian is an assistant professor at MIT's Department of Nuclear Science and Engineering. His teaching and research focus on leveraging nuclear physics to mitigate the dangers of nuclear materials and weapons. He is currently working on new, monochromatic methodologies for cargo screening as well as technologies for treaty verification via physical cryptography. After completing his PhD in experimental nuclear physics in 2006 at the University of Illinois at Urbana-Champaign, Areg moved to Los Alamos National Laboratory, where he worked on a variety of research areas including stockpile stewardship, physics beyond the standard model, and nuclear security. He then worked for six years in industry, where he developed an award-winning active interrogation system which is currently being used to screen commercial cargoes for the presence of fissionable materials.

April 9, 2018December 19, 2018

Toward Austenitic Oxide Dispersion Strengthened Alloys for Nuclear Applications

SPEAKER:

JAMES STUBBINS, PH.D.

DONALD BIGGAR WILLETT PROFESSOR

DEPARTMENT OF NUCLEAR, PLASMA AND RADIOLOGICAL ENGINEERING

UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN

DATE/TIME:

MON, 04/09/2018 - 4:00PM TO 5:00PM

LOCATION:

3105 ETCHEVERRY HALL

Spring 2018 Colloquium Series

Abstract:

There has been a continuing effort to develop enhanced versions of several types of engineering alloys by strengthening them with a very high number density of very small oxide particles. These particles, if evenly distributed, should provide major improvements in material strength especially at very high temperatures where most engineering metal alloys lose strength. Since the oxide particles are actually ceramics, they should have a very high melting point, much higher than metal alloys, and maintain their stability and strengthening capabilities even at very high temperatures. For nuclear applications where atomic displacement damage takes place, the particles also offer a very large amount of internal surface area which can potentially absorb irradiation-induced defects to reduce radiation damage effects.

This process of making metal alloys with dispersed oxide particles has been attempted in a wide variety of metal systems with some success. There has been a particularly heavy emphasis on developing ODS iron-chromium steels, but much less emphasis on stainless steels. This talk will discuss the possibilities for the development of ODS austenitic steels, which are widely used in current nuclear reactors and are slated for use in a variety of advanced nuclear fission and nuclear fusion reactor systems. The work discusses the microstructure and mechanical behavior of this class of new alloys for nuclear applications.

About the Speaker:

Prof. Stubbins earned his B.S. in Nuclear Engineering at the University of Michigan and his M.S. in Nuclear Engineering and Ph.D. in Materials Science and Engineering at the University of Cincinnati. He held postdoctoral/visiting scientist positions at the Nuclear Research Center, Karlsruhe, Germany and at Oxford University and Harwell Labs in the United Kingdom, before joining General Electric as a Principle Investigator on the US High Temperature Gas-Cooled Reactor Program. He then moved to the University of Illinois were he is now Donald Biggar Willett Professor of Engineering and was formerly Head of the Department of Nuclear, Plasma and Radiological Engineering for the past 18 years. He also holds a Professor appointment in the Japanese World Premier Institute – International Institute for Carbon Neutral Energy Research at Kyushu University, Japan. He is currently a visiting scientist at Los Alamos National Lab and has also held visiting scientist appointments at Argonne National Lab, Oak Ridge National Lab, and Pacific Northwest National Lab in the US and Risø National Lab, Denmark and the University of Pisa, Italy.

April 2, 2018December 18, 2018

Economic Modeling of Nuclear Hybrid Energy Systems

SPEAKER:

DR. CRISTIAN RABITI

DATE/TIME:

MON, 04/02/2018 - 4:00PM TO 5:00PM

LOCATION:

3105 ETCHEVERRY HALL

Spring 2018 Colloquium Series

Abstract:

The increase penetration of variable renewable electricity suppliers in the grid is leading to an increase volatility of the electric net demand (electricity demand minus variable renewable supply). The additional volatility increases the cost of covering net demand and decreases the amount of load that can be classified as base-load. The reduction of the base-load challenges the economics of capital intense suppliers among which nuclear. A possible solution would be the introduction of additional variable load capable to absorb volatility. In particular, if this is done using a direct coupling (steam) between the variable load and the nuclear plant, the benefit could be increased by a better thermal efficiency of the process.

The presentation will focus on the analytical and software framework under construction to perform the needed economic assessments. Early results will be presented and discussed.

About the Speaker:

Dr. Cristian Rabiti is currently the Nuclear Engineering Method Development Department Manager at the Idaho National Laboratory. His areas of expertise are in neutron transport, reactor physics, uncertainty quantification, risk analysis and financial modelling.

Dr. Cristian Rabiti is currently leading the financial modelling of nuclear hybrid energy systems. His particular interest in this field is economic evaluation of nuclear energy by system cost analysis, in a way to conciliate risk analysis with financial performance.

The passion for analysis of stochastic system started when he was leading the RAVEN software development which is currently used for risk analysis, financial modelling, and uncertainty quantification. Dr. Cristian has become since then a strong proponent of advanced validation methodologies and risk analysis.

Dr. Cristian started his career in the development of computational tools in neutron transport and reactor physic. He worked on time dependent transport within the ERANOS tool-suite (FZK-Germany), later he worked on the method of characteristics for the PROTHEUS code (Argonne National Laboratory), and, when he started his job at the Idaho National Laboratory he led the development of the reactor physics core simulator PHISICS (Idaho National Laboratory).

Dr Cristian Rabiti has a PhD in mechanical engineering for the university of Stuttgart (2006) and an MBA from IE Business school (Madrid 2010, Spain)