Uhlig Lab Logo


Group Information

Research Projects
UROP Opportunities
Our Lab's Capabilities
Group Members
Publications
Getting Here
Links
Contact Us

For Lab Members



Announcements


Questions about the website?
Contact us

Current Research Projects


A Functionally Graded Composite for Resisting Corrosion in Lead-Bismuth Cooled Nuclear Reactors at Temperatures up to 700°C


Professors: Ron Ballinger, Mike Short
Laboratory Staff: Pete Stahle

Abstract: The goal of this project is to develop a Functionally Graded Composite (FGC) to resist liquid Pb-Bi corrosion in Lead Fast Reactors. Currently Lead Fast Reactors are limited at about 600°C by material performance - liquid Pb-Bi corrodes the steel coolant piping and fuel cladding at a very high rate. Steels high in chromium and silicon have been shown to resist Pb-Bi corrosion very well, but they do not retain the tensile strength needed to stay servicable at high (~700°C) temperatures. In addition, silicon alloys become very brittle upon exposure to radiation. In this project we will demonstrate the commercial feasibility of making pipe and tube with a structurally sound wall and a corrosion resistant layer to stop Pb-Bi corrosion. A ferritic/martensitic steel (T91) and an ODS steel (MA957) will be compared in terms of cost and performance.

Project Poster

The researchers wish to thank the US Department of Energy (DoE) NERI program for their generous support.

Edit Project Information
Spinodal Decomposition of Stainless Steel Welds in BWR Reactors


Professors: Ron Ballinger
Laboratory Staff: Pete Stahle
Graduate Students: Tim Lucas
Undergraduate Students: Lauren Ayers

Abstract: Spinodal decomposition is a precipitation process in ferritic Fe-Cr alloys where a phase separation occurs to form Cr-rich and Cr-lean phases in a periodic arrangement. In reference to boiling water reactors (BWR) the concern exists particularly in welds. A better understanding of spinodal decomposition effects on stainless steel welds will allow for improved engineering judgment in terms of the useful lifetime of welds at temperature.

Project Poster

The researchers wish to thank the Tokyo Electric Power Company (TEPCO) for their generous support.

Edit Project Information


Past Research Projects


Attack of SiC and ZrC by Palladium with Applications to the Pebble Bed Modular Reactor


Professors: R. G. Ballinger
Laboratory Staff: Pete Stahle
Graduate Students: Heather MacLean
Undergraduate Students: Mike Short

Abstract: The effects of palladium on silicon carbide (SiC) and zirconium carbide (ZrC) were studied with applications to the Pebble Bed Modular Reactor. Samples of SiC and ZrC were sputter coated with palladium and heated for various times at various temperatures up to 1450K, a characteristic temperature for the PBMR. Upon examination of the samples by SEM microscopy, the SiC samples were observed to have been attacked by palladium, forming Pd2Si and forming channels along grain boundaries. These channels may allow other fission products to escape the kernels. However, palladium was not observed to attack ZrC, as no Pd-Zr phases were observed by X-Ray Diffraction and channels were not observed in the SEM. Instead palladium appeared to collect along grain boundaries and at triple points, suggesting diffusion is the method of Pd migration through ZrC.

The researchers wish to thank the Knowles Atomic Power Laboratory (KAPL) for their generous support.

Edit Project Information
Stress Corrosion Cracking in Alloy X-750 Welds


Professors: Ron Ballinger
Laboratory Staff: Pete Stahle
Graduate Students: Jon P. Gibbs

Abstract: The goal of this project is to determine the rate and mechanism of Stress Corrosion Cracking (SCC) in Alloy X-750, an important new alloy for nuclear reactors. Inconel Alloy X-750 is susceptible to irradiation assisted stress corrosion cracking and intergranular stress corrosion cracking in low temperature (<150°C) and high temperature (>250°C) water. Although X-750 is a mature material, the dominant crack growth mechanisms in nuclear environments are not well understood. This project seeks to understand the dominant mechanisms of crack growth in nuclear environments.

The researchers wish to thank the Idaho National Laboratory (INL) for their generous support.

Edit Project Information
Supercritical CO2 Corrosion Experiments


Professors: Ron Ballinger
Laboratory Staff: Pete Stahle, Tom McKrell
Graduate Students: Jon P. Gibbs, Mike Dunlevy

Abstract: The goal of this project is to determine the rates and mechanisms of corrosion of many important alloys in supercritical CO2.

The researchers wish to thank the Knowles Atomic Power Laboratory (KAPL) for their generous support.

Edit Project Information
Surface Corrosion of Molybdenum Tiles in the Alcator Fusion Reactor


Professors: Ron Ballinger, Dennis Whyte
Laboratory Staff: Pete Stahle
Graduate Students: Joe Hubley

Abstract:

Edit Project Information
The Eff ect of Microstructure on the Fatigue and Fracture Properties of Vintage Power Rotor Steels


Professors: Ron Ballinger
Laboratory Staff: Pete Stahle, Rui Vieira
Graduate Students: Mike Short

Abstract: MIT's Alcator C-Mod fusion experiment makes use of a large spinning mass coupled to a generator as its power source. A signi ficant fraction of this mass consists of a 225 MVA generator rotor that was retired from power plant service. As part of normal maintenance, a periodic inspection by non-destructive evaluation (NDE) is performed to determine if flaws have developed, or progressed from pre-existing conditions, that exceed safe limits for operation. In 2008, after over fifty years of service at a power plant and at Alcator, the organization that performed the most recent inspection recommended that the rotor should not be returned to service. The basis for the rejection of the rotor was not clear, since the inspection did not reveal any change in the distribution of indications by NDE. Moreover, an independent fi tness-for-service evaluation concluded that the rotor was safe to operate. However, the rejection was considered a serious enough event to warrant a more complete analysis of the condition of the rotor prior to continued operation. The cost of replacing or repairing the rotor was prohibitively expensive in terms of capital cost and experimental time lost.

Edit Project Information
Add New Project


NSE Logo
Department of
Nuclear Science & Engineering
MIT Logo

MIT Home Page
DMSE Logo
Department of Materials Science & Engineering