USA - PNNL

BATTELLE, PACIFIC NORTHWEST NATIONAL LABORATORY

P.O. Box 999, Battelle Boulevard, Richland, Washington 99352

Telephone: +1 509 373 7515
Telefax: +1 509 376 0418

Director:

Powell, Lura J.

Materials Sciences Department (Tel.: +1 509 375 3676)

Pederson, Larry R. (Department Manager)
Kurtz, Richard J. (Fusion Materials Program Manager)

Edwards, Danny J.
Garner, Francis A.
Gelles, David S.

Greenwood, Lawrence R.
Heinisch, Howard L.
Jones, Russell H.

Senor, David J.
Youngblood, Gerald E.

Research activities:
Battelle Memorial Institute operates the Pacific Northwest National Laboratory for the U. S. Department of Energy. PNNL performs research to develop and characterize advanced materials for the first-wall and blanket structures of magnetic fusion power systems. The long-term objective of the program is to enhance the economic and environmental attractiveness of the fusion energy option. The scope of work includes developing new materials with improved properties and low-activation characteristics, investigating the response of candidate materials to neutron irradiation and establishing predictive capabilities through theory and modeling of the effect of neutron irradiation on material properties. This predictive capability is needed to account for differences in the neutron spectrum between fission reactors, where irradiation experiments are currently performed, and the fusion neutron environment.

Alloy Development
Fusion power systems will subject structural materials to severe radiation environments for long periods of time. A major challenge to materials scientists is to develop materials with increased resistance to radiation and chemical environments, leading to longer component life. Furthermore, reducing the radioactivation of these materials will decrease waste disposal costs and enhance the environmental acceptability of fusion power. This means developing new alloys that avoid or minimize use of some conventional constituents such as nickel and molybdenum. Only a limited number of materials potentially possess the physical, mechanical and low-activation characteristics required for fusion power. Consequently, the research effort is limited to three candidate material systems: ferritic-martensitic steels, vanadium alloys, and silicon carbide composites. The program includes an irradiation program. Post-irradiation examinations include mechanical testing, analysis of dimensional changes, and electron microscopy, with strong emphasis on developing fundamental understanding of observed effects in order to lead materials design.

Damage Analysis and Fundamental Studies
Methods are being developed for predicting the performance of candidate structural materials from data obtained in fission reactor and accelerator-based neutron irradiation facilities. The program emphasizes understanding radiation effects on materials. Activities include theoretical modeling computer simulation studies of radiation damage mechanisms, carefully controlled experimentation with engineering materials to study effects of neutron flux, spectrum, transmutations, etc., and the development of correlations between properties and service exposure conditions.

Recent Accomplishments

1. atomic scale computer annealing simulations for studying defect migration kinetics in irradiated metals
2. exploration of post-irradiation deformation mechanisms in ferritic steels
3. characterization of the high-temperature creep properties of vanadium-based alloys
4. micromechanical modeling of subcritical crack growth mechanisms in fiber reinforced silicon carbide composites
5. development of novel experimental techniques to determine mechanical property data, microchemistry, and microstructural information on irradiated metals from a single TEM disk
6. investigation of the post-irradiation annealing behavior of copper alloys at low temperatures and doses