Amorphization of Laves-Phase Precipitates in Zircaloy-4 by Neutron Irradiation

Conference · Fri Apr 23 04:00:00 EDT 1999

OSTI ID:8219

Peters, H R ^[1]; Taylor, D F; Yang, Walter J.S.

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1. Lockheed Martin Corp., Schenectady, NY

Examination of corrosion coupons by transmission electron microscopy after their exposure in the Idaho Advanced Test Reactor (ATR) has broadened the Zircaloy-4 precipitate-amorphization database and validated a new kinetic model for previously unavailable values of temperature and fast-neutron flux. The model describes the amorphization of Zr(Fe,Cr){sub 2} intermetallic precipitates in zirconium alloys as a dynamic competition between radiation damage and thermal annealing that leaves some iron atoms available for flux-assisted diffusion to the zirconium matrix. It predicts the width of the amorphous zone as a function of neutron flux (E>1 MeV), temperature, and time. In its simplest form, the model treats the crystalline/amorphous and precipitate/matrix interfaces as parallel planes, and its accuracy decreases for small precipitates and high fluence as the amorphous-zone width approaches precipitate dimensions. The simplest form of the model also considers diffusion to be rate-determining. This is an accurate approximation for steady-state conditions or slow changes in flux and temperature, but inappropriate for the analysis of faster transients. The paper addresses several difficulties inherent in measuring amorphous-zone width, and utilizes the expanded database to evaluate the improvements in predictive accuracy available through both conversion of the model to spherical coordinates and extension of its time dependency.

• Research Organization: Knolls Atomic Power Lab., Niskayuna, NY (US)
• Sponsoring Organization: USDOE Office of Nuclear Energy, Science and Technology (NE) (US)
• DOE Contract Number: AC12-76SN00052
• OSTI ID: 8219
• Report Number(s): KAPL-P-000214
• Country of Publication: United States
• Language: English

Related Subjects

29 ENERGY PLANNING, POLICY, AND ECONOMY
36 MATERIALS SCIENCE
ATR REACTOR
IRRADIATION
NEUTRON FLUX
NEUTRONS
NUCLEAR POWER
STEADY-STATE CONDITIONS
TRANSMISSION ELECTRON MICROSCOPY
ZIRCALOY 4
ZIRCONIUM ALLOYS