Enhanced corrosion of zirconium-based alloys in proximity to other metals : the "shadow effect"

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 2000.

Bibliographic Details
Main Author: Châtelain, Anthony R. (Anthony Roger), 1972-
Other Authors: Ronald G. Ballinger.
Format: Thesis
Language:eng
Published: Massachusetts Institute of Technology 2005
Subjects:
Online Access:http://hdl.handle.net/1721.1/8871
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author Châtelain, Anthony R. (Anthony Roger), 1972-
author2 Ronald G. Ballinger.
author_facet Ronald G. Ballinger.
Châtelain, Anthony R. (Anthony Roger), 1972-
author_sort Châtelain, Anthony R. (Anthony Roger), 1972-
collection MIT
description Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 2000.
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spelling mit-1721.1/88712022-01-25T21:09:37Z Enhanced corrosion of zirconium-based alloys in proximity to other metals : the "shadow effect" Châtelain, Anthony R. (Anthony Roger), 1972- Ronald G. Ballinger. Massachusetts Institute of Technology. Dept. of Nuclear Engineering. Massachusetts Institute of Technology. Department of Nuclear Engineering Massachusetts Institute of Technology. Department of Nuclear Science and Engineering Nuclear Engineering. Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 2000. Includes bibliographical references. Fuel cladding for water-cooled power reactors must meet certain requirements for optimal performance. To function in the extreme conditions typical of a nuclear reactor core the material used must be corrosion resistant, have low thermal neutron cross section, and high strength. Corrosion resistance is one of the most important parameters for reactor materials. From the beginning of the use of reactors, engineers have been faced with the problem of excessive corrosion in several different forms. In recent years, a peculiar corrosion phenomenon has increased in significance. Several occurrences of local corrosion enhancement of zirconium-base alloys in proximity to other components have been observed. This corrosion enhancement talcs the form of a "shadow" of a metal component in proximity, hence its name, "shadow effect." Although much recent attention has been given to the shadow effect, it has been known since the sixties, but has only lately been considered a possible threat to material integrity. Today the interest in local corrosion enhancement due to the shadow effect and its implications for in-core performance of cladding and structural material is increasing worldwide. International experience has shown that the phenomenon has occasionally resulted in serious corrosion problems threatening material integrity. In order to prevent future obstruction from the phenomenon an understanding of the shadow effect needs to be developed. This becomes important in today's rapid expansion of aggressive reactor environments with higher burn-up and the need for longer fuel residence times for more economical runs. This project was conducted at MIT, funded by ABB Atom, which had the goal of identifying the basic mechanisms of the shadow effect. The MIT research reactor MITR-11 was used to simulate BWR core coolant conditions. The sample train included Zr-2- alloy with various surface treatments. Different counter electrodes surrounded each cladding piece. They were high and low beta emitters, inert material and Zircaloy-2 in contact and non-contact at various separation distances. Post-irradiation examination of the cladding pieces showed: * Beta-radiation is not the main mechanism for the shadow effect. * Shadow corrosion is partly dominated by an electrochemical mechanism. * Radiolysis plays an important role for the formation of shadow corrosion. by Anthony R. Châtelain. S.M. 2005-08-23T15:59:22Z 2005-08-23T15:59:22Z 2000 2000 Thesis http://hdl.handle.net/1721.1/8871 48765568 eng M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 253 p. 15383113 bytes 15382869 bytes application/pdf application/pdf application/pdf Massachusetts Institute of Technology
spellingShingle Nuclear Engineering.
Châtelain, Anthony R. (Anthony Roger), 1972-
Enhanced corrosion of zirconium-based alloys in proximity to other metals : the "shadow effect"
title Enhanced corrosion of zirconium-based alloys in proximity to other metals : the "shadow effect"
title_full Enhanced corrosion of zirconium-based alloys in proximity to other metals : the "shadow effect"
title_fullStr Enhanced corrosion of zirconium-based alloys in proximity to other metals : the "shadow effect"
title_full_unstemmed Enhanced corrosion of zirconium-based alloys in proximity to other metals : the "shadow effect"
title_short Enhanced corrosion of zirconium-based alloys in proximity to other metals : the "shadow effect"
title_sort enhanced corrosion of zirconium based alloys in proximity to other metals the shadow effect
topic Nuclear Engineering.
url http://hdl.handle.net/1721.1/8871
work_keys_str_mv AT chatelainanthonyranthonyroger1972 enhancedcorrosionofzirconiumbasedalloysinproximitytoothermetalstheshadoweffect