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Title: Radiation-induced instability of MnS precipitates and its possible consequences on IASCC of austenitic stainless steels

Abstract

Irradiation assisted stress corrosion cracking (IASCC) continues to be a significant materials issue for the light water reactor industry and may also pose a problem for fusion power devices that employ water cooling. Although a number of potential mechanisms have been proposed to participate in this phenomenon, at this time it is not clear that any of these candidate mechanisms are sufficient to rationalize the observed failures. A new mechanism is proposed in this paper that involves the radiation-induced release into solution of elements not usually thought to participate in IASCC. It is shown in this paper that MnS precipitates, which contain most of the sulphur in stainless steels, are probably unstable under irradiation. First, the Mn transmutes very strongly to Fe in highly thermalized neutron spectra. Second, the combination of cascade-induced disordering and the inverse-Kirkendall effect operating at the incoherent interfaces of MnS precipitates will probably act as a pump to export Mn from the precipitate surface into the alloy matrix. Both of these processes will most likely allow some of the sulphur to re-enter the alloy matrix. Sulphur is known to exert a deleterious influence on grain boundary cracking. MnS precipitates are also thought to be a reservoirmore » of other deleterious impurities such as fluorine which could be also released due to radiation-induced instability of the precipitates. This possibility has been confirmed by Auger electron spectroscopy of Types 304, 316, and 348 stainless steel specimens sectioned from several BWR components irradiated up to 3.5x10{sup 21} n/cm{sup 2} (E > 1 MeV).« less

Authors:
 [1];  [2]
  1. Argonne National Lab., IL (United States)
  2. Pacific Northwest National Lab., Richland, WA (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab., TN (United States)
OSTI Identifier:
414883
Report Number(s):
DOE/ER-0313/20
ON: DE97000700; TRN: 97:001402
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: Oct 1996; Related Information: Is Part Of Fusion materials semiannual progress report for the period ending June 30, 1996; PB: 358 p.
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; STAINLESS STEEL-304; PHYSICAL RADIATION EFFECTS; STRESS CORROSION; STAINLESS STEEL-316; STAINLESS STEEL-348; MANGANESE SULFIDES; INSTABILITY; PROGRESS REPORT; NEUTRONS; REACTOR MATERIALS

Citation Formats

Chung, H. M., and Garner, F. A. Radiation-induced instability of MnS precipitates and its possible consequences on IASCC of austenitic stainless steels. United States: N. p., 1996. Web. doi:10.2172/414883.
Chung, H. M., & Garner, F. A. Radiation-induced instability of MnS precipitates and its possible consequences on IASCC of austenitic stainless steels. United States. doi:10.2172/414883.
Chung, H. M., and Garner, F. A. Tue . "Radiation-induced instability of MnS precipitates and its possible consequences on IASCC of austenitic stainless steels". United States. doi:10.2172/414883. https://www.osti.gov/servlets/purl/414883.
@article{osti_414883,
title = {Radiation-induced instability of MnS precipitates and its possible consequences on IASCC of austenitic stainless steels},
author = {Chung, H. M. and Garner, F. A.},
abstractNote = {Irradiation assisted stress corrosion cracking (IASCC) continues to be a significant materials issue for the light water reactor industry and may also pose a problem for fusion power devices that employ water cooling. Although a number of potential mechanisms have been proposed to participate in this phenomenon, at this time it is not clear that any of these candidate mechanisms are sufficient to rationalize the observed failures. A new mechanism is proposed in this paper that involves the radiation-induced release into solution of elements not usually thought to participate in IASCC. It is shown in this paper that MnS precipitates, which contain most of the sulphur in stainless steels, are probably unstable under irradiation. First, the Mn transmutes very strongly to Fe in highly thermalized neutron spectra. Second, the combination of cascade-induced disordering and the inverse-Kirkendall effect operating at the incoherent interfaces of MnS precipitates will probably act as a pump to export Mn from the precipitate surface into the alloy matrix. Both of these processes will most likely allow some of the sulphur to re-enter the alloy matrix. Sulphur is known to exert a deleterious influence on grain boundary cracking. MnS precipitates are also thought to be a reservoir of other deleterious impurities such as fluorine which could be also released due to radiation-induced instability of the precipitates. This possibility has been confirmed by Auger electron spectroscopy of Types 304, 316, and 348 stainless steel specimens sectioned from several BWR components irradiated up to 3.5x10{sup 21} n/cm{sup 2} (E > 1 MeV).},
doi = {10.2172/414883},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1996},
month = {10}
}