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Title: SCC Controls

Authors:
 [1];  [1]
  1. Los Alamos National Laboratory
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
DOE/LANL
OSTI Identifier:
1134296
Report Number(s):
LA-UR-14-24259
DOE Contract Number:
AC52-06NA25396
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
Energy Conservation, Consumption, & Utilization(32); Energy Planning, Policy, & Economy(29); Engineering(42); Other Instrumentation(47)

Citation Formats

Montoya-Wiuff, Alynna C., and Ferguson, Michael R. SCC Controls. United States: N. p., 2014. Web. doi:10.2172/1134296.
Montoya-Wiuff, Alynna C., & Ferguson, Michael R. SCC Controls. United States. doi:10.2172/1134296.
Montoya-Wiuff, Alynna C., and Ferguson, Michael R. Wed . "SCC Controls". United States. doi:10.2172/1134296. https://www.osti.gov/servlets/purl/1134296.
@article{osti_1134296,
title = {SCC Controls},
author = {Montoya-Wiuff, Alynna C. and Ferguson, Michael R.},
abstractNote = {},
doi = {10.2172/1134296},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Jun 11 00:00:00 EDT 2014},
month = {Wed Jun 11 00:00:00 EDT 2014}
}

Technical Report:

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  • Alloy 600 corrosion coupon tests were performed: (1) to quantify the temperature dependency of general corrosion and (2) to characterize the composition and structure of bulk surface corrosion films for comparison with ongoing primary water SCC (PWSCC) crack tip corrosion film analyses. Results suggest that the thermal activation energy of Alloy 600 corrosion is consistent with the thermal activation energy of nickel alloy PWSCC. Analytical investigations of the structure and composition of Alloy 600 bulk surface corrosion oxides revealed a duplex (inner and outer) oxide layer structure. The outer layer is discontinuous and comprised of relatively large (1 to 3more » {micro}m) nickel ferrite crystals and smaller ({approx}0.1 {micro}m) chromium containing nickel ferrite crystals. The inner layer consists of a relatively continuous chromite spinel (major phase) and chromia (Cr{sub 2}O{sub 3} minor phase) which formed through non-selective oxidation. Chromia and dealloyed Alloy 600 (highly Ni enriched metal) were only observed at 337 C (640 F) and only along the boundaries of deformation induced fine grains and subcells. Specimens having deformation free surfaces exhibited continuous uniform inner chromite spinel oxide layers. Specimens with machining induced surface deformation produced non-uniform inner layer oxides (chromite spinel, Cr{sub 2}O{sub 3} and unoxidized material). PWSCC crack tip oxides, in contrast, were fine grain (no duplex structure) and consisted of both chromium rich spinels and ''NiO'' structure oxides. Generally, nickel rich oxides were more abundant under more oxidized conditions (reduced coolant hydrogen) and spinel rich crack tip oxides were favored under more reducing conditions (increased coolant hydrogen). Bulk surface corrosion film thickness did not correlate with observed SCC growth rates. These results suggest that corrosion is not the rate controlling step of PWSCC but rather that PWSCC and corrosion have a common rate controlling sub process (e.g., cation diffusion, oxygen ingress).« less
  • In this research program three line pipe steels, removed from long-term service, were examined to determine if there is a correlation between their mechanical properties and stress-corrosion cracking resistance. The hypothesis was that the steel with the greatest tendency for strain hardening, under cyclic and monotonic stress conditions would also have the highest threshold stress for stress-corrosion crack initiation. This hypothesis was verified by the laboratory experiments, which showed the steel with the greatest tendency for strain hardening to have the highest resistance to stress-corrosion. Two other steels, with distinctly lower resistance to plastic deformation, had lower threshold stresses formore » stress-corrosion. This observation is consistent with the present concept of stress-corrosion crack growth, which holds that crack tip dissolution, and hence crack propagation, occurs because localized plastic deformation ruptures passive films or prevents film formation resulting in crack growth. 2 refs., 9 figs., 2 tabs.« less
  • A series of five tests was conducted at the Westinghouse Forest Hills Single Tube Model Boiler (STMB) Facility under this project. The objective of the project was to determine if alkaline earth carbonates and/or hydroxides are key ingreidents in causing intergranular attack (IGA) or stress corrosion cracking (SCC) of mill-annealed Alloy 600. Also as part of this program a report was written and issued detailing the earlier related STMB work Westinghouse conducted that led to reproducible SCC. The work reported here was an extension of that work.
  • The functional requirements of Drivers for the CAMAC Serial Highway defined in IEEE Standard 595-1976 are described. The description is independent of the implementation, and in particular no assumption is made about the boundary between hardware and software within the Driver. Topics covered are the user interface, the supporting system services required, demand handling, and a detailed discussion of the message analysis for various levels of error recovery. An appendix describes the recommended features of LAM Graders for use with the Serial Crate Controller Type L2 of IEEE Std 595-1976.