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Title: Supplementary safety system corrosion studies

Technical Report ·
DOI:https://doi.org/10.2172/7050612· OSTI ID:7050612

This memorandum presents experimental data from electrochemical and immersion tests to support the continued use of two sections of nonconforming steel in the Supplementary Safety System. The Reactor Corrosion Mitigation Committee met on May 16, 1991 to evaluate materials that had been installed in the SSS. The materials lacked complete Corrosion Evaluation (CE) and/or Certified Mill Test Reports and had been installed during recent modifications (Project S-4332). Items that lacked proper documentation included AISI Type 304 stainless steel (304) instrument tubing (0.375'' OD) associated with the pressure transmitters and a two-foot section of 304 pipe located on the far side of the system downstream of the pneumatic valves. Cyclic potentiodynamic polarization scans were performed on sensitized and solution-annealed 304 samples in as-mixed and acidified Gd(NO{sub 3}){sub 3}, or ink'', solutions at room temperature to determine the susceptibility of 304 to localized corrosion in this environment. No localized attack was observed on the solution annealed or sensitized 304 in the Gd(NO{sub 3}){sub 3} solution. These tests revealed no significant differences in the behavior of the sensitized and solution-annealed 304 in gadolinium nitrate solution. Therefore, localized corrosion of the nonconforming components is not anticipated, and the performance of the nonconforming components should not differ from that of corrosion evaluated and certified materials. Previous studies have shown that AISI Type 304L stainless steel (304L) did not pit during a three-month exposure in gadolinium nitrate solutions of pH 2 or 5. These combined results support the continued use of the nonconforming steels until replacement can be made at the next scheduled long shut-down.

Research Organization:
Savannah River Site (SRS), Aiken, SC (United States)
Sponsoring Organization:
USDOE; USDOE, Washington, DC (United States)
DOE Contract Number:
AC09-89SR18035
OSTI ID:
7050612
Report Number(s):
WSRC-TR-91-389; SRL-MTS-913001; ON: DE92018365
Country of Publication:
United States
Language:
English