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Title: Investigation of on-line chelant addition to PWR steam generators. Annual report, 1981

Technical Report ·
OSTI ID:6871699

The thermostability of both ethylenediaminetetraacetic acid (EDTA) and hydroxyethylethylenediamininetriacetic acid (HEDTA) metal chelates in all volatile treatment water chemistry (AVT) was shown to be greater than or equal to thermostability of EDTA metal chelates in phosphate-sulfite water chemistry. HEDTA metal chelates were shown to have a much greater stability than EDTA metal chelates. Using samples taken from the EDTA metal chelate thermostability studies and samples from Commonwealth Research Corporation (CRC) model steam generators (MSG), EDTA decomposition products were determined. Active metal surfaces were shown to become passivated when exposed to EDTA and HEDTA concentrations as high as 0.1% w/w in AVT. Trace amounts of iron in the water were found to increase the rate of passivation. Material balance and visual inspection data from CRC model steam generators showed that metal is being transported through and cleaning from the MSG's. EDTA metal chelates were removed from chelate solutions by passing the solutions over strong anion exchange resins.

Research Organization:
Dow Chemical U.S.A., Freeport, TX. Texas Div.
DOE Contract Number:
AC02-79ET34015
OSTI ID:
6871699
Report Number(s):
DOE/ET/34015-4; ON: DE83004803
Country of Publication:
United States
Language:
English