Evaluation of on-line chelant addition to PWR steam generators. Steam generator cleaning project

Technical Report · Thu Sep 01 04:00:00 EDT 1983

DOI:https://doi.org/10.2172/6862613· OSTI ID:6862613

Tvedt, T. J.; Wallace, S. L.; Griffin, F. Jr.

The investigation of chelating agents for continuous water treatment of secondary loops of PWR steam generators were conducted in two general areas: the study of the chemistry of chelating agents and the study of materials compatability with chelating agents. The thermostability of both EDTA and HEDTA metal chelates in All Volatile Treatment (AVT) water chemistry were shown to be greater than or equal to the 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 study and from the 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 was transported through and cleaned from the MSG's. The Inconel 600 tubes of the salt water fouled model steam generators experienced pitting corrosion. Results of this study demonstrates the feasibility of EDTA as an on-line water treatment additive to maintain nuclear steam generators in a clean condition.

• Research Organization: Dow Chemical Co., Freeport, TX (USA)
• DOE Contract Number: AC02-79ET34015
• OSTI ID: 6862613
• Report Number(s): DOE/ET/34015-7; ON: DE84008859
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
210200* -- Power Reactors
Nonbreeding
Light-Water Moderated
Nonboiling Water Cooled
ALLOYS
AMINO ACIDS
BOILERS
CARBOXYLIC ACIDS
CHELATES
CHELATING AGENTS
CHEMICAL REACTIONS
CHROMIUM ALLOYS
COMPLEXES
CORROSION
CORROSION PRODUCTS
EDTA
FOULING
HEDTA
HYDROXY ACIDS
INCONEL 600
INCONEL ALLOYS
IRON ALLOYS
NICKEL ALLOYS
NICKEL BASE ALLOYS
NIOBIUM ALLOYS
ORGANIC ACIDS
ORGANIC COMPOUNDS
PASSIVATION
PITTING CORROSION
PWR TYPE REACTORS
REACTORS
REMOVAL
STABILITY
STEAM GENERATORS
TUBES
VAPOR GENERATORS
WATER COOLED REACTORS
WATER MODERATED REACTORS