Characteristics of autoclave and in-reactor nodular corrosion of Zircaloys

Conference · Thu Nov 01 04:00:00 EST 1990

OSTI ID:5769450

Jeong, Y H; Rheem, K S ^[1]; Chung, H M ^[2]

---

1. Korea Atomic Energy Research Inst., Daeduk (Republic of Korea)
2. Argonne National Lab., IL (USA)

Nodular corrosion characteristics of recrystallized Zircaloy-4 were investigated in static autoclave tests at 500{degree}C and 10.3 MPa. The roles of annealing temperature, cooling rate after beta-treating at 1050{degree}C, cold work, and surface treatment in corrosion tests were correlated with the results of microstructural characterization by scanning and transmission electron microscopies. A good correlation was obtained between average size of intermetallic precipitates and weight gain, in contrast to nodule coverage and nodule number density. These results could be best explained by the hypothesis that nodules nucleate in local regions that are depleted of Fe and Cr alloying elements. Some observations were inconsistent with the premise that nodules nucleate on or near intermetallic precipitates. Nodular corrosion characteristics and microstructures of commercial Zircaloy-2 cladding of fuel and gadolinia rods, obtained from several BWRs after burnup of 11--30 MWd/kgU, were also examined. Partial amorphization of intermetallic precipitates in BWR Zircaloy-2, and virtual dissolution and in an extreme case spinodal- like fluctuations of dissolved alloying elements in PWR Zircaloy-4 cladding were observed. Occurrence of nodular oxidation of Zircaloy-2 in BWRs could best be correlated to average size of intermetallic precipitates before irradiation and to fuel cladding operating temperature. For an intermetallic size range of 250--700 nm, nodular oxides were observed at 288{degree}C, but only thick uniform oxide was observed at 307{degree}C. 53 refs., 14 figs., 1 tab.

• Research Organization: Argonne National Lab., IL (USA)
• Sponsoring Organization: DOE; USDOE, Washington, DC (USA)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5769450
• Report Number(s): ANL/CP-69633; CONF-901107--1; ON: DE91013600
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
210100* -- Power Reactors
Nonbreeding
Light-Water Moderated
Boiling Water Cooled
36 MATERIALS SCIENCE
360105 -- Metals & Alloys-- Corrosion & Erosion
360106 -- Metals & Alloys-- Radiation Effects
ALLOY-ZR98SN-4
ALLOYS
ANNEALING
AUTOCLAVES
BWR TYPE REACTORS
CHEMICAL REACTIONS
CHROMIUM ADDITIONS
CHROMIUM ALLOYS
COLD WORKING
CORROSION
CORROSION RESISTANT ALLOYS
CRYSTAL STRUCTURE
FABRICATION
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
HEAT TREATMENTS
INTERMETALLIC COMPOUNDS
IRON ADDITIONS
IRON ALLOYS
IRRADIATION
MATERIALS
MATERIALS WORKING
MICROSTRUCTURE
NIOBIUM ALLOYS
OXIDATION
PHYSICAL RADIATION EFFECTS
PWR TYPE REACTORS
RADIATION EFFECTS
REACTORS
SURFACE TREATMENTS
TIN ALLOYS
WATER COOLED REACTORS
WATER MODERATED REACTORS
ZIRCALOY
ZIRCALOY 4
ZIRCONIUM ALLOYS
ZIRCONIUM BASE ALLOYS