Analysis of iodine stress corrosion cracking of Zircaloy-4 tubing

Technical Report · Sun Feb 01 04:00:00 EST 1976

OSTI ID:4017990

Kreyns, P H; Spahr, G L; McCauley, J E

A fracture mechanics approach to interpreting iodine-vapor stress- corrosion cracking (SCC) in unirradiated Zircaloy-4 tubing is presented in which crack velocities are related to the fourth power on the stress intensity factor, K/sub I/. The crack growth power law on K/sub I/ is shown to predict well the time-to-failure in internally pressurized Zircaloy-4 tubing at 360 and 400$sup 0$C reported by Busby, Tucker and McCauley. The temperature dependency on iodine stress corrosion cracking in Zircaloy can be described by an Arrhenius-type equation in which the activation energy Q for recrystallized and cold-reduced Zircaloy was determined to be 42.9 kcal/mole and 35.9 kcal/mole, respectively. It is concluded that the geometry of the initial surface flaw, through its attendant elastic stress field, is directly responsible in controlling the SCC time-to-failure, cold working having a relatively small effect on increasing the susceptibility to SCC. Any effects of the fast neutron flux on iodine stress corrosion cracking of Zircaloy-4 tubing either in-reactor or out-of-pile are still unknown.

• Research Organization: Bettis Atomic Power Lab., West Mifflin, Pa. (USA)
• NSA Number: NSA-33-026510
• OSTI ID: 4017990
• Report Number(s): WAPD-TM--1203
• Country of Publication: United States
• Language: English

Related Subjects

*IODINE-- CORROSIVE EFFECTS
*ZIRCALOY 4-- STRESS CORROSION
360105* --Materials--Metals & Alloys--Corrosion & Erosion
ACTIVATION ENERGY
CRACKS
FAILURES
FRACTURE PROPERTIES
GEOMETRY
HIGH TEMPERATURE
N50210* --Metals
Ceramics
& Other Materials--Metals & Alloys--Corrosion & Erosion & Surface Phenomena
TIME DEPENDENCE
TUBES
VAPORS