Nondestructive evaluation of irradiated pressure vessel steels using positron annihilation lifetime spectroscopy

Book · Sat Dec 31 04:00:00 EST 1994

OSTI ID:72625

Freyer, P D ^[1]; Drinon, D S; Rishel, R D ^[2]

---

1. Pennsylvania State Univ., University Park, PA (United States). Dept. of Materials Science and Engineering
2. Westinghouse Nuclear and Advanced Technology Div., Pittsburgh, PA (United States)

Nuclear reactor pressure vessels have been widely constructed using quenched and tempered A302B, modified A302B, and A533B ferritic steels. The effects of neutron irradiation on the macroscopic properties of these pressure vessel steels have been studied in depth. However, due to the material`s complex microstructures and the very small size of neutron irradiation-induced defects, the microstructural degradation mechanisms associated with neutron bombardment are not well understood. In this study, a nondestructive microstructural evaluation technique known as positron annihilation lifetime spectroscopy (PALS) has been used to investigate the effects of higher energy neutron bombardment on the microstructure of A302B (modified) and A533B ferritic pressure vessel steel. Unirradiated and irradiated samples were studied using, general characterization techniques such as light microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) to determine if neutron-induced defects were resolvable. Unirradiated, irradiated, and annealed material was also analyzed using PALS where it was possible to resolve a third and new lifetime component for the irradiated A302B material suggesting the presence of neutron-induced defects. For highly activated samples, it was not possible to obtain accurate positron lifetime data using the current PALS equipment. However, the PALS technique was capable of discriminating between annealed and unannealed (unirradiated) material. The ability of the PALS technique to measure these defects demonstrates the sensitivity of the technique to detect microstructural changes which cannot be detected using more conventional characterization techniques such as light microscopy, SEM, and TEM.

• OSTI ID: 72625
• Report Number(s): CONF-931061--; ISBN 0-87170-506-0
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
36 MATERIALS SCIENCE
CRYSTAL DEFECTS
EXPERIMENTAL DATA
FERRITIC STEELS
NONDESTRUCTIVE TESTING
NUCLEAR POWER PLANTS
PHYSICAL RADIATION EFFECTS
PRESSURE VESSELS
STEEL-ASTM-A533-B