Analysis of the failure of nuclear reactor pressure vessel closure studs

Conference · Mon Jan 01 04:00:00 EST 1973

OSTI ID:4428446

Burghard, Jr, H C; Pickett, A G

From 2nd international congress for pressure vessel and piping technology; San Antonio, Texas, USA (1 Oct 1973). See CONF-731003-P1. Two A- 437 B4B closure studs of a nuclear reactor pressure vessel failed during the head removal operation. The service history of the vessel and the results of an in- depth investigation of the failure are reviewed. It was determined that the failures occurred by brittle fracture initiated at stress corrosion cracks. Subcritical crack growth was attributed to exposure to an aqueous environment while under load during outage. It was also demonstrated that the fracture toughness of the stud material was inadequate for the intended service. The stress corrosion susceptibiliiy and low toughness of the material are attributed to unsatisfactory heat treatment procedures whose effect may not be detectable by the specified quality control tests. The basis for specifications for replacement stud material and recommended modifications of the in-service inspection program are presented. (auth)

• Research Organization: Southwest Research Inst., San Antonio
• NSA Number: NSA-29-001987
• OSTI ID: 4428446
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

*LACBWR REACTOR-- PRESSURE VESSELS
*PRESSURE VESSELS-- FASTENERS
CLOSURES
CRACKS
FAILURES
FRACTURE PROPERTIES
HEAT TREATMENTS
INSPECTION
N77100* --Reactors--Power Reactors
Non-breeding
Light- water Moderated
Boiling Water-cooled
STRESS CORROSION