Abstract
This paper describes numerical analyses performed to
simulate warm pre-stress (WPS) experiments conducted with
large-scale cruciform specimens within the Network for
Evaluation of Structural Components (NESC-VII) project.
NESC-VII is a European cooperative action in support of WPS
application in reactor pressure vessel (RPV) integrity
assessment. The project aims in evaluation of the influence of
WPS when assessing the structural integrity of RPVs.
Advanced fracture mechanics models will be developed and
performed to validate experiments concerning the effect of
different WPS scenarios on RPV components. The Oak Ridge
National Laboratory (ORNL), USA contributes to the Work
Package-2 (Analyses of WPS experiments) within the NESCVII
network.
A series of WPS type experiments on large-scale cruciform
specimens have been conducted at CEA Saclay, France, within
the framework of NESC VII project. This paper first describes
NESC-VII feasibility test analyses conducted at ORNL. Very
good agreement was achieved between AREVA NP SAS and
ORNL. Further analyses were conducted to evaluate the
NESC-VII WPS tests conducted under Load-Cool-Transient-
Fracture (LCTF) and Load-Cool-Fracture (LCF) conditions.
This objective of this work is to provide a definitive
quantification of WPS effects when assessing the structural
integrity of reactor pressure vessels. This information will be
utilized to further validate, refine, and improve the WPS
models that are being used in probabilistic fracture mechanics
computer codes now in use by the NRC staff in their effort to
develop risk-informed updates to Title 10 of the U.S. Code of
Federal Regulations (CFR), Part 50, Appendix G.