Fracture Toughness Evaluation of Neutron-Irradiated Reactor Pressure Vessel Steel Using Miniature-C(T) Specimens

2017 ◽  
Author(s):  
Yoosung Ha ◽  
Tohru Tobita ◽  
Hisashi Takamizawa ◽  
Yutaka Nishiyama
Keyword(s):  
Fracture Toughness ◽  
Pressure Vessel ◽  
Reactor Pressure Vessel ◽  
Pressure Vessel Steel ◽  
Vessel Steel ◽  
Reactor Pressure Vessel Steel ◽  
Rpv Steel ◽  
Toughness Evaluation ◽  
Fracture Toughness Evaluation ◽  
Reactor Pressure

The applicability of miniature-C(T) (Mini-C(T)) specimens to fracture toughness evaluation was investigated for neutron-irradiated reactor pressure vessel (RPV) steel. By carefully selecting the test temperature, valid fracture toughness and reference temperature (To) were determined successfully with a relatively small number of specimens. The value of To determined using irradiated Mini-C(T) specimens was in good agreement with that determined using irradiated pre-cracked Charpy-type (PCCv) specimens. In addition, the scatter of the 1T-equivalent fracture toughness values obtained using the irradiated Mini-C(T) specimens was not significantly different from that obtained using the irradiated PCCv and other larger unirradiated specimens. The To values determined using Mini-C(T) specimens agree very well with the correlation between the Charpy 41J transition temperature and the To of commercially manufactured RPV steels reported in the past.

Fracture Toughness Evaluation of Heat-Affected Zone Under Weld Overlay Cladding in Reactor Pressure Vessel Steel

2018 ◽  
Author(s):  
Yoosung Ha ◽  
Tohru Tobita ◽  
Hisashi Takamizawa ◽  
Satoshi Hanawa ◽  
Yutaka Nishiyama
Keyword(s):  
Fracture Toughness ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Pressure Vessel ◽  
Reactor Pressure Vessel ◽  
Pressure Vessel Steel ◽  
Vessel Steel ◽  
Weld Overlay ◽  
Reactor Pressure Vessel Steel ◽  
Reactor Pressure

An evaluation of the fracture toughness of the heat-affected zone (HAZ), which is located under the weld overlay cladding of a reactor pressure vessel (RPV), was performed. Considering inhomogeneous microstructures of the HAZ, 0.4T-C(T) specimens were manufactured from the cladding strips locations, and Mini-C(T) specimens were fabricated from the distanced location as well as under the cladding. The reference temperature (To) of specimens that were aligned with the middle section of a cladding strip (HAZMCS) was ∼12°C higher than that of specimens that were aligned with cladding strips at the overlap (HAZOCS). To values of partial area in the HAZ were obtained using Mini-C(T) specimen. The To values obtained near the side of the cladding were ∼13°C higher than those away from the cladding. To values of HAZ for both 0.4T-C(T) and Mini-C(T) specimens were significantly lower than that of the base metal at a quarter thickness by 40°C–60°C. Compared to the literature data that indicated fracture toughness at the surface without overlay cladding and base metal of a quarter thickness in a pressure vessel plate, this study concluded that the welding thermal history showed no significant effect on the fracture toughness of the inner surface of RPV steel.

Sign in / Sign up

Export Citation Format

Share Document