Determination of the Fracture Toughness of Irradiated Reactor Pressure Tubes Using Curved Compact Specimens

2009 ◽  
pp. 419-419-21 ◽  
Author(s):  
CK (Peter) Chow ◽  
LA Simpson
Keyword(s):  
Fracture Toughness ◽  
Pressure Tubes ◽  
Reactor Pressure

Preliminary Results On Ultrasonic Attenuation Detection Of Neutron Irradiation Embrittlement Of Nuclear Reactor Steel

1997 ◽  
Vol 503 ◽  
Author(s):  
A. L. Hiser ◽  
R. E. Green
Keyword(s):  
Fracture Toughness ◽  
Neutron Irradiation ◽  
Pressure Vessel ◽  
Ultrasonic Attenuation ◽  
Reactor Pressure Vessel ◽  
Irradiation Embrittlement ◽  
Preliminary Results ◽  
Nondestructive Determination ◽  
Reactor Pressure

ABSTRACTNeutron bombardment of reactor pressure vessel (RPV) steels causes reductions in fracture toughness in these steels, termed neutron irradiation embrittlement. Currently there are no accepted methods for nondestructive determination of the extent of the irradiation embrittlement nor the actual fracture toughness of the reactor pressure vessel. This paper provides preliminary results of an effort addressing the use of ultrasonic attenuation as a suitable parameter for nondestructive determination of irradiation embrittlement in RPV steels.

To Determination of the WWER RPV Steels Crack Resistance Characteristics

2013 ◽  
Author(s):  
Igor Orynyak ◽  
Maksym Zarazovskii ◽  
Sergii Radchenko ◽  
Volodymyr Kozlov
Keyword(s):  
Fracture Toughness ◽  
Transition Temperature ◽  
Crack Resistance ◽  
Temperature Shift ◽  
Charpy Impact ◽  
Temperature Range ◽  
Pressurized Thermal Shock ◽  
Reactor Pressure ◽  
15Kh2nmfa Steel

The efficiency of fracture toughness determined by the methodology of normative document PNAE G-7-002-86 has been analyzed. Crack resistance characteristics of WWER-1000 reactor pressure vessel base metal at unirradiated condition are obtained by experimental way. All specimens were made of the RPV support forging (15Kh2NMFA steel) of abandoned Crimean NPP Fracture toughness experiments were carried out on three types of specimens CT 1T, CT 0.5T and SEB over a temperature range from −130°C to −40°C in fully accordance to the ASTM E1921. Charpy impact energy data obtained on twelve specimens over a temperature range from −80°C to 80°C has been used to determine the 47J transition temperature. Comparison of obtained fracture toughness data with normative curve shows that the last one has unreasonably high lower shelf. It has been found that the PNAE G-7-002-86 Code, which uses the ideology of transition temperature shift, is too conservative to estimate WWER-1000 RPVs resistance against brittle fracture for the pressurized thermal shock (over 90 MPa·√m area of stress intensity factor).

Rational Determination of Lower-Bound Fracture Toughness Curves Using Master Curve Approach

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Naoki Miura ◽  
Naoki Soneda ◽  
Shu Sawai ◽  
Shinsuke Sakai
Keyword(s):  
Fracture Toughness ◽  
Lower Bound ◽  
Master Curve ◽  
Surveillance Program ◽  
Data Sets ◽  
Ductile Brittle Transition Temperature ◽  
Asme Code ◽  
American Society ◽  
Reactor Pressure

The Master Curve gives the relation between the median of fracture toughness of ferritic steels and the temperature in the ductile–brittle transition temperature region. The procedure used to determine the Master Curve is provided in the current American Society for Testing and Materials (ASTM) E1921 standard. By considering the substitution of the alternative lower-bound curves based on the Master Curve approach for the KIc curves based on reference data sets in the present codes such as ASME Code Cases N-629 and N-631, the statistical characteristic should be well incorporated in the determination of the lower-bound curves. Appendix X4 in the ASTM standard describes the procedure used to derive the lower-bound curves; however, it appears to be addressed without sufficient consideration of the statistical reliability. In this study, we propose a rational determination method of lower-bound fracture toughness curves using the Master Curve approach. The method considers the effect of sample size in the determination of the tolerance-bound curve. The adequacy of the proposed method was verified by comparing the tolerance-bound curve with the fracture toughness database for national reactor pressure vessel (RPV) steels including plate and forging obtained from 4 T to 0.4 T C(T) specimens and 0.4 T SE(B) specimens. The method allows the application of the Master Curve using fewer specimens, which can coexist with the present surveillance program.

Alternative Reference Temperature Based on Master Curve Approach in Japanese Reactor Pressure Vessel Steel

2013 ◽  
Author(s):  
Takatoshi Hirota ◽  
Takashi Hirano ◽  
Kunio Onizawa
Keyword(s):  
Fracture Toughness ◽  
Pressure Vessel ◽  
Master Curve ◽  
Reactor Pressure Vessel ◽  
Test Method ◽  
Reference Temperature ◽  
Ferritic Steels ◽  
Pressure Vessel Steel ◽  
Reactor Pressure

Master Curve approach is the effective method to evaluate the fracture toughness of the ferritic steels accurately and statistically. The Japan Electric Association Code JEAC 4216-2011, “Test Method for Determination of Reference Temperature, To, of Ferritic Steels” was published based on the related standard ASTM E 1921-08 and the results of the investigation of the applicability of the Master Curve approach to Japanese reactor pressure vessel (RPV) steels. The reference temperature, To can be determined in accordance with this code in Japan. In this study, using the existing fracture toughness data of Japanese RPV steels including base metals and weld metals, the method for determination of the alternative reference temperature RTTo based on Master Curve reference temperature To was statistically examined, so that RTTo has an equivalent safety margin to the conventional RTNDT. Through the statistical treatment, the alternative reference temperature RTTo was proposed as the following equation; RTTo = To + CMC + 2σTo. This method is applicable to the Japan Electric Association Code JEAC 4206, “Method of Verification Tests of the Fracture Toughness for Nuclear Power Plant Components” as an option item.

Applicability of Sub-Size Charpy Specimens to Transition Behaviour of RPV Materials

2007 ◽  
Vol 348-349 ◽  
pp. 977-980
Author(s):  
Michal Falcnik ◽  
Petr Novosad ◽  
Pavel Pesek ◽  
Mylos Kytka
Keyword(s):  
Fracture Toughness ◽  
Dynamic Fracture ◽  
Standard Specimen ◽  
Dynamic Fracture Toughness ◽  
Radiation Embrittlement ◽  
Toughness Testing ◽  
Transition Behaviour ◽  
Reactor Pressure ◽  
Selection Of

The advancement of proper methodology to determination of VVER reactor pressure vessel (RPV) materials transition behaviour has been followed. The project included selection of proper specimen geometries (standard 10x10x55 mm, sub-size 3x4x27 mm and 5x5x27.5 mm Charpy-V samples) and impact as well as dynamic fracture toughness testing. All the fundamental criterions have been applied to consider an applicability of small-sized specimens to Cr-Mo-V and Cr-Ni-Mo-V steel radiation embrittlement studies. Selected specimen geometries have been found to be fully valid for impact and dynamic fracture data and capable for prediction of standard specimen behaviour from the small specimens. Within testing of irradiated materials, it has been found not fully validity of all the compared transition temperatures.

Toughness and Embrittlement of RPV Steels Using Ultrasonic Measurements

2004 ◽  
Author(s):  
Allen L. Hiser
Keyword(s):  
Fracture Toughness ◽  
Pressure Vessel ◽  
Ultrasonic Attenuation ◽  
Reactor Pressure Vessel ◽  
Irradiation Embrittlement ◽  
Nondestructive Determination ◽  
Rpv Steel ◽  
Suitable Parameter ◽  
Reactor Pressure

Neutron bombardment of reactor pressure vessel (RPV) steels causes reductions in fracture toughness in these steels, termed neutron irradiation embrittlement. Currently there are no accepted methods for nondestructive determination of the extent of the irradiation embrittlement nor the actual fracture toughness of the reactor pressure vessel. This paper summarizes the findings from an effort addressing the use of ultrasonic attenuation as a suitable parameter for nondestructive determination of irradiation embrittlement in RPV steels. The materials examined in this study include one heat of RPV steel that was heat treated to induce changes in its fracture toughness, several heats of RPV steel irradiated to assess neutron embrittlement changes in fracture toughness, and a matrix of RPV steels (in the unirradiated condition) with a range of as-fabricated fracture toughness levels.

Effect of In-Plane Constraint and Type of Loading on Fracture Toughness of Two RPV Steels of PWRs

2004 ◽  
Author(s):  
D. Lauerova ◽  
M. Brumovsky
Keyword(s):  
Fracture Toughness ◽  
Ferritic Steel ◽  
Aged Condition ◽  
Constraint Effect ◽  
Vessel Material ◽  
Grade 3 ◽  
The Individual ◽  
Reactor Pressure ◽  
Fracture Specimens

In the paper, results obtained from testing of small specimens performed within VOCALIST project at NRI Rez are presented. The VOCALIST project covered examination of constraint effect on fracture toughness for two steels representing materials of reactor pressure vessel: material A, i.e. steel of 22NiMoCr 3 7 type (similar to ASTM A 508 Grade 3 Class I), and material D, i.e. ferritic steel A533B in aged condition. At NRI Rez, a total of 79 small fracture specimens were tested, the specimens contained either shallow or deep cracks, and both tension and bending types of loading were examined. For the individual groups of specimens (bending/tension specimens with deep/shallow cracks from material A/D) Master Curve reference temperatures T0 were determined. For material D, smaller values of T0 for tension than for bending were found, both for deep and shallow cracks. J-Q loci for material A and D for selected temperatures were constructed and are presented in the paper. Also, in connection with construction of J-Q loci, the problems with determination of Q-stress parameter with respect to value of standardized distance rσ0/J are addressed.

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