scholarly journals Brittle fracture resistance of reactor pressure vessel steels in the initial state

2018 ◽  
Vol 4 (3) ◽  
pp. 155-161
Author(s):  
Yegor Pogorelov ◽  
Nikolay Anosov ◽  
Vladimir Skorobogatykh ◽  
Lyubov Gordyuk ◽  
Vasiliy Mikheev ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Transition Temperature ◽  
Brittle Fracture ◽  
Fracture Resistance ◽  
Critical Brittleness Temperature ◽  
Initial State ◽  
Brittleness Temperature ◽  
Brittle Fracture Resistance ◽  
The Difference ◽  
Upper Level

The authors investigate the influence of chemical and structural inhomogeneity on the brittle fracture resistance (BFR) of VVER vessel materials in the initial state (without irradiation). It is proposed to replace the brittle fracture resistance assessment using the critical brittleness temperature TC for the BFR assessment using the brittle-viscous transition temperature TT. Consideration was given to calibration charts used for studying the TT dependence on the grain size and heat treatment. A comparison of the TC and TT values in the experimental industrial 15H2NMFA-A steel billets shows that the TC values are significantly lower than the TT values: – at the lower level of conservatism, the difference between TC and TT is 22 °C; – at the upper level of conservatism, this difference is 24 °C. The array data on the critical brittleness temperature and the ductile-to-brittle transition temperature of impact test samples of 15H2NMFAA (for VVER-1000) and 15H2NMFA grade 1 (for VVER-1200) steels were statistically processed. The industrial shell samples were manufactured at the “Energomashspetsstal” plant (Kramatorsk, Ukraine). It was found that, in the metal of VVER-1000 vessel surveillance specimens with the copper content – less than 0.06%, heat treatment has a significant effect on the TT value, which changes from –99 to –28°C; – from 0.07 to 0.12%, heat treatment has a significant effect on the TT value, which changes from –60 to –40°C.

Conservative estimations of irradiation embrittlement of reactor pressure vessel steels for WWER-1000 lifetime prediction

2019 ◽  
Vol 15 (1) ◽  
pp. 246-257
Author(s):  
Nikolai Petrovich Anosov ◽  
Vladimir Nikolaevich Skorobogatykh ◽  
Lyubov’ Yur’yevna Gordyuk ◽  
Vasilii Anatol’evich Mikheev ◽  
Egor Vasil’yevich Pogorelov ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Brittle Fracture ◽  
Pressure Vessel ◽  
Reactor Pressure Vessel ◽  
Lifetime Prediction ◽  
Critical Brittleness Temperature ◽  
Irradiation Embrittlement ◽  
Content Type ◽  
Brittleness Temperature ◽  
Reactor Pressure

Purpose The purpose of this paper is to consider a procedure of water-water energetic reactor (WWER) reactor pressure vessel (RPV) lifetime prediction at the stages of design and lifetime extension using the standard irradiation embrittlement parameters as defined in regulatory documents. A comparison is made of the brittle fracture resistance (BFR) values evaluated using two criteria: shift in the critical brittleness temperature ΔTc or shift in the brittle-to-ductile transition temperature ΔTp and without shifts (Tc and Tp). Design/methodology/approach The radiation resistance was determined using the following three approaches: calculation based on standard values ΔTc and Tc0 or ΔTp and Tp0 (a level of excessive conservatism); calculation based on standard value ΔTc and actual value Tc0 or actual values ΔTp and Tp0 (the level of realistic conservatism); or calculation based on actual values of Tc and Tc0 or Tp and Tp0 (the level of actual conservatism). The BFR was evaluated based on the results of testing the specimens subjected to irradiation in research reactors as well as surveillance specimens subjected to irradiation immediately under operating conditions. Findings The excessive conservatism in determining the actual lifetime of nuclear reactor vessel materials can be eliminated by using the immediate values of critical brittleness temperature and ductile-to-brittle transition temperature. Originality/value Obtained results can be applied to extend WWER vessel operating time at the stages of designing and operation due to substantiated decrease in conservatism. And it will allow carrying out a statistical substantiated assessment of the resistance to brittle fracture of the RPV steels.

scholarly journals Brittle fracture resistance of reactor pressure vessel steels in the initial state

2018 ◽  
Vol 2018 (1) ◽  
pp. 134-145
Author(s):  
Nikolay Petrovich Anosov ◽  
Vladimir Nikolaevich Skorobogatykh ◽  
Lyubov’ Yur’yevna Gordyuk ◽  
Vasiliy Anatol’yevich Mikheev ◽  
Egor Vasil’yevich Pogorelov ◽  
...  
Keyword(s):  
Brittle Fracture ◽  
Pressure Vessel ◽  
Fracture Resistance ◽  
Reactor Pressure Vessel ◽  
Initial State ◽  
Brittle Fracture Resistance ◽  
Pressure Vessel Steels ◽  
Reactor Pressure

scholarly journals Inclusion of Warm Pre-Stress Concept in French RPV Structural Integrity Assessment

2016 ◽  
Author(s):  
Dominique Moinereau ◽  
Malik Ait-Bachir ◽  
Stéphane Chapuliot ◽  
Stéphane Marie ◽  
Clémentine Jacquemoud ◽  
...  
Keyword(s):  
Brittle Fracture ◽  
Fracture Resistance ◽  
Large Scale ◽  
Structural Integrity ◽  
Stress Effect ◽  
Local Approach ◽  
Experimental Database ◽  
Term Operation ◽  
Integrity Assessment ◽  
Brittle Fracture Resistance

Evaluation of the fracture resistance of nuclear reactor pressure vessel (RPV) regarding the risk of brittle fracture is a key point in the structural integrity assessment of the component (RPV). Such approach is codified in French RSE-M code, based on a very conservative methodology. With respect to long term operation, an improvement of the present methodology is necessary and in progress to reduce this conservatism. One possible significant improvement is the inclusion of the warm pre-stress (WPS) concept in the assessment. After a short description of the WPS concept, the process engaged in France to allow inclusion of WPS in the integrity assessment is presented. In a first step, experimental and numerical studies have been conducted in France by EDF, CEA and AREVA (also including international collaborations and projects) to demonstrate and validate the beneficial effect of WPS on the brittle fracture resistance of RPV steels. A large panel of experimental results and data is now available obtained on small, medium and large scale specimens on representative RPV steels (including highly irradiated RPV materials). These data have been included in a specific WPS experimental database. Main experiments have been interpreted by refined computations, based on elastic plastic analyses and local approach to cleavage fracture. In a second step, a new criterion (ACE criterion) has been proposed by French organizations (AREVA, CEA and EDF) for an easy simplified evaluation of warm pre-stress effect on the brittle fracture resistance of RPV steels. Accuracy and conservatism of the criterion is verified by comparison to experimental data results and numerical analyses. Finally, implementation of the WPS effect in the French RSE-M code (for in service assessment) is in progress, based on the ACE criterion. The present paper summarizes all these steps leading to codification of WPS in RSE-M code.

Effect of transient heating of the outer surface of a radial crack-containing ring specimen on its brittle fracture resistance

2012 ◽  
Vol 44 (4) ◽  
pp. 429-437 ◽  
Author(s):  
G. V. Stepanov ◽  
V. V. Kharchenko ◽  
A. A. Kotlyarenko ◽  
A. I. Babutskii ◽  
V. N. Zhmaka
Keyword(s):  
Brittle Fracture ◽  
Outer Surface ◽  
Fracture Resistance ◽  
Radial Crack ◽  
Ring Specimen ◽  
Transient Heating ◽  
Brittle Fracture Resistance

Al2O3-Based Ceramic Composites with a High Brittle Fracture Resistance

2019 ◽  
Vol 55 (6) ◽  
pp. 628-633 ◽  
Author(s):  
L. I. Podzorova ◽  
A. A. Il’icheva ◽  
O. I. Pen’kova ◽  
O. S. Antonova ◽  
A. S. Baikin ◽  
...  
Keyword(s):  
Brittle Fracture ◽  
Fracture Resistance ◽  
Ceramic Composites ◽  
Brittle Fracture Resistance
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