scholarly journals Boron concentration gradient for improved thermal reactor performance of boron-stainless steel control rods

1973 ◽  
Author(s):  
R.J. Beaver ◽  
A.E. Richt
Keyword(s):  
Stainless Steel ◽  
Concentration Gradient ◽  
Boron Concentration ◽  
Thermal Reactor ◽  
Reactor Performance ◽  
Control Rods

Limiting Factors on Steady-State Thermal Reactor Performance

1973 ◽  
Author(s):  
Robert H. Kadlec ◽  
Everett A. Sondreal ◽  
Donald J. Patterson ◽  
Marshall W. Graves
Keyword(s):  
Steady State ◽  
Limiting Factors ◽  
Thermal Reactor ◽  
Reactor Performance

scholarly journals Boron concentration gradient in the endosperm and embryo during ovule development in Clivia miniata

2014 ◽  
Vol 65 (1-2) ◽  
pp. 147-150
Author(s):  
Witold Reczyński ◽  
Marian Ryczkowski ◽  
Urszula Czaja
Keyword(s):  
Concentration Gradient ◽  
Boron Concentration ◽  
Chemical Compounds ◽  
Exponential Phase ◽  
Ovule Development ◽  
Clivia Miniata ◽  
Polar Distribution

Research on boron concentration gradient in the endosperm and embryo of <em>Clivia miniata</em> Regel ovules is a continuation of investigations on polar distribution of several compounds in the developing ovule. The polar distribution of chemical compounds in the ovule might constitute one of the factors determining embryogenesis. It was found that: a) there occured a chalaza-micropyle gradient of boron concentration in the endosperm during the exponential phase of embryo growth (age of ovules - 50 to 120 days); boron concentration in the endosperm increased from 12.13 to 23.71 µg g<sup>-1</sup> fr.wt. (micropylar part) and from 13.58 to 28.42 µg g<sup>-1</sup> fr.wt. (chalazal part); the embryo elongated towards the chalazal part of the ovule, i.e. towards higher boron concentration in the endosperm; b) in the embryo a reversed gradient of boron was detected: a higher concentration in the micropylar part (decrease from 127.29 to 61.78 µg g<sup>-1</sup> fr.wt.; ovules 86-123 days old), a lower one in the chalazal part (decrease from 99.47 to 53.16 µg g<sup>-1</sup> fr.wt.; the exponential phase of embryo growth).

Structural integrity assessment and lifetime prediction for the control rods couplings of the WWER-440 reactor. Part 3. Optimi- zation of post-irradiation recovery annealing of the control rods couplings

2021 ◽  
pp. 177-191
Author(s):  
A. J. Minkin ◽  
B. Z. Margolin ◽  
L. A. Belyaeva ◽  
N. E. Pirogova ◽  
A. M. Shumko ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Structural Integrity ◽  
Complete Recovery ◽  
Steel 08Kh18n10t ◽  
Control Rod ◽  
Integrity Assessment ◽  
Post Irradiation ◽  
Recovery Annealing ◽  
Aisi 321 ◽  
Control Rods

The optimization of post-irradiation recovery annealing of metal of control rods couplings (marten- sitic-ferritic stainless steel 14Kh17N2 grade, analogue of AISI 431 steel) is carried out. It is shown that the optimized recovery annealing leads to complete recovery of the mechanical properties of coupling metal embrittled under neutron irradiation. The recovery annealing does not reduce corrosion resistance of control rod tube made of austenitic stainless steel 08Kh18N10T grade (analogue of AISI 321 steel).

scholarly journals Flattening of the Power Distribution in the HTGR Core with Structured Control Rods

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7377
Author(s):  
Michał Górkiewicz ◽  
Jerzy Cetnar
Keyword(s):  
Power Distribution ◽  
Reactor Core ◽  
Reactor Performance ◽  
Fission Rate ◽  
Control Rod ◽  
Structured Design ◽  
The Core ◽  
Stable Core ◽  
Control Rods ◽  
Burnup Calculation

Control rods (CRs) have a significant influence on reactor performance. Withdrawal of a control rod leaves a region of the core significantly changed due to lack of absorber, leading to increased fission rate and later to Xe135 buildup. In this paper, an innovative concept of structured control rods made of tungsten is studied. It is demonstrated that the radial division of control rods made of tungsten can effectively compensate for the reactivity loss during the irradiation cycle of high-temperature gas-cooled reactors (HTGRs) with a prismatic core while flattening the core power distribution. Implementation of the radial division of control rods enables an operator to reduce this effect in terms of axial power because the absorber is not completely removed from a reactor region, but its amount is reduced. The results obtained from the characteristic evolution of the reactor core for CRs with a structured design in the burnup calculation using the refined timestep scheme show a very stable core evolution with a reasonably low deviation of the power density and Xe135 concentration from the average values. It is very important that all the distributions improve with burnup.

Structural integrity assessment and lifetime prediction for the control rods couplings of the WWER-440 reactor. Part 2. Assessment of the coupling structural integrity and justification of its material degradation monitoring interval

2021 ◽  
pp. 163-176
Author(s):  
A. J. Minkin ◽  
B. Z. Margolin ◽  
V. G. Fedosov
Keyword(s):  
Stainless Steel ◽  
Vickers Hardness ◽  
Structural Integrity ◽  
Steel Grade ◽  
Material Degradation ◽  
Control Rod ◽  
Integrity Assessment ◽  
Degradation Monitoring ◽  
Radiation Induced ◽  
Control Rods

The structural integrity of the control rods couplings of the WWER-440 reactor is analyzed. On the basis of material investigation of the control rod couplings (martensitic-ferritic stainless steel grade 14Kh17N2, analogue of AISI 431 steel) that were under operation in the Unit 3 of Novovoronezh NPP it is shown that the structural integrity of the coupling is satisfied until the radiation-induced hardening of its material does not exceed 423 units of Vickers hardness.

Study on Eutectic Melting Behavior of Control Rod Materials in Core Disruptive Accidents of Sodium-Cooled Fast Reactors: Validation of a Multi-Phase Model for Eutectic Reaction Between Stainless Steel and Boron Carbide

2020 ◽  
Author(s):  
Xiaoxing Liu ◽  
Koji Morita ◽  
Hidemasa Yamano
Keyword(s):  
Stainless Steel ◽  
Eutectic Composition ◽  
Boron Concentration ◽  
Eutectic Reaction ◽  
Three Dimensional ◽  
Melting Behavior ◽  
Reaction Model ◽  
Eutectic Melting ◽  
Control Rod ◽  
Liquid Phases

Abstract Investigation of the eutectic reaction in a core disruptive accident of sodium cooled reactor is of importance since reactor criticality will be affected by the change in reactivity after eutectic reaction. In our previous study, a two-dimensional fast reactor safety analysis code, SIMMER-III, was extended to include a physical model to simulate the eutectic reaction between stainless steel (SS) and B4C. Based on experimental knowledge on eutectic reaction, the growth of eutectic material was modeled according to a parabolic rate law. Heat and mass transfer behaviors among reactor materials including a eutectic composition in solid and liquid phases were also modeled considering both equilibrium and non-equilibrium processes in phase change. Physical properties of the eutectic composition were also formulated based on experimental measurements for 5 mass% B4C-SS composition. In this study, we extended the eutectic reaction model to SIMMER-IV, a three-dimensional counterpart of SIMMER-III. We performed validation analysis using SIMMER-III and SIMMER-IV with the developed model based on an experiment, where a B4C pellet was immersed into a molten SS pool. Boron concentration in the pool was measured at several time points and the boron concentration after solidification of the molten pool was compared with the experiment post analysis result. Simulation results of boron distribution are comparable to the experimental results.

Sign in / Sign up

Export Citation Format

Share Document