Impact of control rod insertion during burnup on PWR fuel assembly isotopic composition

Kerntechnik ◽  
2021 ◽  
Vol 86 (2) ◽  
pp. 173-181
Author(s):  
R. M. Refeat ◽  
H. K. Louis
Keyword(s):  
Safety Analysis ◽  
Second Phase ◽  
Spent Fuel ◽  
Reactor Operation ◽  
Control Rod ◽  
Two Phases ◽  
And Control ◽  
Criticality Analysis ◽  
Control Rods ◽  
Criticality Safety

Abstract Criticality analysis of spent fuel assumes that the fuel material is unburned which means that it is in its most reactive condition. In fact, this is not the real situation for fuel as it is burned during reactor operation causing reduction in the reactivity. Considering the reduction in reactivity during spent fuel calculations is the Burn-up Credit concept (BUC). In addition, the control rods radial and axial positions have an effect on the reactivity which can be considered in the criticality safety analysis. This paper studies the effect of burnup and control rods (CRs) movement on reactivity and isotopes inventory. Calculations are carried out in two phases, first kinf is calculated for different burnup profiles with control rods are either fully withdrawn or fully inserted. In the second phase keff is calculated for different control rods insertion levels. For both phases, burnup calculations are performed for a UO2 assembly then multiplication factor calculations of burned UO2 assemblies in cold state are done. The burnup calculations are performed using MCNP6 code and ENDF/B-VII library for different burnup levels up to 45 GWd/tU. The results obtained can be taken in consideration in criticality safety analysis performed for the spent fuel to improve the economic efficiency for manufacture, storage and transportation of fissile materials.

Axial Burnup Profile Influence on Criticality Safety of WWER Spent Fuel

2006 ◽  
Author(s):  
Surik Bznuni ◽  
Armen Amirjanyan ◽  
Shahen Poghosyan
Keyword(s):  
Safety Assessment ◽  
Safety Analysis ◽  
Spent Fuel ◽  
End Effect ◽  
Oak Ridge ◽  
Fuel Assemblies ◽  
Spent Fuel Storage ◽  
Fuel Storage ◽  
Criticality Analysis ◽  
Criticality Safety

Criticality safety assessment for WWER-440 NUHOMS® cask with spent nuclear fuel from Armenian NPP has been performed. The cask was designed in a such way that the neutron multiplication factor keff must be below 0,95 for all operational modes and accident conditions. Usually for criticality analysis, fresh fuel approach with the highest enrichment is taken as conservative assumption as it was done for ANPP. Nuclear and Radiation Safety Centre of Armenian Nuclear Regulatory Authority (NRSC ANRA) in order to improve future fuel storage efficiency, initiated research with taking into account burn up credit in the criticality safety assessment. Axial burn up profile (end effect) has essential impact on criticality safety justification analysis. However this phenomenon wasn’t taken into account in the Safety Analysis Report of NUHOMS® spent fuel storage constructed on the site of ANPP. Although ANRA doesn’t yet accept burn up credit approach for ANPP spent fuel storage, assessment of impact of axial burn up profile on criticality of spent fuel assemblies has important value for future activities of ANRA. This paper presents results of criticality safety analysis of spent fuel assemblies with axial burn up profile. Horizontal burn up profile isn’t taken account since influence of the horizontal variation of the burn up is much less than the axial variation. The Actinides and Actinides + Fission Products approach are discussed. The calculations were carried out with STARBUCS module of SCALE 5.0 code package developed at Oak Ridge National laboratory. SCALE5.0 sequence CSAS26 (KENO-VI) was used for evaluation the keff for 3-D problems. Obtained results showed that criticality of ANPP spent fuel cask is very sensitive to the end effect. Using Burn up profiles of Control Assemblies in both approaches leads to much more increasing than in case of Working Assemblies. Usually increasing burn up leads to decreasing Δkeff, hence decreasing end effect. However for WWER-440 Control Assemblies that worked only within 6th (operative) group increasing burn up leads to increasing of the end effect.

scholarly journals Bioindicator demonstrates high persistence of sulfentrazone in dry soil1

2015 ◽  
Vol 45 (3) ◽  
pp. 326-332 ◽  
Author(s):  
Renato Coradello Lourenço ◽  
Saul Jorge Pinto de Carvalho
Keyword(s):  
Dose Response ◽  
Residual Effect ◽  
Second Phase ◽  
Response Curves ◽  
Sugarcane Crop ◽  
Phytotoxic Activity ◽  
Dry Soil ◽  
Two Phases ◽  
Preemergence Herbicides ◽  
And Control

ABSTRACTIn sugarcane crop areas, the application of preemergence herbicides with long residual effect in the soil has been frequently necessary. The herbicide persistence in the soil must be high especially because of applications during the dry season of the year, after sugarcane harvest. This study aimed at estimating the sulfentrazone persistence and dissipation in dry soil using bioindicator. Five experiments were carried out, divided into two phases. In the first phase, three dose-response curves were adjusted to select the best bioindicator to be adopted in the second phase. Niger was adopted due to its lower sensibility to sulfentrazone. In the second phase, a new dose-response curve was carried out, with six doses of sulfentrazone, in order to standardize the bioindicator sensibility to sulfentrazone. At the end, another experiment with six periods of sulfentrazone persistence in dry clay soil was developed. Persistence periods were: 182, 154, 125, 98 and 30 days. The bioindicator was seeded at the application day in treated plots and control. In this experiment, the sulfentrazone dose applied was 800 g ha-1. Niger was considered a good species to estimate the sulfentrazone persistence in dry soil. The sulfentrazone phytotoxic activity was identified up to 182 days after application, and its average dissipation rate was 2.15 g ha-1 day-1, with half-life higher than 182 days.

The Effect of MA Transmutation in the PWR on Fuel Cycle

2017 ◽  
Author(s):  
Haoyang Yu ◽  
Bin Liu ◽  
Wenxin Zhang ◽  
Jin Cai
Keyword(s):  
Fuel Cycle ◽  
Minor Actinide ◽  
Minor Actinides ◽  
Pressurized Water Reactor ◽  
Spent Fuel ◽  
Pressurized Water ◽  
Mcnp Program ◽  
And Control ◽  
Control Rods ◽  
Effective Multiplication

The minor actinides (MA) is important nuclides in the spent fuel which is bad for human ecological environment. Pressurized water reactor (PWR) is the main reactor type at commercial operation around world. It is important to find the appropriate loading patterns when introducing minor actinides to the PWR core. In this paper, we study the effect of MA transmutation in the PWR on fuel cycle. First, we use the MCNP program to simulate the model of PWR and the effective multiplication factor.Then,the MA is introduced into core in different ways and mass to simulate the effective multiplication factor. In conclusion,without considering chemical skim control and control rods, we change the thickness of the MA, until the keff closes to 1, We find that loading minor actinides to burnable poison rods for transmutation is an optimal minor actinide loading pattern.

A study of burnup credit in criticality safety analysis for PBR spent fuel pebbles

2019 ◽  
Vol 132 ◽  
pp. 347-356 ◽  
Author(s):  
Shang-Chien Wu ◽  
Der-Sheng Chao ◽  
Jenq-Horng Liang
Keyword(s):  
Safety Analysis ◽  
Spent Fuel ◽  
Criticality Safety

scholarly journals SAFETY ANALYSIS OF NEUTRON INTERACTION WITH MATERIAL PRACTICUM MODULE FOR THE KARTINI INTERNET REACTOR LABORATORY

2020 ◽  
Vol 22 (3) ◽  
pp. 104
Author(s):  
Prasetyo Haryo Sadewo ◽  
Puradwi Ismu Wahyono
Keyword(s):  
Radiation Protection ◽  
Nuclear Reactor ◽  
Power Level ◽  
Safety Analysis ◽  
Reactor Physics ◽  
Control Rod ◽  
Reactor Kinetics ◽  
Additional Equipment ◽  
Activation Products ◽  
And Control

Kartini Research Reactor, which is situated in Yogyakarta, is a 100 kW TRIGA (Training, Research, and Isotope Production by General Atomic)-type reactor mainly used for educational and training purposes. A system for remote learning on nuclear reactor physics named the Internet Rector Laboratory has been developed and is fully operational since 2019. To enrich its curriculum, a new practicum module has been developed, that can be immediately implemented and does not require any additional equipment or materials. To ensure safety in reactor kinetics and radiation protection, a safety analysis on the implementation of the practicum module has been conducted using MCNP and ORIGEN utilizing the current conditions of the reactor regarding its fuel burnup and control rod positions at a certain power level. Based on the results of the analysis, the practicum is safe to perform from a neutronic and radiation protection perspective. Given the long half-life and the large amount of radiation exposure that comes from activation products of iron, it is recommended that only cadmium, boron, graphite, and aluminum are allowed to be irradiated during the practicum.Keywords: Internet Reactor Laboratory, Activation Product, Radiation Protection, Reactor Safety

scholarly journals Mathematical model of transmission dynamics with mitigation and health measures for SARS-CoV-2 infection in European countries

2020 ◽  
Author(s):  
Shweta Sankhwar ◽  
Narender Kumar ◽  
Ravins Dohare
Keyword(s):  
Mathematical Model ◽  
Basic Reproduction Number ◽  
Reproduction Number ◽  
European Countries ◽  
Transmission Dynamics ◽  
Second Phase ◽  
Geographical Regions ◽  
Two Phases ◽  
Spread Of Infection ◽  
And Control

Abstract The pandemic of Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) continue to pose a serious threat to global health resulting in disease COVID-19. No specific drug or vaccine is available against this infection. Therefore, the prevention is only way to reduce the spread of infection. The pandemic needs an enhanced mathematical model, therefore, we propose a SEIAJR compartmental mathematical model to estimate the basic reproduction number (R0 ) and the transmission dynamics of four European countries (Germany, United Kingdom, Switzerland and Spain). The proposed mathematical model incorporates mitigation and healthcare measures as recommended by ECDC (European Centre for Disease Prevention and Control). The simulation of proposed model is done in two phases. First-phase simulation estimates basic reproduction number and mitigation rate according to active infected cases in all four European countries. R0 estimate 2.82 - 3.3 for considered European countries. Second-phase simulation predicts the dynamics of infection on the estimated R0 with varying mitigation rate and constant healthcare rate. This study predicts that no more mitigation is required to invade the infection. The current mitigation and healthcare measures are enough to stop the propogation of infection, however, infection would last by end of July 2020. The developed mathematical model would also be applicable to portray the infection trasmission dynamics for other geographical regions with varying parameters.

Release of 108Ag from Irradiated PWR Control Rod Absorbers under Deep Repository Conditions

2015 ◽  
Vol 1744 ◽  
pp. 217-222
Author(s):  
O. Roth ◽  
M. Granfors ◽  
A. Puranen ◽  
K. Spahiu
Keyword(s):  
Nuclear Fuel ◽  
Source Term ◽  
Spent Nuclear Fuel ◽  
Nuclear Reactors ◽  
Reactor Irradiation ◽  
Spent Fuel ◽  
Control Rod ◽  
Potential Source ◽  
Absorber Material ◽  
Control Rods

ABSTRACTIn a future Swedish deep repository for spent nuclear fuel, irradiated control rods from PWR nuclear reactors are planned to be stored together with the spent fuel. The control rod absorber consists of an 80% Ag, 5% Cd, 15% In alloy with a steel cladding. Upon in-reactor irradiation 108Ag is produced by neutron capture. Release of 108Ag has been identified as a potential source term for release of radioactive substances from the deep repository.Under reducing deep repository conditions, the Ag corrosion rate is however expected to be low which would imply that the release rate of 108Ag should be low under these conditions. The aim of this study is to investigate the dissolution of PWR control rod absorber material under conditions relevant to a future deep repository for spent nuclear fuel. The experiments include tests using irradiated control rod absorber material from Ringhals 2, Sweden. Furthermore, un-irradiated control rod absorber alloy has been tested for comparison. The experiments indicate that the release of Ag from the alloy when exposed to water is strongly dependent on the redox conditions. Under aerated conditions Ag is released at a significant rate whereas no release could be measured after 133 days during leaching under H2.

scholarly journals Methods and Models for the Coupled Neutronics and Thermal-Hydraulics Analysis of the CROCUS Reactor at EFPL

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
A. Rais ◽  
D. Siefman ◽  
G. Girardin ◽  
M. Hursin ◽  
A. Pautz
Keyword(s):  
Power Distribution ◽  
Reactor Core ◽  
Transient Behavior ◽  
Nuclear Data ◽  
Safety Analysis ◽  
Monte Carlo Code ◽  
Thermal Hydraulics ◽  
Control Rod ◽  
Nuclear Data Library ◽  
And Control

In order to analyze the steady state and transient behavior of the CROCUS reactor, several methods and models need to be developed in the areas of reactor physics, thermal-hydraulics, and multiphysics coupling. The long-term objectives of this project are to work towards the development of a modern method for the safety analysis of research reactors and to update the Final Safety Analysis Report of the CROCUS reactor. A first part of the paper deals with generation of a core simulator nuclear data library for the CROCUS reactor using the Serpent 2 Monte Carlo code and also with reactor core modeling using the PARCS code. PARCS eigenvalue, radial power distribution, and control rod reactivity worth results were benchmarked against Serpent 2 full-core model results. Using the Serpent 2 model as reference, PARCS eigenvalue predictions were within 240 pcm, radial power was within 3% in the central region of the core, and control rod reactivity worth was within 2%. A second part reviews the current methodology used for the safety analysis of the CROCUS reactor and presents the envisioned approach for the multiphysics modeling of the reactor.

scholarly journals The effects of early zinc deficiency on DNA and protein synthesis in the rat

1970 ◽  
Vol 24 (4) ◽  
pp. 1053-1059 ◽  
Author(s):  
R. B. Williams ◽  
J. K. Chesters
Keyword(s):  
Food Consumption ◽  
Zinc Deficiency ◽  
Protein Metabolism ◽  
Initial Period ◽  
Zn Deficiency ◽  
Second Phase ◽  
Control Groups ◽  
Dna And Protein Synthesis ◽  
Two Phases ◽  
And Control

1. The effects of early zinc deficiency on DNA and protein metabolism of the liver, kidneys, testes and spleen of the young rat were studied. The investigations were carried out in two phases: before food consumption and growth were affected, and afterwards.2. The incorporation of [3H]thymidine into DNA was markedly affected by differences of less than a week in the age of the rats.3. Zn deficiency significantly reduced the incorporation of [3H]thymidine into DNA of liver, kidneys and spleen before growth and food consumption were affected. The degree of inhibition was of the order of 50% in the first 5 d. A similar but non-significant trend was observed for the testes.4. The incorporation of [3C]lysine into protein was not significantly affected in liver and testes during the initial period of Zn deficiency; the incorporation into kidneys and spleen was significantly inhibited but the magnitude of the effect was only of the order of 20% in 5d.5. One week after the start of the second phase, the concentration of DNA in liver, testes, and spleen of Zn-deficient animals was not significantly different from that in pair-fed controls. The DNA content of the kidneys was significantly reduced by the deficiency hut only to 97% of that in pair-fed animalsgiven the Zn-supplcmenteddiet. The incorporation of [3H]thymidine into DNA was not significantly different between deficient and control groups in any of the four organs investigated.

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