Hot Laboratory Research Articles

Massive Protostellar Disks as a Hot Laboratory of Silicate Grain Evolution

Typical accretion disks around massive protostars are hot enough for water ice to sublimate. We here propose to utilize the massive protostellar disks for investigating the collisional evolution of silicate grains with no ice mantle, which is an essential process for the formation of rocky planetesimals in protoplanetary disks around lower-mass stars. We, for the first time, develop a model of massive protostellar disks that includes the coagulation, fragmentation, and radial drift of dust. We show that the maximum grain size in the disks is limited by collisional fragmentation rather than by radial drift. We derive analytic formulae that produce the radial distribution of the maximum grain size and dust surface density in the steady state. Applying the analytic formulae to the massive protostellar disk of GGD27-MM1, where the grain size is constrained from a millimeter polarimetric observation, we infer that the silicate grains in this disk fragment at collision velocities above ≈10 m s−1. The inferred fragmentation threshold velocity is lower than the maximum grain collision velocity in typical protoplanetary disks around low-mass stars, implying that coagulation alone may not lead to the formation of rocky planetesimals in those disks. With future measurements of grain sizes in massive protostellar disks, our model will provide more robust constraints on the sticking property of silicate grains.

Electron inelastic mean free path in UO2 and (U, Pu)O2 fuels

Inelastic mean free path (IMFP) of UO2 and (U, Pu)O2 fuels at 0, 20, 50 and 95 at.% of Pu were determined for the first time using a combination of convergent beam electron diffraction (CBED) and electron energy loss spectroscopy (EELS) on TEM FIB lamellae. Non-linear least squares fit was performed on the CBED intensity profiles to only obtain the crystalline thickness of the sample with a precision of up to 0.2% [1] while EELS spectra were used to calculate the relative thickness of the sample: crystalline and amorphous contribution. The IMFP were determined to be 119 – 129 nm for UO2, 107 – 117 nm for (U, Pu)O2 at 20 at.% of Pu, 116 – 125 nm for (U, Pu)O2 at 50 at.% of Pu and 123 – 137 nm for (U, Pu)O2 at 95 at.% of Pu using collection semi-angles β = 23.4 – 11.6 mrad, convergence semi-angle α = 8 mrad and accelerated voltage of 200 keV on a Thermofischer TALOS F200X TEM in the LECA STAR hot laboratory (CEA Cadarache). A comparison with the most relevant models in the literature shows that for compounds with a comparable quantity of light and heavy elements it is better to use a mean atomic number instead of an effective one as proposed by different authors. The importance of accurate density determination is also emphasized if the IMFP values are to be predicted by the existed models. As a second part, a strategy is developed to calculate the effective refractive index at the nanometer scale for the fuels allowing to easily find the IMFP under different measurement parameters such as those in energy filtered transmission electron microscopy (EFTEM) maps.

Evolution of phenotypic variance in response to a novel hot environment.

Shifts in trait means are widely considered as evidence for adaptive responses, but the impact on phenotypic variance remains largely unexplored. Classic quantitative genetics provides a theoretical framework to predict how selection on phenotypic mean affects the variance. In addition to this indirect effect, it is also possible that the variance of the trait is the direct target of selection, but experimentally characterized cases are rare. Here, we studied gene expression variance of Drosophila simulans males before and after 100generations of adaptation to a novel hot laboratory environment. In each of the two independently evolved populations, the variance of 125 and 97genes was significantly reduced. We propose that the drastic loss in environmental complexity from nature to the laboratory may have triggered selection for reduced variance. Our observation that selection could drive changes in the variance of gene expression could have important implications for studies of adaptation processes in natural and experimental populations.

Specific of the Recrystallization Driving Force Calculation on the early Stages of Thermomechanical Treatment of Aluminum Alloys

The article investigates the effect of the strain rate on the driving force of recrystallization during hot working of the as-cast structure. For the study, we applied previously obtained experimental data of recrystallization kinetics during this stage of thermomechanical treatment. In addition, hot laboratory rolling, followed by saltpeter bath soaking, were performed in order to obtain supplemental data on grain structure size and orientations. Grain structure size was examined by optical microscopy, and its orientation was examined by X-ray texture analysis. The studies demonstrated, that overestimated recrystallization driving force not only results in erroneous kinetics estimation, but also gives excessive number of recrystallization centers and undersized grain structure. Besides, unaccounted effect of recrystallization driving force on grain size leads to distorted predictions of texture composition. In order to avoid this, it was recommended to apply an special exponential accumulated strain dependent coefficient.

Characterisation and Modelling of Drying Kinetics of Thin Ash and Oak Wood Lamellas Dried with Infrared Radiation and Hot Air

Infrared and hot air drying characteristics of thin ash (Fraxinus excelsior L.) and oak (Quercus robur L.) wood lamellas were experimentally determined using an infrared and hot air laboratory device. Drying curves of 2 mm thick lamellas were established in the temperature range between 60 °C and 90 °C, and fitted by Fick’s diffusion model. Drying efficiency, drying rate and effective diffusivity have been estimated and compared between the used drying techniques. Moisture ratio exponentially decayed with duration of the process at all used temperatures. Effective diffusivity was greater in ash than oak wood, and it was not significantly influenced by the drying technique. The increased bound water diffusivity with increased drying temperature that caused shortening of the drying process was confirmed in both wood species. Similar activation energy was determined with both wood species, lower when the IR drying technique was used.

The Effect of an Optimized Cooling Vest for Controlling the Women’s Thermal Strain in the Hot Laboratory Conditions

Background: Continuous activities in hot environments are a serious threat to people’s health in society, especially in women. Objectives: Therefore, the purpose of this study was to evaluate the effect of an optimized cooling vest to control the women's thermal strain in the hot laboratory conditions. Methods: The cooling vest (1500 g) was designed for women. This study carried out on 20 female students in a climatic chamber (37°C, humidity, 39%) on a treadmill (2 km/h and zero-degree gradient) in two modes, with the cooling vest (6 steps in 10 min) and without the cooling vest (4 stages in 10 min). The measured parameters at certain time points included heart rate, oral temperature, thermal sensation (TS), perceived exertion (PE), as well as physiological and perceptual strain indices (PSI and PeSI). Ultimately, the data were analyzed by SPSS software (Ver. 22), and the paired t-test was used to compare the data at different time points. Results: The statistical analysis showed a significant difference between the mean TS, PE, PeSI, and PSI in the two test modes (P 0.05). Conclusions: Considering the positive effects of the designed cooling vest for perceptual and physiological heat strain for women, it can be used as a useful and cost-effective solution in the warm environment to reduce the effects of exposure to heat.

Selective Cs-removal from highly acidic spent nuclear fuel solutions

Abstract Thirty liters of highly acidic spent nuclear fuel solutions need to be disposed at the “Hot Laboratory (hotlab)” facility in Paul Scherrer Institut (PSI), Switzerland. In order to significantly reduce the γ dose rate before proper disposal treatment, 137Cs must be removed. In the here presented sub-project, the ion-exchange method was evaluated. Two promising sorbents, CLEVASOL® and AMP (ammonium molybdophosphate), and two derived products AMP_PAN (AMP immobilized in polyacrylonitrile) and AMP/SiO2 (AMP immobilized on silica gel) were tested by the batch method using model solutions of important high-yield fission products (Cs, Eu, Zr, Ru, Pd and Ag), as well as U and Pu. The results showed that AMP, AMP/SiO2 and AMP_PAN have higher selectivity for Cs than CLEVASOL® in 0.1–8 M (mol/L) HNO3 solutions. 4 M HNO3 solution was identified as the most suitable condition for Cs-removal with AMP, AMP_PAN and AMP/SiO2 due to the still sufficiently high separation factor of Cs from other metal ions and an acceptable volume increase factor after dilution. The follow-up kinetic studies on AMP, AMP_PAN and AMP/SiO2 indicated that although Cs exchange on AMP and AMP/SiO2 is faster than on AMP_PAN in the first 5 min, they all nearly reach equilibrium after 30 min of contacting time. The isotherm curves of Cs adsorption on AMP, AMP_PAN and AMP/SiO2 in 4 M HNO3 showed that the maximum sorption capacity of Cs is reached asymptotically. The results from Langmuir isotherm modeling agree with results from other publications.

The unified model for irradiation embrittlement prediction of reactor pressure vessel

The irradiation embrittlement of reactor pressure vessel (RPV) steel is the top priority for nuclear power operation safety. In this work, neutron irradiation experiments were performed on a commercial RPV steel at a high temperature using a neutron irradiation experimental reactor, then the mechanical and electromagnetic properties measurements were performed in a hot laboratory. The results show that there is a unified exponential function relationship between the variability of mechanical and electro-magnetic properties for RPV steels during neutron irradiation embrittlement, and the fitting accuracy results show that the prediction unified model is scientific, practical and effective. The theoretical basis of prediction unified model is that both mechanical and electromagnetic properties are external manifestations of the microstructure evolution for RPV under neutron irradiation. Finally, this paper points out that based on the prediction unified model, it can be developed into a non-destructive evaluation technique for RPV irradiation embrittlement with many advantages.

Superficial skin cancer therapy with Y-90 microspheres: A feasibility study on patch preparation.

Radiation therapy using beta particles is an interesting treatment for very superficial skin lesions. Due to their low penetration in tissue and rapid dose fall-off, beta particles can protect underlying bony structures and surrounding healthy tissue while irradiating the skin tumor. In the current work, a simple method for the fabrication of a radioactive patch for use in skin cancer therapy based on a beta-emitting isotope is presented. The beta radiation sources were Y-90 microspheres currently used for catheter-based radioembolization of unresectable liver tumors. The microspheres were filtered through a syringe filter to trap them on the cellulose nitrate paper of the filter and create a radioactive patch. In the current study, to avoid the need for a hot laboratory, the experiment was done using nonradioactive microspheres. An optical microscope was used to verify the distribution of the particles on the filter paper. Visual evaluation of the patches showed that using the proposed method, therapeutic skin patches with a fairly uniform distribution of microspheres can be created. The proposed simple method may be used in creating radiotherapeutic patches using Y-90 microspheres for radiation therapy of thinskin lesions located close to sensitive structures.

Effects of neutron irradiation on elastic modulus of RPV steel

The embrittlement of reactor pressure vessel (RPV) steel owing to fast- neutron irradiation damage is one of its primary failure mechanisms. In this work, neutron irradiation experiments were performed on a commercial RPV steel at a high temperature (292 °C) using a neutron irradiation experimental reactor. Then the elastic modulus measurements and XRD analysis were performed on the RPV steel before and after irradiation in a hot laboratory. The results shows that the Young modulus and shear modulus of RPV steel do not change during neutron irradiation, the half-width of peak shape parameters and lattice constant of XRD diffraction peak remain unchanged, and no new phase is formed in RPV steel during irradiation embrittlement, the crystal structure of RPV steel does not change after neutron irradiation damage. It is found that the elastic modulus of the macro-mechanical properties and the micro-structure characterized by XRD analysis are consistent with each other during the neutron irradiation embrittlement process of RPV steel. Finally, this paper points out that the conclusion of neutron irradiation damage has no effect on the elastic modulus of RPV steel is of great significance to the structural integrity analysis and safety evaluation of RPV in the whole life of nuclear power plant.

Waste Management in a Hot Laboratory of Japan Atomic Energy Agency – 3: Volume Reduction and Stabilization of Solid Waste

Waste Management in a Hot Laboratory of Japan Atomic Energy Agency – 3: Volume Reduction and Stabilization of Solid Waste

A 24 h Age Difference Causes Twice as Much Gene Expression Divergence as 100 Generations of Adaptation to a Novel Environment.

Gene expression profiling is one of the most reliable high-throughput phenotyping methods, allowing researchers to quantify the transcript abundance of expressed genes. Because many biotic and abiotic factors influence gene expression, it is recommended to control them as tightly as possible. Here, we show that a 24 h age difference of Drosophila simulans females that were subjected to RNA sequencing (RNA-Seq) five and six days after eclosure resulted in more than 2000 differentially expressed genes. This is twice the number of genes that changed expression during 100 generations of evolution in a novel hot laboratory environment. Importantly, most of the genes differing in expression due to age introduce false positives or negatives if an adaptive gene expression analysis is not controlled for age. Our results indicate that tightly controlled experimental conditions, including precise developmental staging, are needed for reliable gene expression analyses, in particular in an evolutionary framework.

Effects of neutron irradiation on magnetic properties of reactor pressure vessel steel

Abstract A primary failure mechanism of reactor pressure vessel (RPV) steel is the embrittlement caused by fast-neutron irradiation. In this work, neutron irradiation tests were performed on an RPV steel at a high temperature (292 °C) using a neutron irradiation test reactor. In addition, its magnetic properties were measured before and after irradiation in a hot laboratory. These measurements show that (i) the clockwise variation of the magnetisation for the hysteresis loops of RPV steel before irradiation was lower than that after it; (ii) sample magnetisation before and after irradiation was not sensitive to changes in temperature, with only a very small hysteresis effect; and (iii) when irradiation damage did not exceed 0.154 dpa, the residual magnetisation intensity of the RPV steel was linear to the radiation fluence, and the initial magnetic susceptibility exhibited an exponential relationship with the radiation fluence. Finally, the magnetic properties of the RPV steel can be used to characterise the degree of its irradiation-induced embrittlement, and measurements of magnetic properties can be used for non-destructive evaluation in monitoring the degree of irradiation damage experienced by in-service RPV steel.

P111] Eye lens exposure to ionising radiation in personnel of a nuclear medicine department.

Purpose The aim of the study was to estimate equivalent doses in the eye lens in employees of the Nuclear Medicine Department of the Pomeranian Medical University (PMU) in Szczecin. The European Directive 2013/59 limited the annual eye lens dose to 20 mSv, which stimulated the need to estimate equivalent doses in clinical laboratories using ionising radiation in diagnostic and therapeutic procedures. Methods 10 employees (2 doctors, 5 technicians and 3 nurses) used personal eye dosimeters for a total time of 3 months. Dosimeters were supplied by and analysed for their indications by the Institute of Nuclear Physics, Polish Academy of Sciences (IFJ PAN) in Krakow. Technicians and nurses in the Nuclear Medicine Department PMU prepared radioisotopes for patients in a hot laboratory in a rotation system. Results Personnel preparing and administering radiopharmaceuticals with iodine I-131 to patients (2 doctors and 1 technician) received an average equivalent dose of 11.63 μ Sv per GBq of activity. Technicians preparing radiopharmaceuticals labelled with technetium Tc99m were exposed to an equivalent dose of 0.002 μ Sv/GBq. Nurses preparing and administering radiopharmaceuticals labelled with technetium Tc99m were exposed on average to an equivalent dose of 0.006 μ Sv/GBq. Doses registered during 3-month personal eye dosimetry ranged from max. 0.42 mSv to min. 0.20 mSv. The estimated maximum annual eye lens dose per employee in the NMD department was not higher than 2.5 mSv. Conclusions Personnel of the Nuclear Medicine Department PMU do not require personal eye dose monitoring while performing their routine duties. Personnel preparing and administering radiopharmaceuticals to patients may use leaded eyewear for protection.

Development of a new bench for puncturing of irradiated fuel rods in STAR hot laboratory

A new device for puncturing of irradiated fuel rods in commercial power plants has been designed by Fuel Research Department of CEA Cadarache in order to provide experimental data of high precision on fuel pins with various designs. It will replace the current set-up that has been used since 1998 in hot cell 2 of STAR facility with more than 200 rod puncturing experiments. Based on this consistent experimental feedback, the heavy-duty technique of rod perforation by clad punching has been preserved for the new bench. The method of double expansion of rod gases is also retained since it allows upgrading the confidence interval of volumetric results obtained from rod puncturing. Furthermore, many evolutions have been introduced in the new design in order to improve its reliability, to make the maintenance easier by remote handling and to reduce experimental uncertainties. Tightness components have been studied with Sealing Laboratory Maestral at Pierrelatte so as to make them able to work under mixed pressure conditions (from vacuum at 10-5 mbar up to pressure at 50 bars) and to lengthen their lifetime under permanent gamma irradiation in hot cell. Bench ergonomics has been optimized to make its operating by remote handling easier and to secure the critical phases of a puncturing experiment. A high pressure gas line equipped with high precision pressure sensors out of cell can be connected to the bench in cell for calibration purposes. Uncertainty analyses using Monte Carlo calculations have been performed in order to optimize capacity of the different volumes of the apparatus according to volumetric characteristics of the rod to be punctured. At last this device is composed of independent modules which allow puncturing fuel pins out of different geometries (PWR, BWR, VVER). After leak tests of the device and remote handling simulation in a mock-up cell, several punctures of calibrated specimens have been performed in 2016. The bench will be implemented soon in hot cell 2 of STAR facility for final qualification tests. PWR rod punctures are already planned for 2018.

Effects of neutron irradiation on resistivity of reactor pressure vessel steel

The embrittlement of reactor pressure vessel (RPV) steel owing to fast-neutron irradiation is one of its primary failure mechanisms. In this work, neutron irradiation tests were performed on an RPV steel at a high temperature (565 K) using a neutron irradiation test reactor. In addition, resistivity measurements were performed on the RPV steel both before and after irradiation in a hot laboratory using the four-probe method. The results showed that the resistivity of the RPV steel exhibits nonlinear behaviour with respect to the radiation fluence and that the nonlinearity becomes more pronounced with an increase in the radiation fluence. For instance, when the radiation fluence is 0.1540 dpa and the excitation current is increased from 0.2 mA to 200 mA, the resistivity of the RPV steel decreases by as much as 67.12%. During irradiation embrittlement, the resistivity increases with the fluence. When the radiation fluence is greater than 0.116 dpa, the increase in the resistivity accelerates. When the radiation fluence is less than 0.116 dpa and when an excitation current of 2 mA or 20 mA is used, the relationship between the resistivity and the radiation fluence for the RPV steel is a quadratic one, whereas that between the rate of change in the resistivity and the radiation fluence is a linear one. Thus, the resistivity of RPV steel can be used to characterise its degree of irradiation embrittlement, and resistivity measurements can be employed as a nondestructive evaluation technique for monitoring the degree of irradiation damage experienced by in-service RPV steel.

Effect of Re-Oxidation Rate of Additive Cation on Corrosion Rate of Stainless Steel in Boiling Nitric Acid Solution.

Fuel reprocessing plant is important for atomic energy cycle which is aimed to re-use uranium (U) and plutonium (Pu) from the spent nuclear fuels after barning-out in light water reactor. PUREX process, in which boiling nitric acid is used for dissolving fuel elements, is adopted in Japan. Many structural materials are used stainless steels protected by passive layers of the surface. At the beginning of developing the plant, many troubles of intergranular corrosion of stainless steels were experienced. According to the investigations of these problems, very low carbon type austenitic stainless steels were utilized for the materials.However, these stainless steels were corroded in some cases. For example, addition of hexavalent chromium (Cr (VI)) is heavily accelerated corrosion rate of these stainless steels in boiling nitric acid solutions. The corrosion potential of stainless steel in Cr (VI) added solution is much higher than that in pure nitric acid solution.The authors introduced that heptavalent vanadium (V (V)) was also accelerated corrosion rate of these stainless steels but the tendency of acceleration process was different from the case of containing Cr (VI). We analyzed the valence stats of Cr and V during corrosion test and showed that Cr (VI) reduced to Cr (III) with corrosion of stainless steel propagating. On the other hand, amount of V (V) was not changed during the corrosion test. It was concluded that V (IV) was easily re-oxidized in boiling nitric acid solution. Namely, V (V) is reduced to V (IV) on stainless steel surface by cathodic reaction of corrosion and then V (IV) is re-oxidized immediately to V (V) in the balk nitric acid solution.These data were obtained using non-radioactive solutions in the ordinary laboratory. The present work is aimed to compare the data of re-oxidation rate of actinides which are included in the actual solutions used in a reprocessing plant. We implemented a specially designed electrochemical test cell used for analyzing the valence states of actinide cations, i.e. neptunium (Np) and Pu, in a boiling nitric acid solution. The cell was set into glovebox in a hot laboratory which could be handled nuclear fuel materials. The cell was designed for minimizing the solution. The amounts of solution used are about 15 cm3 and sample size of working electrode is about 4 mm2. Electrochemical measurements and spectrum analyses were conducted with this apparatus. Analyzed cations were Cr (VI), V (V), Pu (VI) and Np (VI). Polarization curves showed that corrosion potentials of stainless steels changed to higher direction by addition of these cations and also corrosion current densities increased. The higher order of those is Cr (VI), Np (VI), V (V) and Pu (VI). Re-oxidation rates were obtained by the changes of absorption spectra with time using lower valence state ions added solutions, i.e. Cr (III), V (IV), Pu (IV) and Np (V). These species are re-oxidized to Cr (VI), V (V), Pu (VI) and Np (VI), respectively. Re-oxidation rates of them were very much different among them. Very fast re-oxidation rates were obtained by the V (IV) and Np (V) added solutions. A very low re-oxidation rate was obtained by the Cr (III) added solution. The Pu (IV) added solution was in the middle of them. The corrosion of stainless steel is controlled by corrosion potential of cation added solution at the initial stage and controlled by re-oxidation rate of cation as time passed. The element Np which indicates high corrosion potential and has fast re-oxidation rate influences too much the corrosion of stainless steel in boiling nitic acid solution among these elements in consideration.

Analysis of effects of pellet-cladding bonding on trapping of the released fission gases in high burnup KKL BWR fuels

The first part of the paper presents results of a numerical analysis of the fuel behavior during base irradiation in the Kernkraftwerk Leibstadt Boiling Water Reactor (KKL BWR) using EPRI’s FALCON code coupled to GRSW-A – an advanced model for fuel swelling and fission gas release. Post-irradiation examinations conducted at the Paul Scherrer Institute’s (PSI) hot laboratory gave evidence of a distinct circumferential non-uniformity of local burnup at pellet surfaces. For several fuel samples, intact pellet-cladding bonding areas on the high burnup sides of the pellets at high burnup above ∼70MWd/kgU were observed. It is hypothesized that a part of the fission gases, which are expected to be released by those areas, can be trapped and do not reach the rod plenum. In this paper, a simple approach to modeling of fission gas trapping is employed which reveals a potential correlation between the position of the rod within the fuel assembly (and therefore the degree of circumferential burnup non-uniformity) and the degree of fission gas trapping. A model is suggested to correlate the amount of locally trapped gas with the integral of the local contact pressure and the degree of circumferential burnup non-uniformity. The model is calibrated with available measurements of FGR from rod puncturing at the level of the plenums. In future work, the hypothesis about the axial distribution of trapped fission gas will be extrapolated to the Loss-Of-Coolant Accident (LOCA) analysis as an attempt to explain the fission gas release observed in some samples fabricated from irradiated KKL fuel rods and tested in the OECD Halden Reactor Project’s LOCA test program.

The characterization of near‐surface defects evolved on aluminum–manganese alloys during hot rolling

Hot rolling laboratory experiments were performed on an Al–Mn alloy, utilizing a rolling tribo‐simulator to characterize the evolution of near‐surface defects induced by tribological interactions between the work roll and alloy surfaces. A ten pass hot rolling schedule was conducted on Al–Mn samples using an AISI 52100 work roll polished to a surface roughness (Ra) of 0.01 μm. Micro‐cracks formed on the alloy surfaces at the first pass were observed to initiate at grain boundaries and propagate less than 1.5 μm deep into the subsurface region. The faces of the micro‐cracks in the subsurface region were observed to be covered with MgO. The surface of the samples were observed to possess a top 90‐nm‐thick oxide‐rich layer, which was mostly composed of MgO. MgAl2O4 and Al2O3 were also observed on the alloy surface at this stage of rolling. After ten passes, near‐surface features on the Al–Mn alloy samples included MgO‐rich islands and transverse cracks. Cracks extended more than 2 μm deep into the subsurface. Crack faces were covered with surface deformation induced crevices as well as MgO. The near‐surface was also composed of nano‐crack induced damaged areas, filled with porous nanocrystalline oxides. These damaged areas extended 0.5 μm into the subsurface region beneath a 60‐nm‐thick MgO film. The nanocrystalline oxide layers possessed embedded aluminum nano‐particles. The microstructure of the near‐surface layer suggests that magnesium diffusion to the free surfaces and crack formation play an important role in its evolution. Copyright © 2015 John Wiley & Sons, Ltd.

Effects of a moderate intake of beer on markers of hydration after exercise in the heat: a crossover study

BackgroundExercise in the heat causes important water and electrolytes losses through perspiration. Optimal rehydration is crucial to facilitate the recuperation process after exercise. The aim of our study was to examine whether a moderate beer intake as part of the rehydration has any negative effect protocol after a short but dehydrating bout of exercise in the heat.MethodsSixteen active male (VO2max, 56 ± 4 mL/kg/min), were included in a crossover study and performed a dehydrating exercise (≤1 h running, 60 %VO2max) twice and 3 weeks apart, in a hot laboratory setting (35 ± 1 °C, humidity 60 ± 2 %). During the two hours following the exercise bouts participants consumed either mineral water ad-libitum (W) or up to 660 ml regular beer followed by water ad-libitum (BW). Body composition, hematological and serum parameters, fluid balance and urine excretion were assessed before, after exercise and after rehydration.ResultsBody mass (BM) decreased (both ~ 2.4 %) after exercise in both trials. After rehydration, BM and fat free mass significantly increased although BM did not return to baseline levels (BM, 72.6 ± 6.7 to 73.6 ± 6.9; fat free mass, 56.9 ± 4.7 to 57.5 ± 4.5, no differences BW vs W). Beer intake did not adversely affect any measured parameter. Fluid balance and urine excretion values did not differ between the rehydration strategies.ConclusionsAfter exercise and subsequent water losses, a moderate beer (regular) intake has no deleterious effects on markers of hydration in active individuals.Electronic supplementary materialThe online version of this article (doi:10.1186/s12970-015-0088-5) contains supplementary material, which is available to authorized users.