scholarly journals CALCULATION OF CONTROL AND ACCEPTABLE LEVELS OF RADIATION FACTORS FOR NUCLEAR PROPULSIONS

2019 ◽  
Vol 5 (2) ◽  
pp. 76-82
Author(s):  
B. I. Zhabrunov ◽  
A. A. Kern ◽  
A. S. Tazov ◽  
B. V. Kutashov
Keyword(s):  
Lower Limit ◽  
Radiation Safety ◽  
Power Level ◽  
Test Procedure ◽  
Mean Value ◽  
Measured Data ◽  
Reactor Power ◽  
Radiation Factor ◽  
Measuring Range ◽  
Acceptable Error

In accordance with requirements of regulatory and guideline documents on radiation safety for controlled radiation factors for the purposes of operating control, controlled and acceptable levels are established. Any excess of these levels requires the determination of the causes and implementation of actions designed to eliminate the excess. The paper presents the method of calculation of these levels and establishing the levels in practice at the present time, disadvantages of accepted regulations are analyzed. It was shown that existing documents do not take into account some circumstances that define the radiation safety test procedure. In a number of measured control points of the radiological situation and staff radiation exposure, the values of controlled parameters are independent of reactor system mode. In the same points that show the dependence of measured data on a reactor power level, values of controlled parameters may also depend on a mode of pumps and purification system. Furthermore, real-time measurements review has showed that beyond the range of lower limit of measuring range of verification means in the range with nonspecified error, the measured data variance is described by mean value and acceptable error. At the same time, a mean value may be a lower order to lower limit of measuring range. Setting a value of controlled level equal to a sum of a mean of double or tripled root-mean-square deviation depending on the accepted confidence level, a possibility of earlier detection of controlled level excess emerges. In this situation, an exact absolute value of a controlling parameter is not essential as that radiation factor level poses no hazard to life. It is important to capture the onset of significant increase of radiation factor i.e. change of radiological situation.

scholarly journals The Local Seismoacoustic Wavefield of a Research Nuclear Reactor and Its Response to Reactor Power Level

2020 ◽  
Vol 92 (1) ◽  
pp. 378-387
Author(s):  
Omar E. Marcillo ◽  
Monica Maceira ◽  
Chengping Chai ◽  
Christine Gammans ◽  
Riley Hunley ◽  
...  
Keyword(s):  
Energy Transport ◽  
Nuclear Reactor ◽  
Power Level ◽  
National Laboratory ◽  
Reactor Power ◽  
Operational Conditions ◽  
Oak Ridge ◽  
Research Nuclear Reactor ◽  
Full Power ◽  
Power Operation

Abstract We describe the seismoacoustic wavefield recorded outdoors but inside the facility fence of the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (Tennessee). HFIR is a research nuclear reactor that generates neutrons for scattering, irradiation research, and isotope production. This reactor operates at a nominal power of 85 MW, with a full-power period between 24 and 26 days. This study uses data from a single seismoacoustic station that operated for 60 days and sampled a full operating reactor cycle, that is, full-power operation and end-of-cycle outage. The analysis presented here is based on identifying signals that characterize the steady, that is, full-power operation and end-of-cycle outage, and transitional, that is, start-up and shutdown, states of the reactor. We found that the overall seismoacoustic energy closely follows the main power cycle of the reactor and identified spectral regions excited by specific reactor operational conditions. In particular, we identified a tonal noise sequence with a fundamental frequency around 21.4 Hz and multiple harmonics that emerge as the reactor reaches 90% of nominal power in both seismic and acoustic channels. We also utilized temperature measurements from the monitoring system of the reactor to suggest links between the operation of reactor’s subsystems and seismoacoustic signals. We demonstrate that seismoacoustic monitoring of an industrial facility can identify and track some industrial processes and detect events related to operations that involve energy transport.

ENHS reactor power level enhancement possibilities

2008 ◽  
Vol 50 (2-6) ◽  
pp. 279-285
Author(s):  
Arnaud Susplugas ◽  
Ehud Greenspan
Keyword(s):  
Power Level ◽  
Reactor Power

Investigations on Transonic Flow of Super-Critical CO2 Through Carbon Ring Seals

2015 ◽  
Author(s):  
Eike Hylla ◽  
Markus Schildhauer ◽  
Richard Büssow ◽  
Kolja Metz ◽  
Robert Klawes
Keyword(s):  
Test Procedure ◽  
Measured Data ◽  
Temperature Deformation ◽  
Experimental Investigations ◽  
Real Gas ◽  
Real Gas Effect ◽  
Flow Through ◽  
Co2 Flow ◽  
Gas Effect ◽  
Good Agreement

This paper gives an overview of numerical and experimental investigations on super-critical CO2 flow through carbon floating ring seals (CRS). The established simulation model considers the real gas effect, temperature deformation and the shaft rotation. For validation extensive measurements of the leakage rates, pressures and temperatures at various positions within the seal were conducted on a compressor prototype. Details of the measurement setup and the test procedure are given. The experimental results are discussed. A comparison of the measured data to the model prediction shows an overall good agreement.

In vivo total antioxidant capacity: comparison of two different analytical methods

2004 ◽  
Vol 42 (1) ◽  
Author(s):  
Cristina Vassalle ◽  
Silvano Masini ◽  
Clara Carpeggiani ◽  
Antonio L'Abbate ◽  
Claudio Boni ◽  
...  
Keyword(s):  
Uric Acid ◽  
Antioxidant Capacity ◽  
Lower Limit ◽  
Analytical Methods ◽  
Total Antioxidant Capacity ◽  
Mean Value ◽  
Wide Concentration Range ◽  
Plasma Samples ◽  
Frap Assay ◽  
Total Antioxidant

AbstractSeveral methods to assess the total antioxidant capacity (TAC) are available. However, the final value of measured TAC in the sample depends on the procedure used in every specific assay. This makes crucial the comparison of different analytical methods. The aim of our study was to evaluate analytical characteristics and laboratory reliability of two different assays: the ferric-reducing ability (FRAP) assay and a new spectrophotometric test (OXY-adsorbent test, Diacron, Italy).Unselected outpatients referred to the Institute of Clinical Physiology were studied (n=187, 58 females, 129 males, mean age: 65±13 years). All blood samples were maintained on ice, centrifuged within 15 minutes after blood collection and then stored at −80°C until performance of assay procedures.OXY assay: The lower limit of sensitivity was 6 μmol HClO/ml. The assay was found to be linear up to 440 μmol HClO/ml (r=−0.99, p<0.001). Absorbance was linear over a wide concentration range with solutions containing uric acid in purified form (0–1000 μmol/l, r=−0.996, p<0.001), serum (r=−0.99, p<0.01) or plasma serially diluted (r=−0.99, p<0.01). Mean value in plasma samples accounted for 366.2±7.2 μmol HClO/ml. Mean OXY value in females (353.4±13.2 mmol HClO/ml) was not different from that detected in males (372±8.6 mmol HClO/ml). A significant difference was observed between subjects without and with hypertension in serum OXY levels (344.8±9.9 and 383.2±10 μmol HClO/ml, p<0.01, respectively).FRAP assay: The lower limit of sensitivity was 15 μmol/l. Linearity was observed up to 1000 μmol/l (r=−0.998, p<0.001). Absorbance was linear over a wide concentration range with solutions containing uric acid in purified form (0–1000 μmol/l, r=0.997, p<0.001), serum (r=0.99, p<0.01) or plasma serially diluted (r=0.99, p<0.01). FRAP mean value in plasma samples, evaluated in 102 patients, accounted for 514.1±19.1 μmol/l. Mean FRAP in females (469±22.5 μmol/l) was not different from that detected in males (535±25.6 mmol/l).FRAP vs. OXY: A significant direct relationship was observed when comparing FRAP with OXY levels in the whole population (r=0.22, p<0.05).Neither of the methods are expensive and they are speedy and simple to perform. Values are reproducible and linearly correlated to the concentration of antioxidants present in the samples. For this reason, these methods may be considered practicable indicators of total antioxidant capacity, for routinely potential use in every laboratory and useful in all the studies concerning the evaluation of oxidative stress.

scholarly journals Feasibility study of the university of Utah TRIGA reactor power upgrade - part II: Thermohydraulics and heat transfer study in respect to cooling system requirements and design

2013 ◽  
Vol 28 (4) ◽  
pp. 352-361
Author(s):  
Philip Babitz ◽  
Dongok Choe ◽  
Tatjana Jevremovic
Keyword(s):  
Heat Transfer ◽  
Cooling System ◽  
Power Level ◽  
Flow Simulation ◽  
Nucleate Boiling ◽  
Reactor Power ◽  
Convection Current ◽  
Triga Reactor ◽  
Higher Power ◽  
The University

The thermodynamic conditions of the University of Utah's TRIGA Reactor were simulated using SolidWorks Flow Simulation, Ansys, Fluent and PARET-ANL. The models are developed for the reactor's currently maximum operating power of 90 kW, and a few higher power levels to analyze thermohydraulics and heat transfer aspects in determining a design basis for higher power including the cost estimate. It was found that the natural convection current becomes much more pronounced at higher power levels with vortex shedding also occurring. A departure from nucleate boiling analysis showed that while nucleate boiling begins near 210 kW it remains in this state and does not approach the critical heat flux at powers up to 500 kW. Based on these studies, two upgrades are proposed for extended operation and possibly higher reactor power level. Together with the findings from Part I studies, we conclude that increase of the reactor power is highly feasible yet dependable on its purpose and associated investments.

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