Pacific Northwest Laboratory Research Articles

Part 2:Validation for line lists generated for nitric acid (H14N16O3) for the ν1 band and its first two associated hot bands (ν1+ν9-ν9, ν1+ν7-ν7) in the 2.8 μm region, the ν1-ν9, ν1+ν9 and ν1+ν7 bands at 3.2 μm, 2.5 μm and 2.4 μm, respectively

This is the second of two back-to-back works, whose goal is to generate line lists for the ν1 band (3551.766 cm−1) and for the ν1+ν9-ν9 and ν1+ν7-ν7 hot bands for HNO3 in the 2.8 μm region. Also, we computed line lists for the weaker ν1-ν9, ν1+ν9, and ν1+ν7 bands, centered at 3093.53 cm−1, 4006.97 cm−1 and 4127.78 cm−1, respectively. While the first paper (Ref.[1], the preceding article in this issue), here labeled as “Part-1”, was devoted to the description of the determination of the needed spectroscopic parameters in term of line positions and intensities, this paper describes the resulting line lists and the validation process. For this task, we use laboratory spectra recorded at high resolution and described in Part-1, together with the cross-sections established by the Pacific Northwest Laboratory at low resolution. Also, we use high resolution stratospheric solar occultation spectra recorded by the MkIV balloon-borne instrument of the NASA Jet Propulsion Laboratory (JPL). Similar inter-comparisons with laboratory or atmospheric spectra are also performed using the pseudo-line-list generated at JPL in 2005 and with the ab initio ExoMol list calculated by the University College of London. It proves that the line list generated during this work provides significant better agreements between observed and computed spectra.

Analysis of the Wind Resources in Saharan Atlas of Algeria: Adrar Region as a Case Study

An objective analysis of the wind atlas map of the region of Adrar (Algeria) at a height of 10 meters above ground is essential, in order to classify these velocities according to the Pacific Northwest Laboratory (PNL) classification, and then to develop the separation velocity map. The present work is conducted in the region of Adrar to determine the monthly, seasonal, and annual energy generated by the Whisper200 wind turbine by using the Rayleigh distribution and the wind data recorded every three hours from January 1st, 1961 to December 31st, 2018. From the obtained findings, the northeast region of Adrar is a suitable region for wind applications. The surface of this area is equal to 16587 km², where two sites are located (Kaberten and Aougroute). However, the second PNL class is divided into seven zones. The wind speed in this region (2nd PNL class) is favourable for the setup of isolated wind turbines or hybrid systems. The following cities are located in this region (2nd PNL class): Adrar, Aoulef, Bordj Baji Mokthar, Timaiaouine, Regagne, and Timimoune.

Cell-Free Biocatalysis for the Production of Platform Chemicals

Genetically engineered host bacteria have an extensive history for the production of specific proteins including the synthesis of single enzymes for the modification of compounds produced for industrial purposes by biological or chemical processes. Such processes have been developed largely through the process of discovery. The ability to assemble multiple enzymes into synthetic pathways is a new development aided by the synthetic biology approach of constructing and assembling suitable enzymes into pathways that may or may not occur in Nature to provide a high-impact platform for bio-manufacturing of chemicals, biofuels and pharmaceuticals. Industry has depended on chemical catalysts because of the known constraints experienced frequently with biological catalysts but when high stereochemistry, mild synthesis conditions and environmentally friendly processes are significant, application of enzymes is preferred, especially in the case of drug synthesis where enantioselectivity is important. However, many whole cell production processes are beset by toxicity problems, metabolite competition, the production of side products, sub-optimal enzyme ratios and varying temperature optima. As a result, a cell-free biocatalysis allows the manipulation of substrate ratios, provision of regenerated cofactors and adjustment of high energy flux ratios that are difficult or impossible to control in whole cell synthesis. We discuss here the construction of cell free biocatalytic pathways as added free enzymes or multi-enzyme modules that may contain heterologous catalysts. We examine the status of applications leading to commercialisation, emphasizing the importance of economical cofactor regeneration. Nevertheless, problems remain, particularly protein post-translational modifications including glycosylation, phosphorylation, ubiquination, acetylation, proteolysis, etc. The National Renewable Energy Laboratory and Pacific North West Laboratory have published lists of top value-added chemicals from biomass that include glucaric acid. There have been few reports on the combination of synthetic biology and cell-free protein synthesis to set up pathways for these valuable intermediate compounds. This observation is despite the existence of at least one large scale but specialised cell-free production of antibody conjugates. This review will provide a description of one successful attempt at the cell-free production of glucaric acid and will evaluate progress for other key intermediate and platform chemicals.

Airborne Release Fractions from Surrogate Nuclear Waste Fires Containing Lanthanide Nitrates and Depleted Uranium Nitrate in 30% Tributyl Phosphate in Kerosene

Airborne contaminants from fires containing nuclear waste represent significant health hazards and shape the design and operation of nuclear facilities. Much of the data used to formulate DOE-HDBK-3010-94, “Airborne Release Fractions/Rates and Respirable Fractions for Nonreactor Nuclear Facilities,” from the U.S. Department of Energy, were taken over 40 years ago. The objectives of this study were to reproduce experiments from Pacific Northwest Laboratories conducted in June 1973 employing current aerosol measurement methods and instrumentation, develop an enhanced understanding of particulate formation and transport from fires containing nuclear waste, and provide modeling and experimental capabilities for updating current standards and practices in nuclear facilities. A special chamber was designed to conduct small fires containing 25 mL of flammable waste containing lutetium nitrate, ytterbium nitrate, or depleted uranium nitrate. Carbon soot aerosols showed aggregates of primary particles ranging from 20 to 60 nm in diameter. In scanning electron microscopy, ~200-nm spheroidal particles were also observed dispersed among the fractal aggregates. The 200-nm spherical particles were composed of metal phosphates. Airborne release fractions (ARFs) were characterized by leaching filter deposits and quantifying metal concentrations with mass spectrometry. The average mass-based ARF for 238U experiments was 1.0 × 10−3 with a standard deviation of 7.5 × 10−4. For the original experiments, DOE-HDBK-3010-94 states, “Uranium ARFs range from 2 × 10−4 to 3 × 10−3, an uncertainty of approximately an order of magnitude.” Thus, current measurements were consistent with DOE-HDBK-3010-94 values. ARF values for lutetium and ytterbium were approximately one to two orders of magnitude lower than 238U. Metal nitrate solubility may have varied with elemental composition and temperature, thereby affecting ARF values for uranium surrogates (Yb and Lu). In addition to ARF data, solution boiling temperatures and evaporation rates can also be deduced from experimental data.

Predicting the stochastic aerodynamic loads on blades of two yawed downwind hawts in uncontrolled conditions using a bem algorithm

Accurate predictions of the cycle-to-cycle variations in aerodynamic loads on wind turbine blades are important for estimating the life cycle costs of new wind power plants. Physical modelling of wind turbine systems is usually based on the average values of the aerodynamic parameters in the design process which would eliminate some important physical phenomena associated with the unsteady flows over the rotating blades. This paper presents a new algorithm implemented in a Blade Element Momentum (BEM) model to predict the cycle-to-cycle variations in the aerodynamic loads over multiple rotor rotations (cycles) for yawed rotors operating in natural flow conditions. In this approach, simulation theory developed by the Pacific Northwest Laboratories (PNL) is used to generate input turbulent wind speed time series on the whole rotor disc of two three-bladed downwind horizontal axis wind turbine (NREL Phase II and III) rotors. The unsteady influences of the dynamic stall kinematics and tower shadow are also considered in the current algorithm along with the phenomenon of stall delay. Predictions from the unsteady BEM model are compared to measured results and conclusions are drawn about the ability of the model to accurately simulate blade response to turbulence.

Analysis of Powder Airborne Release Fractions for Vessel Ruptures

The Department of Energy (DOE) handbook for airborne releases from nonreactor nuclear facilities bases its bounding airborne release fraction (ARF) for pressurized powders on tests conducted at Pacific Northwest Laboratory (PNL). An analysis is presented that correlates the ARF from these tests. The amount of powder that becomes airborne is correlated in terms of an adjusted airborne release fraction (AARF) equal to the product of the powder entrainment from the powder bed and the ratio of the total vessel volume to the volume occupied by the powder bed. Powder entrainments and release fractions at low pressures are correlated using a fluidized bed analogy. The analysis shows that the entrainment is enhanced by a sonic shock if the pressure prior to the rupture exceeds approximately 0.329 MPa (33 psig). A secondary, three-dimensional shock is predicted to occur at an initial pressure of approximately 2.39 MPa (332 psig). A correlation based on this analysis is used to predict the ARF for ruptures of vessels containing plutonium oxide. It is assumed that the oxide is pressurized by hydrogen that is radiolytically generated from adsorbed moisture.

Assessing wind energy potential for electricity generation using WECS in eight selected stations of Ethiopia

ABSTRACTWind utilisation for effective electricity generation has dated since last two decades by means of the modern wind turbines and has proved as a mature, reliable and efficient technology. This paper integrates the wind characteristics and performance of selected wind energy conversion systems (WECSs) from eight selected stations within Tigray region in Ethiopia. The wind speed data were collected over a period between 2002 and 2014. Based on the Pacific Northwest Laboratory (PNL) classification, all the selected stations fall into Class 1. Therefore, these stations may be advised for small-scale power applications. Furthermore, the highest annual energy output achieved was 3902.31 MWh using VESTAS V110 – 2.0 at Mekele.

Wind energy potential and economic evaluation of WPS using WECSs in three selected locations of Northern Ethiopia

This paper analyzes wind energy potential and economic evaluation of water pumping system (WPS) employed by various wind energy conversion systems (WECSs). The wind speed data gathered from three different locations of Northern Ethiopia are analyzed using the Weibull probability density function. The performance of small- to medium-sized commercial wind turbine models of various rated powers ranging between 25 and 2000 kW are analyzed. Economic evaluation of WPS (used in various WECSs) is performed using present value of cost (PVC) approach. According to the Pacific Northwest Laboratories (PNL) wind resources classification scheme, all the selected locations fall into the Class 1 category; hence they can be considered marginally for water pumping and small-scale electricity generation. It is noted that the POLARIS P 12–25 and the POLARIS P 15–50 are the most economical options for electricity generation and water pumping applications in the region.

Battelle contract renewed to operate Pacific Northwest laboratory

But DOE wants the contractor to reach out to regional universities and to bring more diversity to the lab’s staff.

The Mayak Worker Dosimetry System (MWDS-2013): A Bayesian Analysis to Quantify Pulmonary Binding of Plutonium in Lungs Using Historic Beagle Dog Data

The revised human respiratory tract model, published in Part 1 of the International Commission on Radiological Protection's (ICRP) report on Occupational Intakes of Radionuclides (OIR), includes a bound fraction, fb, to represent radionuclides that have become chemically bound in the lungs following dissolution of particulates in lung fluid. Bound radionuclides are not subject to particle transport clearance but can be absorbed to blood at a rate, sb. The occurrence of long-term binding of plutonium can greatly increase lung doses, particularly if it occurs in the bronchial and bronchiolar regions. However, there has been little evidence that currently supports the existence of a long-term bound state for plutonium. The present work describes the analysis of measurements of lung data obtained from a life span study of Beagle dogs that were exposed by inhalation to different concentrations of plutonium-239 (239Pu) nitrate aerosol at Pacific Northwest Laboratories, USA. The data have been analysed to assess whether a bound state was required to explain the data. A Bayesian approach was adopted for the analysis that accounts for uncertainties in model parameter values, including uncertainties in the rates of particle transport clearance. Furthermore, it performs the analysis using two different modelling hypotheses: a model based on the current ICRP human respiratory tract model and its treatment of alveolar particle transport clearance; and a model of particle transport clearance that is based on the updated model developed by ICRP to calculate dose coefficients for the OIR. The current model better represents clearance in dogs at early times (up to 1 year following intake) and the latter better represents retention at greater times (>5 years following intake). The results indicate that a long-term bound fraction of between 0.16 and 1.1%, with a mean value of between 0.24 and 0.8% (depending on the model) is required to explain the data.

Evaluation of thermal hydraulic safety of a nuclear fuel assembly in a mast assembly of nuclear power plant

We investigated the thermal–hydraulic safety of spent fuel bundles installed in a mast assembly, assuming a lock-up accident of a fuel transfer system. For this, flow analysis with Computational Fluid Dynamics (CFD) for the natural convection and subsequent safety evaluation with 1-D Nuclear Power Plant (NPP) safety analysis code were carried out. Prior to the natural convection analysis for the mast assembly using CFD code, we performed benchmark calculations against two experimental data sets obtained by Betts and Bokhari (2000) and PNL (Pacific Northwest Laboratory, 1980). This was done to select the proper physical models for a natural convection flow analysis and to ensure the reliability of prediction of natural convection flow in the fuel bundle geometry. Finally, we performed a main natural convection analysis for the fuel assembly inside the mast assembly. From this calculation, we observed a stable natural circulation flow between the mast assembly and pool side, and obtained coolant velocity at the inlet of the spent fuel bundle. This flow condition is given as a boundary condition for the 1-D NPP safety analysis code, which is used to predict the Critical Heat Flux and then departure from the nucleate boiling ratio.

수치해석을 이용한 마스트집합체 내 핵연료 집합체의 열수력적 안전성 연구

In this study, we conducted study on the confirmation of thermal-hydraulic safety for Mast assembly with Computational Fluid Dynamics(CFD) analysis. Before performing the natural convection analysis for the Mast assembly by using CFD code, we validated the CFD code against two benchmark natural convection data for the evaluation of turbulence models and confirmation of its applicability to the natural convection flow. From the first benchmark test which was performed by Betts et al. in the simple rectangular channel, we selected standard k-omega turbulence model for natural convection. And then, calculation performance of CFD code was also investigated in the sub-channel of rod bundle by comparing with PNL(Pacific Northwest Laboratory) experimental data and prediction results by MATRA and Fluent 12.0 which were performed by Kwon et al.. Finally, we performed main natural convection analysis for fuel assembly inside the Mast assembly by using validated turbulence model. From the calculation, we observed stable natural circulation flow between the mast assembly and pool side and evaluated the thermal-hydraulic safety by calculating the departure from nucleate boiling ratio.

Economic feasibility of developing wind turbines in Aligoodarz, Iran

This study evaluates the economic feasibility of electricity generation using wind turbines in city of Aligoodarz situated in the west part of Iran. For this purpose, the wind energy potential and its characteristics were assessed in terms of diurnal, monthly and annual analysis using five years measured wind speed data from 2005 to 2009 at 10m height. The analysis results specified a nearly stable wind pattern in different hours and months of the year which demonstrated more suitability of the region for wind energy harnessing to meet the electricity demand in all time intervals throughout the year. According to Pacific Northwest Laboratory (PNL) wind power classification, the wind resource in Aligoodarz falls in class 3 and the location was recognized as a moderate location for wind energy development. The economic feasibility of six different wind turbines with rated powers ranging from 20 to 150kW was evaluated. Among all turbines examined, the E-3120 wind turbine was introduced as the most attractive option for installation.

History of Highly Enriched Uranium Production in Russia

Between 1949–1963, the Soviet Union built four large industrial uranium-enrichment plants. All initially used gaseous diffusion for isotope separation. Starting in 1964, however, the Soviet Union b...

Parameterization of aerosol dry deposition velocities onto smooth and rough surfaces

The velocities of aerosol deposition onto vertical and horizontal surfaces are needed for 2D and 3D calculations of aerosol transport and deposition in the urban and indoor environments. This paper analyzes the experimental results and semiempirical and theoretical models on dry deposition velocities. The features of the solution obtained by Zhao and Wu [(2006a). Modeling particle deposition from fully developed turbulent flow in ventilation duct. Atmospheric Environment, 40, 457–466] for the velocity of aerosol deposition onto smooth surfaces are analyzed, the integrals are approximated analytically. To treat the deposition onto rough surfaces, the results of Sehmel [(1973). Particle eddy diffusivities and deposition for isothermal flow and smooth surfaces. Journal of Aerosol Science, 4, 125–138]; Sehmel and Hodgson [(1978). A model for predicting dry deposition of particles and gases to environmental surfaces. PNL-SA-6721. Richland, WA: Battelle, Pacific Northwest Laboratory] are modified and represented in a unified manner for vertical and horizontal surfaces. Cross-comparison with data of Slinn [(1978) Parameterization for resuspension and for Wet and Dry Deposition of Particles and Gases for Use in Radiation Dose Calculations. Nucl.Safety, 19(2), 205–219.] and the model of Lai and Nazaroff [(2000). Modeling indoor particle deposition from turbulent flow onto smooth surfaces. Journal of Aerosol Science, 31, 463–476] allowed reconciliation between the theoretical and semiempirical approaches. Finally, an approximation to the aerosol dry deposition velocities is obtained in the form of convenient parameterization formulas covering a wide range of particle sizes 0.01 μ m ⩽ d ⩽ 1000 μ m and surface roughnesses z 0 ⩽ 10 cm .

Measuring relevant things

Performance ImprovementVolume 45, Issue 3 p. 33-37 Article Measuring relevant things D. Keith Denton PhD, D. Keith Denton PhD dkd848f@MissouriState.edu D. Keith Denton, PhD, is CEO of CIVID3 and Professor of Management at Missouri State University. As the author of 14 books and more than 150 articles, he has written extensively about improving process inefficiencies and decision making in both the service and manufacturing sectors. He is a frequent international consultant and seminar leader in the United States, Great Britain, New Zealand, and Australia. Keith is an international presenter. He recently conducted seminars on Horizontal Management to the top 100 government and corporate leaders in the Philippines. Among his honors is inclusion in recent editions of Who's Who in America and Who's Where Among Writers. Before teaching at Missouri State University, he taught at Southern Illinois University and worked for Union Carbide-Nuclear Division, Maryland Casualty Company, and others. Keith has provided consulting for Recreational Equipment Inc. in Sumner, Washington; J.B. Hunt Transport, Inc.; The Upjohn Company; Pacific Northwest Laboratories; The Cat's Pajamas; Mobil Oil Corporation; Building and Land Development Division of Parks, Planning and Resources Department in Bellevue, Washington; The Durham Company; University of Michigan Medical Center; Kraft General Foods; and Bon Secours of Michigan Health Care System, Inc.Search for more papers by this author D. Keith Denton PhD, D. Keith Denton PhD dkd848f@MissouriState.edu D. Keith Denton, PhD, is CEO of CIVID3 and Professor of Management at Missouri State University. As the author of 14 books and more than 150 articles, he has written extensively about improving process inefficiencies and decision making in both the service and manufacturing sectors. He is a frequent international consultant and seminar leader in the United States, Great Britain, New Zealand, and Australia. Keith is an international presenter. He recently conducted seminars on Horizontal Management to the top 100 government and corporate leaders in the Philippines. Among his honors is inclusion in recent editions of Who's Who in America and Who's Where Among Writers. Before teaching at Missouri State University, he taught at Southern Illinois University and worked for Union Carbide-Nuclear Division, Maryland Casualty Company, and others. Keith has provided consulting for Recreational Equipment Inc. in Sumner, Washington; J.B. Hunt Transport, Inc.; The Upjohn Company; Pacific Northwest Laboratories; The Cat's Pajamas; Mobil Oil Corporation; Building and Land Development Division of Parks, Planning and Resources Department in Bellevue, Washington; The Durham Company; University of Michigan Medical Center; Kraft General Foods; and Bon Secours of Michigan Health Care System, Inc.Search for more papers by this author First published: 17 August 2006 https://doi.org/10.1002/pfi.2006.4930450308Citations: 1 AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume45, Issue3March 2006Pages 33-37 RelatedInformation

The radon inverse dose rate effect and high-LET galactic hazards

The lung dose rate per unit 222Rn concentration in enclosed spaces is shown to experience transitions at high radon concentrations. This has implications on the radon inverse dose rate effect. At an air change rate (ACH) of 0.194 h(-1) and relative humidity (RH) of 52.3% in a 0.283 m3 test chamber, the total human lung dose for an adult male in a residential setting (breathing rate 0.78 m3 h(-1)) would undergo a reduction of 2.5 using the ICRP 66 human respiratory tract model and the BEIR VI methodology. Using the same methodology of both Cross (Pacific Northwest Laboratory rat exposures) and Lubin et al. (miners dose rates), adjustments are necessary for effects of RH and ACHs. These adjustments, however, do not affect the reduction behaviour. It is thus shown that the enhanced deposition effect (EDE) must influence the magnitude of the purported inverse dose rate effect (IDRE). In the analysis of animal data, Cross rat exposures in a 2.0 m3 chamber, a reduction in lung dose is estimated to be over a factor of 3 the transition between the 50 and 500 WLM week(-1) dose rate range. For an estimation of the EDE, using a hypothetical 30 m3 enclosure for underground miners, we obtain a factor of approximately 4 in human lung dose reduction. Although the extensive analyses required make these results qualitative, the EDE behaviour is sufficiently conclusive that these estimates show that the radon IDRE for lung cancer must be an EDE dosimetric issue as well as a radiological lung cell dose response issue. The consequence of analysis of other animal data would achieve the same conclusion.

Intranets. Bringing integration to performance measurement

Performance ImprovementVolume 44, Issue 4 p. 28-33 Article Intranets. Bringing integration to performance measurement D. Keith Denton PhD, D. Keith Denton PhD D. Keith Denton, PhD, is CEO of CIVID3. As the author of 14 books and more than 150 articles, he has written extensively about improving process inefficiencies and decision-making in both the service and manufacturing sectors. Keith is published in over six languages and is a frequent international consultant and seminar leader. Among his honors are inclusion in recent editions of “Who's Who in America,” and “Who's Where Among Writers.” Before teaching at Southwest Missouri State University, he taught at Southern Illinois University and worked for Union Carbide-Nuclear Division, Maryland Casualty Company, and others. He is an international presenter. Keith recently conducted seminars on Horizontal Management to the top 100 government and corporate leaders in the Philippines. He has provided consulting for Recreational Equipment Inc. in Sumner, Washington; J.B. Hunt Transport, Inc.; The Upjohn Company; Pacific Northwest Laboratories; The Cat's Pajamas; Mobil Oil Corporation; Building and Land Development Division of Parks, Planning and Resources Department in Bellevue, Washington; The Durham Company; University of Michigan Medical Center; Kraft General Foods; and Bon Secours of Michigan Health Care System, Inc. Keith may be reached at dkd848f@smsu.edu.Search for more papers by this author D. Keith Denton PhD, D. Keith Denton PhD D. Keith Denton, PhD, is CEO of CIVID3. As the author of 14 books and more than 150 articles, he has written extensively about improving process inefficiencies and decision-making in both the service and manufacturing sectors. Keith is published in over six languages and is a frequent international consultant and seminar leader. Among his honors are inclusion in recent editions of “Who's Who in America,” and “Who's Where Among Writers.” Before teaching at Southwest Missouri State University, he taught at Southern Illinois University and worked for Union Carbide-Nuclear Division, Maryland Casualty Company, and others. He is an international presenter. Keith recently conducted seminars on Horizontal Management to the top 100 government and corporate leaders in the Philippines. He has provided consulting for Recreational Equipment Inc. in Sumner, Washington; J.B. Hunt Transport, Inc.; The Upjohn Company; Pacific Northwest Laboratories; The Cat's Pajamas; Mobil Oil Corporation; Building and Land Development Division of Parks, Planning and Resources Department in Bellevue, Washington; The Durham Company; University of Michigan Medical Center; Kraft General Foods; and Bon Secours of Michigan Health Care System, Inc. Keith may be reached at dkd848f@smsu.edu.Search for more papers by this author First published: 09 February 2007 https://doi.org/10.1002/pfi.4140440408 AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume44, Issue4April 2005Pages 28-33 RelatedInformation

Thermodynamic considerations and prediction of the primary coolant activity of 99Tc

A physical model has been developed to describe the coolant activity behaviour of 99Tc, during constant and reactor shutdown operations. This analysis accounts for the fission production of technetium and molybdenum, in which their chemical form and volatility is determined by a thermodynamic treatment using Gibbs-energy minimization. The release kinetics are calculated according to the rate-controlling step of diffusional transport in the fuel matrix and vaporization from the fuel-grain surface. Based on several in-reactor tests with defective fuel elements, and as supported by the thermodynamic analysis, the model accounts for the washout of molybdenum from the defective fuel on reactor shutdown. The model also considers the recoil release of both 99Mo and 99Tc from uranium contamination, as well as a corrosion source due to activation of 98Mo. The model has provided an estimate of the activity ratio 99Tc/ 137Cs in the ion-exchange columns of the Darlington Nuclear Generating Station, i.e., 6 × 10 −6 (following ∼200 days of steady reactor operation) and 4 × 10 −6 (with reactor shutdown). These results are consistent with that measured by the Battelle Pacific Northwest Laboratories with a mixed-bed resin-sampling device installed in a number of Pressurized Water Reactor and Boiling Water Reactor plants.

Validation of the Continuous-Energy Monte Carlo Criticality-Safety Analysis System MVP and JENDL-3.2 Using the Internationally Evaluated Criticality Benchmarks

Validation of the continuous-energy Monte Carlo criticality-safety analysis system, comprising the MVP code and neutron cross sections based on JENDL-3.2, was examined using benchmarks evaluated in the “International Handbook of Evaluated Criticality Safety Benchmark Experiments.” Eight experiments (116 configurations) for the plutonium solution and plutonium-uranium mixture systems performed at Valduc, Battelle Pacific Northwest Laboratories, and other facilities were selected and used in the studies. The averaged multiplication factors calculated with MVP and MCNP-4B using the same neutron cross-section libraries based on JENDL-3.2 were in good agreement. Based on methods provided in the Japanese nuclear criticality-safety handbook, the estimated criticality lower-limit multiplication factors to be used as a subcriticality criterion for the criticality-safety evaluation of nuclear facilities were obtained. The analysis proved the applicability of the MVP code to the criticality-safety analysis of nuclear fuel facilities, particularly to the analysis of systems fueled with plutonium and in homogeneous and thermal-energy conditions.