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Advanced Neutron Source Dynamic Model (ANSDM) code description and user guide

Description: A mathematical model is designed that simulates the dynamic behavior of the Advanced Neutron Source (ANS) reactor. Its main objective is to model important characteristics of the ANS systems as they are being designed, updated, and employed; its primary design goal, to aid in the development of safety and control features. During the simulations the model is also found to aid in making design decisions for thermal-hydraulic systems. Model components, empirical correlations, and model parameters are discussed; sample procedures are also given. Modifications are cited, and significant development and application efforts are noted focusing on examination of instrumentation required during and after accidents to ensure adequate monitoring during transient conditions.
Date: August 1, 1995
Creator: March-Leuba, J.
Partner: UNT Libraries Government Documents Department

Performance requirements of the advanced neutron source reactor protection system

Description: Research reactors often have protection-systems performance requirements very different from those of commercial reactors. This paper discusses the special characteristics of the Advanced Neutron Source (ANS) reactor that control these requirements, and it presents some calculations used to quantify this performance.
Date: April 1, 1995
Creator: March-Leuba, J. & Battle, R.E.
Partner: UNT Libraries Government Documents Department

NERI PROJECT 99-119. TASK 1. ADVANCED CONTROL TOOLS AND METHODS. FINAL REPORT

Description: Nuclear plants of the 21st century will employ higher levels of automation and fault tolerance to increase availability, reduce accident risk, and lower operating costs. Key developments in control algorithms, fault diagnostics, fault tolerance, and communication in a distributed system are needed to implement the fully automated plant. Equally challenging will be integrating developments in separate information and control fields into a cohesive system, which collectively achieves the overall goals of improved performance, safety, reliability, maintainability, and cost-effectiveness. Under the Nuclear Energy Research Initiative (NERI), the U. S. Department of Energy is sponsoring a project to address some of the technical issues involved in meeting the long-range goal of 21st century reactor control systems. This project, ''A New Paradigm for Automated Development Of Highly Reliable Control Architectures For Future Nuclear Plants,'' involves researchers from Oak Ridge National Laboratory, University of Tennessee, and North Carolina State University. This paper documents a research effort to develop methods for automated generation of control systems that can be traced directly to the design requirements. Our final goal is to allow the designer to specify only high-level requirements and stress factors that the control system must survive (e.g. a list of transients, or a requirement to withstand a single failure.) To this end, the ''control engine'' automatically selects and validates control algorithms and parameters that are optimized to the current state of the plant, and that have been tested under the prescribed stress factors. The control engine then automatically generates the control software from validated algorithms. Examples of stress factors that the control system must ''survive'' are: transient events (e.g., set-point changes, or expected occurrences such a load rejection,) and postulated component failures. These stress factors are specified by the designer and become a database of prescribed transients and component failures. The candidate control systems ...
Date: September 9, 2002
Creator: March-Leuba, J.A.
Partner: UNT Libraries Government Documents Department

NERI PROJECT 99-119."A NEW PARADIGM FOR AUTOMATIC DEVELOPMENT OF HIGHLY RELIABLE CONTROL ARCHITECTURES FOR NUCLEAR POWER PLANTS."PHASE-1 PROGRESS REPORT

Description: This report describes the tasks performed and the progress made during Phase 1 of the DOE-NERI project number 99-119 entitled ''Automatic Development of Highly Reliable Control Architecture for Future Nuclear Power Plants''. This project is a collaboration effort between the Oak Ridge National Laboratory (ORNL,) The University of Tennessee, Knoxville (UTK) and the North Carolina State University (NCSU). ORNL is the lead organization and is responsible for the coordination and integration of all work. This research focuses on the development of methods for automated generation of control systems that can be traced directly to the design requirements for the life of the plant. Our final goal is to ''capture'' the design requirements inside a ''control engine'' during the design phase. This control engine is, then, not only capable of designing automatically the initial implementation of the control system, but it also can confirm that the original design requirements are still met during the life of the plant as conditions change. This control engine captures the high-level requirements and stress factors that the control system must survive (e.g. a list of transients, or a requirement to withstand a single failure). The control engine, then, is able to generate automatically the control-system algorithms and parameters that optimize a design goal and satisfy all requirements. As conditions change during the life of the plant (e.g. component degradation, or subsystem failures) the control engine automatically ''flags'' that a requirement is not satisfied, and it can even suggest a modified configuration that would satisfy it. This control engine concept is shown schematically in Fig. 1. The implementation of this ''control-engine'' design methodology requires the following steps, which are described in detail in the attachments to this report: (1) Selection of Design Requirements Related to Control System Performance; (2) Implementation of Requirements in Mathematical Form; (3) ...
Date: August 29, 2000
Creator: March-Leuba, J.A.
Partner: UNT Libraries Government Documents Department

Methodology for interpretation of fissile mass flow measurements

Description: This paper describes a non-intrusive measurement technique to monitor the mass flow rate of fissile material in gaseous or liquid streams. This fissile mass flow monitoring system determines the fissile mass flow rate by relying on two independent measurements: (1) a time delay along a given length of pipe, which is inversely proportional to the fissile material flow velocity, and (2) an amplitude measurement, which is proportional to the fissile concentration (e.g., grams of {sup 235}U per length of pipe). The development of this flow monitor was first funded by DOE/NE in September 95, and initial experimental demonstration by ORNL was described in the 37th INMM meeting held in July 1996. This methodology was chosen by DOE/NE for implementation in November 1996; it has been implemented in hardware/software and is ready for installation. This paper describes the methodology used to interpret the data measured by the fissile mass flow monitoring system and the models used to simulate the transport of fission fragments from the source location to the detectors.
Date: September 1, 1997
Creator: March-Leuba, J.; Mattingly, J.K. & Mullens, J.A.
Partner: UNT Libraries Government Documents Department

Sensitivity of BWR stability calculations to numerical integration techniques

Description: Computer simulations have shown that stability calculations in boiling water reactors (BWRs) are very sensitive to a number of input parameters, modeling assumptions, and numerical integration techniques. Following the 1988 LaSalle instability event, a significant industry-wide effort was invested in identifying these sensitivities. One major conclusion from these studies was that existing time-domain codes could best predict BWR stability by using explicit methods for the energy equation with a Courant number as close to unity as possible. This paper presents a series of sensitivity studies using simplified models, which allow us to determine the effect that different numerical integration techniques have on the results of stability calculations. The present study appears to indicate that, even though using explicit integration with a Courant number of one is adequate for existing codes using time-integration steps of less than 10 ms, second-order solution techniques for the time integration can result in significant improvements in the accuracy of linear (i.e., decay ratio) stability calculations.
Date: November 1, 1997
Creator: Peiro, D. G. & March-Leuba, J.
Partner: UNT Libraries Government Documents Department

Calibration measurements using the ORNL fissile mass flow monitor

Description: This paper presents a demonstration of fissile-mass-flow measurements using the Oak Ridge National Laboratory (ORNL) Fissile Mass Flow Monitor in the Paducah Gaseous Diffusion Plant (PGDP). This Flow Monitor is part of a Blend Down Monitoring System (BDMS) that will be installed in at least two Russian Federation (R.F.) blending facilities. The key objectives of the demonstration of the ORNL Flow Monitor are two: (a) demonstrate that the ORNL Flow Monitor equipment is capable of reliably monitoring the mass flow rate of {sup 235}UF{sub 6} gas, and (b) provide a demonstration of ORNL Flow Monitor system in operation with UF{sub 6} flow for a visiting R.F. delegation. These two objectives have been met by the PGDP demonstration, as presented in this paper.
Date: November 1, 1998
Creator: March-Leuba, J.; Uckan, T.; Sumner, J.; Mattingly, J. & Mihalczo, J.
Partner: UNT Libraries Government Documents Department

Commissioning Measurements and Experience Obtained from the Installation of a Fissile Mass Flow monitor in the URAL Electrochemical Integrated Plant (UEIP) in Novouralsk

Description: The Blend Down Monitoring System (BDMS) equipment sent earlier to the Ural Electrochemical Integrated Plant (UEIP) at Novouralsk, Russia, was installed and implemented successfully on February 2, 1999. The BDMS installation supports the highly enriched uranium (HEU) Transparency Implementation Program for material subject to monitoring under the HEU purchase agreement between the United States of America (USA) and the Russian Federation (RF). The BDMS consists of the Oak Ridge National Laboratory (ORNL) Fissile (uranium-235) Mass Flow Monitor (FMFM) and the Los Alamos National Laboratory (LANL) Enrichment Monitor (EM). Two BDMS�s for monitoring the Main and Reserve HEU blending process lines were installed at UEIP. Independent operation of the FMFM Main and FMFM Reserve was successfully demonstrated for monitoring the fissile mass flow as well as the traceability of HEU to the product low enriched uranium. The FMFM systems failed when both systems were activated during the calibration phase due to a synchronization problem between the systems. This operational failure was caused by the presence of strong electromagnetic interference (EMI) in the blend point. The source-modulator shutter motion of the two FMFM systems was not being properly synchronized because of EMI producing a spurious signal on the synchronization cable connecting the two FMFM cabinets. The signature of this failure was successfully reproduced at ORNL after the visit. This unexpected problem was eliminated by a hardware modification and software improvements during a recent visit (June 9-11, 1999) to UEIP, and both systems are now operating as expected.
Date: July 25, 1999
Creator: March-Leuba, J.; Mastal, E.; Powell, D.; Sumner, J.; Uckan, T. & Vines, V.
Partner: UNT Libraries Government Documents Department

Physics design of fissile mass-flow monitoring system

Description: The system measures the flow rate and uranium-235 content in liquid or gas streams; it does not penetrate the process piping. A moderated fission neutron source is used to periodicially introduce a burst of thermal neutrons into the fluid stream to induce fission; delayed gamma emissions from the resulting fission fragments are detected by high-efficiency scintillators downstream of the neutron source. The fluid flow rate is measure from the time between initiation of the thermal neutron burst and detection of the fission product gamma emissions, and the U-235 content is inferred from the intensity of the gamma burst detected. Design of the fissile mass flow monitor requires satisfaction of several competing constraints. Efficient operation of the monitor requires that source-induced fission rate and detection efficiency be maximized while the source-induced background rate is simultaneoulsy minimized. Near optical nuclear design of the system was achieved using numerous Monte Carlo calculations and measurements. This paper addresses calculational aspects of the physics design for the system applied to UF{sub 6} gas.
Date: September 1, 1997
Creator: Mattingly, J.K.; March-Leuba, J.; Valentine, T.E.; Mihalczo, J.T. & Uckan, T.
Partner: UNT Libraries Government Documents Department

Hardware implementation of the ORNL fissile mass flow monitor

Description: This paper provides an overall description of the implementation of the Oak Ridge National Laboratory (ORNL) Fissile Mass Flow Monitor, which is part of a Blend Down Monitoring System (BDMS) developed by the US Department of Energy (DOE). The Fissile Mass Flow Monitor is designed to measure the mass flow of fissile material through a gaseous or liquid process stream. It consists of a source-modulator assembly, a detector assembly, and a cabinet that houses all control, data acquisition, and supporting electronics equipment. The development of this flow monitor was first funded by DOE/NE in September 95, and an initial demonstration by ORNL was described in previous INMM meetings. This methodology was chosen by DOE/NE for implementation in November 1996, and the hardware/software development is complete. Successful BDMS installation and operation of the complete BDMS has been demonstrated in the Paducah Gaseous Diffusion Plant (PGDP), which is operated by Lockheed Martin Utility Services, Inc. for the US Enrichment Corporation and regulated by the Nuclear Regulatory Commission. Equipment for two BDMS units has been shipped to the Russian Federation.
Date: November 1, 1998
Creator: McEvers, J.; Sumner, J.; Jones, R.; Ferrell, R.; Martin, C.; Uckan, T. et al.
Partner: UNT Libraries Government Documents Department

Source modulation-correlation measurement for fissile mass flow in gas or liquid fissile streams

Description: The method of monitoring fissile mass flow on all three legs of a blending point, where the input is high-enriched uranium (HEU) and low-enriched uranium (LEU) and the product is PEU, can yield the fissile stream velocity and, with calibration, the [sup235]U content. The product of velocity and content integrated over the pipe gives the fissile mass flow in each leg. Also, the ratio of fissile contents in each pipe: HEU/LEU, HEU/PEU, and PEU/LEU, are obtained. By modulating the source on the input HEU pipe differently from that on the output pipe, the HEU gas can be tracked through the blend point. This method can be useful for monitoring flow velocity, fissile content, and fissile mass flow in HEU blenddown of UF[sub 6] if the pressures are high enough to contain some of the induced fission products. This method can also be used to monitor transfer of fissile liquids and other gases and liquids that emit radiation delayed from particle capture. These preliminary experiments with the Oak Ridge apparatus show that the method will work and the modeling is adequate.
Date: September 1, 1996
Creator: Mihalczo, J.T.; March-Leuba, J.A.; Valentine, T.E.; Abston, R.A.; Mattingly, J.K. & Mullens, J.A.
Partner: UNT Libraries Government Documents Department

Fissile Mass Flow Monitor Implementation for Transparency in HEU Blenddown at the URAL Electrochemical Integrated Plant (UEIP) in Novouralsk

Description: The Oak Ridge National Laboratory (ORNL) Fissile Mass Flow Monitor (FMFM) was deployed at the Ural Electrochemical Integrated Plant (UEIP) highly enriched uranium (HEU) blending facility in January and February 1999 at Novouralsk in Russia for the DOE HEU Transparency Program. The FMFM provides unattended monitoring of the fissile mass flow of the uranium hexafluoride (UF{sub 6}) gas in the process lines of HEU, the low enriched uranium (LEU) blend stock, and the product LEU (P-LEU) of the blending tee non-intrusively. To do this, uranium-235 (U-235) fissions are induced in the UF{sub 6} by a thermalized and modulated californium-252 (Cf-252) neutron source placed on each process line. A set of detectors, located downstream of source, measure delayed gamma rays emitted by the resulting fission fragments. The observed delay in the time correlated measurement between the source and the detector signal provides the velocity of UF{sub 6} and its amplitude is related to the U- 235 content in UF{sub 6}. An on-line computer controls the source modulator, processes the collected detector data, and displays the results. The UEIP Main and the Reserved process lines were implemented with minor modifications. The FMFM monitors the HEU blending operation by measuring UF{sub 6} flows in the process blending lines, and the traceability of the HEU flow from the blend point to the P-LEU. The detail operational characteristics of the FMFM software (FM2) and the measurement methodology used are presented.
Date: July 25, 1999
Creator: March-Leuba, J.; Mastal, E.; Powell, D.; Sumner, J.; Uckan, T. & Vines, B.
Partner: UNT Libraries Government Documents Department

PASSIVE NMIS MEASUREMENTS TO ESTIMATE SHAPE OF PLUTONIUM ASSEMBLIES (SLIDE PRESENTATION)

Description: The purpose of this work is to estimate shape of plutonium assemblies using new signatures acquired by passive NMIS measurements (no external source). Applications include identification of containerized regular shapes of plutonium, identification by shape without template, verification of shape for template initialization, and potential utility for estimating shape of holdup in plutonium processing facilities. To illustrate the technique and test its feasibility, laboratory measurements have been performed with californium spontaneous fission sources as a surrogate for plutonium. Advantages of the technique include the following: passive (requires no external source for plutonium measurements), stationary (no scanning of the assembly is required), penetrative (shape is estimated from neutron emissions), obscurable (spatial resolution can be deliberately degraded by changing detector size and/or timing resolution), inexpensive (majority of NMIS components are commercial products), portable (detection system is transported to the item, not vice versa). It is concluded that passive NMIS measurements can infer the mass of plutonium assemblies: NMIS correlations scale directly with spontaneous fission rate (Pu-240); NMIS correlations scale with fissile mass (Pu-239) and multiplication. New third-order correlations can estimate the shape of fission sources (Pu-240 & Pu-239) from passive measurements. Surrogate measurements of californium spontaneous fission sources have demonstrated the feasibility of this concept. Measurements of various shapes of plutonium are necessary to continue the development of this technique.
Date: November 25, 1998
Creator: MARCH-LEUBA, J.A.; MATTINGLY, J.K.; MIHALCZO, J.T.; PEREZ, R.B. & VALENTINE, T.E.
Partner: UNT Libraries Government Documents Department

UF{sub 6} fissile mass flow simulation at Oak Ridge National Laboratory

Description: Basis for measuring fissile mass flow in slurries, liquid, and gaseous streams is activation of a fissile stream by neutrons and then detection of delayed radiation from resulting fission products. This paper describes recent simulation measurements with the first prototype of the system for fissile mass flow measurements with HEU UF{sub 6} gas for use in blenddown facilities. Theory was only 15% higher than actual measured; thus calibration factor would be 0.85. This simulation of HEU gas flow confirms well the understanding of the physical phenomena associated with this measurement system.
Date: August 1, 1997
Creator: Mihalczo, J.T.; March-Leuba, J.; Valentine, T.E.; Mattingly, J.K.; Uckan, T. & McEvers, J.A.
Partner: UNT Libraries Government Documents Department

The Blend Down Monitoring System Demonstration at the Paducah Gaseous Diffusion Plant

Description: Agreements between the governments of the US and the Russian Federation for the US purchase of low enriched uranium (LEU) derived from highly enriched uranium (HEU) from dismantled Russian nuclear weapons calls for the establishment of transparency measures to provide confidence that nuclear nonproliferation goals are being met. To meet these transparency goals, the agreements call for the installation of nonintrusive US instruments to monitor the down blending of HEU to LEU. The Blend Down Monitoring System (BDMS) has been jointly developed by the Los Alamos National Laboratory (LANL) and the Oak Ridge National Laboratory (ORNL) to continuously monitor {sup 235}U enrichments and mass flow rates at Russian blending facilities. Prior to its installation in Russian facilities, the BDMS was installed and operated in a UF{sub 6} flow loop in the Paducah Gaseous Diffusion Plant simulating flow and enrichment conditions expected in a typical down-blending facility. A Russian delegation to the US witnessed the equipment demonstration in June, 1998. To conduct the demonstration in the Paducah Gaseous Diffusion Plant (PGDP), the BDMS was required to meet stringent Nuclear Regulatory Commission licensing, safety and operational requirements. The Paducah demonstration was an important milestone in achieving the operational certification for the BDMS use in Russian facilities.
Date: July 25, 1999
Creator: Benton, J.; Close, D.; Johnson, W., Jr.; Kerr, P.; March-Leuba, J.; Mastal, E. et al.
Partner: UNT Libraries Government Documents Department

Passive NMIS Measurements to Estimate the Shape of Plutonium Assemblies

Description: A new technique to estimate the shape attribute of plutonium assemblies using the Nuclear Materials Identification System (NMIS) is described. The proposed method possesses a number of advantages. It is passive no external radiation source is required to estimate the shape of plutonium assemblies. Instead, inherent gamma and neutron emissions from spontaneous fission of {sup 240}Pu and subsequent induced fission of {sup 239}Pu are detected to estimate the shape attribute. The technique is also stationary: shape is estimated without scanning the assembly by moving the detectors relative to the assembly. The proposed method measures third order correlations between triplets of gamma/neutron-sensitive detectors. The real coincidence of a pair of gammas is used as a ''trigger'' to approximately identify the time of a spontaneous or induced fission event. The spatial location of this fission event is inferred from the real coincidence of a subsequent neutron with the initial pair of correlated gammas by using the neutron's time-of-flight (approximately the delay between the gamma pair and the neutron) and the fission neutron spectra of {sup 240}Pu and {sup 239}Pu. The spatial distribution of fission sites and hence the approximate shape of the plutonium assembly is thereby inferred by measuring the distribution of a large number of these correlated triplets. Proof-of-principle measurements were performed using {sup 252}Cf as a surrogate for {sup 240}Pu to demonstrate that the technique is feasible. For the simple shapes approximated with {sup 252}Cf sources, the measurements showed that the proposed method is capable of correctly identifying the shape and accurately estimating its size to within a few percent of actual.
Date: July 22, 1999
Creator: Mattingly, J.K.; Chiang, L.G.; March-Leuba, J.A.; Mihalczo, J.T.; Mullens, J.A.; Perez, R.B. et al.
Partner: UNT Libraries Government Documents Department