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Thermal-Hydraulic Bases for the Safety Limits and Limiting Safety System Settings for HFIR Operation at 100 MW and 468 psig Primary Pressure, Using Specially Selected Fuel Elements

Description: This report summarizes thermal hydraulic analyses performed to support HFIR operation at 100 MW and 468 psig pressure using specially selected fuel elements. The analyses were performed with the HFIR steady state heat transfer code, originally developed during HFIR design. This report addresses the increased core heat removal capability which can be achieved in fuel elements having coolant channel thicknesses that exceed the minimum requirements of the HFIR fuel fabrication specifications. Specific requirements for the minimum value of effective uniform as-built coolant channel thickness are established for fuel elements to be used at 100 MW. The burnout correlation currently used in the steady-state heat transfer code was also compared with more recent experimental results for stability of high-velocity flow in narrow heated channels, and the burnout correlation was found to be conservative with respect to flow stability at typical HFIR hot channel exit conditions at full power.
Date: September 1, 1998
Creator: Rothrock, R.B.
Partner: UNT Libraries Government Documents Department

Development of High Flux Isotope Reactor (HFIR) subcriticality monitoring methods

Description: Use of subcritical source multiplication measurements during refueling has been investigated as a possible replacement for out-of-reactor subcriticality measurements formerly made on fresh HFIR fuel elements at the ORNL Critical Experiment Facility. These measurements have been used in the past for preparation of estimated critical rod positions, and as a partial verification, prior to reactor startup, that the requirements for operational shutdown margin would be met. Results of subcritical count rate data collection during recent HFIR refuelings and supporting calculations are described illustrating the intended measurement method and its expected uncertainty. These results are compared to historical uses of the out-of-reactor core measurements and their accuracy requirements, and a planned in-reactor test is described which will establish the sensitivity of the method and calibrate it for future routine use during HFIR refueling. 2 refs., 1 fig., 2 tabs.
Date: January 1, 1991
Creator: Rothrock, R.B.
Partner: UNT Libraries Government Documents Department

HEDL W-1 SLSF experiment LOPI transient and boiling test results. [LMFBR]

Description: The W-1 Sodium Loop Safety Facility (SLSF) experiment was designed to study the heat release characteristics of fast reactor fuel pins under Loss-of-Piping-Integrity (LOPI) accident conditions and determine stable sodium boiling initiation and recovery limits in a prototypic fuel pin bundle array. The results of the experiment address major second level of assurance (LOA-2) safety issues and provide increased insight and understanding of phenomena that would inherently terminate hypothesized accidents with only limited core damage. The irradiation phase of the experiment, consisting of thirteen individual transients, was performed between May 27 and July 20, 1979. The final transient produced approximately two seconds of coolant boiling, cladding dryout, and incipient fuel pin failure. The facility and test hardware performed as designed, allowing completion of all planned tests and achievement of all test objectives.
Date: January 1, 1980
Creator: Henderson, J.M.; Wood, S.A. & Rothrock, R.B.
Partner: UNT Libraries Government Documents Department

High Flux Isotope Reactor power upgrade status

Description: A return to 100-MW operation is being planned for the High Flux Isotope Reactor (HFIR). Recent improvements in fuel element manufacturing procedures and inspection equipment will be exploited to reduce hot spot and hot streak factors sufficiently to permit the power upgrade without an increase in primary coolant pressure. Fresh fuel elements already fabricated for future use are being evaluated individually for power upgrade potential based on their measured coolant channel dimensions.
Date: March 1, 1997
Creator: Rothrock, R.B.; Hale, R.E. & Cheverton, R.D.
Partner: UNT Libraries Government Documents Department

Enhanced HFIR overpower margin through improvements in fuel plate homogeneity inspection

Description: Fuel homogeneity inspection techniques used on the HFIR fuel plates have recently been improved through conversion of the X-ray inspection device to acquire, store, and process data digitally. This paper reports some early results from using the improved equipment and describes future plans for obtaining enhanced fuel thermal performance by exploiting this improved inspection capability.
Date: September 1, 1995
Creator: Rothrock, R.B.; Hale, R.E.; Knight, R.W. & Cheverton, R.D.
Partner: UNT Libraries Government Documents Department

Status of High Flux Isotope Reactor (HFIR) post-restart safety analysis and documentation upgrades

Description: The High Flux Isotope Reactor (HFIR), an experimental reactor located at the Oak Ridge National Laboratory (ORNL) and operated for the US Department of Energy by Martin Marietta Energy Systems, was shut down in November, 1986 after the discovery of unexpected neutron embrittlement of the reactor vessel. The reactor was restarted in April, 1989, following an extensive review by DOE and ORNL of the HFIR design, safety, operation, maintenance and management, and the implementation of several upgrades to HFIR safety-related hardware, analyses, documents and procedures. This included establishing new operating conditions to provide added margin against pressure vessel failure, as well as the addition, or upgrading, of specific safety-related hardware. This paper summarizes the status of some of the follow-on (post-restart) activities which are currently in progress, and which will result in a comprehensive set of safety analyses and documentation for the HFIR, comparable with current practice in commercial nuclear power plants. 8 refs.
Date: January 1, 1990
Creator: Cook, D.H.; Radcliff, T.D.; Rothrock, R.B. & Schreiber, R.E.
Partner: UNT Libraries Government Documents Department

Loss-of-flow transient characterization in carbide-fueled LMFBRs

Description: One of the benefits derived from the use of carbide fuel in advanced Liquid Metal Fast Breeder Reactors (LMFBRs) is a decreased vulnerability to certain accidents. This can be achieved through the combination of advanced fuel performance with the enhanced reactivity feedback effects and passive shutdown cooling systems characteristic of the current 'inherently safe' plant concepts. The calculated core response to an unprotected loss of flow (ULOF) accident has frequently been used as a benchmark test of these designs, and the advantages of a high-conductivity fuel in relation to this type of transient have been noted in previous analyses. To evaluate this benefit in carbide-fueled LMFBRs incorporating representative current plant design features, limited calculations have been made of a ULOF transient in a small ('modular') carbide-fueled LMFBR.
Date: January 1, 1985
Creator: Rothrock, R.B.; Morgan, M.M.; Baars, R.E.; Elson, J.S. & Wray, M.L.
Partner: UNT Libraries Government Documents Department

FFTF initial fuel loading, preanalyses, and comparison with preliminary results

Description: Disadvantages of conventional loading from the center out were circumvented by loading one trisector at a time, and connecting the control rod drivelines in each sector after it was loaded so that the rods could be operated during the loading of subsequent trisectors. This sequence was interrupted once during the loading of the final sector, to achieve initial criticality at an approximately minimum critical loading and to measure absolute subcriticality by the rod drop technique. An in-core detector was preferable to the standard FTR ex-core detectors for monitoring the initial fuel loading. Consequently, special fission chambers were installed in an instrument thimble near the core center to monitor the initial fuel loading.
Date: February 1, 1980
Creator: Rothrock, R.B.; Daughtry, J.W.; Zimmerman, B.D.; Petrowicz, N.E.; Bennett, R.A. & Ombrellaro, P.A.
Partner: UNT Libraries Government Documents Department

Coincidence/Multiplicity Photofission Measurements

Description: An series of experiments using the Idaho National Laboratory (INL) photonuclear inspection system and a Los Alamos National Laboratory (LANL)-supplied, list-mode data acquisition method have shown enhanced performance utilizing pulsed photofission-induced, neutron coincidence counting between pulses of an up-to-10-MeV electron accelerator for nuclear material detection and identification. The enhanced inspection methodology has applicability to homeland security, treaty-related support, and weapon dismantlement applications. For the latter, this technology can directly support of Department of Energy/NA241 programmatic mission objectives relative to future Rocky Ridge-type testing campaigns for active inspection systems.
Date: September 1, 2009
Creator: Jones, J.L.; Swinhoe, M.T.; Tobin, S.J.; Geist, W. H.; Norman, D.R.; Rothrock, R.B. et al.
Partner: UNT Libraries Government Documents Department

Achieving increased spent fuel storage capacity at the High Flux Isotope Reactor (HFIR)

Description: The HFIR facility was originally designed to store approximately 25 spent cores, sufficient to allow for operational contingencies and for cooling prior to off-site shipment for reprocessing. The original capacity has now been increased to 60 positions, of which 53 are currently filled (September 1994). Additional spent cores are produced at a rate of about 10 or 11 per year. Continued HFIR operation, therefore, depends on a significant near-term expansion of the pool storage capacity, as well as on a future capability of reprocessing or other storage alternatives once the practical capacity of the pool is reached. To store the much larger inventory of spent fuel that may remain on-site under various future scenarios, the pool capacity is being increased in a phased manner through installation of a new multi-tier spent fuel rack design for higher density storage. A total of 143 positions was used for this paper as the maximum practical pool capacity without impacting operations; however, greater ultimate capacities were addressed in the supporting analyses and approval documents. This paper addresses issues related to the pool storage expansion including (1) seismic effects on the three-tier storage arrays, (2) thermal performance of the new arrays, (3) spent fuel cladding corrosion concerns related to the longer period of pool storage, and (4) impacts of increased spent fuel inventory on the pool water quality, water treatment systems, and LLLW volume.
Date: December 31, 1994
Creator: Cook, D.H.; Chang, S.J.; Dabs, R.D.; Freels, J.D.; Morgan, K.A.; Rothrock, R.B. et al.
Partner: UNT Libraries Government Documents Department

The Argonne beamline-B telescope control system: A study of adaptability

Description: A beam-expanding telescope to study high-precision H/sup -/ particle optics and beam sensing was designed by the Accelerator Technology Division at Los Alamos National Laboratory and will be installed on beamline-B at Argonne National Laboratory. The control system for this telescope was developed in a relatively short period of time using experience gained from building the Proton Storage Ring (PSR) control system. The designers modified hardware and software to take advantage of new technology as well as to meet the requirements of the new system. This paper discusses lessons learned in the process of adapting hardware and software from an existing control system to one with rather different requirements.
Date: January 1, 1987
Creator: Fuka, M.A.; Clout, P.N.; Conley, A.P.; Hill, J.O.; Rothrock, R.B.; Trease, L.L. et al.
Partner: UNT Libraries Government Documents Department

Initial physics measurements on FFTF

Description: Initial criticality of the Fast Flux Test Facility (FFTF) was achieved on February 9, 1980 at 3:45 p.m. During the period November 27, 1979 to March 8, 1980, fuel was loaded into the FFTF core, initial criticality was achieved, and several subcritical physics measurements were performed. The data obtained from initial FFTF nuclear operation are presented. Specifically, the absolute and relative neutron count rates were predicted for the bulk of the seventy-three fuel loadings of FFTF. Agreement between predicted and observed values is illustrated. Severe variations of fission chamber detection efficiency in the reactor shield is contrasted with that near the core center. Control rod worths, measured by the rod drop inverse kinetics method, are compared with predictions based upon Engineering Mockup Critical (EMC) evaluations. Control rod reactivity worth curves measured by rod run-in inverse kinetics are given.
Date: January 1, 1980
Creator: Bennett, R.A.; Daughtry, J.W.; Harris, R.A.; Jones, D.H.; King, T.L.; Midgett, J.C. et al.
Partner: UNT Libraries Government Documents Department

Enhanced Photofission-based, Coincidence/Multiplicity Inspection Measurements

Description: An enhanced active interrogation system has been developed that integrates a transportable Idaho National Laboratory (INL) photonuclear inspection system, using a pulsed bremsstrahlung source and a reconfigurable neutron detection system, with a Los Alamos National Laboratory (LANL) list-mode data acquisition system. A series of active interrogation experiments have shown enhanced nuclear material detection and identification utilizing pulsed photofission-induced, neutron coincidence/multiplicity counting between pulses of an up-to-10-MeV electron accelerator. This paper describes the integrated inspection system and presents some key shielded and unshielded nuclear material inspection results. The enhanced inspection methodology has applicability to homeland security and possible nuclear weapon dismantlement treaties.
Date: July 1, 2010
Creator: Jones, J.L.; Norman, D.R.; Haskell, K.J.; Swinhoe, M.T.; Tobin, S.J.; Geist, W.H. et al.
Partner: UNT Libraries Government Documents Department

The accelerator automation application toolkit workshop presentations

Description: Over the past 18 months on the GTA project at Los Alamos, we have been developing tools for building control systems for accelerators. The first tool developed has already demonstrated greatly reduced requirements for conventional computer programming in applying control systems to an accelerator. Even in the early stages, this work has received considerable attention and the system is currently being investigated or used at several other institutes. Further tools are either in the conceptual design, design, or implementation phase. Over the same period, a group at CERN has been developing the ideas and design for a generic software kit for the application of a control system to accelerators. The CERN software kit also addresses the technical management and documentation aspects of control systems. The purpose of the AT Division effort and the CERN kit is to greatly simplify the implementation and lifetime maintenance of an accelerator control system. Experience has shown that accelerator control systems are also applicable to other experimental physics machines. The purpose of the workshop was to explore these ideas and developments as well as other relevant developments in the field, to verify the viability of the concepts, and to develop further the written specifications for some of the components of such a toolkit. We had draft specifications prepared prior to the workshop. 21 figs.
Date: January 1, 1988
Creator: Howell, J.A.; Bjorklund, E.A.; Clout, P.N.; Dalesio, L.R.; Kozubal, A.J.; Mottershead, C.T. et al.
Partner: UNT Libraries Government Documents Department

Nuclear startup, testing and core management of the FTR

Description: The Fast Test Reactor (FTR) is a sodium-cooled, mixed-oxide-fueled, 400 MW(Th) fast reactor designed for irradiation testing of FB fuels and materials. The reactor is located near Richland, Washington, and is operated by the Westinghouse Hanford Company for the US Department of Energy. The FTR is presently undergoing nonnuclear startup tests, in preparation for the initial fuel loading. The reactor is provided with special irradiation facilities to enhance its experimental capabilities.
Date: August 1, 1979
Creator: Bennett, R. A.; Daughtry, J. V.; Harris, R. A.; Jones, D. H.; Nelson, J. W.; Rawlins, J. A. et al.
Partner: UNT Libraries Government Documents Department