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Nonuniform Burnup and Poisoning Effects in a Reactor and Validity of Uniform Approximation

Description: Memorandum presenting the application of the nuclear-reactor simulator to an investigation of the validity of the customary assumption of uniform distributions of fuel burnup and fission-product poisoning in a reactor core. The two-group calculation results show the effects of the approximation on the reactivity, power distribution, and xenon-135 distribution for a specific power reactor in which the initial power density varied by a factor of approximately 4 over the core volume.
Date: March 9, 1953
Creator: Spooner, Robert B.
Partner: UNT Libraries Government Documents Department

The RBU Reactor-Burnup Code: Formulation and Operation Procedures

Description: Report discussing the computer program RBU, which calculates the neutron, reactivity, and isotopic history of a nuclear reactor in such a way as to facilitate the predictions of fuel costs and reactor performance. This report documents RBU's various calculations and operating procedures.
Date: July 1961
Creator: Triplett, J. R.; Merrill, E. T. & Burr, J. R.
Partner: UNT Libraries Government Documents Department

Experiment Safety Assurance Package for the 40- to 50-GWd/MT Burnup Phase of Mixed Oxide Fuel Irradiation in Small I-Hole Positions in the Advanced Test Reactor

Description: This experiment safety assurance package (ESAP) is a revision of the last MOX ESAP issued in February 2001(Khericha 2001). The purpose of this revision is to identify the changes in the loading pattern and to provide a basis to continue irradiation up to ~42 GWd/MT burnup (+ 2.5% as predicted by MCNP (Monte Carlo N-Particle) transport code before the preliminary postirradiation examination (PIE) results for 40 GWd/MT burnup are available. Note that the safety analysis performed for the last ESAP is still applicable and no additional analysis is required (Khericha 2001). In July 2001, it was decided to reconfigure the test assembly using the loading pattern for Phase IV, Part 3, at the end of Phase IV, Part 1, as the loading pattern for Phase IV, Parts 2 and 3. Three capsule assemblies will be irradiated until the highest burnup capsule assembly accumulates: ~50 GWd/MT burnup, based on the MCNP code predictions. The last ESAP suggests that at the end of Phase IV, Part 1, we remove the two highest burnup capsule assemblies (@ ~40 GWd/MT burnup) and send them to ORNL for PIE. Then, irradiate the test assembly using the loading pattern for Phase IV, Part 2, until the highest burnup capsule reaches ~40 GWd/MT burnup per MCNP-predicted values.
Date: June 1, 2002
Creator: Khericha, Soli T
Partner: UNT Libraries Government Documents Department

ATR PDQ and MCWO Fuel Burnup Analysis Codes Evaluation

Description: The Advanced Test Reactor (ATR) at the Idaho National Laboratory (INL) is being studied to determine the feasibility of converting it from the highly enriched Uranium (HEU) fuel that is currently uses to low enriched Uranium (LEU) fuel. In order to achieve this goal, it would be best to qualify some different computational methods than those that have been used at ATR for the past 40 years. This paper discusses two methods of calculating the burnup of ATR fuel elements. The existing method, that uses the PDQ code, is compared to a modern method that uses A General Monte Carlo N-Particle Transport Code (MCNP) combined with the Origen2.2 code. This modern method, MCNP with ORIGEN2.2 (MCWO), is found to give excellent agreement with the existing method (PDQ). Both of MCWO and PDQ are also in a very good agreement to the 235U burnup data generated by an analytical method.
Date: November 1, 2009
Creator: Chang, G.S.; Roth, P. A. & Lillo, M. A.
Partner: UNT Libraries Government Documents Department

MCWO - Linking MCNP And ORIGEN2 For Fuel Burnup Analysis

Description: The UNIX BASH (Bourne Again Shell) script MCWO has been developed at the Idaho National Engineering and Environment Laboratory (INEEL) to couple the Monte Carlo transport code MCNP with the depletion and buildup code ORIGEN2. MCWO is a fully automated tool that links the Monte Carlo transport code MCNP with the radioactive decay and burnup code ORIGEN2. MCWO can handle a large number of fuel burnup and material loading specifications, Advanced Test Reactor (ATR) powers, and irradiation time intervals. The program processes input from the user that specifies the system geometry, initial material compositions, feed/removal specifications, and other code-specific parameters. Calculated results from MCNP, ORIGEN2, and data process module calculations are then output successively as the code runs. The principal function of MCWO is to transfer one-group cross-section and flux values from MCNP to ORIGEN2, and then transfer the resulting material compositions (after irradiation and/or decay) from ORIGEN2 back to MCNP in a repeated, cyclic fashion. The basic requirement of the code is that the user have a working MCNP input file and other input parameters; all interaction with ORIGEN2 and other calculations are performed by UNIX BASH script MCWO. This paper presents the MCWO-calculated results of the RERTR-1 and -2 , and the Weapons-Grade Mixed Oxiide fuel (Wg-MOX) fuel experiments in ATR and compares the MCWO-calculated results with the measured data.
Date: April 1, 2005
Creator: Chang, Gray S
Partner: UNT Libraries Government Documents Department

The Challenges Associated with High Burnup and High Temperature for UO2 TRISO-Coated Particle Fuel

Description: The fuel service conditions for the DOE Next Generation Nuclear Plant (NGNP) will be challenging. All major fuel related design parameters (burnup, temperature, fast neutron fluence, power density, particle packing fraction) exceed the values that were qualified in the successful German UO2 TRISO-coated particle fuel development program in the 1980s. While TRISO-coated particle fuel has been irradiated at NGNP relevant levels for two or three of the design parameters, no data exist for TRISO-coated particle fuel for all five parameters simultaneously. Of particular concern are the high burnup and high temperatures expected in the NGNP. In this paper, where possible, we evaluate the challenges associated with high burnup and high temperature quantitatively by examining the performance of the fuel in terms of different known failure mechanisms. Potential design solutions to ameliorate the negative effects of high burnup and high temperature are also discussed.
Date: February 1, 2005
Creator: Petti, David & Maki, John
Partner: UNT Libraries Government Documents Department

Gross Gamma Dose Rate Measurements for TRIGA Spent Nuclear Fuel Burnup Validation

Description: Gross gamma-ray dose rates from six spent TRIGA fuel elements were measured and compared to calculated values as a means to validate the reported element burnups. A newly installed and functional gamma-ray detection subsystem of the In-Cell Examination System was used to perform the measurements and is described in some detail. The analytical methodology used to calculate the corresponding dose rates is presented along with the calculated values. Comparison of the measured and calculated dose rates for the TRIGA fuel elements indicates good agreement (less than a factor of 2 difference). The intent of the subsystem is to measure the gross gamma dose rate and correlate the measurement to a calculated dose rate based on the element s known burnup and other pertinent spent fuel information. Although validation of the TRIGA elements’ burnup is of primary concern in this paper, the measurement and calculational techniques can be used to either validate an element’s reported burnup or provide a burnup estimate for an element with an unknown burnup.
Date: April 1, 2001
Creator: Winston, Philip Lon & Sterbentz, James William
Partner: UNT Libraries Government Documents Department

Isotopic depletion with Monte Carlo

Description: This work considers a method to deplete isotopes during a time- dependent Monte Carlo simulation of an evolving system. The method is based on explicitly combining a conventional estimator for the scalar flux with the analytical solutions to the isotopic depletion equations. There are no auxiliary calculations; the method is an integral part of the Monte Carlo calculation. The method eliminates negative densities and reduces the variance in the estimates for the isotope densities, compared to existing methods. Moreover, existing methods are shown to be special cases of the general method described in this work, as they can be derived by combining a high variance estimator for the scalar flux with a low-order approximation to the analytical solution to the depletion equation.
Date: June 1, 1996
Creator: Martin, W.R. & Rathkopf, J.A.
Partner: UNT Libraries Government Documents Department

Value of burnup credit beyond actinides

Description: DOE has submitted a topical report to the NRC justifying burnup credit based only on actinide isotopes (U-234, U-235, U-236, U-238, Pu-238, Pu-239, Pu-240, Pu-241, Pu-242, and Am-241). When this topical report is approved, it will allow a great deal of the commercial spent nuclear fuel to be transported in significantly higher capacity casks. A cost savings estimate for shipping fuel in 32 assembly (burnup credit) casks as opposed to 24 assembly (non-burnup credit) casks was previously presented. Since that time, more detailed calculations have been performed using the methodology presented in the Actinide-Only Burnup Credit Topical Report. Loading curves for derated casks have been generated using actinide-only burnup credit and are presented in this paper. The estimates of cost savings due to burnup credit for shipping fuel utilizing 32, 30, 28, and 24 assembly casks where only the 24 assembly cask does not burnup credit have been created and are discussed. 4 refs., 2 figs.
Date: December 1, 1997
Creator: Lancaster, D.; Fuentes, E. & Kang, Chi
Partner: UNT Libraries Government Documents Department

HIGHLY SELF-SHIELDED BURNABLE POISONS

Description: A new and different type of burnable poison element which can be used essentially to match any decreasing reactivity curve in a reactor and still have a tolerable residue was studied. Specific application is made to Gd as the poison elements; however, the results would be similar for any other suitable high cross-section element such as Cd. (J.R.D.)
Date: March 1, 1963
Creator: Holl, R.J.
Partner: UNT Libraries Government Documents Department

METALLOGRAPHY OF IRRADIATED UO$sub 2$-CONTAINING FUEL ELEMENTS

Description: A description of hot laboratory metallography and techniques of operation are presented. These facilities and techniques provided a means of examining fuel elements that contain UO/sub 2/ after irradiation to high burnups. Some unusual irradiation characteristics of UO/sub 2/ were observed, and each effect is discussed. A complete explanation of the causes of such effects has not yet been obtained. (auth)
Date: January 15, 1958
Creator: Barney, W.K. & Wemple, B.D.
Partner: UNT Libraries Government Documents Department

REACTIVITY LIFETIME 5091.4-5806.1 EFPH. CORE I, SEED 1. Test Results T- 612118-B

Description: The Shippingport Atomic Power Station was operated for 715 EFPH from Ang. 11 to Oct. 7, 1959, in order to determine the performance characteristics reliability, stability, and lifetime variation of the core during rated power operation for an extended period of time. The plant was operated at successively lower power levels of 60, 43, and 17 Mwe to extend the Core I, Seed 1 lifetime. Logs and tables are included which present the events and all recorded data in this period. (D.L.C.)
Date: August 1, 1960
Partner: UNT Libraries Government Documents Department

Phenomena and Parameters Important to Burnup Credit

Description: Since the mid-1980s, a significant number of studies have been directed at understanding the phenomena and parameters important to implementation of burnup credit in out-of-reactor applications involving pressurized-water-reactor (PWR) spent fuel. The efforts directed at burnup credit involving boiling-water-reactor (BWR) spent fuel have been more limited. This paper reviews the knowledge and experience gained from work performed in the US and other countries in the study of burnup credit. Relevant physics and analysis phenomenon are identified, and an assessment of their importance to burnup credit implementation for transport and dry cask storage is given.
Date: January 10, 2001
Creator: Parks, C. V.
Partner: UNT Libraries Government Documents Department