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PNNL Review of Proposed Relevant Radionuclide List

Description: A list of fission products and activation products has been proposed for possible adoption as an official table of relevant isotopes for CTBT use. It is our understanding that the purpose of this list is to discriminate Level 4 spectra from Level 5 spectra in the decision logic diagram. The current understanding is that a single short-lived, relevant isotope that is atypical for a station would cause a spectrum to be marked as Level 4. A second relevant isotope would cause a spectrum to be marked as Level 5, which would perhaps require a sample to undergo additional laboratory conflation measurements. The list consists of a very comprehensive set of fission products and activation products. We have examined the list for accuracy and have also flagged potential problems with members of the list. in our opinion, several of these isotopes have serious problems and many have no practical chance of ever being the first or second detected isotopes. We are not arguing whether or not these isotopes might be seen in a large atmospheric test. On the other hand, there may be no harm associated with having a long list. The issue of activation products is different. Some activation products are indicative of the soil or rock composition in the vicinity of an explosion. Others may only be dependent on materials in the weapon or in the support structures. We don't think that a great deal of analysis of these isotopes by the CTBTO should be encouraged. In any case, if particulate activation products are in the atmosphere, fission products should be even more prevalent, thus removing the need for an activation list component.
Date: May 10, 1999
Creator: Miley, HS & Arthur, RJ
Partner: UNT Libraries Government Documents Department

Sequential charged-particle and neutron activation of Flibe in the HYLIFE-II inertial fusion energy power plant design

Description: Most radionuclide generation/depletion codes consider only neutron reactions and assume that charged particles, which may be generated in these reactions, deposit their energy locally without undergoing further nuclear interactions. Neglect of sequential charged-particle (x,n) reactions can lead to large underestimation in the inventories of radionuclides. PCROSS code was adopted for use with the ACAB activation code to enable calculation of the effects of (x,n) reactions upon radionuclide inventories and inventory-related indices. Activation calculations were made for Flibe (2LiF + BeF{sub 2}) coolant in the HYLIFE-II inertial fusion energy (IFE) power plant design. For pure Flibe coolant, it was found that (x,n) reactions dominate the residual contact dose rate at times of interest for maintenance and decommissioning. For impure Flibe, however, radionuclides produced directly in neutron reaction dominate the contact dose rate and (x,n) reactions do not make a significant contribution. Results demonstrate potential importance of (x,n) reactions and that the relative importance of (x,n) reactions varies strongly with the composition of the material considered. Future activation calculations should consider (x,n) reactions until a method for pre-determining their importance is established.
Date: June 14, 1996
Creator: Latkowski, J.F.; Tobin, M.T.; Vujic, J.L. & Sanz, J.
Partner: UNT Libraries Government Documents Department

Radionuclide mass inventory, activity, decay heat, and dose rate parametric data for TRIGA spent nuclear fuels

Description: Parametric burnup calculations are performed to estimate radionuclide isotopic mass and activity concentrations for four different Training, Research, and Isotope General Atomics (TRIGA) nuclear reactor fuel element types: (1) Aluminum-clad standard, (2) Stainless Steel-clad standard, (3) High-enrichment Fuel Life Improvement Program (FLIP), and (4) Low-enrichment Fuel Life Improvement Program (FLIP-LEU-1). Parametric activity data are tabulated for 145 important radionuclides that can be used to generate gamma-ray emission source terms or provide mass quantity estimates as a function of decay time. Fuel element decay heats and dose rates are also presented parametrically as a function of burnup and decay time. Dose rates are given at the fuel element midplane for contact, 3.0-feet, and 3.0-meter detector locations in air. The data herein are estimates based on specially derived Beginning-of-Life (BOL) neutron cross sections using geometrically-explicit TRIGA reactor core models. The calculated parametric data should represent good estimates relative to actual values, although no experimental data were available for direct comparison and validation. However, because the cross sections were not updated as a function of burnup, the actinide concentrations may deviate from the actual values at the higher burnups.
Date: March 1, 1997
Creator: Sterbentz, J.W.
Partner: UNT Libraries Government Documents Department

Production of radionuclides and their migration in groundwater: a Fermilab case history model

Description: Particle accelerators that are buried underground like those at Fermilab create a condition where soil can be activated. Naturally percolating groundwater becomes contaminated by leaching out some of the radioactivity as it migrates through the soil to the underlying aquifer. The Fermilab Concentration Model was formulated to account for and combine the fundamental processes of production, leaching, and migration. Its general features are described, then site-specific data from one of the target stations are used to make calculations and compare them to regulatory limits and DOE guidelines.
Date: August 1, 1997
Creator: Malensek, A.J.
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

Activation of the liquid helium contamination during its passage in the Collider ring

Description: Radioactivation of possible contamination of the liquid helium trapped in the arcs of the Collider ring of the Superconducting Super Collider and transported by the liquid helium is estimated. This estimation is used to calculate the dose rate on the filter of the refrigerator plant located at the top of the shaft.
Date: January 1, 1994
Creator: Lopez, G.
Partner: UNT Libraries Government Documents Department

Groundwater activation calculations for E872

Description: The E872 beam dump geometry has been modeled in CASIM and calculations have been done to determine the annual limits for protons n target. Results are presented using both the single resident well model (SRWM) and the newly-approved concentration model (CM). The conclusion is that the target/dump design is adequate for the maximum number of protons on target requested by the experiment, which is >1 {times} 10{sup 18} protons per year at 800 GeV.
Date: August 1, 1995
Creator: Freeman, W.S. & Collaboration, E872
Partner: UNT Libraries Government Documents Department

Halo and space charge issues in the SNS Ring

Description: The latest designs for high-intensity proton rings require minimizing beam-induced radioactivation of the vacuum chamber. Although the tune depression in the ring is much smaller than in high-intensity linacs, space-charge contributions to halo formation and, hence, beam loss may be significant. This paper reviews our current understanding of halo formation issues for the Spallation Neutron Source (SNS) accumulator ring.
Date: June 30, 2000
Creator: Fedotov, A.V.; Abell, D.T.; Beebe-Wang, J.; Lee, Y.Y.; Malitsky, N.; Wei, J. et al.
Partner: UNT Libraries Government Documents Department

Energy deposition issues at 8 GeV H- beam collimation and injection to the Fermilab Main Injector

Description: The energy deposition and radiation issues at 8 GeV h{sup -} beam collimation in the beam transfer line and at stripping injection to the Fermilab Main Injector (MI) are analyzed. Detailed calculations with the STRUCT [1] and MARS15 [2] codes are performed on heating of collimators and stripping foils, as well as on accelerator elements radioactivation at normal operation. Extraction of the unstripped part of the beam to the external beam dump and loss of the excited-state H{sup 0} atoms in MI are also studied.
Date: May 1, 2005
Creator: Drozhdin, A. I.; Kostin, M. A.; Mokhov, N. V. & /Fermilab
Partner: UNT Libraries Government Documents Department

Topics in radiation at accelerators: Radiation physics for personnel and environmental protection

Description: In the first chapter, terminology, physical and radiological quantities, and units of measurement used to describe the properties of accelerator radiation fields are reviewed. The general considerations of primary radiation fields pertinent to accelerators are discussed. The primary radiation fields produced by electron beams are described qualitatively and quantitatively. In the same manner the primary radiation fields produced by proton and ion beams are described. Subsequent chapters describe: shielding of electrons and photons at accelerators; shielding of proton and ion accelerators; low energy prompt radiation phenomena; induced radioactivity at accelerators; topics in radiation protection instrumentation at accelerators; and accelerator radiation protection program elements.
Date: October 1, 1996
Creator: Cossairt, J.D.
Partner: UNT Libraries Government Documents Department

H.B. Robinson-2 pressure vessel benchmark

Description: The H. B. Robinson Unit 2 Pressure Vessel Benchmark (HBR-2 benchmark) is described and analyzed in this report. Analysis of the HBR-2 benchmark can be used as partial fulfillment of the requirements for the qualification of the methodology for calculating neutron fluence in pressure vessels, as required by the U.S. Nuclear Regulatory Commission Regulatory Guide DG-1053, Calculational and Dosimetry Methods for Determining Pressure Vessel Neutron Fluence. Section 1 of this report describes the HBR-2 benchmark and provides all the dimensions, material compositions, and neutron source data necessary for the analysis. The measured quantities, to be compared with the calculated values, are the specific activities at the end of fuel cycle 9. The characteristic feature of the HBR-2 benchmark is that it provides measurements on both sides of the pressure vessel: in the surveillance capsule attached to the thermal shield and in the reactor cavity. In section 2, the analysis of the HBR-2 benchmark is described. Calculations with the computer code DORT, based on the discrete-ordinates method, were performed with three multigroup libraries based on ENDF/B-VI: BUGLE-93, SAILOR-95 and BUGLE-96. The average ratio of the calculated-to-measured specific activities (C/M) for the six dosimeters in the surveillance capsule was 0.90 {+-} 0.04 for all three libraries. The average C/Ms for the cavity dosimeters (without neptunium dosimeter) were 0.89 {+-} 0.10, 0.91 {+-} 0.10, and 0.90 {+-} 0.09 for the BUGLE-93, SAILOR-95 and BUGLE-96 libraries, respectively. It is expected that the agreement of the calculations with the measurements, similar to the agreement obtained in this research, should typically be observed when the discrete-ordinates method and ENDF/B-VI libraries are used for the HBR-2 benchmark analysis.
Date: February 1, 1998
Creator: Remec, I. & Kam, F.B.K.
Partner: UNT Libraries Government Documents Department

The impact of pulsed irradiation upon neutron activation calculations for inertial and magnetic fusion energy power plants

Description: Inertial fusion energy (IFE) and magnetic fusion energy (MFE) power plants will probably operate in a pulsed mode. The two different schemes, however, will have quite different time periods. Typical repetition rates for IFE power plants will be 1-5 Hz. MFE power plants will ramp up in current for about 1 hour, shut down for several minutes, and repeat the process. Traditionally, activation calculations for IFE and MFE power plants have assumed continuous operation and used either the ``steady state`` (SS) or ``equivalent steady state`` (ESS) approximations. It has been suggested recently that the SS and ESS methods may not yield accurate results for all radionuclides of interest. The present work expands that of Sisolak, et al. by applying their formulae to conditions which might be experienced in typical IFE and MFE power plants. In addition, complicated, multi-step reaction/decay chains are analyzed using an upgraded version of the ACAB radionuclide generation/depletion code. Our results indicate that the SS method is suitable for application to MFE power plant conditions. We also find that the ESS method generates acceptable results for radionuclides with half-lives more than a factor of three greater than the time between pulses. For components that are subject to 0.05 Hz (or more frequent) irradiation (such as coolant), use of the ESS method is recommended. For components or materials that are subject to less frequent irradiation (such as high-Z target materials), pulsed irradiation calculations should be used.
Date: June 26, 1996
Creator: Latkowski, J.F.; Sanz, J. & Vujic, J.L.
Partner: UNT Libraries Government Documents Department

Groundwater protection for the NuMI project

Description: The physics requirements for the long base line neutrino oscillation experiment MINOS dictate that the NuMI beamline be located in the aquifer at Fermilab. A methodology is described for calculating the level of radioactivation of groundwater caused by operation of this beamline. A conceptual shielding design for the 750 meter long decay pipe is investigated which would reduce radioactivation of the groundwater to below government standards. More economical shielding designs to meet these requirements are being explored. Also, information on local geology, hydrogeology, government standards, and a glossary have been included.
Date: October 1, 1997
Creator: Wehmann, A.; Smart, W.; Menary, S.; Hylen, J. & Childress, S.
Partner: UNT Libraries Government Documents Department

Summary report for ITER Task -- D4: Activation calculations for the stainless steel ITER design

Description: Detailed activation analysis for ITER has been performed as a part of ITER Task D4. The calculations have been performed for the shielding blanket (SS/water) and for the breeding blanket (LiN) options. The activation code RACC-P, which has been modified under IFER Task-D-10 for pulsed operation, has been used in this analysis. The spatial distributions of the radioactive inventory, decay heat, biological hazard potential, and the contact dose were calculated for the two designs for different operation modes and targeted fluences. A one-dimensional toroidal geometrical model has been utilized to determine the neutron fluxes in the two designs. The results are normalized for an inboard and outboard neutron wall loadings of 0.91 and 1.2 MW/M{sup 2}, respectively. The point-wise distributions of the decay gamma sources have been calculated everywhere in the reactor at several times after the shutdown of the two designs and are then used in the transport code ONEDANT to calculate the biological dose everywhere in the reactor. The point-wise distributions of all the responses have also been calculated. These calculations have been performed for neutron fluences of 3.0 MWa/M{sup 2}, which corresponds to the target fluence of ITER, and 0.1 MWa/M{sup 2}, which is anticipated to correspond to the beginning of an extended maintenance period.
Date: February 1, 1995
Creator: Attaya, H.
Partner: UNT Libraries Government Documents Department

Synchronization of the Fermilab Booster and Main Injector for multiple batch injection

Description: To date, the 120 GeV Fermilab Main Injector accelerator has accelerated a single batch of protons from the 8 GeV rapid-cycling Booster synchrotron for production of antiprotons for Run II. In the future, the Main Injector must accelerate 6 or more Booster batches simultaneously; the first will be extracted to the antiproton source, while the remaining are extracted for the NuMI/MINOS (Neutrinos at the Main Injector/Main Injector Neutrino Oscillation Search) neutrino experiment. Performing this multi-batch operation while avoiding unacceptable radioactivation of the beamlines requires a previously unnecessary synchronization between the accelerators. We describe a mechanism and present results of advancing or retarding the longitudinal progress of the Booster beam by active feedback radial manipulation of the beam during the acceleration period.
Date: July 9, 2004
Creator: al., Robert Zwaska et
Partner: UNT Libraries Government Documents Department

Code development incorporating environmental, safety and economic aspects of fusion reactors; Annual progress report

Description: This document is a proposal to continue the authors work on the Environmental, Safety and Economic (ESE) aspects of fusion reactors under DOE contract DE-FR03-89ER52514. The grant objectives continue those from the previous grant: (1) completion of first-generation Environmental, Safety and Economic (ESE) computer modules suitable as integral components of tokamak systems codes. (2) continuation of work on special topics, in support of the above and in response to OFE requests. The proposal also highlights progress on the contract in the twelve months since April, 1992. This has included work with the ARIES and ITER design teams, work on tritium management, studies on materials activation, and calculation of radioactive inventories in fusion reactors.
Date: December 31, 1993
Creator: Fowler, T.K.; Greenspan, E. & Holdren, J.P.
Partner: UNT Libraries Government Documents Department

Status of the ENDF/B special applications files

Description: The newly formed SAFE Subcommittee of the Cross Section Evaluation Working Group is charged with the responsibility for providing, reviewing, and testing several ENDF/B special purpose evaluated files. This responsibility currently encompasses dosimetry, activation, hydrogen and helium production, and radioactive decay data required by a variety of users. New formats have been approved by CSEWG for the inclusion of the activation and hydrogen and helium production cross-section libraries. The decay data will be in the same format as that already employed by the Fission Product and Actinide Subcommittee of CSEWG. While an extensive dosimetry file was available on the ENDF/B-IV library for fast reactor applications, other data are needed to extend the range of applications, especially to higher incident neutron energies. This Subcommittee has long-range plans to provide evaluated neutron interaction data that can be recommended for use in many specialized applications. 1 figure, 3 tables
Date: January 1, 1977
Creator: Stewart, L.
Partner: UNT Libraries Government Documents Department

Activated Corrosion Product Analysis. Analytical Approach.

Description: The presence of activated corrosion products (ACPs) in a water cooling system is a key factor in the licensing of ITER and affects nuclear classification, which governs design and operation. The objective of this study is to develop a method to accurately estimate radionuclide concentrations during ITER operation in support of nuclear classification. A brief overview of the PACTITER numerical code, which is currently used for ACP estimation, is presented. An alternative analytical approach for calculation of ACPs, which can also be used for validation of existing numerical codes, including PACTITER, has been proposed. A continuity equation describing the kinetics of accumulation of radioactive isotopes in a water cooling system in the form of a closed ring has been formulated, taking into account the following processes: production of radioactive elements and their decay, filtration, and ACP accumulation in filter system. Additional work is needed to more accurately assess the ACP inventory in the cooling water system, including more accurate simulation of the Tokamak cooling water system (TCWS) operating cycle and consideration of material corrosion, release, and deposition rates.
Date: January 1, 2010
Creator: Golubov, Stanislav I.; Busby, Jeremy T. & Stoller, Roger E.
Partner: UNT Libraries Government Documents Department

Overview of superconducting RF technology and its application to high-current linacs

Description: Superconducting linacs may be a viable option for high-current applications such as copious neutron production like that needed for transmutation of radioactive waste. These linacs must run reliably for many years and allow easy routine maintenance. superconducting cavities operate efficiently with high cw gradients, properties which help to reduce operating and capital costs. However, cost effectiveness is not the sole consideration in these applications. For example, beam impingement must be essentially eliminated to prevent unsafe radioactivation of the accelerating structures, and thus large apertures are needed through which to pass the beam. Because of their high efficiency, superconducting cavities can be designed with very large bore apertures, thereby reducing the effect of beam impingement.
Date: August 1, 1994
Creator: Delayen, J. R. & Bohn, C. L.
Partner: UNT Libraries Government Documents Department

Report of the task force on radioactivation

Description: Estimates have been made of the residual radioactivation of the components of the SSC accelerator and detector complex. Such activation is caused by the loss of a small fraction of the proton beams being transported in the SSC accelerator system, by deliberate removal (dumping) of the beams and by particles created in the proton-proton collisions in the SSC storage rings. Existing methodology that has been successfully used to determine activation levels at other accelerator facilities has also been used to estimate the activation of SSC components in those cases where calculational methods may be applied. In addition, we have used measurements from existing accelerators, primarily the Fermilab and CERN accelerators, to provide the means to estimate activation for those cases in which calculational methods, such as Monte Carlo shower codes, are difficult to apply. We have also used these measurements to check the calculations from the shower codes where possible. We have estimated activation levels and dose rates, where possible, for the following components of the SSC: The abort dumps for both the storage rings and the elements of the injector system; beam Collimators and scrapers; magnets and other apparatus in the region of injection/extraction from one accelerator to another, target stations used to create test beams from the high energy booster; superconducting magnets in the high energy booster and the storage rings; and representative detector elements. We also briefly discuss aspects of handling or dismantling the components most significantly activated and the relevance to decommissioning of the SSC complex. A short description of the decommissioning of the Intersecting Storage Rings at CERN, the only pp collider that has been decommissioned, is included in this report.
Date: October 1, 1987
Partner: UNT Libraries Government Documents Department

HETC96/MORSE calculations of activations in KEK beam stop and room by 500-MeV protons and comparisons with experiments

Description: The 1996 version of HETC has a pre-equilibrium reaction model to bridge the gap between the existing intranuclear-cascade and evaporation models. This code was used to calculate proton-induced activations, to calculate neutron fluxes for neutron energies above 19.6 MeV, and to write the neutron source for lower energies to be transported further by MORSE. For MORSE, the HILO cross section library was used for neutron transport for all detectors. Additionally for the {sup 197}Au(n, {gamma}) detector, the BUGLE96 library was used to study the effects of the low-lying {sup 57}Fe inelastic levels and the resonance self-shielding in iron. Neutron fluxes were obtained from the track-length estimator for detectors inside the beam stop and from the boundary-crossing estimator for detectors attached to the surfaces of the concrete walls. Activation cross sections given in JAERI-Data/Code are combined with the calculated neutron fluxes to get the saturated activities induced by neutrons. C/E values are too low (0.5) for Fe(N, {chi}){sup 54}Mn, close to unity for Cu(n, {chi}){sup 58}Co, and too high (6.0) for {sup 197}Au (n, {gamma}){sup 198}Au. It is difficult to interpret the disagreements because most of the activation cross sections are also calculated and their uncertainties are not known. However, the calculated results are in good agreement with those calculated by others using different codes. Calculated results for four of the ten activations reported here have not been done previously, and among the four, {sup 197}Au(n, {gamma}) is the most bothersome because its cross section is the most well known while the calculated activations for most detector locations are in largest disagreement with experiments.
Date: May 1, 1997
Creator: Fu, C.Y. & Gabriel, T.A.
Partner: UNT Libraries Government Documents Department

Preliminary radiation transport analysis for the proposed National Spallation Neutron Source (NSNS)

Description: The use of neutrons in science and industry has increased continuously during the past 50 years with applications now widely used in physics, chemistry, biology, engineering, and medicine. Within this history, the relative merits of using pulsed accelerator spallation sources versus reactors for neutron sources as the preferred option for the future. To address this future need, the Department of Energy (DOE) has initiated a pre-conceptual design study for the National Spallation Neutron Source (NSNS) and given preliminary approval for the proposed facility to be built at Oak Ridge National Laboratory (ORNL). The DOE directive is to design and build a short pulse spallation source in the 1 MS power range with sufficient design flexibility that it can be upgraded and operated at a significantly higher power at a later stage. The pre-conceptualized design of the NSNS initially consists of an accelerator system capable of delivering a 1 to 2 GeV proton beam with 1 MW of beam power in an approximate 0.5 microsecond pulse at a 60 Hz frequency onto a single target station. The NSNS will be upgraded in stages to a 5 MW facility with two target stations (a high power station operating at 60 Hz and a low power station operating at 10 Hz). Each target station will contain four moderators (combinations of cryogenic and ambient temperature) and 18 beam liens for a total of 36 experiment stations. This paper summarizes the radiation transport analysis strategies for the proposed NSNS facility.
Date: March 1997
Creator: Johnson, J. O. & Lillie, R. A.
Partner: UNT Libraries Government Documents Department