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Validation of neutron-transport calculations in benchmark facilities for improved damage-fluence predictions

Description: An accurate determination of damage fluence accumulated by reactor pressure vessels (RPV) as a function of time is essential in order to evaluate the vessel integrity for both pressurized thermal shock (PTS) transients and end-of-life considerations. The desired accuracy for neutron exposure parameters such as displacements per atom or fluence (E > 1 MeV) is of the order of 20 to 30%. However, these types of accuracies can only be obtained realistically by validation of nuclear data and calculational methods in benchmark facilities. The purposes of this paper are to review the needs and requirements for benchmark experiments, to discuss the status of current benchmark experiments, to summarize results and conclusions obtained so far, and to suggest areas where further benchmarking is needed.
Date: January 1, 1983
Creator: Williams, M.L.; Stallmann, F.W.; Maerker, R.E. & Kam, F.B.K.
Partner: UNT Libraries Government Documents Department

LSL-M1 and LSL-M2: two extensions of the LSL adjustment procedure for including multiple spectrum locations

Description: Most current adjustment procedures, including LSL, can adjust only one spectrum with dosimetry located at the point of the input spectrum. Many radiation experiments have dosimetry at more than one location, and fluence or damage exposure values are desired for locations other than those covered by dosimetry. Thus, the use of single-spectrum dosimetry to these experiments causes considerable loss of information and introduces large uncertainties. Two extensions of the LSL code to cover multiple-spectra adjustment are discussed. Each extension has different restrictions and covers a different range of applications.
Date: January 1, 1984
Creator: Stallmann, F. W.
Partner: UNT Libraries Government Documents Department

Radiation Environment in the Tunnel of a High-Energy Proton Accelerator at Energies Near 1 TeV

Description: Neutron energy spectra, fluence distributions and rates in the FNAL Tevatron tunnel are summarized. This work has application to radiation damage to electronics and research equipment at high energy accelerators, as well as to radiological protection. 7 refs., 4 figs.
Date: December 1987
Creator: McCaslin, J. B.; Sun, R. K. S.; Swanson, W. P.; Cossairt, J. D.; Elwyn, A. J.; Freeman, W. S. et al.
Partner: UNT Libraries Government Documents Department

Design assumptions and bases for small D-T-fueled Sperical Tokamak (ST) fusion core

Description: Recent progress in defining the assumptions and clarifying the bases for a small D-T-fueled ST fusion core are presented. The paper covers several issues in the physics of ST plasmas, the technology of neutral beam injection, the engineering design configuration, and the center leg material under intense neutron irradiation. This progress was driven by the exciting data from pioneering ST experiments, a heightened interest in proof-of-principle experiments at the MA level in plasma current, and the initiation of the first conceptual design study of the small ST fusion core. The needs recently identified for a restructured fusion energy sciences program have provided a timely impetus for examining the subject of this paper. Our results, though preliminary in nature, strengthen the case for the potential realism and attractiveness of the ST approach.
Date: December 31, 1996
Creator: Peng, Y.K.M.; Galambos, J.D. & Fogarty, P.J.
Partner: UNT Libraries Government Documents Department

High-flux source of fusion neutrons for material and component testing

Description: The inner part of a fusion reactor will have to operate at very high neutron loads. In steady-state reactors the minimum fluence before the scheduled replacement of the reactor core should be at least l0-15 Mw.yr/m<sup>2</sup>. A more frequent replacement of the core is hardly compatible with economic constraints. A most recent summary of the discussions of these issues is presented in Ref. [l]. If and when times come to build a commercial fusion reactor, the availability of information on the behavior of materials and components at such fluences will become mandatory for making a final decision. This makes it necessary an early development and construction of a neutron source for fusion material and component testing. In this paper, we present information on one very attractive concept of such a source: a source based on a so called Gas Dynamic Trap. This neutron source was proposed in the mid 1980s (Ref. [2]; see also a survey [3] with discussion of the early stage of the project). Since then, gradual accumulation of the relevant experimental information on a modest-scale experimental facility GDT at Novosibirsk, together with a continuing design activity, have made initial theoretical considerations much more credible. We believe that such a source can be built within 4 or 5 years. Of course, one should remember that there is a chance for developing steady-state reactors with a liquid (and therefore continuously renewable) first wall [4], which would also serve as a tritium breeder. In this case, the need in the neutron testing will become less pressing. However, it is not clear yet that the concept of the flowing wall will be compatible with all types of steady-state reactors. It seems therefore prudent to be prepared to the need of a quick construction of a neutron source. It should also be ...
Date: January 7, 1999
Creator: Baldwin, D. E.; Hooper, E. B.; Ryutov, D. D. & Thomassen, K. I.
Partner: UNT Libraries Government Documents Department

Neutron Exposure Parameters for the Dosimetry Capsule in the Heavy-Section Steel Irradiation Program Tenth Irradiation Series

Description: This report describes the computational methodology for the least-squares adjustment of the dosimetry data from the HSSI 10.OD dosimetry capsule with neutronics calculations. It presents exposure rates at each dosimetry location for the neutron fluence greater than 1.0 MeV, fluence greater than 0.1 MeV, and displacements per atom. Exposure parameter distributions are also described in terms of three- dimensional fitting functions. When fitting functions are used it is suggested that an uncertainty of 6% (1 o) should be associated with the exposure rate values. The specific activity of each dosimeter at the end of irradiation is listed in the Appendix.
Date: October 1, 1998
Creator: Baldwin, C.A.; Kam, F.B.K. & Remec, I.
Partner: UNT Libraries Government Documents Department