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Working Group

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ANS-5.1, Decay Heat Power in Light Water Reactors

Scope: This standard sets forth values for the decay heat power from fission products and 239U and 239Np following shutdown of light water reactors (LWRs) containing 235U, 238U, and plutonium. The decay heat power from fission products is presented in tables and equivalent analytical representations. Methods are described that account for the reactor operating history, for the effect of neutron capture in fission products, and for assessing the uncertainty in the resultant decay heat power. Decay heat power from other actinides and activation products in structural materials, and fission power from delayed neutron-induced fission, are not included in this standard and shall be evaluated by the user and appropriately included in any analysis of shutdown power.

ANS-19.1, Nuclear Data Sets for Reactor Design Calculations

Scope: This standard identifies and describes the specifications for developing, preparing, and documenting nuclear data sets to be used in reactor design calculations. The specifications include (a) criteria for acceptance of evaluated nuclear data sets, (b) criteria for processing evaluated data and preparation of processed continuous data and averaged data sets (c) identification of specific evaluated, processed continuous and averaged data sets that meet these criteria for specific reactor types.

ANS-19.3, Determination of Steady-State Neutron Reaction-Rate Distributions and Reactivity of Nuclear Power Reactors

Scope: This standard provides guidance for performing and validating the sequence of steady state calculations leading to prediction, in all types of nuclear reactors, of: (1) Reaction rate spatial distributions (2) Reactivity (3) Change of isotopic compositions with time. The standard provides: (1) Guidance for the selection of computational methods. (2) Criteria for verification of calculational methods used by reactor core analysts (3) Criteria for evaluation of accuracy and range of applicability of data and methods (4) Requirements for documentation of the preceding. The scope of the standard is shown schematically in Figure 1.

ANS-19.3.4, The Determination of Thermal Energy Deposition Rates in Nuclear Reactors

Scope: It is the purpose of this standard to provide criteria for: (1) Determination of the energy allocation among the principal particles and photons produced in fission, both prompt and delayed; (2) Adoption of appropriate treatment of heavy charged particle and electron slowing down in matter; (3) Determination of the spatial energy deposition rates resulting from the interactions of neutrons; (4) Calculation of the spatial energy deposition rates resulting from the various interactions of photons with matter; and (5) Presentation of the results of such computations, including verification of accuracy and specification of uncertainty. This standard addresses the energy generation and deposition rates for all types of nuclear reactors where the neutron reaction rate distribution and photon and beta emitter distributions are known. Its scope is limited to the reactor core, including blanket zones, control elements and core internals, pressure vessel, and the thermal and biological shielding.

ANS-19.4, A Guide for Acquisition and Documentation of Reference Power Reactor Physics Measurements for Nuclear Analysis Verification

Scope: This standard applies to measurements of reactor parameters in light water power reactors that are intended to serve as reference measurements to be used in evaluating reactor physics computational procedures. It includes: identification of the types of parameters of interest as reference measurements; a brief description of test conditions and experimental data required for such reference measurements; identification of problems and concerns which may affect the accuracy or interpretation of the data; and criteria to be used in documenting the results of reference measurements.

ANS-19.5, Requirements for Reference Reactor Physics Measurements

Scope: This standard provides criteria for the qualification of reference reactor physics measurements obtained from subcritical (including non-multiplying), critical, and other experiments for the purpose of verifying nuclear design and analysis methods. It also provides criteria for documentation of reference data and review of proposed reference reactor physics data to ensure compliance with this standard.

ANS-19.6.1, Reload Startup Physics Tests for Pressurized Water Reactors

Scope: This standard specifies the minimum acceptable startup reactor physics test program to determine if the operating characteristics of the core are consistent with the design predictions, which provides assurance that the core can be operated as designed.

ANS-19.8, Fission Product Yields for 235U, 238U, and 239P

Scope: This standard provides a reference set of fission yield data for thermal and fast neutron-induced fission of 233 U, 235U, 239Pu, and 241Pu; fast neutron-fission of 232Th, 238U, and 240PU; and spontaneous fission of 252CF. The data for these 12 fissioning systems are given as mass chain yields and their uncertainties and are presented in tabular form. Discussions are presented and references given concerning the application of the data. Concerns associated with the uncertainties in the mass chain yields are also discussed. A set of cumulative fission yields and uncertainties are included explicitly for a number of special purpose fission-product nuclides, particularly those important to dosimetry.

ANS-19.9, Delayed Neutron Parameters for Light Water Reactors

Scope: This standard provides energy-dependent delayed neutron yield and decay data for Light Water Reactor design and control. The standard addresses the identification and characterization of fission products leading to delayed neutron emission; the total delayed neutron yield as a function of energy for U-233, U-235, U-238 and Pu-239; and fractions associated with individual emitters, half-lives and spectra for the classical group representation of delayed neutron data

ANS-19.10, Methods for Determining Neutron Fluence in BWR and PWR Pressure Vessel and Reactor Internals

Scope: This standard provides criteria for performing and validating the sequence of calculations required for the prediction of the fast neutron fluence t in the reactor vessel. Applicable to PWR and BWR plants the standard addresses flux attenuation from the core through the vessel to the cavity and provides criteria for generating cross sections, spectra, transport and comparisons with in- and ex-vessel measurements, validation, uncertainties and flux extrapolation to the inside vessel surface.

ANS-19.11, Calculation and Measurement of the Moderator Temperature Coefficient of Reactivity for Water Moderated Power Reactors

Scope: This standard provides guidance and specifies criteria for determining the MTC in water moderated power reactors. Measurement of the isothermal temperature coefficient of reactivity (ITC) at hot zero power (HZP) conditions is covered in American National Standard Reload Startup Physics Tests for Pressurized Water Reactors, ANSI/ANS-19.6.1-1997. This standard therefore addresses the calculation of the ITC at HZP and the calculation and measurement of the MTC at power. At present, this standard addresses the calculation and measurement of the MTC only in PWRs, because that is the only type of power reactor currently sited in the United States for which measurement of the MTC is required.

ANS-19.12, Nuclear Data for Isotope Production Calculations for Medical and Other Applications

Scope: This standard establishes criteria for developing evaluated neutron cross section and branching ratio data for isotope production pathways for fast and thermal reactor systems, providing the data needed to calculate production of the desired medical and other isotopes and associated impurities.

Last updated July 22, 2014, 3:03pm CDT.

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