DLC-0055 ZZ-RECOIL/B.

ZZ-RECOIL/B.

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FORMAT: GAM-II group structure

NUMBER OF GROUPS: 104 neutron and Recoil-energy groups

NUCLIDES: Elements Included in Charged-Particle Recoil Data Base: Al, W, Ti, Pb, V, Mg, Cr, Be, Mn, C, Fe, Au, Co, Si, Ni, B-10, Cu, B-11, Zr, N, Nb, Li-6, Mo, Li-7, Ta (Data for Ta-181,Ta-182), O,

ORIGIN: ENDF/B-IV cross-section data

WEIGHTING SPECTRUM:

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A heavy charged-particle recoil data base (primary knock-on atom (PKA) spectra) and an analysis program have been created to assist experimentalists in studying, evaluating, and correlating radiation-damage effects in different neutron environments. Since experimentally obtained controlled thermo-nuclear-reactor-type neutron spectra are not presently available, the data base can be extremely useful in relating currently obtainable radiation damage to that which is anticipated in future fusion devices. However, the usefulness of the data base is not restricted to just CTR needs. Most of the elements of interest to the radiation-damage community and all neutron reactions of any significance for these elements have been processed, using available ENDF/B-IV cross-section data, and are included in the data base. Calculated data such as primary recoil spectra, displacement rates, and gas-production rates, obtained with the data base, for different radiation environments are presented and compared with previous calculations. Primary neutrons with energies up to 20 MeV have been considered. The elements included in the data base are listed in Table I.

All neutron reactions of significance for these elements (i.e., elastic, inelastic, (n,2n), (n,3n), (n,p), (n,nα), (n,γ), etc.,) which have cross sections available from ENDF/B-IV have been  processed and placed in the data base.

TABLE I

Elements Included in Charged-Particle Recoil Data Base

The neutron group structure up to 14.91 MeV is the same as the GAM-II group structure. (1) The recoil group structure used is based on equal lethargy intervals from 20 eV to 10 MeV.

For elastic, inelastic, (n,2n), (n,3n), (n,np), and (n,nα) reactions, a modified version of the XLACS module from the AMPX code system (1) was used to calculate the heavy charged-particle recoil spectra. For elastic and inelastic resolved reactions, where angular distributions are usually available, the recoil spectra were obtained in the form of a neutron-group- (gn) to-recoil group (gR) transfer matrix.

For the remaining reactions given above, the recoil spectra were obtained by using a one-neutron emission model(2) and the secondary- neutron spectra (assumed to be applicable at all angles in the center-of-mass system) given in ENDF/B-IV.

For neutron absorption reactions, such as (n,p), (n,α), etc., the methods of Doran, (2) Jenkins, (3) and Parkin and Goland (4) were used.

NEA-DB executed test cases of the various processing codes distributed with the data library. The following CPU times were required:

• Data conversion program:        3 seconds

• Group boundary conversion:      1 second

• RECOIL:                         7 seconds.

The following processing programs are included with the data base:

1. A Group Boundary Conversion Program.

2. RECOIL: BCD to binary conversion program.

• N.M. Greene et al.: AMPX: A Modular Code System for Generating Coupled Multigroup Neutron-Gamma Libraries from ENDF/B, ORNL-TM-37-6, Oak Ridge National Laboratory (to be published).

• J.D. Jenkins: Nucl. Sci. Eng. 41, 155 (1970).

• D.G. Doran: Nucl. Sci. Eng. 49, 130 (1972).

• D.M. Parkin and A.N. Goland: A Computational Method for the Evaluation of Radiation Effects Producted by CTR-Related Neutron Spectra, Brookhaven National Laboratory Report (1974).

• J. Lindhard et al. : Mat. Fys. Medd. Dan. Vid. Selsk 33, 1 (1963).

• M.T. Robinson: Nuclear Fusion Reactors, Proc. British Nuclear Energy Society Conference, Culham Laboratory, September 1969, p. 364.

• D.M. Parkin and A.N. Goland: Analysis of Radiation Damage in Fusion Simulation Neutron Spectra,presented at the International Conference on Radiation Effects and Tritium Technology for Fusion Reactors, October 1-3, 1975, Gatlinburg, Tennessee (to be published in the proceedings).

• R.T. Santoro:  Neutronics Calculations for the Tokamak Experimental Power Reactor Reference Design, ORNL-TM-5033, Oak Ridge National Laboratory (1975).

• G.L. Kulcinski, D.G. Doran, and M.A. Abdou: Comparison of Displacement and Gas Production Rates in Current Fission and Future Fusion Reactors, UWFDM-15, University of Wisconsin (1974).

• Proposal for an Accelerator-Based Neutron Generator, BNL-20159, Brookhaven National Laboratory (1975).

Main storage requirements for the various processing codes are as follows:

• Data conversion program:     150K bytes

• Group boundary conversion:   150K bytes

• RECOIL:                      400K bytes.

MVS/SE.

T.A. Gabriel, J.D. Amburgey, N.M. Greene

ORNL, Oar Ridge, TN, USA