International Reactor Dosimetry File 2002 - IAEA Publications

2. NEW RUSSIAN EVALUATIONS FOR IRDF-2002
K.I. Zolotarev
The contributions of the Institute of Physics and Power Engineering
(IPPE), Obninsk, Russian Federation, to IRDF-2002 are summarized below.
The 93 Nb(n,n¢) 93 Nb m and 93 Nb(n,2n) 92 Nb m reactions were taken from
RRDF-98 [2.1]. Fourteen reactions from RRDF-98 were revised and corrected
following the recommendations made by Zsolnay et al. [2.2]; these reactions
are: 19 F(n,2n) 18 F, 46 Ti(n,2n) 45 Ti, 46 Ti(n,p) 46 Sc m+g , 47 Ti(n,x) 46 Sc m+g , 48 Ti(n,p) 48 Sc,
48 Ti(n,x) 47 Sc, 49 Ti(n,x) 48 Sc, 51 V(n,α) 48 Sc, 54 Fe(n,α) 51 Cr, 54 Fe(n,2n) 53 Fe m+g ,
59 Co(n,α) 56 Mn, 63 Cu(n,α) 60 Co m+g , 75 As(n,2n) 74 As and 141 Pr(n,2n) 140 Pr. A
further nine new evaluations were undertaken: 27 Al(n,p) 27 Mg, 56 Fe(n,p) 56 Mn,
58 Ni(n,p) 58 Co, 103 Rh(n,n¢) 103 Rh m , 115 In(n,n¢) 115 In m , 139 La(n,γ) 140 La,
186 W(n,γ) 187 W, 204 Pb(n,n¢) 204 Pb m and 237 Np(n,f).
Cross-section data were not provided in IRDF-90.2 [2.3] for the reactions
46 Ti(n,2n) 45 Ti, 49 Ti(n,x) 48 Sc, 54 Fe(n,2n) 53 Fe m+g , 54 Fe(n,α) 51 Cr, 75 As(n,2n) 74 As,
139 La(n,γ) 140 La, 186 W(n,γ) 187 W, 141 Pr(n,2n) 140 Pr and 204 Pb(n,n¢) 204 Pb m .
Activation detectors based on the 139 La(n,γ) 140 La and 186 W(n,γ) 187 W reactions
are commonly used in reactor dosimetry for determination of the neutron flux
in the epithermal energy range. The 204 Pb(n,n¢) 204 Pb m reaction would appear to
be of use for a neutron spectrum unfolding in the energy above 2.2 MeV. The
46 Ti(n,2n) 45 Ti and 54 Fe(n,2n) 53 Fe m+g reactions appear to be useful for neutron
dosimetry with T(d,n) 4 He as the sources. The 49 Ti(n,x) 48 Sc, 75 As(n,2n) 74 As and
141 Pr(n,2n) 140 Pr threshold reactions as well as the
47 Ti(n,x) 46 Sc m+g and
48 Ti(n,x) 47 Sc reactions may be useful for high energy neutron dosimetry. As
well as their adoption in dosimetry, the 75 As(n,2n) 74 As and 141 Pr(n,2n) 140 Pr
reactions are also used in experimental nuclear physics as monitor reactions for
the measurement of unknown cross-sections in the neutron energy range 14–
15 MeV.
Three information sources were consulted in the preparation of the input
data for the evaluation of cross-sections and their uncertainties: available
differential and integral experimental data, results of theoretical model calculations
and predictions of the systematics. Differential and integral experimental
data were taken from the EXFOR library (version of May 2003) and from the
original publications. As a first step in the evaluation procedure, all experimental
data were thoroughly analysed and, where possible, corrected to
conform to the recommended cross-section data for monitor reactions used in
the measurements, and also to the recommended decay data. The correction of
experimental data to conform to the new standards results in general in a
decrease in the discrepancies between the experimental data and the evaluated
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