R-matrix evaluation of {sup 16}O neutron cross sections up to 6.3 MeV

Journal Article · Thu Dec 31 04:00:00 EST 1998 · Transactions of the American Nuclear Society

OSTI ID:298311

Leal, L C; Sayer, R O; Larson, N M; Spencer, R R ^[1]

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1. Oak Ridge National Laboratory, TN (United States)

The authors describe an evaluation of {sup 16}O neutron cross sections in the resolved resonance region with the multilevel Reich-Moore R-matrix formalism. Resonance analyses were performed with the SAMMY computer code, which utilizes Bayes` method, a generalized least-squares technique. Over the years the nuclear community has developed a collection of nuclear data for applications in thermal, fast reactor, and fusion systems. However, typical neutron spectra in criticality safety applications are different from the spectra relevant to thermal, fast reactor, and fusion systems. In fact, the neutron spectra important for these nonreactor systems appear to peak in the epithermal energy range. Nuclear data play a major role in the calculation of the criticality safety margins for these systems. A thorough examination of how the present collection of nuclear data behaves in criticality safety calculations is needed. Many older evaluations will probably need to be revised, and new evaluations will be needed. Oxygen is an important element in many criticality safety applications. The existing evaluation is expressed in terms of pointwise cross sections derived from the analysis of Hale et al. Unfortunately, such an evaluation is not directly useful for resonance analysis of data from samples in which oxygen is combined with other elements; for that purpose, Reich-Moore resonance parameters are needed. The authors address the task of providing those parameters.

• OSTI ID: 298311
• Report Number(s): CONF-981106--
• Journal Information: Transactions of the American Nuclear Society, Journal Name: Transactions of the American Nuclear Society Vol. 79; ISSN 0003-018X; ISSN TANSAO
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
66 PHYSICS
CRITICALITY
MEV RANGE 01-10
NEUTRON REACTIONS
OXYGEN 16 TARGET
R MATRIX
RESONANCE
TOTAL CROSS SECTIONS