Validation model for the transient analysis of tightly coupled reactors
- Massachusetts Inst. of Technology, Cambridge, MA (United States)
Both the static and transient analysis of tightly coupled reactors differ from those of the loosely coupled systems. In these reactors, highly absorbing regions are interspaced with low absorbing regions. That raises questions of the acceptability of diffusion theory approximations. Also, the spectral shapes change drastically throughout the core and can be altered significantly by perturbations. Accurate analysis requires at least two-dimensional, multigroup transport methods. Although, such methods can be applied for static cases, for transient analysis they would be almost impossibly expensive. Recently a transient nodal model accounting for transport corrections has been developed for tightly coupled reactors. In this model, few-group, node-averaged cross sections and discontinuity factors are edited from full-core, higher order reference results such as Monte Carlo or fine-mesh, multigroup, discrete ordinate transport solutions for various conditions expected during transients. Tables of nodal parameters are constructed, and their values as the transient proceeds are found by interpolation. Although the static part of this few-group model can be tested easily by comparing nodal results with the reference transport solution, without a time-dependent transport code (at least a two-dimensional, multigroup, discrete ordinate code), doing the analogous validation for the time-dependent problem is not possible.
- OSTI ID:
- 426520
- Report Number(s):
- CONF-961103-; ISSN 0003-018X; TRN: 96:006307-0249
- Journal Information:
- Transactions of the American Nuclear Society, Vol. 75; Conference: Winter meeting of the American Nuclear Society (ANS) and the European Nuclear Society (ENS), Washington, DC (United States), 10-14 Nov 1996; Other Information: PBD: 1996
- Country of Publication:
- United States
- Language:
- English
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