Studies of mixed HEU-LEU-MTR cores using 3D models
- Paul Scherrer Institute, Villigen (Switzerland)
Several different core loadings were assembled at the SAPHIR research reactor in Switzerland combining the available types of MTR-type fuel elements, consisting mainly of both HEU and LEU fuel. Bearing in mind the well known problems which can occur in such configurations (especially power peaking), investigations have been carried out for each new loading with a 2D neutron transport code (BOXER). The axial effects were approximated by a global buckling value and therefore the radial effects could be studied in considerably detail. Some of the results were reported at earlier RERTR meetings and were compared to those obtained by other methods and with experimental values. For the explicit study of the third dimension of the core, another code (SILWER), which has been developed in PSI for LWR power plant cores, has been selected. With the help of an adapted model for the MTR-core of SAPHIR, several important questions have been addressed. Among other aspects, the estimation of the axial contribution to the hot channel factors, the influence of the control rod position and of the Xe-poisoning on the power distribution were studied. Special attention was given to a core position where a new element was assumed placed near a empty, water filled position. The comparison of elements of low and high enrichments at this position was made in terms of the induced power peaks, with explicit consideration of axial effects. The program SILWER has proven to be applicable to MTR-cores for the investigation of axial effects. For routine use as for the support of reactor operation, this 3D code is a good supplement to the standard 2D model.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- OSTI ID:
- 567656
- Report Number(s):
- ANL/RERTR/TM-20; CONF-9409107-; ON: DE98000036; TRN: 98:003345
- Resource Relation:
- Conference: International meeting on reduced enrichment for research and test reactors, Williamsburg, VA (United States), 18-22 Sep 1994; Other Information: PBD: Aug 1997; Related Information: Is Part Of Proceedings of the 1994 international meeting on reduced enrichment for research and test reactors; PB: 427 p.
- Country of Publication:
- United States
- Language:
- English
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