A consistent, differential versus integral, method for measuring the delayed neutron yield in fissions
- CEA, Cadarache (France)
- Tsinghua Univ., Beijing (China)
- ENEA, Roma (Italy)
Due to the persistent uncertainties: {approximately} 5 % (the uncertainty, here and there after, is at 1{sigma}) in the prediction of the `reactivity scale` ({beta}{sub eff}) for a fast power reactor, an international project was recently initiated in the framework of the OECD/NEA activities for reevaluation, new measurements and integral benchmarking of delayed neutron (DN) data and related kinetic parameters (principally {beta}{sub eff}). Considering that the major part of this uncertainty is due to uncertainties in the DN yields (v{sub d}) and the difficulty for further improvement of the precision in differential (e.g. Keepin`s method) measurements, an international cooperative strategy was adopted aiming at extracting and consistently interpreting information from both differential (nuclear) and integral (in reactor) measurements. The main problem arises from the integral side; thus the idea was to realize {beta}{sub eff} like measurements (both deterministic and noise) in `clean` assemblies. The `clean` calculational context permitted the authors to develop a theory allowing to link explicitly this integral experimental level with the differential one, via a unified `Master Model` which relates v{sub d} and measurables quantities (on both levels) linearly. The combined error analysis is consequently largely simplified and the final uncertainty drastically reduced (theoretically, by a factor {radical}3). On the other hand the same theoretical development leading to the `Master Model`, also resulted in a structured scheme of approximations of the general (stochastic) Boltzmann equation allowing a consistent analysis of the large range of measurements concerned (stochastic, dynamic, static ... ). This paper is focused on the main results of this theoretical development and its application to the analysis of the Preliminary results of the BERENICE program ({beta}{sub eff} measurements in MASURCA, the first assembly in CADARACHE-FRANCE).
- OSTI ID:
- 459149
- Report Number(s):
- CONF-950420-; TRN: 97:007058
- Resource Relation:
- Conference: International conference on mathematics and computations, reactor physics, and environmental analyses, Portland, OR (United States), 30 Apr - 4 May 1995; Other Information: PBD: 1995; Related Information: Is Part Of Proceedings of the international conference on mathematics and computations, reactor physics, and environmental analyses. Volume 1 and 2; PB: 1629 p.
- Country of Publication:
- United States
- Language:
- English
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