Assessment of fissionable material behaviour in fission chambers

Abstract

Keywords:Fission chamber BR2 DEMO IFMIF Uncertainty cross-sections A comprehensive study is performed in order to assess the pertinence of fission chambers coated with different fissile materials for high neutrón flux detection. Three neutrón scenarios are proposed to study the fast component of a high neutrón flux: (i) high neutrón flux with a significant thermal contribution such as BR2, (ii) DEMO magnetic fusión reactor, and (iii) IFMIF high flux test module.In this study, the inventory code ACAB is used to analyze the following questions: (i) impact of different deposits in fission chambers; (ii) effect of the irradiation time/burn-up on the concentration; (iii) impact of activation cross-section uncertainties on the composition of the deposit for all the range of burn-up/irradiation neutrón fluences of interest. The complete set of nuclear data (decay, fission yield, activation cross-sections, and uncertainties) provided in the EAF2007 data library are used for this evaluation.

Study on the response of IFMIF fission chambers to mixed neutron-gamma fields: PH-2 experimental tests

“…It is important to notice the influence of the cross section uncertainties in the predicted value. Calculations performed for a 238 U deposit showed that, in BR2 conditions, it could lead to 14% relative error in sensitivity to fast neutrons [5].…”

Improvements in the Modeling of Sub-Miniature Fission Chambers Operated in Current Mode

“…Three boundary conditions complete (2): (a) the electronic density is zero at the cathode surface, (b) the ionic density is zero at the anode surface, (c) a voltage difference, , being applied between anode and cathode for charge collection, we have (3) where is any possible path linking the anode to the cathode. Using a perturbation method, we had obtained analytical solutions for (2) with boundary conditions (a) to (c).…”

“…Because of their reduced volume and their robustness, SMF chambers have become standard power monitors in many commercial and research nuclear reactors. Their use is extending to other neutron sources, such as spallation targets, and is under investigation for the monitoring of fusion devices [1]- [3].…”

Influence of thermal and resonance neutron on fast neutron flux measurement by 239 Pu fission chamber

“…Fission chambers are widely used in online neutron flux measurement. It could be adopt for not only the fission neutron field but also the fusion neutron field [3].…”