Analysis methods for the determination of possible unseated fuel assemblies in BWRs
by Christophe Demaziere
International Journal of Nuclear Energy Science and Technology (IJNEST), Vol. 2, No. 3, 2006

Abstract: This paper describes noise-based methods, the purpose of which is to determine whether the core of a Boiling Water Reactor (BWR) contains unseated fuel assembly(ies) or not. The characteristic feature of an unseated fuel assembly is to render the corresponding fuel channel thermal-hydraulically unstable since some of the coolant bypasses the fuel channel. The induced neutron noise has a strong space-dependence due to the localised character of the perturbation. Several techniques relying on the analysis of the spatial structure of the in-core neutron noise can thus be used to determine whether the induced neutron noise might correspond to unseated fuel assembly(ies). These techniques rely on time-domain and frequency-domain analyses. This paper presents in all cases expected spatial signatures determined from calculations, and compares these theoretical findings to two practical examples, where noise measurements were carried out: a local instability event, and a global oscillation coexisting with a regional oscillation.

Online publication date: Sun, 20-Aug-2006

The full text of this article is only available to individual subscribers or to users at subscribing institutions.

Existing subscribers:
Go to Inderscience Online Journals to access the Full Text of this article.

Pay per view:
If you are not a subscriber and you just want to read the full contents of this article, buy online access here.

Complimentary Subscribers, Editors or Members of the Editorial Board of the International Journal of Nuclear Energy Science and Technology (IJNEST):
Login with your Inderscience username and password:

    Username:        Password:         

Forgotten your password?

Want to subscribe?
A subscription gives you complete access to all articles in the current issue, as well as to all articles in the previous three years (where applicable). See our Orders page to subscribe.

If you still need assistance, please email