Control Rod Calculation in Axially-Heterogeneous Fast Reactors. Part I: Influence of the Absorber Environment

• In axially heterogeneous fast reactor concepts, such as the ASTRID CFVcore, the accurate neutronic prediction of control rods is a challenge. In suchcores, the performance of the classical 2D equivalence procedure, used forcontrol rod homogenization in homogeneous fast reactors, is questionable.In this work (Part I of II), a number of axially heterogeneous environ-ments, representative of a CFV-type core are investigated using 2D (X-Z )models, with the objective to distinguish regions where the classical equiva-lence procedure is valid from those where it is not.It is found that the environments that affect the control rod absorber themost, and are likely to invalidate the procedure, are the internal control rodinterfaces, such as the absorber/follower interface and the interface betweenzones of different boron enrichments. The range of the main spectral impactcould be seen within 0-10 cm from the material interfaces studied.In a companion Paper (Part II), a full core investigation is performed,which builds upon the results of this paper.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Annan teknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Other Engineering and Technologies (hsv//eng)

Nyckelord

fast reactor

homogenization

Control rod

Publikations- och innehållstyp

art (ämneskategori)

ref (ämneskategori)