2007 International RERTR Meeting

Abstracts and Available Papers Presented at the Meeting

Thermal-Hydraulic Calculations for the Conversion to LEU of a Research Reactor Core

D. Grigoriadis^1,2, M. Varvayanni¹, N. Catsaros¹, E. Stakakis^1
1 National Center for Scientific Research "DEMOKRITOS" 153 10, Aghia Paraskevi, Greece
² Department of Mechanical and Manufacturing Engineering, University of Cyprus, P.O. Box 20537, Nicosia, 1678, Cyprus

ABSTRACT

The thermal-hydraulic analysis performed for the needs of the conversion of the open pool 5MW Greek Research Reactor (GRR-1) to a pure Low Enrichment (LEU) configuration is presented. The methodology was based on a complete set of neutronic calculations performed for the new core configuration, in compliance with pre-defined Operation Limiting Conditions. The hottest channel analysis approach was adopted, and peaking factors were used to account for fabrication or measuring uncertainties. Calculations were carried out using the numerical codes NATCON, PLTEMP and PARET provided by Argonne National Laboratory (Argonne). Two main different classes of conditions were considered, namely i) steady state normal operating conditions and ii) transient cases related to accidental events including reactivity feedback effects. For steady state operating conditions the behaviour of the new configuration was examined both for forced and natural convection cooling modes. Transient calculations considered several initiating events including reactivity insertion accidents (slow or fast reactivity insertion) and total or partial loss-of-flow accidents, i.e. in accordance to guidelines provided by the IAEA for research Reactors.

 

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