Abstracts and Available Papers Presented at the
1999 International RERTR Meeting

THERMAL HYDRAULIC AND SAFETY ANALYSES FOR
 PAKISTAN RESEARCH REACTOR-1

by

I. H. BOKHARI, M. ISRAR, S. PERVEZ
Nuclear Engineering Division
Pakistan Institute of Nuclear Science and Technology
P.O. Nilore, Islamabad, Pakistan

To be presented at:

 22^nd International Meeting on
Reduced Enrichment for Research and Test Reactors (RERTR)
4-8 October, 1999, Budapest, Hungary

ABSTRACT

Thermal hydraulic and safety analysis of Pakistan Research Reactor-1 (PARR-1) utilizing low enriched uranium (LEU) fuel have been performed using computer code PARET. The present core comprises of 29 standard and 5 control fuel elements. Results of the thermal hydraulic analysis show that the core can be operated at a steady-state power level of 10 MW for a flow rate of 950 m³/h, with sufficient safety margins against ONB (onset of nucleate boiling) and DNB (departure from nucleate boiling). Safety analysis has been carried out for various modes of  reactivity insertions. The events studied include: start-up accident;  accidental drop of a fuel element in the core; flooding of a beam tube with water; removal of an in-pile  experiment during reactor operation etc. For each of these transients, time histories of reactor power, energy released and clad surface temperature etc. were calculated. The results indicate that the peak clad temperatures remain well below the clad melting temperature during these accidents. It is therefore concluded that the reactor can be safely operated at 10 MW without compromising safety.

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