Abstracts and Available Papers Presented at the
1998 International RERTR Meeting

ANALYSIS OF Mo99 PRODUCTION IRRADIATING 20 %U TARGETS

R. CALABRESE, C. GRANT, A. MARAJOFSKY, D. G. PARKANSKY

Comisión Nacional de Energía Atómica
Buenos Aires, Argentina

ABSTRACT

At present time, CNEA is producing about 800 Ci of Mo99 per week irradiating 90% enriched uranium - aluminum alloy plate targets in the RA3 reactor, a 5 Mw. MTR type one. In order to change to 20% enriched Uranium, and to increase the production to about 3000 Ci per week, some configurations were studied with rod and plate geometry with uranium (20% enriched) - aluminum targets.

The first case was the irradiation of a plate target element in the normal reactor configuration. Results showed a good efficiency, but both reactivity value and power density were too high.

An element with rods was also analized, but results showed a poor efficiency, too much aluminum involved in the process, although a low reactivity and an acceptable rod power density.

Finally, a solution consisting of plate elements with a Zircalloy clading was adopted, which has shown not only a good efficiency, but it is also acceptable from the viewpoint of safety, heat transference criteria and feasibility.