Conversion of the WSU reactor to a mixed core of TRIGA- FLIP and ...
Conversion of the WSU reactor to a mixed core of TRIGA- FLIP and ...
Conversion of the WSU reactor to a mixed core of TRIGA- FLIP and ...
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The <strong>the</strong>rmal flux levels in <strong>the</strong> most commonly used experimentalfacilities increased between 257o <strong>and</strong> 307 o as a result<strong>of</strong> <strong>the</strong> conversion. Measurements made with a self-powered neutrondetec<strong>to</strong>r indicated a peak flux <strong>of</strong> ~8.5 x 1012nv in <strong>the</strong>vertical wet tube located in Grid Position D-8. Measurementsin <strong>the</strong> same position prior <strong>to</strong> <strong>the</strong> <strong>core</strong> change revealed a level12<strong>of</strong> ^6.0 x 10 nv at <strong>the</strong> peak. The improvement <strong>of</strong> <strong>the</strong> experimentalfacility flux level met <strong>the</strong> anticipations from preconversioncalculations <strong>and</strong> analysis.Operation <strong>of</strong> <strong>the</strong> <strong>reac<strong>to</strong>r</strong> since initial startup with <strong>the</strong><strong>mixed</strong> <strong>core</strong> has <strong>to</strong>talled only forty megawatt-days. The rate <strong>of</strong>excess reactivity loss over this operating period has beencalculated at $0,011 per megawatt day, reflecting <strong>the</strong> accumulation<strong>of</strong> primary poisons in <strong>the</strong> <strong>FLIP</strong> fuel. More data fromcontinuing operations will be necessary <strong>to</strong> determine an equilibriumrate <strong>of</strong> excess loss.In summary, <strong>the</strong> observed performance <strong>of</strong> <strong>the</strong> <strong>mixed</strong> <strong>core</strong>has been quite satisfac<strong>to</strong>ry <strong>and</strong> analysis has indicated nosignificant deviations from <strong>the</strong> design predictions <strong>and</strong> specifications.No major operational problems have developed since<strong>the</strong> conversion was completed.3-25