Nuclear PWR Plants Life Management Reactor Pressure Vessel Strategy Evaluation for Fluence in Relation With Integrity Assessment

Abstract

The French utility has organized the life management program of Nuclear Plants in function of several actions: • Fluence assessment, • Material characteristic and RTndt at the end of life, • Transient evaluation, • Integrity assessment, • Life management and maintenance strategy. This paper shows the studies engaged to evaluate and the monitoring on the fluence evaluation and flux factor assessment. Also this paper shows the axial and azimuthally variation of fluence studies and how these results were coupled with in-service inspection and integrity assessment. The applications were for 3-loop PWR plants and also 4-loop PWR PLANTS. The monitoring was mainly oriented on evaluation of the ratio computation and measurement on dosimetry introduced in irradiation surveillance program capsules that were withdraw after irradiation inside vessel. Some results on comparison between measurements and calculation of flux factors are presented. A discussion on good comparison on values obtained for all reactor pressures vessels from this comparison between flux factors calculations and measurements indicate that this strong methodology gives good results on RPV neutron studies.