Published online by Cambridge University Press: 06 March 2019
In nuclear power plants the fast neutron fluence on the pressure vessel (PV) inner wall is measured by the scraping sampling method (1). As the inner plating of the pressure vessel contains 0.5 - 0.6 % of niobium, 93mNb (tt/2 = 16a) isomer is produced by the reaction 93Nb (n, n’). The activity of 93mNb is related to the fast neutron fluence.
Scraping samples (few hundred of mg) were taken from the PV inner wall. The niobium was chemically extracted from steel by using a HAP column. This extraction was needed to reduce matrix effects and to avoid interferences of other activities with 93mNb