Isotope correlations for determining the isotopic composition of plutonium in high burnup pressurized water reactor (PWR) samples

Isotopic correlation for 242Pu composition prediction: Multivariate regresssion approach

“…The single isotope based correlation a b c d models (Swinhoe and Alamelu-1) do not predict even 10% of the TS samples with an accuracy of 2.5%. It was of interest to apply the multivariate models obtained using Indian PHWR's Pu isotopic data, to the data of Pu samples with high burnup (35.5-62.9 GWd/MtU) available in literature (Joe et al, 2010). It was observed that the PCR and PLSR models (mentioned in Sections 3.2 and 3.3) could not predict 242 Pu of Joe et al (2010) data with an accuracy of better than 5% in any of the samples (actually the deviation was 30-40%) whereas the MLR model (mentioned in Section 3.1) could predict 242 Pu atom% abundance with accuracy better than 0.7% in all the samples.…”

“…It was of interest to apply the multivariate models obtained using Indian PHWR's Pu isotopic data, to the data of Pu samples with high burnup (35.5-62.9 GWd/MtU) available in literature (Joe et al, 2010). It was observed that the PCR and PLSR models (mentioned in Sections 3.2 and 3.3) could not predict 242 Pu of Joe et al (2010) data with an accuracy of better than 5% in any of the samples (actually the deviation was 30-40%) whereas the MLR model (mentioned in Section 3.1) could predict 242 Pu atom% abundance with accuracy better than 0.7% in all the samples. This can be attributed to the fact that the contribution of 238 Pu atom% in the PC1 to PC3 (in case of PCR) and in Factor-1 to Factor-3 (in case of PLSR) is negligible and hence has hardly any influence on prediction capability; whereas the MLR model used the 238 Pu information to full extent.…”

“…However, different isotope correlations are reported in literature for the determination of 242 Pu in Pu samples using other Pu isotopes abundances. These correlations have been developed based on Pu IC data obtained by different methods such as TIMS, α-S, liquid scintillation counting, neutron coincidence counting (Aggarwal et al, 1998;Aggarwal, 2001, 2007;Alamelu et al, 2010;Bignan et al,1998;De Regge and Bodden, 1978;Joe et al, 2010;Kumar et al, 2008;Li et al,1991aLi et al, , 1991bLi et al, , 1997Nishida et al,1992;Sampson et al,1980;Schubert and Ottmar, 1987;Swinhoe et al, 2010,) etc. Depending on the different reactor burn-ups, these correlations are also different Aggarwal, 2001, 2007;Alamelu et al, 2010;Bignan et al, 1998).…”