Abstract Borosilicate glass is the most widely used burnable poison material in PWR. The boron isotope composition in the product can be used for fuel consumption estimation and product quality determination. In this paper ， boron isotope composition was studied based on direct melt thermoelectric ionization mass
spectrometry. First ， we discussed the influence of silicon impurity on the measurement results of boron isotope in boric acid. The results showed that silicon had no significant interference to the measurement results of NIST 951a boric acid standard material when Si/B mass ratio was less than 9 ， which verified the
feasibility of the direct melt thermoelectric ionization mass spectrometry for the determination of boron isotope composition in borosilicate glass. Then ， the effects of three parameters ， namely the molar ratio of Na/B ， mannitol and graphite addition amount were analyzed in detail ， and the best analysis condition were obtained as that the molar ratio of Na/B was 9 and the graphite addition amount was 3 μL with the addition of mannitol. Based on the above optimal test parameters ， the actual borosilicate glass samples were tested ，the correction of mass fractionation was carried out using NIST 951a boric acid as the external standard to obtain the final determination value of boron isotope ratio of samples. It was found that the uncertainty of the sample after fractionation correction was mainly from the standard material. The research results canprovide reference for the burn-up estimation of borosilicate glass and the quick determination of product
TANG Shuting,ZHANG Tianrui,YAN yan, et al. Determination of Boron Isotope Ratio in Borosilicate Glass by Direct Melting with Thermal Ionization Mass Spectrometry[J]. URANIUM GEOLOGY, 2020, 36(03): 199-206.