A simple and efficient procedure has been developed for the rapid and quantitative extraction of boron (B) from uranium-silicon-aluminium compounds, aided by generation of in-situ accelerator, employing pyrohydrolysis (PH) technique. The PH operating conditions like choice of carrier gas, heating time and sample mass were optimized for rapid and quantitative recovery of B. Inductively coupled plasma orthogonal acceleration time of flight mass spectrometer(ICP-oa-TOFMS)was utilizedfor the simultaneous determination of B content and its isotope ratio (¹⁰B/¹¹B). The ICP-oa-TOFMS operating parameters like acquisition time, mass bias, long- and short-term stabilities were optimized and common analyte internal standardization (CAIS) chemometric technique was applied to improve both the accuracy and precision of ¹⁰B/¹¹B ratio. The detection limit of the method for B was found to be 0.7μgL^-1. The proposed method for B quantification was validated by an independent spectro photometric technique. The accuracy on ¹⁰B/¹¹B ratio measurement was established by carrying out PH of a synthetic mixture of U₃O₈(free from B) and NIST SRM 951 followed by ICP-oa-TOFMS analysis of the distillate. XRD study of the sample before and after PH revealed the auto-acceleration ability of in-situ generated U₃O₈ phase on faster and efficient removal of analyte. The developed methodology was successfully applied for the analysis of five real samples of uranium silicide dispersed in aluminium matrix (U₃Si₂-Al) and three real uranium-silicon-aluminium alloy U(Al,Si)₃ samples. The relative standard deviations (1σ) on B content and ¹⁰B/¹¹B ratio in these samples were found to be within 3% and 0.16-0.27% respectively.