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Because of the possible enhanced deuterium abundance of D/H = 2.5 $10^{-4}$ (the ISM D/H = 1.65x$10^{-5}$) recently reported in quasar absorption spectra, we searched for the D$_\alpha$ line at 6561 A in the metal-poor halo star HD 140283 (G2IV, [Fe/H] = -2.6; T$_{eff}$= 5700K). We observed HD 140283 using the .9m KPNO coude feed and the 2.7m McDonald Observatory telescopes with echelle spectrographs having a resolution $\Delta\lambda$ = .05 A/pixel with S/N= 200 and $\Delta\lambda$ = .11 A/pixel with S/N = 600 respectively. We did not detect the D$_\alpha$ line and compared our results to model atmosphere calculations for this star. We estimate an upper limit of D/H $<$ 1x$10^{-5}$ which is smaller than the primordial or and Early Galactic D/H = 8x$10^{-5}$. Since D is destroyed via reactions with protons at T $>$ 5x$10^5$K, the atmospheric deuterium has probably been destroyed during the pre-main sequence convection phase. Because $^7$Li, $^9$Be, and $^{11}$B have all been detected in this star (Li/H=1.5x$10^{-10}$ and B/H=2.9x$10^{-12}$) and Li is destroyed at T $>$ 2.5x$10^6$K, the temperature at the bottom of the pre-main sequence convection zone is 1x$10^6$K $<$ T $<$ 2.5x$10^6$.K
