Physics and Chemistry of Glasses: European Journal of Glass Science and Technology Part B Volume 51 Number 4 August 2010 217 Phys. Chem. Glasses: Eur. J. Glass Sci. Technol. B, August 2010, 51 (4), 217–225 Introduction In view of the greenhouse effect, global warming and limited resources of fossil fuel, nuclear energy is one of the cleanest options to meet the growing energy demands of developing countries. However, in the course of the nuclear fuel cycle a lot of radioactive waste is generated whose handling poses a serious challenge to nuclear engineers and scientists. Most of the radioactivity of the entire nuclear fuel cycle is concentrated in the so-called high level radioactive liquid waste (HLW). The major sources of radiation are the alphas from residual actinides and betas from fission/activation products. The accepted approach for HLW management today is to concentrate and fix the waste in suitable matrices like glasses, tailor made synthetic ceramics (Synroc) and naturally oc- curring minerals like zircon. (1–3) Borosilicate based glass formulations have been adopted worldwide as a suitable matrix for immobilizing the HLW. (4–6) These glasses possess desirable properties like high chemical, mechanical, thermal and radiation stabil- ity for HLW storage. Also, the amorphous nature of the glass helps to easily accommodate the waste containing a variety of elements. However, the glass composition varies with the composition of the HLW, which in turn depends on the type of reactor, burn up, off reactor cooling of spent nuclear fuel and nature of reprocessing flow sheets, etc. Although the basic network is of silicon and boron oxides, other modi- fiers are necessary to take into account site specific variations in HLW composition. In BARC, Trombay, the present HLW from research reactors is characterized by the presence of high amounts of sulfate ions and sodium along with fis- sion and activation products, corrosion products and actinides. Sulfate ions in the waste are derived from ferrous sulfamate [Fe(NH 2 SO 3 ) 2 ] used as a reducing agent for the conversion of Pu 4+ to Pu 3+ at the parti- tioning stage of the actinides during reprocessing and is one of the troublesome constituents with respect to vitrification in view of its limited solubility in the glass matrix. (7) To deal with this, a barium oxide con- taining alkali borosilicate glass has been developed and is routinely used for waste immobilization. (8) The quaternary system of BaO–Na 2 O–B 2 O 3 –SiO 2 referred to as base glass is found to be suitable in dealing with the problem of sulfate ions forming a separate phase without affecting the waste oxide loading. The spectroscopic properties of various metal ions likely to be present in the Trombay waste glass are not known. Through this paper an aempt has been made to investigate the spectroscopic properties of different transition metal ions namely Cr, Cu, Fe and Mn in the barium based sodium borosilicate glass by various spectroscopic techniques. Cr, Fe and Mn are Spectroscopic investigation of transition metal (Cr, Cu, Fe, and Mn) containing Trombay waste base glass M. Mohapatra, 1,4 R. M. Kadam, 1 S. N.Tripathy, 2 A. R. Dhobale, 1 R. K. Mishra, 3 C. P. Kaushik, 3 B. S. Tomar, 1 Kanwar Raj, 3 S. V. Godbole 1,4 & V. K. Manchanda 1 1 Radiochemistry Division, 2 Bio Organic Division, 3 Waste Management Division, Bhabha Atomic Research Centre (BARC), Mumbai-400085, India Manuscript received 4 September 2009 Revised version received 23 March 2010 Accepted 30 March 2010 Absorption and electron paramagnetic resonance (EPR) investigations were carried out on barium based alkali borosili- cate glasses in order to characterize the oxidation states and coordination behaviour of several transition metal ions in them, namely Cr, Cu, Fe and Mn. The glass composition was similar to that of the Trombay waste base glass used for vitrification of research reactor high level waste (HLW). It was observed that Cr is stabilized in the glass matrix in two oxidation states namely 3+ and 5+ in distorted octahedral geometries. The Racah parameter value was calculated from the absorption studies. Cu ions in the borosilicate glass get stabilized as Cu 2+ where the lone electron resides in d x2−y2 orbital. It was found that the Cu ions are interacting via a paramagnetic interaction through the oxygen linkage. From the correlation of the absorption and EPR data, bonding parameters were evaluated for the system. In case of Fe-glass it was found that iron gets stabilized in 3+ oxidation state both in tetrahedral and octahedral geometries. In case of Mn incorporated barium borosilicate glass, it was found out that, apart from the usual 2+ oxidation state, Mn gets stabilized in the matrix in the form MnO 4 − and MnO 4 2− . 4 Corresponding authors. Email manojm@barc.gov.in and svgod@barc. gov.in