BARC Newsletter Issue No. 249 Founder’s Day Special Issue 162 DESIGN AND FABRICATION OF PHOTOCHEMICAL REACTOR FOR SCALING UP OPERATION OF LASER ISOTOPE SEPARATION PROCESS P. Mathi, A.K. Nayak, V. Parthasarathy and S.K. Sarkar Laser & Plasma Technology Division Bhabha Atomic Research Centre and Lala Abhinandan and R. Bhatnagar Centre for Advanced Technology, Indore Introduction atural carbon consists of two stable isotopes, viz. C-13 (1.11%) and C-12 (98.89%). Carbon-13 is an important isotope as a tracer in chemistry, life sciences, medicine and biochemical synthesis. Although the current world production of C-13 at 90% concentration is about 10 kg per annum, an optimistic projection of hundred fold increase in the market demand is anticipated in view of rapid development of routine medical applications such as breath tests and whole body NMR. As a spin-off, C-13 depleted carbon (C-12 content 99.9%) can be used to make ‘super diamond’. The current method of C-13 separation by very low temperature ( -205 o C ) distillation of carbon monoxide has inherent drawbacks such as huge distillation tower, low separation factor, high energy consumption thus leading to a high production cost. In view of the growing demand for carbon isotopes, we are actively engaged in developing laser photochemical methods. Laser isotope separation (LIS) by infrared laser chemistry of polyatomic molecules has come a long way since its discovery. The process has been successfully demonstrated for the separation of isotopes of many light elements like hydrogen, carbon, oxygen, silicon and sulphur. The last decade has witnessed a considerable effort in scaling up of the process by adopting various strategies for improving both the throughput and separation factor [1]. The photochemical reactor (PCR) plays a major role in the process scaling up. In the present paper, we will highlight our current efforts in the design and fabrication of a PCR for the macroscopic separation of various isotopes. System Description Based on our laboratory scale studies [2], a prototype facility was built which has the following major components and the flow sheet for this process is given in Fig 1. 1. Laser and accessories include various optical elements like windows, gratings, mirrors, lenses etc, detectors of energy and temporal profile, oscilloscopes and control electronics. 2. Photochemical reactor (PCR) includes Herriott multipass refocusing cell (MPRF) in flow configuration with circulatory pump / blower, mass flow meter, metering valves, pressure transducer etc. 3. Product separator / collector include (i) cryogenic distillation column and (ii) preparative gas chromatograph. N