Nuclear Engineering and Design 236 (2006) 770–783 Multi purpose research reactor V.K. Raina a,∗ , K. Sasidharan a , Samiran Sengupta a , Tej Singh b a Research Reactor Design & Projects Division, Bhabha Atomic Research Centre, Mumbai 400085, India b Research Reactor Services Division, Bhabha Atomic Research Centre, Mumbai 400085, India Received 11 March 2004; received in revised form 26 September 2005; accepted 28 September 2005 Abstract At present Dhruva and Cirus reactors provide the majority of research reactor based facilities to cater to the various needs of a vast pool of researchers in the field of material sciences, physics, chemistry, bio sciences, research & development work for nuclear power plants and production of radio isotopes. With a view to further consolidate and expand the scope of research and development in nuclear and allied sciences, a new 20 MWt multi purpose research reactor is being designed. This paper describes some of the design features and safety aspects of this reactor. © 2006 Elsevier B.V. All rights reserved. 1. Introduction High flux research reactors play a crucial role in providing unique facilities for basic research in frontier areas of science and for applied research related to development and testing of nuclear fuels and other materials. These reactors also cater to the increasing need of radioisotopes for application in the fields of medicine, agriculture and industry. Keeping in view the projected requirements of reactor based facilities for basic and applied research as also the projected demand for radioisotopes in the country, construction of a new “multi purpose research reactor” (MPRR) is essential. The MPRR with its high neutron flux and irradiation vol- ume will provide the appropriate platform for research in reactor fuels, reactor materials, condensed matter research for study of structure and dynamics of materials, stress analysis of engineer- ing components especially reactor materials, dynamic radio- graphy, time of flight refractrometry, small sample investiga- tions for the study of new and novel materials such as ferro- magnetic, opto-electric materials, protein crystals, fullerenes, porous-silicon, etc., including high pressure and milli-Kelvin range studies which will greatly help the nation to keep abreast of the developments in the field of material sciences and devel- opment of novel materials and alloys. ∗ Corresponding author. Tel.: +91 22 25594608; fax: +91 22 25505311. E-mail address: vkrain@magnum.barc.ernet.in (V.K. Raina). The MPRR will supplement the isotope production capacity of Dhruva research reactor to meet the projected requirements of various isotopes beyond the year 2010. Installation of a xenon gas loop, for production of I-125, which has a great demand for medical and industrial applications, is also being explored. The proposed 20 MWt research reactor will have a maxi- mum thermal neutron flux of 5 × 10 14 n/cm 2 /s. The reactor will be fuelled with Low Enriched Uranium dispersion type fuel and will use light water as coolant and moderator. The reactor core will be surrounded by an annular heavy water tank to achieve a high neutron flux and irradiation volume to maximize the num- ber of irradiation positions available for isotope production and material irradiation. Most of the irradiation positions will be accommodated in the heavy water reflector tank surrounding the core. 2. Physics design 2.1. Design objective The primary objective of the nuclear design of the MPRR is to obtain high usable thermal and fast neutron (>821 keV) flux levels in experimental/irradiation positions, low nuclear fuel inventory, minimum number of reactivity control devices, optimal fuel thermal hydraulics and high reactivity safety mar- gins. Design also caters to experimental and irradiation reactivity loads as well as operational reactivity requirements, fuel burn-up and xenon over-ride. 0029-5493/$ – see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.nucengdes.2005.09.022