The Limits of Safety Analysis: Severe Nuclear Accident Possibilities at the PFBR

Ashwin Kumar ([email protected]) is a PhD scholar at the department of engineering and public policy, Carnegie Mellon University, Pittsburgh, US. M V Ramana (ramana@ princeton.edu) is with the Program on Science and Global Security, Woodrow Wilson School of Public and International Affairs, Princeton University, Princeton, US. The Prototype Fast Breeder Reactor that is being built in Kalpakkam in Tamil Nadu has the potential to undergo severe accidents that involve the disassembly of the reactor core. Such accidents could release sufficient energy to fracture the protective barriers around the core, including the containment building, and release large fractions of the radioactive material in the reactor into the surroundings. The designers of the PFBR have made choices aimed at making the reactor cheaper rather than safer. The safety assessment of the PFBR points to some fundamental problems with how nuclear technology is regulated. In September 2011, the director of the Indira Gandhi Centre for Atomic Research (IGCAR) announced that the centre had finalised the design of commercial fast breeder reactors to be built at Kalpakkam (Tamil Nadu) and elsewhere (PTI 2011). This design is reportedly modified from that of the Prototype Fast Breeder Reactor (PFBR), also being built in Kalpak kam, with an eye towards lowering the cost of construction. This should be of concern because even the PFBR is unsafe by being unprotected against severe accidents, despite assurances to the contrary offered by the nuclear establishment (Subramanian 2011). The main problem with the PFBR is that its containment design does not protect adequately against severe accidents that can occur. Furthermore, design choices made by the IGCAR at Kal pakkam have made such accidents more likely and also potentially more destructive. Equally troubling is the inadequacy of the safety analyses performed by the IGCAR, which bases its analyses on optimistic a ssumptions about the conditions prevailing in the reactor during a severe accident. Because the PFBR is to be the first of many of its kind, the IGCAR’s design of this r eactor is likely to influence subsequent developments. The reasons for the above assertions have been discussed at length in our 2008 article published in the journal Science and Global Security (Kumar and Ramana 2008).1 In response to this article and to a subsequent summary article by us in the Bulletin of the Atomic Scientists (Kumar and Ramana 2009),2 Baldev Raj, former director of the IGCAR, wrote a letter in Science and Global Security seeking to rebut our assertions (Raj 2009).3 Although we welcomed the response, it did not address the issues we raised. Our counter-response describes what the IGCAR’s response lacked (Kumar and Ramana 2009).4 IGCAR did not respond to our counter-response, and in essence ignored it. Indeed, when a prominent columnist wrote an article in the Times of India in March 2011 in the context of the then ongoing Fukushima accidents pointing out that there are even greater safety concerns about fast reactors, the Nuclear Power Corporation (NPC) put up an article by Baldev Raj and Prabhat Kumar on its website that simply reiterated some of the points made in Baldev Raj’s response without seeking to engage our arguments (NPC 2011). It did not even mention that we had refuted these points. In this article we discuss the potential for severe accidents at the PFBR and lacunae in its design, as well as problems with