THE FUTURE OP ATOMIC POWER By B.D, Nag Ghaudhuri* AbBtract In this paper an attempt has been made to spell out the future plan of development of atomic power In India. It is pointed out that the programmes should be initiated towards the development of those advanced reactor concepts which ensure an optinua utilisation of our resources of both fissile and fertile material*. With the functioning of the Tarapur reactor and wi\Jn the Rajasthan and Kalpakkam reactors well on the way, nuclear reactors for the Bupply of electric power have come to stay in our country. It is therefore appropriate for us to enquire as to how do we eventually achieve a viable power reactor programme so that in the foreseeable future - say, 20 or 30 years from now - the atomic power plays an appro- priate role in the national economy. The problems are known, the baeic technologies are mastered or are already under study. We know what the tasks are and presumably how to set about it. What we need to do now is to lay down clearly what we wiBh our state of nuclear technology and nuclear power to be in say 1990 or 2000 AD and work backwards to the present so that the problems are clearly identifiedo It is only through the isolation of these identified problems and Initiating work en them right now that we can hope to achieve our goals In the future. This brings us immediately to the basic philosophy - often propagated In the country, but rarely acted upon - the advantages or otherwise of leapfrog- ging into appropriate technologies, in this case for atomic power, rather than chasing the tail of established technologies which (most of) our atomic power programmes seemingly do* If we have the courage to take * Member (Science), Planning Commission, Government of India, 27 27G advantages of leapfrogging we cnn establish f ar a toraic power In India an adequate role in tte future. It also provides a scientific and tech- nological challenge of earn magnitude. Because the challenge is largely in tRchnolofty and science contentf the employment potential of high calibro perMonnol ie also high if we accept these taskso It is fortuna- tely not nttcef-fi-nily equally high in investments. 2. There aiv> ratiny ideas and throughts that have been propagated by many people in the area of atomic power. Some of these are high tempera- ture reactors, direct conversion of heat to electrical power, breeding, fusion etc. These rnny be summed up an: (a) Reduction in capital costs thx%ough reduction in construction costs and methods and materials to give longer life to plants. (b) Reduction in fuel costs through higher thermal efficiencies, lower fuel costs and higher burnup (breeding). (c ) Reduction of power generation costs through deduction of costs of Pu-239 and U-233 as a result of techr.icul improve- ments in fuel reprocessing, 3. There haf not been substantial improvement in construction tech- nology but some lowering trends of cost6 have been noticed through develop- ment of material whose properties do not deteriorate rapidly with radia- tion damage. The possibility of breeding nuclear fuels from fertile material has been established in many countries of the world such as U.K., U.S.A.i U.S.S.R. and Prance. This is the area where substantial reduction of costs and better fuel utilisation seem entirely feasible. Several nations are working on what are essentially pilot breeding reactors in which some experiment on the possibility of using them for power is being carried out. This large effort in several countries on breeding experi« orente were firstly to establish the principle , which has been done, and secondly, to develop the necessary techniques to utilise these principles for producing power and lowering its costs. The approach is based on the fact that a derived fissile material such as Pu~239 or 1^-233 ie necessary to make it possible to use the much larger resources of fertile material 279 that are available in the world, and incidentally also in oar own country. The only natural fieaile material 1B the 0.1% of nornal ura- nium, U-235. The rest of normal uranium is 99.3# U-238 a fertile material. Thorium Is essentially a fertile material and not a fissile material. Thorium is about four or five times more plentiful than ura- nium. This gives LUB a ratio of one unit of fissile material to cover 700 units of fertile material in our natural resources. Low utilisation of fertile material results in low burraip and higher fuel coatB. Pieeile materials can be produced from these 700 ciniBB more abundant fertile material normally to a araall extent, but to more than the equivalent lose of U-2?i> only if we deliberately choose and make the effort to do so. Both of the fertile materials uranium and thorium remain to a large ex- tent unused or unusable unlpps deliberate policies of development and use of appropriate combinations of fertile material derived fissile material and normal fissile material in the use of projected reactor programme?) are taken up. In normal reactors the normal fissile material 0-235 pro- duces tone amount of a derived fissile material Pu-*39 from the fertile VS~^J>8. This varies depending on the design and the neutron economy of the reactor. In properly designed heavy water reactors the production of derived fissile material can reach to around 909& of the U-235 lost in producing po"«r. In most cases it is much less. \"e are faced with los- ing the potential of our fertile material if we dG not hpve well con- ceived programmes of utilising this potential. Since the development of these techniques encompasses several disciplines and ie somewhat mare sophisticated it will take a little time and effort before we can develop acceptable power reactors on this principle. The problem is rather severe because, on the one hand, there ifi the large ratio of one to seven hundred or more of fissile to fertile material that nature has endowed us with, and, on the other, the conversion of fertile material is less than unity in efficiency unless one goes to breeder reactors. Even at 0.9 reconversion claimed in some heavy water reactors, the total utilisation can in principle be increased from 0.792 of the uranium to about 7$ of the uranium over a long Bpan of time. However, even in breeder reactors the efficiency although greater than unity, 1B quite small ranging from 1.025 to 1.1 under the beet of design and other elements of construction. Taking the higher figure, the conversion rate is still low and does not 280 permit more than one new power reactor for every twenty for 50$ fuel burnout. This results in unviable programmes in the long range as the fertile material build up cannot be matched by its utilisation. There is a second problem in that breeding Involving fissile plutonlum 239 has greater disadvantages in neutron economy than the use of fissile U-235 and U233 because of the slightly smaller number of neutrons per fission. The trend, therefore, in almost all countries is not towards U-238 or Th-232 and Pu-239 breeding cycles but a proper mixture of Pu-239,tfr-233 in the breeding cycles so that the fullest use of the naturally occur - ing fertile materials is made. Che of the conoepte that interested Bhabha at one time was to investigate beryllium as a moderator far great- er neutron economy. We do not know hem far these experiments ware pursued but at that time they were certainly forward looking ideas* Normally If one has to depend on natural heavy water reactors far power and for producing Pu-239 the xatio of utilisation of fertile material to fissile material will be ultimately somewhere around 10t 1. In principle this could be extended to around 40:1 by UBing beryllium* In such a situation the compulsions of diminishing returns will weigh heavily on future, atoaie power programmes if we think in terns of Candu type reactors in the long time perspective. 4. While & viable programme of development of breeder reactors with Pu-239 should be studied* it should not preclude study of the long range economies of fertile and fissile material worked out for all combinations of usable fertile and fissile materials. If it appaars that enrichment giveB more viable reactors in the long range, one should examine possible breeder programmes with enriched uranium and other consequential progra- mmes that would be needed. While a programme of breeder reactors involves a viable and economic process of enrlohment to make the fullest use of the naturally occuring TJ-235, the enrichment requirements for breeding fortunately, are not as stringent as for weaponaryand therefore would be within the current policies of our government. 5. To me there are other challenging possibilities in the horlaon* Amongst these are high temperature reactors which will give much greater ,''•1 efficiency than the current 25% or so. This neceeaHrily would mean going in the direction of liquid metal coolants, ceramic technologies and direct conversion of the motion of the liquid metal coolant to electric, power by magneto-hydro-dynamic methods. These incorporated in the breeder reactors make a very tempting picture for the future of nuclear power. A number of challenges that take us nearer to this objective are quite clearly seen today. There are others which will surely appear as we go along this direction. The solution of the Be will require a very large amount cf developmental and research effort both in technology and In science.