FAST-REACTOR DESIGNS IN THE USA - CHANGING GOALS AND OPTIONS

Liquid metal fast reactor developments in the USA have narrowed to two basic goals: (1) nominally inherently safe modular designs with passi ve cooling capability and minimum requirements for safety-grade equipm ent; and (2) an integrated fuel cycle based on pyroprocessing and meta l alloy fuel material. The current goals reflect basic departures from the originally conceived incentives and design goals for reactors cap able of high neutron efficiencies. The economic, logistic, and institu tional changes in the applicable factors that drive the changing goals are reviewed. The paper describes the current technical status and po ssible strategies for reaching a prototype stage during the next few d ecades. The key technical developments that appear to make the current goals attractive and feasible are surveyed. Prototypes have operated for several dozen reactor years and have experienced numerous non-nucl ear incidents. None of these events appear to pose significant obstacl es to the attainment of the safe and reliable operation of fast reacto rs. The historical developments leading to the current-status are summ arized in four periods from 1948 to 1993. The main factors discussed i nclude the dramatic changes in the size and dynamics of plutonium and uranium supplies, the improved picture on fossil fuel supplies, and th e resulting decline in the near-term cost competitiveness of nuclear: options in the USA. The dominant role of public perceptions and the so urces of misperceptions are discussed. The effects of federal regulati ons and litigation have also been very important. The combination of t hese changing circumstances serve to defer for several decades the pot ential for realizing the economic value of excess breeding gain. Never theless, a path of economically driven near-term nd long-term developm ent and deployment is foreseen. The promising near-term path involves the use of modular fast spectrum burner reactors that offer good prosp ects of achieving good economics near-term. These can also provide vit al national security benefits by using their capability for sequesteri ng plutonium from decommissioned nuclear weapons safely. (C) 1998 Else vier Science Ltd. All rights reserved.