CHAPTER 7 DESIGN AND CONSTRUCTION OF EXPERIMENTAL HOMOGENEOUS REACTORS* 7-1 .
INTRODUCTION
7-1 .1 Need for reactor construction experience . The power reactor development program in the United States is characterized by the construction of a series of experimental reactors which, it is hoped, will lead for each reactor type to an economical full-scale power plant . Outstanding examples of this approach are afforded by the pressurized water reactor and boiling water reactor systems . The development of pressurized water reactors started with the Materials Testing Reactor, followed in turn by the Submarine Thermal Reactor (Mark I), the -Nautilus Reactor (Mark II), and the Army Package Power Reactor . Experience obtained from the construction of these reactors was applied to the full-scale plants built by the Westinghouse Electric Company (Shippingport and Yankee Atomic Electric Plants) and Babcock & Wilcox Company (Consolidated Edison Plant) . Although many have argued that the shortest route to economic power will be achieved by eliminating the intermediate-scale plants, most experts believe that eliminating these plants would be more costly in the long run . To quote from a speech by Dr . A . M . Weinberg [1], while discussing largescale reactor projects : "The reactor experiment a relatively small-scale reactor embodying some, but not all, the essential features of a full-scale reactor has become an accepted developmental device for reactor technology ." An alternative to the actual construction of experimental nuclear reactors has been proposed which consists of the development of reactor systems and components in nonnuclear engineering test facilities, zero-power critical experiments, and the testing of fuel elements and coolants in in-pile loops . This approach, although used successfully in the development of various solid-fuel coolant systems, is not completely applicable to circulating-fuel reactors because of the difficulty of simulating actual reactor operating conditions in such experiments . In in-pile loops, for example, the ratio of the volume of the piping system to the volume of the reacting zone is never quite the same as in a reactor, making it impossible to duplicate simultaneously the conditions of fuel concentration, enrichment, and power density . In cases where these variables are important, the in-pile loops *Prepared by J. A. Lane, with contributions from S . E . Beall, S . I . Kaplan, Oak Ridge National Laboratory, and D . B. Hall, Los Alamos Scientific Laboratory . 340