190 ANNUAL REPORT SMITHSONIAN mSTITUTION, 1955 



contract to the Government and is now becoming more and more 

 active on its own initiative. This is as it should be. 



Those of us engaged in this effort believe we shall be successful. We 

 are so confident of success that we do not begrudge the years and the 

 skill and the millions of dollars that are being spent to make available 

 to man the kind of energy that heats the stars. But the road to suc- 

 cess will be a long one. We know that it will have many dead ends and 

 wrong turnings and many dull and dreary stretches. The barriers to 

 be surmounted or bypassed are formidable. 



By now we think we know what these barriers are, what kinds of 

 problems have to be solved if nuclear power is to be significant in our 

 economy. We should know these problems, for it is now 15 years since 

 nuclear fission was discovered, 10 years since the first large-scale 

 nuclear reactor was started, and 5 years since the Atomic Energy 

 Commission announced its first program of nuclear reactors aimed at 

 power. Energy from nuclear powerplants will be just like energy 

 from coal-burning powerplants. Except for special purposes, the 

 sole criterion of comparison will be cost. 



The problems of reactor development today are best explained in 

 terms of those which faced the designers of the first great reactors at 

 Hanford. They are so fundamental that they will continue to be of 

 major importance even though the emphasis may shift from time to 

 time. Once I have defined the problems, I shall outline our present 

 state of knowledge and the next major steps we are planning for their 

 solution. 



THE GENERAL PROBLEMS OF A NUCLEAR POWER REACTOR 



Let me recall to you the three major facts of nuclear fission : First, 

 that enormous amounts of energy are released ; second, that the prod- 

 ucts of fission are radioactive; and third, that fission is caused by 

 neutrons and results in the production of further neutrons, thereby 

 making a chain reaction possible. 



These basic facts confront the designers of reactors with a series of 

 technical questions which can be grouped in five general areas. These 

 general areas that have to be considered are, first of all, what we call 

 neutron economy; second, the effects of nuclear radiation; third, heat 

 transfer or removal ; fourth, control and instrumentation ; and fifth, 

 chemical processing of fuel both before and after it goes into the 

 reactor. Let me go into some detail about these five areas. 



NEUTRON ECONOMY 



It is evident that the first requirement of a nuclear reactor is that the 

 nuclear chain reaction shall occur. In other words, if a uranium 

 nucleus in a structure containing uraniimi does midergo fission, it must 



