2001 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1955 



limited by the strength and size of the vessel in which the reactor 

 must be contained. One of the difficult problems in this reactor will 

 be that of getting control mechanisms to operate in a high-pressure 

 vessel. Principally, we hope to learn from this reactor how such a 

 plant may stand up under ordinary operating conditions of a central- 

 station electric powerplant and how much it costs to build and operate 

 it. We have no expectation that this reactor will produce power as 

 cheaply as a modern coal-burning plant, but we hope to learn how 

 costs can be cut in later plants. 



The second new reactor which we wish to build is a breeder of 

 intermediate size. It will not be of direct interest from the point 

 of view of economic power, but it will be much larger and much more 

 nearly a power-producing, continuously-operating reactor than the 

 small experiment we have been running out in Idaho. The scale-up 

 planned is from 1,400 to 62,500 kilowatts of heat, and from 170 to 

 15,000 kilowatts of electric power. Temperatures and steam pressure 

 will be increased to values appropriate to a full-scale power breeder 

 reactor. Auxiliaries such as pumps, heat exchangers, valves, etc., 

 will be of sizes suitable to a full-scale reactor. 



Our third step is based on the boiling experiment that I have 

 already described. It will be an attempt on an intermediate scale 

 actually to use boiling of the water as a method of heat extraction. 

 We hope in this way to get a very cheap method of getting the heat 

 out of the reactor and possibly of eliminating one step between the 

 coolant in the reactor and the turbines which turn the generator. It 

 is planned to feed the steam generated in the reactor directly to the 

 turbines. Present plans call for 20,000 kilowatts of heat and 5,000 

 kilowatts of electric power. 



The fourth reactor which we mtend to build is a larger version 

 of the homogeneous reactor. Again, it will be a step in the direction 

 of a practical power-producing unit and should give us information 

 about corrosion, chemical processing, and operating conditions that 

 cannot be obtained with the small machine now in use at Oak Ridge. 

 Present specifications call for only 3,000 kilowatts of heat in this re- 

 actor experiment compared to 1,000 in the present experiment. The 

 next step, already planned, calls for 65,000 kilowatts of heat in a 

 homogeneous reactor which will breed uranium 233 in a blanket of 

 thorium surrounding the chain reacting core. 



The fifth reactor experiment which we plan to build is a little dilffer- 

 ent from any that I have described. I have mentioned that the breeder 

 reactor uses sodium-potassium alloy as a coolant. The Hanford re- 

 actors use graphite as a moderator. We hope to be able to combine 

 these two materials, getting the advantage of high temperature with- 

 out high pressure from the sodium coolant. To test this combination, 



