A revision of section 8 of TID-8516, Part I, is presented. The reactor concept which is presented is a change from the former design, a pressurized- pressure vessel-indirect cycle plant to a boiling-pressure tubedirect cycle plant. A description of the plant and a summary of characteristics for the 110- and 325- Mwe systems are given. (J.R.D.)

The reactor design which forms the base for the current economic status of D/sub 2/O-moderated reactors was estimated from developments in several reactor programs. However, since a heavy water-moderated reactor was not operated on natural U fuel at power reactor conditions, considerable improvement from this current status can be foreseen. A summary of improvements is presented concerning the concept which would result solely from operation of succeeding generation plants without a parallel development program, and improvements which would result from the successful completion of the development program as presented. One plant size was used in the evaluation of plant potential, with a 300 Mw/sub e/ nominal rating. The boiling D/sub 2/O-cooled, pressure tube direct cycle plant design was used. The current development program is outlined; this work includes several items leading to the long-range development of the concept. (auth)

An evaluation of 300- and 100-Mwe power plants was conducted using ground rules prescribed by the USAEC for this study. Costs corresponding to two average discharged fuel burnups are: 8.6 mills/kwh (8500 Mwd/ metric ton) and 8.8 mills/kwh (7500 Mwd/metric ton) for the 300-Mw plant. Costs for the 100 Mw plant are 14.7 mills/kwh for an average discharged fuel burnup of 6010 Mwd/metric ton. Estimates of future potential indicate that the 300 Mw/sub 3/ (8500 Mwd/metric ton) plant could produce power for 7.3 mills/kwh in a second generation, full scale plant of the same type. A further reduction to 6.4 mills/kwh should be possible as the result of the recommended ten-year development program. The current development program is adequate for providing the data needed to design and construct a prototype reactor. However, there is no natural U-fueled prototype and no prototype of the chosen reference design scheduled in the U.S. Current technology is sufficiently developed to initiate the design and construction of a pressure tube, boiling D/sub 2/Ocooled, natural UO/sub 2/- fueled reactor prototype plant in the immediate future. This plant would demonstrate the main features of a full scale plant and, in addition. would provide design data which could …