Binary Plant Cycle Studies for the Gas Turbine HTGR

Abstract

The Gas Turbine High-Temperature Gas Cooled Reactor (GT-HTGR) employs a power cycle that commences waste heat rejection at relatively high temperature, thus making the use of dry cooling economically attractive. This heat can also be utilized by a low temperature secondary cycle that generates additional power at no increase in fuel cost. A supercritical Rankine cycle employing ammonia as the working fluid meets the requirements for the secondary power cycle. To achieve best overall performance for the combined binary cycle the helium recuperator, and precooler proposed for the dry-cooled GT-HTGR will require modification. Ammonia desuperheats upon expansion through a turbine, and care must be exercised to select cycle conditions that do not result in moisture formation or excessive superheat in the secondary power turbine exhaust. The combined plant output is sensitive to heat sink conditions, and for once-through cooling a 3000-MW(t) binary cycle GT-HTGR produces a net output of 1378 MW(e), which corresponds to an efficiency of 45.9 percent. For evaporative cooling, the output and efficiency are 1353 MW(e) and 45.1 percent, respectively. The heat-rejection system accounts for a large portion of the secondary plant cost, and requires careful optimization while accounting for the effects on plant performance.

The Closed-Cycle Turbine: Present and Future Prospectives for Fossil and Nuclear Heat Sources

“…System studies and equipment conceptual designs were done for an advanced version of the GT-HTGR _plant in an effort to evaluate the economic and performance potential (64,65). In its simplest form, the secondary power cycle would entail only the substitution of a vaporizable liquid for water normally in the precooler heat rejection loop (associated with an external vapor turbine, pump, and condenser) as shown on the cycle diagram in Fig.…”

Assessment of research and development (R and D) needs in ammonia safety and environmental control

“…Certain hydrocarbons and fluorocarbons have also been considered, but in most cases the NH 3 appears to be superior (Schuster, Vrable and Huntsinger 1976). Compared with the other possible choices, ammonia permits a supercritical cycle operation with good thermal efficiency; it has particularly good thermophysical properties for binary cycle applications and thus allows for substantially reducing the size of the binary cycle turbine and condenser.…”

Thermal and flow design of helium-cooled reactors

“…Table 2-III gives basic design data for three designsthe 3000-MW(t) U.S. HTGR (Ref. 57), the 2700-MW(t) Gennan pebble bed reactor, and the 3430-MW(t) low-enriched HTR of the United Kingdom. A great deal of similarity can be seen in helium conditions (temperature and pressure), type of fuel particles and bumup (coated oxide kemels with 85 to 100 MWd/kg bumup), power density (~8 MW/m^), cycle efficiency (37 to 39%), and also PCRV design and multicavity vessels with wire-winding and ceramic-type thermal insulation.…”