Patent GB-1229943-A (GB)
IPC: G21D5/06
Filed: 1968-08-26
Abstract: 1,229,943. 943. Gas turbine plant - closed cycle type. SIEMENS A. G. Aug. 26, 1968 [Aug. 26, 1967] , No. 40782/68. Heading FIG. [Also in Division G6] The invention relates to a gas turbine installation for converting heat from a heat source into mechanical energy having a fluid circuit which includes the heat source and a compressorturbine set, the installation being operable in a normal mode with gaseous fluid under such conditions that it is substantially incompressible. there being means whereby the installation can be changed over to a further mode for emergency cooling or after-cooling of the heat source, the compressor then being arranged to provide a substantially increased volumetric rate of flow of the gaseous fluid at such a reduced pressure that it behaves substantially as an ideal gas, the afterheat from the heat source after it has been shut down being utilized to drive the compressor-turbine set in said further mode. The invention is described with reference to a plant in which the heat source is a nuclear reactor R and the working fluid is CO 2 . The working fluid discharging from the reactor passes through the heat exchanger W, then through a cooler K, the pressures and temperatures being as indicated on the Fig. The C0 2  then divides into two streams one passing to a compressor D 1 , then through the heat exchanger W where it is heated by the heated C0 2  discharging from the reactor, the C0 2  under high-pressure then passing in part to a turbine T 1  which drives the compressor D 1  which drives the compressor D 1 , and in part to a high-pressure useful power turbine T 5 , the valve A 3  being open during this phase of operation. After expansion in the turbine T 5  the Co 2  passes back through valve A 8  to the reactor R. The C0 2  after expansion in the turbine T 1  passes to the low-pressure power turbine T 3 , the valve A 1 being closed, the C0 2  after expansion in the turbine T 3  passing back to the reactor R together with the C0 2  from turbine T 5 . The second stream of C0 2  for the cooler K passes through a similar circuit comprising compressor D 2 , turbines T 5 , T 2 , T 4 , the valve A 4  being open and valve A 2  being closed during this phase of operation. The compressors D 1 , D 2  may be driven from the power turbine assembly T 5 , T 3 , T 4  by means of over-running clutches indicated at UK. Starting motors M 1 , M 2  are provided for the compressors D 1 , D 2 . In the event of failure of one of the C0 2  lines, the pressure in the circuit becomes reduced as indicated in Fig. 2 and the reactor R is shut down but the flow of cooling fluid through the reactor R must be maintained. The C0 2  from the reactor passes through the heat exhanger W and cooler K as before, then through compressor D 1 , heat exchanger W, turbine T 1  and thence back to the reactor. The valve A 3 is closed so that no C0 2  passes to the high-pressure power turbine T 5  and the valve A 1  is open so that C0 2  after expansion in the compressor drive turbine T 1  passes directly back to the reactor R without passing through the low-pressure power turbine T 3 . Similarly the second stream of CO 2  from the cooler K passes to the compressor D 2 , heat exchanger W and compressor-drive turbine T 2  and then directly back to the reactor R. A similar mode of operation is adopted in the event of normal shut-down of the plant so as to remove residual heat in the reactor. The turbines T 1 , T 2  may be arranged to drive the compressors D 1 , D 2  respectively only in the emergency or residual cooling modes of operation, the compressor D 1 , D 2  being driven in normal operation from the power turbine assembly through the clutches UK.