Method and apparatus for load following with a single-cycle boiling moderator-coolant nuclear reactor

In a power plant of the type wherein a turbine is driven by a primary flow of steam at a predetermined pressure from a single-cycle boiling moderator-coolant nuclear reactor, said reactor including means to vary moderator-coolant recirculation flow to vary reactor power, and said power plant including a secondary flow of steam for heating steam utilizing auxiliary plant equipment, a load following system comprising:

• a turbine governor responsive to changing demands for turbine power;
• a primary steam control valve responsive to said governor for adjusting said primary flow of steam in response to said changing demands for turbine power;
• recirculation flow control means responsive to said governor for adjusting said moderator-coolant recirculation flow through said reactor in response to said changing demands for turbine power;
• a pressure regulator for monitoring the pressure of said primary flow of steam at a point upstream of said primary steam control valve;
• and
• secondary flow control means responsive to said pressure regulator for
• (i) reducing said secondary flow of steam, in the case of a rapid increase in turbine demand that causes a decrease in the pressure of the primary flow of steam, thereby maintaining said pressure and preventing a decrease in turbine power, and
• (ii) restoring said secondary flow of steam after adjustment of said moderator-coolant recirculation flow has increase reactor power and increased the pressure of said primary flow of steam.