Patent Number: 051695928
Section: claims

1. In a method for protecting a nuclear reactor in the event of an increase in its load, said method comprising the steps of: (a) monitoring an operating temperature of said reactor;  (b) setting an emergency stop limit for nuclear power of said reactor;  (c) monitoring said nuclear power;  (d) comparing said monitored nuclear power to said emergency stop limit; and  (e) stopping said reactor when said monitored nuclear power exceeds said emergency stop limit;  (f) setting a reference temperature for said operating temperature;  (g) comparing said monitored operating temperature to said reference temperature; and  (h) lowering said emergency stop limit when said monitored operating temperature becomes less than said reference temperature.  a core (2) containing fuel rods in which a nuclear reaction takes place, giving off nuclear power which is spread between a top and a bottom of the core and which is transformed into heat;  a heat exchange circuit (4, 6, 8) for causing a heat exchange fluid to penetrate into the core via an inlet duct (4), for causing it to flow through the core, and for causing it to leave the core via an outlet duct (6), thereby removing said heat, said circuit delivering the heat to a heat receiver (10) having varying needs; and  control clusters (12) penetrating in controlled manner into said core in order to control said nuclear reaction; said method comprising the steps of:  the improvement wherein said method further comprises the steps of: 2. In a method for protecting a nuclear reactor in the event of an increase in its load, said reactor comprising: 3. A method according to claim 2, comprising the step of further using said function generator for further lowering said emergency stop limit when said operating temperature decreases from a value less than said reference temperature. 4. A method according to claim 2, comprising the step of further using said function generator for further lowering said emergency stop limit by a predetermined limit-lowering amount each time said operating temperature decreases by a predetermined value from a value less than said reference temperature. 5. A method according to claim 2, wherein said reference temperature (TR) lies in the range of 270.degree. C. to 320.degree. C. 6. A method according to claim 5, wherein said method is applied to a pressurized water reactor and said reference temperature (TR) lies in the range of 290.degree. C. to 300.degree. C. 7. A method according to claim 5, wherein said function generator gives to said emergency stop limit, when said operating temperature (ST) is 20.degree. C. less than said reference temperature (TR), a value which is less than one-half the value that said function generator gives to it when said operating temperature is close to but greater than said reference temperature.