Nuclear reactor system and method for automatically scramming the same

An automatically scramming nuclear reactor system, comprising:

• a core;
• an electrically-resistive element positioned in thermal contact with said core, said electrically-resistive element having a variable resistance that changes with a change in temperature;
• a voltage source;
• a control element, said control element being moveable with respect to said core between an upper position and a lower position;
• and
• an electromagnet positioned adjacent said core, said electromagnet being electrically connected in series with said electrically-resistive element and said voltage source, said electromagnet holding said control element in the upper position during a normal operating condition of said reactor, said electromagnet releasing said control element when a temperature of said core changes from a safe operating temperature, said control element automatically falling under the action of gravity to the lower position when released by said electromagnet.

A method for scramming a nuclear reactor system, comprising:

• placing an electrically-resistive element in thermal contact with a core of said nuclear reactor system, said electrically-resistive element having a variable resistance that changes in response to a change in temperature of the core;
• connecting an electromagnet in series with said electrically-resistive element and a voltage source;
• and
• engaging a control element with the electromagnet, said control element being moveable with respect to the core between an upper position and a lower position, the electromagnet holding said control element in the upper position during a normal operating condition of said reactor, said electromagnet releasing said control element when a temperature of said core changes from a safe operating temperature, said control element automatically falling under the action of gravity to the lower position when released by said electromagnet.

An automatically scramming nuclear reactor system, comprising:

• a core;
• control means for scramming said core when said control means is lowered into said core;
• a voltage source;
• electrical-resistance means provided in thermal contact with said core for providing a variable resistance that changes with a change in temperature;
• and
• release means positioned adjacent said core, said release means electrically connected in series with said voltage source and said electrical-resistance means for releasing said control means when a temperature of said core changes from a safe operating temperature, said control means automatically falling under the action of gravity when released by said release means.

An automatically scramming nuclear reactor system, comprising:

• a core;
• a control element movable relative to said core between an upper position and a lower position;
• a voltage source having a first terminal and a second terminal;
• an electrically-resistive element having a first lead and a second lead, the first lead being connected to the first terminal of said voltage source, said electrically-resistive element positioned in thermal contact with said core and producing a variable resistance in response to an increase in a temperature of said core;
• a release system having a first terminal and a second terminal, the first terminal of said release system being connected to the second lead of said electrically-resistive element, the second terminal of said release system being connected to the second terminal of said voltage source, said release system being positioned adjacent said core, said voltage source providing an electrical current to said release system to hold said control element in the upper position during a normal operating condition of said nuclear reactor system, said electrically-resistive element reducing the electrical current to said release system when the temperature of said core exceeds a safe operating temperature so that said release system automatically releases said control element to fall under the action of gravity to the lower position.