Prompt critical, definition

Supercriticality definition of critical, prompt critical, reactivity, the inhour equation approximations to the inhour equation for long periods and very short periods reactivity units--preferred % , but mention pern, dollars and inhours, and conversion from one to another negative periods and limitations. 

By definition, an exactly critical reactor can be made prompt critical by adding positive reactivity equal to ... 

Wolfgang Pauli once stated that the surface was invented by the devil, illustrating the complexity and difficulty of studying the surfaces of materials. This prompts a fundamental question What is the surface of a material The simplest definition is that the surface is the boundary at which the atoms that make up one material terminate and interface with the atoms of a new material. If the surface is considered to be just the outermost layer of atoms of a material, then it comprises on average only 10 atoms per square centimeter (1 square centimeter equals 0.155 square inch), as compared to the bulk of the material, which consists of approximately 10 atoms per cubic centimeter. Surface chemistry is important in many critical chemical processes, such as enzymatic reactions at biological interfaces found in cell walls and membranes, in electronics at the surfaces and interfaces of microchips used in computers, and the heterogeneous catalysts found in the catalytic converter used for cleaning emissions in automobile exhausts. 

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