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The heating value (or energy value or calorific value) of a substance, usually a fuel or food (see food energy), is the amount of heat released during the combustion of a specified amount of it. The calorific value is the total energy released as heat when a substance undergoes complete combustion with oxygen under standard conditions.
In nuclear power technology, burnup is a measure of how much energy is extracted from a given amount of nuclear fuel. [1] It may be measured as the fraction of fuel atoms that underwent fission in %FIMA (fissions per initial heavy metal atom) [2] or %FIFA (fissions per initial fissile atom) [3] as well as the actual energy released per mass of initial fuel in gigawatt-days/metric ton of heavy ...
MOX fuel is an alternative to low enriched uranium (LEU) fuel used in the light water reactors which predominate nuclear power generation. Some concern has been expressed that used MOX cores will introduce new disposal challenges, though MOX is a means to dispose of surplus plutonium by transmutation .
Fuel temperature coefficient of reactivity is the change in reactivity of the nuclear fuel per degree change in the fuel temperature. The coefficient quantifies the amount of neutrons that the nuclear fuel (such as uranium-238 ) absorbs from the fission process as the fuel temperature increases.
For instance, the use of MOX fuel (239 Pu in a 238 U matrix) is likely to lead to the production of more 241 Am and heavier nuclides than a uranium/thorium based fuel (233 U in a 232 Th matrix). For highly enriched fuels used in marine reactors and research reactors , the isotope inventory will vary based on in-core fuel management and reactor ...
For unoxidized fuel 2300 K was required to release 10% of the uranium while oxidized fuel only requires 1700 K to release 10% of the uranium. According to the report on Chernobyl used in the above table 3.5% of the following isotopes in the core were released 239 Np, 238 Pu, 239 Pu, 240 Pu, 241 Pu and 242 Cm.
To express the efficiency of a generator or power plant as a percentage, invert the value if dimensionless notation or same unit are used. For example: A heat rate value of 5 gives an efficiency factor of 20%. A heat rate value of 2 kWh/kWh gives an efficiency factor of 50%. A heat rate value of 4 MJ/MJ gives an efficiency factor of 25%.
The fuel is mixed with heavy or light water which partially moderates and cools the reactor. The outside layer of the reactor has more water which also partially cools and acts as a moderator. The water can be either heavy water or ordinary (light) water, which slows neutrons and helps facilitate a stable reaction, both of which need to be very ...