ISO 18077:2018 pdf free

ISO 18077:2018 pdf free.Reload startup physics tests for pressurized water reactors
The important analysis characteristics that shall be confirmed by measurement are the following:
a) Reactivity balance: Reactivity balance neutronically demonstrates that the total amount of fuel loaded in the core is consistent with design. The boron end point measurements confirm that the amount of various fissionable materials in the core, as well as the reactivity effects of various fixed poisons (e.g. burnable absorbers) and transient poisons (e.g. samarium), is consistent with the design calculations.
b) Reactivity control: Reactivity control refers to the reactor core parameters that have an impact on the ability of the operators to control the plant. The primary parameter that confirms this is the isothermal temperature coefficient.
c) Power distribution: Power distribution is a measurement (check) that the core is loaded properly and will perform as designed. When the measured power distributions agree with predictions,there is high confidence that the as-built core and the designed core are the same. In addition,there is increased confidence that the conclusions of the safety analyses are correct. Finally, close agreement between measured and predicted power distributions increases the confidence that reactivity control parameters will perform as designed.
d) Capability to shutdown: Capability to shutdown is demonstrated by showing that the measured control rod worths are consistent with the calculated values. The shutdown margin calculations are based upon design values, which shall be confirmed.
e) Requirements to shutdown: The requirements to shutdown are the reactivity elements that the safety and regulating control rods shall overcome in a reactor trip. The shutdown margin calculations are based upon design values, which shall be confirmed.
Any new testing process or program of tests that are not described in Annex A shall specify how the above parameters are to be confirmed.
The reload startup testing program is constructed such that as the power ascension proceeds, the level of confidence in confirmed reactor characteristics continues to improve. Similarly, the results of testing at a given power level shall provide reasonable assurance that the next proposed power level can be achieved without risk of violating the design or licensing bases of the plant.ISO 18077 pdf download.