Providing of design condition for MK-III cooling system remodeling for JOYO. Establishment of the thermal transient condition for the structural design of equipment and piping. The final edition

The thermal transient conditions for the structural design are established in order to perform manufacture design of MK-III cooling system remodeling. The calculated data by MK-III version of the analysis code MIMIR-N2' are used for establishing. (Establishing Conditions of the thermal transient) (1) Calculation of ΔT and ΔT/t safety factor. The safety factors are calculated with the parameter safety factor and the thermal conditions safety factor of the same kind. 1) The parameter safety factor. The parameter safety factors are calculated to perform analysis by uncertainty range of plant parameter. 2) The thermal transient safety factor of the same kind. The thermal transient safety factor of the same kind are unified (2) Making of fold line figure 1) For each thermal transient, the fold line graph is drawn through the fiducially points which are the intersections of the datum temperature lines and the large temperature change rate lines and drawn in each part divided as the temperature range is less than 20degC at the large temperature change rate (more than 0.2degC/sec) range. And it is drawn in each part divided as the time range is less than 100sec at the little temperature change rate (less than 0.2 degC/sec) range. 2) Making of thermal transient condition are multiplied the safety factor on the calculated data. (3) Condition of the associate steady state. Temperature fluctuation usually abates within 2000-3600sec from the start of the transient, and thermal transient analysis is conducted for the time range. So the part of the fold time after the abatement of the temperature fluctuation is drawn as the temperature uniformly drops to 250degC at the rate of -50degC/h. The thermal transient conditions established above shall be used for the basic design of MK-III cooling system remodeling. (author)