JOYO MK-III Performance Test Report; Thermal Power Calibration (PT-311)

Oyama, Kazuhiro; Kawahara, Hirotaka ; Ariyoshi, Masahiko; Sugaya, Kazushi*; Fukami, Akihiro*

In the MK-III performance test, the experimental fast reactor JOYO measured the reactor thermal power in each step from a low power to a full power, and calibrated the intermediate range neutron monitors and power range neutron monitors of core instrumentation equipment. This report summarized the result of thermal power calibration.The outline is as follows. (1) We measured the reactor thermal power in each step from a low power to a full power, and calibrated the intermediate range neutron monitors and power range neutron monitors of core instrumentation equipment. Between the power range neutron monitors and the reactor thermal power, it has confirmed from this that there was good linearity. (2) From transition of November 20 [November 14 to] reactor thermal power, and the graphite temperature, although the graphite temperature (83-5,6,7) is rising to about 97 degree, it is mostly saturated in the 6th day after the full power attainment. In addition, thermal power calibration was carried out 4 times within this period. (November 14th, 15th, 16th, 18th) (3) All the errors of the full power measurement at the time of rating are 3.42% (=4.8 MWt). It is in the reactor thermal power error used by the thermal design of a MK-III reactor core (3.6%). (4) The compensation coefficient in