Method of dynamic control rod reactivity measurement

A method of dynamic control rod reactivity measurement for a reactor using a fission chamber as an out-of-reactor measuring instrument, the method comprising:

• maintaining, for a first period of time, the reactor in a critical state having a set output by inserting a reference control bank into a reactor core to a first depth;
• completely inserting the reference control bank into the reactor core from the first depth at a first maximum allowable speed and immediately completely withdrawing the reference control bank from the reactor core at the first maximum allowable speed, and measuring a first signal of the out-of-reactor measuring instrument from before the complete insertion of the reference control bank to after the withdrawal of the reference control bank;
• maintaining, for a second period of time, the reactor in the critical state having the set output by inserting a test control bank into the reactor core to a second depth;
• determining a residual reactivity measurement value, wherein the residual reactivity measurement value is a difference between a first dynamic reactivity of the reactor core when the reference control bank is completely withdrawn from the reactor core and a second dynamic reactivity of the reactor core when the test control bank is inserted to the second depth;
• and
• determining a static reactivity of the reference control bank by adding the residual reactivity measurement value to a first static reactivity of the reactor, wherein the first static reactivity is calculated using the first signal of the out-of-reactor measuring instrument.