MTC Calculation

Could anyone help me saying how to calculate MTC using openmc?

I have made a scheme to perform my stuffs but my graphs show like MTS, not MTC. I have defined materials and then in moderator definition fixed temperature 574k and collect the data of keff eigen value in respect EFPDs, and then same is done for 594k. And from this two data i have calculated MTC.

Is this a wrong process ? Or what should i change in the process?

Please give me a solution, i will be grateful to you.