How to use shrinking particle model?

I defined two monitors, one for maximum reaction rate (MAXRATE), one for minimum particle radius (MINRAD)

MAXRATE.csv

# Monitor type: Maximum over region, Volume =   0.13959536E-02
# "Time","RRates_R2" 
    0.0000000    ,    0.0000000    
   0.99940518E-03,   0.10405285E-10
   0.20192453E-02,   0.22211349E-10
   0.30142453E-02,   0.12555630E-10
   0.40342453E-02,   0.18668314E-10
   0.50292453E-02,   0.23711911E-10

MINRAD.csv:

# Monitor type: Minimum over region, Volume =   0.13959536E-02
# "Time","r_p" 
    0.0000000    ,   0.10000000E-02
   0.99940518E-03,   0.10000000E-02
   0.20192453E-02,   0.10000000E-02
   0.30142453E-02,   0.10000000E-02
   0.40342453E-02,   0.99999999E-03
   0.50292453E-02,   0.99999999E-03

As can be seen, the particle radius does decrease.

Here’s the project file with the monitor definitions:
OCAC CH4.mfx (21.2 KB)