Anyone have the following newer SDM definition in their TS?

“SDM shall be the instantaneous amount of reactivity by which

the reactor is subcritical or would be subcritical from its

present condition assuming:

a. All rod cluster control assemblies (RCCAs) are fully

inserted except for the single RCCA of highest reactivity

worth, which is assumed to be fully withdrawn. However,

with all RCCAs verified fully inserted by two independent

means, it is not necessary to account for a stuck RCCA in

the SDM calculation. With any RCCA not capable of

being fully inserted, the reactivity worth of the RCCA must

be accounted for in the determination of SDM, and

b. In MODES 1 and 2, the fuel and moderator temperatures

are changed to the nominal zero power design level.”

If you have implemented this in your procedures what “two independent means” do you use after a trip to verify all rods have inserted?

In this SDM definition it seems the “Stuck RCCA” is used interchangably with the “single RCCA of highest reactivity worth, which is assumed to be fully withdrawn”.

I would read this as meaning the calculation if being performed after a trip and verifying all rods inserted would no longer have to include the single RCCA of highest reactivity worth.

Any thoughts?

Thanks

Ken Pike

(610) 277-8991 x 253