Going back over reports on the No. 4 reactor and the spent fuel pool, I realized I had been seeing something that wasn't registering.

The sentence that woke me was this- CNIC* staff member Masako Sawai said, "....... one of those spent fuel-rod pools stores several times more nuclear fuel than that in a reactor core-....."
*CNIC- Citizens' Nuclear Information Center. [Based in Tokyo, "We work to create a nuclear free world". The link below is to their English language website. The quote is from Japan Times].

CNIC

The pools store not only spent fuel rods but fresh fuel rods; how many of each were in No. 4 pool, I haven't found out.