This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
殩 combines 歹 (death/bones) with 粲, which likely contributes the sound. The exact historical development is uncertain.
The left side 歹 suggests death or remains, while the right side 粲 looks like a complex arrangement of 米 and other parts. Without a clear meaning, picture scattered bones and rice as a vague image of something broken or scattered.
For サン, imagine the sun (サン) shining on a pile of bones and rice, highlighting the scattered remains.