During wp replacements it's wise to check the stainless steel cone in the wp housing to ensure it's not loose. Cavity behind cone first place to look for missing impeller bits, and a fill/run engine/drain/fill/run engine/drain cycle on cooling system after new pump installed a good idea before anti-freeze is installed.
Both my pumps went last May and I recovered 90% of the shattered impellers and followed the foregoing with no detrimental after effects.
If less than 90% of impeller recovered then 'stat housing might be first place to look before segmenting the cooling system to perform proper back flush procedures.
