As Chuck says below, you can't use the B21/23 "gear" (aka timing belt sprocket). And there is no removable crankshaft key.

The crank sprocket is keyed to the crankshaft with built-in key. The crankshaft "balancer" pulley has a slot on the back that keys it to the "nib" on the front of the crank sprocket. The nib is what's been sheared off. Probably due to an improperly torqued crank pulley bolt

The crankshaft sprocket's built-in shaft key and "nib" on front face can be seen below:


Here is the belt pulley/balancer showing the slot/recess on back face that keys to the "nib" on front face of crankshaft sprocket.


You probably don't need a new harmonic balancer, but will need the belt drive sprocket for a '93 or later B230, which uses the "round-toothed" timing belt.

Part # and Price from Tasca Volvo...

Item Number MSRP Core Price Price
9135271 $56.87 $0.00 $42.18 plus about $10 shipping
Crankshaft gear, all models - 2.3l, b230f/b230ft 1993 - 1994

You'll probably also need new rear "locating plate", the notched belt guide washer that fits behind the crank gear. PN 3531184 is $2.59 at Tasca.
The front locating plate is PN 1357621.

--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.