Can you use Trap Jammer to destroy Fusion Sword Murasame Blade as soon as it is played face-up in Yu-Gi-Oh?
No. "Trap Jammer" can only be used on Trap cards; "Fusion Sword Murasame Blade" is a Spell card. Plus, "Trap Jammer" can only be activated during the Battle Phase.
If you meant Magic Jammer, then yes. Fusion Sword Murasame Blade's protection effect is only applied after FSMB resolves initially, becoming active. So you can negate the activation and destroy it before that, or you can even chain Mystical Space Typhon, destroying it before it resolves, again before the protection effect becomes active.