Heat 2 tablespoons oil in a large heavy based pot over medium high heat. then add the shrimp. Sauté until shrimp begin to turn pink, about 2 minutes. Add remaining 1/2 cup wine. Simmer until shrimp are just cooked through, about 2 minutes. Drain shrimp.

Heat oil in heavy large saucepan over medium heat. Add chopped onion and sauté until tender, about 5 minutes. Add minced garlic and stir 1 minute. Add rice, celery and stir until edge of rice is translucent but center is still opaque, about 2-3 minutes. Add wine and cook until wine is absorbed, stirring occasionally, about 2 minutes. Add 3/4 cup chicken broth. Simmer until almost all broth is absorbed, stirring often, about 2 minutes. Continue to add broth, 3/4 cup at a time, until rice is just tender and mixture is creamy, stirring often and allowing almost all broth to be absorbed after each addition, about 20-25 minutes total.

Stir shrimp and 2 tablespoons parsley into risotto. Season risotto to taste with salt and pepper. Transfer to bowls.