In a large saucepan cook shrimp in boiling water about 3 minutes or until shrimp turn opaque; drain. Rinse shrimp under cold water; drain well.
Drain pineapple chunks, reserving juice. Combine pineapple chunks and orange sections; cover and chill.
For marinade, in a medium bowl combine 1/4 cup of the reserved pineapple juice, the mint, salt, and pepper. Stir in cooked shrimp and the celery. Cover and marinate in the refrigerator for 2 hours. Drain off marinade; discard marinade.
Stir pineapple chunks and orange sections into shrimp mixture.
In a small bowl combine 2 tablespoons of the remaining pineapple juice and the yogurt. Toss with the shrimp mixture. Divide mixture among 4 small airtight containers. Chill overnight or store up to 2 days in the refrigerator. Makes 4 servings.