Step 1Cook the celery, onion and carrot in the olive oil in a skillet over medium-high heat until transparent, about 5 minutes. Add the garlic and cook until fragrant, about 1 minute. Add the wine and simmer 1 to 2 minutes. Stir in the tomatoes and the chicken stock. Add the saffron, orange zest, pepper flakes, salt, olives and capers. Reduce the heat to medium and continue to simmer while preparing the scallops.
Step 2Heat the vegetable oil in a large skillet over high heat. If the scallops are very moist, pat them dry with paper towels. Add to the skillet and sear about 2 to 3 minutes on each side. Do not try to move the scallops until they release easily. The scallops should be golden brown on the outside but still tender inside.
Step 3Divide the broth among 4 large shallow soup bowls. Place 3 scallops in the middle of each bowl.