Heat the olive oil in a 7-liter pressure cooker over medium-high heat. Add the onion, garlic, fennel seeds, the 1 teaspoon salt, and pepper to taste. Cook, stirring occasionally, until the vegetables soften a bit, about 5 minutes. Add the rice, tomato paste, and saffron and stir until the grains are evenly colored. Stir in vermouth and chicken broth.

Close the pressure cooker lid and bring the pressure up to high (which can take up to 10 minutes), then reduce the heat, if necessary, to maintain an even pressure for 3 minutes. Remove from the heat and press the cooker's pressure indicator stem until no more steam comes out.

Carefully remove the lid--the risotto will look a bit soupy at this point. Stir in the shrimp and let the risotto stand, off the heat, until shrimp are pale pink and cooked through, about 2 minutes. Season with additional salt and pepper, to taste.