In a very large heavy pot or Dutch oven, brown ground beef. Add onion, celery, green pepper, salt and pepper. Cook, stirring often, until vegetables are softened. Drain off any excess fat. Add tomatoes, tomato juice, kidney beans, mushrooms and chili powder. Bring to boil; stir in noodles. Reduce heat, cover and simmer for about 15 minutes or until noodles are tender. Taste and adjust seasoning if necessary. Makes about 8 servings.