1. Cook pasta according to package directions; drain. Rinse with cold water; drain again.
2. Meanwhile, for dressing, stir together mayonnaise, vinegar, mustard, sugar, and celery seed; set aside.
3. In a large bowl combine pasta, broccoli, kidney beans, and green onions. Pour dressing over pasta mixture; toss gently to coat. Stir in orange sections. Serve immediately or cover and chill for several hours.