Despite the belief in their inherently safe design, it was decided that the Magnox stations would not be built in heavily populated areas. The positioning constraint decided upon was that any 10-degree sector would have a population less than 500 within 1.5 miles, 10,000 within 5 miles and 100,000 within 10 miles. In addition population around the site in all directions would be less than six times the 10-degree limits. Planning permission constraints would be used to prevent any large growth of population within five miles.