April 9. Duke Energy outdoor warning sirens at McGuire Nuclear Station and Catawba Nuclear Station will be tested April 9, between 11 am ad 1 pm. These quarterly tests are part of normal maintenance to ensure the sirens are working properly. During this test, the sirens will sound for 5 to 30 seconds. Please note that it will not be a full-volume test, so some residents may not hear the sirens unless they are located close to one.