ML19191A251
| ML19191A251 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 07/10/2019 |
| From: | Ed Miller Special Projects and Process Branch |
| To: | Aitken D, Sly C Dominion Energy Co |
| References | |
| Download: ML19191A251 (5) | |
Text
Code of Federal Regulations
Please provide a mark-up of North Anna Technical Requirements Manual showing how the time delays will be incorporated and explain how any future changes in time delay settings will be controlled.
Please address how you will resolve these discrepancies. If UFSAR changes are needed to make the UFSAR consistent with the LAR, provide any corresponding UFSAR revision markups. Please provide the following additional information:
(a) A brief calculation showing how the above fault impedance of 173.4 ohms was obtained. (b) Confirmation that doubling the fault impedance is considered more conservative. (c) How the above various types of ground connections were considered in the Table-1 provided on Page 15 of LAR, Attachment 1, and explain the significance of "Time = 8 seconds" provided in Table-1.
Because no alarm is provided in the control room if the voltage unbalance is between 1% and 5%, please provide a tabulation of all study cases in which the voltage unbalance is between 1% and 5%, and justification why all these cases are considered acceptable without any alarm or tripping function.