ML14183A783
| ML14183A783 | |
| Person / Time | |
|---|---|
| Site: | Robinson  |
| Issue date: | 02/14/1997 |
| From: | Mozafari B Office of Nuclear Reactor Regulation |
| To: | Hinnant C Carolina Power & Light Co |
| References | |
| TAC-M97957 NUDOCS 9702240287 | |
| Download: ML14183A783 (4) | |
Text
February 14, 1997@
Mr. C. S. Hinnant, Vice President Carolina Power & Light Company H. B. Robinson Steam Electric Plant, Unit No. 2 3581 West Entrance Road Hartsville, South Carolina 29550
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION REGARDING THE ADEQUACY OF DELAYED OFFSITE POWER CIRCUIT FOR THE H. B. ROBINSON STEAM ELECTRIC PLANT, UNIT NO. 2 (TAC M97957)
Dear Mr. Hinnant:
The NRC has recently reviewed offsite power system designs for older operating plants as a result of lessons learned from the Maine Yankee Independent Safety Assessment. The review was conducted to verify the adequacy of delayed offsite power circuits. In particular, the staff was concerned with plants that rely upon main and unit auxiliary transformers to backfeed power to the onsite distribution system by removing the disconnect links between the main generator and the main transformer.
Before we can conclude that the offsite power system design at the H. B. Robinson Steam Electric Plant, Unit No. 2 (HBR) meets its design licensing basis, additional information is needed regarding the delayed offsite power circuit at HBR. The response to the enclosed request for additional information is expected within 30 days.
Please contact me at (301) 415-2020 if you have any questions concerning this request.
Sincerely, s /
Brenda Mozafari, Project Manager Project Directorate II-1 Division of Reactor Projects -
I/II Office of Nuclear Reactor Regulation Docket No. 50-261 Distribution:
Docket File OGC
Enclosure:
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Mr. C. S. Hinnant H. B. Robinson Steam Electric Carolina Power & Light Company Plant, Unit No. 2 cc:
Mr. William D. Johnson Mr. Dayne H. Brown, Director Vice President and Senior Counsel Department of Environmental, Carolina Power & Light Company Health and Natural Resources Post Office Box 1551 Division of Radiation Protection Raleigh, North Carolina 27602 Post Office Box 27687 Raleigh, North Carolina 27611-7687 Ms. Karen E. Long Assistant Attorney General Mr. Robert P. Gruber State of North Carolina Executive Director Post Office Box 629 Public Staff - NCUC Raleigh, North Carolina 27602 Post Office Box 29520 Raleigh, North Carolina 27626-0520 U.S. Nuclear Regulatory Commission Resident Inspector's Office Mr. Max Batavia, Chief H. B. Robinson Steam Electric Plant South Carolina Department of Health 2112 Old Camden Road Bureau of Radiological Health Hartsville, South Carolina 29550 and Environmental Control 2600 Bull Street Regional Administrator, Region II Columbia, South Carolina 29201 U.S. Nuclear Regulatory Commission 101 Marietta St., N.W., Ste. 2900 Mr. J. Cowan Atlanta, Georgia 30323 Vice President Nuclear Services and Environmental Mr. Dale E. Young Support Department Plant General Manager Carolina Power & Light Company Carol-ina-Power-&-Light-Company --
Post Off ice Box T551 - Mail OHS7 H. B. Robinson Steam Electric Plant Raleigh, North Carolina 27602 Unit No. 2 3581 West Entrance Road Hartsville, South Carolina 29550 Mr. Milton Shymlock U. S. Nuclear Regulatory Commission Public Service Commission 101 Marietta Street, N.W. Suite 2900 State of South Carolina Atlanta, Ga. 3023-0199 Post Office Drawer 11649 Columbia, South Carolina 29211
REQUEST FOR ADDITIONAL INFORMATION REGARDING THE ADEQUACY OF THE DELAYED OFFSITE POWER CIRCUIT FOR THE H. B. ROBINSON STEAM ELECTIC PLANT, UNIT NO. 2 The NRC recently performed a review of offsite power system designs for older operating plants as a result of lessons learned from the Maine Yankee Independent Safety Assessment. The review was conducted to verify the adequacy of delayed offsite power circuits. In particular, the staff was concerned with plants that rely upon main and unit auxiliary transformers to backfeed power to the onsite distribution system by removing the disconnect links between the main generator and the main transformer. This review noted this feature in the design of the H. B. Robinson Steam Electric Plant, Unit No. 2 (HBR).
HBR was licensed with only one immediately available offsite power circuit and a delayed offsite power circuit that relies on a backfeed through the main and unit auxiliary transformers. To establish this backfeed the main generator disconnect links must be removed. For a delayed offsite power circuit to be considered an acceptable source of offsite power, it must be shown that power can be reestablished in sufficient time to prevent fuel design limits and design conditions of the reactor coolant pressure boundary from being exceeded. The HBR Updated Final Safety Analysis Report (UFSAR) states that removal of the main generator disconnect links in order to establish offsite power is expected to take a minimum of four hours. The UFSAR does not state, however, the maximum expected time needed to establish this backfeed source of power. The staff could not find any documentation to indicate that an analysis has been done to demonstrate the adequacy of this delayed offsite power circuit.
The staff is concerned that Carolina Power & Light Company (CP&L) may not have performed an analysis to demonstrate the adequacy of its delayed offsite power circuit. To resolve this concern, we request that you provide the information requested below.
- 1.
State whether you have performed an analysis to demonstrate that the delayed offsite power circuit can be established in sufficient time to prevent fuel design limits and design conditions of the reactor coolant pressure boundary from being exceeded. If such analysis was performed, provide a summary of the analysis and any conclusions (e.-g., adequacy of time limits and voltages, etc.).
ENCLOSURE
-2
- 2.
Describe any procedures in place for implementing the delayed offsite power circuit when needed, and state whether CP&L has tested its capability to backfeed power within an allowable time limit. If so, state how often operators are trained on using the procedures and how long it takes to establish the backfeed.
- 3.
The staff noted that HBR's Technical Specifications do not contain surveillance requirements regarding the delayed offsite power circuit.
Explain how HBR periodically verifies its ability to establish offsite power within a specified time limit using the main and unit auxiliary transformers.