ML14183A745
| ML14183A745 | |
| Person / Time | |
|---|---|
| Site: | Robinson  |
| Issue date: | 07/03/1996 |
| From: | Mozafari B NRC (Affiliation Not Assigned) |
| To: | Hinnant C CAROLINA POWER & LIGHT CO. |
| References | |
| GL-95-07, GL-95-7, TAC-M93512, NUDOCS 9607100215 | |
| Download: ML14183A745 (5) | |
Text
July 3, 1996 Mr. C. S. Hinnant, Vice President Carolina Power & Light Company N. B. Robinson Steam Electric Plant, Unit No. 2 3581 West Entrance Road Hartsville, South Carolina 29550
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION REGARDING RESPONSE TO GENERIC LETTER 95-07, "PRESSURE LOCKING AND THERMAL BINDING OF SAFETY RELATED POWER-OPERATED GATE VALVES," FOR THE H. B. ROBINSON STEAM ELECTRIC PLANT, UNIT NO. 2 (TAC NO. M93512)
Dear Mr. Hinnant:
On August 17, 1995, the NRC issued Generic Letter (GL) 95-07, "Pressure Locking and Thermal Binding of Safety-Related Power-Operated Gate Valves," to request that licensees take actions to ensure that safety-related power operated gate valves that are susceptible to pressure locking or thermal binding are capable of performing their safety functions. By letters dated October 16, 1995, and February 13, 1996, you responded to the GL for the H. B. Robinson Steam Electric Plant, Unit No. 2 (HBR).
The NRC staff is evaluating your response and has identified a need for additional information, as discussed in the enclosure, to complete our review.
The information requested by this letter is within the scope of the overall burden estimated in Generic Letter 95-07, "Pressure Locking and Thermal Binding of Safety-Related Power-Operated Gate Valves," which was a maximum of 75 hours8.680556e-4 days <br />0.0208 hours <br />1.240079e-4 weeks <br />2.85375e-5 months <br /> per response. This request is covered by Office of Management and Budget Clearance Number 3150-0011, which expires July 31, 1997.
Your written response is expected within 30 days of receipt of this request for additional information. Should you have any questions, do not hesitate to contact me at (301) - 415-2020.
Sincerely, (Original Signed By)
Brenda Mozafari, Project Manager Project Directorate II-1 Division of Reactor Projects -
I/II Office of Nuclear Reactor Regulation Docket No. 50-261
Enclosure:
Request for Additional Information cc w/enclosure:
See next page FILENAME -_G:\\ROBINSON\\ROB93512.RAI OFFICE LA:PDII-1 PD:PDII-1 NAME Dunning z far Elmbro
_2_
DATE 7/-3/96 7/-3/96 7//96 COPY Yes No Yes$
OFFICIAL COPY 9607100215 960703R PDR ADOCK 05000261 P
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 Manager Nuclear Services and Environmental Mr. Dale E. Young Support Department Plant General Manager Carolina Power & Light Company Carolina Power & Light Company Post Office Box 1551 - Mail OHS7 H. B. Robinson Steam Electric Plant Raleigh, North Carolina 27602 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 Mr. R. M. Krich Manager - Regulatory Affairs Carolina Power & Light Company H. B. Robinson Steam Electric Plant, Unit No. 2 3581 West Entrance Road Hartsville, South Carolina 29550
REQUEST FOR ADDITIONAL INFORMATION H.B. ROBINSON STEAM ELECTRIC PLANT, UNIT NO. 2.
RESPONSE TO GENERIC LETTER 95-07, "PRESSURE LOCKING AND THERMAL BINDING OF SAFETY-RELATED POWER-OPERATED GATE VALVES"
- 1.
Address the potential susceptibility of valves SI-867A/B, boron injection tank inlet isolation valves, to depressurization induced pressure locking during a design basis event.
- 2.
The submittal dated February 13, 1996, discusses the potential susceptibility of valves RC-535 and RC-536, pressurizer power operated relief valves (PORVs) to thermal binding. You state that these valves have Limitorque SB-00 actuators, which have spring compensators.
Discuss any diagnostic test data you have to show that these spring compensators will avoid excessive closing forces.
You also describe the potential susceptibility of these valves to pressure locking during a steam generator tube rupture (SGTR) accident.
The submittal, further, indicates that the PORV block valves are considered operable since the use of the PORV block valves to control reactor coolant system pressure is not a primary function for the mitigation of a SGTR accident and if these valves fail to open the reactor coolant pressure boundary will not be affected. If available, provide thrust requirement and actuator capability calculations to support your position.
- 3.
In Attachment 1 to Generic Letter (GL) 95-07, "Pressure Locking and Thermal Binding of Safety-Related Power-Operated Gate Valves," the NRC staff requested that licensees include consideration of the potential for gate valves to undergo pressure locking or thermal binding during surveillance testing. During workshops on GL 95-07 in each Region, the NRC staff stated that, if closing a safety-related power-operated gate valve for test or surveillance defeats the capability of the safety system or train, the licensee should perform one of the following within the scope of GL 95-07:
- 1.
Verify that the valve is not susceptible to pressure locking or thermal binding while closed,
- 2.
Follow plant technical specifications for the train/system while the valve is closed,
- 3.
Demonstrate that the actuator has sufficient capacity to overcome these phenomena, or
- 4.
Make appropriate hardware and/or procedural modifications to prevent pressure locking and thermal binding.
The staff stated that normally open, safety-related, power-operated gate valves that are closed for test or surveillance but must return to the open position should be evaluated within the scope of GL 95-07.
Please discuss if valves that meet this criterion were included in your review, and how potential pressure locking or thermal binding concerns were addressed.
-2
- 4.
Through review of operational experience feedback, the staff is aware of instances where licensees have completed design or procedural modifications to preclude pressure locking or thermal binding which may have had an adverse impact on plant safety due to incomplete or incorrect evaluation of the potential effects of these modifications.
Please describe evaluations and training for plant personnel that have been conducted for each design or procedural modification completed to address potential pressure locking or thermal binding concerns.
July 3, 1996 Distribution DoketF ile PUBLIC PDII-1 RF S. Varga J. Zwolinski OGC ACRS R. Eaton H. Rathbun R. Wessman M. Shymlock, RH