ML20137Y360
| ML20137Y360 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 11/23/1985 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20137Y353 | List: |
| References | |
| NUDOCS 8512110034 | |
| Download: ML20137Y360 (5) | |
Text
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NUCLEAR REGULATORY COMMISSION o
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 47 TO FACILITY OPERATING LICENSE NPF-12 SOUTH CAROLINA ELECTRIC & GAS COMPANY SOUTH CAROLINA PUBLIC SERVICE AUTHORITY VIRGIL C. SUPNER NUCLEAR STATION, UNIT 1 1.
INTRODUCTION By letters dated October 8, 1982, April 26, 1984, August 2 and September 25, 1985, the South Carolina Electric & Gas Company (the licensee) proposed certain changes to the facility Technical Specifications (TS) concerning Appendix J leakage rate testing of certain containment isolation valves.
The licensee proposes to change TS Table 3.6-1, " Containment Isolation Valves," as follows:
(1)
Two valves in the dead weight tester system would be deleted from the table; (2)
Six valves in the reactor coolant pump seal injection lines would have footnotes added to indicate that they are not subject to Type C (local) leakage rate testing; and (3)
Two valves in the Residual Heat Removal (RHR) system pump suction lines from the reactor coolant systwi would also be footnoted as not subject to Type C testing.
II.
EVALUATION Dead Weight Tester System Valves 809A and B These two valves are being removed as a result of a plant modification.
The penetration will then be plugged and seal-welded closed, and will no longer require local leakage rate testing. Therefore, the staff concludes that it is appropriate to delete these valves from TS Table 3.6-1.
Reactor Coolant Pump Seal Injection Valves SVT-8102 A, B, and C-CS; XVC-8368 A, B, and C-C5 Valves 8102 A, B, and C are reactor coolant pump seal injection line globe valves located outside of containment. Valves 8368 A, B, and C are seal injection line check valves located inside containment on the same lines as the 8102 valves. These lines are filled with water from the charging system via the charging pumps. These line sense a pump.
discharge pressure of 2700 psig.
8512110034 851123 PDR ADOCK 05000395 P
The seal injection system is nomally in service and in operation at all times, except when the plant is in cold shutdown and reactor coolant pump seal maintenance is required. In the event of an accident, e.g.,
a large break LOCA, the seal injection system remains in operation receiving water from the charging pumps and injecting into the Reactor Coolant pump seals. During all phases of the accident (injection - cold leg recirculation - hot leg recirculation), the seal injection system continues to inject water into the Reactor Coolant pump seals to ensure the pump seals remain cooled. If closed during an accident condition, such as for a suspected seal injection line break, the charging pumps will maintain pump discharge pressure against the outside containment side of the valve. In addition, valve leakage through the valve leakoffs would come from the higher pressure side of the valves. This would be the charging pump side (outboard) of the 8102' valves. The 8368 valves do not have valve leakoffs, since they are check valves. There are no plant pro-cedures which require closure of the seal injection valves during the first 30 days after onset of the accident.
During a safety injection and subsequent containment isolation, charging pump suction water is provided by the refueling water storage tank (RWST).
Once this supply is exhausted, suction is automatically switched to the reactor building sump. Therefore, an inventory of water is always assured.
Valves 8102 A, B, -C and 8368 A, B, C are part of the seal water injection portion of the Safety Injection System B Train. Due to nomally'open cross-tie valves, the Safety Injection System A and B Trains are designed to operate with a single failure of any active component. Operability of the containment isolation valves is not required to maintain a water seal.
Therefore, with the exception of " Loss of Offsite Power," at least one charging pump maintains pressure in both trains (A and B) for all accident scenarios involving a containment isolation signal. During " Loss of Offsite Power," the charging pumps will lose power for approximately 10 seconds while the diesel generators are starting. Since the lines remain filled with water during this period, there would not be leakage of con-tainment atmosphere through these lines. All piping and components required to maintain the water seal are ASME safety class 2 or better and seis:aic Category I.
Based on the foregoing, the staff concludes that the subject valves will remain sealed with water during a LOCA and do not constitute potential containment atmosphere leak paths. Therefore, Appendix J does not require that they be Type C tested, and TS Table 3.6-1 may be revised to note that they are not subject to Type C testing.
Residual Heat Removal System Valves SVG-8701A and B-RH Valves 8701 A and B provide containment isolation for the Residual Heat Removal (RHR) system pump suctions from the reactor coolant system. They are gate valves located just inside containment. For these valves, the water seal consists of water filled piping that rises from the inboard side of these valves. This piping is outside the missile barrier and is not subject to pipe break as a result of the accident. Since the a
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8701 valves are inside containment, valve leakage from valve leakoffs remains inside the containment. Therefore, the water seal is bounded by the containment isolation valve and the point where the pipe penetrates the missile barrier. The water volume in the piping bounded by these two points is the thirty day inventory. Water leakage through the valve over thirty days must be less than that volume and is to be verified by a leak rate test performed in accordance with station procedures and the TS bases. These valves are motor operated but have no automatic function to change position under signals such as safety injection or Phase A or B isolation. The valves require operator action to open or close. They also have interlocks to prevent inadvertent operator opening during Modes 1, 2 and 3.
The valves fail as-is and, therefore, are considered to remain closed in Modes 1, 2 and 3.
Therefore, there are no active components whose failure would affect the water seal in these Modes.
In Mode 4 these valves are opened to initiate RHR. If one fails open, then the valve is not performing a containment isolation function and its leakage characteristics are of no consequence. If the valves close, there would not be loss of water inventory while the valves are closing, because there is auther vertical riser of pipe on the outboard of the valves. Therefore, the water seal would be maintained as necessary in Mode 4.
All piping and components required to maintain the water seal, including the vertical riser on the outboard of the valves, are ASME safety class 2 or better and seismic Category I.
Based on the foregoing, the staff concludes that the subject valves will remain sealed with u te* during a LOCA and do not constitute potential containmer* atmosphere {aak paths. Therefore, Appendix J does not require that they te Type C tested, and TS Table 3.6-1 may be revised to note that they are not subject to Type C testing.
Therefore, the staff concludes that the proposed ' changes to TS Table 3.6-1 are acceptable.
III. ENVIRONMENTAL CONSIDERATION This amendment involves a change in the installation and use of facility component located within the restricted area as defined in 10 CFR Part 20 and changes in surveillance requif onents. The staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that r.ay be released offsite and that there is no-significant increase in individual or cumula-tive occupational radiation exposure. The Comission has previously.fssued a proposed finding that this amendment involves no significant hazards consideration, and there has been no public coment on such finding..
Accordingly, this amendment meets the eligibility criteria for categorical exclusionsetforthin10CFRSec51.22(Od9). Pursuant to 10 CFR 51.22(b) no environmental impact statement or et h nmental asse n ment need be prepared in connection with the issuance of this amendment.
-4 IV. CONCLUSION The Commission made a proposed determination that the amendment involves no signficant hazards consideration which was published in the Federal Register (50 FR 4303))on October 23, 1985, and consulted with the state of South Carolina. No public comments were received, and the state of South Carolina did not have any comments.
We have concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Commission's regulations, and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributors:
Jon B. Hopkins, Licensing Branch No. 4. DL James C. Pulsipher, Containment Systems Branch, DSI Dated: November 23, 1985 m
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November 23, 1985 AMENDMENT NO. 47 TO FACILITY OPERATING LICENSE NO NPF Virgil C. Sumer Unit 1 DISTRIBUTION w/ enclosures:
ket No. 50-395 NRC PDR Local PDR NSIC PRC System LB #4 r/f J. Hopkins M. Duncan Attorney, OELD E. Adensam R. Diggs, ADM T.Barnhart(4)
J. N. Grace, DPR:I&E E. L. Jordan, DE0A:I&E L. Harmon, I&E J. Partlow B. Grimes M. Virgilio J. Pulsipher, CSB
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