ML20141C619
| ML20141C619 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 06/23/1997 |
| From: | Labarge D NRC (Affiliation Not Assigned) |
| To: | Hampton J DUKE POWER CO. |
| References | |
| TAC-M93492, TAC-M93493, TAC-M93494, NUDOCS 9706250347 | |
| Download: ML20141C619 (5) | |
Text
l June 23, 1997 I
.F j
l Mr. J. W. Hampton Vice President, Oconee Site Duke Power Company P. O. Box 1439 l
Seneca, SC 29679
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION - GENERIC LETTER 95-07, " PRESSURE i
LOCKING AND THERMAL BINDING OF SAFETY-RELATED POWER-0PERATED GATE VALVES," OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3 (TAC NOS. M93492, M93493, AND M93494)
Dear Mr. Hampton:
On August 17, 1995, the NRC issued Generic Letter (GL) 95-07, " Pressure Locking and Thermal Binding of Safety-Related Power-0perated Gate Valves," to l
request that licensees take actions to ensure that safety-related power-operated gate valves that are susceptible to pressure locking or thermal l
binding are capable of performing their safety functions.
By letters dated October 16 and November 15, 1995, and January 6, February 13, l
and July 18, 1996, you submitted responses to GL 95-07 and a staff request for additional information dated June 13, 1996, for the Oconee Nuclear Station, l
Units 1, 2, and 3.
Based on our review of your submittals, the staff has determined that additional information is necessary to complete our safety evaluation, as described in the enclosure.
We request that you respond to this request within 60 days.
Sincerel[, SIGNED BY:
ORIGINA David E. LaBarge, Senior Project Manager l
Project Directorate 11-2 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation i
Docket Nos. 50-269, 50-270, and 50-287 Ok
Enclosure:
Request for Additional Information cc w/ encl:
See next page
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June 23, 1997 Mr. J. W. Hampton Vice President, Oconee Site Duke Power Company P. O. Box 1439 Seneca, SC 29679
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION - GENERIC LETTER 95-07, " PRESSURE LOCKING AND THERMAL BINDING OF SAFETY-RELATED POWER-0PERATED GATE i
VALVES," OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3 (TAC NOS. M93492, i
M93493, AND M93494)
Dear Mr. Hampton:
On August 17, 1995, the NRC issued Generic Letter (GL) 95-07, " Pressure Locking and Thermal Binding of Safety-Related Power-0perated 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.
i By letters dated October 16 and November 15, 1995, and January 6, February 13, l
and July 18, 1996, you submitted responses to GL 95-07 and a staff request for additional information dated June 13, 1996, for the Oconee Nuclear Station, Units 1, 2, and 3.
Based on our review of your submittals, the staff has determined that additional information is necessary to complete our safety i
evaluation, as described in the enclosure. We request that you respond to this request within 60 days.
Sincerely, David E. LaBarge, Senior Project Manager Project Directorate 11-2 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation j
1 Docket Nos. 50-269, 50-270, and 50-287
Enclosure:
Request for Additional Information cc w/ encl:
See next page
Oconae Nuclear Station Units 1, 2, and 3 I
cc:
l Mr. Paul R. Newton Mr. J. E. Burchfield Legal Department (PB05E)
Compliance Manager Duke Power Company Duke Power Company t
422 South Church Street Oconee Nuclear Site Charlotte, North Carolina 28242-0001 P. O. Box 1439 Seneca, South Carolina 29679 J. Michael McGarry, III, Esquire Winston and Strawn Ms. Karen E. Long 1400 L Street, NW.
Assistant Attorney General Washington, DC 20005 North Carolina Department of Justice l
Mr. Robert B. Borsum P. O. Box 629 Framatome Technologies Raleigh, North Carolina 27602 Suite 525 1700 Rockville Pike Mr. G. A. Copp Rockville, Maryland 20852-1631 Licensing - EC050 Duke Power Company Manager, LIS 526 South Church Street NUS Corporation
. Charlotte, North Carolina 28242-0001 2650 McCormick Drive, 3rd Floor Clearwater, Florida 34619-1035 Senior Resident Inspector U. S. Nuclear Regulatory Commission Route 2, Box 610 Seneca, South Carolina 29678 i
i Regional Administrator, Region II U. S. Nuclear Regulatory Commission Atlanta Federal Center 61 Forsyth Street, S.W., Suite 23T85 Atlanta, Georgia 30303 Max Batavia, Chief Bureau of Radiological Health South Carolina Department of Health and Environmental Control 2600 Bull Street Columbia, South Carolina 29201 County Supervisor of Oconee County Walhalla, South Carolina 29621 l
Mr. Dayne H. Brown, Director Division of Radiation Protection North Carolina Department of Ehvironment, Health and Natural Resources P. O. Box 276B7 Raleigh, Nor,th Carolina 27611-7687
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l l
REQUEST FOR ADDITIONAL INFORMATION l
OCONEE NUCLEAR STATION UNITS 1. 2 AND 3
!~
RESPONSE TO GENERIC LETTER 95-07 1
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l 1.
The February 13 and July 18, 1996, submittals stated that pressure L
locking and thermal binding long-term corrective actions would be fully implemented in Unit I by end-of-cycle (EOC) 17 refueling outage i
i l
scheduled for May 1997, in Unit 2 by EOC 16 refueling outage scheduled l
for October 1997, and in Unit 3 by E0C 16 refueling outage scheduled for i
December 1996.
Confirm that the corrective actions have been completed l
or will be completed as scheduled.
l 2.
The February 13 submittal stated that valves 1, 2 LP-017, 018
'and 2 low pressure injection A and B isolation valves), are sus (Unit 1 l
ceptible to thermal binding, and that procedures would be modified to periodically cycle the valves or a detailed thermal binding analysis would be performed as long-term corrective action. Describe the corrective action that was implemented to resolve the thermal binding concerns.
If a thermal binding analysis was performed, provide a i
l description of the methodology used and the results of your analysis for our review.
+
l 3.
The February 13 submittal stated that valves 1, 2, 3 LP-1, 2 (low pressure injection return block valves from reactor coolant system) and i
l 2,.3 LP-3 (low pressure injection return block valves from reactor l
l coolant system / secondary boron dilution valves) are not susceptible to thermal binding because operational experience shows that these valves do not thermally bind.
Discuss operating experience that demonstrates l
that these valves are not susceptible to thermal binding.
Include historical wedging and unwedging forces and any modifications implemented that may have made the valves more susceptible to thermal l
binding.
For example, increasing actuator output thrust causes the disk to wedge more tightly into the seat ~ making the valve more susceptible to thermal binding. Also, please describe any procedure modifications implemented to minimize the potential for thermal binding.
4.
The February 13 submittal stated that the Commonwealth Edison pressure locking prediction methodology was used to demonstrate that valves 1, 2, 3 CCW-287 (safe shutdown facility auxiliary service water discharge valves) would open during a pressure locking condition.
Provide 1, 2, 3 CCW-287 pressure locking, actuator capability, and thermal induced l
pressure calculations for our review.
l 5.
The February 13 submittal stated that valves 1, 2, 3 CCW-287 (safe shutdown facility auxiliary service water discharge valves); 1, 2, 3 HP-428 (reactor coolant return from letdown line valves); and 1, 2, 3 l
SF-97 (reactor coolant return from letdown line valves) are susceptible l
to thermal induced pressure locking.
The submittal stated that below 130*F,, a thermal induced pressurization rate of 5 psi /*F was assumed, i
i Enclosure i.
i 1.
and between 130*F and 450*F, a 23 psi /*F thermally induced pressurization rate was assumed.. Walworth flexible wedge and Anr. hor Darling double disk gate valve test results obtained from testing sponsored by the NRC, conducted by Idaho National Engineering and Environmental Laboratory (INEEL), identified that thermal pressurization begins when the air that is entryped in the fluid collapses and that there is not a temperature thre sid at which thermal pressurization rates change. The testing cond sted by INEEL, identified that for temperatures up to 250*F, when t e air in the fluid collapses, the thermal pressurization rate was 50 psi /*F.
These test results have been placed in the NRC's Public Doccment Room.
Explain the basis for your thermal induced pressure assumptions and why yaur thermal induced pressurization rates are different than the INEE'. test results.
6.
The February 13 submittal stated that calculations were used to demonstrate that valves 1, 2, 3 HP-428 (reactor coolant return from letdown valves) are capable of opening under pressure locking conditions. A double disk gate valve pressure locking prediction methodology was used.to calculate the thrust required to open the valves during pressure locking conditions.
Provide the test procedure /results that validated this pressure locking prediction methodology and the information necessary to evaluate if valves 1, 2, 3 HP-428 are similar to the test valves. Recent pressure locking testing sponsored by the NRC and performed by INEEL indicated that thrust requirements exceeded double disk pressure locking prediction calculation results. The results of this testing have been placed in the NRC's Public Document 3
Room. Discuss if these INEEL pressure locking test results.can be used to validate your double disk gate valve pressure locking prediction methodology.
Provide 1, 2, 3 HP-428 pressure locking, actuator capability, and thermal induced ~ ressure calculations for our review.
p 7.
The February 13 submittal stated that valve 2 LP-3 (low pressure injection return from reactor coolant system / secondary boron dilution valve) is susceptible to pressure locking.
The submittal stated that the valve would be modified to prevent pressure locking or procedures would be revised to stroke the valve prior to startup to alleviate pressure locking concerns. What corrective action was' implemented? If procedures were revised to stroke the valve, explain why the valve bonnet will not be pressurized to reactor coolant system pressure and susceptible to pressure locking when opening the valve to place shutdown cooling in. operation.
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