ML13322A584
| ML13322A584 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 09/12/1979 |
| From: | Ziemann D Office of Nuclear Reactor Regulation |
| To: | James Drake Southern California Edison Co |
| References | |
| TASK-05-13, TASK-5-13, TASK-RR NUDOCS 7910040413 | |
| Download: ML13322A584 (3) | |
Text
DlLSTRIBUTI0N NRC PDR Local PDR ORB #2 Reading NRR Reading DLZiemann Docket No. 50-206 HSmith ABurger TJCarter WGAmmill SEP 1 2 1979 SMacKay GLainas Mr. James H. Prake OELD Vice President OJ&E (3)
Southern California Edison Company TRA 2244 Walnut Crove Avenue A
Post Office Box 800 Posemead, California 91770 DCrutchfield Dear.4r.
Drake:
RE:
STEAM GENERATOR WATER HANMER - SAN ONOFRE, UNIT 1 In response to our letter of September 2, 1977, regarding steam generator water hammer at San Onofre, Unit 1, you indicated that, based on your operating experience, modifications were not necessary to further reduce the proba bility or consequences of steam generator water hammer at your facility.
Although your operating history does not show that such water hammer has occurred in your present piping arrangement, we require further assurance that-steam generator water hammer will not occur in the future and that surveillance procedures would be adequate to detect water hammer or damage from water hammer if it were to occur.
Your response to the enclosed request for additional information, together with previously supplied information, will provide a bases for a determination regarding the need for modifications to your feedwater system to.prevent stean generator water hammer. Your response is needed within 60 days so that we may maintain our schedule for evaluating the potential for water hammer at your facility.
Sincerely, Original zigned by age3 j L'. Ziemann Dennis L. Ziemann, Chief Operating Reactors Branch #2 Division of Operating Reactors
Enclosure:
7910040 Request for Additional DOR:ORB #2 DOR:ORB #2 cc n osure:.ABurger:ah DLZiemann MURNAM
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SeDtember 12, 1979 cc w/enclosure:
Charles R. Kocher, Assistant General Counsel Southern California Edison Company Post Office Box 800 Rosemead, California 91770 David R. Pigott Samuel B. Casey Chickering & Gregory Three Embarcadero Center Twenty-Third Floor San Francisco, California 94111 Jack E. Thomas Harry B. Stoehr SanDiego Gas & Electric Company P. 0. Box 1831 San Diego, California 92112 U. S. Nuclear Regulatory Commission ATTN:
Robert.J.
Pate P. 0. Box 4167 San Clemente, California 92672 Mission Viejo Branch Library 24851 Chrisanta Drive Mission Viejo, California 92676
REQUEST FOR ADDITIONAL INFORMATION ON STEAM GENERATOR WATER HAMMER SAN ONOFRE, UNIT 1 DOCKET NO. 50-206
- 1. Provide information that demonstrates that the feedwater system and steam generator water level at your facility have been subjected to those transient conditions that are conducive to water hammer, i.e., the addition of cold feedwater or auxiliary feedwater to steam-filled feedwater piping and feedring. See NUREG 0291 Page 4 that was forwarded to you on September 2, 1977.
Include the following:
1.1 Describe the expected behavior of steam generator water level as a result of reactor trip from power levels greater than 30% of full power. Include actual plant measurements of steam generator level and other available related data such as feedwater flow and auxiliary feedwate:r flow.
1.2 Provide the number and causes of loss of fcedwater events during the operational history of the plant. You may refer to material submitted previously.
1.3 Provide the number and causes of loss of off-site power events during the operational history of the plant.
- 2. If administrative controls have been adopted to limit the flow of auxiliary feedwater for the purpose of reducing the probability of water hammer, show when they were adopted and give the answers to items 1.1, 1.2 and 1.3 for before and after such controls were established.
- 3. If administrative controls have been adopted to limit the flow of auxiliary feedwater for the purpose of reducing the probability of water hammer, show that an adequate water inventory and flow will be maintained to accommodate all postulated transient and accident conditions.
- 4. If auxiliary feedwater flow in your facility is not at present initiated automatically for normal and accident events, present your evaluation of whether automating the actuation of auxiliary feedwater might increase the probability of inducing steam generator water hammer.
One of the signals that would automatically initiate the flow of auxiliary feedwater would be the steam generator low water level.
This set point should be above the top of the main feedwater sparger to reduce the probability of steam generator water hammer.
- 5. Describe the means that will be used to monitor for the occurrence of steam generator water hammer and possible damage from such an event.
Include all instrumentation that will be employed.
Describe the inspections that will be performed and give the frequency of such inspections.
- 6. Describe the reporting procedures that will be used to document and report water hammer and damage to piping and piping support systems.
Such reports were requested in our letter to you dated September 2. 1977.