ML13333A736
| ML13333A736 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 04/06/1981 |
| From: | Haynes J SOUTHERN CALIFORNIA EDISON CO. |
| To: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| IEB-80-24, NUDOCS 8104240249 | |
| Download: ML13333A736 (4) | |
Text
Southern California Edison Company P. 0. BOX Boo 2244 WALNUTGROVEAVENUE ROSEMEADCALIFORNIA 91770 J. G. HAYNES TELEPHONE MANAGER OF NUCLEAR OPERATIONS April 6, 1981 (213) 572-1742 U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement
\\
Region V Suite 202, Walnut Creek Plaza 1990 North California Boulevard 9
,T Walnut Creek, California 94596 01 2019 Attention: R. H. Engelken, Director
,1 Gentlemen:
l
Subject:
Docket No. 50-206 IE Bulletin No. 80-24 Prevention of Damage Due to Water Leakage Inside Containment San Onofre Nuclear Generating Station Unit 1 By letter dated March 23, 1981, we provided our response to IE Bulletin No. 80-24. Subsequent review has revealed that the response erroneously characterized the service water supply requirements of the sphere sump pumps.
The March 23 letter stated that the recently-replaced sphere sump pumps no longer require service water for bearing lubrication; however, this is not the case, and the sphere sump pumps do indeed require service water for proper operation. This error was reported to Mr. A. E. Chaffee of your staff on March 31, 1981.
Corrected pages for the enclosure to the March 23 letter are attached. We regret any inconvenience this might have caused.
If you have any questions concerning this matter, please contact me.
Subscribed on this day of
/ 4, 1981.
ByIC J. G. Haynes/
Manager of Nuclear Operations GNEALBTR Subscribed and swor to before me this AGNES CRABTREEof
""19.
NOrARY PUBLIC - CALIFORNIA day of e
/
, 1981.
PRINCIPAL OFFICE IN LOS ANGELES COUNTY My Comrmssion Ep. Aug.27, 1982 Notar Public in and for the County of Los Angeles, State of California cc:
Director, Office of Inspection and Enforcement 8 1042402.49
Item 1 Provide a summary description of all open cooling water systems present inside containment.
Response
The service water system is the only open system inside containment, because its water supply is the service water reservoir.
The use of service water in the containment is very limited. The nine service water hose stations are normally closed and opened manually when they are used. This allows the operator to examine the valve on completion of use and inspect to make sure it is not leaking when closed. The bearing lubrication water to the sphere sump pump, reactor sump pump, and recirculation pumps is used only when the pumps are operating. This is accomplished by using solenoid actuated valves that open the service water line to the pump when it is operating. See Attachment 1 for further information. It should be noted that flow of water into containment via the service water system is an infrequent occurrence because the hose stations are normally closed, the recirculation pumps are not used, the reactor sump pumps are operated infrequently, and the sphere sump pumps operate about every two to seven days.
Item 1(a)
Mode of operation during routine reactor operation and in response to a LOCA.
Response
The containment isolation valves of the service water system remain open during normal operation and are closed in response to a LOCA condition.
Bearing lubrication for each recirculation pump is provided by a system internal to the pump during a LOCA condition.
The reactor sump pump is neither used nor required in a LOCA condition. The sphere sump pump is deenergized upon activation of the high level sump alarm in a LOCA condition.
Item 1(b)
Source of water and typical chemical content of water.
Response
Water for the service water system is supplied by the service water reservoir. See Attachment 1(b) for the chemical analysis of the water.
Item 1(c)
Materials used in piping.
Response
A complete description of the piping specification, size, ASTM number, operating temperature and pressure may be found in Attachment 1(c).
-2 Item 1(d)(e)
Experience with system leakage.
History and type of repairs to coolers and piping systems (i.e., replacement, weld, braze, etc.).
Response
In order to respond to this item, the service water system in the containment was researched using the applicable P&ID's, system descriptions, and cognizant personnel at San Onofre Unit 1. The investigation of leaks inside the containment was done using the maintenance records, the station incident reports, and contacts with the watch engineers and reactor operators. These records and interviews reveal only one report of leakage of the service water system inside containment.
On February 4, 1977, a Request for Equipment Repair for the west sphere sump pump was originated due to water leaking through the solenoid valve. At that time San Onofre Unit 1 was down for a scheduled refueling outage. The repair was completed on March 14, 1977 by cleaning out the solenoid valve. The originator of the Request for Equipment Repair recalls the following:
The sphere sump pump usually operates about once every two to seven days, and any operation which occurs more frequently than every two days will alert the watch engineer to investigate. In this instance, the sphere sump pump operated about every four hours, which is estimated to be a leak rate through the valve of two gallons per minute. After the repair in 1977, this has happened once or twice; in each case, the leak was stopped by closing the associated containment isolation valve.
Upon opening the containment isolation valve, the problem in the solenoid valve had corrected itself.
No record of any other leak of the service water system inside containment has been found.
Item 1(f)
Provisions for isolating portions of the system inside containment in the event of leakage including vulnerability of those isolation provisions to single failure.
Response
The service water system has two containment isolation valves, one inside (CV-537) and one outside (CV-115), which are powered by F-train and G-train, respectively, to insure against a single failure. Both valves close on containment isolation.
SERVICE WATER OUTLETS TO SUMP PUMPS FOR BEARING LUBRICATION Pump No.
Actuating Solenoid Valve Recirculation Pumps G-45A SV-37 G-45B SV-38 Sphere Sump Pumps G-21A SV-73 G-21B SV-36 Reactor Sump Pump G-39 SV-71 COMPONENTS Service Water Pumps (G-14A and G-17B)
Capacity per pump at design pressure 300 gpm Design differential pressure 47 psi NPSH required 26 feet (11.3 psi)
OPERATION One service water pump is normally in operation maintaining a system pressure 70 psig with the second pump automatically started by pressure switch PS-48 and PS-49 if the service water header pressure drops to 35 psig. An alarm will annunciate upon automatic starting of the second pump. The pump switches and alarms are on the vertical board in the control room.
The Service Water System pressurizes the Fire Protection System when the fire system is not in use.