ML13317A731
| ML13317A731 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 11/18/1981 |
| From: | Krieger R Southern California Edison Co |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| TASK-06-04, TASK-6-4, TASK-RR NUDOCS 8111190782 | |
| Download: ML13317A731 (11) | |
Text
Southern California Edison Company P.O. BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD, CALIFORNIA 91770 Director, Office of Nuclear Reactor Regulation Attention: D. M. Crutchfield, Chief Operating Reactors Branch No. 5 Division of Licensing U. S. Nuclear Regulatory Commission Washington, D.C.
20555 Gentlemen:
Subject:
Docket 50-206 Information for SEP Topic VI-4, Containment Isolation Systems San Onofre Nuclear Generating Station Unit 1 Your letter of July 27, 1981 requested additional information for your evaluation of SEP Topic VI'-4, Containment Isolation Systems of San Onofre Unit 1. The requested information is provided as enclosures to this letter.
If you have any questions or desire additional information regarding this subject, please contact me.
Very truly yours, R. W. Krieger Supervising Engineer, San Onofre Unit 1 Licensing Enclosure (8111190782 81111W>
Ft/
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INFORMATION FOR SEP TOPIC VI-4, SAN ONOFRE UNIT 1 Item 1:
Provide a table similar to Table 4.3 of the FSAR, "Valves Required for Containment Isolation."
Include information on the new isolation valves, mentioned in Table 3.2-1 of Amendment 52 to the FSAR.
Response: is a modified Table 3.2-1 from Amendment 52, including new valve identification and information as were presented on Table 4.3. The information includes position during operation, method of actuation, and fail safe mode, and has been condensed to omit lines without isolation valves such as Feedwater and Condensate System lines and other lines listed on Sheets 6 and 7 of Table 3.2-1.
The valves (omitted from modified table) which are closed by a containment isolation actuation signal and the sampling lines they isolate are listed below:
SV-702 A&B, line 6107-3/4" SV-702 C&D, line 6108-3/4" SV-119, line 1201-1/4"-EG1 SV-123, line 1207-3/8"-EG1 SV-120, line 1202-1/4"-EG1 SV-122, line 1208-3/8"-EG1 SV-121, line 1203-1/4"-EG1 SV-124, line 1209-3/8"-EG1 Item 2:
Identify all containment penetrations, including piping penetrations, spare penetrations, fuel transfer tube, equipment hatch and personnel airlock(s). For the airlock(s), show the isolation provisions for test instrument and other lines that penetrate the airlock and airlock doors.
Where blind flanges are used, verify that the capability exists for leak testing.
Response
All piping penetrations and spares are identified on drawing 715337. The Equipment Access Hatch, the Escape (Air) Lock and the Personnel Air Lock are identified on drawing 715337. The electrical penetrations and spares are identified on drawing 432587. The spare electrical penetrations have blind flange closures.
All are tested (Type A) with the containment.
The air locks, the test arrangements for which are shown on drawing 568780, have only'a single piping penetration for the test functions of pressurizing and pressure monitoring. This penetration is in the outer barrier, leaving the inner barrier intact. Although no isolation provisions are required, there are normally closed valves (not redundant) in the test line for filling and venting.
As discussed in response to Item 5 below, the drawings referenced above are enclosed.
Item 3:
Identify the signals which isolate the automatic isolation valves, and specify the parameters sensed for each signal.
Response
The containment isolation actuation signal for each of the two Containment Isolation System trains is generated by high containment pressure, by safety injection initiation or by manual initiation in the main control room.
The high containment pressure signal is generated based on 2 out of 3 transducers sensing high pressure.
-2 The pressure switches PS-23 and PS-117 originally used for containment isolation, have been replaced by six new pressure transmitters, three aligned with each train.
The safety injection actuation signal is generated by either Safeguard Load Sequencing System train (sequencers 1 and 2).
The initiation of this signal is by sequencer logic of 2 out of 3 low pressurizer pressure, by sequencer logic of 2 out of 3 high containment pressure or by manual initiation.
In addition, a signal from the containment radiation monitor channel R-1212 will close of POV-9,-10, CV-10, -40 and CV-116 in containment purge and vent lines.
Item 4:
Table 4.3 of the FSAR references Supplement 1 where lines are considered to be extensions of the containment. Since we no longer have Supplement 1, please provide the appropriate information when providing the table requested (Item 1).
Response
For completeness, Enclosure 2 provides our response to Question 2 of Supplement 1, regarding extensions of containment. Additional information regarding exemptions of containment is provided by footnotes e.
and f. of Table 3.2-1 of Amendment 52.
Item 5:
Provide updated system design drawings which show the containment isolation provisions for piping systems that penetrate the containment.
Response
The mechanical and controls drawings relevant to the Containment Isolation System as listed below are enclosed. Some drawings have been revised but not yet updated. Where this is the case, the appropriate Configuration Changes have been identified and are enclosed.
blueline drawings 235410-1 5159704-1 432587-6 5159705-1 568767-21 5159717-1 half-size drawings with Configuration Changes 451355-1/CC # 4, 3, 2 568766-17/DCN 22/CC # 20, 19, 17, 16, 15, 13, 12 568768-15/CC # 15, 14, 13 568769-15/DCN 26, 25, 24, 23, 22, 20 568770-12/CC # 7 568772-22/CC # 15, 14/ DCN 13/CC # 12, 11, 10, 9, 8, 7 568773-13/CC # 3, 2, 1 568776-21/DCN 24/CC # 23/DCN 21, 20, 19/CC # 18, 17 568779-22 568780-18/CC # 15, 14, 13, 12, 11, 10, 9 568782-19/CC # 14, 12, 11 568783-11/CC # 2 568784-17/CC # 18/DCN 14, 13/CC # 12, 11, 10, 9 715337-0/DCN 1 Table 3.2-1 (Amendment 52), Modified CONTAINMENT ISOLATION VALVES (Sheet 1 of 4)
Posit.
Method Fail Boundary Penet.
During of Act-Safe Line Number System*
Service Inside Outside Number Opn.
uation Mode 734-6"-HP MWS Refueling water supply CV-92, 6"-900-25 B-18 NC,NO rm, m FOF 114, 82 611-300-241 NC,NC,c rm & I FO,FO 730-2"-KN MWS Service water header CV-537 CV-115 A-11 NO, NO rm FC 743-8"-KN MWS Cooling water to airhandling (a)
CV-516 A-9 NO rm units 756-8"-KN MWS Cooling water from air units (a)
CV-515 A-9 NO rm FC 892-4"-KN MWS Cooling water from air units (a) 4"-250-159 A-14 c
rm FC CV-515 NO 928-1.5"-HH CAS Instrument air header 1.5"-600-240 1.5"-600-161 A-13 c, NO c
1.5"-600-161 1.5"-600-240 NO, c
- a. Closed system, no isolation valve required inside containment.
- b.
Lines penetrate to free volume of sphere, and outside isolation valves are normally closed during plant operation.
- c. These lines are pressurized post-LOCA to maintain recirculation cooling or safety injection.
As such they are considered an extension of the containment boundary.
MWS = Miscellaneous Water System CAS = Compressed Air System A/C = Air Conditioning RCS = Reactor Cooling System CVCS = Chemical and Volume Control ACS = Auxiliary Coolant System RCSS = Reactor Cycle Sampling System RWDS = Radioactive Waste Disposal System rm,m,I= remote manual,
- manual, Instrument actuated NO,NC,c = normally open mormally closed, check
Table 3.2-1 (Continued)
CONTAINMENT ISOLATION VALVES (Sheet 2 of 4)
Posit.
Method Fail Boundary Penet.
During of Act-Safe Line Number System*
Service Inside Outside Number Opn.
uation Mode 953-2"-HH2 CAS Service air header 2"-600-240 SV-125 A-12 c, NO c, I FC 2"-600-146 NO m
24" Supply A/C Sphere purge air (b)
POV-9, 9A E-1
, NC I, m FC 24" Exhaust A/C Sphere exhaust air (b)
POV-10, 10A E-1
, NC I, m F
961-6"-HH3 A/C Instrument air exhaust CV-40, 116 CV-10 B-17 NO,NO,NC I
FC 1233-1"-KP3 A/C Sphere vapor sample CV-147 SV1212-9, B-18B NO, NO rm+I FC 1234-1"-KP3 A/C Sample return to sphere CV-146 SV1212-8, B-18B sporadic rm&I, I FC 1409-3/4"-HH RCS N2 to pressurizer relief tank 1"-600-239 CV-532 A-5 sporadic
-,rm+I FC 715-3"-HP RCS Primary makeup to pressurizer CV-533 CV-534 B-2 NC, NC rm+I FC relief tank 3006-2"-601R CVCS Reactor coolant letdown CV-525 CV-526 B-6 NO, NO rm FC 2014-3"-151R CVCS Seal water return CV-527 CV-528 B-8 NO, NO rm FC 3090-8"-152N ACS Containment cooling water to (a) 772B-8"-G32 A-1 NO m
residual heat exchanger 3029-8"-152N ACS Containment cooling water from (a)
TCV-601B A-1 NO m
residual heat exchanger 3064-8"-152N ACS Containment cooling water to (a) 772A-8"-G32 A-1 NO m
residual heat exchanger
Table 3.2-1 (Continued)
CONTAINMENT ISOLATION VALVES (Sheet 3 of 4)
Posit.
Method Fail Boundary Penet.
During of Act-Safe Line Number System*
Service Inside Outside Number Opn.
uation Mode 3033-8"-152N ACS Containment cooling water from (a)
TCV-601A A-1 NO m
residual heat exchanger 3069-3"-152N ACS Containment cooling water to (a) 728A-3"-G32 A-4 NO m
reactor coolant pump G-2A 3073-3"-152N ACS Containment cooling water from (a) 736A-3"-G32 A-4 NO m
reactor coolant pump G-2A 3068-3"-152N ACS Containment cooling water to (a) 728B-3"-G32 A-4 NO m
reactor coolant pump G-2B 3078-3"-152N ACS Containment cooling water from (a) 735B-3"-T32 A-4 NO m
reactor coolant pump G-2B 3067-3"-152N ACS Containment cooling water to (a) 728C-3"-G32 A-4 NO m
reactor coolant pump G-2C 3083-3"-152N ACS Containment cooling water from (a) 735C-3"-T32 A-4 NO m
reactor coolant pump G-2C 3094-2.5"-HH ACS Containment cooling water to (a) 2.5"-150-72 A-2 NO m
shield coolant coils 3095-2.5"-HH ACS Containment cooling water from (a) 2.5"-150-174 A-2 NO m
cooling coils 3066-3"-152N ACS Containment cooling water to (a) 728D-3"-G32 A-3 NC m
excess letdown heat exchanger 3085-3"-152N ACS Containment cooling water from (a) 735D-3"-T32 A-3 NC m
excess letdown heat exchanger 736D-3"-G32 NO m
Table 3.2-1 (Continued)
CONTAINMENT ISOLATION VALVES (Sheet 4 of 4)
Posit.
Method Fail Boundary Penet.
During of Act-Safe Line Number System*
Service Inside Outside Number Opn.
uation Mode 5029-3/8"-250R RCSS Pressurizer samples CV-951, CV-992 B-12 sporadic rm FC 953 5004-3/8"-2505R RCSS B&C loop samples CV-955, CV-957 B-12 sporadic rm FC 956 3008-3/8"-2505R RCSS Residual heat exchanger sample CV-962 CV-957 B-12 sporadic rm 5052-3/8"-2505R RCSS Pressurizer relief tank gas CV-948 CV-949 B-12 sporadic rm FC sample 7078-1.5"-HP2 RWDS Sphere sump pump discharge CV-102 CV-103 A-8 NO, NO rm+I FC 7076-2"-HP2 RWDS RCS drain tank pump discharge CV-104 CV-105 B-10 NO, NO rm+I FC 7073-2"-HP2 RWDS RCS drain tank gas relief CV-106 CV-107 C-2 NO, NO rm+I FC 1410-1"-HH RWDS N2 to RCS drain tank CV-536 CV-535 C-2 Nc, Nc rm+I FC Refueling water, SI, NA NA B-11 NA NA NA 737-8"-HP MWS(c) recirculation return Calibration gas supply SV-3004 SV-2004 B-16 Sporadic rm to hydrogen monitors NA = Not applicable.
Sheets 6 and 7 of Table 3.2-1 listed lines which had no containment isolation valves, these lines were omitted here.
SAN ONOFRE NUCLEAR GENERATING STATION UNIT I PAGES 5 - 7, 8, and 9 OF SUPPLEMENT No. 1 TO THE FINAL ENGINEERING REPORT AND SAFETY ANALYSIS APRIL, 1946 SOUTHERN CALIFORNIA EDISON COMPANY SAN DIEGO GAS & ELECTRIC COMPANY
QUESTION 2 It appears that, in several lines leading from pumps within the containment to external areas, isolation depends on the operation of single (nonredundant) valves. What is the justification for this design? Can a single circuit failure prevent the automatic isolation of the containment ventilation system? Are the isolation valves in the containment ventilation system designed to close against accident pressure?
ANSWER There are only two sets of pumps that transfer water from within the containment to external areas during plant operation. These -are:
(a)
Sphere sump pumps.
(b) Reactor coolant system drain tank pumps.
The sphere sump pump and reactor coolant system drain tank pumps are used to transfer contents of the tank and sump to the radioactive waste dis posal system. Each set of pumps discharges to a line that contains redundant isolation valves, one inside and one outside the containment sphere. These valves are solenoid actuated diaphragm valves that automatically close on a high containment pressure signal and can be remotely manually closed from the control room. All valves fail closed on loss of actuating power.
The line leading outside the sphere from the recirculation pump is an extension of the containment boundary. To prevent leakage from this piping, all piping connections leading to atmosphere are isolated and the piping itself is designed to withstand post-accident pumping pressure superimposed on the containment design pressure.
The attached table lists the piping connections to the recirculation piping, and the means of isolation.
Whenever the containment is sealed and the reactor is critical, the sphere ventilation valves will be in the closed position and backed up by blind flanges on the ambient air side. These valves are opened only to purge the sphere when.the reactor is in the hot shutdown condition. They are designed to close against a differential pressure of 50 psi.
An air storage tank is mounted near the valves with sufficient capacity to insure compressed air supply to the valve operators in the event station instrument air is lost.
Any one of three signals will close the sphere ventilation valves automatically. These signals are PS-23 or PS-117 (sphere pressure), and high radiation from channel R-1214 radiation monitoring system. The ventilation valves can also be remotely closed from the control room by a manual switch.
5-7
RECIRCULATION LOOP ISOLATION (Continued)
ISOLATION POINT DESCRIPTION MEANS OF ISOLATION
- 9. Line 2000-4"-151R Suction line from volume control Valve MOV LCV 1100C, check valve 236-4"-Ch2 Fig. 3.56 tank automatically closed prior to recirculation to prevent flow to volume control tank.
- 10. Line 2054-1"-151N Boric acid injection line Remotely operated valve FCV 1102B, check
-Fig.
3.56 valve 343-1"-c42 closed prior to recir culat ion.
- 11. Line 2052-2"-151R branches Line from boric acid transfer Remotely operated valve CV 334, check to line 2051-2"-151R pumps valve 335-2"-C42 closed prior to recir Fig. 3-56 culation.
- 12. Line 2052-2"-151R Connection from primary water Manual isolation valve 336-2"-T42, check branches to line supply valve 337-2"-Ch2 locked closed during plant 2056-2"-151 operation.
Opened only under administrative Fig. 3.56-control to flush lines.
- 13. Line 2010-1/2"-151R Provides relief protection to test Isolation provided by spring load check Fig. 3.56 pump suction and discharge lines valve, set point higher than sphere accident pressure and recirculation maximum operating pressure.
- 14. Lines 2031-2"-2502R, Miniflow lines for the charging Line has been revised to discharge to suction and 2033-2"-2502R PUMPS header. No isolation required as this is Fig. 3.56 now a closed loop.
- 15. Line 2014-3"-151R Seal water return line Closed loop within the Chemical and Volume Fig. 3.56 Control Systems.
Branches from seal water line have locked closed valves under ad ministrative control.
PAll Figure numbers refer to the Final Engineering Report and Safety Analysis pupscinaddshre ie avstpithghrta peeacdn
RECIRCULATION LOOP ISOLATION ISOLATION POINT DESCRIPTION MEANS OF ISOLATION
- 1. Line 729-8"-HP at refuel-Refueling water return line.
Is Remotely operated valve MOV-883, Check ing water storage tank.
suction header for refueling water valve, 8"-150-275 closed prior to re
- Figs. 4.11 and 5.1 pump and charging pumps.
circulating to prevent flow to refueling water storage tank.
- 2. Line 863-l"-HP Refueling water pump miniflow No isolation required.
This is a closed Fig. 4.11 recirculation line - returns to loop in the recirculation flow path -
not suction line.
a boundary point.
- 3. Line 764-2"-HP2 Connection to radwaste ion Manual isolation valve, 2"-600-34, locked exchangers closed during plant operation. Opened only under administrative control for cleanup of water in refueling water storage tank. This operation is normally performed during final phases of refueling.
- 4. Line 896-2"-HP Connection to spent fuel pit Manual isolation valve - 2"-150-83, locked Fig. 4.11 closed during plant operation. Opened only under administrative control for replenishment of spent fuel pit water.
- 5.
Line 888-l"-HP2 Drain connection at filter in Manual isolation valve, 1"-150-183, locked Fig. 4.11 refueling water line closed during plant operation. Opened only when filter is isolated.
- 6. Line 764-2"-HP2 Line to waste holdup tank Line is showrf erroneously; has been deleted Fig. 4.11
- 7. Line 891-2"-H7 Refueling line No isolation required.
This is a closed Fig. 4.11 loop in the recirculation flow path -
not a boundary point.
- 8. Line 736-1"-HP Return line from refueling water Manual isolation valve 4"-150-18; locked Fig. 4.11 transfer pump to refueling water closed. during plant operation. Opened storage tank.
only under administrative control for circulation of refueling water.