ML13336A075
| ML13336A075 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 04/22/1988 |
| From: | Trammell C Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8804290114 | |
| Download: ML13336A075 (29) | |
Text
April 22, 1988 Docket Nos.: 50-206 LICENSEE:
SOUTHERN CALIFORNIA EDISON COMPANY FACILITY:
SAN ONOFRE NUCLEAR GENERATING STATION, UNIT NO. 1
SUBJECT:
SUMMARY
OF MEETING HELD ON MARCH 16, 1988 REGARDING PROPOSED IMPROVEMENTS TO THE SAFETY INJECTION SYSTEM - SAN ONOFRE UNIT 1 On March 16, 1988, the NRC staff met with representatives of Southern California Edison (SCE) to discuss alternatives to improving the Safety Injection System (SIS) at San Onofre Unit No. 1. Attendees are listed in Attachment No. 1. Handout material presented at the meeting is shown in Attachment No. 2. The meeting was held pursuant to notice dated March 9, 1988.
SCE originally proposed to add a fully qualified dedicated SIS but, on the strength of a detailed probability risk assessment (PRA), concluded that such a system would not provide enhancements in core damage risks commensurate with the costs involved (about $24 million).
Since that time SCE has studied other less costly options. Four are shown in the Attachment No. 2. Alternatives C and D in the attachment are the options favored. Alternative C would involve adding a new feedwater pump dedicated only to feedwater; the existing feedwater/SI pump would be changed to a dedicated SI pump, aligned permanently for safety injection. Alternative D would involve enhancements to the charging system and piping/valving changes to the safety injection system. Alternative 0 was discussed in the most detail and was favored by SCE. The NRC staff had no unfavorable comments at this proposal stage. SCE will provide a submittal in April 1988 and plans to implement the enhancements by the cycle XI refueling outage, Summer 1990.
original signed by Charles Trammell Charles M. Trammell, Project Manager Project Directorate V Division of Reactor Projects -
- III, IV, V and Special Projects Attachments:
- 1. Attendees
- 2. Handouts cc:
See next page Distribution DocTetF e GKnighton NRC & Local PDRs CTrammell PD5 Reading OGC-Bethesda DCrutchfield EJordan GHolahan JPartlow 0
5 DRSP/D:PD5 ammell:vt GWKnighton 8804290114 88)422f PDR ADOCK 05000206 I~o~
8 REGq UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 April 22, 1988 Docket Nos.: 50-206 LICENSEE:
SOUTHERN CALIFORNIA EDISON COMPANY FACILITY:
SAN ONOFRE NUCLEAR GENERATING STATION, UNIT NO. 1
SUBJECT:
SUMMARY
OF MEETING HELD ON MARCH 16, 1988 REGARDING PROPOSED IMPROVEMENTS TO THE SAFETY INJECTION SYSTEM - SAN ONOFRE UNIT 1 On March 16, 1988, the NRC staff met with representatives of Southern California Edison (SCE) to discuss alternatives to improving the Safety Injection System (SIS) at San Onofre Unit No. 1. Attendees are listed in Attachment No. 1. Handout material presented at the meeting is shown in Attachment No. 2. The meeting was held pursuant to notice dated March 9, 1988.
SCE originally proposed to add a fully qualified dedicated SIS but, on the strength of a detailed probability risk assessment (PRA), concluded that such a system would not provide enhancements in core damage risks commensurate with the costs involved (about $24 million).
Since that time SCE has studied other less costly options. Four are shown in the Attachment No. 2. Alternatives C and D in the attachment are the options favored. Alternative C would involve adding a new feedwater pump dedicated only to feedwater; the existing feedwater/SI pump would be changed to a dedicated SI pump, aligned permanently for safety injection. Alternative D would involve enhancements to the charging system and piping/valving changes to the safety injection system. Alternative D was discussed in the most detail and was favored by SCE. The NRC staff had no unfavorable comments at this proposal stage. SCE will provide a submittal in April 1988 and plans to implement the enhancements by the cycle XI refueling outage, Summer 1990.
Charles M. Trammell, Project Manager Project Directorate V Division of Reactor Projects -
- III, IV, V and Special Projects Attachments:
- 1. Attendees
- 2. Handouts cc:
See next page
Mr. Kenneth P.' Baskin San Onofre Nuclear Generating Southern California Edison Company Station, Unit No. 1 cc Charles R. Kocher, Assistant Mr. Jack McGurk, Acting Chief General Counsel Radiological Health Branch James Beoletto, Esquire State Department of Health Southern California Edison Company Services Post Office Box 800 714 P Street, Office Bldg. 8 Rosemead, California 91770 Sacramento, California 95814 David R. Pi-gott Mr. Hans Kaspar, Executive Director Orrick, Herrington & Sutcliffe Marine Review Committee, Inc.
600 Montgomery Street 531 Encinitas Boulevard, Suite 105 San Francisco, California 94111 Encinitas, California 92024 Mr. Robert G. Lacy Mr. Dennis M. Smith, Chief Manager, Nuclear Radiological Programs Division San Diego Gas & Electric Company Governor's Office of Emergency Svcs.
P. 0. Box 1831 State of California San Diego, California 92112 2800 Meadowview Road Sacramento, California 95832 Resident Inspector/San Onofre NPS U.S. NRC P. 0. Box 4329 San Clemente, California 92672, Mayor City of San Clemente San Clemente, California 92672 Chairman Board of Supervisors County of San Diego San Diego, California 92101 Director Energy Facilities Siting Division Energy Resources Conservation &
Development Commission 1516 - 9th Street Sacramento, California 95814 Regional Administrator, Region V U.S. Nuclear Regulatory Commission 1450 Maria Lane, Suite 210 Walnut Creek, California 94596
Attachment No. 1 ATTENDEES MARCH 16, 1988 MEETING NRC SCE C. Trammell J. Rainsberry S. Rhow D. Pilmer C. Liang K. Baskin G. Knighton M. Medford G. Hsii D. Crutchfield G. Holahan
Safety Injection System Improvement Alternatives San Onofre Unit 1 Agenda I. Introduction II. Improvement Alternatives A. New Safety Related Safety Injection Train B. New Non-Safety Related Safety Injection Train C. New Non-Safety Related Feedwater Pump D. Enhanced Charging/Safety Injection Bypass III. Selection Considerations A. Probability Risk Assessment B. Design Considerations C. Cost IV. Analysis Results V. Schedule Considerations
SAFETY INJECTION SYSTEM SAN ONOFRE UNIT 1 CONTAINMENT P
OUTSIDE INSIDE SAFETY H
INJECTION.PUMPS91 PUMPS PUMPS HV-853A TO LOOP C G-343 COLD LEG F M -(
G-34 G-50A (EAST)
HV-854A HV-852A FT M
SIS PUMP TO LOOP B RECIRC FROM TO COLDLEG CONDENSATE FEEDWATER PUMPS SYSTEM MOV-850B HV-854B HV-852B FT M
MOOO4 H
MOV-850A HV-8548 -jI7 HV-851 B HV-853B HV-851B0 G-3B-G-50B (WEST)
FROM CHARGING SYSTEM
G-500 G-50CSI 800STER PUMP NEW 3RD TRAIN OF SAFETY INJECTION FROM EXISTING SAFETY NTO REACTOR INJECTION SYSTEM VN-COOLANT SYSTEM ALTERNATIVE A NEW SAFETY RELATED SAFETY INJECTION TRAIN
G-500 SIEPP SI BOOSTER PUMP NE NONSNE 3RD TRAIN OF SAFETY INJECTION FROM EXISTING SAFETY TOLATO INJECTION SYSTEM' COOLT ALTERNATIVE B NEW NON-SAFETY RELATED SAFETY INJECTION TRAIN
NEW DEDICATED FEEDPATER PUmp N 2HATER 854 TO 1ST POINT G-3B FEEDMATER PUMP (WEST)
HY 853 B V85 FROM SI PUMP TO RCS TO RCS ALTERNATIVE C NEW NON-SAFETY RELATED FEEDHATER PUMP
RWST VOLUME CONTROL TANK N 2 FCV-lll112 NDV 1100 C CHARGING TO LOOP A NOV 1100 D
NOV 1100 G-88
_O 1115 E LOC LOO
TO R ALTERNATIVE D s IPMPENHANCED IA PIA CHARGING/SAFETY INJECTION BYPASS
Probabi ic Risk Assessment Results Safety Injection System Improvement Alternatives Break Size Annual Probability of Core Melt Existing Plant New Non-Safety Enhanced Charging/
Related Feedwater Safety Injection Pump Bypass Large LOCA 4.2 x 10-7 3.2 x 10-7 2.2 x 10-7 (Break >6")
Medium LOCA 9.4 x 10-7 7.3 x 10-7 2.8 x 10-8 (3"<Break<6")
Small LOCA 6.2 x 10-6 4.2 x 10-6 5.5 x 10-6 (3/8"<Break<3")
Total 7.6 x 10-6 5.3 x 10-6 5.7 x 10-6
Probabilistic Risk Assessment Results Safety Injection System Improvement Alternatives Probability of Failure of Safety Injection Valves /
Total Annual Probability of Core Melt
/
Existing Plant New Non-Safety Enhanced Charging/
Related Feedwater Safety Injection Pump Bypass 3 x 10-3 7.6 x 10-6 5.3 x 10-6 5.7 x 10-6 1 x 10-2 8.2 x 10-6 5.6 x 10-6 5.8 x 10-6 5 x 10-2 1.5 x 10-5 6.8 x 10-6 5.8 x 10- 6 0849P
Safety Injection System Improvement Alternatives Design Considerations New Non-Safety Related Enhanced Charging/Safety Feedwater Pump Injection Bypass Improves 1 train of low pressure/
Improves both high pressure/low flow safety injection and low pressure/high flow safety injection Adds 3500hp load to Bus 1B Minimal effect on electrical system No affect on recirculation Reduces manual actions for recirculation Makes safety injection, feedwater All system trains remain similar and electrical trains dissimilar
Safety Injection System Improvement Alternatives cost New Non-Safety Related Feedwater Pump
$8.4 million Enhanced Charging/Safety Injection Bypass
$7.8 -
8.8 million
Safety Injection System Improvement Alternatives Analysis Results
VOLUE CONTROL TANK NDv 1100 C fcv-1112 Nov 1100 f CNARIMSG TO LOOP A FCV 1115 D3 NOV 100 0 Nov 19
~
-t01
- ooc
- SI ICIAI FROM SELIJ(W2[n S111 F
MV 854 6-3O F ~ J NI T O85 2
, FEElalATM paga NU 853 Now. 851*
FRONf SI Ptwgs To acs ALTERNATIVE D ENHANCED CHARGING/SAFETY INJECTION BYPASS
3-LOOP PLANT CHARACTERISTICS Generic 3-Loop SONGS 1 Core Power (MWT) 2652 1347 Number of Coolant Loops 3
3 Peak Linear Power (kw/ft) 12.2 13.7 Total Peaking Factor 2.32 2.89 Fuel Array 17x17 14x14 Number of Fuel Assemblies 157 157 Core Length (ft) 12 10 Accumulator Water Volume (ft3) 1025 Fuel Cladding Material Zircaloy Stainless Steel RCS Volume (ft )
9190 6940 SG Safety Valve Setpoint (psia) 1174 985
SAFETY INJECTION SYSTEM DELIVERY CURVES SAN ONOFRE UNIT 1 2800 2600 U
0-CHARGING + SAFETY INJECTION PUMPS 2200 EXISTING SAFETY INJECTION SYSTEM 2000 GENERIC 3-LOOP PLANT h
1800 Li 1600 1400 Li 1200 1000 800 -I 600 400 200 oI I[
O 100 200 300 400 500 600 700 800 PUMP FLOW (LB/SEC)
I'
~ ~
~
l' I V:
- !II:
1k; I,
Ii IN
.0 oil 1 1 V~~
i
- 1.
F il pill
/l0 1h
?<L% r29q
LARGE BREAK LOCA SI MOD ALTERNATE D PLANT PERFORMANCE EVALUATION Alternative D Existing System (2 SI Pumps + 2 Chg Pumps)
(1 MFW/SI Pump)
Flow @ 50 psia 650 lb/sec 700 lb/sec (584 SI)
( 66 Chg)
SI Delay Time (sec) 17.3 (No LOP) 26.9 (LOP)
(Pumps, Valves, Line Fill)
Free Fall Time (sec) 0.9 0.9 (Nozzle to Lower Plenum)
Lower Plenum Refill Time (sec) 45.2 42.0 Core Refill to 1-1/2' Level (sec) 10.0 9.3 Total (sec) 73.4 79.1 PCT (OF) 2192 2272
SONGS 1 SBLOCA WITH EXISTING SI SYSTEM COMPARISON OF RETRAN AND WFLASH
SONGS 1 SBLOCA EXISTING SI SYSTEM 6 INCH BREAK MIXTURE LEVEL FROM TOP OF ACTIVE CORE 10 a
-8 Ll 6
-2 LJ
-2
-8
-10 0
20 40 80 80 100 120 140 160 180 200 TIME (SEC)
70.000 SCE SMALL BA(AK ANALYSIS Sil INCH BREAK CORE MIXTURE LEVEL (ill II.500 15.000 12I.500 10.000 a
l.5j00 m
5.0000
?. 5000 0.0 TIME tISCI
SONGS 1 SBLOCA EXISTING SI SYSTEM 6 INCH BREAK BREAK FLOW AND SI FLOW 3600.
BREAK FLOW C30
-SI FLOW 3200W m
2800 2400 2000 1600 Cl) 800~I 00 0
20 40 60 80 100 120 140 180 180 200 TIME (SEC)
RETRAN Analysis of SBLOCA with Modified SI
SONGS1 SBLOCA UPGRADE SI SYSTEM 6 INCH BREAK MIXTURE LEVEL FROM TOP OF CORE 10..................................
8 6
L-4
-2 S -6
-8
- 1 0 0
50 100 150 200 250 300 350 400 TI ME (S EC)
SONGS1 SBLOCA WITH SI SYSTEM UPGRADE 6 INCH BREAK SI FLOW AND BREAK FLOW 4500 4000:
.--- BREAK FLOW soo.5 SI FLOW
~3000 2500 2000 121500 :
10001 500 0
50 100 150 200 250 300 350 400 TIME (SEC)
SAFETY INJECTION AND CORE FLOW VS.
TIME SAN ONOFRE UNIT 1 125 SONGS-1 SI FLOW GENERIC SI FLOW SONGS-1 CORE FLOW 100 GENERIC CORE FLOW '
cV)
Lii 75 50 25 j
0 I
I 0
500 1000 1500 2000 2500 3000 TIME (SECONDS)
Safety Injection System Improvement Alternatives Schedule Considerations for Enhanced Charging/Safety Injection Bypass Plan to Implement During Cycle XI Refueling Outage (A Mqq Effect on Integrated Implementation Schedule Schedule B items deferred to Cycle XII Outage:
Control Room HVAC Seismic Qualification of Electrical Equipment Modifications In Service Testing Modifications Diesel Generator Slow Start Modifications Control Room Design Review Modifications 0851P