ML13308B795
| ML13308B795 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 11/06/1980 |
| From: | Curran J, Morgan H SOUTH CAROLINA ELECTRIC & GAS CO., SOUTHERN CALIFORNIA EDISON CO. |
| To: | |
| Shared Package | |
| ML13308B793 | List: |
| References | |
| SO23-3-5.29, NUDOCS 8011250482 | |
| Download: ML13308B795 (11) | |
Text
SAN ONOFRE NUCLEAR GENERATING STATION OPERATING INSTRUCTION S023-3-5.29 UNITS 2 AND 3 EMERGENCY Page 1 NEW Nov 6 1980 STEAM GENERATOR TUBE RUPTURE 1.0 SYMPTOMS 1.1 Alarms 1.1.1 Steam Generator Blowdown Monitor.
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,*7 1.1.2 Condenser Air Ejector Airborne Radiation Hi.
R 1.1.3 Main Steam Line Radiation Hi.
7 U
1.1.4 Pressurizer Pressure Level Error Lo.
EDVs71980 1.1.5 Pressurizer Pressure Deviation Hi/Lo.
-SITE 1.1.6 Volume Control Tank T077 Level Hi/Lo.
1.2 Indications 1.2.1 Increased radiation levels in main steam line radiation mon itor in control room.
1.2.2 Increased activity in the steam generator blowdowm sample radioactivity monitor's RI-6753 and RI-6579 on Pnl L27, Tur bine Plant Sample Rack.
1.2.3 Increasing activity at the condenser air ejector exhaust on RI-7818 at Pnl L-103.
1.2.4 Decreasing prpssurizer level.
1.2.5 Initial increase in affected steam generator level followed by return to programmed level setpoint (may not be observable).
1.2.6 Feedwater flow less than steam on affected steam gen erator (may not be observable).
1.2.7 Unbalanced charging and letdown flows.
1.2.8 Increasing activity and presence of boric acid in steam gen erator samples.
SSEDSON
SAN ONOFRE NUCLEAR GENERATING STATION OPERATING INSTRUCTION S023-3-5.29 UNITS 2 AND 3 EMERGENCY Page 2 NEW 1.0 SYMPTOMS (Continued) 1.2 Indications (Continued)
NOTE:
A Steam Generator Tube Failure causes leakage of reactor coolant into the steam system. If the leak age exceeds the capacity of the Pressurizer Level Control System (charging minus letdown), pressurizer pressure will decrease rapidly, causing a DNBR trip.
The subsequent cooldown following the reactor trip combined with the continued leakage of reactor coolant into the Steam Generator will cause a further reduc tion in pressurizer pressure and level, resulting in initiation of safety injection and containment iso lation. The tube rupture will cause a reduction in reactor coolant system volume and due to reactor coolant leakage into the steam generator, the affected steam generator level will continue to increase after the feedwater block valves are isolated. The resulting decrease in RCS pressure and volume will result in the RCS reaching saturation conditions. The pos sibility then exists for void formation in the re actor coolant system.
NOTE:
Operator action should be directed toward prompt isolation of the affected Steam Generator, to min imize. contamination of the steam system and prevent possible radioactive release to the environment. With the exception of a compound accident in which loss of power accompanies the Steam Generator Tube failure, steam is dumped to the condenser, rather than the atmosphere, to prevent gross release of contamination to the environment. Action must be taken to identify the affected Steam Generator as soon as possible and to isolate its feedwater flow to prevent water slugging the steam lines.
2.0 AUTOMATIC ACTION 2.1 A steam generator blowdown monitor will activate a high radiation alarm in the control room and signals to trip close the blowdown processing system neutralization sump overboard valve.
2.2 Reactor trip, if pressurizer pressure decreases to the DNBR setpoint.
00 SAN ONOFRE NUCLEAR GENERATING STATION OPERATING INSTRUCTION S023-3-5.29 UNITS 2 AND 3 EMERGENCY Page 3 NEW 2.0 AUTOMATIC ACTION (Continued) 2.3 Letdown control valves close to a minimum value and backup charging pumps are started as pressurize level decreases.
2.4 Initiation of safety injection and containment isolation, if pressurizer pressure decreases to below 1806 psia.
2.5 Makeup to Volume Control Tank, if in automatic.
2.6 The feedwater regulating system may reduce the feedwater flow to the affected steam generator to maintain acceptable steam generator levels.
2.7 Turbine trip (if reactor trip).
3.0 IMMEDIATE OPERATOR ACTION 3.1 If pressurizer level is being maintained by the pressurizer level control system:
3.1.1 Reduce turbine load at a maximum rate which will not cause a reactor trip.
3.1.2 Verify the CVCS is functioning to restore pressurizer level.
If necessary, start additional charging pumps and isolate let down line to restore pressurizer level.
3.1.3 Verify the pressurizer pressure control, system is automatically maintaining pressurizer pressure. If not, manually control pressurizer pressure.
3.1.4 Commence a reactor shutdown by CEA insertion or emergency boration.
3.1.5 Isolate steam generator blowdown by closing the blowdown iso lation valves.
3.1.6 With "Condenser Air Ejector Airborne Radiation Hi" alarm, place the air ejector exhaust unit in the "direct" mode of service.
3.1.7 Verify the feedwater control system is maintainino - 65% steam generator level.
If not, take manual control of the feedwater control system and maintain ' 65% narrow range level.
3.1.8 Check containment pressure, radiation and sump level as normal, to verify the event in progress is not a LOCA.
SAN ONOFRE NUCLEAR GENERATINGSTATION OPERATING INSTRUCTION S023-3-5.29 UNITS 2 AND 3 EMERGENCY Page 4 NEW 3.0 IMMEDIATE OPERATOR ACTION (Continued) 3.2 If pressurizer level cannot be maintained by the pressurizer level con trol system:
3.2.1 If reactor has not tripped, manually trip the reactor and verify reactor power decreasing.
3.2.2 Verify the turbine tripped. If not, manually trip the turbine.
3.2.3 Verify the unit output breakers are open. If not, manually trip the unit output breakers. Verify turbine speed is de creasing.
3.2.4 Verify the unit auxiliaries have transfered to the reserve auxiliary transformers. If not, manually transfer to reserve auxiliary transformers.
3.2.5 If pressurizer pressure drops below 1806 psia and SIAS, CIAS and CCAS have not automatically initiated, manually initiate them and verify properly activiated.
3.2.6 After a SIAS due to low pressurizer pressure, and as soon as possible after it has been verified that all CEA's have been fully inserted for at least five (5) seconds, stop all oper ating reactor coolant pumps.
3.2.7 Isolate steam generator blowdown by closing the blowdown isolation valves.
3.2.8 Check containment pressure, radiation and sump level as normal to verify the event in progress is not a LOCA.
4.0 SUBSEQUENT OPERATOR ACTION 4.1 After any SIAS, operate the SIS until RCS hot and cold leg temper atures are at least 50aF below saturation temperature for the RCS pressure and a pressurizer level greater than 28% and increasing is indicated, unless the cause of the SIAS has been verified to be an inadvertant actuation. If 50'F subcooling cannot be maintained after the system has been stopped, the high pressure injection system must be restarted.
SAN ONOFRE NUCLEAR GENERATING STATION OPERATING INSTRUCTION S023-3-5.29 UNITS 2 AND 3 EMERGENCY Page 5 NEW 4.0 SUBSEQUENT OPERATOR ACTION (Continued) 4.1 (Continued) 4.1.1 Refer to Operating Instruction S023-3-2.7, "Safety Injection System Operation".
4.1.2 If advertent SIAS, refer to Emergency Operating Instruction S023-3-5.15, "Recovery from Inadvertent Safety Injection".
4.2 If all RCP's are stopped, verify that natural circulation has been es tablished per Operating Instruction S023-3-2.31, "Natural Circulation Guidelines 4.3 Control feedwater flow to maintain steam generator narrow range levels at - 65%.
4.3.1 If EFAS 1 or EFAS 2 has been activiated, verify the avail ability of the electric motor driven pumps, then override and stop the steam driven pump.
4.3.2 If main feedwater flow is being used, place the electric driven auxiliary feedwater pumps in service. Refer to Operating In struction S023-2-4, "Auxiliary Feedwater Pump Operation".
4.3.3 Secure main feedwater after the reactor has been tripped or shutdown, if the auxiliary feedwater supply to each steam generator is available.
4.4 Determine which steam generator has the tube rupture by:
4.4.1 Checking main steam line radiation monitors for increased activity.
4.4.2 Checking steam generator blowdown sample radioactivity mon itors RI-6753 and RI-6754 on PNL 2/3 L-27, Turbine Plant Sample Rack.
4.4.3 Sampling steam generators for increased activity and presence of boron.
4.4.4 Possible unexplained changes in steam generator level on steam generator level recorders.
4.4.5 Possible unexplained decrease in steam generator feedwater flow as compared to steam flow on steam flow/feedflow recorders.
SAN ONOFRE NUCLEAR GENERATING STATION OPERATING INSTRUCTION 5023-3-5.29 UNITS 2 AND 3 EMERGENCY Page 6 NEW 4.0 SUBSEQUENT OPERATOR ACTION (Continued) 4.4.6 If the affected steam generator has not been identified by the above methods, use the level rise method contained in Step 4.6.
NOTE:
Do not isolate the steam generator until hot leg temperatures are less than 545 0F.
4.5 The Watch Engineer shall notify the "duty" Station Administrator and Shift Technical Advisor and discuss the situation. An assessment of plant status and safety shall be made and the event classified. If an emergency is declared (Alert, Site or General), the Emergency Plan will be actuated using the implementing Emergency Procedures.
If unable to contact any Station Administrator in the normal reporting chain within fifteen (15) minutes following the declared emergency, notify the NRC via the red phone.
4.5.1 For implementing the Radiological Emergency Plan, refer to Station Emergency Procedure 5023-VIII-1.3, "Unit Emergency".
4.5.2 Refer to Operating Instruction S023-3-2.30, "Determination of Adequate Core Cooling", to verify core cooling.
4.5.3 Notify Systems Operating Supervisor concerning the nature of the emergency.
4.6 Cooldown the RCS until hot leg temperatures are below 545 0F.
4.6.1 If the SBCS is available, match the local setpoint with the existing pressure, then switch to local setpoint. Lower the local setpoint to -- 950 psia.
4.6.2 If the SBCS is not available, use the atmospheric steam dump on the unaffected steam generator.
.1 If the affected steam generator has not been identified, and the SBCS is not available, cooldown the RCS using the atmospheric steam dump on the unsuspected steam generator.
4.6.3 Isolate the affected or suspected steam generator.
.1 Close the affected steam generator's main steam isolation valve HV-8204 (E089-S) or HV-8205 (EO88-N).
.2 Verify closed or close the affected steam generator's main steam isolation bypass valve, HV-8202 (E089-S) or HV-8203 (E088-N).
SAN ONOFRE NUCLEAR GENERATING STATION OPERATING INSTRUCTION 5023-3-5.29 UNITS 2 AND 3 EMERGENCY Page 7 NEW 4.0 SUBSEQUENT OPERATOR ACTION (Continued) 4.6.3.3 Isolate feedwater to the affected steam generator. Close HV-4048 (EO88-N) or HV-4052 (EO89-S) main feedwater iso lation valve. If using auxiliary feedwater, close HV-4715 and HV-4731 (EO88-N) or HV-4714 and HV-4730 (E089-S).
NOTE:
If the suspected steam generator has been isolated, observe level indicator. The level in the affected steam generator will continue to rise even after isolation, due to the leak.
4.7 Commence RCS cooldown and depressurization as quickly as possible. Do not exceed a cooldown rate of 750F/hr.
4.7.1 Use the SBCS, if available, and cooldown per Operating In struction S023-5-1.5, "Plant Shutdown From Hot Standby to Cold".
4.7.2 If the SBCS is not available, use the atmospheric steam dump on the unaffected steam generator.
4.7.3 If the RCP's have been tripped, cooldown using natural circu lation. Refer to Operating Instruction S023-3-2.31, "Natural Circulation Guidelines".
4.7.4 Using pressurizer heaters and sprays establish and maintain 50'F subcooling in the RCS utilizing the subcooling margin monitor with TH, pressurizer pressure, pressurizer temperature and incore thermocouple to determine the margin to saturation.
4.7.5 Once T is below 490'F, pressurizer pressure can be reduced below O psia, which should bring steam generator tube leakage to a minimum. Maintain RCS pressure -.
50 psi above the affected steam generator pressure to prevent RCS dilution.
4.8 After isolation of the affected steam generator, and during cooldown, maintain RCS pressure greater than the affected steam generator pres sure to prevent dilution of the RCS, by one the following means:
4.8.1 Take manual control of pressurizer pressure and using sprays and heaters, if required, control pressure during cooldown.
.1 If a RCP is not operating in Loop 1, or offsite power is not available, use the auxiliary sprays to control pressure.
SAN ONOFRE NUCLEAR GENERATING STATION OPERATING INSTRUCTION S023-3-5.29 UNITS 2 AND 3 EMERGENCY Page 8 NEW 4.0 SUBSEQUENT OPERATOR ACTION (Continued) 4.8.2 Throttle HPSI pump discharge valves and use auxiliary spray, if required, to control pressure. Maintain pressurizer level between 28% and 57%.
CAUTION:
If SIAS has occured, do not throttle or secure HPSI flow, unless at least 50aF subcooling can be main tained in the RCS, cold leg temperature is stable, or decreasing, and there is level indicated in the pressurizer between 28% and 57%.
4.9 Close LV-3245, condenser draw off valve and redirect turbine sumps by closing HV-5849, discharge to only waste sump, and opening HV5850, discharge to radwaste sump.
4.10 If a SIAS was activiated, terminate RCS charging within thirty (30) minutes.
4.10.1 Override and stop the charging pumps and the boric acid make up pumps.
4.10.2 When the SIAS is reset, and if offsite power is available, establish normal charging and letdown per Operating Instruction S023-3-2.1, "CVCS Charging and Letdown" and S023-3-2.2, "Makeup Operations".
.1 If offsite power is not available, line up charging pump suction to gravity feed from the RWST to maintain pressurizer level.
.1.1 Open LV-0277C, gravity feed valve from RWST.
.1.2 Verify closed or close the following: LV-0227B, VCT discharge HV-9247, BAMU pump discharge to charging pump suction, HV-9235 and HV-9240, BAMT gravity feed to charging pump suction.
4.11 If SIAS was actuated, and if RCS hot and cold leg temperatures are at least 50'F below saturation for the corresponding RCS pressure and a pressurizer level of at least 28% and increasing is indicated, reset SIAS.
4.11.1 Reset SIAS at the Plant Protection Panels and Auxiliary Relay Cabinets.
.1 Stop LPSI, HPSI and containment spray pumps.
NOTE:
If 50'F subcooling cannot be maintained, restart the high pressure safety injection pumps.
SAN ONOFRE NUCLEAR GENERATING STATION OPERATING INSTRUCTION S023-3-5.29 UNITS 2 AND 3 EMERGENCY Page 9 NEW 4.0 SUBSEQUENT OPERATOR ACTION (Continued) 4.12 If RCP's were stopped, if possible, restart the RCP's.in the unaffected loop per Operating Instruction S023-3-1.7, "RCP Operation".
4.12.1 The following criteria must be satisfied before restarting RCP's.
- 1. A LOCA does not exist;
- 2. RCS temperature and pressure conditions permit restart;
- 3. RCP services are available.
4.12.2 If a RCP is restarted, continue cooldown per Operating Instruction S023-5-1.5, "Plant Shutdown From Hot Standby to Cold".
4.12.3 If the RCP's cannot be restarted, maintain natural circulation conditions per Operating Instruction S023-3-2.31, "Natural Circulation Guidelines".
4.13 During cooldown, maintain level in the affected steam generator at ". 30%
(narrow range), by one of the following means:
CAUTION: While cooling and maintaining steam generator level, maintain RCS pressure greater than the pressure in the affected steam generator to prevent dilution of the RCS.
4.13.1 If sufficient storage capacity exist in the miscellaneous rad waste storage system, bleed and feed the affected steam gen erator using the steam generator blowdown processing system and auxiliary feedwater system. Refer to Operating Instruction S023-9-4, "Steam Generator Blowdown Processing System Oper ation" with the following exceptions:
.1 Step 6.1.5, the flash tank must be aligned to the condenser by placing control switch HS-4084 to the "CONDENSER" position.
.2 Step 6.1.9, align neutralization sump discharge to chemical waste tank T-064 per Operating Instruction S023-9-4.1 Step 6.2.7, "Blowdown Processing Demineralizer Operation".
.3 Establish radiation control areas in the area of blow down processing system to minimize personnel exposure to surface contamination, radiation and airborne contamination.
.4 Initiate auxiliary feedwater to the affected steam generator per Operating Instruction S023-2-4.0, "Auxiliary Feedwater Pump Operation".
.5 When both systems are aligned, maintain a level of approxi mately 30% (narrow range) in the affected steam generator by feeding with auxiliary feedwater and bleeding down to the blowdown processing system.
SAN ONOFRE NUCLEAR GENERATING STATION OPERATING INSTRUCTION 5023-3-5.29 UNITS 2 AND 3 EMERGENCY Page 10 NEW 4.0 SUBSEQUENT OPERATOR ACTION (Continued) 4.13.2 If offsite power is not available, or the blowdown processing system is unavailable, allow the level to rise in the affected steam generator while continuing natural circulation cooldown.
.1 If the affected steam generator approaches 90% narrow range level, lower RCS pressure and allow the steam generator in ventory to backflow into the RCS.
CAUTION:
Stop the pressure decrease if void formation occurs in the affected steam generator loop as indicated by pressurizer level increase.
.1.1 Sample the RCS for boron concentration once every hour. Borate as required to maintain the required shutdown margin.
.1.2 Initiate auxiliary feedwater to the affected steam generator per Operating Instruction S023-2-4.0, "Auxiliary Feedwater Pump Operation", and maintain steam generator level at ' 30%
(narrow range).
.1.3 Reduce RCS pressure below the affected steam generator pres sure to begin draining the affected steam generator.
CAUTION:
Maintain 50'F subcooling the RCS when reducing RCS pressure.
4.14 Verify effective isolation of the affected steam generator by com pleting the following:
4.14.1 Shutdown all turbine building ventilation.
4.14.2 Sample the condensate system to determine activity levels during cooldown and after the cooldown.
4.14.3 Take air particulate and air gaseous samples in the area of the air ejector after condenser and gland steam condenser combined vent.
4.14.4 Take local area and offsite surveys for indications of un usually high radiation or airborne levels.
4.14.5 Establish radiation control areas to minimize personnel ex posure to surface contamination, radiation and airborne contamination.
SAN ONOFRE NUCLEAR GENERATING STATION OPERATING INSTRUCTION 5023-3-5.29 UNITS 2 AND 3 EMERGENCY Page 11 NEW 4.0 SUBSEQUENT OPERATOR ACTION (Continued) 4.14.6 Sample turbine building sumps for any increased activity.
4.14.7 Monitor steam generator blowdown sample activity on RI-6759 and RI-6753 at PNL L-27.
4.14.8 Use control room indication to monitor steam generator main steam piping for increased activity.
4.14.9 Monitor condenser air ejector exhaust on RI-7818 at PNL L-103.
4.15 If a radioactive release in excess of Technical Specifications is occuring or is suspected, declare the emergency (Alert, Site or General) and implement the Radiological Emergency Plan including appropriate notifi cation of offsite authorities.
4.16 Verify reactor shutdown margin and insure that reactor is > 5.15% & k/k shutdown per plant monitoring system or Operating Instruction 5023-3-3.29, "Determination of Shutdown Margin".
4.16.1 If shutdown margin is less than required, commence emergency boration.
4.17 If the transient has stabilized and ESF Busses are being supplied from offsite power, stop the emergency diesel generators. Refer to Operating Instruction S023-2-13.0, "Diesel Generator Operation".
4.18 If the SIAS/CIAS has been reset, return the safety injection system and containment isolation system to normal per Operating Instruction S023 3-2.7, "Safety Injection System Operation".
4.19 When the plant is cooled and depressurized to 350aF and 361 psig, initiate shutdown cooling. Refer to Operating Instruction S023-3-2.6, "Shutdown Cooling System Operation".
H. E. MORGAN SUPERINTENDENT UNITS 2 AND 3 APPROVED:
M C!URRAN PLANT MANAGER MT/sa