ML13333A405
| ML13333A405 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 08/31/1979 |
| From: | Haynes J SOUTHERN CALIFORNIA EDISON CO. |
| To: | Ziemann D Office of Nuclear Reactor Regulation |
| References | |
| TASK-05-13, TASK-5-13, TASK-RR NUDOCS 7909110455 | |
| Download: ML13333A405 (19) | |
Text
Southern California Edison Company P. 0.
BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD. CALIFORNIA 91770 August 31, 1979 Director of Nuclear Reactor Regulation Attention:
Mr. D. L. Ziemann, Chief Operating Reactors Branch #2 Division of Operating Reactors U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Gentlemen:
Subject:
Information Requested Concerning Steam Generator Water Hammer San Onofre Nuclear Generating Station Unit 1 Enclosed is SCE's response to a set of questions telecopied to us on August 2, 1979 concerning the susceptability of San Onofre Unit 1 to steam generator water hammer. A copy of this letter is also being sent to Mr. Dwight Christiansen at EG&G.
If you have any questions on this information, please let us know.
Very truly yours, J. G. Haynes Chief of Nuclear Engineering Enclosure cc:
D. Christiansen (EG&G Idaho)
Information Concerning Susceptability to Steam Generator Water Hammer August 29, 1979 What is the effect of safety injection capability on the operation of the main feedwater system during normal and hypothetical accident conditions?
In the event of a safety injection actuation signal the normal feedwaterp...
suction and discharge valves (hVs 654A, 654B, 852A and 852B) close and the valves in the safety injection train (HVs 853A, 853B, 851A and 8513) open.
During safety injection service the feedwater pumps cannot be used to feed the steam generators.
During low power, startup, and hot shutdown conditions, describe feedwater control and utilization of feedwater bypass lines (if any), auxiliary-feedwater system, condensate pumps, and main feedwater system.
A. Describe main feedwater control (auto and manual) following a reactor trip from full power without feedwater isolation.
Response
Feedwater control during low power, startup and hot shutdown conJitions is described in Operating Instruction S-3-2.27, Feedwater Control Mode Transfer and Operations (copy attached). Additional information can also be found in Operating Instruction S-3-1.1, Plant Startup From Cold Conditions to Minimum Load (copy attached).
Following a reactor trip there is no feedwater isolation. If Tave is greater than 5450 F, the automatic steam generator level control remains in service and maintains steam generator level at the 30% narrow range level setpoint. If Tave is less than 5450F, the main feedwater regulator valves close to contol feedwater flow at 5$ of full load feedwater flow. In either case manual override is possible.
Item 3 Can the main feedwater pumps trip independently of each other?
Response
The main feedwater pumps can trip independently of each other.
M/
-2 Length of main feedwater piping fron outside surface of each steam generator to the first downward turning elbow?
Res2onse As described in our December 27, 1977 letter to Mr. Schwencer of the IHC, the horizontal lengths of feedwater piping from the steam generator nozzles to the centerline of the downward sloping 450 ells are 31 3/14" on steam generators A and C and 19 1/14" on steam generator B.
Item 5 Feedwater flow limitation during refill of steam generators following events that resulted in feedring uncovery?
Response
Operating Instruction S-3-2.27 includes a precautionary statement which instructs the operators to reestablisn feedwater flow slowly to avoid water hammer.
Item 6 Describe pertinent plant conditions (such as, steam generator levels, feedwater flows, duration of feedring uncovery, etc.) that existed before and during all steam generator water hammers that have occurred.
Response
There have been three reported incidents of water hammer at San Onofre Unit 1.
Two of these were described in our July 14, 1975 and December 27, 1977 letters to the NRC and the third was described in our July 3, 1979 letter to the NRhC.
A discussion of information available on plant conditions during eacn incident is provided below. Flow metering capability for low flow conditions is not available.
- 1. water hammer was observed on April 29, 1972 as a result of failure of the valve positioner on one of the main feedwater regulator valves.
During this event, steam generator level decreased to a minimum of 17% on the narrow range.
The maximum time'that the feedring was uncovered (level below 26) was 14 minutes.
Feedwater flow before or during the water, hammer is not known. No damage to the feedwater line, other than the failed positioner was observed.
- 2. Although no specific water hammer was observed, during a unit shutdown on January 14, 1974, an inspection of the main steam and feedwater line supports revealed that three supports and one snubber were damaged.
-3 Although it was initially speculated that the supports may have been damaged by water hammer, it was subsequently determined that. the supports were improperly designed and installed.
- 3. Water hammer was observed on May 14, 1979.
It is believed that this was due to improper adjustment of the setpoints for closing the feedwater regulator valves following a unit trip.
During this event, steam generator level decreased to 0% on the narrow range. The feedring was uncovered (level below 26%) for about 45 minutes. Feedwater flow before the event was essentially full flow.
Feedwater flow during the event is unknown. After inspection, one of the snubbers on the feedwater li;-wa observed to have a sheared locking nut.
Item 7 List the approximate number of reactor trips, loss of offsite power events, loss of feedwater events, operator error, and any other events resulting in conditions that may have been conducive to steam generator water hammer.
(List the number of events that occurred:
(a) subsequent to final hardware and procedural modifications pertaining to the feedwater system, and (D) suDsequernt and prior to implementation of administrative feedwater flow limits).
Response
A summary of steam generator feedring uncovery incidents (steam generator level less than 26$ on the narrow range) during the period from 1967 to the present is provided as Table 1. This table also includes a summary of tne number of plant outages and reactor trips from all power levels during this same perioo.
There have been two loss of feedwater incidents at San Onofre Unit 1, both of which were the result of safety injection actuation and the suosequent switchover of the feedwater pumps to safety injection service.
These events are included as part of the summary in Table 1. There has never been a loss of offsite power during power operation at San Onofre Unit 1.
Since the plant became operational in 1967 there have been no major modifications to the main feedwater system. Changes were made in operating procedures in 1975 within a few months of shutting the plant down for the year.
The operators were cautioned to attempt to maintain level above the feedring at all times and to add feedwater slowly in the event the feedring did become uncovered.
Further changes in operating procedures were made at the beginning of 1978.
The operators were instructed to maintain steam generator level at 50% when feedwater controls are on manual and load is below 20% and to pay close attention to level when changes are made to the rate of steam generator blowdown.
Item 8 Can the main feedwater pumps take power from the diesel generators during non-safety injection operation?
ResDonse The main feedwater pumps can be connected to the diesel generators during non-safety injection operation.
-5 TABLE 1.
SUMMARY
OF STEAM GENERArOR FEEDRING UNCOVERINGINCIENTS NUMBER OF UNCOVERING INCIDENTS NO.
OF OUTAGES SHUTDOWNS THIPS SCARTUPS YEAR NO, OF OUTAGES W/NO UNCOVERING A
B C
A B
C A
b C
(No. caused Total by trips) 1967 5
(3) 2 1
3 0
1 1
1 0
0 U
1968 8
(2) 2 3
2 1
2 1
2 3
3 1
1969 9
(1)*
1 8
3 5
1 1
1 4
10 8
1970 3
(0) 1 1
2 0
0 0
1 3
1 1971 15 (9) 2 1
2 0
9 9
3 1
7 1972 13 (4) 1 1
6 3
4 4
i 5 20 9
1973 4
(0) 0 3
3 3
0 0
3 2
4 1
1974 8
(2) 3 0
1 0
3 3
3 3
2 5
1975 3
(2) 0 0
0 0
2 2
2 3
6 3
1976 15 (6) 1 6
5 5
6 6
6 13 16 20 1977 7
(4) 0 0
1 0
4 4
4 12 6 16 1978 6
(4) 0 1
2 1
5 5
4 2
3 2
1979**
4 (1) 0 1
2 1
0 1
0 1
2 1
TOTALS 100 38 13 26 32 19 37 37 36 50 83 76
- Actually 2 trips occurred, however the charts were available for only one.
- Through August 23, 1979.
(/O SAN ONOFRE NUCLEQR GENERATING STATION OPERATING INSTRUCTION S-3-1.1 Revision;19 - August 11, 1S73 AUG PLANT STARTYUP FROM COLD CONDITION TO MINIMUM LOAD OBJECTIVE The purpose of this instruction is to provide a safe and ecficier.t method of starting up the plant from a cold shutdown conci:ior tm mini load.
II. CONDITIONS A. All pertinent clearances released and major equipment evaiiVlai for service.
B. The Reactor Coolant System is lined up as follows:
- 1. The Residual Heat Removal System is in service.
- 2. The Reactor Coolant System has been filled and vented ner Operating Instruction S-3-1.6.
C. Charging, Letdown and Seal Water Systems in operation per Operating Instruction S-3-1.10.
III.
PRECAUTIONS A. Steam generator water levels should be manually contr: led at 50>
level as indicated on the narrow range recorders while in hot standby to 20o load to prevent the feedrings from beir: uncovered.
B. At least one reactor coolant pump must be operating wtile chemicals are added to the Reactor Coolant System to obtain thorough mixing.
C. Purification of the letdown flow in the demineralizers should not be initiated during plant startup until oxygen scavenging of the Reactor Coolant System with hydrazine has been completed.
D. Criticality nust be anticipated any time wheno.control rods are being withdrawn or when boron dilution operations are in progress.
E. Any plant changes which produce a sudden change in rea:tor coolant temperature (of the order of 10*F) or in reactor coolant boron concentration (of the order of 10 ppm) must be avoided while the reactor is critical or approaching criticality.
CHECK MPLICABLE CONT I STICK FILE FP CURRENT INF
- O
SAN ONOFRE NUCLEAR jWNERATING STATION OPERATING INSTRUCTION 5-3-1.1 Revision 19 -August 17, 1978 Page 2 F. If at the time criticality is to be achieved, the reacter conditv' are to differ fro. thoe Cor which previous crftical availalble and the differences are such as to cause a char.ge o.
percent a K/K or more in core reactivity, the approach to critcaity must be guided by the available procedure for plotting inverse corn:
rate versus control rod position.
G. The maximum allowable heatup rate for the Reactor Coclart Sy.tc.
60OF per hour.
H. The maximum allowable pressurizer heatup rate is 95'F,er ron.
I. One shutdown group of control rods must be at 220 step.<
whenever positive reactivity is being inserted by be o' dilution, xenon decay, reactor coolant temperature char.es or wit.
drawal of contrzil rods other than the shutdown rod groun. Thn following two exceptions to this rule may be applied:
- 1. The Reactcr Coolant System has been borated to at least the hot, xenon free boron concentration and is being maintained at hot shutdown.
- 2. The Reactor Coolant System has been borated to the cold shutdo,'n boron concentration and the plant is being cooled down.
J. The reactor coolant pressure must be maintained in accordance with the current pressure-temperature curve as the heatup progresses.
Temp.-Press. Points should be plotted every 1/2 hour on the qrapn provided with PSSO-138, unless recorder TR-430,Pressurizer Temperature is in service.
K. The reactor coolant dissolved oxygen level must be 0.1 ppm or less, before the reactor coolant temperature is raised above 250'F.
L. During Reactor Coolant System warmup, the difference in temperature between the pressurizer liquid and the reactor coolant should not be permitted to exceed 200*F.
M. The residual heat removal loop may not be removed fromr service for a prolonged period with irradiated fuel in the reactor vessel until one reactor coolant pump is in service.
N. Place the Safety Injection System in service prior to reducing the reactor shutdown below 4% t K/K, hot, xenon free, all rods in, to limit the consequences of a steam line break.
SAN ONOFRE NUCLEAR GENERATING STATION OPERATING INSTRUCTIO S-3-1.1 Revision 19 - August 17, 1978 Page 3
- 0.
If detectors in more than one power ranye channel ha.
1-r
- 1. The nstrui ent dcpa'rtment will calibrate the a
using simulated detector imputs. The gain contrcs on thec affected channels will be conservatively adjuste: base o7 torical outputs of new detectors.
These settincs shll not be changed until indicated power exceeds 50.
- 2.
A thermal calibration will be performed before te ?S cvN.T.
trip is changed from low to mid-range.
P. Adjust the gain control settings of all power range channell wi have not been modified by detector replacement to pre-hutDown vc ',s.
Q.
Do not maintain pressurizer level above 80% unless re~;red for £w. e cooldown or startup operations.
R. The reactor shall not be made or maintained critical _ress th c. %Iy Injection Systems are operable per Tech. Spec. 3.3.1.
S. The reactor coolant system temperature shall not be i.:rea-sed aovE 200'F. unless the containment spray system, the refueling water storage tank and the associated valves and interlocks are cperable, per Tech. Spec. 3.3.1 and the specific activity of ra ioiodira in te secondary coolant is < 0.1 pCi/gm dose equivalent 1-131.
T. The reactor shall not be made or maintained critical unless the electrical power system is operable per Tech. Spec. 3.7.
U. During the solid water phase of heatup, reactor coolant pumps must be operated continuously, with momentary stops as required by operations, to prevent temperature differences that could result in overpressuriza tion upon reactor coolant pump restart. If all reac::r coolant pumps are stopped, evaluate the possibilities of having developed tempera ture gradients before restarting a reactor coolant pump..
V. Tests or maintenance activities that might affect reactor coolant system pressure shall not be performed during solid system operation.
IV. CHECK-OFF SHEETS See Station Forms listed below.
A. San Onofre Pre-Startup Check-Off List PSSO-136
- 1. Should be completed between Steps 1 and 6 of this Instruction.
B. Reactor Pre-Critical Check-Off List PSSO-137.
- 1. Shall be completed before reactor is critical.
- 2.
Testing of the auxiliary feedwater pump, diesel generators and controls rods shall be completed before the reactor is made critical.
SAN ONOFRE NUCLEAR GENERATING STATION OPERATING INSTRUCTION S-3-1.1 Revision 19-August 17, 1978 Page 4 C. San Onofre Check-Off List for Plant Startup from Cold Conditio.
- 1.
Check-Off items as they are coMrpleted throughout the s trt.
- 2. Testing of the motor driven auxiliary feedw3ter purp must bce co-pleted prior to increasing reactor coolant pressure above D. Turbine Generator Pre-Startup Check-Off List PSSO-236
- 1. Shall be completed before Turbine Roll.
V. INSTRUCTIONS IMPORTANT STEPS KEY PINTS
- 1. Begin pre-startup check off
- 1. Completior cf list.
a prerequ-s te for COrtI '_1 t
ion of th -: 0. 1.
ao~
all items shoLd be rve'~
- 2. Pressurizer and RCS temp. &
- 2. Use readin2 sheet in crelcff press. readings will be taken list PSSO-36.
every 30 minutes from the time the pressurizer heaters are switched on until normal pressure of 2085 PSI is reached, unless TR-430, Fressurizer Temp.,
is in service
- 3. Reactor coolant system is filled,
- 3.
vented and solid, therefore:
- a. Provide monitoring to pre
- a. If the OMS is not operational vent overpressurizing assign a reactor operator to the R.C.S.
monitor the RCS pressure.
- b. Do not close MOV813 & 814, resi-
- b. To provide relief potri to dual heat removal inlets or RV206 and normal letdown LCV1112, CV202, 203 & 204 by PCV 1105.
normal letdown, except as required for RCS hydrostatic tests.
- 4.
Energize all pressurizer heaters
- 4. a. PC-430 J and associated con approximately one hour before trols should be on automatic.
starting reactor coolant pumps
- 1) R.V. 545 and 546
- 2) PC's 430 C & H
- b. Mark reactor plant group.
charts as per S-12-11
- 5. Start all reactor coolant pumps
- 5. Verify that reactor coolant in accordance with Operating system pressure is being main Instruction S-3-1.10 tamed at approx. 3 0 psi.
oRemove the residual heat removal system from service.
- a. Close HCV-602
- b. Stop the residual heat removal pumps
- c. Close MOV-833, and 834
- d. Adjust TCV-60b A & 601B set points to 115 0F.
SAN ONOFRE NUCLEAR GENERATING STATION OPERATING INSTRUCTION S-3-1.1 Revision 19
^.ut 17, 1978 IMFOPTANT ST Eps Y
- 7.
Open the 2" manual bypass valve
- 7. Valves ms: be e
e around the east RHR pump and verify an alternht ho ation the pumn manual suction and dis-path foll:na 1,
ant charce valves are open.
accident.
- 8. Sample and detennine reactor
- 8. Allow at TEest coolant systen boron and of reactc-Cool?
1+
oxygen zcor:entrations.
cuerat-
- Jue sample for Droorc
- 9.
Inject hydrazine as necessary
- 9. a. Recove -xc-d to lower oxygen concentration eralize-frc to <.1ppm.
before e
- dra-i ed.
- b. Place ed he U alizer ser c.2en scaven:'-.g is Co
- 10. Verify minimim flow is established in each pres surizer spray line (1/4 turn open on spray valve bypass valves).
- 11.
When pressurizer liquid
- 11. a. tllc.
iyste-vres~ure temperature reaches the to ir:-ease under t saturation temperature influence of t:e Dres for 350 psi (approximately surizer heaters.
4320), form the steam
- b.
Do not allow system bubb'e in accordance with
-press.re to exceed 0.1. S-3-1.11.
500 rsi uness sphere intec'ity is intaCt.
12, When the. steam bubble has been
- 12.
Do not aow syster pressure formed, disable the OMS by to excee-522 psi with the operating CS-3A and CS-6 OMS in tne enable position.
to the disable position.
- 13. When the reactor coolant
- 13.
Steam lea: upstream trap reaches 212-220*Fverify discharge shiould be routed the steam eads ari free to the blcwdown tank.
of water and theuN supply hose is disconnected.
- 14. Withdraw the first shutdown group of control rods to 320 steps.
- 15. Reduce boron concentration
- 14. a. bserve subcritical to the 4 shutdown value.
count rate.
See Operating Instruction
- b. Operate pressurizer S-3-2.5.
sprays to reduce Note:
See Precaution "N" presserizer and reactor this instruction, coolant boron concen tration differential as required.
SAN ONOFRE NUCLEAR GFNFRATIN STATION OPERATING INSTRUCTIOl S-3-1.1 Revision 19 - August 17, 1978 p
JMPORT ANT STEPS KEY i*5 Determine just critical rod position using Operating Instruction 5-3-1.3.
- 17.
Establish plant conditions
- 17.
Complete Peace e
required for critical Critical reactor operation.
PSSO-137.
l18.
As the reactor coolant temperature increases, maintain system pressure in accordance with the latest pressure temperature curve.
- 19.
At
- 1400 psi reactor coolant pressure, restore the safety injection line valve operating circuits to normal.
- 20.
Use the electric auxiliary feedwater pump as necessary to maintain steam generator water levelsat 50% as indicated by the narrow range recorders.
- 21.
Initiate warmup of secondary 21*Aflpen main steam lead 21 plant when reactor coolant block valve bypass valves.
temperature exceeds 400 *F.
B. Open hic-pressure extraction steam trap bypass valves and
- 22.
Start at least one condensate check al trap drains valved pump in accordance with to conaenser.
Operating2Instruction S-2-2.
- 23. Establish condenser vacuum as per Operating Instruc tion S-10-3.
- 24.
Stabilize reactor coolant system temperature at 5350 to 540 0F. and pressure at
.2085 psi.
0 0
SANONOFRE NUCLEAR GENERATING STATION OPERATING INSTRUCTION S-3-1.1 Revision 19 - Aujist 17, 1978 Pagc 7
- FAANT SIEPS,~KYPKT
- 25.
Conduct final survey of the
- 25.
Lock the cortainm'nt ;2Y?'c sphere prior to criticality.
following firnl survey.
Clear all cersonnel from the containment sphere and notify piant personnel that reactor startup has begun.
26 When reactor Pre-Critical
- 26.
If the critical rod has Check-Off List is complete, not been esta'lishe pull control rods to recent criti:wt\\ or criticality.
of precautica F ce l, tFe be guided by an inver rt rate plot p Operatrin 1 tructicn S-3-1.17.
- 27.
Establish - 0.5 dpm start up rate.
- 28.
Verify that high voltage supply to source channels is switched off when intermedi te channels reach 2 x 10-.
- 29.
If detectors in more
- 29.
Do'not readjust modified than one NIS power range channels Lrless 0 oower channels were replaced, reaings exceed 50 power.
reduce modified channel Readjust as necessary tut readings as appropriate to do rt re'uce rarlinos avoid actuation of the 10%
turbine permissive trip.
- 30.
Open main steam line 24" block valves.
- 31.
Start both feedwater pumps in accordance with Opera ting Instruction S-2-1.
32.. Verify stean dump on
- 32. PC-418 A set point at 900 psi.
pressure control to con cndenser and atmosphere.
33r Increase reactor power sufficiently to gain "-75%
opening on steam dump to condenser.
SAN ONOFRE NUCIE AR GENERATING STATION OPERATING INST JCTICi S--1.1 Revision 19-Auust 1/,
1973 Pa z IPORTANT STEPS K E P
- 34. Poll turbine in accordance
- 34.
Complete turbi:'r r
with Operating Instruction pre-star:
p L S-10-1.
- 35. Synchronize generator to 3
Load un': in system per Operating Instruc-with a tion S-6-13.
turbine S-9-2.
- 36.
increase generator lbad to 25
- 36.
Y"4e.
Place main feedwater verif),,:. loc2i1r that contrtl valves in service.
regulatc-rbin s arre e
r ic the verify,y oilis
,ta MOV's wen opr:ing urtl it is verifie: the nin re; icting valves a-e holding.
- 37.
Return oscillograph initiation
- 37.
Generator under ar: o..
.,tage switches to normal.
switches #4 & 9.
- 38. Transfer 4KV auxiliary power system.
4KV.bus 1A to Transformer A, 4KV bus 18 to Transformer B, 4KV buses IC and 2C remain on Transformer C.
Refer to Operating Instruc tion S-6-5.
- 39. Increase load on unit in
- 39.
Isotopic analysis for iodine shal accordance with Operating-be made between 2 and 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> Instruction S-9-2, Turbine following a thermal power change Reheater Operatinq anT' of >15%%ithin a one hor period.
Station Order S-0-107, Minimum Load and Pickup A v a ilab-ity.
- 40. Switch Steam dump to auto at 15% load.
SAN ONOFRE NUCLEAR GENERATINl STATION OPERATING INSTRUCTION S-3-1.1 Revision 19
- August 17, I;S8 I! f'OTANT STEPS KEY N TS
- 41.
If detectors in more than one. NIS noier range channels were replaced, perform a thermal calibration and adjust all channels as required prior to switch ing NtS made cf operation switch to mid.
- 42. Switch NIS rode of operation
- 42.
Sct o e:.:we r:c switch to Mid.
80' F.P.
- 43.
At 20" load slowly reduce stean lenerator levels to the 30. automatic set point and place feedwater and reactor controls on auto.
- 44. Start heater drain pumps per Operatinq Instruction S-2-3.
45.. Place reheater steam dump
- 45.
See Ope-atinq nscr..r system in service.
S-9-2 Thrbine Reheat Operation.
VI.
FINAL CONDITIONS A. The turbine-cenerator is on the line at approximately 20' load V ir all systems. normal for operation and all controls on automatic.
J.M. Curran
- Indicates revision Plant Manager JER/yc
FREC0~,VlAENDED STR P I it-Ttt6 TIMES FOR VAROUS NTLUIN
%fwo IN F ASE j
0LOAD0030 uNTALjTU~N NowU S 8A B R M T L TE P(E.F 1
j
SAN. ONOFRE NUCLLAR G;EN ING SIAT10U UP LKIik i AsIo
-l.
Revision 6 - December 1, 1977 FEEDWATER CONTROL MODE TRANSFER AND OPERATIONS I.
OBJECTIVE This instruction d,?scribes the tr~frand m3nuall cperat'.ccn c't7 feedwater controls during unit startup. shutdown and' power o per e "J:
II.
CONDITIONS A.
Feedwater operation during unit startup.
L B. Feedwater operation during unit shutdown.
C. Transfer of feedwater controls during power operaticr.
III. PRECAUTIONS A. Care must be exercised to perform feedwater control transfers ir.
a "bumpless" manner to avoid large swings in feedwater flor, B. Large, rapid increase in feedwater flow will result in a po.itivc reactivity insertion.
C. During startup, the main feedwater regulators should be che kod for proper operation prior to opening the feedwater M.O.V.
D The feedwater controls should be transferred to manual following a unit trip and prior to removing the unit from service during a planned shutdown. Level should be controlled at 50% as indicate on the narrow range recorders. This will prevent possible swings in feedwater flow from uncovering the feedring.
E. While at low loads or off line on manual feedwater control, be particularly alert to changes in steam generator level caused by adjustments to blowdown or other perturbations which might cause the feedring to be uncovered.
F. The feedwater controller shall be placed in manual when work is to be performed on steam flow, feedwater flow, and/or steam generator level transmitters and associated circuits..
G. When work Is to be performed on the pressure transmitter used for compensation or its associated circuits, all three feedwater controls shall be placed in manual control.
H. The steam generator feedring becomes uncovered if level is allowed to decrease below 26% as indicated on the narrow range level instrumentation.
If feedwater flow to a steam generator is interrupted or the feedring be comes uncovere f dw o
eir flow should be re-established slowly to avoid water hor
.W C P...
- a.
If water h m e U E[ s e an immediate visual inspection should be~cEr 6MV- -pjp;hanger and supports on the system outside the containment~~~
or evidence of line movement shall be reported to the Watch Engineer who will determine the course of action.
SAN ONOFRE NUCLEAR GENERATING STATION OPERATING INSTRUCTION S-3-2.27 Revision 8 -
Decelber 13;*1977 IV. CHECK OFF LIST (Not Applicable)
V. INSTRUCTIONS A. Unit startup.
Im'ortant Steps Key Points
- 1. Maintain steam generator water level
- 1. Main feedwat c e
at 50' narrow range indication using ar-
.'S ?e.a the auxiliary feedwater regulators.
closed. The co c
are in ranua l.
- 2. At 10% of full load jog open the
should be cyc e pwic l
to opennrK.,
thec This. will assure that the rerulators are straking procerly.
- 3. Transfer steam generator level con-
- 3. a. SI:,;y 0p e
r.ei trol to the main feedwater regula-re: ator
- c. c s ng tors.
the auxiliary t. maintain co-stant water levl.
- b. The auxiliary regulators can maintain steam qn erator water level up to "-20% of full load.
- 4. At 20% of full load slowly reduce steam 4. See part C of this instruc generator levels to the 30% automatic tion.
set point and.transfer feedwater controls to automatic.
B. Unit Shutdown Important Steps Key Points
- 1. At 20% of full load transfer the feed-1. See part C of this instructic water controls to manual. Slowly raise
- a. Alert switch to manual ale the steam generator levels to 50% as is set at 15% load.
indicated by the narrow range recorders.
- 2. At about 15% of full load transfer the 2. Slowly open the auxiliary steam generator level control to the feedwiater regulators while auxiliary feedwater regulators.
closing the main to maintain constant water level.
- 3. Monitor the steam generator and 22.
levels for changes during th operation.
C. Transfer of feedwater controls during power operation.
Transfer from automatic to manual
.SOPE )TING INSTRUCTION S-3-2.27 SAN ONOFRE NUCLEAR GENEP.ATIG STATIN Ea 3
Revision 6 -December 13.17 Lrol~cnt~
1-C oBD
- 1. Adjust razual control knob to ctO" l.
to ea r
nullmeter indication on RM0.
output.
1 2. Observe fed osteam
- 2.
Transfer the controller to manual generator 'e'.1 Ct ar
-e by operati tng t oe Ranual" position.
recorder a.
on bges.
0eserve rontroller outout meter to assure r m during and after transfer.tohl 3.Awy
- 3.
Adjust manual control knob to hold
- 3. Alhaychonse c desired level.
when chan%
t tz Transer fom Manual to Automatic Imortn Steps
-Ke
- 1. Adjust manual control knob to balance steam-feedwater flow pens as close together as practical.
- 2. Adjust set point control knob to
- 2. This oper20 an u
"0" nullmeter indication on RMC.
control sro;nawi Wan t
3.Transfer the controller to auto-
- 3. Observe f:-e~water flow anzi steam Transfer the "Manual -
generator level on assoc'ated Aati mb copeeating n
"Auto-recasdereaftemathiss t onnges.io Automatic' selector switch to At-rcdeatrthsocain matic" position. Observe controller to assure no mnajor sv ings/ changes.
output meter during and after transfer.
- 4.
Adjust set point control knob to hold desired level.
VI.
FINAL CONDITION The feedwater controllers are in automatic and controlling the steam generator water levels.
B. The steam generator water levels are being remote manually controlled by. the auxiliary feedwater regulator$4 C. After completion of the first part of this section, the feedwater regulators are under control of the manual knob on the associated R.M.C.
After completion of the second part of this section the feedwater regu lators are controlled automatically. Level set -,int adjustm~ent is possible by operation of the set point control ptodob on the associated RML J. M. CURRAN PLANT MANAGER 4
IPHP:sel
- Indicates revision