ML20204J313
| ML20204J313 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 07/18/1986 |
| From: | Devincentis J PUBLIC SERVICE CO. OF NEW HAMPSHIRE |
| To: | Starostecki R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| (CDR-86--7), (CDR-86-00-07), SBN-1162, NUDOCS 8608110056 | |
| Download: ML20204J313 (19) | |
Text
'
" ~ l
- 5) SEABROOK STATION l
. . Enginssring Offica '
. u July 18, 1986 Put2c Service of New HampeNro SBN- 1162 T.F. Q2.2.2 NEW UAMPSHIRE YANKEE DIVISION United States Nuclear Regulatory Commission Region I 631 Park Avenue King of Prusola, PA 19406 Attention: Mr. Richard W. Starostecki, Director Division of Project and Resident Programs
References:
(a) Construction Permits CPPR-135 and CPPR-136, Docket Nos. 50-443 and 50-444 (b) Telecon of June 6,1986, W. J. Daley (YAEC), M. A.
Chiasson (NHY), R. W. Gregory (YAEC) to Rick Urban (NRC - Region I)
Subject:
Final 10CFR50.55(e) Report: Emergency Core Cooling System Design Deficiency (CDR-86-00-07)
Dear Sir:
In Reference (b), we reported a 10CFR50.55(e) deficiency regarding the valve alignment of the Emergency Core Cooling System (ECCS) at Seabrook Station during the cold leg recirculation phase of post-LOCA ECCS operation.
Description of Deficiency During the cold leg recirculation phase of post-LOCA ECCS operation, each Low Head Safety Injection (RHR) pump takes suction from the containment sump and discharges directly to two Reactor Coolant System (RCS) cold legs and to a suction header common to both High Head Safety Injection (SI) pumps and both High Head Centrifugal Charging (CS) pumps. In the event that one of the fully redundant RHR pumps failed, the remaining active RHR pump would discharge directly to two RCS cold legs, to the common suction header, and to the alternate two RCS cold legs via the discharge line of the failed pump. The availability of the latter flowpath, which was previously unaccounted for in system design analyses or testing, would reduce the NPSH provided to the CS pumps below the required NPSH.
I 8608110056 860718 PDR ADOCK 05000443 S PDR I
I \
5 Seabrook Station Construction Field Office . P.O. Box 700
- Seabrook, NH O3874
United States Nuclear Regulatory Commission SBN-ll62 Attention: Mr. Richard W. Starostecki Page 2 Safety Implications Failure of an RHR pump during the cold leg recirculation phase of Post-LOCA ECCS operation could result in damage to both high head CS pumps.
This in turn would reduce the long term core cooling capabilities of the ECCS.
Corrective Action A low head safety injection system valve alignment will be used which is different than that provided in the FSAR for the cold leg recircu-lation mode. This alignment will provide acceptable system hydraulic characteristics and still meet core cooling requirements. The FSAR changes reflecting the new alignment are provided herewith in Attachment
- 1. In addition the new alignment has already been incorporated in Seabrook Station's emergency operating procedures.
The above referenced FSAR change will be incorporated into the FSAR by a future amendment. In this regard it should be noted that we are also sending a copy of this letter to NRR to apprise them of these FS AR changes.
This letter is being filed as a final 10CFR50.55(e) report.
Very truly y urs, 1$
John DeVincentis Director of Engineering Attachment ec: Atomic Safety and Licensing Board Service List Director, Office of Inspection and Enforcement United States Nuclear Regulatory Commission Washington, DC 20555 Mr. Vincent S. Noonan, Project Director PWR Project Directorate No. 5 United States Nuclear Regulatory Commission Washington, DC 20555 4
- - - - - - - , - . . , , ,, ------,---...--.y , - , - ,-
,' ',"hicn2Curr:n,E:quiro Patsr J. Mathtwa, Mayor City H 11
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, H;rmon & Welco 2001 S. Street, N.W. Newburyport, MA 01950 Suite 430 Washington, D.C. 20009 Judith H. Mizner Silvergate, Gertner, Baker, Sherwin E. Turk, Esq. Fine, Good & Mizner Office of the Executive Legal Director 88 Broad Street U.S. Nuclear Regulatory Commission Boston, MA 02110 Tenth Floor Washington, DC 20555 Calvin A. Canney City Manager Robert A. Backus, Esquire City Hall 116 Lowell Street 126 Daniel Street P.O. Box 516 Portsmouth, NH 03801 Manchester, NH 03105 Stephen E. Merrill, Esquire Philip Ahrens, Esquire Attorney General Assistant Attorney General George Dana Bisbee, Esquire Department of The Attorney General '
Assistant Attorney General Statehouse Station #6 Office of the Attorney General Augusta, ME 04333 25 Capitol Street Concord, NH 03301-6397 Mrs. Sandra Gavutis Chairman, Board of Selectmen Mr. J. P. Nadeau RFD 1 - Box 1154 Selectmen's Office Kennsington,. NH 038*7 10 Central Road Rye, NH 03870 Carol S. Sneider, Esquire Assistant Attorney General Mr. Angie Machiros Department of the Attorney General Chairman of the Board of Selectmen One Ashburton Place, 19th Floor Town of Newbury Boston, MA 02108 Newbury, MA 01950 Senator Gordon J. Humphrey Mr. William S. Lord U.S. Senate Board of Selectmen Washington, DC 20510 Town Hall - Friend Street (ATTN: Tom Burack) Amesbury, MA 01913 Richart A. Hampe, Esq. Senator Gordon J. Humphrey Hampe and McNicholas 1 Pillsbury Street l 35 Pleasant Street Concord, NH 03301 l Concord, NH 03301 (ATTN Herb Boynton) i Thomas F. Powers. III H. Joseph Flynn, Esquire l Town Manager Office of General Counsel Town of Exeter Federal Emergency Management Agency l
10 Front Street 500 C Street, SW Exeter, NH 03833 Washington, DC 20472 Brentwood Board of Selectmen Paul McEachern, Esquire l RFD Dalton Road Matthew T. Brock, Esquire Brentwood, NH 03833 Shaines & McEachern
! 25 Maplewood Avenue l Gary W. Holmes, Esq. P.O. Box 360 Holmes & Ells Portsmouth, NH 03801 47 Winnacunnet Road j Hampton, NH 03842 Robert Carrigg l
Town Office
- Mr. Ed Thomas Atlantic Avenue FEMA Region I North Hampton, NH 03862 442 John W. McCormack PO & Courthouse Boston, MA 02109
- . SBN-1162 SB'l & 2 Amendment 56 FSAR November 1985 TOJCh the automatic and manual switchover sequence, the two residual heat removal pumps would take suction from the containment sump and deliver borated water directly to 7 RCS cold legs. A portion of the Number 1 residual heat remova pump discharge flow would be used to provide suction to the two charging pumps which would also deliver directly to the RCS cold legs. A portion of the discharge flow from the Number 2 residual heat removal pump would be used to provide suction to the two safety injection pumps which would also deliver directly to the RCS cold legs. As part of the manual switchover procedure (see Table 6.3-7, Step 4), the suctions of the safety injection and charging pumps are cross connected so that one residual heat removal pump can deliver flow to the RCS and both safety injection and charging pumps, in the event of the failure of the second residual heat removal pump.
After approximately 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br />, cold leg recirculation is terminated and hot leg recirculation is initiated. This is done to terminate any boiling in the core should the break be in one of the RCS cold legs. During this phase of recirculation, the SIP's discharge is aligned to supply water to all four RCS hot legs and the RHRP's discharge is aligned to supply water to RCS hot legs 1 and 4. The CCP's do not have the capability to feed the hot legs and continue to supply the cold legs.
6.3.2.2 Equipment and Copponent Descriptions The component design and operating conditions listed in Table 6.3-1 are l 56 specified as the most severe conditions to which each respective component is exposed during either normal plant operation, or during operation of j the ECCS. For each component, these conditions are considered in relation to the code to which it is designed. By designing the components in accordance with applicable codes, and with due consideration for the design and operating conditions, the fundamental assurance of structural integrity of the ECCS component s is maintained. Components of the ECCS are designed to withstand the appropriate seismic loadings in accordance with their safety class as given in Table 3.2-2.
Descriptions of the major mechanical components of the ECCS follow:
- a. Accumulators The accumulacors are pressure vessels partially filled with borated l
water and pressurized with nitrogen gas. During normal operation, l each accumulator is isolated from the RCS by two check valves in
! series. Should the RCS pressure fall below the accumulator pressure, the check valves open and borated water is forced into the RCS. One accumulator is attached to each of the cold legs of the RCS.
Mechanical operation of the swing disc check valves is the only action required to open the injection path from the accumlators to the core via the cold leg.
l 6.3-5 .
L
o ..'
- b. Passive Failure Criteria The following design philosophy assures the necessary redundancy in component and system arrangement in order to meet the intent of the General Design Criteria on single failure as it specifically applies to failure of passive components in the ECCS. Thus, for the long term, the system design is based on accepting either a passive or an active failure.
- 1. Redundancy of Flow Paths and Components for Long Term Emergency
- Core Cooling In design of the ECCS, Westinghouse utilizes the following criteria:
(a) During the long term cooling period following a loss of coolant, the emergency core cooling flow paths shall be separable into two subsystems , either of which can provide minimum core cooling functions and return spilled water from .the floor of the containment back to the RCS.
(b) Either of the two subsystems can be isolated and removed from service in the event of a leak outside the
. containment. Rh-f mde opM A. AlJe s ange2- .*%
saric.s ara.- proJ.*.kl. Ac %:- helo~ tion W u b ,
(c) Adequate redundancy of check valves is provided to tolerate failure of a check valve during the long term as a passive component.
(d) , Should one of these two subsystems be isolated in this long term period, the other subsystem remains operable.
(e) Provisions are also made in the design to detect leakage from components outside the containment, to collect this leakage, and to provide for maintenance of the af fected equipment.
A single passive failure analysis is presented in Tgble 6.3-6.
It demonstrates that the ECCS can sustain a single passive failure during the long term phase and still retain an intact flow path to the core to supply sufficient flow to maintain the core covered and af fect the removal of decay heat. The procedure followed to establish the alternate flow path also isolates the component which failed.
Th u s , for the long term emergency core cooling function, adequate core cooling capacity exists with one flow path removed from service.
6.3-15
- l
. i S3152 Amendment 53 FSAR April ' 95o to actuate the spray, but not high enough to seat the check valves referenced above. This would result in a continued high flow rate from the tank until the RWST isolation valves (CBS-V2, VS) are closed (approximately 75 seconds after "lo-lo-1" signal by Table 6.3-10. From this point there is at least 5.1 minutes of operation at 1,800 gpm, for a total of 6.4 minutes before the "ampty" alarm sounds. There is at least 31.0 minutes of operation atween the "lo-lo-1" and possible vortexing in this case. gg 51 The limiting single failure for the design is-the failure of one of the RWST isolation valves (CBS-V2, -VS) to close. If one of these valves does not close, the flow race drops from 16,400 to 9,100 gpm (not 1,800). At this high flow race, the " empty" alarm will sound, alerting the operator to immediately shut off any pumps still taking suction from the tank. There is sdfficient volume between the " empty" alarm and the calculated vortexing level for at least 1.9 minutes of operation for shutting off the pumps. l
/b.Y> 45 53 Following the automatic and manu switchover sequence, the two residual 53 heat removal pumps would take uction from the containment sump and deliver borated water directly to RCS cold legs. A portion of the Number 1 residual heat removal pump discharge flow would be used to provide suction to the two charging pumps which would also deliver directly to the RCS cold legs. A portion of the discharge flow from the Number 2 residual heat re-moval pump would be used to provide suction to the'two safety injection pumps .
which would also deliver directly to the RCS cold legs. As part of the manual switchover procedure (see Table 6.3-7, Step 4), the suctions of the safety injection and charging pumps are cross-connected so that one residual heat removal pump can deliver flow.to the RCS and both safety injection and charging pumps, in the event of the failure of the second residual heat removal pump.
See Section 7.5 for process information available to the operator in the control room following an accident.
45 9
6.3-18b
SB 1 & 2 Amendment 56 FSAR November.1985 1
]
6.3.3 Performance Evaluation Chapter 15 accidents that result in ECCS operation are as follows:
- a. Inadvertent opening of a steam generator relief or safety valve (see Sec tion 15.1.4) .
- b. Small break. LOCA. (see Se.ctio.n 15.6.5).
- c. Large bYeak LOCA (see Section 15.6.5) .
- d. Majo'r secondary system pipe failure (see Section 15.1.5) .
- e. Steam generator tube failure (see Section 15.6.3) .
Safety injection is actuated from any of the following:
- a. Low pressurizer pressure.
- b. Low steamline pressure.
- c. High containment pressure.
- d. Manual initiation.
A safety injection signal will rapidly trip the main turbine, close all feedwater control valves, trip the main feedwater pumps, and close the feed-water isolation valves.
Following the actuation signal, the suction of the centrifugal charging pumps is diverted from the volume control tank to the refueling water storage tank.
Simultaneously, the valves isolating the charging pumps from the injection header automatically open. The safety injection pumps also start automatically but operate at shut off head when the RCS is at normal pressure. The passive 5' injection system (a'ecumulators) and the low head system (residual heat removal pumps) also provide no flow at normal RCS pressure.
Figure 6.3-2 is a simplified illustration of the ECCS. The notes provided with Figure 6.3-2 centain information relative to the operation of the ECCS in its various modes. The modes of operation illustrated are full operation of all ECCS components. cold leg recirculation with residual heat removal pump Number 2 operating, and hot leg recirculation with residual heat removal pump Number 1 operating.1 e ar gp(gytyfo it ona rep /epnta/ivfoI[e/opfaf'on[52hfEKS dfri[>
Lag times for initiation and operation of the ECCS are limited by pump startup time and consequential loading sequence of these motors onto the safeguard 6.3-19
. ." 1 I
1 in 1 5 .
ESAR NOTES TO FIGl'RE 6.1-2 (Sheet 1 of 19)
MODES OF OPERATION MODE A - INJECTION -
This mode presents the process conditions' for the case' of maximum safeguards ,
i.e., all pumps operating, following accumulator delivery. Two residual heat removal (RHR) pumps, two safety injection (SI) pumps, and two centrifugal charging (CC) pumps operate, taking suction from the refueling water storage tank and delivering to the reactor through the cold leg connections. Note that the flow from each pump is less than its maximum runout since the pump discharge piping is shared by the two pumps of each subsystem. Note also that the SI pump branch connections to the residual lines are close to their discharge into the accumulator lines. thereby minimizing any increase in the RHR branch line head loss due to the combined flows of the RHR and SI pumps.
MODE B - COLD-LEG RECIRCULATION This mode presents the process conditions for the case of cold-leg recirculation assuming residual heat removal (RHR) pump No. 2 operating, safety injection pumps 1 and 2 operating, and centrifugal charging (CC) pumps 1 and 2 operating.
It is assumed that the spray pumps have emptied the RWST at this time.
In this mode the safeguards pumps operate in series, with only the RHR pump capsble of taking suction from the containment sump. The recirculated coolant is then delivered by the RHR pump to both of the SI pumps which deliver to the reactor through their cold-leg connections and to both of the CC pumps which deliver to the reactor through their cold-leg connections.
The RHR pum also elivers lees tit R is g flowdirect1,y_{tothereactorthroughtwoco tot , onnef v ~1v ~ ar (ffe/_n _
a s er rm nj c o to ecrcupttyk _ , _ _
MODE C - HOT-LEG, RECIRCULATION This mode presents the process conditions for the case of hot-leg recirculation, assuming residual heat removal (RHR) pump No. 1 operating, centrifugal charging (CC) pumps 1 and 2 operating, and safety injection (SI) pumps 1 and 2 operating.
In this mode, the safeguards pumps again operate in series with only the RHR pump taking suction from the containment sump. The recirculated coolant is then delivered by the RHR pump to both of the CC pumps which continue to deliver to the reactor through their cold-leg connections and to both of the SI pumps which deliver to the reactor through their hot-leg connections.
The RHR pump also delivers directly to the reactor through two hot-leg connections.
l I
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- . , . _ , _ _ - - _ . _ . - ~ , - , - - - - - - - - - - - , - -
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33 1 ,2 A=endmen: I; 73A3 May '.136 NOTES TO FIGURE 6.3-2 (Sheet 3 of 19) .
VALVE ALIGNMENT CHART (Cont'd)
OPERATIONAL MODES VALVE NUMBER >
A -
B_ C 21 C 0 0 22 0 @C 0
$6 23 0 h-0 0 24 0 0 C 25 C C 0 26 0 % -C, C 27 C C C 28 0 C C 29 C 0 0 30 C C C 31 C C C I
35 0 0 0 5 i
e e
0 = OPEN C = CLOSED e
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TABLE 6.3-5 -
(Sheet 5 of 10) . ,^
Component Failure Mode ECCS Operation Phase *Effect on System Operation ** Failure Detection Method ) Remarks
- 11. Motor Fails to close Recirculation - cold Failure reduces redundancy Same method of detection Valve is electrically l operated on demand. legs of RC loops, of providing flow isolation as that stated for item #4. interlocked with iso- 3e gate valve of Containment Sump from lation valve CBS-V8 CBS-v2 RWST. No etfact on safety and RH-V35 and may not (CBS-v5 for system operation. be opened unless these analogous) Alternate check isolation ,
valves are closed, for valve CBS-V55 provides manual operation from backup isolation. _ main control board.
- -. Valve opens automati-
. cally on "S" signal.
r
- 12. , Mo t - Fai s oy6 Re ref at p - Fall er uc a re da y Sa me ofJetef'tpn ' l op rat d ga o de n ,f gsjefRyloop/[oif
- s. of ovi n LHSI as a teffoyrinfe fu v i RH-V . tr as er tion for -
RH 21 r irc a on o flu d to an ogou Id es of S. ,*
m effe e saf ty f r sy t W o at n. Its te so @,
1 to val RH 21 p ov des >
c p is att for I/ ,
A pump rai sepa at on. _
N
~
- r j 13. Motor operated Fails to clos. Rectreulation - cold Fatture reduces redundancy Same method of detection valve is electrically l globe valve on demand. legs of RC loops. of providing isolation of' as that stated for item #4. interlocked with 1so- %
4 SI-V9 3 HHSI/SI pump's miniflow lation valves RH-V35 line isolation from RWST. and RH-V36 and may No effect on safety for not be opened unless system operation. Alter- - these valves are nate isolation valves SI-V89 closed, and SI-v90 in each pump's 3 miniflow line provide back- r
~
up isolation. -
- 14. Motor operated Fails to close Recirculation - cold Failure reduces redundancy Same method of detection Same remark as that l globe valve on demand. legs of RC loops. of providing isolation of as that stated for ites f4. stated for item #16, % .a -
SI-V90 HHSI/SI pump SI-P-6A mini- G g
(SI-V89 flow isolation from RWST. a -
analogous) No ef fect on safety for system operation. Alter-
[{3 nate isolation valve $
SI-V93 in main miniflow -n line provides backup jm i
isolation. w= a i
. , y*
TABLE 6.3-5 (Sheet to of 10) .
Failure Mode ECCS Operation Phase *Effect on System Operation ** Failure Detection Method Remarks Component Same method of detection Valve is electrically {
- 15. Motor operated Fails to open Recirculation - cold Failure reduces redundancy
- on demand. legs of RC loops, of providing NPSH to suc- as that stated for itea Q ; interlocked with iso- %
aste valve tion of HHSI/CH pumps from slation valves SI-V90, RM-V35
- j Y ISI-V89 SI-V93, RC-V23, LHSI/RNR pumps. No safety effect on system operation. JRC-V22 and CBS-V8.
i . Valve can not be opened Minimum HPSR to HHSI/CH pump suction will be met by -
iunless valve SI-V93 or l
- flow f rom IJISI/RHR pimp {SI-V90andSI-V89 tvalves are closed; RH-P-8B via cross-tie line f and opening of isolation - valve RCS-V23 or j T RCS-V22 is closed, valve CS-V460 or CS-V461 and teolation valve RM-V36. [and CBS-V8 is open.
]
Recirculation - cold Failure reduces redundancy Same method of detection ! Valve is electrically l
]6, Motor operated Fails to open interlocked with iso- %
gate valve on demand. legs of RC loops. of providing NPSH to suc- as that stated for item h lation valves, SI-V90, ;.r.
l RH-V36 tion of HHSI/SI pumps from jY- W LHSI/RHR pumps. No effect SI-V89, SI-V93, CBS-Vl4, on safety for system opera- RC-V88 and RC-V87. $-
tion. Minimum NPSH to HMSI/ Valve cannot be opened y, SI pump suction will be met unless valve SI-V93 N by flow from IJtSI/RHR pump or SI-V90 and SI-V89 valves are closed; I RH-P-8A via cross-tie line and opening of isolation valve RC-V88 or valve CS-V460 or CS-V461 RC-V87 is closed and and isolation valve RX-V35. valve CBS-V14 is open.
- 17. Motor operated Fails to open Recirculation - cola Failure reduces redundancy Same method of detection l g.
gate valve on demand. legs of RC loops. of providing fluid flow as stated for itc h CS-V460 through cross-tie between *
(CS-V461 suction of HHSI/CH pumps analogous) and HHSI/SI pumps. No effect on safety of system operation. Alter- ,
nate isolation valve (CS-V461 opens to provide z
. backup flou path through $g cross-tie line.
oa a3 cr 1 Failure reduces redundancy Same method of detection n3
- 18. Motor operated Fails to close Recirculation - cold " j gate valve on demand. legs of RC loops. of providing flow isolation as that stated for item f4. b'" a CBS-V47 of HHSI/SI pump suction *
, (CBS-V51 from RWST. No effect on u+
analogous) safety for system operation.
Alternate check isolation valve (CBS-V48) provides backup isolation.
4
.s
- r.*
TABl.E 6. 3-5 (Sheet 7 of 10) .
Component railure Mode ECCS Operation Phase *Effect on System Operation **railure Detection Method Remarks
.c
- 19. Motor operated rails to clos. Recirculation - cold railure reduces redundancy Same method of detection l gate valve on demand. legs of RC loops. of providing flow isolation as that stated previously c,g LCV-112D of suction of HHSI/CH pumps for failure of iten during (LCV-112E from RWST. No effect on injection phase of ECCS analogous) - safety for system operation. operation.
Alternate check isolation valve (CES-V58) provides backup isolation.
- 20. Residual rails to Recirculation - cold ratlure reduces redundancy Same method of detection l heat deliver work- legs of RC loops, of providing recirculation as that stated previously g pump RM-P-8A ing fluid. of coolant to the RCS from for failure of item during (pump RN-P-85 the Containment Sump. injection phase of ECCS analogous) Fluid flow from 1.HSI/RHR ' operation.
pump RH-P-8A will be lost.
Minimum recirculation flow requirements for 1.HSI flow will be met by 1.HSIf en RRR pump RH-P-88 deliver-ing fluid. y"
) so e
- 21. Safety rails to Recirculation - cold railure reduces redundancy Same method of detection I injection deliver work- or hot legs of RC of providing recirculation as that stated previously $4.
pump SI-P-6A ing fluid. loops. of coolant to the RCS from for failure of item during (Pump SI-P-68 the Containment Sump to injection phase to ECCS analogous) cold legs of RC loops yta operation.
RHR and SI pumps. Fluid flow from HHSI/SI pump SI-P-6A will be lost.
Minizia recirculation flow -
requirements for HHSI flow will be met by HHSI/SI pump SI-P-6B delivering working fluid.
- 22. Motor operated rails to close Recirculation - hot railure reduces redundancy Same method of detection l gate valve on demand. legs of RC loops, of providing recirculation as that stated for item #4. c, =
Od RH-V14 of coolant to the RCS from the Containment Sump to hot -
yj legs of RC loops. Fluid cr o.
flow f rom IJISI/RHR pump @@3 RH-P-8A will continue to re f ow to cold legs of RC j g g. g M' F " $$
4'ICW %W ' '% I IO belf f ow re ut e t .
5 e o 1 p t y /R of SC $ oops h bA ommc1 hy U6I /MI' P"*P p H - rc cu t n I88 9-Ed rede& A -laie [h#-MA. C' MC hot /Ep la d a t eg te t kdh Qm g gM
u l TABl.E 6. F5 (Sheet 8 of 10)
Component Failure Mode ECCS Operation Phase *Effect on System Operation ** Failure Detection Method Remarks t'
1
< (2 . No r ted Fa at n Re ulat on Tail e re es d acy Valv pos ton ndi att n k .
te a o n of p of ovid re ircu tion (el ed o p it n 1 %
g 22 of ool t to R fr c nge) at . al J ! t at tS to ose osi on ni or na ogous) leg of P loo . lig and la a MC .
l Flu flow rom I/ In ddi on, HR
! p RH-P w I be ost d chayge p ess re PI- 4)
M inum cir lat a f1 a MCT.
quir nts o le or RC oops ill b LHSI HP p P-8
. ree cul ing luid o ho leg dir tly la H I/SI pump .
. Motor operated Tails to open Recirculation - hot Failure reduces redundancy Same method of detection as $
gate valve on demand, legs of RC loops. of providing recirculation that stated for item M % ]"
M RB-V32 of coolant to the RCS from a
We (RH-V70 the containment sump to the hot legs of RC loops. No y~
analogous) effect on safety for syst a operation. Alternate isola-
! tion valve (RM-V70) opens to provide flow path to RCS l
hot legs via IJESI/RMR pumps.
I
. Motor operated Fails to close Recirculation - hot Failure reduces redundancy Same method of detection
, gate valve on demand. legs of RC loops. of providing recirculation as that stated for item #4. $*
j RH-V26 of coolant to the RCS from the Containment Sump to hot 1ess of RC loops. Fluid J flow from LH5I/RHR pump I RH-P-8B will continue to .
i flow to cold less of RC Z c a on l .
/f loops.
r q ir
~1 e s o t - (ksacg h 3-4 UMIC+" *g kk
{ea f C1 e il b ggy g,3 3 3 m' h aJ.ts Nc!rc A -@ $
e ir ul t f ut d e 1 " %
t as a by I h5cd f.f Jcc.pf, b bb M by :s la i p F R ec r -
f id a he t t J5the P A& M -P-WA rec $fW\5 "
T 5 dWgh *D *u C
gs v1 HHS / p . j gA oul. 4o. ##.51 -51 pwrnos-
1 TAst.E 6.3-5 (Sheet 9 of 10)
Component Failure Mode ECCS Operation Phase *Effect on System Operation ** Failure Detection Method Remarks
. Motor operated Fails to close Recirculation - hot Failure reduces redundancy Same method of detection l gate valve on demand. legs of RC loops. of providtag flow isolation as that stated for item f4. g
.25 SI-vitz of uuSI/SI pump flow to cold (SI-Vill lege of RC loops. No effect analogous) on safety for system opera-
. tion valve SI-V114 provides backup isolation against flow to cold legs of RC loops.
. Motor operated Fails to open Recirculation - hot Failure reduces redundancy Same method of detection as gate valve on demand. legs of RC loops, of providing recirculation that stated for item #6. g M SI-V102 of coolant to the hot lege In addition. SI pus'y dis-charge pressure (FI-919)
(SI-V77 of RCS from the Conta1 ament analogous) Sump via intSI/SI pumps. and flow (FI-918) at MCB. cn Minimum recirculatico flow tp requirements to hot less 2 of RC loops will be met by IJtSI/RMR pump RN-F-8A and EM-F-85 recirculating fluid N i
from Containeset Sump to hot less of RC loops and IDISI/SI .
pump SI-F-68 recirculating fluid to hot less 2 and 3',of RC loops through the open-ing of isolation valve -
SI-V77. -
. Motor operated Fails to close Recirculation - hot Failure reduces redundancy Same method of detection gate valve on demand. legs of RC loops. of providing flow isolation as that stated for item f4. g JJ SI-Vil4 of IntSI/SI pump flow to cold legs of RC loops. IIo effect
! on safety for system opera-tion. Alternate isolation =
valves SI-V112 and SI-Vill o>
in cross-tie line between $5 IIIISI/S1 pumps provides back- g{
up isolation against flow 1 a" to cold lege of RC loops. "
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TABLE 6.3-7 (Sheet 1 of 3)
SEQUENCE OF SWITCHOVER OPERATIONS
. (BASED ON NO SINGLE FAILURES)
The following manual operator actions are required to complete the switchover from the injection mode to the recirculation mode. During the injection mode, the operator verifies that all ECCS pumps are operating and monitors the RWST and reactor building recirculation sump levels in anticipation of switchover.
Component cooling water flow to the residual heat removal heat exchangers is automatically initiated on a 'T' signal. The operator ve,rifies that the component cooling water inlet isolation valves to the residual heat removal heat exchangers are open prior to switchover initiation. Motor control centers E522 and E622 are energized and the engineered saieguards signal is reset prior to switchover.
The following manual actions must be completed in a timely manner following switchover initiation to align the charging pumps and safety injection pumps suction to the residual heat removal pumps discharge.
SWITCHOVER STEPS The RWST " low-low" level signal in conjunction with an 'S' signal automatically initiates the opening of the containment sump isolation valves (CBS-V8/V14). '
STEP 1 When each sump isolation valve (CBS-V8/V14) has reached the full open position, take insnediate action to close the corresponding RWST/RHR pump suction isolation valve (CBS-V2/VS).
STEP 2 Close the three safety injection pump miniflow isolation valves (SI-V89/V90/V93).
STEP 3 "C o v R /rgdsp'o)/ey' %r)4 46wdsgreyfn of tWe J01 STEP 4 Open the two parh11e1 valves in the consnon suction line between the charging pump suction and the safety injection pump suction (CS-V460/V461).
STEP 5 Open each valve from each RHR pump discharge line to the charging pump suction and to the safety injection pump suction (RH-V35/V36).
STEP 6 All ECCS pumps are now aligned with suction flow from the containment sump. Verify proper operation and alignment of all ECCS components and proceed to complete the following manual actions to provide redundant isolation of the RWST from the recirculation fluid.
Clasa ana. usl,k. ta.3 .af u:t,'an pah isalato'an v.d ve ds+ s4 rw c4pe wica.e % cs (w-Vm ar- An-V.%)
, , . . - _ . - - , _ - . - , . . . _ - . . . , - - . - ~ . - . - - - , . - - - - . _ _ - - - . . , - , __. _
SB 1 & 2 Fe,AR TA3LE 6.3-7 (STeet 2 of 3)
STEP 7 Close the valves in the lines from the RWST to the safety injection pump suction (CBS-V47/V51).
STEP 8 Close the valves in the lines from the RWST to the charging pump suction (LCV-112 D and E). ,
The ECCS is now aligned for cold leg recirculation as follows:
.:1
- a. Both residual heat removal pumps are delivering from.the containment sump directly t RCS cold legs and are also delivering to the suction of the safety injection and charging pumps.
TQCD .
- b. Both safety injection and charging pumps are delivering to the RCS cold legs.
SWITCHOVER FROM COLD LEC RECIRCULATION TO HOT LEG RECIRCULATION At approximately 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br /> after the accident, hot leg recirculation shall be initiated. The following manual operator actions are required to perform the switchover operation from the cold leg recirculation mode to the hot leg recirculation mode.
, SWITCHOVER STEPS STEP 1 Close the residual heat removal pump discharge cold leg header isolation
- ,x ,valve n .$ (RH-V14/V26)f
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-O n t resysv91 f pgdhp psparp cyospDvfr apoly STEP Y l Open the residual heat removal pump discharge hot leg header isolation valves (RH-V32/V70).
STEP V3 Stop safety injection pump No. 1.
STEP T'/ Close the corresponding safety injection pump discharge crossover header isolat, ion valve (SI-V112).
STEP X5 Open the corresponding safety injection pump discharge hot leg header isolation valve (SI-V102).
STEP M Restart safety injection pump No. 1. ,
STEP I'/ Stop safety injection pump No. 2.
STEP Q" Close the corresponding safety injection pump discharge crossover isolation valve (SI-Vill).
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TABLE 6.3-7 (Sheet 3 of 3)
STEP h6')Close the safety injection pump discharg'e cold leg header isolation valv.e (SI-V114).
STEP )(Apopen the corresponding safety injection pump discharge hot leg header isolation valve (SI-V77).
STEP )(# Restart safety injection pump No. 2. ,
The ECCS is now aligned for hot leg recirculation as follows:
- a. Both residual heat removal pumps are delivering from the containment sump directly to the RCS hot legs and are also delivering to the auction of the safety injection and charging pumps.
- b. Both safety injection pumps are delivering to the RCS hot legs.
- c. Both charging pumps are deliverlag to the RCS cold legs.
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- TABLE 6.3-5 (Sheet 10 of 10) .
Component Failure Mode ECCS operation Phase *Effect on System Operation ** Failure Detection Method Remarks
. Residual Fails to Recirculation - hot Failure reduces re h y same method of detection l heat deliver legs of RC loops. of providing recirculation as that stated previous 1Y Su 8 removal - working fluid. of coolant to the RCS from the Conta1 ament S g to for failure of ites during pump an-P-SA injectica phase of ECCS (rump the hot lege of RC loops. operation.
Re-p-8R Fluid flow from LMSI/ Ram analogous) . pump RN-P-SA will he lost.
Mintaum flow requirements to hot legs of RC loop will be met by IJISI/Rm pump RM-P-SS recirculating fluta to RC hot lege -
- directly and via MSI/S1 Puer'=
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Lict of abbreviations and acronyms CE,CS - Charging RC - Reactor Coolant tutSI - Righ Head Safety injectica RCS - Reactor Coolaat Systes 1JESI - Low Elead Safety injectico RER, RH - Residual Heat Removal LDCA - loss of Coolant Accident RWST - Refueltag Water Storage Tank S L.
secs - Mata Control Board $1 - Safety injectica
- c WSM - Net Positive Suctice Head VCT - Volume Control Task gg tr, n.
CBS - Containment Spray B :3 tr G 4 D
- 1 4
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- SB 1 a 2 Arse ndmen t M FSAlt June 1982 TABLE 6.3-10 MANUAL SWITCHOVER SEQUENCE
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8's t l'nNikd'd RWST Time..(Sec)n ..
Duratio'n Outflow From . Tp.sn .o.c Action, *
, '_ ( S e c 7,.' , (CPM)
Start RWST lo-lo-1 signal - -
0-29 CBS-V8, -V14 opening 29 16,400 30-60 Locate CBS-V2, -V5 switches" "
30 16,400 60-75 CBS-V2, -V5 closing 15 16,400 75-105 Locate SI-V89, -V90, -V93 30 1,800
. switches 105-115 SI-V89, -V90, -V93 closing Ib 1,800 T - 45 Lo at R1 V2 , - 2 iteg 3 1 L-5 i- 21, -v 2 clesi , il
!$$=145 Locate CS-V460, -V461 switches 30 1,.800 tsc s'tc>
.1M5E95 CS-V460, -V461 opening 10 1,800 110-aca:s
-199=33 r Locate Ril-V35, -V36 switches 30 1,800
. tac >- 3 3r=>
455iis:P3* Ril-V35, -V36 opening aw-an b- /5 1,800 l M y 115 - 19,5 W4 e RH - VM sai 4ek 3C> l' '
145 -tw> KH- /14 clss n y Ib f> 5 %
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