ML17199Y180
| ML17199Y180 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Quad Cities, 05000000 |
| Issue date: | 05/13/1988 |
| From: | Silady J COMMONWEALTH EDISON CO. |
| To: | Murley T Office of Nuclear Reactor Regulation |
| References | |
| 4642K, NUDOCS 8806010181 | |
| Download: ML17199Y180 (22) | |
Text
..,
e Common.th Edison One First Nati laza, Chicago, Illinois Address Reply to: Post Office Box 767 Chicago, Illinois 60690 - 0767 Mr. Thomas E. Murley, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555 May 13, 1988
Subject:
Quad Cities Station Units l and 2 Dresden station Units 2 and 3 RHR/LPCI Swing MCC Modifications NRC Docket Nos. 50-254/265 and 50-237/249
Reference:
February 19, 1988 letter from J.A. Silady to T.E. Murley.
Dear Mr. Murley:
In the referenced letter and its attachments, Commonwealth Edison's preliminary plans concerning the subject modifications were described.
on March 23, 1988, Mr. Peter Kang of your staff was provided with additional information on the modifications in a conference call. Attachment 1 describes the items discussed during the call.
Also provided for your information in Attachment 2 are the results of two evaluations performed by Sargent & Lundy Engineers to address NRR questions which were originally raised during a February 5, 1988 conference call on the same subject.
A third evaluation dealing with breaker coordination will be provided
_ as soon as it is reviewed and finalized.
Please note that it is part of a broader study which has been discussed with Mr. David Butler of Region III over the last several weeks.
Please contact this office should further information be required.
Very truly yours,
.--- -=~~==-~- --~---- --,,___ ---
-~.. -*.
r:JE2~ig~n¥o~~~;~J.. :
f2t1 ~
.J. A. Silady
- ' *-*-* Nuclear Licensing: Administrator lm Attachment cc:
A.B. Davis - Reg. Admin. (RIII)
B. L. Siegel - NRR -
T. Ross - NRR NRC Resident Inspector - Dresden NRC Resident Inspector - Quad Cities 4642K
{\\no\\
t',~
ATTACHMENT 1
SUMMARY
OF CONFERENCE CALL
Subject:
RHR/LPCI Swing MCC Modifications, Dresden and Quad Cities Stations
Participants:
c. Beck -
BWR Engineering I. Johnson - Nuclear Licensing J. Silady - Nuclear Licensing P. Kang - NRR/SELB Date:
March 23, 1988
- 1.
The purpose of the telephone conversation was to provide information to *.
- Mr. Kang regarding the subject modifications.
Specifically, the principle of operation of the Swing MCC, both as presently installed and subsequent to installation of the modification was discussed in detail.
such details included which contacts and relays perform what functions, how loss of Divi~ion II DC power impacts their performance, and how the revised configuration corrects the design.weakness of c9ncern, namely that the Swing MCC cannot presently transfer in the extremely unlikely event that Division II DC ppwer were lost within 15 seconds of the Design Basis LOCA and Loss of Offsite Power.
- 2.
Also discussed was one key difference, for Quad Cities station only, between. the conceptual design,. as proposed in the S&L study report, and the detailed design, as presently scheduled for installation during the next month's outage of Quad Cities Unit 2.
A summary follows:
(a)
The conceptual design included several changes to the transfer logic, only one of which related to the concern over the MCC's ability to transfer despite loss of Division II DC power.
(b) It was initially assumed that adequate spare conductors were available, so that installation work need not include new conduit, supports, and cable.
However, the Installer's Walkdown determined that no spare conductors were available, so that a change in the project's schedule was required.
(c)
Therefore the modification was subdivided into two partial packages:
Partial A will remove one interlock in the alternate breaker's (eg #1851) control scheme, so that the MCC can transfer despite a postulated loss of Division II DC power.
This is the only action that need be taken to address the "DC Single Failure" concern.
This work is scheduled for installation. during the next Quad Cities refueling outages, __
starting with Unit 2 the Spring 1988 outage.
4642K Partial B will include the remaining contact and wiring changes, as described in the S&L Study Report.
It is expected that this work will either be installed during the two outages starting witt1 Vnit 1 next.. year, or in the alternative I this partia_l will, be determined. not to be necessary, and will be cancelled.
The 10 CFR 50.59 Safety Evaluation for Partial Modification A will include the unique considerations related to installing only a portion of the overall project, with ~the rest deferred to later outages.
SARGE.NT ~ lLUNDY lEMG:ITNJE:lElR§ FQUNDED 1691 55 EAST MONROE STREET CHICAGO, ILLINOIS 60603
( 312) 269-2000 TWX 910-221-2607 March 28, 1988 Project No. 8194-00 S&L Letter No. D514E Commonwealth Edison Company Dresden Station -
Units 2 and 3 Quad Cities Station - Units 1 and 2 LPCI (RHR) Swing Bus Mr. C. E. Beck BWR Engineering Department Commonwealth Edison Company Post Office Box 767 Chicago, Illinois 60690
Dear Mr. Beck:
Enclosed is one copy of each of the following documents concerning the above subject:
o A Comparison of the Fermi Unit 2 Design to the Dresden/Quad Cities Designs o
A Failure Modes and Effects Analysis These documents were prepared, at your request, by Sargent &
Lundy for use by Commonwealth Edison Company in response to specific Nuclear Regulatory Commission questions on the existing design of the LPCI Swing Motor Control Center and our recent modification to correct an identified design weakness.
If you should have any questions, please do not hesitate to contact me at 269-2190.
MEH:nh In duplicate Enclosures - Addressee Only Copies:
See Page 2 Your~ very truly,
-( c:_Af!f M. E. Hill Electrical Project Engineer
- ~I SARGENT & LUNDY ENGINEERS CHICAGO Mr. C. E. Beck Commonwealth Edison Company Copies:
W. B. Fancher Manager of Projects & Const. Services Projects & Const. Serv. Site Supt. (D&QC)
Station Manager (D&QC)
BWR Engineering Lead Engineers BWR Engineering Supv. Engineers BWR Engineering Site Supv. Engineers (D&QC}
R. H. Jason T. J. Ryan E. Schumacher F. W. Fischer/File March 28, 1988 Page 2
SARGENT 8c LUNDY ENGINEERS CHICAGO
.ch 7, 1988 Project No. 8194-00 Page 1 COMPARISON OF THE FERMI UNIT 2 LPCI SWING BUS DESIGN TO THOSE AT DRESDEN AND QUAD CITIES STATIONS I.
Source Configuration (Fermi, Dresden, Quad Cities)
The LPCI swing bus is normally fed from one division of 480Vac power via two in series interrupting devices.
Upon loss of this 480 Vac feed, the swing bus is automatically transferred to its standby 480Vac feed (opposite division) via two other in series interrupting devices.
Interlocking is provided to prevent a source from closing in if the bus is energized from the other source.
II.
Design Differences The existing LPCI swing bus design for Quad Cities Units l.and 2, and Dresden Units 2 and 3 is different in several important aspects from the Enrico Fermi Unit 2 swing bus design that was identified in LER #87-045-00 as having a deficiency.
The following is a discussion of the differences and the impact of those differences upon system operation.
A.
Interrupting Devices Fermi (Unit 2)
Utilizes a circuit breaker in series with a DC coil magnetic contactor from each source.
Quad Cities (Units 1 and 2)
Utilizes a circuit breaker in series with an AC coil magnetic contactor from each source.
Dresden (Units 2 and 3)
Utilizes a circuit breaker in series with another circuit breaker from each source.
III.
B.
Failure Event The design deficiency identified in LER #87-045-00 was discovered when the operator removed a DC control fuse.
The consequences of this action was that the DC coil contactor from the normal source dropped out (i.e., changed state) but the DC controlled circuit breaker in series with the contactor remained closed (i.e., did not change state).
Since both devices did not open, the swing bus went dead.
SARGENT Be LUNDY ENGINEERS CHICAGO M-~h 7, 1988 Project No. 8194-00 Page 2 This sequence of events could not take place at Dresden or Quad Cities Stations.
The existing Quad Cities Units 1 and 2 design utilizes an AC coil contactor which is powered from the 480Vac source to the swing bus instead of a DC coil contactor and the Dresden Units 2 and 3 design (as previously mentioned) only uses circuit breakers.
The AC coil contactor is not affected by interruptions in DC control power and the circuit breakers do not change state.
Therefore, the Dresden/Quad Cities LPCI swing buses would not de-energize under the above event.
Only the combination of a Loss of Coolant Accident (LOCA),
Loss of Offsite Power (LOOP) and battery failure occuring, in affect, simultaneously could prevent the LPCI system, and therefore the Emergency Core Cooling System (ECCS) from fulfilling its design objectives.
IV.
Corrective Action A.
Fermi (Unit 2)
The transfer scheme was redesigned to include a third interrupting device (i.e., a DC coil coritactor) in series with the existing breaker and DC coil contactor.
The interlock functions of the breaker are now replaced by the new contactor.
Loss of DC power causes both contactors on that feed to drop out and a transfer to the standby source is initiated.
Quad Cities (Units 1 and 2)
The Quad Cities transfer scheme was reviewed to determine if the existing interrupting devices and their control logic could be modified to function properly upon the identified condition (i.e., LOOP, LOCA, and battery failure).
Alternative designs were considered.
It was determined that a minor change in the. existing control logic would allow the circuit to transfer.
Dresden (Units 2 and 3)
The Dresden transfer scheme was also reviewed to determine if the existing interrupting devices and their control logic could be modified to function properly.
It was determined that the Dresden two-breaker design had to be altered.
The Quad Cities design fix was chosen.
SARGENT & LUNDY ENGINEERS CHICAGO V.
Advantages/Disadvantages e
March 7, 1988 Project No. 8194-00 Page 3 The Fermi Red~sign" automatically transfers from one source to the other source upon loss of DC control power irregardless of whether or not the 480Vac source is lost. Wherein the "Quad Cities/Dresden Redesign" still maintains the original operational philosophy (i.e., to automatically transfer only upon the loss of the 480Vac source).
Both "Redesigns" utilizes a double break philosophy for normal transfers.
Under a degraded condition (i.e., DC failure) the "Quad Cities/Dresden Redesign" reverts to a single break philosophy.
The Fermi Redesign" utilizes more electrical components which requires additional physical space and is more costly to install and maintain than the "Dresden/Quad Cities Redesign."
VI.
Conclusion Either of the above discussed redesigns of the LPCI swing bus would function under the given conditions (i.e., LOOP, LOCA, and battery failure).
- .).
j I
Functional Level System ECCS Subsystem LPCI Mode of RHR
Name Failure Mode Circuit Breaker #1951 Fail Closed Primary Function:
To interrupt power path from Div. II.
source to HCC 18/19-5.
Especially on an under-.
voltage condition on bus 19 (Automatic Transfer Condition).
Failure Mode and Effects Analysis Page~l~_of~_l3~-
Diagram (See* Attachment 01)
Ref. Schematic Dwgs:
4E-1373B Cause
. 4E-1681G 4E-1681B Sympto~s and Local Effects Including Dependent Failures
- Automatic transfer (on loss of Method of Detection Station.~~-Q~ua~d~C_i_t_ie_s~~~~~~~-
- *Unit~-=--=--=-~--~-=--=----'--r-#~~~
Note:
F based on AC Source Line-Up and Logic changes as shown in Attachment #1
- 2)
Analysis per IEEE Std. 352-1975 Inherent Compensating Provision Effect Upon System Remarks and Other Effects Fusing of main contacts..
Mechanism jammed.
Open circuit in trip logic.
Div. II Source - bus 19) is blocked.
Periodic Test N/A LPCI valves have power via bus 19; therefore, both Loss of* DC Control
- Power.*
Breaker 019 51 Remains*. Closed.
Automatic transfer (an loss of Div. II ac source - bus 19). 'is available.
Only 1 (ac contactor 01951) out of Breaker indicating lights if de lost
.locally. Numerous slsnns and indica-ting lights if de lost on a per bus basis or in its entirety.
Interposing relay IJHMA1951 makes auto-matic transfer function viable.
LPCI loops are available.
If bus 19 is subsequently lost, rely on auto-matic operation of redundant core cool-ing equipment (e.g.,
tvo low-;>ressure core spray systems).
LPCI values have power via bus 19 or bus 18 therefore, both LPCI loops are available.
Possible immediate detection.
2 instead of 2 out of 2 interrupting* devices are required to open in this degraded mode, to accomplish,
a source transfer.
No.
- 2.
Name Failure Mode Fail Open
!JC Interposing Fail Open Kel ay l/ln*ti\\1951 Pr imnry Function:
Sc!O!.:t*s when c i rc:11 i r breaker 01951 is open or cl~1:;cd and i r de 1*1111trol power i !;
ovnil:1blc or not.
I
/
Fail Closed Cause Shorts in wiring.
Control switch or relay failure.
Worn trip mechanism.
Arma tu re jammed.
Broken contact.
Broken wire or loose connection.
Short in coil logic wiring.
Coif failure.
Contacts shorted or fused.
Wiring fault. *Loss of de control power.
j
- I Failure Mode and Effects Analysis Symptoms and Local Effects Including Dependent Failures HCC 18/19-5 will de-energize, and then re-energize from bus 18 (auto-matic transfer) via circuit breaker
- 1851 and ac contactor 01852.
Automatic transfer of HCC 18/19-5 is blocked (since breaker 01851 cannot close).
Automatic transfer (on loss of Div. II ac source-bus 19) is still available.
Only 1 (ac contactor 01951) out of.2 interrupting devices is needed to open in this degraded mode to accomplish a source trans-fer of HCC.18/19-5 when 480Vac bus 019 is lost.
Method of Letection Inherent Compensating Provision Operator is notified that a transfer has or is occurring via breaker/contactor indicating light &
indicating lights on loads from HCC 18/19-5.
Periodic Test Periodic Test N/A N/A N/A Page~-2~_of~_l_3_
Effect Upon System LPCI valves have power via bus 18; therefore, both LPCI loops are available.
LPCI valves have power via bus 19; therefore, both LPCI.
loops are available.
If bus 19 is subsequently lost, rely on automatic operation of redundant core cooling equipment (e.g., two low-pressure core spray systems).
LPCI v<..1 I. vc s llavl:! power via bus 19 or bus 18; therefore, both LPCI loops are available.
Ri_:marks and Other Effects lmmcdinte lktl:l:l i.oi1
No.
- 3.
Name AC contactor 01952 (Ml9) includes Aux.
Contacts.
Primary Function:
To interrupt power path from Div. 11 source to MCC 18/19-5.
Especially on undervoltage condition on bus 19 (Auto-matic Trans-fer Condition).
Failure Mode I
/. ~
.. :J
§;'.
Cause Fail Closed*
Main contacts.fused.
Fail Open Mechancism jammed *.
Hot shorts in con-*
- trol wiring.
Operating coil failure.
Control relay CR19 coil failure.
- Broken wire/loose connection.
Broken contact.
Transformer
. failure.
- l
.. ~ ::. *,
Failure Mode and Effects Analysis Symptoms and Local Effects Including Dependent Failures If main contacts and/or aux.
contacts fail closed, then auto-matic transfer (on loss of Div.
II ac source - bus 19) is still available.
Either l out of 2, or 2 out*of 2 interrupting d..Vices will open to accomplish a source transfer of MCC 18/19-5.
to bus 18 when 480Vac bus 19 is lost.
If main contacts or aux. contact in TDOD circuitry fails open, an automatic transfer will take place.
If aux. contact in contactor.01852 circuitry fails open, automatic transfer (on loss of bus 19) is blocked.
Method of r.etection Inherent Compensating Provision Periodic Test Operator is notified if a transfer has occurred, via breaker/
contactor indicating lights & indicating lights on loads from MCC 18/19-5.
Operator is notified if a transfer has occurred, via breaker/
contactor indicating lights & indicating lights on loads from MCC 18/19-5.
Periodic Test N/A N/A N/A Page~-3~_of~_l_3_
Effect Upon System LPCI valves have power via bus 19 or bus 18; therefore, both LPCI loops are available.
LPCI valves have power via bus 18; therefore, both LPCI loops are available.
LPCI valves have power via bus 19; therefore both LPCI loops are available. If bus 19 is subsequently lost, rely on two LPCS systems.
Remarks and Other Effects Immediate detection.
No.
4
- 5.
Name Ac control re l.ay (CR19)
Primary Function:
Conrcol s wht::n Cont.:ict,.:i' 01952 will open or close.
Time delay relay (TDOD)
Primary Function:
Determines*
when normal source (Bus
- 19) is con-sidered lost.
Failure Mcide Fail Closed Fail Open I
I Cause Armacure jammed.
Short in control wiring.
Coif"failure.
Broken contact.*
Broken wire/or loose connec~ion.
Short 'in coil logic.
Transformer failure.
Fail Closed.
- Coil failure.
Short in wiring:
- Contact shorted or
- fused.
Transformer Failure.
,Ii,*
Failure Mode and Effects Analysis Symptoms and Local Effects Including Dependent Failures Automatic transfer (on loss of Div.
II ac source - bus 19) is still available.
MCC 18/19-5 will de-energize and re-energize from bus 18 (automatic transfe'r takes place immediately).
If. auic. "contact in breaker 01951 trip circuit fails closed, an*automatic transfer to bus 18 will.happen immediately.
'i.:*.
.1'
~,**
Method of r.etection Inherent Compensating Provision Periodic Test Operator is notified that a transfer has or is occurring via breaker/contactor indicating lights and indicating lights on loads from MCC 18/19-5.
Operator is notified that a transfer has or is occurring via breaker/contactor'.
indicating lights and indicating lights on loads from MCC 18/19-5.
. *~
l,
- N/A N/A N/A Page~-4~_of~_l3~
Effect Upon System LPCI valves have power via bus 19 or bus 18; therefore, both loops are available.
LPCI valves have power via bus 18; therefore, both LPCI loops are available.
LPCI valves have power via bus 18; therefore, both LPCI loops are available.
Remarks and Other Effects lamediate detection.
lamedia te detection.
No.
Name Failure Mode Fail Open l
Cause Jammed mechanism.
Broken contact.
Broken wire/loose connection.
Short in coil logic wiring.
Failure Mode and Effects Analysis Symptoms and Local Effects Including Dependent Failures If aux. contact in breaker 01851 close circuit fails closed, a permissive to transfer on loss of bus 19 exists.
If aux. contact in breaker 01951 trip circuit fails open, an auto-matic transfer (on lose of bus
- 19) is blocked.
If aux. contact in breaker 01851 close circuit fails open, an auto-
- matic transfer (on loss of bus 19) is blocked.
'.1
- ,1 l*,i:.
Method of Detection Periodic Test Periodic Test Periodic Test
. *, : ~
Inherent Compensating Provision N/A N/A N/A Page~-5~_of~l_3~
Effect Upon System LPCI valves have power via via bus 19 or bus* 18; therefore, both LPCI loops are available.
LPCI valves have power via bus 19; therefore, both LPCI loops are available.
If bus 19 is subsequently lost, rely on automatic operation of redundant core cooling equipment (e.g., two low-
. pressure core spray systems).
LPCI valves have power via bus 19; therefore, both LPCI loops are available.
If bus 19 is subsequently lost, rely on automatic operation of redundant core cooling equipment (e.g., two low-pressure -core -spray systems).
Remarks and Other Effects
No.
- 6.
Name Circuit breaker 01851 Pr unary Function:
Restores power to MCC 18/19-5 from Div. I source (bus 18)
Failure Mode Fail Closed upon loss.,f Fail* Open Div. II source (bus 19).
'/
/
Cause
'short.in wiring.
Control switch, or relay failure.
Broken wire or loose connection.
Broken relay or
- switch contacts.*
1 LOss of de Control
,power.
. ~;:..
Failure Mode and Effects Analysis Symptoms and Local Effects
.Including Dependent Failures Closure of breaker 01851 will cause breaker 01951 to trip open, which in turn* causes contactor 01952 to open and contactor 01852 to close; thus, MCC 18/19-5 will be'powered from 480Vac bus 18..
Automatic transfer (on loss of Div. II source - bus 19*is blocked.
Automatic transfer (on loss* of
- Div. II source - bus 19) is blocked.
. ~
'1.'
Method of Detection Inherent Compensating Provision Operator is notified that a transfer has occurred via breaker/contactor indicating lights and indicating lights on loads from MCC 18/19-5.
Periodic Test Breaker indicating lights if de lost locally.
Numerous
'alarms and indicacing lights if de lost on a per bus basis or in its entirely.
N/A N/A N/A Page~6~~of~_13~
Effect Upon System LPCI valves have power via bus 18; therefore, both LPCI loops are available.
LPCI valves have power via bus 19.; therefore, both LPCI loops are available.
If bus 19 is subsequently lost, rely on automatic oper-ation of redundant core cooling equipment (e.g.,
two low-pressure core spray systems).
LPCI valves have power via bus 19; therefore, both LPCI loops are available.
If bus 19
.is subsequently lost, rely on automatic oper-ation of redundant core cooling equipment (e.g.,
two low-pressure core spray systems).
Remarks and Other Effects Possible i.mmed ia te detection
No.
- 7.
I Name Failure Mode DC interposing Fail Closed relay OllMA1851 Primary Function:
To sense when breaker 01851 is op~en or closed and if de control power is available or not.
Fail Open
.~'
l*";
.Cause Short in wiring.
Contact failure.
Amature jams.
Broken contact.
Broken wire or loose connect ion.
- ,1*
Failure Mode and E.ffects Analysis Symptoms and Local Effects Including. Dependent Failures If aux. contact in.breaker 01951 trip circuit fails closed, breaker 1951 will trip open and an automatic transfer of MCC 18/19-5 to bus 18 will take place.
If aux. contact in contactor 11952 circuitry or aux. contact in breaker 01951 close circuit fails closed, an automatic transfer (upon loss of bus 19)- is.still available.
If aux. cont~ct in contactor 01952 circuitry fails open, contactor will open and breaker 01951 will open (when TDOD relay de-energizes).
An automatic transfer is thus initiated and MCC 18/19-5 is powered from 480Vac bus 18 *
. If aux. contact in breaker Ol952 trip circuit fails open, an automatic transfer is still available *(upon loss of bus 19).
l
.~'
Method of C;etection Inherent Compensating Provision Operator is notified that a transfer has occurred via breaker/
contactor indicating lights & indicating lights on loads from MCC 18/19-5.
Periodic Test N/A N/A Operator is notified N/A that a transfer has or is occurring via breaker/
contactor indicating lights & indicating lights on loads from MCC 18/19-5.
Periodic Test
~.
N/A Page~-7~_of~_l_3_
Effect Upon System LPCI valves have power via bus 18; therefore both LPCI loops are available.
Remarks
- and Other Effects Immediate detect~
LPCI valves have power via bus 19 or bus 18; therefore both LPCI loops are available.
LPCI valves have power via Immediate detection.
bus 18; therefore, both LPCI loops are available.
LPCI valves have power via bus 19 or bus 18; therefore,
.ho.th.LPCI..loops...are...'1ll'ailab1".
No.
- 8.
- 9.
Name Failure Mode I
Cause AC contactor 01852 (Ml8) includes aux.
contacts.
Fail Closed Short in wii:'ing.
Contact failure.
Primary Fail Open Function:
Restores power to MCC 18/19-5 from Div. I source (bus 18) upon* loss of Div. II source (bus 19).
AC control relay (CR18)
Primary.
Function:
Controls when contactor 01852 will open* or close.
- Fail Open Armature jams.
'Broken wire or loose connection.
Coil failure.
A~atin::e jams.
Broken Vire/.
,,. loose connection.
- Coil fail~re.
~*. ' **,.
- ...... J
'i
Failure Mode and Effects Analysis Symptoms and Local Effects Including Dependent Failures Automatic transfer (on loss of Div. II ac source - bus 19) is available.
If main contacts fail open, an automatic transfer (on loss of Div. II ac source - bus 19) is blocked.
If aux* *. contact fails* open, an automatic transfer is initiated and* MCC 18/19~5 is energized from 480Vac bus 18.
MCC 18/19-5 remains energized from
,41i0Vac bus 19; automat.ic transfer is blocked.
- ~.
Method of tetection Inherent Compensating Provision Periodic *rest Periodic Teat Operator is notified that a transfer has occurred via breaker/
contactor indicating lights & indicating lights on loads from MCC 18/19-5.
Periodic Test N/A N/A N/A N/A Page~-8~_of~l_3~
Remarks and Effect Upon System Other Effects LPCI valves have power via bus 19 or bus 18; therefore, both loops are available.
LPCI valves have power via bus 19; therefore, both LPCI loops are available. If bus 19 is subsequently lost, rely on automatic operator of of redundant core cooling equipment (e.g., two LPCS systems).
LPCI valves have power via bus 18; therefore, both LPCI loops are available.
LPCI valves are powered via bus 19; therefore, both *LPCI loops are available.
If bus 19 is subsequently lost, rely on automatic operation of redundant core cooling equipment (e.g., two LPCS systems);
Immediate detection.
No.
- 10.
- 11.
Name Failure Mode Fail Closed Control Fail Closed switch for breaker 01951 Primary Function:
To provide a means to manually close and open circuit breaker Fail Open 01951 from the
- control room.
Control *switch Fail Closed for breaker 01851 Primary Function':
To provide a means. to manually close and open circuit breaker 01851 from control room.*
I t
..... *1 Cause Short in wiring.
Relay contact fused.
I Mechanical failure.
Contact pitted.
Short in wiring.
Mechanical failure.
Broken wire/loose connection.
- Mechanical.failure.
Contacts pitted.
Shorts in wiring.
.. ~*
',1*.:.-'*
- *~. ~
- '*1 Failure Mode and Effects Analysis Symptoms and Local Effects Including Dependent Failures MCC 18/19-5 remains energized from 480V bus 19.
The automatic transfer function is still available.
Concact in trip circuit, if closed.
would trip breaker #1951.
This initiates a transfer of MCC 18/19-5 to 480Vac bus 18.
MCC 18/19-5 remains energized from 48ovac bus 19. Automatic transfer might be blocked.
Contact in trip circuit, if closed, would prevent a source transfer (i.e **
breaker' #1851 would close, then trip open).
I,~. ~...
Method of r.etection Inherent Compensating Provision Periodic Test N/A Operator is notified N/A that a transfer has or is occurring via breaker/
contactor indicating lights & indicating lights on loads from MCC 18/19-5.
Periodic Test N/A Periodic Test N/A
.. ~**.. ~
Page~9~~of~l_3~
Effect Upon System Remarks and Other Effects LPCI valves have power via bus 19 or bus 18, therefore both LPCI loops are available.
LPCI valves have power via bus 18; therefore, both LPCI loops are available.
LPCI valves have power via 480Vac bus 19; therefore, both LPCI loops are available. If bus 19 is subsequently lost, rely on automatic operation of redundant core cooling equipment (e.g., two LPCS systems).
LPCI valves have power via bus 19; therefore, both LPCI loops are available.
If bus 19 is subsequently lost, rely on redundant core cooling equipment (e.g., two LPCS systems).
Immediate detection.
No.
- 12.
/
Name Failure Mode Fail Open Indicating Off lights for breaker 01951 Primacy Function:
To provide positive
- indication of breaker 01951 position in control room.
'On
~'.
~
Cause Mechaoical failure,
- Broken wire/loose connection.
Age (bulb fatigue).
Broken wire/loose connection.*
Shorc*in.wiring.
Pitted contact.
... *~. *'. '
>t' Failure Mode and Effects Anal~*sis Symptoms and Local Effects Including Dependent Failures Prevents breaker 01851 from closing; thus, automatic transfer (on loss of Division II *source - bus 19) is blocked.
Ro visual indication of breaker status during and aft:er transfer to bus 18.
- Palse indication* of breaker' status when source is bus 19.
Method of r.-etection Inherent Compensating Provision Periodic Test:
N/A Operator is notified N/A if MCC 18/19-5 is energized or not by indicating lights on loads fed from MCC and can, therefore, determine (by contactor/breaker light:s) which source is supplying the power.
Operator is notified if MCC 18/19-5 is energized or not by indicating lights on loads fed from MCC and can,.therefore, de~aJ:mine (by contactor/breaker lights) which source is supplying the power.
N/A Page~_l_O~of __11__
Effect Upon System LPCI valves have power via bus 19; therefore, both LPCI loops are available.
If bus 19 is subsequently, lost, rely on redundaot core cooling equipment (e.g., two LPCS systems).
Nuisaoce Nuisaoce Remarks and Other Effects
No.
- 13.
- 14.
Name Indicating lights for breaker 01851 Primary Function:
To provide indication of breaker 01851 position in the control room.
Indicating light for con tac tor 01952 Primary Function:
To provide indication of conta'ctor 01952 position in the control room.
"'.* '~...
Failure Mode Off On Off
.. ~
I '
~..
I
'*/
cause Age (bulb fatigue).
Broken wire or loose connection.
Short in wiring.
Pitted contact.
- ~~ (bu1~* fatigue).
- . 'Broken. wire/loose con nee t ion.
- contact failure.
.,).
>.l Failure.Mode and Effects Anal1*sis Symptoms and Local Effects
.Including Dependent Failures Ro visual indication of breaker status when source is bus 19.
False *indication of breaker status *after source transfer to.bus 18.
Indicates coniactor 01952 is open when actually it is closed and source is bus 19.
Method of r.etection Inherent Compensating Provision Operator is notified if HCC 18/19-5 is energized or not by indicating lights on loads fed from HCC and can, therefore, determine (by contactor/
breaker lights) which source is supplying the p011er.
N/A Operator is notified N/A if HCC 18/19-5 is energized or not by indicating lights on loads fed from HCC and can, therefore, determine (by contactor/
'breaker lights) which source is supplying the power.
Operator is notified if HCC 18/19-5 is energized or not bY indicating lights on loads fed from HCC
- and can, therefore, determine (by contactor/
breaker lights) which source is supplying the power.
~
N/A Effect Upon System Nuisance Nuisance Nuisance Page~
11~~of~
1_
3~
Remarks and Other Effects
No.
- 15.
- 16.
Name Failure Mode Indicating Off 1 ights for contactor 01852 Primary Function:
To provide indica-tion of contactor 61852 position in the control room.
MCC 18/19-5 bus bars or power cabling Phase to phase fault' (shorts)
Primary Function:
Transmit 480Vac 3(1 power for important station services.
Fail Open Cause Age (bulb fatigue).
Broken wire/loose connect ion.
- contact failure.
Insulation failure/
damage*.
Aging/mechanical failure.
Insulation failure/
damage.
- Aging/mechanical failure.
Failure Mode and Effects Anal~*sis Symptoms and Local Effects Including Dependent Failures Indicates contactor #1852 is open llhen actually it is closed and source is bus 18.
If.failure at MCC 18/19-5 main bus, circuit breaker
- 1951 will trip open and tTansfer to bus 18 will be initiated. Circuit breaker 11851 will* close, and then trip open upon high short circuit current.
MCC 18/19-5 will be.
de-energized.
Depends on where open circuit esists (at bua or feeder circuit) as to the extent of failure.
- \\:*.
Method of l:etection Inherent Compensating Provision Operator is notified N/A if MCC 18/19-5 is energized or not by indicating lights on loads fed from MCC and can, therefore, determine (by contactor/breaker lights) which source is supplying the power.
Breaker/contactor N/A indicating lights and indicating lights on loads from MCC 18/19-5.
- Breaker/contactor N/A indicating light.s and indicating lights on loads from MCC 18/19-5.
- ,.r1.
Page~1_2~_of~_13~
Effect Upon System Nuisance Lose both LPCI loops.
Rely on automatic operation of redundant core cooling equipment (e.g., two low-pressure core spray systems).
Lo.ae portion or both LPCI loops.
Rely on portion remaining and redundant core core cooling equipment (e.g., two low-pressure core spray systems).
Remarks and Other Effects Immediate detection.
f Failure Mode and Effects Analysis Page~~l3~of--2:2.._
===============================================================================================================!:~
No.
- 17.
- 18.
Name Failiire Mode 480/120V, lQ Fail Off transformer for contactor 01952 Primary Function:
To provide source of 120V power for control log;Lc
- Fail Off Primary Function:
Cause Internal winding failure.
External short.
Internal winding failure.*
.. External' short~
To provide'source
.of 120V power for control logic circuitry of contactor 01852.
!:,_..,I.
.t*:.*
.... (,
.~**... :.;;,,. :..
- Symptoms and Local Effects Including Dependent Failures Transformer burns out.
Removes control power for contactor 01952, control relay (CR19) and t:ime delay relay (TDOD).
The consequence is an automatic transfer of KCC 18/19-5 to 480Vac bus 18.
If the transfonner fails, *automatic transfer (on loss of Div. II source - bus 19) would be blocked *
- 1 "I r..
i.;.*,*.
Method of t*etection Inherent Compensating Provision Operator is notitled that a transfer has occurred via breal<er/
contactor indicating lights & indicating lights on load from KCC 18/19-5.
Periodic Test N/A N/A Effect Upon System LPCI valves have power via 480Vac bus 18; therefore, both LPCI loops are available.
LPCI valves havepower via bus 19; therefore, both LPCI loops are available.
If bus. 19 is subsequently lost, rely on automatic operation of redundant core cooling equipment (e.g., two LPCS systems).
Remarks and Other Effects lmmedi8te detection.
- ~... -~
- .~-
~* *-
480V <DIV.ll~S 19 125V
!).1951 DIV. II N.C.
e 480V <DIV. Il BUS 18
,2-.5-V-.~!~)--1-8.. ---
D!V. l r
- N.O *.
N.O
- 1852*
SWING MCC 18/19-5..
. :*., '... -"**. -* ------~~----------------------------------41-----
~-
J - --
- -\\*-.,,*_....
I OA * *~.; :: : :,;. "
. es*:*:*,
-~ *c'..
'HMAl851 b_*:
.. I
.TRIP. I*.
I.
~----_J cs 0
TDOD
~t( **.*.*... r-.... * -....,.....-- BREAKER.1951-----t.-...,
- ~-
- *~/~ <.: >.~
.. ::*t~ -;::._.. _.--
~..
~
. TO BKR.
1951 AC LINE FEED TO.CC 18119-5 CRl9 REVISE Ml9
-D TDOD CIS SEC.>
J~
CONTACTOR 1952---~
0
(.)
0 U"I N
~
~
~
Note: Schematic Diagrams 3
have been simplified.
<QUAD CITIES-I >
cs cs cs c
ST T
.cs
- o TDOD HMA1951 b
I
. TRIP 1*.
I BREAKER 1851
-TO BKR
- b CRIS