ML20236M627
| ML20236M627 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 07/09/1998 |
| From: | Pulsifer R NRC (Affiliation Not Assigned) |
| To: | NRC (Affiliation Not Assigned) |
| References | |
| NUDOCS 9807140166 | |
| Download: ML20236M627 (34) | |
Text
a July 9,1998 LICENSEE: Commonwealth Edison Company (Comed)
FACILITIES: Quad Cities Nuclear Power Station, Units 1 and 2
SUBJECT:
SUMMARY
OF MEETING CONCERNING QUAD CITIES USE OF CONTAINMENT OVERPRESSURE On June 19,1998, the staff met with Comed to discuss the use of containment overpressure at the Quad Cities Nuclear Power Station. This meeting is a continuation of other meetings and conference calls regarding this subject. A list of attendees is provided as Enclosure 1.
The objective of the meeting was to discuss the methodology used by Comed and the results obtained for the not positive suction head (NPSH) of the emergency core cooling system (ECCS) pumps following a design basis loss-of-coolant accident. The licensee indicated that they would use the same methodology for NPSH calculations with the analysis being consistent with assumptions and criteria as approved by the NRC for Dresden. This NPSH analysis will be completed after the short-tsrm (<600 seconds) and long-term (>600 seconds) containment overpressure (COP) analysis has been completed. The new NPSH analysis is scheduled to be completed for Quad Cities by September 30,1998. The licensee stated that 3 psi of COP is required to ensure ECCS flow in the short- and long-term. The NRC staff noted that the GE
'SHEX computer code, as referenced in the licensees' presentation material, has not been
- approved except for specific cases. The licensee was requested to provide with this analysis, their applicability study for using specific Dresden analysis for Quad Cities and the GE SHEX code benchmarking used in the Quad Cities analysis.
The licensee provided a NPSH presentation reviewing the NPSH design basis, NRC inspection report follow up items, Generic Letter 97-04 response, the ECCS operability determination, and the Updated Final Safety Analysis Report and 10 CFR 50.59 safety evaluations. A copy of the presentation is provided as Enclosure 2.
ORIG SIGNED BY
. Robert M. Pulsifer, Project Manager
, Project Directorate lil-2 '
! 9807140166 990709 -
Division of Reactor Projects - lil/IV DR ADOCK 050 24 j
p Office of Nuclear Reactor Projects l
l Docket Nos. 50-254,50-265
Enclosures:
- 1. List of Meeting Attendees
' 2. Licensee Presentation cc w/encis: See next page {yj(( %:{ }hhff
\
DISTRIBUTION: .See next page g\)j ' I DOCUMENT NAME: G:\CMNTSP\ QUAD \QC0619.MTGS
' To RECEIVE A COPY oF THis DOCUMENT, INDICATE IN THE aox: "C" = COPY WITHouT Enclosures "E" = COPY WITH ENCLOSURES "N" OFFICE PM:PD3-2 6 KPp3-2 D:PD3-2 c-NAME RPulsife[ QM[n( SRichards 6k DATE 7/ 7 /98 7/ 3 /98 7/ 7 198 OFFICIAL RECORD COPY
p u ttu p 1 UNITED STATES r
j 2
NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 30046-0001
\...../ July 9,1998 LICENSEE: Commonwealth Edison Company (Comed)
FACILITIES: Quad Cities Nuclear Power Station, Units 1 and 2
SUBJECT:
SUMMARY
OF MEETING CONCERNING QUAD CITIES USE OF CONTAINMENT OVERPRESSURE On June 19,1998, the staff met with Comed to discuss the use of containment overpressure at the Quad Cities Nuclear Power Station. This meeting is a continuation of other meetings and conference calls regarding this subject. A list of attendees is provided as Enclosure 1.
. The objective of the meeting was to discuss the methodology used by Comed and the results obtained for the net positive suction head (NPSH) of the emergency core cooling system (ECCS)
- pumps following a design basis loss-of-coolant accident. The licensee indicated that they would use the same methodology for NPSH calculations with the analysis being consistent with assumptions and criteria as approved by the NRC for Dresden. This NPSH analysis will be completed after the short-term (<600 seconds) and long-term (>600 seconds) containment overpressure (COP) analysis has been completed. The new NPSH analysis is scheduled to be completed for Quad Cities by September 30,1998. The licensee stated that 3 psi of COP is required to ensure ECCS flow in the short- and long-term. The NRC staff noted that the GE SHEX computer code, as referenced in the licensees' presentation material, has not been approved except for specific cases. The licensee was requested to provide with this analysis, their applicability study for using specific Dresden analysis for Quad Cities and the GE SHEX
' code benchmarking used in the Quad Cities analysis.
- The licensee provided a NPSH presentation reviewing the NPSH design basis, NRC inspection report follow up items, Generic Letter 97-04 response, the ECCS operability determination, and the Updated Final Safety Analysis Report and 10 CFR 50.59 safety evaluations. A copy of the l presentation is provided as Enclosure 2.
l obert M. Pulsife , Project Manager Project Directorate 111-2 Division of Reactor Projects - lil/IV Office of Nuclear Reactor Projects Docket Nos. 50-254, 50-265
Enclosures:
- 1. List of Meeting Attendees
- 2. Ucensee Presentation cc w/encis: See next page l
i Quad Cities Nuclear Power Station .
Units 1 and 2 cc:
Mr. O. Kingsley, President Vice President - Law and Nuclear Generation Group Regulatory Affairs Commonwealth Edison Company MidAmerican Energy Company Executive Towers West 111 One River Center Place 1400 Opus Place, Suite 500 106 E. Second Street Downers Grove, Illinois 60515 P.O. Box 4350 Davenport, Iowa 52808 Michael 1. Miller, Esquire Sidley and Austin Document Control Desk-Licensing One First National Plaza Commonwealth Edison Company Chicago, Illinois 60603 1400 Opus Place, Suite 400 Downers Grove, Illinois 60515 Commonwealth Edison Company Quad Cities Station Manager Mr. David Helwig 22710 206th Avenue N. Senior Vice President Cordova, Illinois 61242-9740 Commonwealth Edison Company Executive Towers West lll U.S. Nuclear Regulatory Commission 1400 Opus Place, Suite 900 Quad Cities Resident inspectors Office Downers Grove,IL 60515 22712 206th Avenue N.
Cordova, Illinois 61242 Mr. Gene H. Stanley PWR's Vice President Chairman Commonwealth Edison Company Rock Island County Board Executive Towers West til of Supervisors 1400 Opus Place, Suite 900 1504 3rd Avenue Downers Grove, IL 60515 Rock Island County Office Bldg.
RockIsland, Illinois 61201 Mr. Steve Perry BWR's Vice President lilinois Department of Nuclear Safety Commonwealth Edison Company Office of Nuclear Facility Safety Executive Towers West lli 1035 Outer Park Drive 1400 Opus Place, Suite 900 Springfield, Illinois 62704 Downers Grove,IL 60515 Regional Administrator Mr. Dennis Farrar U.S. NRC, Region 111 Regulatory Services Manager 801 Warrenville Road Commonwealth Edison Company Lisle, Illinois 60532-4351 Executive Towers West til 1400 Opus Place, Suite 500 William D. Leach Downers Grove,IL 60515 Manager- Nuclear MidAmerican Energy Company Ms. Irene Johnson, Licensing Director
, 907 Walnut Street Nuclear Regulatory Services P.O. Box 657 Commonwealth Edison Company Des Moines, Iowa 50303 Executive Towers West til 1400 Opus Place, Suite 500 Commonwealth Edison Company Downers Grove,IL 60515 i Site Vice President- Quad Cities 22710 206th Avenue N.
Cordova, Illinois 61242-9740
Quad Cities Nuclear Power Plant .
Units 1 and 2 Commonwealth Edison Company Reg. Assurance Supervisor- Quad Cities 22710 206th Avenue N.
Cordova, Illinois 61242-9740 Mr. Michael J. Wallace Senior Vice President Commonwealth Edison Company Executive Towers West 111 1400 Opus Place, Suite 900 Downers Grove,IL 60515 1
l l
1 l
1
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DISTRIBUTION.
Docket File (w/ encl 1 & 2)-
PUBLIC (w/enci 1 & 2)
PD3-2 r/f (wlencl 1 & 2)
. RPulsifer(w/ encl 1 & 2)
OGC ACRS, T2E26 E-Mall S. Collins /FMiraglia (SJC1/FM)
B. Boger (BAB2)
E. Adensam (EGA1)
S. Richards (SAR)
C. Moore (ACM)
T. Martin (e-mail to SLM3)
M Branch (MXB2)
K. Kavanagh (KAK)
J. Kudrick (JAK1)
A. Levin (AEL)
T. Collins (TEC)
T. Hiltz (TGH)
M. Ring, Rlli -
1 4
\
u_._._________________________._- ________..____-_i__.____._____
MEETING HELD JUNE 19,1998 QUAD CITIES NPSH/ CONTAINMENT OVERPRESSURE NAME AFFILIATION PHONE Robert Pulsifer NRC 301-415-3016 Morris Branch NRC 301-415-1279 Kerri Kavanagh NRC 301-415-3743 Jack Kudrick NRC 301-415-2871 Alan Levin NRC 301-415-2890 Tim Collins NRC 301-415-2895 David C.Tubbs MidAmerican 319-333-8192 Roger H. Heyn Comed / Quad 309-654-2241/3075 Kevin B. Ramschen Corned /NFM 630-663-3017 l Jeffrey W. Drowley Comed / Design 630-663-7371 )
Bob Rybak Comed / Reg Services 630-663-7286 1 Doug Collins Comed / Quad 309-794-1045 (x3230)
ENCLOSURE 1
6 l
': Comed '
l l
i Quad Cities Station Net Positive Suction Head Presentation 4 to the -
Nuclear Regulatory Commission June 19,1998 l
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ENCLOSURE 2 i _
- Comed Agenda
+ Agenda
- Bob Rybak, Director BWR Licensing '
+ Meeting Objective - Bob Rybak l
+ Background - Roger Heyn, Quad Cities Design Engineer
+ NPSH Methodology- Roger Heyn
+ Conclusion - Roger Heyn l
+ Meeting Summary - Bob Rybak 5
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Comed l
bleeting Obr.ective v -
+ Review Program for NPSH Reconstitution
+ Present the Common Quad l Cities /Dresden Approach l
+ Discuss Methodology to Establish NPSH Design Basis l
l
+ Present Status of Program
+ Obtain StaffFeedback i i,
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Comed
Background
+ Review ofNPSH design basis for IEB l 96 existing strainer head loss incorrect
+ ECCS Operability Determination
+ UFSAR and 50.59 safety evaluation
+ Inspection Report 50-254/265-96020-Follow-up Item 06
+ GL 97-04 Response
+ Design Inspection Report 50-254/265-98-201 5
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Comed Review ofNPSH design basisfor IEB 96-03 - existing strainer head loss incorrect
+ UFSAR value: one foot at 10,000 gpm
+ Mark I calculation value: 5.8 ft at 10,000 gpm l
+ Head loss value based on prototypical I
testing 1
+ Existing short term NPSH calculation had negative margin - GE SIL 151
+ Long term NPSH had minimal margin with containment over pressure
+ PIF 96-3571
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Comed ECCS Operability Determination
+ Used adjusted Dresden FLO-SERIES model of suction piping and Quad discharge piping calculation.
+ Used 1996 Dresden COP analysis for short term and 1993 Quad COP analysis I for long term
+ COP analysis consistent with NP.C criteria in IN 96-55
+ Determined ECCS systems operable but degraded (COP analysis not in UFSAR) 5
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Comed ECCS Operability Determination (Continued) l Comparison of Key Containment Parameters for Dresden and Quad Cities l
Equipment / Parameter Dresden 2/3 Quad Cities 1/2 Core Licensed Power 2527 MWT 2511 MWT LPCI/RHR pump flow 4500 gpm rated 4500 gpm rated rate CS pump flow rate 4500 gpm rated 4500 gpm rated CCSW/RHRSW pump 3500 gpm/ pump 3500 gpm/ pump flow LPCI/RHR HX original 105 MBTU at 10700 gpm 105 MBTU at 10700 gpm design condition LPC1/ 7000 gpm CCSW RHR/ 7000 gpm RHRSW 165F pool 165F pool 95 F service water side 95 F service water side ,
Drywell Free Volume 158236 cuft 158236 cuft Wetwell Free Volume 120097 cuft 119963 cuit Wetwell Water Volume 112000 cuft 111500 cuft i
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Comed i
UFSAR and 50.59 safety evaluation l
+ UFSAR revised to correct strainer head i loss and reference 1993 COP analysis, GENE 637-022-0893
+ Based on 8/25/71 SER approving a few psi over pressure
+ Based on 1/4/77 SER approving short term pump cavitation would not prevent long term operation
+ Based on NRC letter to GE approving SHEX program
+ Issued voluntary LER 96-025 A
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.' Comed Inspection Report 50-254/265-96020 -
Follow-upItem 06
+ The inspectors questioned the limits on the over pressure amount used in the 50.59 evaluation, since specific values were not included in the UFSAR
+ Meeting at Quad with NRC project ;
manager on 2/18/97 to discuss bases for UFSAR/50.59 l
+ Indicated Quad would use same methodology for NPSH as Dresden 1
+ Indicated intent to complete Quad NPSH reconstituted design basis in 1997
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.' Comed GL 97-04 Response
+ Comed letter to NRC dated 1/5/98
- 90 day response to GL 97-04
+ Short term COP available assumed based on Dresden L. A.
+ Short term NPSH based on 150 F (peak pool pressure) .
+ Long term COP available based on GE 1993 containment analysis
+ Long term NPSH based on 180 F (peak pool pressure) i i
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Comed GL 97-04 Response (Continued) 1
+ RHR and CS design basis NPSH data from 90 day response to GL 97-04 The bounding case for RHR and Core Spray NPSH is the Design Basis LOCA:
ECCS Pump NPSHA NPSHR NPSH Margin (feet) (feet) (feet)
Short Term RHR 48.0 40.2 7.8 Core Spray 48.9 43.7 5.2 l
Lone Term RHR 32.6 30.0 2.6 I Core Spray 36.6 26.8 9.8 ECCS Pump Containment Containment Overpressure Overpressure Available Required (pig) (psig)
Short Term RHR 9.5 6.2 Core Spray 9.5 7.3 Lone Term RHR 3.4 2.3 Core Spray 3.4 -0.7 8
8
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Comed
~
Design Inspection Report 50-254/265 201 l + Reliance on over pressure has increased from original design
+ Comed letter SVP-98-172 to NRC 1
+ NPSH limit curves in EOP's had a few non conservative points l
+ Concern that EOP's conflicted with design basis for containment spray
+ RHR heat exchanger duty may be incorrect i
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Comed bfethodologi
+ Quad Cities Common Approach with Dresden License Amendment 1
+ Containment Over Pressure analysis l
+ Status ofNPSH design basis l
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.' Comed Quad Cities Common Approach with Dresden License Amendment
+ Quad Cities has reviewed the Dresden L. A. documentation and is using the same methods and criteria
+ Comed corporate engineering staff will review Quad design inputs and final analysis for consistency with Dresden
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Containment Over Pressure analysis
+ Short term < 600 seconds -long term >
600 seconds
+ Final analysis will be based on ANS 5.1-1979 with 2 sigma uncertainty
+ Use of GE SHEX computer program 5.
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Comed Containment Over Pressure analysis (Continued)
Comparison of assumptions used in containment over pressure analysis ASSUMPTIONS FSAR VALUES CURRENT VALUES Loss of offsite power First 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Yes, but evaluated effect if restored Diesel Generator failure Yes Yes LPCI loop select logic No Yes failure Torus water temperature 90 F and 95 F 95 F Service water temperature 95 F 95 F-Dresden sensitivity 75 F to 95 F RHR flow 5,350 gpm 5,000 gpm RHRSW flow 3,500 gpm 3,500 gpm RHR heat exchanger duty 105 MBTU/hr 97.7 MBTU/hr RHR heat exchanger Yes Yes fouling & tube plugging Drywell temperature 150 F Yes Yes
& 100 % humidity Drywell/wetwell pressure 0.0 psig/0.0 psig 0.0 psig/0.0 psig Containment leakage rate 5 % per day 0.5 % per day Pump heat included Not specified Yes Feedwater Not specified Yes Mixing efficiency between Not specified but probably 20 %
break liquid & drywell zero
)
Decay heat curve Not specified but assumed ANS 5.1-1979
- to be May-Witt Computer code GE- Unknown GE - SHEX-04 l t
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r Comed Short Term ECCSpump NPSH 1 1
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+ Piping hydraulic model uses FLO-Series computer program
+ Based on existing strainer design basis
+ Limiting failure: LPCI loop select logic
+ Design basis unthrottled flow: 2-CS 12,358 gpm,4-RHR 20,377 gpm
+ Additional pump cases evaluated .
+ Diesel generator failure limiting for RHR pumps
+ sIL-151 (3 RHR pump case) m 8
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Comed \
1 i
Short Term ECCSpump NPSH l (Continued)
Total Required ECCS Flow: Single Failure - LLS l
12000 10000 - !
$ 8000 -
c :
, j 6000 - '
l 3 f. . . .E.v.al.ua.t.ed. . . . . . . . . . . .
2000 - - --- "E"Nb ---
0 0 , , , ,
0 200 400 600 800 1000 Time (Seconds)
Total Required ECCS Flow: Single Failure - EDG l
_ 16000 I
1 14000 - " '.................... '
12000 -
f 10000 -
8000 -
] ,
3 6000 -
E
- Evaluated E 4000 -
,' Required I 2000-F 0 , . , ,
0 200 400 600 800 1000 Time (Seconds)
Peak Clad Temperature occurs at about 3 minutes
- Core Reflooded at about 7.5 minutes i
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l Short Term ECCSpump NPSH l (Continued)
Single Failure-LPCI Loop Select 30 25 p / 1 2 20 a
e 5 15 E 4 Q. i 10 ,,, ,,,, ,,, , , , , , , , ,,,_, . ._
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O m cc: 0 C:CU
-5 10 100 1000 Time (Seconds)
Pool Pressure
-s~-CS (NPSHR @ Unthrottled Flow)
O CS (NPSHR @ Required PCT Flow)
- RHR (NPSHR @ Unthrottled Flow)
Containment Pressure (Dresden Credited)
R m,
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Comed Short Term ECCSpump NPSH (Continued)
Single Failure-Diesel Generator 30 25 i l
1 3 20 I
K i 15 \ '
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^
'O 2 3 ,, . ,a :. ... -
0 :: :: OO t;;;- c ::O: 0: 53
-5 10 100 1000 Time (Seconds)
Pool Pressure
- t. CS (NPSHR @ Unthrottled Flow)
O RHR/CS (NPSHR @ Required PCT Flow) o RHR (NPSHR @ Unthrottled Flow)
Containment Pressure (Dresden Credited)
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,m. m mmm
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Comed Short Term ECCSpump NPSH (Continued)
Strainer Head Loss Comparison ,
4 Old Strainer @ yggg(yv djByro@ggjpygygigggg@a;; ppg 7ppgi, 11,133 gpm (Unit 1) gggh;fQiigs3 dgg;gi:ggj 4
New Strainer @ vn,,v .gww ,p 11,133 gpm (Unit 2) aa x x u,-;r n al hz F w e. M{y Gi;s2jfMEjipjf@r owe.
Strainer New Strainer w/ RMI #pgpipfg;. E RMI
@ 8,350 gpm
- 3fMl$;$
- = Preliminary 1 0 1 2 3 4 5 6 7 8 Head Loss (feet)
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Comed Short Term ECCSpump NPSH (Continued)
+ Summary of Key Points 1
+ Analysis consistent with assumptions and criteria approved by NRC for Dresden
+ ECCS required flow for core cooling is maintained
+ Most limiting failure for NPSH has been evaluated
+ Credited over pressure of about 6 psi would increase margin and minimize pump cavitation
+ New strainer design basis will improve NPSH margins a
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Comed Long Term ECCSpump NPSH l + Piping hydraulic model uses FLO-Series computer program
+ Limiting failure: Diesel generator l
l + Design basis throttled flow: 1-CS 4,500 gpm,1-RHR 5,000 gpm,1-RHRSW 3,500 gpm l + Non design basis flow: Additional pump cases evaluated assuming offsite power restored
+ Based on existing strainer design basis 5
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Comed Long Term ECCSpump NPSH (continued)
Single Failure-Diesel Generator 25 h 20 -
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-5 0 10 100 1000 10000 100000 Time (Seconds)
Pool Pressure RHR (Required NPSH)
-Torus Temperature M
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24 7 i + .. . ..q.4
Comed Long Term ECCSpump NPSH (Continued)
+ Summary of Key Points
+ Analysis consistent with assumptions and criteria approved by NRC for Dresden
+ ECCS required flow for core cooling is maintained
+ Most limiting failure for NPSH has been evaluated
+ Credited over pressure of about 3 psi would increase margin
+ Resolution of RHR Hx duty is expected to result in the peak pool temperature to be about the same as original FSAR value
+ New strainer design basis will improve NPSH margins l
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e Comed l Status ofNPSHdesign basis
+ Heat exchanger vendor currently evaluating Hx duty
+ GE long term COP analysis on hold pending Hx vendor analysis
+ GE short term COP analysis will be completed to validate Quad is same as Dresden
+ NPSH calculations need to be revised l after final COP analysis
+ Mark I and EQ programs are based on generic torus maximum temperature of 190 F
+ Scheduled completion 9/30/98 5
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Comed 1
Conclusion
+ Short term over pressure of about 3 psi is required to ensure CS flow l
+ Pumps will cavitate in short term and is acceptable
+ Long term over pressure of about 3 psi is required to ensure RHR flow
+ Three psi is considered to be a few psi !
I and therefore consistent with original l SER l i
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- Comed hieeting Summarv l
+ Obtain Staff Feedback l
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