ML20064A368
| ML20064A368 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood  |
| Issue date: | 08/24/1990 |
| From: | Hunsader S COMMONWEALTH EDISON CO. |
| To: | Murley T Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20064A369 | List: |
| References | |
| NUDOCS 9009040115 | |
| Download: ML20064A368 (9) | |
Text
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\\ Commons.oelth Edison 4
',1400 Opus Place
/ Downers Grove, Illinois 60515 1
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June 29, 1990 (Revision Dated August 24, 1990 to Correct Page 1 of Enclosure I)
Dr. Thomas Murley, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Attn:
Docunient Control Desk
Subject:
Byron Station Units 1 and 2 Braidwood Station Units 1 and 2 Cont 61nment Hydrogen Monitoring System EC_ Docket Nos. 50-453/455 and_50-15fL451
References:
(a) July 25, 1989, L.H. 01shan letter to T.J. Kovach.
(b) August 21, 1989 R.A. Chrzanowski letter to T.E. Murley.
(c) May 17, 1990 P.C. Shemanski letter to T.J. Kovach, s
Dear Dr. Murley:
Reference (a) identified a difference between tne Byron /Braidwood design of the containment hydrogen monitoring system, and the description given in the original Byron /Braidwood Safety Evaluation Report and the Updated Final Safety Evaluation Report.
The system design utilizes two containment isolation valves in series on each line with one valve powered from an ESF division 11 power supply and the other valve powered from an ESF division 12 power supply.
The Safety Evaluation Report and the UFSAR describe the design of~the system of satisfy the single failure criterion.
The difference exists if the postulated accident assumes the failure of one electrical EST division l
that would prevent the re-opening of one of the two isolation valves in each line and thus result in the loss of the hydrogen monitoring systerr..
Reference (b) provioed the Commonwealth Edison response to the NRC Staff concern.
Subsequently, Reference (c) provided the status of the NRC Staff review and a request for additional information which stated the following:
1.
"The proposed UFSAR change does not provide adequate justification for using the hydrogen recombiners (and attached analyzers) as back-up system to satisfy the post-accident monitoring criteria for containment hydrogen concentration.
Describe the degree to which the alternative system would be able to perform the intended function o' the normal hydrogen monitoring system (per Reg. Guide 1.97) in the event that the normal system was lost due to a single electrical 9009040115 900824 PDR ADOCK 05000454 0Pl P
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Dr. T.E. Murley June 29, 1990
- 1. (continued) l failure.
Indicate the actions necessary to put the proposed back-up system into operation.
Provide information detailing the reliability and effectiveness of the analyzers attached to the hyrirogen recombiners, if needed to function, and how they are affected by the operability status of emergency power sources.
Provide the basis and rationale for use of the alternative hydrogen monitoring system."
2.
" Provide the rationale for not proposing an alternative electrical.
configuration for the normal hydrogen monitoring system valves, which would ensure containment integrity and indication of hydrogen concen'..ation in the event of a single electrical failure."
l Reference (b) had provided a detailed technical discussion of the existing Hydrogen Monitoring System and concluded that the design is consistent with the--intent of the applicable regulatory requirements.
The basis for this conclusion was that no single failure would prevent containment isolation given that the probability of losing an entire electrical ESF division is very low because of'the reliability and diversity of power supplies available to.the isolation valves.
Ho,tever. Edisna_js DroDosina an BiltIna.iht_dtligR._th&.t_tatures beth CDatAlament_iselation and bydrog10 monitoting system oat _CAbility. in the event an electrical 125V de ESF divisio.D ISJ05 t_f0LlDWing_A_lO11-Qf.-CDQlant_atcident.
Enclosure I provides a detailed description of this change.
Please address any further questions regarding this mL er to this.
office.
Very truly yours, lS.C.HunsaderC. fn$m Nuclear Licensing Administrator ZNLD55/Imw:1-2 cc:
Byron Resident Inspector Braidwood Resident Inspector T. Boyce, Project Manager - NRR j
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S. Sands, Project Manager - NRR ii H. Shafer - Region III Office of Nuclear Facility Safety - IONS 1
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(REVISION DATED 8/24/90) 7
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IKLOSURLI CamportalilLEdi10R_CQWARY ByronL9r11dvsMLSlation - Units 1 & 2 Respon s_t_to_Reentilfor_AdditiontLinformailottby_the Nucitar Reaulatory r-15119tLilglC) Renardigg_the Datign_of_Containstat_Ilydrogettikal.torina Systee A.
'Deitr_lp.tton of Eds. tina _Dail2D The current design of the Hydrogen Monitoring System consists of:two mechanically independent, physically separated and redundant trains.
Separate containment piping penetrations are utilized by each train of the system.
The containment piping penetration for the suction of each hydrogen monitor is provided with two isolation valves in series (i.e, Valves IPS228A/2288 and IPS229A/2298). One of the two isolation valves on each line is powered from electrical ESF Division 11 (i.e., Valves IPS228A and IPS2288) while the other valve on each line is powered from F.SF Division 12 (i.e, valves IPS229A and IPS2298).
B.
NRC_ Concern The NRC Staff has ques'ioned whether this design meets the single failure criterion.
Specifically, the NRC Staff is concerned that failure of one electrical EST division when the valves are closed would prevent remote re-opening of one of the two isolation valves in each line and thus result in the unavailability of the hydrogen monitoring system.
In l
reference (c) the NRC Staff requested that Commonwealth Edison (Edison)
I propose a design change to the system that would ensure both " containment integrity and indication of hydrogen concentration in the event of a single electrical failure."
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PropostiBodif_tation f
i Edison has re-evaluated the existing Hydrogen Monitor hv System design and proposes to implement a moJification to resolve the NRC Staff concern.
The existing design will be revised by replacing the operator for one of the two containment isolation valves in each line with an operator that falls open upon a loss of power.
The affected valves will be the Division 12 (22) valve in the Division 11 (21) hydrogen monitoring line h
(Valve 1/2 PS229A) and the Division 11 (21) valve in the Division 12 (22) hydrogen monitoring !ine (Valve 1/2 PS228B).
-(Attachment A is a marked-up copy of PLID H-68, Sheet 7 that identifies the. valves affected by these proposed changes for Byron Unit 1, as an example.) A similar
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change is proposed for Byron Unit 2 and Braldwood Units 1 and 2.
This i
new design provides for two hydrogen sample lines each dependent on a
. single-ESF division's power to perform its samnling function.
At the same time, the containment isolation function san be achieved for both l
lines with only one operable EST division. Attachment B provides advanced marked-up copies of the revisions to the UFSAR pages which would result from this modification.
The proposed modification will ensure availability of the Hydrogen Monitoring System in the event of a loss of one electrical 125 Vdc ESF division.
Two separate Class IE power supplies will still be utilized to power redundant containment isolation valves in series.
D.
hnplementatino Edison has scheduled the implementatior, of the above modifications at the next convenient refueling outages.
All modifications are scheduled to be-completed not later than the end of the following refueling outages:
Sept, 1991 BIR04 Byron Unit 1 Cyron Unit 2 Jan, 1992 B2R03 Braldwood Unit 1 Sept, 1992 AIR 03 Braldwood Unit 2 Sept, 1991 A2R02 in the interim, continued plant operation is justified based on the technical discussion presented in Reference (b).
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MRQRlpflA101000_ STAT 10ll!. UNITS 1 & 2 i
ULSAR_CHAllGULBASEELQK.fnQPOSED
' IWDILICaI10fL10EDROKILifDilUDRillG_SISIDI IEAGES 6.2-199 _512-2002_E 34-Il l
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a 8/B-UFSAR TABLE 6.2-58 (Cont'd)
TYPE C l
l VALVE RACA-LEAR DISTANCE 70 GDC PEWETnA-LINE ISOLATION TIOS (INSIDE TEST OUTE85EOST I
mEQUIRE-7 TOW SIZE ESSEN-REFERENCE VALVE OR OUTSIDE (YES
. ISOLATION WALVE SYSTEM.NAME IIET.Mt.T
_pUMBER_ ftUgD (in.) TIAL!_ _pptAWi pG.,.
,_.vnetit__ C0lrTAINIENT) ' OW_p01 Y88,TE d(t)_ TYPE _
f.
f Off-Gas 56 13 Air bH2 3
YES M-47 2 IOG079 Inside YES N/A Dut Fly S.
13 Air & H2 3
YES M-47-2 IOG000 Inside YES W/A Det. Fly 2
56 23 Air & M2 3
YES N-4 7 -2.
IOG001 Inside-YES W/A Det. Fly 56 69 Air & H2 3
YES N-4 7-2 IOG657A Inslee YES ss/A Det. Fly 56 13 Air 6 M2 3
YES M-47-2 IOGOS2 Outside YES 981 5.
Set. Fly l
56 69 Air & H2 3
YES N-47-2 IOG683 Outside YES tels.
Set. Fly i
56 13 Air 6 M2 3
YES N-47-2 IOGOS4 Outside YES Mtu.
Det. Fly i
56 23 Air 6 H2 3
YES N-47-2 IOG005 Outslee' YES stIN.
Det. Fly J
Process Radiation 56 52 Air 1
M-78-10 1P9001A Outslee YES 1.4
. G.otm 56 52 Air 1
N-78-19 IFROGIS Outside YES 3.5 Globe 56 52 Air i
N-78-le-179066 Outside YES 2.3 Globe i
l 52 Air 1
N-78-IS IPRG32 Inslee YES N/A Check i
56 AL Air 2
M-70-6 1P9933A Outslee YES MIN.
Globe i
56 AL Air 2
N-78-6 1799333 Outside YES Nte.-
Globe i
56 AL Air 2
N-78-6 Irace2R Outside YES sets.
Globe 56 AL Air 2
N-70-6 IPW992G Inside YES W/A Check e
56 AL Air 2
N-78-6 IPR 033C Outside YES IIIW.
Globe 56 AL Air 2
M-78-6 IP99339 Outside YES 958 9.
. Globe I
56 AL Air 2
N-78-6 1PR602F Outslee-YES N15.
Glete 56 AL Air 2
N-70-6
.1P99925 Inside YES W/A Check j
Hydrogen Monitor 56 45 M2 + Alr 1/2 N-68-7 IPS228A Outslee -
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' 951W.
Globe-I u
45 Ws + Air 1/2 N-68-7 IPS229A OutSide 1ren '
N15.
Globe 5612(BY)45(88ti M2-+ Air 1/2 N-68-7 iPS23GA Outslee YES 951 3.
Globe 5612(SY)45(SW) tog + Air. 3/4 M-68-7 IPS231A Imolde
-YES N/A Check 56 36 _,1$, e Air I/2 N-60-7 1P52295 Outside YES sets.
Globe 56 36
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- Air 1/2 N-68-7 IPS2293 Outslee YES Nte.
Globe 5631(sY)36(SW) 562 + Air 1/2 N-64-7, 1752399 Outside YES 955 5.
Globe 5633(SY)36(Saf)
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- Air 3/4 N-68-7 IPS2318 Imelde YES N/A Check 6
6.2-199 REVI5 ION 1 - DECSIWER 1999-
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FRIMARY ARY
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POST-POWER CIDSURE ISOLA-ISOE OF N00E OF WALVE CDC VALTE R20tsteE-Orts-possuhL searTDona ACCIDENT FAILURE T 894E*
- TION ACTUA-ACTUA-FUesER Cogsgr gco.
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l EISTM_EggE 1531_1E7 AIDL E9511195 2951T195 MTim E951 TIM _(secl_ SIGINES _I308. _TIcel__
SOUSCE Off-Cao 56 50 0 Closed Closed Closed As Is 60 T
A ges gE I
56 310 Closed Closed closed As Is 60 T
A set IE 56 sep Closed closed Closed As is 6e T
A see 3E 56 38 0 Closed Closed
. Closed As Is 68 7
A set 3E 3'
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56 IED Closed Closed Closed As Is 60 T
A gue -
IE I
36 se Closed closed Closed As Is 6e T
A am 3g 3
set IE I
i 56 500 Closed Closed Closed As Is 68 T
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l 56 peo Closed Closed Closed As to 60 T
A gue 3g l
Proceso mediation 56 AO/S Open Closed Closed closed 4.5 T
A nog IE e
56 AS/S Open Closed Cleoed Closed 4.5 T
A.
pas IE e
56 A0/5 Opem
'Cleoed closed Closed 5.0 7
A sus IE 6
i 56 N/A N/A N/A N/A N/A N/A 5/A W/A N/*
9/A 6
56 N
Cleoed Cleted Closed 9/A W/A N/A 5/A N/A N/A
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56 38 Cleoed Closed Cleoed W/A W/A N/A prA g/A m/A 56 II Cleoed Closed Cleted 9/A W/A 9/A m/A m/A m/A 7
t 56 N/A N/A N/A-5/A 5/A N/A N/A 5/A N/A m/A 7
l 56 gI Cleoed Closed Cleeed W/A N/A W/A s/A m/A s/A f
56 II Cleeed Closed Cleeed N/A N/A W/A N/A s/A se/A 56 58 Closed Closed Cleeed WA S/A W/A N/A g/A g/A 7
56 N/A N/A W/A 5/A N/A N/A N/A W/A W/A N/A 7
f Mydrogen stonitor 56 3
Open Closed C;osed As Is 5
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Open-Closed Cleoed guemeek 15 7
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Cleoed
.Closee cuesee Cleoed
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5/A S/A N/A 5/A W/A N/A N/A N/A 36 8
Osee Cleoed Cleemd dommee%
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56 S
Open Closed C5_'
As Is-15 T
A me IE I
56 8
Cleoed Cleoed Cleoed Cleoed 15 T
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6.3-399
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l B/B.UTSAR as ANS! 831.1.
The paping from the containment to the first isolation valve will be designed to the requirements of SRp 3.6.2.
Operation of tne hydrogen monitors is independent of the hydrogen recombiner since both systems used separate piping and contain-ment penetrations and are not dependent upon the other to operate in any way.
The hydrogen monitoring system consists of two inde-pendent, physically separated and redundant subsystems and, thus, meets the single failure criteria.
Separate piping penetrations of the containment are utilized by each train of this system.
Each train's hydrogen monitor discharge containment isolation
% valve J.ES_210A/mi and one'of two series inlet containment ~~ola-fg Tion valves 6"S115'f D e re powered f rom se >arate 35 sourc%.
The 4g pecond inlet-cohtM nment isolation valve (T C. 4 is powered 1
'from the alternate power train,9 f Pss296/n9A l _s_-s Byron /Braidwood stations reet the requirements for continuous indication in the main centrol room with IEEE 323-1974 qualified indicators.
The eenitors may be controlled from the control trom, sAMptr coNDIT!0NINO The Model 225CM monitoring system is designed to monitor contain-ment gas for percentage ey volume of hydrogen (dry analysis).
The operating range is -5 to +50 psig, 40'T to 445'r and relative.
humidity from 10 to 100%.
A sample of the containment atmosphere will be taken at or near one of the containment penetrations and another approximr.tely 180 degrees away on the other side of the containrent.
The sarples taken are representative of the contain-ment at.osphere due to the rixing system effects, which is dis-cussed in Subsection 6.2.5.2.3.
Radioactive sample gas is drawn from the containment vessel by means of a sample pump into the analysis unit precooler where it is lowered from temperatures as high as 445'r to ar.bient temperature of the analyzing unit.
A solid state self-regulating thermoelectric cooler further reduces the gas terperature to below analysis unit ambient; after which 0.4 scfh of sample gas is directed to the sample measuring cell maintained at 170'T.
Atter the gas passes through the cell, it i s returned to the containment via a pressure regulating network which maintains pressure above containment assuring return of the sample gas.
Any condensation formed in either of the coolers is gravity drained to a water trap which is automatically purged back to the containment with the aid of the pressure regulating network.
CALIBRATION Instrument calibration is performed by actuating the appropriate solenoid valve directing zero or span gas with a known concentration througn a f1:w controller and into the cell.
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& on Valves PS228B and PS229A are designed to fail open Isolati on loss of power.
Thus failure of one of the lE electric power sources will disable only one train of the hydrogen monitoring
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N E.30-7 REVI S 1'ON 1-DECEMBER 1989 l
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,f Docket Nos. STN 50-454, STN 50-455 STN 50-456, STM $0-457 Mr. Thor:s J. Kovach Naclear Licensing Panager Commonwealth Edison Company-Suite 300 OPUS West 111 1400 OPUS Place Downers Grove, Illinois 60516 Dear Mr. Kovach
SUBJECT:
BYRON STATION, UNITS 1 AND 2, AND BRAIDWOOD STATIGN, UNITS 1 AND 2 - REQUEST.FOR ADDITIONAL INFORMATION, CONTAINMENT HYDROGEN MONITORING SYSTEM DESIGN (TAC NOS. 74547, 74548, 74549 AND 74550)
The enclosed Plant Systems Branch request for additional information concerns d
Comonwealth Edison's submittal dated August 21, 1989, regarding the discrepancy between the exis'ing Byron and Braidwood designs for the containment hydrogen monitoring system, and the designs approved in each plant's original Safety Evaluation Report as described in the Updated Final Safety Analysis Report. We fino additional information from Ceco is necessary for us to continue our review.
You are requested to provide the additional information (see enclosure) within 45 days of receipt of this letter.
The reporting and/or recordkee;,.ng requirements contained in this letter affect fewer than ten responderts; therefore, OM8 clearance is not required under P.L.96-511.
Sincerely, (V
Paul C. Shemanski, Project Manager Project Directorate III-2 Division of Reactor Projects - III, IV, V and Special Projects Office of Nuclear Reactor Regulation
Enclosure:
As stated cc w/ enclosure:
See next page
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Mr. Thomas J. Kovach.
Byron /Braidwood Power Station
' Cosmonwealth Edison Company Unit Nos. I and 2 CC:
Mr. Gabe Toth U. S. Nuclear Regulatory Cosmissia Westinghouse Electric Corporation Byron / Resident Irspectors Office
?nergy Systems Business Unit 4448 North Geman Church Road Post Office Box 355 Bay 236 West Byron, Illinois 61010 Pittsburgh, Pennsylvania 15230 Ms. Lorraine Creek i
Joseph Gallo, Esq.
Rt. 1, Box 182 r
Hopkins and Sutter Manteno, Illinois 60950 888 16th Street, N.W.
t Suite 700 Mrs. Phillip B. Johnson Washington, D.C. 20006 1907 Stratford Lane Rockford, Illinois 61107 Regional Administrator V. S. NRC, Region 111 Douglass Cassel, Esq.
799 Roosevelt Road, Bldg. f4 109 N. Derarborn Street Glen Ellyn, Illinois 60137 Suite 1300
~ ~
Chicago, Illinois 60602 Ms. Bridget Littis Rorem At W seed Coordinator David C. Thomas, Esq.
117 North Linden Street 77 S. Wacker Drive Essex, Illinois 60935 Chicago, Illinois 60601 Mr. Edward R. Crass Michael Miller, Esq.
Nuclear Safeguards and Licensing Sidley and Austin l
Division One First National Plaza l
Sargent & Lundy Engineers Chicago, Illinois 60690 55 East Monroe Street Chicago, Illinois 60603 George L. Edgar Newman & Holtzinger, P.C.
U. S. Nuclear Regulatory Commission 1615 L Street, N.W.
s Resident inspectors Office Washington, D.C.
20036 l
RR#1, Box 79 Braceville, Illinois 60407 Commonwealth Edison Company Byron Station Manager i
Mr. Thomas W. Ortciger, Director 4450 North German Church Road lilinois Emergency Services Byron, Illinois 61010 and Disaster Agency 110 East Adams. Street J
Springfield, Illinois 62706 Illinois Department of Nuclear Safety Office of Nuclear Facility Safety 1035 Outer Park Drive Springfield, Illinois 62704 l
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Enclosure REQUEST FOR ADDITIONAL INFORMATION PLANT SYSTEMS BRANCH
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WSED REVISION TO THE UFSAR INCORPOPATING THE LW 10 DESIGN FOR THE HYDROGEN MONITORING SYSTEM BYRON STATION. UNIT NOS. 1 AND ?
BRAIDWOOD STATION, UNIT NOS. 1 AND 2 1
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1.
The proposed UFSAR change does not provide adequate justification for using the hydrogen racombiners (and attached analyzers) as 4 back-up system to satisfy the post-accident monitoring criteria for containment hydrogen concentration. Describe tile degree to which the alternative system would be able to perform the intended function of the normal l
hydrogen monitoring system (per Reg. Guice 1.97) in the event that the nomal system was lost due to a single electrical failure.
Indicate the actions necessary to put the proposed back-up system into operation.
Provide information detailing the reliability and effectiveness )f t. I analyzers attached to the hydrogen recombiners if needed to fur.ction, and how they are affected by the operability status of emergency power Provide the basis and rationale for use of the alternative l
sources.
[
hydrogen monitoring system.
2.
Provide the rationale for not proposing an alternative electrical tonfiguration for the nomal hydrogen monitoring system valves, which 1
would ensure containment integrity and indication of hydrogen concentration in the event of a single electrical failure.
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