ML17193B487
| ML17193B487 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 06/12/1981 |
| From: | Rausch T COMMONWEALTH EDISON CO. |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML17193B488 | List: |
| References | |
| TASK-06-07.C1, TASK-07-03, TASK-6-7.C1, TASK-RR NUDOCS 8106180363 | |
| Download: ML17193B487 (11) | |
Text
{{#Wiki_filter:* . Coinmonwea.Edison B One F.irst National Plaza, Chicago, Illinois Address Reply to: Post Office Box 767 Chicago, Illinois 60690 June 12,
- i,,
d Dennis M. Crutchfi~ld, Chief Operating Reactors Branch #5 Divisi~n of Licensing u~s. Nuclear Regulatory Commission Washington, D.C. 20555
Subject:
Dresden 2 SEP Topic VI-7.C.l, Appendix K - Electrical, Instrumentation and Control (EIC) Re-reviews and VII-3, Safe Shutdown Systems NCR Docket 50-237 Reference a: Dennis M. Crutchfiel~ letter of March 11, T98l to J.S. Abel
- c*
Dear Mr. Crutchfield:
Commonwealth Edi~on h.as reviewed the above referenced document. Many of our co mm en ts were d i s.*c us s e d w i th your st a f. f du r i n g t e l e p h o n e c o n v e r s at i o n o n A p r i l l 5, l 9 8 l. D u r i: n g t h e c a l l t h e re.w a s a general discussion of the VII.-3 topic report which the staff stated they. would work on-to address Edison's general areas of concern. Edison's specific comments on the VI_ -7.C. l topic report are as follows: l) Page 4 - Section d and last paragraph - The~~ pa~agraphs address issues bei~9 handJed by the fire protection r e v i e w. T h e s e p a r a *g r a p h s:
- s h o u l d
- i n d i c a t e t h a t t h e f i r e protection resolutibns, when they are finalized will be the appropriate action for resolvi.ng any open items.
- 2)
Page 6 - Last paragraph - There appears to be confusion con~erning the redundancy of the 120V A.C. essential service bus*.* The name of this bus is a hold over from the fossil stations when a highly reliable bus, in this case to~ the process comp~ter, was required. The required safety redundancy comes from.the i~strument bus. The problem of loss of the essential service bus was addressed by I
- E. Bu l l et i n 7 9 - 2 7.
E.d i son 1 s response to _ the bu l let i n was submitted by D.L. Peoples* letter of February 28, 1980 to James G. Keppler. Attachment A_to this letter is the February 28, 1980 submittal letter and the Dresden Units 2 and 3 attachment to it. 3 ) P a g e 7 - F i r s t -P a r a g r a p h * - T h e i n s t r um e n t b u s r e d u n d a n c y comes from the essential servi~e bus. See the discussion/l-?r-in item 2 above. Attachment A,.Edison's response to ~~ I
- E
- B u l l e t i n 2 9 - 2 7, a rs b
- a d d r e ss e s t h e i n s t r u m e n t b u s.
.S 13,;~uP.e n *f+ -1 /) ..S~ 0HA""';.. S1 +.. \\ 1/( s106i.soJ~1 r J~.
D. June 12, 1981
- 4)
Page 8 - Section 2a - 480V switchgear bus 25 is not safety-related nor divisionalized. The bus has no safety-related equipment on it.
- 5)
Page 8 - Section 2b - Comments from item 4 apply. Interlocks in the close circuit of bus tie Breaker 25-26 prevent paralleling Buses 25 & 26 while both buses are energized. There are also interlocks in 'the close circuits of Bus 25 and Bus 26 main feed breakers which prevent closing if bus tie Breaker 25-26 is closed. These interlocks are shown on Drawings 12E-2347 & 12E2348 (aperture cards enclosed).
- 6)
Page 8 - Section 2C - Comments from item 4 apply. With loss of offSite power, Buses 25 and 26 are automatically dropped. After the diesel generator is started the operator must first manually load 4KV Bus 23, manually load bus 25 and then manually load bus 26. Procedures govern how the operator will operate for a given situation.
- 7)
Page 9 - Section 3 - See comments 4 thru 6.
- 8)
Page 10 - Section 8 - The automatic transfer requires operation of two breakers in series. Interlocks are provided that prevent automatic transfer in the event of a single failure. (Reference Drwg. 12E-2347).
- 9)
Page 11 - Section 10 - 480V MCC-25-2 is a balance of plant bus. It is not intended to be either safety-related or divisionalized.
- 10)
Page 11 - Section 12 - In the event that the DC output breakers of both battery chargers were closed, Div. I and Div. II AC power sources would supply a common DC load. However, the 2 AC breakers and 2 DC breakers per charger plus the isolation characteristics of each charger provide isolation and separation of AC power sources. There is no direct connection of AC power systems. An interlock would be required if redundant AC power feeds supplied one battery charger.
- 11)
Page 12 - Section 13 - Edison concurred with the staff. Additional electrical isolation has been provided via the installation of normally open disconnects at the reserve bus end of the main/reserve cable tie.
D. June 12, 1981
- 12)
Page 12 - Section 15 - See comment 12.
- 13)
Page 12 - Section 15 last paragraph. When offsite power is lost the diesel generators start-up. For a few seconds the diesel generators require the batteries. After that the diesel generators supply the battery chargers and the possible overloading situation disappears. Once the diesels are running they are self exciting and do not require the battery.
- 14)
Page 13 - Section 16 - The breakers referred to in this section are molded case breakers and are not of the type which can be racked out, they can only be placed in the open position. During a plant walkdown in response to this concern it was determined the plant operates with the removable link removed when the b~eaker is open.
- 15)
Page 14 - Section 18 - Edison has reviewed this item. This item will be resolved by making the auto-transfer a manual-transfer. A modification will be issued to remove the automatic transfer scheme for DC loads in the 345 KV switchyard.
- 16)
Page 14 - Section 19 - The worst condition would be a fault on the circuit feeding the D.C. 2/3 load. For a fault at this location to have an effect on the unit 2 l25V D.C. system two breakers would have to fail. For this failure to propagate to unit 3 125V D.C. system after the unit 2 l25V D.C. system has had multiple failures the load must transfer to Unit 3 and two more breakers would have to fail. After the staff reviews drawing 12E2322 rev1s1on P and 12E3322 revision N and the single failure design criteria, Edison believes the staff will find this scenario to be extremely unlikely.
- 17)
Page 15 - Section 23 The comment on this section is the same as item 15 above.
- 18)
Page 16 - Section 26 - Comment 17 about section 19 are applicable to this item also. In addition, the automatic depressurization loads are also fused with 20 Amp fuses.
- 19)
Pages 16 thru 19 - Section C - This section deals with fire protection issues and should be deferred to the fire protection review.
- 20)
Pages 19 thru 21 - conclusions - T~ese items should be modified to reflect the above comments.
D. June 12, 1981 Please address any questions you may have concerning this matter to this office. One (l) signed original and thirty-nine (39) copies of this transmittal letter and attachment have been provided for your use. One(l) aperture card of drawings 12E2347 and 12E2348 and six(6) copies of drawings 12E2322 and 12E3322 have also been provided for your use. NPS/vhs Ol90a cc: RIII Resident Inspector, Dresden Very truly yours, Y/f{~ T.J. Rausch Nuclear Licensing Administrator Boiling Water Reactors
e Commonwealth Edison One Fors! National Pl31J. Ch*CJCJO. Illinois Address -Reply to: Poslc5ii;(;-~ 8-c:i-;-767 Chicago. Illinois 60690 !,,I. James G. *Keppler, Director Directorate of Inspection and Enforcement - Region_III U.S. Nuclear Regulatory Corrunission 799 Roosevelt Road Glen Ellyri, IL 60137 February 28, 1980
Subject:
Dresden Station Units 1, 2, and 3 Quad Cities Station Units 1 cind 2 Zion Station Units 1 and 2 Resp::>nse to IE Bulletin 79-27 Concerning Loss of InstrLUTientation and Control Power Buses NRC Cocket. Nos. 50-10./237/249,
- *so~254/265, *and*so~295/304
- Reference (a)_::*-~*.. -~* Kepple_r letter ~() ~~ -~~ed dated November 3q, __ ~979 Reference (a) transmitted IE 8ulletin 79-27, which, requested a resfDnse in ninety days to concerns relating to loss of non-Class I-E instru-mentation and control pJWer system buses during operation.
o..i~ resp::>nses for Dresoen Unit 1, Dresden Units 2 and 3.,., (luad Cities Units l and 2, and Zion Units 1 and 2 are contain_.od in attachments 1, 2, 3 and 4, respectively, No rrodifications, except for those already in progress at Dresden i, are deemed to be necessary based on the reviewes of existing installations at Dresden, Quad Cities, and Zion, Please address any aditional questions you may have concerning this matter to this office, I.* Very truly yours, l (! ./.. __.,!. D. L. Peoples Director of Nuclear Licensing cc: Director Division of Reactor*-- ~ Operations Inspection --~\\ ~ 1if -.-.. -- - -.. ---- *--"_--*--*-- -- --~~-- - *-, ---.
:---'--*()'
100J'J..DO --*-~. - : *:-. -*---- -. ---- :-:-_-:=._:.:;1
.. AT'I'ACHl'iENT 2 DRESDEN STATION UNITS 2 AND 3 *
- 1.
Based on review of this bulletin, the follow~ng buses are addressed in this response to the bulletin for both units: Instrument Bus 24/48 VDC Buses A and B Reactor Protection Buses A and B Essential Service Bus Instrument Bus The 120/240 VAC instrument bus is nonnally fed from.MCC 28(38)-2, with.* tii..e reserve supply from MCC 25(35)-2. There is a normal seeking auto-matic transfer switch to MCC 25(35)-2 if normal power -is lost.. A: Control Room alarms are:
c~-_-... _:**:.:
- .- =~ *'---*-*-" -.- =.: __ *--..~.*~.-~-"-:*,~..,,_~:_,c-_.:.:.;:- -*-,::~:.*~\\
- 1) 120 VAC Instrument*_.B_u~_:..T~a11sfer to Enie~~~~cy Su.pply..
'.=.-:-:::::~.=/:f:_::-:*-::;;~_: ~0 *--* :--~
- 2) 120 VAC Instrument B.us** Low Voltage Bu5 voltage indication is available in the Auxiliary Electrical Equipment Room'. :**Other**a:.iarms -that would come. up if_ the instr.ument ous was _lost are:
- 1) 24/48 VDC Battery Trip
- 2)
Moisture Separator High Level
- 3)
Ma.in Steam Drain Tank High Level
- 4)
Heeter Drain Valve Closur~ B. The following loads are connected to the instrument bus: Panel 902(3) Off Gas Panel 902(3) HPCI Panel Panel 2202(3)-16 and 20 - Accumulator monitor Panel 902(3)-:-4_ and 5 - Control Room panels - ~ -....... -- Panel 902(3):-11 -., Area'. r~dlatio-;:~ ~*:>riltors~::.. ~;~~'.~)j{~~:~~~:~:/;:.-:::~>~~:*:;.:=--~~~..,.-,--:* *_ ~:: . Panel 902(3)-18 Reactor._ system process instrument: power supply -__ - :\\ --. ~ ~. *~ ~*: *~~.~:~*~ 'an~_ 2202 (3)-25:A *ar:~* 258._*.-_r:~c~:~-~:_<.-M-~ - set-:-.-.*~:\\-.-~-***.::~_~"=::-,:*:--~~=:'.'~~ Panel 902(3)-19 :-=- CRD.instrument~:- 6rocess~*1_n~!?_trufuent::-:=:-~-:=-:- -:~<.:~~:,::~-~-=~-...;..-. -_ ::.-/:::;
I
- 1.
B. (Continued) Panel ~02(3)-19 and 902(3) Jet *pump_ and RPV lev~l,:_pressure 'o:- *,.~:.:.. :ii*, -* * -~--:~.*:: temper-~f~-i=e-- 1~~ tr;:i;;;e~-tat ion_"-*~ **_* __,:: :-.J~,-~c:-~::~=-;.c: Panel 902(3)-6, 7, and 8 - Main control board, instruments, and recorders Panel 902(3)-6, 7, 8 and 2252(3) Main generator vol:age regu-lator cubicle recorders and instrumentation Panel 902 (3) Annunciator input relay, D.C. supply failure alarm Panel 902(3)°-28, 40 - Reactor manual control Panel 902(3)-3, 4 - Test and pilot solenoid valves, isolation valves Panel 902(3)-32, 33 - ECCS relay, test check valves 140~-9A, 1501-25A Panel 902(3) EHC cubicle .Panel 2202_(3)-14.-:: SRM/IRM drive control, 2252(3)::-30,~48.. local P.a:nel _:__... -~~-~- .~=- - -. __ :.. ~ .. :..::::... :-.: :._;_:-*::.. *~.. -:-:;:.... ~- Master stati9n supervisory cabinet 24/48 VDC neutron monitor battery chargers 125 and 250 VDC battery ground detector recorders Loss of the instrument bus would cause a loss of feedwater heater level control. The normal drains would fail closed and the ex-traction steam dump valves will open. The moisture separator level would rise, and a *high moisture separator level turbine trip and a*reactor scram would occur. Feedwater controllers, regulating valves; narrow range Yarway level indications~ power level indication, and rod *position indi"'." _ ca.tion would oe operable. The abov~ indications would be suffi-cient to verify the scram. The loss of the 24/ 48 VDC battery cft.argers :is.of:minimal,concern since the? battery is sized to main-tain',_t]le.9-~-~-~or_. eigh~ __ hour~.... 'fy_e f_o_l!g~i_ng *indications would be
- -*-~:-_-_..
last:.... ~- _feedwater.. regulating_ valve. p-oSi tion,*.::.fe.edWater _f~ow ~ -Ste3m * * *---_. -.... ~ . * *.... **::~*-:;-,:-~.--.flow,::-cE:r1A~ _reactor water le_v~l, core.. spray,,Jlow,, core_ sp_:i;~y**.i:>~~~~~:,.. ~:2~*S'?fj ..,..:..:..*_,..;_;...,,-
- sure, wide-range -reactor water... levels,: M-G-*set *temperatures, CRD -*
- -;~*.;.:;~:~~
pressure* CRD.flow, jet pump flow,.recirc':.:pump.flow,.recirc. pump ____ :.::~-:*.:*.DP,=~<::~e~n~~_-flo~ ~ cle~_ryu~-~ t-C~~!J~rat~re-~-~~r~ci r~:_-,~:-Pun:1p s~-a~- p:~es~~~~-~~-:=~~~:*i.:5 suppression chamber pressure, suppression chamber level, r -circ. -:. * *:-:'-*c~:='
- **::-*: ~': * -- pump -temp.erature;*- cleanup-conductivity-,- ancf_c!r:~~lJ* PSe.~s.~_!"e. ~-The~--~:-~_",;.=-..:i
.. -:*_-~*-,. **.: - -~ *::: --:.. --- ... *----~----.-..... ____,. __ *-----.*--.. ;..;.... -.. -*.--*-_.,_
- _*----***-:*~---
-~ -~-~--~--:~
- 1.
B. (Continued) TIP ball __.valves,. wo_ul __ d close, SBGTS trains would start; and the reactor_ building ven-tilation "would isolate;~* *.Th*e* reactor build-.. ing to suppressi~n.ch.amhe"I: vacuum breakers w;;-ufd open; however, the check valves would prevent venting the suppression chamber to the reactor building. Placing and maintaining.the reactor in a cold shutdown condition may still be accomplished due to the availability of normal feedwater flow, shutdown cooling, ECCS, and the main condenser.. Also, the Yarway level instruments would be available to closely monitor reactor water level. Other loads that would be lost are of no significance in placing or maintaining the reactor in cold shutdown. C. No modifications are proposed based on the above review. 24/ 48 VOC Buses A. The 2(3)A and 2(3)B distribution panels are supplied by.the 24/48 VDC batteries,* rated at 80 amperes hours, and battery chargers. There is an alarm in the Control Room for battery unde:-:-v'oltage. Loss of the 24/ 43* VDC buses would cause Neutron Monitor Lo.w Sup-ply alarm to come* up. The unit battery charger room has the following indications:. charger. voltage a~d amps, Bus A and B
- p~s~_t_~~~*-~~~~:~~~~~~~i.~--~-~~-~a~~~:.~t~:;.?~~~~i~~~~I;::{~-:~- "~" o**-:~..
B. Th~ *fo1i~~1;-g*:1oa<ls -are.c~nnected_t:C:> the._24/.48.vnc.:system~:: _____...::.:;.:.,_*_ ~- Panel 902(3). Process Radiation Monitor Panel 902(3)-36:.. -: Source and Intermediate Range Monitor ~(SRM and'..
- IRM)
Panel 923 Process Radiation Monitor (Units 2 and 3) Loss of the entire 24/48 VDC system will disable the process liquid radiation monitors and the chimney effluent monitors. The trip logic for the SJAE off-gas radiation monitors comes from the 24/48 VDC bus, the high radiation isolation would not ftmction. The -SRM and IRM's will not function when the bus is lost. Oper-ating-in any mode but RUN, the IRM protective relays will de-energize and a reactor scram will occur. The SRM and IRM indica~ tions, recorders, and lights will also he lost. Due to the use of both the battery chargers, the battery".itself, *and the redun-dant A and B buses, it is not anticipated.that *a-loss of the en-tire system is likely. If a loss-of the entire system did occur,
- the reactor can still be brought to, and maintain, a cold shut-down condition, due to the. availability of feedwater, ECCS, reactor normal control, shutdown cooling, and the main condenser.
- c. *No modlfic~tions. are pr_oposed. based-on the:* abo.ve::_ieview. ~-*
~ ~....... ... -~..
~- -
Both 120VAC. RPS-.huscs*-=-are*supplied normully:~*hy:.*~~-f:i~G set. which is-:-'.~-:.:.... fed from 480 VAC MCC 28()8)-'2 :ind 29(19).:_2.- TI11.iHe MCC's ure irnpplit!d
- .....: ~ '*
. ~.~
- 1.
(Continued) from emergency. 480 VAC buses 28(38) and 29(39), which can be fed from their own emergency diesel generator.. _ A r~s.erve_~upply ___ i~ __ key _.... __,... -*-** interlocked with 480 VAC MCC., 25 9_5.J~-~~-~~,~~-~~~e~e~n(*§~rnui t.a.neous:. fe_e.d, ~'.::c~,;:*';~;t~"~"--4:;'7; to the RPS buses. A. Loss of both RPS buses for the unit will result in a. reactor. - scram. Group II and III Primary Containment Isolation (PCI) will occur, as will half the permissive for a Group I PCI. Numerous control r~om alarms, as well as the reactor and turbine-generator parameter changes associated with a reactor scram will alert the operator to a loss of power to the RPS buses. There are indications for bus amps; bus voltage, and generator voltage in the auxiliary electrical equipment room. B. 111.e following loads are connected to the RPS buses: Bus 2(3)A
- 1.
- 2.
- 3.
Bus 2(3)B I.
- 2.
- 3.
Panel 902 (3)-:-10,. - Process Radiation Monitoring Panel 902(3)-15 _-: RPS. and PCI.. relays.. :. Panel 902(3)'-37 Power Range Neutron Monitoring Panel 902(3) Process Radiation Monitoring Panel 902 (3)-17 RPS an.d PCI relays Panel 902(3) Power Range Neutron Monitoring.. '- - -~--=-- ..:..-:.=..-:._::_~~*-. *----=---- - -*-= ---------. --. ~ .. --:,, ______....... - ---'-==.-... -*-... :.......=... ::~:;--::::-:--.::.==-_-:*~~-=-=.::~-<=:=':..o=~:-'--*=.*::~_:.:.;_:_ ~~.: -~--:::.~.::.;~=~ The loss of both RPS _buses _will r_esult _in a reactor scram and -a.:*~.
- -*"~-~-.2:.::,
-.*:*-*-*---,.:*7-.,,----... -.-.. -....:""*"" "-'-t Group II* and III-isolation*:-: From. thi~..__logie:,:::.th.~.-:-?E!_C:~~.1:1]<:_a~-:::-:;-~~-- ~ *::_::::.c*:*:_c_:~~ vacuum pump trips_ and SJAE. suction valve will close. A Group I isolation will not occur, since the es*sential service bus supplies power to channel B isolation relays. In hot shutdown, the follow-ing conditions* exist: normal feedwater, condensate-, and level. ".-.. control are operable, and the main condenser is available to be used as a primary heat sink, the reactor can reach and maintain cold shutdown conditions. Loss of RPS~ power to the 902(3)-10 panel would isolate the Reactor Buildlhg Ventilation anri Fuel Pool monitors. Loss of power to the Offgas SJAE Radiation moni-tors will start the 15-minute isolatio'n timer. The timer can be reset to prevent an off-gas isolation so the main condenser can remain available. Loss of power to the 902(3)-37 panel will re-sult *in a loss of Power Range Neutron monitoring, but with the reactor shutdown, it is not needed.. It will also cause a loss of Recirculation Loop Flow instrumentation; however, pump speed, jet pump flow, and _total core flow instrumentation will still be operable and Recirc. Pumps will be running at minimum speed. All ECCS system will remain operable with a loss of RPS power. C. No modifications are proposed based on the above revie~. . --~***,..._..., .,_.-,=;:
- ---;::-.;.:...;~-.:*.~:.-*.,
The 120/240 VAC.ESS is normally:* energized. from'.:a~ *Ji-G ~et which *is fed* =.<.:::.~.~-..,i _.. *f~om 480.VAC Bus 29(39). -:r(tli~:.-no~mal.. AC._p~,;~r s*h~uid fail;* the-~-.-~-*-~;:~,::~,~~..;;~ -. -turfiine b~ildfrig 250 vDC MCC 2 (3) will provide. power. to the_ M-:-G set.. -.- "'::::,.;... -;-~ - '..( motor._* There is *a power seeking automatic transfer switch to MCC -:,.. -_ * :-.. ;-..:: _-;~::;:1 ---~- *
- 2st3s).:::2 :-if°-'b"6-th::-.:.;i~ -th'~~ '.6.c-=--i~*;r nc 'po~ei--:,.:5-o-~t-ces-"are--:10*sr-=.""=~-*~-.~~~ :--':"~-~-.. -~~,-,=--~~~~-~~- ~~~
---.-: :=:.....=:::.-._- ----~:.: *::-. ~- - - --,I _:~*=-.~. .~-':':*-.:_ ':_--:_--.=:::.:~-~'=:;:.':":~-* ---~----:-""... ---*. -:c- ___,"_':_-~c-:3
- 1.
- -~-.
~-. (Continued)_ A:.* Control Room alarms are:*... :
- 1)
ESS M-G Set AC_. Feed Trip
- 2)
ESS M-G Set DC Feed Trip
- 3) 120/240 VAC ESS Service Bus on Emergency Supply
- 4) 120/240 VAC ESS Service Bus Voltage Low Indications located in the auxiliary electrical equipment room are:
AC motor amps and voltage, DC motor amps and voltage, AC. generator amps and voltage, bus amps, vo~tage, and frequency. Tiie B and D ~~in Steam Line Radiation Monitors are powereo by the ESS Bus. Alarms that will come up are: Channel B reactor scram, channel .B main steam high radiation, and Group I isola-tion Channel B trip, if ESS is lost. Alarms for loss of power* to the process. computer ~re: recirc. flow limit, RPIS inopera-tive, and low vessel water level. Tiie following loads are connected.to the ESS Bus: Panel.?252 (3)-7
- ~ner_at~r* H~d.rogen._ and. __ -~t~to~,~co~lln~* ~-;;~:~~'~:_-_:-,'~:{:-:-.-~:- :.~-~
Panel 902(3) Stack gas, off-gas Panel 902(3)-33.,.:-:...~ore. Spray and LPCI System II Panel 902(3) Reactor Hanual Control Panel 902(3) Core Spray st..mlp ptnnp Panel 902(3) Recirc. Pump speed control, Channel B sensor relays and trip relays Panel 902(3) Off-gas valves, control panel Panel 902(3) HPCI instrument power supply Panel 902(3) SRM, IRlt, APRM, RBM recorders and feedwater control Panel 902(3)~45 - Rod Worth Minimizer Computer Computer Main Feed Cabinet - Comptlcter _ P~-~~~~~ral.and Transducer Power _*Supply_ Cabinet . _). ~-:-*- ---- ~{
- ~
B and b Main Steam Line Radiation. monftors-- ----* *c*.- - ------*._:_**--,4 -'---~-*----.::::::-.~-:_. :_ __ --* -- -- "Pane ls 902(3)-3, 4:*.?~_-and 6 -=.-*contiolRoom* panels*** . "-~1
- .. -.:-:~t
-\\ . -. -*-J --*--1 ="='
.,. 1. B. (Continued) Panel 90?(3)-10 Process Radiation* Monitor---,.***.:.,~,_:;.. . - ~-.. - *- -:-. *-.
- . -* ;-.* -. - *-:"":, -"..;..- ::..;.. -=
-~-:-.~ --. *--:.-.:..-~--. *: ;*-.=..: __ i:J.,,,_r~:-~~:.;.~.-:;--- :-.* -. Panel 902(3)-17 PCI Channel B isolation relays Panel 902(3) RPIS relays Loss of ESS could eventually cause the reactor to be shutdown. 'Illis would be due to a loss of vacuum resulting from the off-gas. isolation and SJAE suction valve closure. In hot shutdown, the followir.tg conditions exist: narrow range GEMAC water level in-dication, reactor pressure, s~eam flow, and feed flow will still be available. There would be a loss of the feedwater level con-trol system, HPCI flow control, isolation condenser flow control, the feedwater pump minimum flow valves will fail open, narrow range GEMAC recorder, narrow and wide range Yarway level indica-tion, and recirc. pump speed control and indication. A Group I PCiwould not take place due to the RPS Bus supplying power to Channel A isolation relays. The chimney activity re-corder _would be lost; however, the chimney and SJAE monitors would still be available. Shutdown cooling, ADS, and all low .. * :: __ ~~.;~::~:~:~]~~:;~S~~;~~:!:!f 4f~I~2{It:~A~t;So~~}~{f;~~~~~"2~~~~ . does not appear to be a problem, based on the inventory of. water - -available, shutdown cooling, ADS,low pressure ECCS, and rod block and CRD scram functipns would be operational.-- Other ~oads that would he lost are of ~o significance in placing anc main-* taining the reactor in cold shutdown. C. No additional modifications are proposed based on th*e above review.*
- 2.
The existing emergency operating procedures have been reviewed. ni.ese procedures include symptoms, action to be taken, and alarms, which. are sufficient to restore power to the bus. Based on this re-view, no revisions are proposed.
- 3.
I.E. Circular No. 79-02 has been reviewed. The difficultie~ de-scrioed by the circular were caused by a failure of solid state un-interruptible power supplies. The specific trouble was with _the in-verters and static switches; A review of the items of concern-* listed oy the circuiar as compared to equipment at Dresden Units 2 and 3 was made.. : .. ~ Since -there is.no equipment of the nature described.by.the circular,
- ~-,x
.. :_:... '."no action on any**of"'the items.to be considered. is required at the:*.
- *
- pr~s~nt time~ However; modifications are in -progref:is.(;o.replace'*~-:"-.::-:>***::*~,,~.:*._.. ~~:--~::?,
--tfte ESS M"'-G S~t~ With static inverters. A copy of the *C:t.rcular was.. :
- '~'
sent to C~~~nw~~lth Edison Company Station Nuclear E~*gin~~ring De--* -:-*- --:-*:**: partmeri~ (SNED) ~-: - Those review items a!ld recommendations gi_-'.'.'.en i!l _.,.,_ *.*... ( ___ *:': *c:*-:.:~
the--drcufar-.will.. be.r*e-.::examfoed. and-liiiplenieiited-*as**necessary by-:::-::*:_*:-:-=.::~--:-::--:-::-:-'
... *-- ~~~D _ pr~or~
- c:a __,.._c. om_-P_)~ tin~. the.modific*a don_9-T:_::_~_,_*:..:.- '-~~~~~: ~.:_.,_:~:~.i~~~~~:.:** c'..:.-:~-:.-.*~_;~-:-~:=.:~_-:_::~ -* -~
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