ML20035H339

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Summary of 930205 Meeting W/Bwrog Re Atws/Stability EPGs
ML20035H339
Person / Time
Issue date: 04/27/1993
From: Phillips L
Office of Nuclear Reactor Regulation
To: Rosalyn Jones
Office of Nuclear Reactor Regulation
References
NUDOCS 9305040252
Download: ML20035H339 (36)
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Text

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E WASHINGTON D. C. 20555 E+% l s April 27, 19893 %,*.U...# MEMORANDUM FOR: Robert C. Jones, Chief Reactor Systems Branch Division of Systems Technology FROM: Laurence E. Phillips, Section Chief Core Performance Section Reactor Systems Branch Division of Systems Technology

SUBJECT:

MINUTES OF MEETING WITH BWROG ON ATWS/ STABILITY EPGs The NRC and BWROG met on February 5, 1993 to discuss the status of EPG revisions for mitigation of ATSW/ Stability concerns. The primary subject areas were the time of initiation of boron injection (via SLCS), RPV water level reduction (when and how far) and interlock bypass (to stop MSIV closure with lowered level in order to maintain a heat dump other than the suppression pool). The proposed SLCS initiation is when oscillations exceed 25% peak-to-peak. Interlock by pass is proposed to be as soon as possible after initiating level reduction. Level reduction begins when ATWS is confirmed (ARI does not insert rods). Level is to be controlled below the feedwater sparger by terminating all injection into the RPV except boron injection and CRD. Water level may be lowered to (nominally) the top of the active fuel (TAF) with a level control band extending _down to the minimum steam cooling RPV water level (MSCRWL). The primary concern of the staff was the EPG permission to lower the level significantly below the feedwater sparger (where large-oscillations are effectively suppressed) down to as low as the MSCRWL in order to lower power and provide minimum containment heatup. Analyses by T. Theofanous, which have been seen by the staff, have indicated that there may be boron mixing problems associated with the lower levels which negate any claimed improvement in integrated power and containment heatup. It was concluded that another meeting should be arranged in the near future, with T. Theofanous participating, in order that BWROG can better understand and address the Theofanous concerns. 9305040252 930427 ]fj PDR ORG NRRB PDR [ g a

m 6 . l L An attendance list and copies of slides from the meeting are in the f enclosure. ~ 77 d '(, Q ,1 ff Laurence E. Phillips, Section Chief Core Performance Section Reactor Systems Branch Division of Systems Technology

Enclosure:

As stated cc: W. Russell A. Thadani P. Boehnert H. Richings 'PDR

Contact:

H. Richings, SRXB/ DST /504-2888 t a b P i r i

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4 ' NRC/BWROG/GE MEETING TO DISCUSS STATUS OF 1 EPG REVISION FOR ATWS/ STABILITY i I FEBRUARY 5, 1993 HCP8/020593 j

i l MEETING PURPOSE DESCRIBE PLANNED EPG REVISIONS WHICH ADDRESS STABILITY o o OBTAIN NRC COMMENTS / FEEDBACK I o AGREE ON ATWS/ STABILITY CLOSURE PLANS I k k d l HCP8/020593

AGENDA F 8:30 INTRODUCTION / STABILITY OVERVIEW T. RAUSCH 1 I 9:00 EPC PRESENTATION W. WILLIAMSON T. ROGERS ALL 10:00 DISCUSSION / AGREEMENTS-',;,;ts *Ai. 11:00 ADJOURN 6 HCP8/020593

i h ATWS/ STABILITY OVERVIEW BWROG IS COMMITTED TO RESOLVING ATWS/ STABILITY ISSUE o BWROG ATWS/ STABILITY CLOSURE PLAN DISCUSSED WITH o NRC (8/91) PART 1 - ADDRESS ATWS RULE ISSUES l PART 2 - IMPLEMENT APPROPRIATE ACTIONS (INDEPENDENT OF ATWS RULE) PART 1 ADEQUACY OF ANALYSIS / ANALYTICAL TOOLS ASSESSED o INDEPENDENT INDUSTRY TASK FORCE AND PEER REVIEW NRC/0RNL/BNL/INEL AUDIT OF TRACG AND ITS APPLICATION t ATWS/ STABILITY ANALYSIS PERFORMED AND RULE ISSUES o ADDRESSED IN NEDO 32047 (2/92) CANNOT PRECLUDE POSSIBILITY OF LIMITED DAMAGE LEVEL OF SAFETY EXPECTED FROM 10CFR50.62 IS NOT COMPROMISED BECAUSE OF STABILITY I i HCP8/020593 1

ATWS/ STABILITY OVERVIEW PART 2 ATWS/ STABILITY MITIGATION ANALYSIS SUPPORTING EPG o HODIFICATIONS REPORTED IN NEDO 32164 (12/92) FEEDWATER RUNBACK QUICKLY REDUCES OSCILLATION AMPLITUDE WITH LEVEL BELOW FW SPARGER RESTARTING FW DOES NOT RESULT IN LARGE OSCILLATIONS BORON WILL TERMINATE OSCILLATIONS BUT IS SLOW l ACTING L o FINAL EPG MODIFICATIONS MUST BALANCE ATWS/ STABILITY ACTIONS AGAINST ENTIRE SPECTRUM 0F EPG ACTIONS TO ENSURE A POSITIVE OVERALL RESULT COMMITTEE HAS DEVELOPED APPROPRIATE GUIDANCE ALL ATWS RULE ISSUES HAVE BEEN ADDRESSED i HCP8/020593

f ATWS/ STABILITY ISSUE i THE BWROG BELIEVES THAT WITH EPG MODIFICATIONS o ALL NRC ISSUES WILL HAVE BEEN ADDRESSED e THE REMAINDER OF THIS MEETING WILL FOCUS ON THE PLANNED o EPG 110DIFICATIONS AND THEIR BASES l. 4 i l i HCP8/020593

i i EPG Changes to Address Potential Reactor Instabilities l Introduction t Bases for EPG Development and Revision Phenomena Underlying Planned EPG Changes i Planned EPG Changes j RPV Water Level Reduction Interlock Bypass Boron Injection Expected Plant Response Il BWROGiu'RCmeedog BTW-1 February 5,1993

l t Introduction I i EPG Stability Modification History l t 1 EPC-II tasked with drafting changes in parallel with j analysis 1/92 EPC meetings (supported by Stability Committee) i Subcommittee meetings 2/92 and 5/92 1 Full committee meetings 4/92 and 6/92 EPC approved stability modifications based on 1 assumptions involving phenomena 6/92 l ATWS mitigation studies completed 11/92 Last results presented to EPC 1/93 Results support bases for EPG modifications I 1 BWROGNRC meeting BTW2 February 5,1993

l I Introduction (continued) BWROG/NRC Meeting i t Our purpose Present modifications to EPGs Present technical basis for EPG modifications f Receive NRC feedback ) + i 6 l I i BWROGNRC meeting BDY3 February S,1993 i P

t I i i Introduction (Continued) Remaining Actions forImplementation f 1 1 i GE design review i Appendix B changes i t On receipt of written NRC approval, submit to l utilities for implementation i l i j [ i p a i t e

i BWROGNRC meeting BTW-4 February 5,1993

l l Bases for EPG Development and Revision i EPGs specify an integrated set of operator actions to l address a very broad spectrum of events I l At any point in any event, further system and l equipment degradation is always possible; EPGs i specify actions to return the plant to a safe, stable condition without depending on any one system or piece of equipment t EPGs specify the best possible generic guidance; meeting regulatory requirements (e.g.,10 CFR 100 limits) is not, by itself, sufficient j EPGs balance the probabilities and consequences of l all possible outcomes so as to minimize the risk to the health and safety of the public l BWROGNRC meeting February 5,1993 STR-1 i t

Bases (continued) From EPG Appendix B, Section 2: "3. The operator actions specified are consistent with the manner in which control room operators actually operate plants, including concurrent or parallel performance of actions." "5. With the exception of hydrogen generation in a BWR/6 Mark III plant, all mechanistically possible plant conditions for which generic operational guidance can be provided are addressed, irrespective of the probability of occurrence... "9. The best possible operational guidance is specified, irrespective of licensing or design-basis assumptions or commitments..." BWROG NRC meeting STR-2 February S.1993

i Phenomena underlying j Planned EPG Changes r Reducing the core inlet subcooling will reduce the likelihood, magnitude, and duration of large l irregular oscillations Reducing RPV pressure may increase the potential for large irregular oscillations i Increasing the concentration of soluble boron in-the reactor coolant will ultimately terminate all oscillations j Injecting soluble boron into the reactor coolant will l not appreciably reduce the magnitude of large irregular oscillations in the short term j i If oscillations sufficient to damage fuel can occur, they will occur soon after core inlet subcoohng is i increased If fuel damage occurs,it will not propagate between fuel bundles l BWROGNRC meeting STR-3 February 5,1993

Phenomena (continued) More reactivity will be added by, and thus a larger reactivity excursion can result from, the displacement of warm borated coolant by cold unborated coolant than the displacement of warm unborated coolant by cold unborated coolant The core will not be damaged (beyond fuel pin perforations) by other than large irregular oscillations so long as RPV water level is maintained above the Minimum Steam Cooling RPV Water Level i i STR4 bru 5,1993

- =. i 1 i i Planned Changes RPV Water Level Reduction 1 i i Control RPV water level below the feedwater sparger j to minimize core inlet subcooling i C5-4 If RPV water level is above Ixxx in. fvv inches below the feedwater snarcer no721es11 and the reactor is not shutdown: ~ l = If any MSL is not isolated. bynacs low RPV water level interlocks j to maintain the main condenser as a heat sink and Imver RPV water level to below fxxx in. (vv inches below the e feedwater scarcer no721es11 by terminating and nreventing all iniection into the RPV excent from boron infection =vstems and CRD. defeattnc interlocks as necessarv. l l i Control RPV water level above the Minimum Steam i 3 4 Cooling RPV Water Level to provide a more l practicable water level control band l t l ti C5-5 Maintain RPV water level between 1-195 in. (Minimum Steam [colina RPV WaterIrveU1 and either: 0 If RPV water level was deliberately lowered in [ Step C5-3 or C5-41, between44954n,4MuumumSteamCooung I Rm7 Water-JaccU] and the level to which it was lowered. or If RPV water level was not dehberately lowmd in IStep C5-3 DI ] C5-41, between 44Gian,4topofa:tivefueUIand 1458 in. (high ) level trip setpoint)l. 1 BWROGNRC meeting STRS February 5,1993 l ..\\

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. ~.. _ _........, _.. _ _ _. _, _ - _....., _. _. _ -

? i b Planned Changes j Interlock Bypass i F t Bypass low RPV water level interlocks as soon as practicable to maintain the main condenser as a heat sink during water level reduction j i t If any MSL is not isolated. bvoass low RPV water level Interlocks to f e C5-2 maintain the main condenser as a heat sink. C5-3 If:

  • Reactor power...

'Ihen: i _* If any MSN MSL is open not isolated. bypass low RPV water level pneumatic cystem rd MSFJ ischtdon interlocks and [ restore 4he-pneumatWply !!c the containmenti to maintain j the main condenser as a heat sink and

  • Lower RPV water level, irrespective of any ocnsequent reactor i

power or RPV water level oscillations, by terminating and preventing allinjection into the RPV except from boron injectJon systems and CRD. defeattna interlocks as necessary. until either-f .j ~! BWROGNRC meeting i STR-7 Februsty 5,1993 e

3 r f t a Planned Changes Boron Injection 1 ? b Require boron injection if oscillations exceed 25% peak-to-peak j i RC/Q-6 Either- = When oeriodic neutron flux oscillations in excess of f25% (Laroe Oscf!1ation Threshold 11 neak-to-neak commence and continue. or i Before suppression pool temperature reaches [the - Boron Injection Initiation Temperature] but-only44he [ reac4cr-cannet be chuth I BORON INJECHON IS REQUIRED: inject boron into the

j RPV with SLC and prevent automatic initiation of ADS.

Boron Injection Initiation Temperature t m.: l w .dL7:, i l 22 fo s n g 4 M4 Y (' .. c.. 3 V.; i N a 1CO j 0 1 2 3 4 8 Reactor Power (%) BWROGNRC meeting STR4 February S.1993 -

i Boron Injection (continued) l r Both EPG Rev. 4 and the planned changes permit a boron injection any time after ARI has failed to i function Boron injection as required by EPG Rev. 4 may not occur until after oscillations are observed r Planned changes require boron injection if oscillations are observed j Boron injection before oscillations are observed may unnecessarily increase the adverse consequences the of some events, for example: Partial rod insertion with loss of high-pressure injection i Partial rod insertion with loss of RPV water level indication i Boron washout at low pressure i BWROGNRC meeting STR 9 Febtvary 5,1993

Expected Plant Response i Reducing RPV water level to below the feedwater sparger will prevent or terminate fuel-damaging oscillations Bypassing interlocks promptly will reduce the containment challenge from ATWS, whether or not oscillations occur Requiring boron injection when oscillations are observed will terminate oscillations sooner for those cases in which the operator would have chosen to delay boron injection under EPG Rev. 4 l I BWROGNRC trusting STR 10 February 5,1993

CONCLUSIONS EARLY ACTION TO BEGIN LOWERING WATER LEVEL (TERMINATE o FEEDWATER) IS BEST ACTION FOR DEALING WITH POTENTIAL FOR LARGE OSCILLATIONS ONCE LEVEL IS BELOW FW SPARGER STABILITY CONCERNS ARE o ADDRESSED FURTHER LEVEL REDUCTION ISSUES ARE NOT STABILITY o RELATED AND SHOULD BE SEPARATED FROM THE ATWS/ STABILITY ISSUE BORON INJECTION IS EFFECTIVE BUT SLOW WORKING.. THE o PLANNED EPG MODIFICATIONS ENSURE THAT BORON INJECTION IS TIMELY AS A SECOND LINE OF DEFENSE i I HCP8/020593 i

f h 1 i I l EPG Changes 1 [Or i ? i Potentia 1 Reactorlnstabilities j l I i l f k l I f I t

4 ~ OEI Document 8390-4 BC/Q Monitor and control reactor power, t If while executtng the fo!!owing steps:

  • All control rods are insened to or beyond position (02 (Maxtrnurn Subcrttical Banked Withdrawal Position)\\

terTninate boron injectjon and enter [ scram procedurel.

  • 11 has been determined that the reactor will remain shutdown under all conditions without boron.

terminate boron injection and enter [ scram procedurel.

  • The reactor is shutdown and no boron has been injected into the RPV enter [ scram procedurel.

RC/Q-1 [ Confirm or place the reactor mode switch in SHUTDOWN.] If ARI has not initiated. Initiate ARI. _ RC/Q-2 ~ If the main turbine-generator is on-line (and the-MSIVs RC/Q-3 are-open an MSL is not isolated.1 for if any of the followinc systems are cocrating: Feedwater HPCI RCIC 1 confinn or initiate recirculation flow runback to i minimum. ~ RC/Q-1 If reactor power is above 13% (AFRM downscale trip)] or cannot be determined, trip the recirculation pumps. If ARI has not initiated. initiate ARI. - RC/Q-5 Execute [ Steps RC/Q-6 and RC/Q-71 concurrently. 1 l i EPC Openitern 8953 S. T. Rogers RC-11 Draft S6

OEt oocument 8390-4 1 i RC/Q4 Either;

  • When neriodic neutron flux ovillations in excess of 125% (Larce OscJfarfon 75 reshofrD1 neak-to-oeak t

commence and continue. or

  • Before suppression pool temperature reaches (the Boron Injection Initiation Temperature] but ^aly Lr the reacter craet ha shut dem i

BORON INJECTION IS REQUIRED; inject boron into the i RPV with SLC and prevent automatic initiation of ADS. Boron Injection Initiatlon Temperature la0 m e 5 li 12 k! g ,I '" - V g g g 110 b a 100 0 1 2 3 4 5 6 t i Reacw Power (%) i If boron cannot be injected with SLC. inject boron into the RPV by one or more of the following alternate methods:

  • CRD
  • HPCS
  • RWCU
  • Feedwater
  • HPCI h
  • RCIC i

Hydro pump EPC Openitem 8953 Draft SG s RC-12 S. T. Rogers L

OEl Document 8390-4 If while executing the following steps SLC tank water level drops to [0% (Iow Sir tank water level trip)]. confinn automaue trip of or manually trip the Sir pumps. RC/Q-6.1 If boron is not being injected into the RPV by RWCU and RWCU is not isolated, bypass [regenerauve heat exchangers and] filter /demineralizers. RC/Q-6.2 Continue to inject boron unul 1700 pounds (Cold Shutdown Boron Weighdl of boron have been injected into the RPV. RC/Q4.3 Enter iscram procedurel. RC/Q-7 Insert control rods as follows: RC/Q-7.1 Reset ARI-defeating-ARI logic trips if necessary. RC/Q-7.2 Insert control ruds with one or more of the following methods:

  • De-energize scram solenoids
  • Vent the scram air header

. Reset the scram defeating RPS logic trips if necessary, drain the scram discharge volume, and initiate a manual scram

  • Open individual scram test switches
  • Increase CRD cooling water differential pressure

. Drive control rods, defeating RSC5 and RWM Interlocks if necessary

  • Vent control rod drive overpiston volumes EPC OpenItem 8953 Draft SG RC-13 S. T. Rogers

l oei oocument 8390-4 CONTINGENCY #5 l LEVEIJPOWER CONTROL If while executing the following steps:

  • RPV water level cannot be determined, enter (procedure I

developed from Contingency #4).

  • All control rods are inserted to or beyond position 102 (Maximum Subu '.tical Banked Withdrawal Position)) or it has been l

deteTained that the reactor will remain shutdown under all cond tions without boron enter (procedure developed from the RPV :ontrol Guidelinel at (Step RC/LI.

  • Primsty containment water level and suppression chamber i

pressurt cannot be maintained below the Maximum Primary Containment Water Level Limit, then irrespective of whether f adequate core cooling is assmed terminate injections into the RPV from sources external to the primary containment until l primary containment water level and suppression chamber pressure can be maintained below the Maxirnum Primary l 3 Containment Water level Limit. Marimum Primary Cont =Inment Water Level Limit l 120 - '} e 5a

I

~ j 100 I" ,h.[L gn T e l m-g 5 50 h 1 p 8 1< ,L( / ? 4 O 5 ** % p;c .g g ^ t 'o 0 10 20 30 40 50 e0 70 j Suppression Chamber Pressure (psig) - l l EPC Openitem 8953 DrnftS6 C5-1 S. T. Rogers 'f

OEIDocument 83904 C5-1 Prevent automatic initiation of ADS. ~ If any MSL is not isolated. bynass low RPV water level interlocks to C5-2 maintain the main condenser as a heat sink. C5-3 If:

  • Reactor power is above 13% (APRM downscnfe trip)) or cannot be determined, and
  • Suppression pool temperature is above (the Boron Injection Initiation Temperaturel, and Boron injection Initiation Temperature 14o -

^ LA. s3 133 1 2120 -N 1-y 110 E a im 0 1 2 3 4 5 4 Reactor Power (%)

  • Either an SRV is open or opens or drywell pressure is above (2.0 pstg (high drywell pressure scram setpoindl.

EPC Openitem 8953 Draft S6 CS-2 S. T. Rogers

OEI Document 8390-4 Then: _

  • If any MSiv MSL is open not isolated. bypass low RPV water level pneum'Uc syraun 2nd MS"' 's@tinn interlocks and restotuhafnemmuc-supply-{lo4h+wmninmenti to maintain the main condenser as a heat sfnk and
  • Imer RPV water level. Irrespective of any consequent reactor l

power or RPV water level oscillations. by tenninating and preventing all injection into the RPV except from boron injection l systems and CRD. defent!nc interlocks as necessary. until either: Reactor power drops below [3% (APRM downscale Inp)), or RPV water level reaches {-164 in. (top of actitefuel)). or + All SRVs remain closed and drywell pressure remains below (2.0 psig (high dnjwell pressure scram setpoUull. If while executing the following steps Emergency RPV DepressurizatJon is required. continue in this procedure at [ Step C5-5.ll. If RPV water level is above fxxx in. (vv inches below the feedwater C 5-4 scarcer nor21esll and the tractor is not shutdown: _* If any MSL is not isolated. bynass low RPV water level interlocks to maintain the main condenser as a heat sink and _ = Lower RPV water level to below lxxx in. Ivy inches below the feedwater scarcer nozzlesil by terminatinc and nreventinc all injection into the RPV excent from boron iniection systems and CRD. defeatina interlocks as necessary. EPC Openitem8953 Draft S6 CS-3 S. T. Rogers

..a a, ,. - -. ~ - ..s.. .7 i A-f i + OEIDocument 83904 i i P if while executing the following step: I E

  • Reactor power is above (3% (APRM downscale tripll or cannot be j

determined, and r

  • RPV water level is above [-164 in. (top of actitefueUI and i
  • Suppression pool temperature is above (the Boron injection Initiation Temperaturel, and
  • Either an SRV is open or opens or drywell pressure is above 12.0 psig thigh dnjwell pressure scram setpoindl.

l return to (Step C5-31 C5-5 Maintain RPV water level between f-195 in. (Mfntmum Steam@ Coolino RPV Water LeteUI and eithen f

  • If RPV water level was delfverately lowered in IStep C5-3 or C5-41, be+"ceen H951%!Mta3"r S9ea CMMg

. l I W/ "'er L~c"] 2nd the level to which it was lowered. or i l

  • If RPV water level was not deliberately lowered in [ Step C5-3 or 1

fd-il, bet"ceen H64 M fbp of ~"~f "! rd [+58 in. (high level trip setpoint)). with the following systems:

  • Condensate /feedwater
  • CRD
  • RCIC with suction from the condensate storage tank.

gg l defeating low RPV pressure isoladon interlocks and high suppression pool water level suction transfer logic if necessary. _

  • HPCI with suction from the condensate storage tank, defeating high suppression pool water level suction transfer logic if necessary.

I i i ~ EPC Openitem 8953 DrapS6 CS-4 S. T. Rogers .J

e ~ OEI Document 6390-4

  • LPCI with injection through the heat exchangers as soon as possible; control and maintain pump flow less than the RHR Pump NPSH Limit and [the RHR Vortex Limit].

RER Pump NPSH f.f mit 250 - u.~ N 240 -m 5 q<= -o..a I 1m I' E N g - S we, j a c 210 N i !~ i

y. - >

0 23]O 432 6003 a000 10000 120C0 190 RHR Pump Flow (gpm) i I RHR _ Vortex Limit 50-E }3 1 3 i E3 i a. h g I 0 2000 4000 ex10 a000 10t00 12000 40 RHR Pump Fbw (gpm) If NJ u ate Jere!"s nh.11bente!y !mvced4n4 Step C521-and Rm! water-le. vel 4annot-be-maintainedabove4464-4n,4 top 4facthe amintainsm! m2 term 4 ween 44454n4Minimumsteam fue#fr Wghle-vel L? Se!pOU%ll. Coully Rm! n%tsrda" L1 a"d [+5" L" If any MSL is not isolated bvoass low RPV water level interlocks to maintain the main condenser as a heat sink. r l Draft S6 EPC Openitem 8953 C5-5 S. T. Rogers

O t OEI Docurnent 8390-4 ~ If RPV water level cannot be maintained above [-195 in. (Minimum Steam Cooling RPV Water LeveOl. EMERGENCY RPV DEPRESSURIZA'IlON IS REQUIRED: Terminate and prevent all injecuon into the RPV except C5-5.1 from baron injection systems. CRD. and RCIC. defeaunc interlocks as necessarv. until RPV pressure is below the Minimum Altemate 3PV Flooding Pressure. Number Of RPV Pressure Open SRVs (psig) 7 or more 94 Minimum 6 112 Alternate RPV Flooding 5 137 Pressure 4 175 3 238 2 364 1 743 If less than (1 (minimurn number of SRVsfor which the Minimum Alternate RPV ETooding Pressure is below the lowest SRV l(ting pressurell SRVls) can be opened, continue in this procedure. C5-5.2 Commence and,irrespecuve of pump NPSH and vortex 6 limits. slowly increase injection into the RPV with the following systems to restore and maintain RPV water level above N64-indt@cuve4sely f-195 in (Minimum Steam Cmlina RPV Water IrveUl:

  • Condensate /feedwater
  • CRD
  • RCIC with suction from the condensate storage tank, defeating low RPV pressure isolation interlocks and high suppression pool water level suction transfer logic if necessary.

_

  • HPCI with suction from the condensate storage tank, defeating high suppression pool water level sucuan transfer logic if necessary.]

~ EPC Open item 8953 Dmft S6 C5-6 S. T. Rogers

O i s OE! Document 8390-4 ~ -

  • LPCI with injection through the heat exchangers as soon as possible.)

If P"'" 2ter hvelcarnhestoredandandntained above !-161 !". (!cp ofecthef=U!, rectore and mamt21a. PPJ ' vater level 2beve l-195 in.-P.4inenwn, Steam CMhg P"'Vder Lew20h t If RPV water level cannot be restored and maintained above \\ 195 in. (Minimum Steam Cooling RPV Water LeteU), conunence and, irrespective of pump NPSH and vortex limits, slowly increase injection into the RPV with the following systems to restore and maintain RPV water level above \\-195 in. (Minimum Steam Cooling RPV Water Extcul:

  • HPCS
  • LPCS j

_

  • RHR service water crosstle
  • Fire System
  • Interconnections with other units
  • ECCS keep-full systems If RPV water level cannot be restored and maintained above 1-195 tn. (Minimum Steam Cooling RPV Water j

leteU), enter (procedure developed from Contingency #61 i C5-5.3 When RPV water level can be maintained above [-195 in. (Minimum Steam Cooling RPV Water IzteUI, return to IStep C5-5). l EPC Openitem 8953 Draft S6 C5-7 S. T. Rogers

a OEI Document 8390-4 If while executing the following step reactor power commences and continues to increase. return to (Step C5 31. When 1364 pounds (Hot Shutdown Boron Wetghtll of boron have been C5-6 injected, restore and maintain RPV water level between (+12 in. (Iow level scmm setpoint)l and (+58 in. (high level trip setpoint)l. If RPV water level cannot be restored and maintained above (+ 12 in. llow level scmm serpoint)l. maintain RPV water level above I-164 in. (top of activefucUl. If RPV water level cannot be maintained above 1-164 in. (top of active fueUl. EMERGENCY RPV DEPRESSURIZATION IS REQUIRED: return to [ Step C5-5.11 When [ procedure for cooldown to cold shutdown conditions) is C5-7 entered from (procedure developed from the RPV Control Guidelinel at [ Step RC/P-51 proceed to cold shutdown in accordance with Iprocedure for cooldown to cold shutdown conditionsl. EPC Openitem 8953 Dmft SG C5-8 S. T. Rogers}}

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