ML20137L065
| ML20137L065 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 11/30/1994 |
| From: | FLORIDA POWER & LIGHT CO. |
| To: | |
| Shared Package | |
| ML20137K821 | List:
|
| References | |
| FOIA-96-485 JPN-PSL-SENP-94, JPN-PSL-SENP-94-079, JPN-PSL-SENP-94-79, NUDOCS 9704070148 | |
| Download: ML20137L065 (15) | |
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i ENGINEERING EVALUATION l
4 ASSESSMENT OF ECCS SUCTIOIf PIPING CROSSTIE DUE TO DESIGN OF NaOH SPRAY ADDITIVE SYSTEM i
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ST LUCIE NUCLEAR PLA!'T i
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UNIT 1 l
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JPN-PSL-SENP-94-073 i
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REVISION O 1
SAFETY arf 1 PED j
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9704070148 970402 i
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JPN -PEL-S ENP-94 -0 79 1
REVISION O PAGE 2 OF 15 f
REVIEW Af0 APPROVAL RECORD I
l PLANT ii. LUCIE UNITS 1
TITLE ASSESSMENT or ECC5 $UCTION PIPIMG CR055 TIE DUE TO DE51EN 6F MaOH SMtAY ADOfTIVE SYSTEM LLAD DISCIPLINL LICENSINC PRODUC' IDS E.Ginrr qws ;gregy N
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JPN-PSL-SENP-94-079 REVISION O l
PAGE 3 OF 15 j
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TABLE OF CONTENTS s.
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4 Table of Contents l
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and Description l
I' 1.0 Purpose I
l
2.0 Background
3.0 Design Bases 11 l
4.0 Analyses of tne Event t
14 I
5.0 Conclusions 14
.0 Verificat on Summary 15 7.0 References l
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JPN-PSL-SENP-94-079 a
r REV!SION o PAGE 4 OF 15 l
3 PURPOSE AND DESCRIPTION te is t o assess the signi t iconce The purpuse c: this evaluation cccc c uv. i r.n safety a rociated with emergency plant operation and c he coct ion piping crosstle due t o the design of
=>=tc; i ECCS)
J.9 O c t t+m
.o Sodium Hydroxide (NaOH) spray additive systen 1994, Unit ; was in Mode 1 ano operating at 100% power.
Di!!erentic; prest are res: ting of a motor cperated va;ve sulteo In the 1;t t :na c:
sa!.ny re;;e: va;ve or t he r.uction nt the ECCS supp;) nem:e r.
er cetooe 2,
ivv4 c :n.ttai ssessment o: Operec1.;ty. Ret cetermineo that t r.
.atety re ;e:.alvt concitin.s and rest;;. r.
sump could litt under certain accident l rah.
.r excess reactor auxiliary building Inventory loss to the l
ECCS design external system leakaue.
of
.0 DAQKGRotTND rotor operatec used te pericre the i
l Examination of the alignment o: the ;P valve test revealed a !!ow path tror the discherce the
'A cont a i nnent spra) l spray pump te the suction et containment system.
pump through a common header in the NaOH spray accitive the A spray pump operat;ng anc all of i
With the IB containment Jommon tc the A train ECCS cuction piping, l
ECCS pumps secured, was pressurized through a spray additive the min ECCS pumps, investigation of the event,
.ommon line.
As pa t of the B
the 1B low pressure safety injection pump was aligned to the svsts train containment spray header and discharged through the B lifting of exchanger with the same result, snutdu-n eccling heet 1
the A train safety relief I-SR-07-1A '60 psig lift setpoint).
l the 1A low pressure safety
.ne maximum pressure observed at This event was injection discharge header was 80 psig.
documented in St. Lucie Action Request (STAR: 1-G4100259 (Ret 4).
The initial assessment determined that the components affectea by the pressurization are capable of withstanding considerably 4
the suction piping and higher pressures (Ref 3).
As such, l
components were not adsersely affected as a result or the event.
However, with regard to the issue of system design, conclude it was in an The existing design could result ECCS suction header relief valve lifting for the event consisting a design basis event.
with a loss of off-site power (LOOP) a LOCA (SIAS and CSAS)
(EDO) failing to operato.
of and one cmergency diesel generatorvalve em Id potentially release containment sump (RAS) which is This relief inventory following recirculation actuation outside design basis event bounding conditions for ECC5 external This system leakage (Ref 2, Section 15.4.1.7, and 15.4.1.8).
scenario esuld result in a condition m tside the accepte The system design condition Table 15.4.1-2, Section 15.4.1.7).
has existed dince the HaOH spray additive system was backfit to Unit 1 in 1978 (Ref 9).
Based on the initial assessment, plant management made a one hour non-emergency notification to the 10 CFR 50.72.
Nuclear Hegulatory Comnission in accordance with I
Y Gk%M y h t ti I k W C-L 1
(a r~) - DMM h d% nC Y fj[ h,
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saf ety(' ova)u tt n /Ref !t) sme t,
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Foll sing the gpit al osse hacher pressures in\\khe ECCS suction l
_deterr,ined AQc (tibi l ity of valves I-SR-07-1A and *-SR-07 I
. piping in order to dise.b:e rellet
! cycle t ai proximately 'I week)
This 1R for the remaining Unit implementeo to precluds the pces'i2 ity of interin measure was The NaOH spray additive system eductor excessive ECCS leakaoe, refueling outage to eliminate piping was med111ed during thc 1994 l
the cross conneet.drscribed herein.
The safety rellet valves have been aniurned te.ers:ce A design reslow.Or tratr. erodo connections was per!ormec f or line identit lec in the NaOH l
identitled nn other train cros's l
ECCS (Ref
't Except for the common tne review spray additive system, connections which do not meet single failure criteria as applioc to St. Lucie Unit : &
2, as discussed in the respective *FSARs and
'DBDs, the de81on basis documents current versions o:
~ ~
[ The architect engineer. Raytneen Enoineers & Constructors t
(Ebasco), was notifiec of the.NaCH spray additive syster ceston s
lette: (Ret ;t This letter requested that
\\ deficiency by aRaytheon review the design
- or ;O CTR Part 21 signi:1cance.
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submitted describing the evettt
~_
'ayse, and some of the preliminary analysis (Ref 6t[ As)
I A'Lic~e~niWW Event Report LER; was i
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the LER corre-tive actTdnsran assessment-o M he safety
- e root This i
/ consequences and implications of this design is required.
w o engineering evaluation is a basis for that a=======nt and will be used as a source document for a supplemental LER.
~
This engineering evaluation involves engineered. safeguards is therefore class 111eo as safety related.
systems and 3.0 DESIGN BASES REVIEW ECOS Desion Bases (Ref
- 2. Section 6.3.1.11 The esargency core cooling system is designed to provide core cooling in the unlikely event of a LOCA for all postulated pipeThe breaks in the RCS.
for design of the ECCS:
be a)
The safety functions defined in FSAR Section 6.3.1.1 must failure of e single active accomplished assuming theinjection mode of operation or the component.oring the single failure or an active or passive component during the recirculation mode of operation.
The design of the safety injectidsystissi~isasfprovies Tur 11.spection and testing of components and subsystems to b) ensure their availability and reliable operation, injection system and associated c)
All components of the safety i
critical instrumentation which nust operate following a LOCA are designed to operate in the environment to whach tney usuld be exposed in the event of a LOCA.
k
11 JPN-PSL-SENP-94-079 REVISION O PAGE 6 OF 15 s
d)
All components of the syster are designed as seinmic Class
- I to withstand the forces of the design basis earthquake t
l (DBE).
.c.. r..
- a. n
- T,i avainated ene des a cr
- the ECCS
. +
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.e.e..n.e n.
..i n.,
and determined that "The ECCS subsystems provided are of sucn l
number, d.versity, reliability, and redundancy that no single 1
)
failure o' EcrS equipment occurrina duranc a I.OCA W11; result ; r.
inadequate coolina c: the reactor core",
Tne s.r.gle : allure analysis is de:.cribec in the FEAR, sect.or.
a.
anc istle e,-
l*
3.
In add 1!.an, ECCS design requirOc t hat
.tb calculatec coo;1nc j.
perf ormance evnt orm te criteria set :crth
.n subparagraph (b) et Section 5C.40, 10CFR Part 50, Acceptance Criteria !ct ECOS !cr i
Light Water Cooled Nuclear Power Reactors.
Supp;ement to the i
SER (Ret 10 Section 6.3) concluded acceptablilty of the ECCS l
performance, and therefore acceptab11;ty el the ECOS, l
The ECCS suction piping is designed ;r. accorcance witn :ne j
requirements of USAS 531.7-1969. Class 11.
The code does not g;
provide a specific requirement tor relieving capacity ir this i
portion of the system.
The relief valves of concern are not j
specifically addressed in the FSAR.
However, the relief valves
~
were installed to address a concern over the interf ace between I
.ow pressure. suction piping and the portion of suction piping used for shutdown cooling.
This protected against leakage across motor operated valves and/or the failure to isolate this portion l
of tha system prior to initiating shutdown cooling (Ref 5).
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ECCS External System Leakage
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External system leakage for ECCS components is described.in the L.P. Safety In]ection/ Shutdown Cooling " Trial-Use" Design Basis Document (DBD-SDC-1).
It discusses ECCS external system leakage i
j due to a passive failure during the recirculation phase following a LOCA as limited to leakage through a failed pump seal or valve i
packing.
Gross failure of ECCS piping is not considered credible.
i 1
FSAR Section 15.4.1.7 and Table 15.4.1-2 defines leakage from engineered safety features (EST) components outside containment.-
e The maximum leakage to the ECCS area is defined as 2 liters per I
heur.
All ESF cosponents containing recirculating sump water are j
within the controlled ventilation area served by the ECCS area
{
ventilation system (Ref 2, Section 9.4.3).
1 1
The design flow of the spray additive system eductor is 12s qsyn (Ref 5).
The eductor design flow and the relief valve capecity are approximately equal with a relief valve differential pressure of 60 psid.
This is consistent with the pressure of
~
approximately 80 psig observed during investigation of the event i
I acing the 15 LpSI pump _(Ref 3).
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i 1
1
J PfJ - P5 L-S EN P-9 4 -0 7 9 REVISIOf; O l
PAGE ~ Of I '.
The safety reite: valve RAB post-LOCA leakage environment a!I c e nr. ; d r r.
- T r rr"l2t t en 'e t a" tampararure and dose.
A review of the scena: ;ct and the estimatec dose indicater that equipment potent al's a!!ected by the leakage would operate itLin the bounds c: 'autation :one maps evaluatec in tne
- tan.ricure
.ent;1ation Based On the oeslan of the RAB and the ECCS area I
syster, the.tafety related equipment locatec within the RAb aren potentia.
.:'" ted by the leaxage operates w:tha n t ha bounos c:
fat:on FC:
A;theugn RAF F.;.
meeta;
.s.
cnvirc m>
.~e : t snchoereo c Aic e.'ertue.2-w en<. r c e uncont:
.r
",i
- a a e.
- satety "ta -
- e 1u.p: ent, result. a.. tota.. o s t.
FS
"* v e r s e i y := pact acc; cent
.a t ;g a t i c r. ca p e t.. ; t y.
ecolina. ana Tha RAB ticer area whicn incluces the pipe tunnel is providec j
via the waste l
wt.n plumbino and drainage norcally controlled management Systen.
An alternate path, describec
.n FSAF Uect;cr
.1....
returnt rauloactive leakage Iron.the ECOF pumf drea *:
the containne"* Lu.iding.
This alternate patn :s tne. e n e.a o e ecilectier and return systen 'LCRSi, a decicatec syster.n : et.
4-aligned t<
the reactor arain tank.RCT' c!!owanc :.A:
be:..
The LCRE requirer anstrument a:r anc non-vita. powe:
Th.s system utill:es the safeguards pump roce sunp pumps ;; punps per train; to pump back to containment.
Eacn samp pump has a aesign operating 11ow. rate of 50 gpm at 100 ft. of head.
The sump pumps sre powered via non-vital MCCs 1A2/1B2 which would not be available during LOOP scenarios.
containment spray discharge header pressures vary depending upon scenaric. however, NaOH eductor flow rate is relatively insent s ;1ve to motive pressure. - A leakage rate of 128 gpm is theref ore assumed in conjunction with LOOP (no sump pumps available) in evaluating effects.
The RAB f loor area ano pape tunnel :loor area can contain the volume of water fro a safety reitet valve discharging 122 gpm fc approximately hours without adversely affecting the idle ECCS train (tra:r. affecteo by Joss of power /EDG failure).
The operating train as protectea from flooding for apprcximately 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br /> assuming wall penetrations separating A & B trains remain watertight.
Leakage if left unchecked could eventually subme'rge the operating safety related equipment, resulting in the total loss of ECCS cooling, and adversely impact accident mitigation capability.
1
-ECCS_ Area Ventilation (Ref 2.
Section 9.4.3)
The ECCS area ventilation system is designed to provide post-LOCA filtration and absorption of fission products in the exhaust air from areas of the RAB wtlich contain the following equipment:
a) containment isolation valves; b)
Low pressure safety injection pumps; Hiah preusure naiety injection pumps;
.;nt a. s.nen:
ora) pumps; e,
- ,hu t uo.n heat exchangers; f
i1p:nu which contains recirculatinu c ont a i nr.e n t un;;.ater rollowino b LOCA.
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JPN-PSL-SENP-94-079 REVISION O L
i PAGE 8 OF It l
J
,The ventilation system is cited to maintain a slightly negat2ve in the engineered safety features area with respect to pressure tha
/ surrouncing aread uf t!w F.A C.
f.' pen Icss nf normal power..
/
system will be auton.atically connected te the emergencu power source if required to operate.
The fans and d9mpeee associatec
/
with each of the separate tilter trains are powered fron separate buses and receive actuation signale from separate SIAS channels, j
l No single faibire will prevent both trains from operating.
l
/
The ECCC equipmen' area is ventilated by passino outside air l
l through it.
ihe. 'J S area ventilat.cn system maintains the ECcr equipment area at a negative pressure, thus, lodano activity l
associated with any ECCS or containment spray system equinment 1
j leakage is passeo through the ECCS system charcoal absorbers,
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,-A'best estimate dose assessment was perforced to evaluate cose j
s i
i g
LOCA assuming the current design of the spray [.
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consequences 0: a I'1). -DTaTia~t i'crT~df ~ the' sou rce terms l or'Th
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)
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additive sys,ta Q 'e!
I s -
accadentw eenarios ihcriretes that r.c core damage ( pea t. clac l
temperature ~2,200 F: would result since one train of ECCS j
operates to' cool the core and ECCS performance is not degradeo i
(Ref 8).
As such, the following assumptions were considerec tor i
determinacion of dose.
1
- )
100% of the fuel rods fail, 100% of the gas gap is released inside contair.4ent.
This is conservative since one train of ECCS operates and meets ECCS performance criteria with only 1
limited fiel clad damage predicted.
i b) 93% of halogens bound as Cs-I, and are not available to become airborne in the ECCS room.
l c)
The recirculated sump water temperature is assumed to remain above 212 F.
This allows for a partition value of 10.
This is conservative since the sump water is recirculated'through the shutdown cooling heat exchanger and would remain less than 212'T (Ref 2, Section 9.4.3.3), at which a partition factor of approximately 100 woulo be more appropriate.
This enhanced partition factor reduces offsite dose by a factor of up to 10.
Filter and iodine removal efficiencies are nautinally 894.
d)
This is conservative since actual removal efficiencies are tested to 99.9%
The results of the above assessment indicates that the offsite dose is less than 1/10 of 10 CFR Part 100 limits.
Ttse dose to the exclusion area boundary and the low population some remain wit' in a small fraction of 10 CFR Part 100 limits and the does to m
the control room would not exceed the conservative vklues described ir the FSAR.
However, radiological consequences could increase if flooding left unchecked results in the total loss of ECCS cooling.
I-JPN-PSL-SENP-94-079 REVISION O PACE 9 OF 15 Containment Sorav Desian Bases (Ret 2 Section 6.2.2.11 The containment neat removal syster consi::tr. c! the conta i r ment spray system and the containment cooling system end is designed to prevent the containternt pressure f rom exec.scing its design value following a LOCA, assuming a single active or passive failure.
The containment
- pray system consists of two independent and redundant subsystems.
The heat removal capacity' of either of t.
two sut.c,* stems is adequate te keep the containment pressure and temperature below design values and to bring the containment pressure below 10 psig within 24 hcurs after any size break in the reactor coolant system piping up to and including a double-ended bret,k of the largest reactor pipe, assuming unobstructed discharge from'both ends.
Any of the following ccabinations of equipment will provide at least minimitm heat removal capability necessary to li.mit and reduce the post-accident containment pressure and temperature:
{
a)
All four. containment fan coolers b)
Either of the two containment spray subsystems c) one containment spray subsystem in conjunction with twc containment ftn coolers The containment spray system has two modes of operation which are:
a)
The initial injection mende, during which the systen sprays borated water from the ref ueling water storage tank-into t containment.
b)
The recirculation mode, which is automatically initiated t the RAS after low level is reached in the refueling water tank.
During this mode of operation, suction for the cpre pumps is tras the containment sump.
containment spray is automatically initiated by the contairsment spray actuation signal (CSAS) which is a coincidence of the safety injection actuation signal (SIAS) and the high-high containment pressure signal.
The SER (Ref 10, Section 6.1 & 6.2.2) evaluated the design of
=4n ed safety features (ESF) which includes the contairinen' spray system. She 6 -hh that the contairmand spray system meets single failure criteria.
4.
5
l i
f JPH-PSL-SENP-94-079 i
REVISION O PAGE 10 OF 15 l
')
An evaluation was performed to assess the impact o t' reduced containment spray flow on the transient safety analyses and the l
containment analyses (Ref 6).
Assuroing the loss of flow to be it ': cetermined that l
j l
limited to the design flow of the eductors,
(
l a reductacn in centainment apray flow of 128 que has asi j
l insignificant effect on the transient safety analyses.
.Additi7nally, pump performance testing (required by Section IX, IWP-32?O) demonstrates that the pumps deliver greater than the required flow of 2700 gpm (assumed in analyses) plus the 128 gps
. With the margins available in the current j
l loss due to leakage.
be l'
analyses,.he design limits for these parameters will not l
exceeded and do not adversely affect accident mitigation capability considered in the analyses.
Additionally, the containment spray flows (77% degraded) used in the containmant analyses are conservative with. respect to the actual pump flows.
j It was concluded that no design limits would have been violated.
u NaOH Sorav Additive System Desian Basec (Ref
- 2. Section 6.2.6.11 The NaOH spray additive systen is designed to operate in conjunction with the containment spray system (Ref 2, Sect. ton 6.2.2) to remove radio-lodines from the containment atmosphere j
i following a LOCA.
The containment spray system provides the supply water for the spray additive eductors.
The spray additiw system is desiq7ed to the following criteria:
j Maintain the containment spray solution pH to achieve rapid i
a) absorption of radio-iodines with minimmi caustic corrosion l
of materials and protective coatings within the containment.
j l
Maintain the containment spray system nozzle spray pH 4
b) between 8.5 and 11.0 until such time that a Decontamination Factor (DF) of 100 is achieved, Achieve a containment sump pH equal to or greater than S.5' c) but less than 11.0 after all the spray <-h==ical mixes with the available water inventory including, Ettrr, safety injection tanks, horic acid makeup tanks, and the reactor
(
coolant system blowdown to assure retention of iaM no in th sump solution.
j i
Remove elemental and particulate iodines with the minimum d) first order removal coefficient in accordance with WASH f
1329.
Indina. Form First Order Damnvatl coefficient
- S$5l*bh;i.e;;
&g 3q,m'*1
- ~,. ~
0.45 hours5.208333e-4 days <br />0.0125 hours <br />7.440476e-5 weeks <br />1.71225e-5 months <br />'*
l Particulate j
e)
Minimize the possibility of precipitation of the spray i
solution within the system or its inadvertent introduction l
into the. refueling water tank.
4 B
4
- I,
l' i
1 JPN-PSL-SENP-94-079 REVISION O PAGE 11 OF 15 f)
System materials are chosen for compatibility with sodium hydroxide.
4 9)
Seismic Category I, Quality Group B, and f unct2 on u.<' r post-accident environmental condit.icne (bc=cd en locatinn).
h)
Perform it function following a LOCA, assuming a single j
active companent railure.
it i
The S"'R does not discuss the NaOH spray addit ive system since l
was a backfit to Unit 1.
The FSAR (Section 6.2.6.2.1, Ref 2) l provides discussion of the design considerations for the spray J
additive system and concludes that the system meets single failure criteria.
l 4.0 kNAL*f81B OF TRr rVrNT of the The following discussions fore the bases for assessment safety consequences and implications of the as-built NaOH spray j
additive system design.
l For the scenarios postulated below, the NaOH spray additive r
- design does not impact the likelihood of a 1DCA event.
As a tr:.dt of the design,.anly the radiological consequences increase when considering design basis events.
As such, the hamaliene core damage frequency for St. IAacia remaina *= *mmurad by f
Bosever, leak before the NaOH apray additive design defect.
break methods which have been approved by the IGic for St. Zaacie l
(Ref 13) have shown that large break IDCA scenarios are not
]
Nevertheless, the three design bases scenarios credible.
i i
described in the FSAR are those evaluated for significanoe to l
l plant operation and safety.
naarian Rania Event - Scenarios i
Three FSAR design basis events are dia==ad below whits illustrate offacts of the NaOH spray addities eductor piping and j
how ECCS suction piping pressurization could be managed assianing 128 gym laakage:
i tarce Break LOCA With IDOP and One Failed Dianal 1.
One train of ECCS equipment would be operating due to the f ailed one containment spray pump would start early in the
- diesel, The idle ECCS A ss M, event as a result of high containment pressure.
iemment
' spray w,'7-pouad be.pressurised by the opegating contavia 'the
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JPN-PSL-SENP-94-079 REVISION O PAGE 12 OF 15 l
(Double Ended Cold limiting large breax LOCA presented in FSAR Section 15.4.1.1 CSAS wouldidle EC j
In the case of the l
Leg Guillotine) injecLicn pha-e ett the a vent poLh actuate early in the In this scenario, Lhe LPSI pump i
l header would be pressurized. train's suction piping ihrcu /
The relief S.
exists Itom the idlato the RCS via safety in3ection piping fullcwing RA
/
spray of the available containmentwhen the av lift U N n start j
valve mau 1
woul? ce expected to ressat RAS.
A calculation (Ref 15) shows that the l
pump, but i
is sufficiently l
pump is secured at path to the RCS vent The pressure drop through thetne safety relieffor RCS/ containment b valve would reseat.
l t
small such that lieve through l
calculation determined that than 38 psi the idle ECCS suction header would re 1
15.4.1-27 shows that f
FSAR Figure the ECCS piping to the RCS. drops below 30 psi approximately 2 minutessafe containment pressurt, In this scenario, J ECCS l
following th'e large break.be expected to challenge the operati
(
leakage would not this event would not be made more l
train and the consequences of l
severe.
Sume Valve Fallina to Open l
Laroe Break LOCA With i
n' 2.
Both trains of ECCS are initially actuated in this scenar o a At this point one train of ECCS 1r operate until RAS occurs. lost as a result of a containment recirculatio l
The idle ECCS suction piping is then j
OH pressurized by the operating containment spray pump via the failing to open.
spesy additive eductor piping.
a RAS l
In this scenario, RCS pressure would be sufficiently low at lift.
'Itne such that the safety relief valve would notconsequences l
Not Actuate Contahament i
===11 Break IDcA With IDOP Which E-rr i
3.
In the case of the limiting small break Lock (0.1 ft )
as l.
described in FSAR Section 15.3.1.3, the injection phase of the flow accident continues for apprawimately 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />
{
S i
control room operators use EDP-03, Imss of Coolant Accident (Ref 12) to stabilize conditions and provide core i
i Core cooling is accomplished by the safety inject on l
procedure or by system or shutdown cooling in accordance with EOP-03, cooling.
i exiting ECP-03 to procedure OP-1-0410022, it Since decay heat would be low sev.aral hours into the event, The to coal the core using shutdown cooling.
Th 4fould be f **M~AsL4tagemeest.dn,FS&R Section 6.3.
fter plant could entar shutdown ensi12mplesMenenwem41/2 houri hW i
^
i the start of the cooldown.
However, should the plant idle train from being pressurized.
ump in a enter recirculation phase with the containment spray p spray pump piggy back alignment to HPSI pump, the containmentin leakage v;a t idle train and result would pressurize the time the ECCS sump alare l
At that
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JPN-PSL-SENP-94-079 REVICION O PAGE 13 OF 15 annunciates and alerts the control room operators to the leak path.
Shutdown cooling system alignment would be identified as tus mathed for icng ter= cccling.
1 Possible success paths have been described for egcific limiting FSAR design basis LOCA events, however the rull spectrur or inca events hav not been evaluated.
LOCA scenarios would require activat.on af the on-site support centers; the Technical Support Center (!SC) and the operational Support Center ioSC).
The following discussions present leakage identification anc
~
strategies which could be carriec out in LOCA scenarios to mitigate the effects of the sarety relief valve leakage:
1.
The control room would be aware of ECCS room flooding due to
]
relief valve leakage via ECCS sump level alarms and RAB radiation monitors in alarm.
1 2.
Control room operator detection of system leakage sould occur by procedure (Step S, EOP-C3 LOCA, Ret 12).
This procedure step addresses identificatler. o: a LOCA outside cf j
contai,nent and directs operators to locate and isolate the i
leak.
3.
It is likely that the safety relief valve leakage would be identifisd early in any LOCA event by operations and/or
)
Technical Support center and action taken to isolate the leak.
The isolation of these safety relief valves could be i
accompiinhed try dWM inn the relief valves or by isolating the NaOH spray additive eductor piping.
4.
Praamahwal steps direct use of the lists to pump back leakage to containment.
In LOOP scenarios, it is reasonable to assume that power would be restored to the sump pumps using jumpers or by re-energizing non-safety electrical buses in the hours that are available before flooding challenges the operating ECCS train.
5.
If safety relief valve leakage occurred during the recirculation pheme of an mar *idasst and done rates in the R&B prohibit ECCS pump room entry, it is reasonable to moeune that the root cause of the leakage could be determined and a strategy implemented to protect the operating ECCS train from flooding.
The control room operators and emergency response organization would have is hours to diagnose and remedy thia situation before any active ECCS train degradation would occur.
Whikmag can A%s13eadirIbadin the PsaR have boon'ml meets Junwa -teen A
~
er riemed, the lack event reviewed and it is concluded that tiw consequences of thsse events weald have not been maos more severe as a result of the NaOH spray additive piping design.
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i JPN-PSL-SENP-94-079 REVISION O PAGE 14 of 15 5.0 COMCLUEIONS 1
14CA scenarios are considered low probability evente for the
+
i large double ended break or not credible, howevel cney are j
Iunoamental assion casts events tnat are accommoaated in the St.
l Lucie plant design.
Arguments presented in this evaluation demonstrste that the consequences of the above specific analyzed design b. sis events would not be made more severe than FSAR assumed analyses as a result of the NaOH spray additive piping 4
design.
T;11s evaluation ch a identif.es the flexibility of plant design which would be drawn upon in an emergency response i
situation to'matigate the erfects of ECCS suction header pressurization.
ECCS would be able to accomplish its intended function based on the events considered in this cvalustarn.
The results of the dose assessment indicates that the offsite dose is less than 1/10 of 10 CFR Part 100 limits.
The dose te the exclusion area boundary and Ine low population zone remain i
within a small fraction of IC CFR Part 100 limits and the dose to the control room would not exceed the conservative vslues t
described in the FSAR.
'~
YERIFICFsTION
SUMMARY
j The moops of this verification was to review the imputs to j
determine if the results were reasonable.
The method need for i
thir. verification consisted of ensuring that the applic Wie references, codes, and regulatory requirements were idend find i
and addressed.
The inputs are correctly selected and appi W.
4 The conclusions provided are reasonable with respect to the i
inputs and discussions.
The verifier concurs with the N=-1=ar
]
Safety Related classification of this Engineeriaq Emmiumeina. The i
rationnie in assigning the safety classii'ication wem verified j
against the requirements of JPN Quality Instractions.
The 2
verifier annenes with the conclusions ont14aad above.
1 a
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JPN-PSL-SENP-94-079 i
REVISION C f
PAGE 15 OF 15 l
(
i 74 ENCES j
g St. Lucie Unit t tecnnical specifications, amenoment ho. av j
[
i f
j Mt. Lucie Unit'1 FSAR, through Amendment No.
11 1
h l
7 3.
Initial Assessment of Operability, " Operability Assessment of Safety Relief Valve SR-07-1A Lifting", dated October ~3, 1994 i
4.
St. Lucie Action Request (STAR) 1-94100259.
f l
[.
St. Lucie Unit 1 Safety Evaluation, JPN-PSL-SEMP-94-076, Rev. (
j
" Increase of Engineered Safeguards Suction Piping Design i
Pressure".
6.
Licensee Event Report (LER)94-006, Rev.
O.
i l
7.
Inter-Office Correspondence, JPN-SP-94-152, NaOH Cross Connect 2
{
Design Review, Dated October 31, 1994.
l 8.
St. Lucie Unit 1 Engineering Evaluation, JPN-PSL-SEFJ-94-033, l
t Rev.
O,
" Assessment,of Safety Consequences of a 128 GPM l
Reduction in Containment Spray Flow".
1 i
).
St. Lucie Uni' 1 PC/M 231-77, NaOH System, dated March 3,
- 1978, i
10.
St. Laacia Unit 1 Safety Evelaation Report (SER) and supplements I
& 2.
m 11.
Inter-Office Coss-EF.Grl!ence, JNO-NP-94-058, Does Assessment of i
Additional ESF Tmkmpe, dated November 8, 1994.
12.
Emergency Operating Procedure, 1-EOP-03, Ioss of Coolant Accident.
l 13.
NRC letter to J. E. naldW, St. Imcis Units 1 & 2 - Applicati t
af Leak before Break W1agy to Beactor Coolant System Pipir
- TEC 508. MS4560 and NB48E1, dated March 5,1993.
1 l
14.
Deleted 15.
St. Lucie Unit 1 =1-1=tism, Pdte1FJN-94-019, Rev. O, LPSI l
System Pressurization Response Due To Common NacB Spray Additis Injection Crosstie, dated November 30, 1994.
l 16.
FPL to Raytheon Engineers & Constructors, JMN-JB-94-072, St.
j Lucia Unit 1 NM masard scos speny additi W ^'--'
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