ML20137L077
| ML20137L077 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 08/27/1995 |
| From: | FLORIDA POWER & LIGHT CO. |
| To: | |
| Shared Package | |
| ML20137K821 | List:
|
| References | |
| FOIA-96-485 JPN-PSL-SENP-95, JPN-PSL-SENP-95-103, NUDOCS 9704070150 | |
| Download: ML20137L077 (10) | |
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i JPN-PSL-SENP-95-103 REVISION O l
PAGE 2 0F 10 4
I REVIEW AND APPROVAL RECORD j
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ST. LUCIE UNITS 2
- PLANT .
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TITLE Evaluation of Relief Vrive Performance !
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I. LEAD DISCIPLINE LICENSING
- ENGINEERING ORGANIZATION PRODUCTION ENGINEERING GROUP
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. REVIEW / APPROVAL:
i j INTrnFact nPt VERIFIED APPE0rtD FPL APPWVfD*
j GROUP PREPARD l INPUT afvtty n/a MMM Mmq M l HA JA L j utn ELECT I // g4 ,4// f thC I- M4 W$ N$ >
l civil I A/A #4 NI LIC" LEAD W Y"] l mth $$$ A nr x 'yn MA n Aff n nuc FutL x pp pd If W PSA I A/) NA E y
- For Centracter Evals As tetofwined By Projects " Revios interface As A mn on All 10&R50.5 Evals and PLAs CHIEF NECH. ArrROVAL:
I6 NA DATE: s1/W cs Er uC. Armonu n, mm om, r,/ oar I
'54/ 6 ret moo.ECTs ArnovAL: , &, w we oATE: 1 . . .
JTHER INTERFACES Mone ,
JPN form 24. Rev 9/92 ,
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l JPN-PSL-SENP-95-103 l REVISION O j
- PAGE 3 OF 10 1
' l TABLE OF CONTENTE FAEE SECTION TITLE F. AGE l
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-- Cover 1
-- Review and Approval Record 2 l
-- Table of Contents 3
- l Purpose anu Scope 4 ;
1.0 Design Bases Review 4 2.0 3.0 Evaluation 5 l 4.0 Planned Improhentets 9 5.0 Conclusions 9 1
6.0 Verification Summary 9 l
7.0 References 10 Attachments ;
- 1. Safety Relief Valve Review Sheet for v3417 3 pages j
- 2. Safety Relief Valve Review Sheet for V3412 3 pages l l
- 3. Safety Relief Valve Review Sheet for V3439 3 pages j
- 4. Safety Relief Valve Review Sheet for v3507 3 pages l l
e e
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4 l JPN-PSL-SENP-95-103 i REVISION O PAGE 4 OF 10 j 1.0 PURPOSI AMD SCOPE t
! The purpose of this evaluation is to assess the operability of the l
' affected systems for the following relief valves:
i V3417' "A" side HPSI discharge header
I 1 V3439 "A" side LPSI discharge header
! V3507 "B" side INSI discrarge header j These valves were 'dentified as having limited positive " lift i margin" and/or negative "ressat margin", and as such, an
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operability assessment of the affected systems is provided. !
- This engineering evaluation involven engineered safeguards systems i
!; and is therefore classified as safety relatsd.
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! 2.0 DESIGM RASES REVIEW
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i V3417 "A" side MPSI discharae header fRef 21 )
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! V3417 is designed to protect the high pressure safety injection i i header against overpressure developed due to operation of the i i; et g pumps. In addition, the valve protects against the l j pres.ca devel*oped due to fluid thermal expansion and passively ,
- maintains the integrity of the HPSI system pressure boundary. 1 I
i i The design lift setpoint for t.11s relief valve is 2400 psig. 'be .
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' design relief flow capacity f.s 132 gpa. The design ace - dation j and blowdown is 10% and 25%, respectively. The design pressure and 1
temperature is 2485 psig and 350 degrees, respectively.
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> V3412 "B" side MPSI discharm header Tref 21 I V3412 is designed to protect the high pressure safety injection i header against the pressure devtloped due to fluid thermal expansion and passively maintains the integrity of the HPSI system pressure boundary.
The design lift setpoint for this relief valve is 1585 psig. The design relief flow capacity is 5 gpr although the actual flow rate may be as high as 40 gym. The design accumulation and blowdown is 10% and 25%, respectively. The design pressura and temperature is 1600 psig and 350 degrees, respectively.
V3439 & V3507 "A" and "B" side LPSI discharae header Tref 31 V3439 & V.307 are designed to protect their respective low pressure safety injaction line and header against the pressure developed due to fluid thermal expansion. In addition, these valves passively I maintain the integrity of the LPSI/SDC system pressure boundary. .
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JPN-PSL-SENP-95-103
- , REVISION O PAGE 5 OF 10 l 1
The i The design lif t setpoint for these relief valves is 500 psig.
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design relief flow capacity is 5 gpa although the actual flow rate may be as high as 40 gpa. The design accumulation and blowdown is j 104 and 104, respectively. The design pressure and temperature is l l-l 500 psig and 350 degrees, respectively.
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! 3.0 ETALU1 TION Operability assessments were performed for each of the systems that j
could be adversely affected by the unintended lifting of the relief l 1
valves during the most limiting system operating conditions. Each ,
assessment includes a dete mination of the following system and relief valvo performance characteristics:
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- Maximum Operating Pressure: The maximum system pressure during the most limiting expected operating conditions.
Transient Pressure: A conservative estimate of the pressure l
j spike corresponding to the starting of the limiting system pump.
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- Lift Setpoint . Pressure: The minimum pressuru where the relief valve begins to lift.
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- Lift Margin: The margin between the lift setpoint pressure l and the maximum opsrating press.tre when added to the transient j
pressure. A nomitive lift marain indicates that the valve i
'l not lift durina the asst limitina ernacted essratina
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8 cmditions.
- Roseat Margin: The margin between the minimum reseat pressure of the valve and the maximur. operating pressure of the system.
A neantive ramest marein indicates + hat thebelowvalvemarimum will not resent unless - tem wessure is r*M operatina nrassure.
- Setpoint Drift: The percentage change in the lift setpoint pressure.
Y3439/Y3507 Lift Marain The determination of the maximum operating pressure included a review of the following operating mode:
l LPSI: highest entry pressure + static head + LPSI
- 1) shutoff head (462/458 psig for V3439 and V3507, l respectively)
Calculatio: s using a transient pressure of 30/30 psi (e.g., the starting of a LPSI pump), a maximum operating pressure of 462/458 psig and an actual Jift setpoint pressure of 510/505 psig, determined a lif t margin of .+18/+17 psi for V3439/V3507. (Refs 8 l
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l l JPN-PSL-SENP-95-103 REVISION 0
! PAGE 6 OF 10 i
{ and 9) (See planned improvements for spacific actions to increase lift margin.)
! Rasent Marcin calculations using an actual setpoint of 510/505 psig, a blowdown of 104/10% and a maa.igua operating pressure of 460/455 psig, i
j determined a ressat margin of +24/+19 psi for V3439,MS07 (Ref S&9).
setnoint Drif*-
l The work history for these valves indicatas that they are not prone l
to drifting below their lift setpoint, and therefore, they wculd be
' expected'to lift at or slightly above their setpoint. (Ref 6]
System Ooerability Based on positive lif t margin and limited potential for setpoint l
i drift, V3439/V3507 will perform their function during these operating conditions, and the functions of the LPSI system i (including SDC) are not adversely affected. However, to demonstrate additional assurance of safety, the consequences l
1 related to the hypothetical lifting of these valves has been l
evaluated below. .
s l Consecuences of Liftine V3439/V3507 4
! .. thJs evaluation, the lifting of v3439/V3507 is hypothetically l postulated to occur while on SDC if LPSI pump operation results in i
LPSI discharge header pressures reaching the. relief valve setpoint.
Sufficient pressure to lift *:he relief valve is assumed during LPSI i pump starts that result in a pressure spike. Therefore, this
! analysis only considers operation that involves LPSI di W *ge pressures approaching the relief valve setpoint. (LPSI discharge
] pressures cannot arceed relief valve setpoint during operation with j the shutdown cooling system isolated from the RCS.)
Imse of RCS Inventory 1
l If either of the valves were to lift during normal shutdown l cooling (SDC) operation or during long tern cooling following i l
a design basis accident, the valvas will have positive resent
is established soon af ter the RCS is aligned to the LPSI pump, j and the LPSI pump is started. Therefore if either of the j valves were to lift the blowdown would be limited to the time required to establish normal SDC flow after the pump is i
started and the SDC temperature stabilizes; this is estimated j to require less than 15 minutes. This inventory loss (i.e.,
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= 40 gpa for 15 minutes) is well within normal charging and j arxeup capability.
f Fle.,odine in the "A" Safecuards Puun Room 1
If either of the valves were to lif t during normal shutdown
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s JPN-PSL-SENP-95-103 i REVISION O i PAGE 7 OF 10 I
cooling (SDC) operation or during long term cooling following "A" l a design basis accident, blowdown is piped to the l -fi l jJ Q} yd safeguards pump room sump. Since this sump holds in excess of 3000 gallons and the magnitude of the blowdown is estimated to 34 be 600 gallons, flooding of the "A" safeguards room wi13 not
- s j
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qj Q' occur [Ref 10). Note that annunciation of the high and high-g high sump alarms would require investigation to deter .ine the i q s f
- 3 's.O M reason for the alarm [ Ret 4).
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gQ%' - Radiolocierl Conneauences of Desicm Basis Accidents s.
tV C ., v steam Y,, small break loss of coolant accidents (IACAs), aw ==s
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demand events (F.SDEs) and steam generator tube rupture (SGTRs) are the design basis accidents that are postulated for the 4
dW purpossa of this evaluation to involve the lifting of 4 y a K.
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V3439/V3507 since these events could result in the SDC system being placed in service with maximum suction pressure
- j. j r.
s
,v 'f' m supplying the LPSI pump (s) .
l- ;d j sk ~ sA The offsite dose calculations for the FSAR large break IDCA qtM W
! jf../ M D' D include the effects-ofJLCG--leakage into the safeguards pump room sump. Giased on revMaite doses for the accidents iQN described above (i.e., small break IACAs, ESDEs and SGTRs that l
f dp \ d include additional RCS leakage)
_ _ consequences of the FSt.R large break IDC7 analysis'. ,
are bounded by the
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% s..- . .I{f,Cb p oc y}g fhU h .,
- b (MG gca f75 h/
l Lift Marain hw[t OI The dotaraination of the main at N e included a review of the following operating modes:
peig) i
- pressure + static head (s 1271 psig)
In addition to the above operating modes the following lineup (beyond licensing basis) was also examined:
Alternate charging: normal charging pump operating pressure +
- 3) system static head (2290 psig)
Calculations using a transient pressure of 50 pai, a maximum operating pressure of 2290 psig and an actual lift setpoint pressure of 2400 psig, determined a lift margin of +60 pai. [Reflift 5)
(See planned improvaments for specific actions to increase shrgin.)
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' l i, i 1 JPN-PSL-SEMP-95-103 )
REVISION 0 l PAGE 8 0F 10 j,
i Resent Marcin calculations using an actual setpoint of 2400 peig, a blowdown of 25% and a maxim ting pressure of 2290 psig, determined a ressat margin of 482 pp F (Ref 5). (See planned improvements for j
j specific actions Teduce negative margin.)
Seteoint Drift I
The work history for this valve indicates that it is not prene to j
drifting below ics lift setpoint, and therefore, it would be
{
expected to lift at or slitstly above its setpoint. (Rs. 6) i l
System Ooerability Substantial margin to lift exists during normal system operation.
l Only during alternate charging, which is an off' normal alignment
!- (beyond design basis), is the margin to lift limited. The !
operability of the HPSI and charging systems does are not not adversely consider l impacted. Therefore, this evaluation l
l hypothetical consequences of the valve lifting.
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- -Lift Marein T:-
srmination of the maximum operating pressure included a revis of the following operating modes:
- 1) Eccs Injection:- EPSI shutoff head + RNT static head (1271 Peig)
+ conh i n===t
- 2) ECCS Recirculationt BPSI operating head pressure + static head (1194 psig)
Calculations using a transient pressure of 127 psi, a mawimma operating pressure of 1271 peig and an actual lift setpoint pressure of 1600 psig, determined a lift margin of +202 psi. (Ref 73 Resent Marain Calculations using an actual setpoint of 1600 psig, a blowdown of about 25% and a maximum operating pressure of 1271 psig, determined a ressat margin of -67 psi (Ref 7) . (See planned improvements for specific actions to reduce negat.ive margin.)
Setooint Drift The work history for this valve indicates that it is not prone to drifting melow its lift setpoint, and therefore, it would be expected to lift at or slightly above its setpoint. (Ref 6)
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REVISION 0 PAGE 9 OF 10
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j j j Bystem Operability i f /During the anticipated operating conditions evaluated above, sufficient positive lift margin exists to preclude V3412 from ;
, lifting. Therefore, operability of the HPSI system is not j j affected. This =,v luation does not consider hypothetical i consequences of the valve lifting since it has been l=eonstrated l, [ that the valve will function as designed.
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( N j 4.0 PLEMMED IMPROTEKENfB While the above evaluation de=anstrates that the relief valves will l not adversely affect their associated systems, additional
- conservative actions are planned to be implemented during the j upcoming refueling outage for each of the subject relief valves to
- address lift margin and rassat margin
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' Y2311: 1) Se lift setpoint will be increased from 2400 to 2485 psig. This will increase the lift margin.
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- 2) Blowdown will be reduced to improve ressat margin.
! 22111 1) Blowdown will be raamad from 25% to 10-15%
l providing a positive ressat margin.
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vnagt 6
Ch? 2.1: 1) The litt setpoints will be increased from 500 to 535 peig. This will provide additional positive i
- .y&
s N lift and ressat margin.
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1 i e G, , ? 5.9 m* - .i o
} hWN J: ' h , An assessment of the subject relief valves with respect to the j
qo t'p g -operability of their affected systems has been performed. The
.f c 4J assessment concludes that these relief valves with the current setpoints will function as designed and tested, and will not he C I d s/ adversely affoct safa plant operation during normal, shutdown and design basis accident conditions. In addition, conservative Ni A V' / actions are planned which will improve the performance of these
-yi d'
[% [ valves, thus, providing added assurance the related systems will function as designed.
s .9 6.0 TERIFICATION EMDEARY The scope of this verification was to review the inputs to determine if the results were reasonable. The method used for this verification consisted of ensuring that the applicable references, ciodes, sad regulatory requirements were identified and addressed.
The insats are correctly selected and applied.
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! JPN-PSL-SENP-95-103
! REVISION 0 i PAGE 10 OF 10 l
The conclusions provided are reasonable with respect to the inputs l
and discussions. The verifier concurs with the Nuclear Safety of this Engineering Evaluation. The Related classification i
ratiotale in assigning the safety classification was verified The verifier r
against the requirements of .T*N Quality Instructions.
, concurs with the conclusions outlined above.
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7.0 REFERENCES
- 1) St. Lucie Unit 2 FSAR, through Amendment 9.
l 3 2) St. Lucie Unit 2 HPSI DSD, Revision C.
- 3) St..Lucie Unit 2 LPSI/SDC DSD, Revision O.
! St. Lucie Unit 2 Plant Annunciator Summary, Revision 49 4) l 5) At*.achment 1 a - ..
Plant Work 0,rders: 880 31532,(89016499,
- 6) /890241027,(90024292(, @,21736, 17020589, (5720028308, (900604215 ~
- 7) ' Attachment Y .
- 8) Attachment 3
- 9) Attachment 4 l 10) 2998-o-069, Sht 1; 2998-G-072, Sht 1.
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