ML20137K940
| ML20137K940 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 12/21/1993 |
| From: | FLORIDA POWER & LIGHT CO. |
| To: | |
| Shared Package | |
| ML20137K821 | List:
|
| References | |
| FOIA-96-485 JPN-PSL-SEFJ-93, JPN-PSL-SEFJ-93-024, JPN-PSL-SEFJ-93-24, NUDOCS 9704070126 | |
| Download: ML20137K940 (9) | |
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i FIARIDE PCNER & I.ZCET Co.
I Engineering Evaluation i
! 14ss of Feedwater Transient with corrected sessa Generator Inventory Error e-li 4
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! Engineering Evaluation
) ; Loss of Feedwater Transient with i
Corrected Steam Generator Inventory Error
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JPN-PSL-33rJ-93-024 Revisies 0.
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32 VIEW AND APPROVAL REC 0%D l
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- TABLE OF CCIfTENTS i i
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Covershewt g l l l Desige Zaterface Record 2 ,
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Table et Contents 3 ,
! l l Abstract 4 1.0 Purpose 5 2.0 Licensing Requirements 5 3.0 Evaluation of Re-Analyses 5 l 4.0 conclusions 6 1
! 5.0 Effect on Technical Specifications 6 1
6.0 careviewed Safety Question Determination 7 7.0 se 'arences 9 l
Attachment , Mumber of Paces _
- 2. FSAR Changs Psckage 22 -
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!. #F18-PSI,4EFJ-93-024 -
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i AssTsacT:
i i During a review of the current licensing basis analyses i performed to support the on going steam generator replacement
! project, a discrepancy between the results obtained by Babcock i and Wilcox International Limited (BWIL) and those g ven in the FSAR for the Less of Feedwater event (LOFW) !*s identified.
j[ Upon review, it was determined that the correct initial steam i generator (SG) mass value was approximately 18,000 lba lower j than what was used in the St. Lucie Unit I safety analysis (non-i conservative). This mass error impacts the FSAR Chapter 15 LOFW event and the auxiliary feedwater section of FSAR Chapter 10. ,
, SPC and FPL performed a review to determine if a significant i safety defect existed in the SPC analyses performed and reported in ANF-89-113 (Reference 7.1) . It was concluded that a substantial safety defect did not exist and that the reporting requirements of 10CFR21 vare not applicable (References 7.3 and 7.4).
i The errors were cortacted and a re-analyses was performed using more realistic input assumptions. The corrected results meet all acceptance criteria and are supported by the Technical Specification limits.
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1.0 Puntoss
Two errors were recently identified in the initial SG inventory used the St. Lucie Unit i safety analyses. First, a pre-stretch fu11' stretch) wa9 power SG inventory (about 3,000 lba higher than the post-The second error provided was in as the casts ror 5FC's sarety analysen.
analysis (about 15,000 lbs). tha ,nmputer eness i npist t n t he LOFw The objective of this evaluation is to determine the consequences of these errors in the initial SG inventory and to provide the results of the re-analysis. The determination that a substantial safety defect did not exist and that the reporting requirementJ of 10CTR21 were not applicable was performed shortly 7.4). after the discrepancy was identified (References 7.3 and The re-analyses Transient (Attachment 1) of the Chapter 10 and Chapter 15 LOFW were performed by SPC. The Updated TSAR (FSAR) change package resulting from the re-analyses is included in Attachment 2.
2.0 1.ZCENSING REQUIREMrNTS:
2.1 FSAR Chapter 10 evaluates the adequacy of the Auxiliary Feedwater system (AFWS) based on the requirements of Section 10.4.9 of the SRP and Branch Technical Position ASB 10-1. The criter' reviem *n Section 10.4.9 of the SRP are based on the required 0737. the ATW stated in the post THI action plan, NUREG-2.2 FSAR Chapter 11 Section 15.2.8 reports the results of the Loss of Normal Feedwater riow event evaluated based on Standard Review Plan (SRP) Section 15.2.7 criteria.
3.0 EV1&DA.T20W OF RB-ANAZ.YSEst
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, A 6I,fhe >11miting'- . cases from Chapter 10 and Chapter -.;. . .5.%;.y %
15 oveatstwere
- g. " re-analysed > with the correct initial . SGeinventoryvv*Nore. i n
. realistic; input assumptions were also usedMFor example 7'ther:
@ ? J fechnical S values for reactoru. tripsaetpotatp4.d)i,g
'#F ~'(including .pecification instrumentation uncertainties) d aad Faux 111ary a f -
.Feedwater Actuation System (AFAS) initiation time for AFW were used. The assumptions used are included in Attachment.1. y 3.1 FRAR c'hanter 10 Analvana These analyses were performed to verify adequate AFWS performance when the event is initiated from nominal conditions (References 7.1 and 7.2) . Two cases were analysed; one with
. offsite power
- A Ng' time.; of thee, f SGand- lowanother level where trip..m offsite Assumptions power / .is lostvatsth'mMr.
requirements' b
- includer'.~ nominal operating conditions, an auxiliary feed line break, two RCPs shutoff at 30 minutes, and a limiting single failure (auxiliary feedwater pump) . The results of the re- -
analyses using more reslistic assumptions are included in Attachment 1.
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' Revision 0 Fage 6 of 9 3.2 FSAR chaeter 15 Analvann A disposition of events was performed for all Chapter 15 events (Reference 7.3). 'this disposition identified the LOFW event as the only event adversely it.pacted by the errors. There are two cases censidered la *he chspear 1% analysis, 1) with auxillary _;
feedwater initiated automatically, and 2) with no auxiliary feed turned on. The purpose of the first case is to varify that the ~
SGs do not dry out wit.h automatic initiation of the ArWS. The purpose of the pocond case is to confirm that the operators have 10 minutes to sr. art auxiliary feed if it does not automatically start, as required by the Technical Specification Bas'es.
The results of the re analyses are included in Attachment 1.
4.0 OusC24sIONS
4.1 rsAR chanter 10 Analyses The results of these analyses demonstrate that for the FSAR Chapter 10 LOFW transient, the AFWS is adequate to maintain a
.cecondary heat sank throughout the event. The minimum SG liquid inventory was from the offsite power available case. The l
minimum seconds.
liquid inventory was 15,800 lbm and occurred at 1750 4.2 f."" Ch a e t e r 15 Analvses In the initial analyses (Ref erence 7.1) it was demonstrated that
,. the Chapter 15 case is bounded by the Chapter 10 case, i* Therefore aonfirmation that the Chapter 10 event prevents SG dryout confirms that dryout would not occur for the Chapter 15 case. The results of the Chapter 10 re-analysis demonstrate that the existing margin in the Chapter 15 analyses was adequate to compensate for tho' errors.
1 A sensitivity calcuistion, where no auxiliary feedwater -was Yb injected into
-". about.700 the SGs, indicated that the SGs would empty at M W seconds. Therefore, the analysis results with the db correct initial 30 mass demonstrate that sufficient inventory #F exists in the 80s at the time of the trip to provide a margin of 4/"C .
more than 10 minutes before AFM is required as stated in the f Bases of the Technical Specifications.
S.O EFFECT ON TECENICAL SPECIFICAT!0NS:
There are no ef fect s on the Technical Specifir ations from the LOTW l
- Transient reenalyses with the corrected SG inventory errors. The conclusions supporting the plant license amendment
-(PLA) to reduce the low SG 1evel trip setpoint remain valid (Reference 7.2) . A sensitivity calculation demonstratSd that - "
the specified setpoint provides core protection and that the design pressure of the reactor coolant system will not be i
! exceeded for more than 10 minutes after trip and' before l
auxiliary feedwater is initiated, as required by the Technical
, Specification bases for the low SG 1evel tr'.p setpoint.
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.77W-PSL-SEFJ-93-024 5
Revision 0 Page 7 of 9 6.0 UNREYZXNED #AFTTY QUESTION DETERMIMATION:
i 10 CFR Part 50.59 permits the holder of an operating license to i make changes to the facility and procedures as described in the l
j Final Safety Analysis Report (FSAR) and to conduct fasts or -
exper ,,n,9 nne previously described in the FSAR withr a prior a
l i NRC approval, prcVidad thev do not involve an unreviewed Safety '
i question and do not require a change to the Technical ;
Specifica tion .: . In accordance with 10 CFR Part 50.59, the :
i following eva*uation serves to determine whether this re-
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analyses with the corrected SG inventory constitutes an l unreviewed safety question:
i l 6.1 Does the proposed activity increase the probability of
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occurrence of an accident previously evaluated in the FSAR?
l The re-analyses of the Chapter 10 and Chapter 15 LOFW Transient F
h with the corrected SG inventory do not change the .overall
' configuration of the plant. The mode of operation of the plant remains unchanged. Therefore, the probability of occurrence of l
1 an accident previously evaluated in the FSAR report is not increated, i
j 6.2 Does the proposed activity increase the consequences of an
' dent previously evalusted in the FSAR?
] The re-analyses of the Chapter 10 and Chapter 15 LOFW transient j
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with the corrected SG inventory do not affect any structures, systems c,e components that function to mitigate the consequences l of an accident by containing or detecting the release of radioactivity.
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! Based on the review of the identified.SG inventory errors for all Chapter 15 events, the chapter 10 LorW Transient With -
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- Offsite Power. Available and the Chapter 15 LorW transient -
i w -j ; without ~ initiation of ArW events were determined to . require o, ',
j reanalysis. The results of these analyses (Attachment 1) J '
demonstrate that the conclusions reached to support the reduced l -
low SG 1evel setpoint (Reference 7.2) remain valid, and that no safety limits are violated.
Therefore, the consequences of an accident previously evaluated 1
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in the FSAR are not increased.
! 6.3 Does the proposed activity increase the probability of an j occurrence of a malfunction of equipment important to safety
- previously evaluated in the FSAR?
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{ This activity does not create any spatial or functional interaction with any structure, system or component important to
. safety. Specifically, the re-analysis of the LOTW Transient
} with the corrected SG inventory error does not have a functional j relationship with any systems, structures, and components nor 4
does it create any new failure mode... Therefore, the
{ probability of occurrence of any equipment malfunction important 4
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i to safety previously evaluated in the FSAR will not increase.
j 6.4 Does the Freposed activity increase the <fon=*cmant a nf a i ralfwaction of equipment im; ort ant to safe *y previously
, evaluated in tne t3AMt
!- The re-analyns of the LOFW' Transiants with the ,:orrected SG i
inventory error do not create any tipatial or functional 4
interaction with any structure, system or component important to
, safety. Chapter 15 of the FSAR describes postulated plant transients which could occur as a result of equipment failures.
Therefore, the consequences of a malfunction of equipment important to safety previously evaluated in the FSAR are not
, increased.
6.5 Does the proposed activity create the possibility of an accident.
j of a different type than any previously evaluated in the FSAR7
! Tre re-analyses of the LOFW Transients with the corrected SG
! i 2ntory error do not change the operation, function or design i
bcses of any structures, systems or component important to l
==fety as . described in the FSAR. No new failure modes or ting single failures have been created as a result of this 1
re-analysis. No new hazards are created as a result of the LOFW i Transient re-analysis that can be postulated to cause an
[. accident ditferent from those previously analyzed in the FSAR.
6.6 Doen the proposed activity create the possibility of a malfunction of equipment important to safety of a different type than any previously evaluated in the FSAR?
. , ' .f The re-analyses of the 1,0Fw Transients with.the5c'orrected SG.
in. . t SEF %.' *. ' inventory error do not create any spatial or. functional G." -R ^ F interaction with any structure, system or component important to -
safety. No new hasards are created that can be postulated to cause a malf Jaction of equipment important to safety different from those previously analyzed in the FSAR. Thus, the posnibility of a malfunction of equipment important to safety previously nvaluated in the FSAR is not increased.
6.7 Does the reroposed activity reduce the margin of safety as defined ir, the basis for any Technical Specification?
The re-analyses of the LOFW Transients with the corrected SG inventory error do not change the design bases, functions, or operations of any safety-related equipment and do not adversely affect any other safety-related structures, systems or components. The Technical Specification requirements and bases applicable to the LOFW event with the corrected mass error and more realistic assumptions are not affected. Therefore, this mass error does not reduce the margin of safety as defined in e
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The re-analysis of the LOFW Transient with the corrected N inventory e ror does not impact safe operation of the plant, and ooes not constitute an unreviewed safety question.
7.0 Refersnoes 7.1 ANF-89-113, "St. Lucie Unit 1 Loss-of-Feedwater Transient With Reduced 1989.
Steam Generator Low Level Trip setpoint," september 7.2 FPL letter to the NRC, "St. Lucie Unit 1 Docket No. 50-335 Proposed License Amendment Low Steam Generator Level Reactor ' ., j Trip and Autometic Feedwater Actuation Systen Setpoints,' L W '
46, 3/9/90.
7.3 SPC letter,
" Notification cf Error in Analyses," CJB:93:046, September 27, 1993.
St. Lucie Unit 1 7.4 Engineering Evaluation, JPN-PSL-SEFJ-93-018, Revision 0," Steam Generator Inventory Error SSH Determination Checklist," 10/1/93.
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