ML20235X379
| ML20235X379 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 09/16/1987 |
| From: | TENNESSEE VALLEY AUTHORITY |
| To: | |
| Shared Package | |
| ML20235X316 | List: |
| References | |
| SQN-SQS4-0088, SQN-SQS4-88, NUDOCS 8710190333 | |
| Download: ML20235X379 (36) | |
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ENCLOSURE 1 1
SQN-SQS4-0088 Justification for continued Operation wif.h j Unimplemented Corrective Actions for Moderate Energy Line Breaks. i i
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' ' ' TVA 10697 (DNE-0A--86)
' DNE CALCULATIONS M' -' Y h M !
l Title JUSilFICATION FOR CONilNUED OPERAil0N WIIH UNIMPLEMENTED CORRECTIVE l Plant / Unit ACI10NS !
l FOR MODERATE ENERGY LINE BREAXS l l SQN Unit I and 2 l KEY NOUNS (Consult RIMS Descriptors List) l ggg ClPreparingOrganization 3 ranch / Project identifiers
) Justification, Floodino, Pipe Breaks (Each time these calculations are issued, preparers must ensure that the i
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loriginal (RO) RIMS accession number is filled in.
lSQ4-SQS4-0088 lRev (for RIMS' use)
RIMS ACCESSION NUMBER R0
!B70403c0068 ! #45 97 0327 l^gO' l i$" '""""
l a, I 426{
l SCR SQNNEB8617 (S9 (#2) l l l 845 '87 0916 426 l
l 1R 1 l
lSARSection(s) l UNID System (s) l l l 3,6 l N/A lR I l
l l Revision 0 ~l RI i R2 i R3 ISafety-related? Yes (x) No ( )
lECN No. (or indicate Not Applicable)l l l_N/A l lStatementofProblem l I l !
l aryd (#d,odtis.d ll Prep /a w, M d 8/2$ v l l The purpose of this safety evaluation is to 7- 45'" F i Nr-pr l l l
l provide a justification for continued opera I lChecy//
l_ cf . P2#~ O l j Y"j j l tion (JCO) with unimplemented corrective l 1 l actions for moderate energy line break lReviewVd V V l_ -6b 2./m d!1(I7 Nll/d l
I l break (MELB) flooding in (1) Mode S before l restart and (2) Modes I through 6 until the j l / 1 l
b ~~O h *)llbl ?
SE FORM l List all pages added l ;
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/A10534)bythisrevision I l l l l
llf MORE lListallpagesdeleted l l l
l l SPACE lby this revision i I l
l I l l REQUIRED lListallpageschanged lg l lby this revision l l l ABSTRACT l 9 ll l l l [These calculations contain an unverified assunption(s) that must be verified later Yes p No(p] l t.
l l in orderg provide as safety assessment of the currentevaluation .
situat (4 l Base'l on this evaluation, there is no safety concern associated cycle 5. l l ;;; cit;d d t' ;!!her ;;;ncrio Q l
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I I i I I 1 I 1 l I l l l I
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l ( ) Microfilm and store calculations in RIMS Service Center l l_04) Microfilm and return calculations to: &v m ': m.m Microfilm and destroy. () l ec: RIMS, SL 26 C-K O.G . A Eh/FR O Address: Wl0 A52 C-K '
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[ H. L. Jones, DNE DSC-A, SON Sheet I of 4 l
( C. R. 8rimer, ONE DSC-E, SQN R. C. Weir, Wl0 Cl26 C-K DNEl-37100 L_.
JUSTIFICATION FOR CONTINUED OPERATION WITH UNIHPLEMENTED REVISION LOG CORRECTIVE ACTIONS FOR MODERATE ENERGY LINE BREAKS SQN-SQS4-008@
""'"-" Date No. DESCRIPTION OF REVISION Approved 1
The cover sheet nd Section 2 were revised to change reference to unverified assumptions to assumptions.
These assumptions concerned corrective actions that will be addressed, tracked, and resolved in accordance with
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TVA's CAQ program pursuant to Significant Condition Report SQNNEB8617, R2 Section 5.2.1 was revised to reflect new information in CAQR SQP871291 that door C-14 between the turbine and control buildings is not watertight.
Attachment of S&L report 2SL-4424.
was revised to reflect the 3-6-87 revision Attachment 3 was revised to reflect R2 of SCR SQNNEB8617.
i went l Minor clarifications *us .made on several pages.
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TVA 10534 (EN DES 4 78) l
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Sheet 1 of 13 JUSTIFICATION FOR CONTINUCD OPERATION WITM UNIMPLEMENTED CORRECTIVE. ACTIONS FOR MODERATE ENERGY LINE BREAK FLOODING Prepared by/date M f-f4 Checked by/date f-/5 -D !
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1.0 Purpose and scope lAr/
The purpose of this safety evaluation is to provide a justification for continued operation (JCO) of both units with unimplemented corrective actions for moderate energy line break (MELB) flooding in (1) Mode 5 before restart and (2) in Modes 1 through 6,until startup for fuel cycle
- 5. The scope of this safety evaluation includes the corrective actions that are unique to MELB flooding. It does not include electrical itens related to resetting circuit b 3akers that'were developed in the flooding d?/
evaluation since several of these affect other events as well as flooding (see third paragraph in attachment 3) 2.0 Assumptions 2.1 Thecompleted be restart corrective for unit action items in Attachment 3 are assumed to 2 startup.
2.2 The post-restart corrective action items in Attachment 3 are assumed AP/
to be completed for both units before startup for fuel cycle 5 for either unit.
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2.3 The annulus drain sump alarm system (associated with LS-40-12A and-LS-40-12B) will be functionally tested as soon as is practical (no later than unit 2 startup).
i 3.0 General Safety Evaluation The MELB Event - MELB is a separate initiating event. As such, it is necessary to assure the capability to shutdown only for this event, i.e.,
it is not necessary to concurrently postulate other ' design basis events.
Accordingly, I loss of plant features which are required only for startup, operation, and mitigating of other DBEs is acceptable in terms of the plant's capability to achieve safe shutdown following a postulated MELB.
Floodinn Evaluation - Sargent and Lundy (S&L) has prepared a comprehensive safety evaluation of MELB flooding for SQN. The scope, design criteria for the evaluation, results, and recommendations for I corrective actions to achieve safe shutdown are defined in the S&L report SL-4424 (reference 7.1).
Attachment 1 (section 3 of SL-4424) summarizes the methodology, the major elements, and the individual calculations in the evaluation. As indicated in Sections 5.1 and 3.9 of project Instruction PI-SQ-05 ( Appendix A of SL-4424), the evaluation covers plant operating conditions during reactor startup, refueling, testing, operation at power, hot standby, or reactor cooldown to cold shutdown condition (i.e., Modes 1 through 6).
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- SQN-SQS4-0088 Shset 2 of 13 JUSTIFICATION FOR CONTINUED OPERATION WITH UNIMPLEMENTED CORRECTIVE ACTIONS Prepared by/date d M. _6 f
FOR MODERATE ENERGY LINE BREAK FLOODING j y-S&L Recommendations - Attachment 2 (Section 7 of SL-4424) indicates that the evaluation demonstrates the ability to achieve safe shutdown for postulated MELB flooding events provided that the recommendations listed are implemented.
Failure Evaluation - The failure evaluation in Revision 1 of the Engineering Report (reference 7.2) (designated as the ER hereafter) for SCR SQNNEB8617 evaluates the potential failure effects if the S&L recommendations are not implemented.
TVA Corrective Actions - Attachment 3 defines the set of corrective actions that remain to be implemented to address the S&L recommendations. The corrective actions are divided into (1) actions required for unit 2 restart and (2) post restart items. These corrective actions are the same as those in Attachment B of SCR SQNNEB8617 (R2) l4/
(reference 7.3) (designated as the SCR hereafter) and of the ER.
4.0 Justification for C,ontinued Operation in Mode 5 Until Unit 2 Restart Work is underway to address the corrective action items identified in Attachment 3 as being required before Unit 2 restart. The following discussion is a JC0 for units 1 and 2 in Mode 5 until these restart action items are implemented. The action item numbers correspond to the action item numbering in Attachment 3. Justifications are not given for action items where it is self evident that it is not needed. The l
following justifications are an extension of those provided in the evaluation in section 5 of this calculation.
The JC0 for unimplemented post restart action items is provided in section 5 of this calculation.
4.1 Turbine Building Flooding - Barrier Integrity - (Action Items -
l 1.1.1. 1.2.1 and 1.3.1) - The restart required activities associated with turbine building flooding are intended to assure that there are no major leakage paths into the control and auxiliary buildings.
The major source of turbine building flooding is a break in the CCW system. The CCW pumps are not in use for the majority time that l plant is in Mode 5. If the break did take place or if the system l was misaligned when the CCW pumps are not operating, flooding would I take place; however, it would be limited to elevation 683 - the l
' maximum normal river level. This should have no impact on the control and auxiliary building because the water must reach elevation 685 in the turbine building before it has access to any control or auxiliary building barriers.
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-- n SQN-SQS4-0088 Sheet 3 of 13 l
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JUSTIFICATION FOR CONTINUED OPERATION WITH UNIMPLEMENTED CORRECTIVE ACTIONS Prepared by/date k d M F-V-F 7 FOR MODERATE ENERGY LINE BREAK FLOODING y r
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The CCW pumps are only operated for short periods in Mode 5, and _
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usually only one pump is operated. The time margins for' detection i and isolation and the flood levels are bounded by those in section l
5.2.1 for the CCW in full operation. Breaks in other systems can !
produce turbine building flooding that might conf.inue to be pumped g/)
into the building. However, the flow rates for these breaks are .,
mur.h less than for the CCW breaks with the CCW in full operation. .;
Hence the time margins to reach the access to the control building l and auxiliary building barriers are rather long. The methods of l detecting turbine building flooding are discussed in section 5.2.1.
Sections 5.1 and 5.2.1 indicate the frequency of MELBs to be low. l 4/ l Thus, there is a low probability of a major turbine building flood-during the short exposure interval before the restart items are ;
completed.
Based on these factors, a MELB in the turbine building and subsequent flooding in the control or auxiliary building by transmission through the building barriers does not have significant probability of leading to inoperability of systems-required for safe shutdown in the interval before the restart action items are implemented. NEB considers this to be a sufficient JC0 for this interval.
4.2 Mnulus Flooding - (Action Item 1.5.1) - Section 5 gives a JC0 for continued operation after restart for.this item. This is based on !
implementation of action item 1.5.1. Section 5.1 indicates that the I frequency of MELBs is low. Thus, there is a low probability of a break in the annulus during the short exposure interval before the restart items in action item 1.5.1 are completed. The annulus drain sump alarm system (associated with LS.-40-12A and LS-40-12B) should be functionally tested as soon as is practical. With this tested, the probability of a pipe break and a failure in the annulus drain sump alarm during this interval does not_have significant probability of leading to inoperability of systems required for safe shutdown in the interval before the restart action items are implemented. NEB considers this to be a sufficient JC0 for this interval.
4.3 Flooding Electrical Equipment on Elevations 734 and 749 - (Action Item 1.2.2)- This action item has been implemented via QIR SQNEEB092 (B25 87026 031).
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'l SON-SQS4-0088 Sheet 4 of 13 JUSTIFICATION FOR CONTINUED OPERATION WITH UNIMpLEMENTED CORRECTIVE ACTIONS prepared by/date /d dkfd '7-1-d' ,
FOR MODERATE ENERGY LINE BREAK FLOODING " d Checked by/date k 7&T- y?
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5.0 Justification for Continued Operation in Modes 1 through 6 Until Startup f for Fuel Cycle _5 J The S&L evaluation has concluded that the components needed for safe ,
shutdown are not affected by the postulated MELB flooding events. I However, a few secondary, indirect,'or minor potential damage mechanisms remain to be addressed as post-restart corrective actions to substantiate or verify this conclusion. j l
The following subsections address (1) the probability of a MELB, potential for damage to safe shutdown equipment, risk to the public, and j (2) the individual remaining corrective actions that are related to these
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indirect or ninor potential damage mechanisms. i The ra'ionale t in the following subsections indicates that there is a reasonable assurance of achieving a safe shutdown following a MELB event until startup for cycle 5 without the implementation of the post-restart corrective action items. A MELB is a low probability event, and when coupled with the probability for any subsequent potential damage to the equipment needed for safe shutdown by these secondary, indirect, or minor damage mechanisms, the result is an even lower probability for system ,
inoperability. The following rationale is based on references 7.2, 7.4, I and 7.5.
The post-restart corrective action items do need to be implemented before startup for fuel cycle 5.
5.1 probability Of a MELB. DamaRe To Safe Shutdown Equipment, and Public Risk 5.1.1 Direct Submergence - The components needed for safe shutdown are not submerged by the MELB flood levels. These calculated levels were based on several rather conservative assumptions, such as (1) break flows of several hundred gal / min from critical crack size breaks, (2) no credit was taken for flow out through the floor drains, and (3) the break flow was allowed to continue for one hour before it was terminated.
On a realistic basis, the flood levels would be considerably lower.
5.1.2 Probability of a MELB and Damage to Safe Shutdown Equipment -
The frequency of the occurrence of a MELB is typically assumed to be about 10-3 per year. The likelihood of a MELB followed by subsequent damage to some of the safe shutdown equipment by the remaining open items should be about 10-4 to 10-5 per year. We have not evaluated these remaining open items fully; however, there is a reasonable probability they may not be sources of damage to safe-shutdown equipment. In addition, the flooding (vent would INEl - 3954Q
l' SQN-SQS4-0088 Sheet 5 of 13 JUSTIFICATION FOR CONTINUED OPERATION
. WITH UNIMPLEMENTED CORRECTIVE ACTIONS Prepared by/dateAU*rM 8M 9-#17 FOR MODERATE ENERGY LINE BREAK FLOODING Checked by/date F '
b 7-6 1 )
(f pl have to be in a specific location where one of these remaining items could affect some of the safe shutdown equipment. Thus, the probability of a MELB event which could affect some of the safe shutdown equipment before startup for fuel cycle 5, is low.
5.1.3 Risk to the Public - probabilistic Risk Assessments (PRAs) typically yield estimates of reactor core damage due to internal flooding of approximately 10-5 to 10-6 per year. Typical estimates of internal flooding which have an impact on public risk are approximately 10-8 or lower per year. This low probability for public health risk is due to the fact that a flooding event must satisfy a fairly large set of conditions in order for it to be significant. For example, (1) the flooding event must cause a plant condition which aould lead to core damage; (2) the event must be in a location which could result in failure of multiple trains of equipment of success paths (or must be such that it is combined with other independent failures of equipment);_(3) the severity of the flood must be sufficient to overwhelm drainage paths and actually flood the equipment; (4) the .
event must be such that it would not be detected via alarms- !
or by plant personnel; and (5) operator recovery actions must be precluded by the nature of the event. Thus, the risk to the public from a MELB event until startup for fuel cycle 5 is extremely low, i
5.2 post-Restart Corrective Action Items The action item numbers correspond to the action item numbering in !
Attachment 3. Justifications are not given for action items where !
it is self evident that it is not needed. I 5.2.1 Turbine Building Flooding - Barrier Integrity - (Action Items
- 1.1.1. 1.2.1. 1.3.1, 2.1.1, 2.2.1. 2.3.1. and 2.4.1) - Per TVA direction, the S&L study assumed that the turbine building wall would be sealed. A detailed analysis of flooding effects via leakage throurh the doors, hatches, penetrations etc., in the wall was not performed. Recent l 4rf efforts (i.e., C. R. Brimer's memorandum to H. G. O'Brien dated January 26 1987 (B25 870126 001), QIR SQP86128 (B25
' 861023 012), and the restart required activities associated with turbine building flooding are intended to assure that thete are no major leakage paths to the control and auxiliary buildings. One exception is that door C-14 between the turbine and control buildings is not water tight (see AE /
reference 7.6).
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," $QN-SQS4-0088 Sheet 6 of 13 JUSTIFICATION FOR CONTINUED OPERATION WITH UNIMPLEMENTED CORRECTIVE ACTIONS Prepared by/date J.48d fW-E FOR MODERATE ENERGY LINE BREAK FLOODING Checked by/date 7-N- T) '
/ V On a realistic basis, the doors, hatches, penetrations, etc., should not be exposed to very high' water levels, and thus, the leakage should be low. The turbine building-flooding must reach elevation 685 before it has access to any control or auxiliary' building barriers. There is a time margin of about 48 to 53 minutes before the largest flooding rates (from a failure in a CCW expansion joint bellows) reaches elevation 685. This allows sufficient time to detect and trip the CCW pumps or isolate breaks in other systems. (This CCW pump. trip approach is described in the FSAR section 10.4.5.3 and is the licensing basis.)- After the CCW pumps are stopped, the water level in the turbine-building will continue to rise due to gravity drainage from the discharge pond and the diffuser pond. The. level to which the water'will rise in the turbine building is dependent upon the operating mode (i.e., open, helper, or closed) of the condenser water cooling. In the open mode, the' flood level in the turbine building will rise to about elevation 687 in #
32 minutes after the CCW pumps are assumed to be tripped at l
elevation 685, and then it'will recede to elevation 685 in sf/
another 55 minutes. In the helper or closed modes, the flood level will rise to about elevation 686 in.16 minutes after i the CCW pump trip and recede to elevation 685 in another 6 minutes. ]
(This is based on the cooling tower lift pumps j continuing to to operate.) See details in reference 7.7.
The leakage for these flood levels is expected to be low for all of the doors, hatches, penetrations, etc., except for door C-14 As indicated above, the flood levels will be at elevation 687, or less, for about one and one-half hours. ,
The leakage for this door is estimated to be about 51. gal / min 1 for a flood elevation of 688 (see reference 7.8). Thus, the leakage'is within the capacity of about 95 gal / min of one of j
i the two sump pumps in the control building (see reference 7.9). The sump pumps have partial redundancy. They can be manually loaded on the diesels when they might-be needed in one hour or longer after a pipe break. Although these are 1 not safety-related pumps, they should be capable of providing reasonably reliable water removal.. Additional damage control measures, such as dewatering pumps, can be taken to accommodate the leakage.
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SQN-SQS4-0088 Sheet 7 of 13 h j
l JUSTIFICATION FOR CONTINUED OPERATION 4 WITH UNIMPLEMENTED CORRECTIVE ACTIONS Prepared by/date M .d.d M 9 4'P~/
FOR MODERATE ENERGY LINE BREAK FLOODING V Checked by/date & Yl %n- n ;
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There are several methods for detecting flooding in the turbine building: {
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1 (1) Level detection - Two existing alarm systems would alert the operator of the need to trip the CCW pumps '
or isolate other breaks to terminate turbine building ;
flooding before the time margins above are exceeded.
The two annunciator systems have partial redundancy with four level sensors, two annunciator windows, an uninterruptible power source with a battery backup, Although these are not safety-related alarms, 3
etc.
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they should be capable of providing reasonably l reliable notification to the operators for terminating turbine building flooding events before water reaches j significant levels.
j (2)
System detection - Flooding in the lower elevation of the turbine building will disturb the condensate and gj l feedwater cycle by flooding motors for hotwell pumps, condensate drain pumps, etc. The unit (s) would trip and several system alarms would annunciate for this equipment. An operator would normally be sent to I
investigate.
(3) Discovery by locci personnel - Operators and security personnel are located continuously in the turbine
' building. An assistant shift engineer is stationed in the turbine building, and a guard station is located near door C-14 at elevation 685 in the turbine building. These personnel would be able to detect a major break in the turbine building and suppicment the ;
detection in the control room.
The power supply to the CCW pumps are provided with redundant remote manual trip capability to allow the operator to trip the rising water in the condenser pit. Although these are not safety-related trips, they should be capable of providing reliable trip functions.
Industry experience suggests that expected failure rate for the CCW expansion joint is about 4.5 x 10-3 failures per l year. Thus, there is a low probability of a major turbine building flooding event during the short interim period which would exist between restart and completion of methods for dealing with any remaining leakage paths through the penetrations.
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SQN-SQS4-0088 Shsst 8 of13
, , :,., a s JUSTIFICATION FOR CONTINUED OPE 5f,T10h ' n Prepared by/date b M 8A8 d+1 f
- 7I WITH UNIMPLEMENTED CORRECTIVE ACTIOld 3 FOR MODERATE ENERGY LINE BREAK FLOODING \ >.N s $heckedby/date f* /.)A d M .s3 ,
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s1 The breaks in the bbW systet['are' limiting fee flooding in the I
,tdPoide building,.! Breaks'ih'other systems csn produce turbine building flodding thst(might' continue.to be pumped into the building. iK'owever, the<1: low rates for these breaks E/
', are much less than for the CCW4/ceaks with the CCW in full operation. Herive the margins W reach >the access to the control buildinj.and auxiliary building barriers are rather long-. ,
Based on these factors, an MELB in the turbine building and l h
subsequent flooding in'the control or auxiliary building by Transmission through the building barriers does not have
'significant probability of leading to.inoperability of cystems required for safe shutdown in the interval before the b
i podt-restart action items are implemented. NEB considers
% this to be a sufficient JC0 until startup for fuel cycle 5.
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5.2.2 Annulus Flooding - (Action Items 1.5.1.'2.1.3, and 2.2.5) -
The existing annulus dqain sump alarm system would alert the operator o& flooding I;n the ainiulus and the need to open the
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valve in the(drain linh to the auxiliary building passive
,. sump. This G 4 sindic track non-safety alarm (two sensors
, feeding *a singlehalarm); however, with routine surveillance,
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it should be capable of providing notification to the j l }
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\ oper. intors . The time margin to reach heights of water to suh'.erge IE diectrical equipment is about 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> (on the basis of flooding rates in the flood level calculation
'\ SQN-SQS4-056 (B45 87106 428) and equipment elevations in QIR NEB 87036 (B25 870130,063). This is the limiting time margin s since the informal judgment of CEB personnel is that the
's structural integrity 'will not' be threatened with 15 feet of f flooding. 3 3
With these provisions and the restart required activities, s nulus floodias does not have significant probability of ieading to inoperability of systems required for safe ishutdown in the intesval'before the post-restart action items
are implemented. NES, considers this to be a sufficient JC0 until startup for funi cycle 5.
5.2.3 Cable Subme3ggnee - faction Item 2.2.2) - Reference 7.5 i
frdicates that there is a reasonable assurance that any I t postulated submergence of these cables for a short period of I
t, t,ime.frucVa's onti to two days) will not result in any oeucada'.lon of the cables. This assurance is derived from
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3 N the fact that cable testing'is performed by cable
+ hapufactubers in accordance with Insulated Cable Engineers Association (ICE.A) standards. Thus, cable submergence in 4, y ,,
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j SQM-SQS4-0088 Shsot 9 of 13 JUSTIFICATION FOR CONTINUED OPERATION i i
WITH UNIMPLEMENTED CORRECTIVE ACTIONS prepared by/date M. #84$w 9M FOR HODERATE ENERGY LINE BREAK FLOODING k checked by/date N / y.g. O f
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plain water or borated water does not have significant l probability of leading to inoperability of systems required ]
for safe shutdown in the interval before the post-restart j action items are implemented. EEB considers this to be a l sufficient JC0 until startup for fuel cycle 5. '
S.2.5 Conduit Sealing - (Action Item 2.2.3) - Same as Cable Submergence above.
i 5.2.6 Conduit Acting As Water pipes - (Action Item 2.2.4) - The TVA review of S&L's study has raised the question of the acceptability of potential water leakage being routed via the l coruuits to essential equipment at other locations. Conduits I
mi6 ht function as water pipes if,there is significant inleakage from submerged (1) threaded connections, (2) l conduit body covers, or (3) equipment with conduit entries.
l At this time the significance of this concern is not known.
S&L did not consider this potential damage mechanism in their study. It is expected that there will be only very limited
' amounts of water routed via this mechanism. Although all sealants are not leak-proof during submergence, the inleakage and potential damage is restricted by the following: ,
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- 1. All spare conduits are plugged and sealed on both ends. l
- 2. Conduits between fire cells are generally sealed internally at the fire cell boundary. l
- 3. All conduits penetrating ABSCE boundary walls and floors and other pressure boundaries are already sealed internally.
- 4. Some areas have only conduits which enter / exit above flood levels and could not function as water pipes.
- 5. Some conduit fittings are being sealed for the HELB flood.
Accordingly, leakage rates should be small. Also, the total amount of inleakage should be small because the flood levels will drain below the majority of the conduit couplings, etc.,
within a few hours via flow through the normal drains. These two factors will provide relatively long time periods for operator action.
Based on these factors, this secondary, or indirect, potential damage mechanism does not have significant probability of leading to inoperability of systems required for safe shutdown in the interval before the post-restart action items are implemented. EEB and NEB consider this to be a sufficient JC0 until startup for fuel cycle 5.
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,' SQN'-SQS4-0088 Sheet 10 of 13
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JUSTIFICATION FOR CONTINUED OPERATION WITH UNIMPLEMENTED CORRECTIVE ACTIONS Prepared by/date b M 82 ble F-# 4'7 j FOR MODERATE ENERGY LINE BREAK FLOODING V Checked by/date Wh 7"P77 Y V 5.2.7 Evaluate Unintended (Spurious) Operations - (Action Item 2.4.2) - A large portion of the potential unintended (spurious) operations have already been addressed in two efforts. S&L included the equipment identified as " spurious l list" in calculation, " Equipment Required for Safe Shutdown per 10CFR50, Appendix R. "(NEB B25 860624 302) in the safe shutdown analysis SQN-SQS4-57 (B45 870106 427). Calculation, "Nonsafety-related Electric Equipment Process Interfaces Important to Safety per 10CFR50.49(b)(2) "SQN-OSG7-038 (B45 860721 218) demonstrated that the nonsafety-related process l interfaces do not create unacceptable unintended operations. !
Both of these efforts will need some extension to cover the !
remainder of the MELB situation.
The probability of this small extension of these existing -
efforts determining any significant adverse unintended -
(spurious) operations is low. Thus, unintended operations do 1 not have significant probability of leading to inoperability of systems required for safe shutdown in the interval before the post-restart action items are implemented. NEB considers this to be a sufficient JC0 until startup for fuel cycle 5.
5.2.8 Isolation valves with power Removed - (Action Item 2.4.3) -
Power has been removed from several valves identified in the system isolation calculation, SQN-SQS4-055 (B45 870106 426).
While it is possible to operate these valves using local manual action or by restoring power, these actions may extend the isolation time beyond that assumed in the analysis. For i the majority of the cases, this should not be a problem because the flood levels in 80 percent of the zones are-steady state. Thus, the assumption of detection and isolation within one hour is not critical. The concern in these cases is filling and-overflowing the passive sump.
There is at least a three hour time margin before this could damage safety equipment. See background in the flood level calculation, SQN-SQS4-56, pages 18, 19 A15, etc. Also, other means of isolating the specific pipe breaks are often available.
Thus, the power removal from the isolation valves does not have significant probability of leading to inoperability of systems required for safe shutdown in the interval before the post-restart action items are implemented. NEB considers i '
this to be a sufficient JC0 until startup for fuel cycle 5.
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, SQN-SQS4-0088 Sheet 11 of 13 !
JUSTIFICATION FOR CONTINUED OPERATION WITH UNIMpLEMENTED CORRECTIVE ACTIONS prepared by/date /d**t d 8 M oly % # 7 FOR MODERATE ENERGY LINE BREAK FLOODING V .I Checked by/date N h 7ac s>
r a i
i 5.2.9 Non-Seismic piping Evaluation - (Action Item 2.4.4) - The safe shutdown analysis calculation, SQN-SQS4-57, demonstrates that the MELB safe shutdown set of equipment is protected from flooding from breaks in non-seismic piping. This addresses the large majority of the safety concerns; however, it does not meet the regulatory guidance in RG 1.29 that includes the protection of the full Seismic Category I set of equipment. The MELB safe shutdown set of equipment does include the majority of the seismic Category I set of equipment. An earthquake is not considered to cause a LOCA, steam line break, etc., that would create the need for Seismic Category I equipment beyond the MELB Safe Shutdown j set. See R. W. Cantrell's memorandum to Those listed dated December 23, 1986 (B01 861222 001).
Thus, the lack of an evaluation of flooding effects on j Seismic Category I equipment beyond the MELB safe shutdown !
set does not have significant probability of leading to I
inoperability of systems required for safe shutdown in the {
interval before the post-restart action items are '
implemented. NEB considers this to be a sufficient JC0 until startup for fuel cycle 5.
5.2.10 Backflow Through Drains - (Action Item 2.4.5) - S&L and NEB have reviewed the drain design and layout, and based on this review, their judgment is that there is a high probability that this expanded evaluation will not increase the flood levels. The path of least resistance is down into the floor drain tank rather than back up through a floor drain. The larger piping systems (and flooding sources) are on the lower floors within the plant.Thus, the lack of this expanded evaluation of backflow through the drains does not have significant probability of leading to inoperability of systems required for safe shutdown in the interval before the post-restart items are implemented. NEB considers this to be a sufficient JC0 until startup for fuel cycle 5.
5.2.11 Safety Injection test Mode - (Action Item 2.5.1) - The exposure time when the SIS is in the test mode is very short. Thus, the probability of a SIS pipe break during these test intervals prior to startup for fuel cycle 5 is very low. When the SIS is in test mode there does not exist a significant probability of a pipe break leading to inoperability of systems required for safe shutdown in the
, interval before the post-restart action items are l implemented. NEB considerJ this to be a sufficient JC0 until startup for fuel cycle 5.
DNE1 - 3954Q
SQN-SQ54-0088 Shost 12 of 13 JUSTIFICATION FOR CONTINUED OpEFATION WITH UNIMPLEMENTED CORRECTIVE ACTIONS prepared by/date_ h .d # MAEiv 7*4 P7 FOR MODERATE ENERGY LINE BREAK FLOODING V checked by/date N d 4 7- e ry l
(/ V 5.2.12 Surveillance on Flood Alarms - (Action Item 2.5.2) - The flood alarm (detection) system are one of three general means of detecting pipe breaks. The other two means are (1) indication by system parameters in the system suffering the '
pipe break, and (2) discovery by roving operators or security personnel. Based on the availability of the other means of i detection, the lack of surveillance provisions does not have significant probability of leading to inoperability of systems required for safe shutdown in the interval before the post-restart action items are implemented. NEB considers this to be a sufficient JC0 until startup for fuel cycle 5.
l l 6.0 conclusions
' The comprehensive S&L evaluation has concluded that the components needed for safe shutdown are not affected by the postulated MELB flooding events. However, a few secondary, indirect, or minor potential damage mechanisms remain to be addressed as restart and post-restart corrective actions to substantiate or verify this conclusion. A MELB is a low probability event, and when coupled with the probability for any I subsequent potential damage to the equipment needed for safe shutdown by !
these secondary, indirect, or minor damage mechanisms, the result is an even lower probability for system inoperability.
This safety evaluation has shown that there is a reasonable assurance of achieving a safe shutdown following a MELB event (1) during operation in Mode 5 before the restart corrective actions are implemented, and (2) )
during operation in Modes 1 through 6 before the post-restart corrective actions are implemented. )
The restart corrective action items do need to be implemented before the j startup of unit 2. The post-restart corrective action items do need to be implemented before startup for fuel cycle 5 for either unit. l l4/
7.0 References !
7.1 NEB calculation, Moderate Energy Line Break Flooding Evaluation Report, gf SL-4424, SQN-SQS4-126 (B45 870521 426). ..
7.2 Engineering Report (R1) for SCR SQNNEB8617 (B25 870204 009) .
7.3 Significant Condition Report, SCR SQNNEB8617 (R2) (B25 870807 012)
(B25 870807 013). gf 7.4 D. W. Wilson's memorandum to SQEp Files dated December 12, 1986 (B25 861212 008)
DNEl - 3954Q !
I
',' $QN-SQS4-0088 Sheet 13 of 13 !
l JUSTIFICATION FOR CONTINUED OPERATION WITH UNIMPLEMENTED CORRECTIVE ACTIONS Prepared by/datekMdM 9-/5t7, FOR MODERATE ENERGY LINE BREAK FLOODING V 1 Checked by/date F/ 7-$- A7 0
1 {/
7.0 References (Continued) I I
~7. 5 D. W. Wilson's memorandum to DNE Files dated October 14, 1986 l (B25 861014 001). j 7.6 Condition Adverse to Quality Report CAQR SQP871291 (S13 870803 838). I 7.7 NEB calculation, Turbine Building Flooding Due to Breaks in the Condenser Circulating Water System, SQN-SQS4-0067 (B45 870915 426).
4T/.
7.8 MEB Calculation, Flow Leakage from Door C14. SQN-410-D053, EPM-JEI-082187 l (B25 870831 801).
l 1 7.9 MEB calculation, Control . Building Sump Pump Discharge to Turbine Building -
Flood to 690 ft., SQN-40-D053, EPM-RHM-082787 (B25 870828 109),
I i
J 1
DNE1 - 3954Q w_ _ _- - __ -
. , SA,RGENT & LUNDY
~
3-1
- 9. ' A 7~7McHMEN7* / SL-4424
.08-29-86 Rev.12-12-86 :
I Section 3 METHODOLOGY l
GENERAL i
The goal of this study is to demonstrate that safe plant shutdown can be achieve basis MELB flooding events. This requires both a structural load assessment and an elec ,)
equipment safe shutdown evaluatwn. These in turn require input on flood levels aris .
postulated MELB flooding events. The major elements of this study were Flood level calculations (including field verification of input parameters) I Structural load assessment I
Safe shutdown IE electrical evaluation (including field identification of submerged Class equipment) j
- (
Safe shutdown power supply analysis Cable submergence analysis Exhibit 3-1 shows the relationships among the tasks required to perform this overall evaluation.
These tasks are further described in a series of Sargent & Lundy Project Instructions, PI-SQ-04, -05, and -06.8,9,10 "MELB Flood Level Calculations"Il provides flood levels for postulated MELB flooding ;
events for input to structural flood load and safe shutdown assessments.
These calculations are summarized in Section 4.
" Structural Flood Load Assessment.12 verifies structural adequacy by comparing design basis
.MELB flood loads to allowable floor live loads provided by TVA and to concrete wall capacities calculated by Sargent & Lundy.
Section 5. This assessment is further described in I
4*M h * *'** *
]
SARGENTOLUNDY
,' -2 jt-424 l 08-29-86 {
Rev.12-12-81 :
C i
L The safe shutdown evaluation was divided into three parts.
Analysis"I3 "MELB Safe Shutdown examines safe shutdown for MELB flooding events in which Class 1E electrical equipment was found to be submerged based on field walkdowns.N This analysis assumes that safe shutdown power supplies and submerged cables that are required during the MELB flooding event. This is ensured by two analyses presented in Sec .
The design criteria used to perform the various evaluations of this study are co
- Sargent & Lundy Project instruction PI-SQ-05, " Evaluation of the Effec Inside and Outside Containment."9 This document is included as Appendix A to this report. -
Specific modeling calculations 11,12,13,15 assumptions used to perform various analyses are docume TVA INPUT DOCUMENTS .
A number letters, of TVA documents, including drawings, diagrams, calculations, des ,
memoranda, surveillance instructions, general operating instructions, system operating instructions, and reports, were used as input analyses. to the various MELB flooding Use of these documents is controlled by Sargent & Lundy Project Instruc PI-SQ-17, " Project Instruction for Use and Control of TVA Drawings and D Sequoyah Flooding Study."16 The TVA documents used by Sargent & Lundy are recorded on three separate document control logs, one each for EPED, NSLD, and SED.I7'I8'I9 in addition, cognizant technical personnel at TVA provided verbal direction an ,
which in turn were documented by Sargent & Lundy.
FIELD VERIFICATION Field verification of various input parameters used to calculate flood leve by the Sargent & Lundy walkdown team under Sargent & Lundy Pro 06.10 - -
MELB flood levels, under the same project instructi.on.T R I
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I SARGENT& LUNDY 7-I 4 7 7 4 C N M d N 7- )
2 SL-4424 .1 08-29-86 {
Rev.12-12-86 j Rev. 03-06-87 j Section 7 I
{
s CONCLUSIONS AND RECOMMENDATIONS The ability to achieve safe shutdown was demonstrated for postulated MELB flood.ng events provided the following recommendations are implemented:
/ -
TVA Test Procedure SL-129, "ECCS Injection Pump Operability,should be i
i revised to include the requirement for both Division A and Division B safety injection pump cubicle doors to be open during functional testing of either ,
pump. This is only required during surveillance testing of the safety injection pumps and not during plant-wide SI signal tests. This requirement ensures that design basis MELB flood loads in these cubicles are less than the allowable live loads provided by TVA.
2 -
The auxiliary building / turbine building and control building / turbine building wall should be flood protected to elevation 706 feet 0 inches.
.5 + HPFP lines in Zones 749.0-A6,749.0-A7, 749.0-A10, and 749.0-All should be !
shown to be equivalent to Seismic Category 1(L) Pressure Boundary Retention. This may require sprinkler head modifications. !
1- Conduit containing cables required for MELB safe shutdown that are located k below MELB flood levels should be sealed. Alternatively, the cables may be {
shown to be qualified for submergence. i j
l 5+ Conduit containing cables connected to safe shutdown power supplies that 1
are located below MELB flood levels in areas affected by borated water l should be sealed. Alternatively, the cables may be shown to be qualified for j submergence. '
C* Revise the protective device settings for the following main circuit breakers in accordance with the recommendations contained in Sargent & Lundy l Calculation No. SQN-EFS-001-1:
B_oard Breaker Location 480-V Shutdown Board lAl-A 480-V Shutdown Board 1 Al-A Cu0icle IB 480-V Shutdown Board IB1-B 480-V Shutdown Board IB1-B Cubicle la 480-V Shutdown Board 2Al-A R 480-V Shutdown Board 2Al-A Cubicle IB 480-V Shutdown Board 2B1-B 480-V Shutdown Board 2BI-B Cubicle IB
[
SARGENT 8 LUNDY 7-2 i SL-4424 08-29-86 Rev.12-12-86 Rev. 03-06-87 Board Breaker Lockation C&A Building Vent Board 1 Al-A 480-V Shutdown Board,l Al-A C&A Building Vent Board IB1-B 480-V Shutdown Board IB1-B C&A Building Vent Board 2Al-A 480-V Shutdown Board 2Al-A
~7 -
Verify the structural adequacy of walls and floors in Zones 669.0-A15,669.0-A 16, 714.0- A7, and 714.0-A8 for the flood levels provided in NSLD Calculation 3C37-0686-001, Revision 3.II F -
Flooding in the reactor building annulus must be limited to 2 : inches by providing free flow in the drain system or modification to the detection and isolation system.
l 9 + The test return header to the refueling water storage tank and certain component cooling system piping in Zones 714.0-A7 and 714.0-A8 are l
assumed to meet the crack exclusion criteria.
1
/0 - Spurious operation of associated equipment that might prevent safe shutdown I was not evaluated in this report. I
- l
// The effect of degraded bus voltage due to MELB flooding was not evaluated in this report. Sargent & Lundy recommends that TVA consider resetting the )
g !
auxiliary building supply fan breaker to reduce the degraded voltage duration. '
i PROGRAM FOLLOWUP I Sargent & Lundy recommends that TVA summarize implementation of the above recommen-dations through issuance of a TVA calculation "MELB Flooding-Summary of Corrective Actions."7 This calculation will document corrective actions taken by TVA to ensure that the intent of the Sargent & Lundy recommendations is met.
i 1
1
-se
ATTACHMENT 3 SEQUOYAH NUCLEAR PLANT MELB FLOODING - ACTION ITEMS The following corrective action items are the same as those in attachment B of A? /
SCR SQNNEB8617 (R2) (reference 7.3). The recommendation numbers following the action item titles correspond to those in Attachment 2.
After restart, EEB will determine which of the parallel efforts on conduit sealing / cable submergence in actions items 2.2.2 and 2.2.3 will be pursued.
"Jhe revision of the protective device settings per recommendations 6 and 11 is I a generic issue that is broader than MELB avents. This will be handled separately. The protective devices for C&A Building Vent Boards 1Al-A and 2Al-A are being addressed in SCR SQN EEB 86124 R0. The protective relays for the 480V shutdown board feeder breakers require resetting and will be handled ##
as a CAQ. The revision of the protective device settings for C&A Building Vent Board 1B1-B and the auxiliary building supply fan breakers are enhancements and do not involve an SCR or PIR.
- 1. ACTION ITEMS REQUIRED BEFORE UNIT 2 RESTART 1.1 Mechanical Discipline Action Items 1.1.1 Turbine Building Flooding - Barrier Integrity - (Recommendation 2)
Close the drain path from the turbine building to the control building as defined in J. C. Key's memorandum to V. A. Bianco dated Deceroer 17, 1986 (B25 861217 005) (reference ECN-L6827). Assure that the current sealing provisions of the doors potentially subjected to turbine building flooding meets the design (reference #II worL request (WR) B221027 to replace the seals on doors on elevation 685).
1.2 Elec".rical Discipline Action Items 1.2.1 Turbine Building Flooding - Barrier Integrity - (Recommendation 2) -
Seal conduit PL 3057 in accordance with existing drawing requirements as defined in C. R. Brimer's memorandum to H. G. O'Brien dated January 26, 1987 (425 870126 001) i(reference WR B277234 and V. A. Dianco's menorandum to C. R. Brimer dated July 24, 1987 4?/
(B25 870724 016)!.
1.2.2 Floodiur. rP etrical Equipment on Elevations 734 and 749 - Expand the evaluation in Q1R SQN EEB85003 (U25 850701 002) to verify that the electrical equipment in all of the electrical boards on elevations 734 and 749 are above the MELB flood levels defined in the floud level calculation SQN-SQS4-056 (B45 870106 428). This action item has been completed via QIR SQNEEB092 (B25 870216 031). gy f DNE4 - 39 iQ NEB 8/87 I
i
, .SEQUOYAH NUCLEAR PLANT MELB FLOODING Sh:r,t 2 ef 5 ACTION ITEMS 1.3 Civil Discipline - Action Ttems 1.3.1 Turbine Building Flooding - Barrier Integrity - (Recommendation 2) -
Assure that existing sealing of turbine building to control building hatch cover at El. 685 is restored to design condition (reference WR B208207).
1.4 Nuclear Discipline Action Items 1.4.1 Review of Unimplemented ECNs - Update the previous review of unimplemented ECNs to determine if subsequent ECNs impact the flooding evaluation. This action item has been completed via D. G. Renfro's memorandum to H. G. O'Brien dated June 25, 1987 d?/
(BAS 870625 259).
1.5 Plant Manager's Office Action Items 1.5.1 Annulus Flooding - 1) recommendation 8) - Develop an instruction to provide operating surveillance of the annulus drain sump alarm system l (associated with LS-40-12A and LS-40-12B). Develop provisions for '
inspection of the annulus for flooding if the alarm system is inoperable. Kevise system operation instructions SOI-55-1H15 (page
- 7) and S01-55-2M15 (page 7) to add an action to open valve 77-920 to jpj drain the annulus cump to the auxiliary building passive sump (reference CATS No. 87043 and WR B211257, 258, 259, and 260). The time margins for inspection if the system is inoperable and to open i valve 77-920 is about 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />. These provisions may be discontinued upon completion of action item 2.1.3.
- 2. POST RESTART ACTION ITEMS 2.1 Mechanical Discipline Action Items 2.1.1 Turbine Building Flooding - Barrier Integrity - (Recommenda. tion 2)
Implement improved sealing of mechanical penetrations in control and !
auxiliary building boundaries as defined in part of ECN L6790, and J. I C. Key's memorandum to SQEP Files dated October 1, 1986 (B25 861001 064). Improve the discharge path and capabilities of the control building sump pumps for turbine building flooding conditions. Add a sump pump (if required) to the south mechanical equipment room, elevation 669 in the turbine building (reference ECN L6827). Provide l AC/
the information on the barrier leakage during turbine building flooding as requested in QIR NEB 86244 (B45 861126 252). Obte.in supporting information as needed.
DNE4 - 3961Q NEB 8/87 I
I
1 l
SEQUOYAH NUCLEAR PLANT MELB FLOODING Shsst 3 of 5 ACTION ITEMS l
2.1.2 HPFP Seismic {; Lj:apability - (Recommendation 3) - Document that the HPFP lines in .e9aJ 749.0 -A6, -A7, -A10, and -All will not have a loss-of-pressure 14undary in an earthquake. The HPFP modifications related to these zones as defined in ECN L6770 and J. C. Key's l memorandum to SQEP Files dated October 1, 1986 (B25 861001 064), are field completed.
2.1.3 Annulus Flooding - (Recommendation 8) - Develop methods of providing free flow in drain system similar to WBN. (A possible alternative if this approach is not practical is to upgrade the flood alarm system -
see action item 2.2.5).
2.2 Electrical Discipline Action Items 2.2.1 Turbine Building Flooding - Barrier Integrity - (Recommendation 2) -
Perform the electrical penetration sealant modification for the i
conduits entering the control / auxiliary building fecm the south !
mechanical equipment room elevation 669 in the turbine building as defined in ECN-L6828. Document the adequacy of electrical penetrations for turbine building flooding to elevation 706 for the
" passive" approach and quantify any estimated leakage. (Reference
- Wyle Test Reports No. 17833-01 and -02.)
2.2.2 Cable Submergence - (Recommendations 4 and 5) - Develop an engineering justification that cables will operate satisfactorily under MELB submergence conditions. See inputs from reference 5, S&L (B45 860905 218), SQN EQP, and WBN EQP. Document the justification. l This is an alternative to action item 2.2.3. l 2.2.3 Conduit Sealing - (Recommendations 4 and 5) - Seal the conduits for (1) cables required for MELB safe shutdown which are located below ,
the MELD flood levels and (2) cables connected to safe shutdown power i
supplies that are located in areas affected by borated water. This should be combined to the degree practical with the conduit sealing for the flooding from high energy line breaks (HELB) to resolve SCR SQN EQP8621. EQP has conducted testing of conduit couplings for MELB conditions and the additional field inspections, or verifications, to identify the conduits below MELB flood levels. EED has conducted more formal testing of the conduit coupling and condulet sealing (see Wyle Test Reports No. 17833-01 and -02). If there are large number of conduits involved, it may be cost effective for NEB to arrange for S&L assistance in reducing the set below the size of the (1) S&L safe shutdown set of August 12, 1986, and (2) set of cables connected to safe shutdown power supplies that are located in areas affected by borated water. If problem areas arise where the flood depth or duration exceeds the MELD conduit coupling test conditions, (such as in the UHI zone), NEB can assist in developing alternate approaches (such as curbs, door modifications, etc.). Document the adequacy of the conduit sealing.
i
! This is an alternative to action item 2.2.2 (see reference 5). Consideration should be given to an alternative resolution of sealing all conduits below the MELB and HELB flood /2 /
levels. This would also resolve action item 2.2.4.
DNE4 - 3961Q NEB 8/87
k SEQUOYAH NUCLEAR PLANT MELB FLOODING Shast 4 of 5.
ACTION' ITEMS 2.2.4 conduits Acting as Water Pipes - Evaluate the TVA concern'on the acceptability of water, which may-leak through fittings on flooded conduits, being routed via the conduit to essential equipment at other locations. These conduits are being sealed or rerouted for the HELB effort. S&L did not consider this failure mechanism in their study. Seal the conduits if needed. See the alternative resolution jg/~
-in action item 2.2.3 Document the resolution of this concern. j 2.2.5 Annulus Flooding - (Reconnendation 8) - Upgrade the annulus drain i sump alarm system if required. See action item 2.1.3. 1 l
2.3 Civil Discipline - Action Items 2.3.1 Turbine Building Flooding - Barrier Integrity - (Recommendation 2) -
Provide the information on the barrier leakage during turbine i building flooding as requested in QIR NEB 86242.(B45 861126 253). 1 2.4 Nuclear Discipline Action Items _
l l 2.4.1 Turbine ~ Building Flooding - (Recommendation 1) - Evaluate estimated .i l inleakages through the control and auxiliary building boundaries to- 1 determine if these are within the design capability of the sump and l sump pumps. Develop additional methods of handling the inleakage if j needed.
2.4.2 . Evaluate Unintended (Spurious) Operations - (Recommendation 10) -
Evaluate unintended operation per section 5.5 of Project Instruction )
PI-SQ-5 in reference 1.
i 2.4.3 Isolation Valves with power Removed - Develop methods of addressing the use of motor operated valves with power removed for isolation of pipe breaks in a timely manner. See punch list item 1 in the system isolation calculation, SQN-SQS4-055 (B45 870106'426).
2.4.4 Non-Seismic Piping Evaluation - The analysis in section 6.4 (page l' 25), and Appendix B of the safe shutdown analysis calculation, SQN-SQS4-057 (B45 870106 427), needs to be expanded from the MELB safe shutdown set of equipment to the full set of Seismic Category I .;
equipment per section 7.1 of the project instruction PI-SQ-5 in !
reference 1.
2.4.5 Backflow Through Drains - The treatment of backflow from higher floors through drains into lower floors in Appendix H in the flood i level calculation, SQN-SQS4-056-(B45 870106 428) will be expanded per item 1 in the punch list for this calculation. .
2.4.6 Revision of MELB Calculations - The calculations will be revised to address the punch list items and the unverified assumptions. The more significant items and assumptions are' listed as separate action items in this listing. The use of any non-QA inputs such as telecons will be upgraded to QIRs if needed.
DNE4 - 3961Q NEB 8/87 ,
=' SEQUOYAH NUCLEAR PLANT MELB FLOODING Shast 5 of 5
. ACTION ITEMS 2.4.7 Addition of Flood Levels to Environmental Drawings - Add the MELB flood levels to environmental data drawing series 47E235.
l 2.4.8 Input to operations - Provida input to the plant manager's office for !
their use for either (1) procedures, (2) training, and/or (3) l de/
background. This will be design output (or functional information I output). I 2.4.9 Summary of Corrective Actions - Document the final corrective actions in a calculation that is referenced in the summary report as indicated in Attachment A. -
2.4.10 Licensing Documentation - Revise FSAR Section 3.6 to reference {
flooding study in next FSAR revision. It has been determined that a separate submittal to NRC is not needed.
2.4.11 Unreinforced Masonry Block Walls - Develop and implement a design change to eliminate the block walls from the Seal. Water Injection Filter Valve Roons (El 690, All-T and AS-T). The desibn change should satisfy both flooding and ALARA concerns. Although the 4/
drawings reflect the existence of the walls, the walls have been removed and it is understood they will not be replaced. The MELB flooding evaluation assumed that these walls had been deleted.
i 2.5 Plant Manager's Office Action Items I 1
Safety Injection Test Mode - (Recommendation 1) - Revise test 1
2.5.1 procedure per recommendation 1 in Attachment A (reference CATS No. l 4/ i 87-100).
2.5.2 Surveihance on Flood Alarms - Develop a procedure for surveidance testing of the turbine, auxiliary, and reactor building flood alarm (detection) system (reference drawings 45W650 and 45N655-27), turbine ;
building station sump level alarm (LS-40-1B), control building floor '
and equipment sump level alarm (LS-40-2B), ERCW pumping station mechanical equipment room sump level alarm (1-LS-40-72D, 1-LS-40-73D, 2-LS-40-72D, and 2-LS-40-73D), and ERCW pumping station deck sump jgr level alarm (LS-40-81D and L:S-40-82D). Note that section 6.3.2.11 of the FSAR includes a commitment for periodic testing of the flood detectors in the auxiliary building that are used to detect ECCS leakage following a LOCA (reference H. D. Elkins memo to B. M.
Patterson dated February 25, 1987, (S53 870225 984)). These detectors are a subset of those flood alarm systems above.
l DNE4 - 3961Q NEB 8/87
i I
ENCLOSURE 2 Corrective Action Status All restart action items identified in SCR SQN NEB 8617 required for unit 2 restart are complete with exception of item 1.2.1, Turbine Building Flood Barrier Integrity. This item will be completed by October 30, 1987.
postrestart action items identified in SCR SQN NEB 8617 will be administrative 1y controlled and implemented after restart.
The unimplemented portion of item 1.2.1 involves the sealing of door C-14, the auxiliary instrument room fire door on elevation 685. The proposed method for sealing this door is to use neoprene seals. This method represents a deviation from a previous commitment to use Underwriters Laboratory (UL; listed material on fire doors. This door is the primary pathway between the !
Turbine Building and Control Building. The neoprene seals were evaluated to be the only material suitable for this high traffic door. The neoprene seal is not UL listed material. The TVA calculation included as an attachment j documents the evaluation of the use of neoprene seal of door C-14. TVA l concluded that the proposed modification will not degrade the fire endurance capability of the door assembly,
)
(
l 1
4 ATTACHMENT to ENCLOSURE 2 SQN-00-D052 EVALUATION OF NEOPRENE SEAL i F,0IFICATION ON DOOR C-14 l
l l
l l
TVA 10697 (DNE 646) DNE CALCULATIONS SHEET 1 0F 7 TITLE PLANT / UNIT EVALUATION OF NEOPRENE SEAL MODIFICATION ON DOOR C-14 ,
SQN UNITS 1 and 2 PREPARING ORGANIZATION KEY NOUNS (Consult RIMS DESCRIPTORS LIST)
MEB FSG FIRE DOORS, ELEV 685. AUX INSTRUMENT ROOM BR ANCH/ PROJECT IDE NTIFIE RS Each time these calculations are tssued, preparers must ensure that the original (RO) RIMS access on number is f ailed on.
SQN-00-D052 Rev (for RIMS' use) RIMS accession number
~"
EPM-EAC-091087 B44 '87 0 916 0 0 5 APPLICABLE DESIGN DOCUMENT (S)
R DCN 47A (B25870831511) g_
SAR SECTION(S) UNID SYSTE M(5)
R _,,,
Revision 0 R1 R2 R3 Safety related? No G Yes O ECN No. (or indicate Not Appbcable)
NM Statement of Problem Prepared In order to seal the Aux M
- 1) The door remains in the opening during the fire endurance test and the hose stream test.
- 2) The movement of swinging doors shall not result in any portion of the edges adjacent'to the door frame moving from the original position in a direction perpendicular to tMe' plane of the door more than the thickness of the door during the first half of the classification period, nor more than 1-1/2 times the door thickness during the entire classification period or as a result of the hose stream test.
- 9) The test assembly shall have withstood the fire endurance test and hose stream test, without developing openings anywhere through the assembly, except that small portions of glass dislodged by the hose stream shall not be considered a weakness.
- 5) No flaming shall occur on the unexposed surface of a door assembly during the first 30 minutes of the classification period. After 30 minutes some intermittent light flames (less l than B inches long).for periods not exceeding r, minute intervals l may occur along the edges cf doors. Light f1r. ming may occur during the last 15 minutes of the classification period on the unexposed surface area of the door, provided it is contained within a distance of 1-1/2 inches from a vertical door edge and within 3 inches from the top edge of the door and within 3 inches from the tcp edge of the frams of a vision panel.
- 7) Door frames to be evaluated with doors shall remain securely fastened to the wall on all sides and shall not permit through openings between frame and doors or between frame and adjacent
- wall.
- 1) Material used in the. construction of the frame and door leaf.
- 2) Type of latching mechanism.
- 3) Structural integrity of the door assembly.
- 1. The moderate energy line break modification to the neoprene seal on door C-14 will be completed by October 30, 1987 1