ML20012B331
| ML20012B331 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 03/06/1990 |
| From: | Rosa F Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| TAC-68510, TAC-68511, NUDOCS 9003140205 | |
| Download: ML20012B331 (15) | |
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UNITED STATES 1
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MAR 61990 l
' Docket Nos.:
50-334 50-412
-BeaverVa$leyUnits1and2 I
ORGANIZATION:
Duquesne Li ht Company (DLCo)
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SUBJECT:
MEETING
SUMMARY
- MEETING OF FEBRUARY STATION BLACK 0UT ISSUES (TACS 68510/6851122,)1990,ON x
Reference:
Meeting Notice by P. S. Tam dated February 7,1990.
I The subject meeting was held as specified in the referenced notice. Enclosure l
1 is a list of meeting attendees, and Enclosure 2 is the agenda proposed by the licensee. The licensee provided a draf t document entitled " Alternate AC Load Management Scheme for Beaver Valley"; copies of that document were available to attendees,and a copy is included as Enclosure 3.
The guidance on the use of existing emergency diesel generators (EDGs) as alternate ac (AAC) power sources is documented in RG 1.155 Position C.3.3.5 and NUMARCB7-00Section2.3.1(3). This' guidance is further explained in NUMARC 87-00 Supplemental Questions and Answers dated December 27, 1989, under questions 3.4.and B.3.
The staff interpretation of this guidance was presented by Mr. Ashok Thadani, Director of Systems Technology, NRR in his opening remarks in this meeting. Mr. Thadani stated that the station blackout (SBO) rule in-cludes a very explicit statement regarding the use of.EDGs as AAC at multiunit sites.. Mr. Thadani read the rule statement:
"At multi-unit sites, where the combination of emergency ac power sources exceeds the minimum redundancy require-
.ments for safe shutdown (non-DBA) of all units, the remaining emergency ac power sources may be used as alternate-ac power sources provided they meet the applicable criteria."
Mr. Thadani explained that this statement requires minimum redundancy. This-
.means that in order to qualify as an AAC source, there must be an EDG available in the non-blackout (NBO) unit that is in addition to the number of EDGs re-quired to meet the minimum EDG redundancy requirement for powering a normal safe shutdown for a loss of offsite power (LOOP) event. Thus, the EDG's in a two unit site with two dedicated EDGs per unit would not qualify as AAC sources because the two EDGs per unit just meet the minimum redundancy requirement, i.e., there is no excess EDGL.
However, there are some plants at two unit sites which just meet minimum re-dundancy but where each EDG is of sufficient capacity to fully power all the normal LOOP loads of the-NB0 unit, and also has sufficient excess capacity for powering the required safe shutdown loads of the SB0 unit.
In recogni-tion of the existence of this type of situation, the staff has relaxed the literal excess EDG redundancy requirement of the SB0 rule to allow these EDGs to qualify as AAC sources, provided other applicable requirements are also met.
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Meeting Summary 2
h The following points were made to clarify the guidance for use of EDGs as AAC sources at multi-unit sites:
1.
The basic philosophy should be that no action should be.
taken that would exacerbate the already difficult situa-tion in the NB0 unit.
2.
The excess capacity of the EDG being designated.as an AAC source should not be the capacity made available by shedding or not powering normal safe shutdown loads in the NB0 unit.
Examples of such loads are motor driven AFW pumps, HVAC loads, the power supply of the plant computer, and one or more sets of. redundant instrumentation. The shedding of such loads con-i stitutes degradation of the normal safe shutdown capability of the hB0 unit.
3.
Any actions that make operator tasks more difficult, such as load switching or disablement of information reacouts or alarms in the control room, are considered to be a degrada-tion of normal safe shutdown capability for LOOP in the NB0 unit.
The Beaver Valley approach for using a Unit 1 EDG as an AAC source for an SB0 in Unit 2 was described by the licensee. The Unit 1 EDGs (2850kW, 2000 Hrs) do not meet the above cited excess capacity criteria for qualification as AAC sources. The staff conclusion was that conformance with the SB0 rule for an e
SB0 in Unit 2 must first be demonstrated by using the coping analyses approach,
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but that operation of a Unit 1 EDG as described by the licensee during an SB0 in Unit 2 could be included in the-Emergency Operating Procedures as a con-tingency measure..It was noted that this issue was not applicable to the case of an SB0 in' Unit 1 because the Unit 2 EDGs (4532kW, 2000 Hrs) have the required excess capacity tu qualify as AAC sources.
The meeting ended with the understanoing that the Beaver Valley licensee would submit a revised SB0 response to the NRC by March 30, 1990.
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Faust Rosa, Chief Electrical Systems Branch Division of Systems Technology L
Enclosure:
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'0FFICIAL RECORD COPY l:
Document Name:
F. ROSA
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-4 Docket Files SELB Rdg(..-PF)(2)
-1 P. Gill J. E. Knight-F.: Rosa-NRC PDR Local PDR PDI-4 File T. Murley J. Sniezek J. Partlow
- S. Varga' C. Boger
'C. Haughney OGC
-E. Joroan B._ Grimes-P. Tam (13)
F. Miraglia A.' Thadani l-J; Raval C. McCracken R. Architzel J. Wermiel i
l W. F. Kane, RI
-M. W. Hodges, RI l-1.,
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- Mr.: J. SieberL Beaver Valley Power Station g.
Duquesne Light' Company Units 1 & 2 I
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- l JahE.-Silberg, Esquire Bureau of Radiation Protection 3
Shaw, Pittman, Potts and Trowbridge Pennsylvania Department of 2300 N Street, N.W.
Environmental Resources Washington, DC 20037 ATTN:
R. Janati' Post Office Box 2063 i
Kenny Grada, Manager Harrisburg, Pennsylvania 17120 Nuclear Safety.
Duquesne Light Company.
Mayor of the Borrough of P. O. Box <4 Shippingport Shippingport.2 Pennsylvania 15077 Post Office Box 3 Shippingport, Pennsylvania 15077 John A. Lee, Esquire Ashley C.-Schannauer Duquesne Light Company-Assistant City Solicitor One Oxford Centre City.of Pittsburgh-301 Grant Street-313 City-County Building Pittsburgh, Pennsylvania 15279 Pittsburgh, Pennsylvania 15219 p
Commissioner Roy M. Smith Regional Administrator, Region I West Virginia Department of Labor U.S. Nuclear Regulatory Commission Building 3, Room 319 475 Allendale Road i
Capitol Complex King of Prussia, Pennsylvania 19406 L
Charleston, WV 25305 John.D. Borrows Resident Inspector-E Director,-Utilities Department U.S. Nuclear Regulatory Commission Public Utilities Commission Post Office Box 181 180 East Broad Street Shippingport, Pennsylvania 15077 Columbus, Ohio 43266-0573 Director, Pennsylvania Emergency i
L Management Agency l
Post Office Box 3321 Harrisburg, Pennsylvania 17105-3321 I'
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_ ENCLOSURE 1-h (,
_ ATTENDEE-LI ST pa h
-MEETING WITH DUQUESNE LIGE COMPANY ON STATION BLACKOUT I SSUES, 2/22/90 -
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AGENDA NRC EETING WITH DUQUESNE LIGHT COMPANY (DLCO)
Thursday, February 22, 1990.
ALTERNATE AC LOAD MANAGEMENT SCEME A STATION BLACK 0UT ISSUE I.
Introduction John Maracek/NRC staff
.II.
DLCO's Understanding of Original Station Blackout Regulatory Requirements and Subsequent Clarifications John Maracek III.
Proposed Safe Shutdown Leads for Beaver Valley Unit 1 Ron Zabowski I V..
Safe Shutdown Loads Assumed by Remainder of Industry Vittorio Pareto V.
Proposed changes to Licensing Basis Emergency Loads
- John Maracek VI.
Discussion VII. NRC Staff Cau'cus (if needed)
VIII.. Concluding Remarks NRC Staff
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. Alternate AC Load Management Scheme For Beaver Valley
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Introduction During the February 3,1990 station t.'ackout phone audit of Beaver Valley (BVPS), several i
questions were asked relating to the adequacy of the station's load management scheme. Th discussion responds to these questions and clarifles the loss of off site power (LOOP) )
. shutdown methodology. In our opinloo, this methodology is consistent with the requ the stadoc blackout rule (10 CPR 50.63), Regulatory Oulde 1.155, NUMARC 87-00, an{
recently lasued Supplemental Questions and Answers dated December 27,1989.
. Beaver Yalley is a two unit site utilizing an EAC source available from the non blacked (NBO) at un Altemate AC. The system meets the Altsrnate AC Criteria discussed in A NUMARC 87 00, and in our view,is capable of supplying the necessary safe shutdown lo both units. Since t.ie Unit 2 diesels are considerably larger, a substantial amount of exc Alternate AC pow 6r is available to cope with a blackout in Unit 1. For this mason, this di focures on the more limiting scenario where the excess capacity from the Unit I AAC power forUnit 2.
The maximum ac power mquirements needed during a loss of off site power am shown i 8.51 of station's FSAR. The Unit 1 proposed safe shutdown methodology during a LO concurant with a staton blackout in Unit 2, is 3enerally consistent with the PSAR discussio the most part, all systems indicated in the PSAR table are expected to be available bl:ckout of the adjacent unit. However, some of the systems listed in the table can by ac independent components, (ii) do not have a safety function during a loss of o or (iii) are am not generally powend within the expected duration of the station blackout. T unit's safe shutdown capability is not in any way degraded by employing this shutdown methodolory. In addidon, the flexibility normally available to the operators is not expe any way constrained.
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,j Al%rsett AC Lead Manage 2ast sehene For Beaver Volley February 30, 1990
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he sections below describe the proposed load management scheme in detail highlighting any differences hem the load list shown in the PSAR. Drve time periods are discussed: (i) the first hour, (ii) the following three hours, and (iii) an extended duration beyond four hours. It is impottant to understand that AAC power only needs to be available during the second period (item (ii)),
This proposed load management scheme is consistent with the additional guidance provided by NL* MARC on December 28,19901 (emphasis added):
The AAC source must carsy: (1) the loss of off site pour safe shutdown loodt on the non. blacked out (NBC) unit as described sn QlA answer 3.4, above and (2) the
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station blackout loads on the blacked out unit for the required coping duration. The capacity of the EAC soume of the NBO unit to be credited as an AAC source for the blacked out unit can only be the excess capacity above the loss of off site power loads of the NBO unit. Shedding of any loads should not icad to the degradation of the NBO unit's loss of off site power safe shutdown capability. Beyond the l
duration ofSBO the NBO unit should retain the cqpability to sqport its loss of of sitepowersafe shutdown loads.
Criterion B.9 of NUMARC 87 00 states,"[t]he AAC power system shall be sland to carry the required shutdown loadsfor the required coping duration determined in.
l Section 3.2.5 and be capable of maintaining voltage and frequency within limits consistent wlth the established industry standards, that will not degrade the L
performance of any shutdown systems or components. At a multi unit site, except for 1/2 shared or 2/3 emergency AC power configurations an adjacent unit's class IE power source may be used as an AAC powar source for the blacked out unit if it is capable of powerms the required loads at both units.
The method for determining the loss of off site power safe shutdown loads discussed in Question 3.4is as follows (emphasis added):
From NUMARC 87 00page 315:
The number of necessary EAC standby power sources should be determined by accounting of the individual sqfe shutdown loads or Mstzedfrom the site's design basis for operating Class IE equipment without off. site power.
1 Lener fmm Alex Marion, NUMARC, to Ashok Thadant, Attachment 1: NUMARC B7 00 Supple Questions /Answen, Question B. 3, daisd December 28,1989.
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Alternate AC Load Management Scheme For Beever VaBey February 30, 1990 i
w This determination does not need to take into consideration a simultaneous design
. basis event (other than loss of off site power). Furthermore, any variations (from i
the design bat'S) in the assumptions for loss of off site power loads should be t
identified in SBO responses to NRC and fully justified with documentation available.
Additionally shutdown loadt powered must be capable ofmaintaining the plant in a sqfe condition for an extended period (i.e. longer than the required coping duranon).
1 The loss of off site power load management scheme is summarized in Table 1 and illustrated in Figun 1. This loading is sufficient to maintain the NBO unit in a safe shutdown condition for an.
extended duration all beyond four houn. Beyond the duration of the SBO, the NB0 unit will retain the capability to support its loss of off site power safe shutdown loads. The AAC power system is adequately sized to carry the mquired shut down loads for the required coping duration maintaining voltage and frequency within limits consistent with the established industry i
p standards. Also, the loading arrangement will not degrade the performance of any shut down systems or components.
8000 pu how n
Capaany8080 kW
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000 etaihow 1 to 4 howe
- ter 4 hows Duration Figure it Alternate AC Load Management Scheme For Beaver Valley 3
Alternate AC Lead Me:eyment sehene For Seaver Vaney February 20, 1990
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Table 1: Alternate AC Load Management Scheme For Beaver Vauey
,. - y UNIT 1 UNIT 2 COMPONDT' LOADS (kW).
LCADS (RW)
NBC Unit 80 Unit aemerke o to I hourto Aher 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> to I hour 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> 4 hours d h.,-u'Ch Charging. Ha Head safety 442.0 442.0 442.0 4P7 k.0 )
Infection Pumn l
. River Water Pump 335,0 Hl.0 H I.0 Cress.te RW5 sisam Genernier AFW 302.0
'IDAFWP TDAFWP 5ee Section e Puse Primary Plant 221.0 221.0 221.0 Component Coolias Water Pume 4
Turbme meertag Dil Ltft 13.0 0.0 0.0 Ese Secuae d Pume Motor Oberated VaJves 5.0 00 0.0 See secuen c Emergency DAtel 21, 0.0 25.0 28,0 Austliartes A-Turbine Generator 39.0 0.0 0.0 5ee Escuen d '
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. Bearina Lube CX1 Pune y-Turbine TM Deer 39.0 0.0 39.0 Drive
- fressur.zer Hesisri 0.0 216.0 216.0 One hour delev
.or.c Acid "ransfer Pums 13.0
- 3.0 13.0 See 5ection e oric Acad "atk Heaters 1 $.0
- 5.0 15.0 at'.ery Charmers -
38.0 L
.0 3,.0 14.6 i-
) mergency Lighting 3.0
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- <.0 Sunelerneetal Emergency Lighdag 35.0
- 35.0 35.0
,Bunnlemental
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Coolainaset Air 253.0 0.0 0.0 5ee section.b.1 tectreulation Pana Gontrol Room Air 45.0 45.0 45.0 t
lueoly Pam Control Roca Air Return 25.0 25.0 25.0
_ Pens Control Room AC 61.0 61.0 61.0 27.4 Comoressors Control Room AC 4.0 4.0 4.0 Coederser CirosPtig Punes i:
L4ak Collocuon Exhaust
!!5.0 115.0 115.0
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,infeduards Atta Bump 4.0 4.0 4.0 Puteo Tmergency 5*F 4 5.0 9.0 5.0 Battery Room r.nhaust
'an-Imergency Swgr 4 13.0 13.0 13.0 aattery Room Supply
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'sel Pool Coo 11on Pumn 0.0 0.0 20.0 5ee section c 9 S M it w e n.* J I.
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UNIT 1 UNIT 3 COMPONENT -
LOADS (kW)
LOADS (kW)
NBC Unit 90 Ustt Remarke j
D2 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> lo After 1 hout m I hour 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> 4 hours a boun Control Rod Coohng
.81.0 51.0 81.0 36.0 goe 1 Jane
.dieesllaneous Pans, 13.0 13.0 13.0 3ammen and P-
- 4!a**:lassous Pans, 10.0 10.0 10.0 l
r Deenen. and Pumoa T
hoe Jest ' hema li ).O 0.0 1,0.1)-
5ee Secuen 6.4 6
hoe
- est 'Thetea i " ).D 0.0 i,0.0 See Recuon b 4 Vital 114: La e 4.0 30.0
.0.i)
Visce aneous 3
.0 62.0 1 2, )
I saters i 2 i
h intel anseus ' ' estern 0
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7.mergency AC
,,.0
.,1,0 11.1)
Distribution Passis Emegency AC 22.0 22.0 23.0-Dtatrbution Penals -
Contamaant lastr. Air 17.0 0.0 0.0 5ee Besuas t.2 Comoressor
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Comeuter Invarier 17.0 0.0 17.0 Bee Secuen b.3 45 Volt Battery Chi--
5.0 5.0 5.0 i
'i Additional 550 _
loads for 30 talt t
'^^d & Cochas System 49.0
_ Losses AC Die. Transf.
AC :hst. ' Tant'.
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AC lis t. rena '.
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5.1 Vita E us tact.
5.5 Vital Bus 'tect. 21 14.0 B'"*'y Room Bithaust -
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_AC Distr. Amt 2.9 AC Disir. amt q
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'0"A,LOAls 3565.9 1898.0 2094.0 666.8 m
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' Diesel generator 163 hour0.00189 days <br />0.0453 hours <br />2.695106e-4 weeks <br />6.20215e-5 months <br /> capacity a 2950 kW.
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A single CRDM shroud fan is sumelent during the first four hours for upper head cooling per EOPs and engineering evaluation Reference EM No. 22241.
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L *}.L Alternate AC Lead Managenoot Sehe3e For leaver VaBey February 10, 1990-Loads Available During The First Hour During the first hour of the event all applicable loads identified in the PSAR table may be powered.
This includes all loads that are automatically loaded onto the diesel generators. However, it is
. important to note that some loads are not normally energized until after a considerable delay. For example, as indicated in Table's.51 of the PSAR, spent fuel pool cochng is normally activated only after a two day delay. Por this reason, even though sufficient capacity exists, station procedures do not direct operators to activate pool cooling systems during the first four hours without off alte power.
i Loads' Avallable After One Hour and Before Four Hours l
After the first hour, a degree of load management is necessary to ensure adequate Altemate AC L
power is available for the blacked out unit. These loads fall into three cat:3ories: (a) 1oads that can L
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be displaced by ac independent components,- (b) loads that are not required to ensure safe shutdown capability, (c)1oads that are not generally powered within the expected duration of the station blackout, and (d) loads that do not have a safety function.
- s. Y ^* that enn be dhnhead hv an ac hhAmt - ----g Both Beaver Valley Units are equipped with 100% capacity turbine driven AFWpeqps. This capability can be used to displace the redundant motor driven APW pump that loads j
automatically onto the safeguard bus. Shedding this load does not in any way impair or degrade the NBO unit's safe shutdown capability._ Also, this does not preclude the operator from adding this load if the turbine driven pump becomes unavailabic. The motor driven pump is not disabled in any way. However, as discussed in the Supplementa1 Questiona/ Answers,1 station blackout single fa!!ure considerations, for multi unit sites where EAC sources are utilized for AAC power to an adjacent unit, are limited to one of the EAC sources in the NBO unit. No additional random failures need to be contemplated. Thus, for the purposes of calculating the available AAC power, the turbine driven pump may be assumed to be operable.
I Letter from Alex Marion, NUMARC, to Ashok Thadant, Attachment 1: NUMARC 87 00 Supplemental Quesdans/ Answers, Question B.1. dated December 28.1989.
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'Mternate AC Lead Manage 2ent Schere For Bester Vaney.
February to,1990 b. wa tu' = nt* maulmd to ma== ante ihnMawn chev
^ Several loads am not needed for normal safe shutdown following a loss of off site power.
nese include the containment air recirculation fans, the containment instrument air
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comressors, the comuter inverter, and heat tracing for the borated noter piping. The p
unavailability of these systems during thl period will not reduce the information available to L
the operators to monitor the safety related conditions of the plant, nor will it impair or damage the NBO unitin any way.
1 b.1 Containment cooling water is not safety r:1sted at Beaver Valley. Thus, the containment recirculation fans would not serve their cooling function and would only add to the heat generation. This condition has been analyzed and verified during plant operation.1 Containment tes, stures have been shown to not increase beyond 110'P during the fhst four hours of the event. This temperature is considerably below the EQ operability limit of 135' F.
L b.2 Similarly, cooling water for the containment instmment air compressor is not safety related, and consequentially is normally unavailable during a loss of off site power. For this reason, the compressor should be disabled since operation without cooling results in electrical trip of the component. Existing plant procedures for coping with a LOOP event direct operators to disable the compressor for a loss of cooling water resulting from the loss of off site power.
His systemin not required to ensure safe shutdown capability.
In an emergency situation, river water could be aligned with the containment cooling coils to i
pmvide cooling for the recirculation fans and instrument air compressor. However, this would likely impair the long term reliability of the coils, and would only be considered as a last resort, b.3 The station process computer, only serves as an additional source cf information and is not needed for responding to accident conditions. Existing Emergency Operating Procedurss (EOPs) do not rely on the information provided by the computer for achieving a safe shutdown condition.
1 LER 84 07 Loss of Containment Cooling 7
l [,r Ahorsese AC 146d Managemed Sebene Per Beaver Vater Febrcary 28, 1990 b.4 Heat tracing for the borated water piping is not required for over a bours.1 This is documented la the stadon's current technical specificadon. An SER was issued accepting this condition on September 16,1989, p, f mat that ama nat manavallv enwannd within the eraarted duradan af the atadam Waetrant It is important so tv>te that some safe shutdown loads ars only normally nooded during the first hour of the transient, or ecosiderably aher four hours. These loads include mesor operered velves, and the spent)%elpool cooling rystem.
Power for rsotor operated valves, will only be needed during the first ten minutes to realign safety systems. Since these cospnsnts are not normally energlied ther the first hour of the event they do not need to be powered aher the first hour.
The spent fuel pool cooling pumps e.n11 aot need to be powered until aher the soping parted for a loss of off site power. Thus,it is not necessary to consider this load during the four hour duradon of a stadon blackout.
d. ImAn that do nnt have a aafety funetlan.
ne turbine generster bearing tube ou pump, and the turbine bearing ou lift pump are used after turbine coastdown (appmalmataly thirty minutes). However, these are non safety related loads and are not required for the safe shutdown of the plant. The turbine turning gear drive, which is used to prevent turbine shaft warpage, is also not required for safe shutdown. The turning gear wul not be availabis unless diesel generator 1 is g 4 Loads AvaDable After Four Hours De stadon blackout rule only requires Alternate AC power to be pmvided for the station's required coping duration. hus, after four hours Unit 1 no longer needs to supply AAC power so Unit 2.
However, as discussed above, the proposed loading arrangement is sufficient to maintain the stadon in a safe condidon for an extended duration well beyond four hours. Thus, the only load that wullikely need so be added during this period is spent fusi pool cooling.
I DCL letar so ibe NRC, dated Jane 29,1983 (NDI $!,,C:0641). Raf. Technical Speci.tation Chase Request No.79.
2 ERR dated Sepesmber 16,19s3 tua the NRC rotative to Technical Specification Amendment No.71 8
Summary and Conclualon j
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%e load management scheme discussed above ensures the NBO unit is brought to and maintained in a safe situtdown condidon for an extended period well beyond four boun. No component is permanently disabled or in any way degraded. In fact, much of the load management needed is I
precisely to ensure long term operability of equipment. Por these reasons it is out opinion that this anangement mass all salsting SBo segulatory requirements.
Finally, it is our undantanding that every other utility in the United States with a similar diesel generator configuration (i.e. two unit site with 1/2 dedicated diesels) has made similar assumptions. Over 26 power plants constituting almost one quarter of the industry are proposing similarload manassment schemes.
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