ML20059M425
| ML20059M425 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 09/24/1990 |
| From: | James Fisicaro ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 0CAN09908, CAN9908, NUDOCS 9010040170 | |
| Download: ML20059M425 (8) | |
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Rve 3 Eex 137G Operations nes ua mm Tet W %s3w0 September 24, 1990 BCAN09'.'08 -
-U. S. Nuclear Regulatory Commission Document Contrcl Desk Mail Station F1-137 Washington, DC 20555
SUBJECT:
Arkansas Nuclear One - Units 1 and 2 Docket Nos. 50-313 and 50 368 i
License Nos. DPR-51 and NPF-6 I
Station Blackout-Supplemental Information Gentlemen:
In our letter of July 17, 1990 (OCAN'079006), we, advised you that further of the ANO loading scheme for the proposed Crosstie Alternate AC (AAC) system was necessary.
In addition, we noted that-the revised loading 1
assumptions could potentially impact our analysis of the effects of loss of IIVAC and selection of Dominant Areas of Concern.
Itaving completed j
this effort, we wish to apprise you of clarifications and/or. revisions l
to our previous submittals in the following areas:
1)
/,AC Loading 1
2)
Loss of Ventilation 3)
Reactor Coolant Inventory
)
4)
Schedule These topics are discussed in detail for ANO-1 in Attachment l' and for l
ANO-2 in Attachment 2.
i We believe this submittal addresses your concerns discussed in a phone-call and completea our response to 10CFR50.63.
If you have any questions regarding this submittal, please contact my office.
Very truly yours, 0
.h James
. Fisicaro Manager, Licensing JJF:DEJ:fc I
Attachments j
g 9010040170 900924 D
.T PDR.ADOCK 05000313 Il p'-
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U. S. NRC Paga 2 September 24, 1990 cc:
Mr. Robert Martin U. S. Nuclear RegLlatory Commiscion Region IV-611 Ryan Plaza Drive, Suite 1000 Arlington, TX 76011 L
Mr. Thomas W. Alexion 3
l-NRR Project Manager, Region IV/ANO-1 U. S.. Nuclear Regulatory Commission NRR Mail Stop 11 B One White-Flint North 11555 Rockville Pike Rockville,-Maryland 20852 i
NRC Sr.r.ior Resident Inspector r
Arkansaw Nuclear One - ANO-1 & 2 i
Number 1, Nuclear Plant Road Russellville, AR 72801 L
l Mr. Chester Poslusny; I
NRR Project Manager,' Region IV/ANO-2 U. S. Nuclear Regulatory Commission.
NRR Mail Stop 11-B-19 i
One White Flint North 11555 Rockville Pike j
Rockville, Maryland 20852 L
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ATTACHNENT 1 Clarifications / Revisions To Previous Submittals'In Response To-10CFR50.63 (Station Blackout Rulel Arkansas Nuclear One Unit 1 (OCAN099008)
Reference Previous Submittals:
1) 1CAN048908, dated April 13, 1989
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- 2) 0CAN049004, dated April 3,-1990 3)
JAN079006, dated July 17, 1990 Following are additional clarifications and/or revisions to our previous submittals:
1.
A1_ ternate AC (AAC) Loading ANO han -re-analyzed the emergency diesel generator (EDG) loading for the proposed Crosstle AAC system (see attached Figure 1) in accordance with the NRC staff position presented in Hr. Faust.
Rosa's letter to NUMARC dated April 27, 1990.
In determining the total EDG loads for the~Crosstle AAC, the minimum required shutdown loads for the station blackout (SBO) unit were added to the Loss of Offsite Power (LOOP) loads for the non-blackout (NBO) unit. -Eight cases were reviewed, such that any of the fourEDGs'(2 per unit) could be used to supply AAC power to either of the SB0 unit's 1
emergency buses. The loading for the NB0 unit was. based on that unit's' license basis for LOOP.
These loads were considered to be identical to the LOOP loads listed in the ANO EDO loading-calculation (i.e., all " normal" LOOP loads), with the following clarifications:
a)
The NB0 unit loading does not include the; motor driven-l Emergency i'eedwater Putg after the~first. hour of.the event, since the enveloping single failure assumption is the. loss of i
one EDG and additional failures (e.g. failure of turbine driven EFW pump) are beyond the license basis 'of the NB0 unit.
If the failure of the turbine driven-EFW pump is postulated to be the design basis single failure, then both.EDGs are assumed operable and the motor. dr.iven EFW pump will he driven from its-t EDG.
b)
The NB0 unit loading.does:not include a Decay llent Pump, since -
the rule assumes both units'have been~at 100% power for 100 days, and the units will therefore be physically and procedurally limited to emergency feedwater-(secondary cooling) as the decay heat removal mode during the four hour event.
l 1
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2.
Loss of Ventilation In general, HVAC is assumed to be available to all needed areas in the NB0 unit (i.e., no load shedding of Emergency HVAC is credited or assumed.) For the case of an ANO-1 SBO, the following.
clarifications apply:
a)
Primary Maheup Pump Rooms This room was identified in a prior submittal as a Dominant Area of Concern (DAC).
However, per item 3 below, the ANO-1 program now assumes no makeup is necessary for the four hour event.
Therefore, HVAC will-not be provided, b). Service = Water Pump Structure This room was identified in a prior submittal as a DAC.-
It was subsequently determined that a loss of ventilation in' this area is not a concern for ANO-1 SBO, since service water is not needed for the four hour event.
Therefore, HVAC will not j
be provided.
c)
Control Room The ANO-1 Control Room will-not lose ventilation-for ANO-1 SBO.
The entire Control Room (both Unit-1 and Unit-2: sides)
W will continue to be cooled by either 2VUC27A-1 or 2VUC27B-2, powered br an ANO-2 EDG.
i 3.
Reactor Coolant Inventory i
The baseline assumption of NUMARC 87-00 that no RCS makeup.is required by PWRs for a four hour SB0 has been' adopted for ANO-1.
In addition to the generic analyses listed in Section'2.5.2 of NUMARC 87-00, Babcock & Wilcox (B&W); analyses-performed in support of the coping strategy developed by the Bebcock & Wilcox.0wners Group (B&WOG) Operator Support-Committee has shown that the core will remain covered for this event, assuming 100 gpm RCP seal-leakage and Technical Specification allowable' leakage.1 4.
Schedule 1q The modifications and associated procedure changes identified in.
our previous submittals are now planned to be-completed by the end of our refueling outage 2R9, currently estimated as November 6,:
1992, depending on actual date of 1R10 and 2R9 outagen and on the regulatory assessment to be provided by the Director, Office of Nuclear Reactor Regulation in accordance with 10CFR50.63(c)(3).
1-2
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ATTACHMENT 2 Clarifications / Revisions To Previous Submittals In Response To 10CFR50.63 (Station Blackout Rnle)-
Arkansas Nuclear One Unit 2 (OCAN099008)
Reference Previous Submittals:
- 1) 2 CARS 48904. dated April 13,:1989
-2) OCAN049004, dated Apr11'3, 1990
- 3) GCAN079006, dated July 17, 1990 4
. Following are additional clarifications and/or revisions'to our
.f submittals:
1.
Alternate AC (AAC) Loading ANO hcs re-analyzed the emerg6ncy diesel-generator (EDG) loading
(
for the proposed Crosstle AAC system (see attached Figure'1) in accordance with the NRC staff position presented in Mr.. Faust Rosa's letter to NUMARC dated April 27, 1990.
In determining the' total EDG loads for the Crosstie AAC, the minimum required shutdown.
Ioads for the station blackout-(SBO) unit were added to the Loss of--
Offsite Power (LOOP) loads for the non-blackout (NBO) unit. Eight; cases were reviewed, such that any of the four EDGs (2 per unit) could be used to supply AAC power to either of the.SBO unit's emergency buses. The loading for the NB0 unit was based on'that unit's license basis for LOOP.
These loads were considered to be 3dentical to the LOOP loads listed in the ANO EDG loading.
calculation (i.e., all " normal" LOOP loads), with. the following clarifications:
a)
The NB0 unit loading does not include:the motor driven Emegency Feedwater Pump after the first hour of the-event,-
s since the enveloping single failure assumption is'the loss of one EDG and additional failures (c'.g.,-failure of turbine driven EFW pump) are beyond.the license'basie iof the NB0 unit.
If the failure of the turbine driven EFW pump is postulated to 4
be the design basis single failure, then both EDGs are assumed operable and the motor driven EFW pump will be driven from :lts u
l EDG.
b)
The NB0 unit loading does not include a Shutdown Cooling' Pump (LPSI), since the rule assumes both units have been at-100%
power for 100 days, and the units wil11therefore be physically s
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and procedurally limited to emergency feedwater (secondary cooling) as the decay heat removal mode during the four hour event.
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2.
Loss of Ventilation In general, HVAC is assumed to be available to all needed areas in the NB0 unit. (1.e., no load shedding of Emergency HVAC is credited or assumed). For the case of an ANO-2 SBO, the following clarification applies:
l a)
Control Room 8
In the event of an ANO-2 SBO, the entire Control Room (both-ANO-1 and ANO-2 sides) will be cooled by either of. Emergency Unit Coolers 2VUC27A-1 or 2VUC27B-1, (normally supplied from Unit 2 safety buses), thich'will be powered by an ANO-1 EDG I
via the Crosstie AAC afs;r the first hour of the event.
sDuring the first hour-, the Unit 1 Control Room will be_ cooled-by existing unit cooler VUC-9 the door between the Contr71 Rooms will be opened and Unit 2 control cabinet doors will be opened or removed.. The ANO-1 Control Room air conditioner unit VUC-9 has sufficient capacity to remove Unit'l' Control Room heat-loads and provide.a heat sink'for Unit 2 Control-Room heat loads with the door between Control Rooms open.
~
Using NUMARC 87-00 methodology, an oisessment of Unit 2 Control Room temperature was performed for the above described circumstances.
The Control Rooms are considered to be-initially at 84'F (ANO-2 Technical Specification t
4.7.6.1.1.a.2) and no credit is taken for space above the dropped ceiling.
The result of.the assessment indicates that Unit 2 Control-Room temperature will not exceed'120'F.
i l
Subsequent to the first hour, either 2VUC27A-1 or_2VUC27B-2 will be adequate to cool the entire Control Room complex.
l 3.
Reactor Coolant Inventory 4
For an ANO-2 SBO, ANO. plans to y ver one ChargingiPump (44 gpm capacity) via the Crosstle AAC after the first hour of the event.
As stated in our previous submittal', the generic analyses' listed in Section 2.5.2 of NUMARC 87-00 can be_used in assessing adequate l
Unit 2 core cooling for L51s event, since'the analysos are-
[
applicable to typical Combu tion Engineering (CE) PWRs.
The NUMARC
^!
87-00 baseline assumption inc'uded' 100 gpm loss of _ inventory (25 gpm per pump) with no RCS makeup for the four hourfevent, and-
. concludes no core ur.covery will t cur. ( Therefore,- provision of a.
single Charging Pump after the fir.t hour of an ANO-2 SB0 is' considered to be conservative with respect to the NUMARC baseline assumuption.
6 2-2
I 4.
Schedule The modifications and associated procedure changes identified in our previous submittals are now planned to be completed by the end of our refueling outage 2R9, currently estimated as November 6, 1992, depending on actual date of.1R10-and.2R9 outages and on the-:
regulatory assessment to be provided by the Director, Office of 4
Nuclear Reactor Regulation in accordance with 10CFR50.63(c)(3).
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