ML20217Q860
| ML20217Q860 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 08/27/1997 |
| From: | Hughey W ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| PROJECT-689, RTR-NUREG-1465 GNRO:97-00075, GNRO:97-75, NUDOCS 9709030413 | |
| Download: ML20217Q860 (10) | |
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W.K.Hupey yy w,a rwm August 27,1997 U.S. Nuclear Regulatory Commission Mail Stop P1137 Washington, D.C. 2 % 55-0001 Attention:
Document Control Desk
Subject:
Submittal of Grand Gulf Nuclear Station Control Room Air Intake and Meteorological Information for the Rebaselining Study for Application of NUREG 1465 Source Terms:
Project No. 689 I
GNRO:
07/00075 Gentlemen:
This submittal completes the Grand Gulf Nuclear Station (GGNS) response to 4
Nuclear Regulatory Commission (NRC) requested information from the March 27, 1997 meeting between the NRC staff and GGNS staff.
In support of the BWR rebaselining effort, the NRC staff requested the control room air intake locations, distances from DBA release points, and directions in order to determine the GGNS control room x/Q values. In addition, the Staff requested five years of hourly meteorological data.
bdib Meteorological Data in a previous submittal dated May 14,1997, GGNS provided hourly meteoro!cgical data for 1995 and 1996. The enciosed diskette provides GGNS meteorological data for 1992,1993, and 1994. The format of this data is identical to that data previously transmitted.
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j Release Point Distances and Directions provides the control building intake points, and their distances and directions from the DBA release points. Section 1 of this attachment explicitly documents the GGNS release points and the applicable accident release phase during which source terms may be released from this point. Section 2 documents 7 m N'
the GGNS control building air intake locations. Section 3 reports the distances and
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directions from each release point to these intakes.
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GNRO 97/00075 Page 2 of 2 Again, we look forward to continued participation in this important project. If you have any questions concerning this submittal, lease Contact Tom Williamson at 601437 24g8.
Yours truly, W
/tiw attachment:
i ec:
Ms. S. C. Black (NRC/NRR)
Ms. K. Cozens (NEI)
Ms. J. L. Dixon Herrity, GGNS Senior Resident (w/a)
Mr. L J. Smith (Wise Carter) (w/a)
Mr. N. S. Reynolds (w/a)
Mr. H. L. Thomas (w/o) c Mr. E. W. Merschoff (w/a)
Regional Administrator.
U.S. Nuclear Regulatory Commission i
Region IV-611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011 i
Mr. J. N. Donohew, Project Manager (w/2)
Office of Nuclear Reactor Regulation -
U.S. Nuclear Regulatory Commission Mail Stop 13H3 Washington, D.C. 205S5 1
Y 0 97841'
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Att:chment i to GNRO 97000'/5 Pag)1 ref 8 1.0 Release Points The spectrum of GGNL radiological events was reviewed to identify the various appl'. cable release points for each ovent. These release points and the applicable accident release phases are reported in Table 1 Table 1 GONS Accidents and Release Points Accident Release Point Release Phase Loss of Coolant /
Secondary containment seepage during secondary containment drawdown Main Steam Line Containment ventilation vent before system isolation l
Break inside Cont.
Standby Gas Treatment System primary airborne release pati (SGTS) vent Tghine Building vent MSIVleakage befo_re LCS3eration FuelHandling SGTS vent drops with secondary conla'nment Containment ventilation vent drops in containment before system isolation Control Rod Drop Turbine Building vent primary airborne release r,ath l
Recire Pump Turbine Building vent primary airborne release path Selzure (SLO)-
Main Steam Lhe Main Steam Tunnel blowout panels primary altborne release path Break Outsidt; Cont.
The five release points that may be considered in the GONS control room dose anslysis are thercibre:
SOTS vent, cantainment ventilntion vent, e
l t.econdary containment seepage (exact release point to be specified later),
turbine building vent, and main steam tunnel blowout panel, e
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0 97841
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' to GNRO 9700075 Page 2 of 8 2.0 Con..".1 Room lutake Locations As discussed in GONS USAR Section 9.4.1.3, the control room IIVAC intakes are automatically isolated in the event of(i) high radiation in the outside air intake duct, (ii) high drywell pressure, i
or (iii) low low reactor water level. On these bases, the GGNS radiological analyses assume complete control room isolation before any source tenns can enter the control room via the normal ;ntilation pathway.
For a period of time, the control room will remain isolated with the control room fresh air supply system operating in the recirculation mode. During this time, the Safeguard Switchgear and Battery Room Ventilation (SSURV) system will continue to supply fresh air to the control building (outside the control room envelope) as part of its post accident safety function. As described in USAR Section 9.4.5.2, this air flow is provided by supply fans that would continue to operate under accident conditions with two of the four supply fans. These supply fans take suction from intake louvers located on lilevation 134' (ground level) on the west side of the control building. liventually, outside fresh air will be supplied to the control room through these same intake louvers and will be filtered through the Control Room Fresh Air Supply (CRFA) filter trains.
These intakes represent a significant flow of air into the control building. As reported in USAR Table 9,4 7, each of the two supply fans draws 21,000 cfm of outside air into the building. As the major cource of outside air into the control building, the distances and directions from all release points to the nearest intake are evaluated.
The current control room yjQ values re based on wind tunnel tests which concluded that the highest coefficients occurred at the roof of the control building Consistent with these tests, the distances from each release point to the control building roof were also evaluated. These distances may also be approviate in cases where the SSBRV system is unavailable such as station blackout. Considering me access door on the roof of the control building and the adjacent intake louver for the non safety elevator machine room 1500-cfm exhaust fan, the distances and directions to the intake louver of the elevator machine room exhaust fan were also calculated.
The GGNS dose analyses assume the control building source term concentration is identical to the concer.tration existing at this intake loemion. No dilution, transport delays, or removal mechanisms are credited in the control building. This atmosphere is then assumed to leak into the control room envelope.
G97841
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Attachment i to GNRO-9700075 Pace 3 of 8 p
3.0 Distances and Directions From Release Points This section addresses each release point and presents an illustration r. -he rcl case path from this
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point to the control building intakes, The distances and directions frot.: each release point to the intakes are reported in Table 2, 4.1 Standby Gas Treatment System Vent
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The SOTS systems release on the southwest corner of the Auxiliury lluilding. The two SGTS L
trains have difTerent vents that are located in close proximity to euch other. The distance 'iom the nearest SGTS vent was evaluated. The plant layout for this release is illustrated in Figure 1.
Control Building 21
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1 57,p b Enclosure Building Q-
~~yi True Auxiliary Building
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Figure 1 SGTS Release Point G97841
Att chment i to GNRO-9700075 Pag 3 4 of 8 i
4.2 Containment l'entilation System l'ent The containment ventilation system releases on the norti.s in corner of the Auxiliary Building.
The plant layout for this release is illustrated in Figure 2.
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Control Building rMVal0f MadlN m.
El 214' i
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SSBRyintakes El 134' g.
Enclosure Building
,4 True Norm Auxiliary Building Figure 2 Containment Ventilation Release Point J
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G97841
Attachment i to GNRO 9700075 l
Pago 5 of 8 4.3 Secondary Containment Seepage in the event secondary containment is not completely established, a sufficient vacuum may not exist to prevent direct leakage from the secondary containment to the atmosphere. This situation would exists, for example, during the two-minute secondary containment drawdown. During power operation, Technical Specifications require that secondary containment be maintained.
Seepage would not onginate from open doors or louvers since these openings would represent violations of secondary containment but from areas of the building boundary that may be more susceptible to leakage, Consistent with previous NRC correspondence (AECM-84/0051, Treatment of Containment Leakage hnmediately Following the Design Basis Accident, dated February 2,1984), the metal siding of the enclosure building is considered much more likely to leak than the concrete walls of the Auxiliary Building. Therefore, the distance and direction from the nearest portion of the enclosure building to the control room intake locations was evaluated. The plant layout for this release is illustrated in Figure 3.
Control Building Elevakr Machme Roomlouver El. 214'
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we-SS8RV Intakes EL 134
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Enclosure Buiiding True Norb Auxiliary Building Figure 3 Selos re Building Seepage Reloase Point G97841
Att chrnent i to GNRO-9700075 Pig 3 6 of 0 4.4 Turbine Building l'ent The turbine building ventilation system releases on the southwest corner of the Turbine Building.
The plant layout for this release is illustrated in Figure 4.
Turbine Building Control Building L
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,g, Enclosure Building in e
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Auxiliary Building Figure 4 Turbine Building Release Point I
G97841
Att: chm:nt 1 to GNRO 9700075 Pags7at8 4.5 Main Stearn Tunnel Blowout Panel The main steam blowout panel releases on the castern side of the Auxiliary lluilding. The plant layout for this release is illustrated in Figure 5.
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Control Building 0 214 L
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=M, Enclosure Building 2C J
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Auxiliary Building Figure 5 Main Steam Tunnel Blowout Panel Release Point t
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,4 1 Att:chment i to GNRO-9700075 -
Pag 2 8 of 8
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Table 2 Distances to Control Building Intakes TO SSBRV INTAKES-Release Point Distance to Controi Oldg Direction to Control Intakes (ft)
Bldg Intakes (True)-
SGTS vent 307.00 E
Containment ventiiation vent 145.09 NNW Secondary containment seepage 74.55 NNE Turbine building vent 329.55 N
Main steam tunnel blowout panel 163.70-N TO CONTROL BUILDING ROOF Release Point Distance to Control Bldg Direction to Control -
i Intakes (ft)
Bido intakes (True)
SGTS vent 286.85 ENE Containment ventilation vent 145.10 N-Secondary containment seepage 87.96
-NNE-Turbine building vent --
329.95 N
Main steam tunnelblowout panel 170.02 N
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