ML20064A651

Suppls 871015 Application for Amends to Licenses NPF-9 & NPF-17,revising Requirement to Obtain 0.25 Inches Water Gage Negative Pressure in Auxiliary Bldg ECCS Pump Rooms in Tech Spec 3/4.7.7,per 900827 Telcon

ML20064A651
Person / Time
Site:	Mcguire, McGuire
Issue date:	09/04/1990
From:	Tucker H DUKE POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20064A652	List: ML20064A651 ML20064A653
References
NUDOCS 9009170210
Download: ML20064A651 (9)

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• DukeIbuer C:mpa:y HM B kw

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V . PO Bat 33198 ike President ,

Charlotte, N C 28342 Nuclear Production (Tol)3734531 i

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l DUKEPOWER September 4, 1990 j i U.S. Nuclear Regulatory Commission ATTN: Document Control Desk .

l Washington, D.C. 20555 O i

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Subject:

McGuire Nuclear Station, Units 1 and 2 I Docket Nos. 50-369, and 50-370 . .

Supplement to Proposed Amendment.to Technical Specification  ;

L 3/4.7.7, Auxiliary Building Filtered Exhaust Ventilation System '

! i Pursuant to 10 CFR 50.90, find attached a supplement to the proposed i amendment transmitted by my letter dated October 15, 1987, and supplemented , ,

by letters dated' Hay 11, June 1, and October 8, 1989. The purpose of this- ,1 supplement.'as discussed in a telephone conference on August 27, 1990  ;

by T.L. McConnell, Manager of McGuire Nuclear Station and D.B. Matthews, e Directorate 11-3 Director and their respective staffs, is to revise the j

-requirement.to obtain 0.25 inchea wate. gage negative pressure in the

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Auxiliary Building ECCS Pump rooms. A justification, technical discussion, 1 and no significant hazards analysis, at:d environmental analysis to support i I

this change is provided in the attachment.

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-turrently, we have begun:the Unit 2 routine refueling outage that is

-scheduled for approximately 81 days. Station areas and equipment that are currently unavailable for.use at this time, which are involved with approval of this amendment, are necessary to conduct operations associated with equipment decontamination -laundry decontamination, contaminated parts warehouse issuance, hot umchine shop activities, and solid radioactive waste processing and storage.

As an interim measure we have performed a review and taken actions allowed

. by existing Technical' Specifications so the laundry, decontamination area

.and contaminated parts warehouse can be used during the outage. Due to our need for the remaining areas to support our Unit 2 refgaling outage, we request NRC approval of the proposed amendment, as supplemented, as soon as J practical. 1 Pursuant to 10 CFR 50.91(b)(1)., the appropriate North Carolina official is

'lso being provided a copy of this amendment request.

a lv Should there be any questions or additional information ceeded to resolve this matter, please contact Steve LeRoy at (704) 373-6233.

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Very truly yours, 0?Q()o L Hal B. Tucker g{

p l }  : On Mlr^KM E j8R'*!BME % ' $

[' September 4,^1990

-U.S. Nuclear Regulatory Commission k ATTNt Document Control Desk' Page 2 s, , .

SEL574 Attachment xct Mr. S.D. Ebneter, Regional Administrator U.S. Nuclear Regulatory Commission, Region II 101 Marietta Street, NW, Suite 2900

' Atlanta, Georgia 30323 Mr. Dayne Brown, Chief Radiation Protection Branch Division of Facility Services Department of Human. Resources

, 701 Barbour Drive -

Raleigh, N.C. 27603-2008 Mr. P.K. Van Doorn NRC Senior Resident Inspector McCuire Nuclear Station Mr. D.S. Hood, NRC Project Manager Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 2(555 Mr. T. Reed, NRC Project Manager Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Wa'hington, s D.C. 20555, e

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September 4, 1990' ,

' ' + U.S. Nuclear Regulatory Connission' [

, ATTN: Document Control Desk i: .

< Attachment No. I r

Duke Power Company >

- McGuire Nuclear Station ,

i Description / Technical Discussion, No Significant Hazards Discussion, and  ?

Environmental Impact Discussion  !

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Backaround I

By letter dated October 15, 1987 to the NRC, Duke Power Company (DPC) i requested'a Technical Specification (TS) revision for McGuire Unit 1 and 2 to TS 3/4.7.7, Auxiliary Building Filtered Exhaust Ventilation.(VA) System. i that' consisted of the following changes:  !

c Provide a 7-day Action time for 1 train of VA-inoperable due to  ;

inoperable illter package, j l

b. Provide a 72-hour Actior. time for 1 train of VA inoperable due to  ;

inoperable flow path.

c. Provide a 7-day Action time when 1 train of VA is unable to maintain ,

.25" WG.

d. Provide a 72-hour Action time when i train of VA is unable =to maintain  ;

a negative pressure.  :

e. P:; ovide a 24-hour Action time with both VA-trains inoperable. ,

f. Replace term " charcoal" with " carbon".

g.- Replace term " ANSI N510-1975" with " ANSI N510-1980".

h. Replace current carbon sample test temperature and acceptance criteria (80'C and 99%) with 30*C and 90%. ,

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1. Replace "720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br />" with "1440 hours0.0167 days <br />0.4 hours <br />0.00238 weeks <br />5.4792e-4 months <br />" of carbon absorber operation.

By letter dated May 11, 1989 DPC requested an additional change to TS 3/4.7.7 that would-reduce the TS required flow rates from 54,000 CFM +/- 10%

for Unit 1 and 43,000 CFM +/- 10% for Unit 2 to 45,'700 CFM +/- 10% for Unit .

.1and-40,500 CFM +/- 10% for Unit 2 respectively. Thic request was the .

result of an extensive modification to the McGuire facility that added a Waste Handling Building to the station. This modification provided improvements in the following areas Radioactive waste handling and y

-compacting areast Contaminated laundry processing facility; Decontamination

• facilityt'and,' Waste Solidification area. Additionally, new Chemistry.

laboratories and Radiation Protection office areas were provided. ,

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, September 4, 1990 L

U.S. Nuclear Regulatory Commission Attachment No. 1,

- Within the new Waste Handling Building, additional 1NAC equipment _was added in combination with the existing HVAC egalpment to serve these new areas and existing areas that are now encompassed in the Waste Handling Build eg. Due to the capacity of the new INAC configuration and because it now services some of the areas once serviced by the VA system,'the required flow rates of the VA system needed to be reduced. Please reference our submittal dated May 11, 1989 for further details.

Description'/ Technical Justification The purpose of this supplement to our previous submittal is to revise the requirement to maintain a 0.25" W.G. negative pressure as referenced'against

- outsido pressure,in item c. above to 0.125" W.G.

The design basis for the VA' system as discussed in McGuire FSAR Section 9.4.2 is to:

1. ' Provide a suitable environment for the operation of equipment anu personnel access as required for inspection, testing and maintenance; Maintain the building at a slightly negative pressure to minimize out

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1eakage.

3. Provide purging of the building to the unit vent. The air exhausted to the environment from potentially contaminated areas is monitored and f11tered, as required, so that the limits of 10 CFR 20 and the TS are not exceeded: and.

-4. . Provide a suitable environment for the operation of vital equipmeht during an accident.

(Note: 10 CFR 100 values are applicable for accident situations.)

Our proposed amendment dated October'11, 1987 added to the second design basis in that the ECCS pump rooms will be maintained at a negative pressure of greater than or equal to 0.25" W.G. relative to the outside atmosphere

<during post accident system operation. Prior to the October 1987 submittal,

< testing was performed to demonstrate'our ability to meet the 0.25" W.G.

requirement. At that time'we met the requirement with additional margin.

Subsequently, as described above we added a modification that resulted in an additional change to reduce VA system flow rates. Prior to the completion

• of this modification, additional testing was performed to determine if all flow and pressure requirements could be met. When testing was performed 9e determined that the 0.25" W.G. negative pressure cwid not be achieved, The exact reason (s) we could not meet the 0.25" W.G. requirement could not be determined.. One possible reason that the previous results could not be

-repeated is that the alignment of interfacing systems may have originally been non-conservative. Another possible reason is that we vy have over time' experienced some Auxiliary Building integrity degradativ. We are currently investigating this possibility.

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' U.S. Nuclear Regulatory Consnission Attachment No. 1: 3 i

Subsequently when we tested in the post modification simulated

. configuration, we did test in a very conservative configuration that will be

' ' discussed below.

~In an~ effort to achieve the 0.25" W.G. negative pressure we have-inspected

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I the VA system by performing a walk down of the ducting to include an inspection of the dampers, registers, etc. After completing the necessary maintenance, adjustments, and flow balancing, we have-determined that'the i VA system cannot achieve a 0.25" W.G. negative pressure in the proper test.  !

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. configuration. Therefore, to satisfy the need to have a measurable negative

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pressure requirement that' ensures-adequate removal of post accident ECCS-Pump' leakage, we propose that 0.125" W.G. be substituted for the'more l- ,

restrictive requirement of 0.25" W.G.  !

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The justification and technical basis for this change are discussed with  ;

respect to the following areas: j l

1. ;The physical layout of the pump rooms and the pressure test locationst.

2. Discussion of the ECCS pump room testing including system alignment, l instrument error, and outside atmosphere reference points and, J 3.- The adequacy'of 0.125" W.G. to ensure filtration of ECCS pump leakage to mitigate the radiological consequences of iodine released during '

accident ~ conditions.

' Location of Pump Rooms The ECCS pump rooms consist of the following rooms: ,

y Room Il Descriptf.n_ Unit Elevation 500 ND Pump Room IB 1; 695' '

501- ND Pump Room 1A 1 '695' ~,

502 NS Pump R'oom 1A 1 695'

-503 NS Pump Room 1B 1 695' 504 NS Pump Room 2B 2 695' ,

505 NS Pump Room 2A 2 695' 506 ND Pump Room 2A 2 695' '

507 ND Pump Room 2B 2 695' 626 NI Pump Room 1B 1 716' 627 CC Pump Room 1A 1 716' 628 NI-Pump Room 1A 1 716' 629 PD Pump Room 1 716' 630 CC Pump Room 1B 1 716' 633 NI Pump Room 2B 2 716' 634 CC Pump Room 2A 2 716' 635 NI Pump Room 2A 2 716' 636 PD Pump Room 2 716' 637 CC Pump Room 2B 2 716'

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.f g September 4, 1990; h U.S. Nuclear Regulatory Commission t

Attachment No. I b Key to Acronyms: CC - Centrifugal: Charging ND - Residual Heat Removal

! NI ' Safety Injection NS - Containment Spray PD - Reciprocal Charging Enclosure 1 to this submittal shows the locations of all of the ECCS pump rooms. At'each elevation 695' and 716', the Unit 1 and Unit 2-pump rooms are accessible from a common hallway. These common hallways also act as air transfer corridors, allowing exhaust air flow to communicate between rooms associated with Unit 1 and those' associated with Unit 2.

Pressure readings.were taken from two locations on each.of the two pump room elevations. Enclosure No.'1 shows the locations at which readings were taken.

Test Results and Measurement Method The VA system is tested for both flow rats and ECC wu t- es..sure with the system aligned in a post accident configuratic . , n- E a single failure. Test alignments are as follows:

TEs i 4 #2 i COMPONENT ALIGNMFht ALIGNMENT l

VA Filtered Exhaust, ABFX-1A ON OFF VA Filtared Exhaust ABFX-1B ON OFF 3' VA Filtered Exhaust, ABFX-2A 0FF ON VA Filtered Exhaust, ABFX-2B 0FF ON.

Note 1 VA Unfiltered Exhaust, ABNXF-1A 0FF OFF VA Unfiltered Exhaust,.ABNXF-1B 0FF- 0FF VA Unfiltered Exhaust, ABNXF-2A 0FF OFF VA' Unfiltered Exhaust, ABNXF-2B 0FF OFF VA' Supply Units ABSN-1A 0FF OFF VA Supply Units, ABSN-1B 0FF OFF VA Supply Units. ABSN-2A-0FF OFF ,

.VA Supply Units, ABSN-2B 0FF OFF

- r Note 2 VF Supply Unit FPSN-1 ON ON VF Exhaust FPXF-1A ON ON VF Exhaust FPXF-1B ON ON VF Supply Unit FPSN-2 ON ON j VF Exhaust FPXF-2A ON ON VF Exhaust FPXF-2B ON ON Note 1: These fans have LOCA and Blackout (B/0) trips in non-safety class control circuits. Verification of trip is required.

i Note 2: These fans receive neither LOCA nor B/0 trip and are assumed "on" (unless on de-energized buss) or verified "off".  ;

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September 4 1990 _ .

df U.S~. Nuclear Regulatory Commission y, Attachment =No. l' Key.to Acronyms: VA - Auxiliary Building Ventilation VF - Fuel Pool Ventilation g Test Alignment No. 1 simulates a plant LOCA with a Unit-2 filtered' exhaust-failure. Test Alignment No. 2 simulates a plcnt LOCA with a Unit i filtered

' exhaust failure. The alignment of other ventilation systems.has been

' considered. The VF system alignment is included because the exhaust fans from this system utilize the. unit vents, as do the VA system exhausts.

1The oute de air reference point is located just outside the VA system supply unit intake plenum on elevation 786'. Enclosure No. 1 shows tho' general

location, while Enclosure No. 2 provides a more detailed sketch of the outside reference sensing location. Poly tubing (1/4" diameter) is routed down through the duct shaft to each location. This temporary arrangement is sufficiently shielded by parapet walls so that meteorologica1' conditions should not affect instrument readings. Since the VA system supply units are

- "off" during testing, velocity around the intake plenum is essentially zero (0).

A Nuclear Station Modification will be planned and implamented to provide 2 permanent external diffuser to be used in conjunction with periodic VA system TS testing. Currently, we plan to use a a Brandt model B-SPP2280.

Enclosure No._3 provides dimensional and error data for this diffuser.

Quarter inch tubing will be routed from the end cap to each test location.

Differential precsure is measured using an AIRDATA multimeter. For differential pressure readings the instrument accuracy is 12% of the reading

• t one digit (See Enclosure No. 4).

NRC Information Notice No. 86-76 was used to evaluate the measurement error due to the static fluid columns. It has been determined that no correction is required.

Test results are summarized below.

Pressure Measurement Alignment No. 1 Pressure Alignment No. 2 Pressure-Location 695-A 0.21 in. W.G. 0.17 in. W.G.

,= 695-B 0.21 in. W.G. 0.17 in. W.G.

716-A 0.215 in. W.G. 0.18 in. W.G.

716-B- 0.215 in.-W.G. 0.18 in. W.G.

.733-A Not Tested 0.14 in. W.G.

E 750-A- Not Tested 0.13 in. W.G.

. Testing results_have been repeated over a period of 3 weeks with little

' deviation from the above values. Differential pressures are consistent over each floor which indicates that one exhaust train is pulling the whole floor down to the same negative pressure. Readings were most sensitive to changes within the bui!61ng envelope, such as opening doors.

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[ , .- ' September '4, 1990 U.S. Nuclear Regulatory Commission Attactment No.1. ,

' Adequacy of 0.125" W.G. Negative pressure t To determine whether.0.1 M" W.G. of negative pressure in the ECCS pump rooms is adequate to filter ECCS pump leakage during a design basis accident,.the conditions'of adequacy have been established. Our. interpretation of the conditions of adequate' negative pressure are as follows:

a. Contain contamination by. establishing that the suction from the Unit 2 ventilation exhaust (weaker train) located in the ECCS pump rooms of

. that unit will collect "and thus process contamination frors the Unit 1 ECCS pump rooms; and,. .,

2. Establish that atmospheric wind conditions will not adversely affect the ability of the ventilation systes4 to maintain the 0.125" W.G.

negative pressure in the ECCS p'Lp rooms.

- The ~ ability of,the weaker Unit 2 train to establish adequate suction from the adjo ming Unit.1 ECCS pump rooms has been established through testing.

With the system in test alignment No. 2, smoke sticks were taken into the hallways common to Unit 1 and 2 pump rooms at each elevation. Flow to the L . Unit 2 pump rooms was clearly established (see Enclosure No. 1 for flow

. direction arrows).

Containment of any contamination on the lowsr plant elevations was further established by measuring the negative pressure on elevations 733' and 750'.

These elevations were negative with respect to atmosphere, and were slightly

-less negative than the lower plant elevations which will deter air flow seepage from the pump rooms through the ceiling to the higher elevations.

The following arguments can bn made in justifying why wind will not effect the ,

ability of the VA filtered exhaust system to maintain at least 0.125" W.G. .I negative pressure in the ECCS pump rooms. Ground elevation at McGuire is at

'760' sea level. The ECCS pump rooms are located on elevations 695'and 716',

or 65' and 44' below ground, respectively. Two floors separate the 716' elevation from' ground level at.733' and 750'. Wind effects will tend to affect building pressure in areas above ground level. These intermediate

• floors act as a buffer to pressure variations in the Auxiliary Building at

's lower elevations'. By maihtaining elevations 733' and 750'. at a slightly

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negative pressure with respect to outside atmosphere, the ability to lessen the effects of wind induced pressure variations at the lower elevations is enhanced. . Separation by distance, physical concrete barriors, and the negative pressure gradients on upper elevations all assist in reducing any influence wind will have on the ability of the VA exhaust to maintain at least a 0.125" W.G. negative pressure in the ECCS pump rooms.

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[ >, September 4, 1990 U.S. Nuclear Regulatory Commission g Attachment No. 1 All the ECCS pump rooms are located in the core or center of the Auxiliary Building. The majority of the Auxiliary Building is surrounded by other buildings that are physically attached to the Auxiliary Building (See Enclosure No. 1). The Turbine Buildings, Reactor Buildings, Equipment Staging Buildings, and Sersice Building all act as physical barriers to wind loading. Additionally, the VA system exhaust fans discharge out the Unit 1 and Unit 2 vent stacks. Stack design, height, and size assist in limiting wind influence on discharge flow.

In summary, we have determined that the influence of wind on the McGuire Auxiliary Building should not impact our ability to maintain a negative pressure of 0.125" W.G. in the ECCS pump rooms during post-accident conditions.

No Significant Hazas is Discussion Duke Power Company has determined that this revision to our previous amendment does not involve a significant hazards consideration. Operatien of McGuire in accordance with the proposed spendment would not: (1) Involve a significant increase in the probability or consequeaces of an accident previously evaluated; or, (2) Create the possibility of a new or different kind of accident previously evaluated; or, (3) Involve a significant reduction in the margin of safety. Although this requirement is a decruase in our previously proposed requirement, it has been demonstrated, as previously discussed, that a negative pressure of 0.125" W.G. will ensure post LOCA leakage in the ECCS Pump rooms is drawn and processed by VA system. Additionally, the No Significant Hazards discussions contained in nur submittal dated October 15, 1987 and May 11, 1990 remain valid.

Therefree, DPC concludes tha proposed revision does not involve a significant hazards consideration as defined by 10 CFR 50.92.

Environmental Analysis As previously stated in out submittal of May 11, 19, the gaseous curie release from plant operations will not increase as a result of this proposed amendment. The improved waste handling capability will reduce solid radwaste and liquid radwaste ve.lume. The proposal to revise the negative pressure requirement does not change the anvironmental assessment previously stated in our submittal of May 1989.

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