ML20097A692

Forwards Revised Page 5-1,Table 5.1-1 & Page 8-11 of Rept, Evaluation of Paint & Insulation Debris Effects on Containment Emergency Sump Performance. Response to NRC Question Re Blockage of Narrow Flow Passages Encl

ML20097A692
Person / Time
Site:	Comanche Peak
Issue date:	09/07/1984
From:	Ballard R GIBBS & HILL, INC. (SUBS. OF DRAVO CORP.)
To:	George J TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
References
GTN-69432, NUDOCS 8409130346
Download: ML20097A692 (7)

Text

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4A Gibbs B Hill. Inc.

'8 11 Pem Plaza

NewWk NewYbrk10001

.(f 4438

. Domestic:127636/968694 Intematonal:428813/234475 f' A Dravo Company

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September 7, 1984 GTN- 69432 Texas Utilities' Generating Company Post Office Box 1002

' Glen Rose, Texas 76043

. Attention: Mr. J. B. George Vice President / Project Gen. Manager Gentlemen:

TEXAS UTILITIES GENERATING COMPANY COMANCHE PEAK STEAM ELECTRIC STATION -

G&H PROJECT NO. 2323 GIBB3 & HILL PAINT REPORT Based on our telephone conversation of September 5, 1984 with S.B. Burwell and C. Li of the NRC, we are. attaching the following regarding the Report on " Evaluation of Paint and Insulation Debris Effects on Containment Emergency Sump Performance" June 1984.

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, Attachment'1: Revised Page 5-1 and Table 5.1-1 of the Report.

Attachemtn 2: Revised Page 8-11 of Section 8.0 attached to Gibbs & Hill letter GTN-69345 dated August 15, 1984.

Attachment 3: Response to NRC question regarding potential for blockage of narrow flow passages near the sumps.

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GTN-69432 September 7, 1984 You are_ requested.to submit the above information to the NRC after review.

Very truly yours,

@ BS & I

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Robert E. Ballard, Jr.

Director of Projects REBa-MC:sce 1 Letter + Attachment cc: ARMS (B&R Site) OL J.T. Merrit (TUSI Site) lL R. Tolson (TUSI Site) lL, lA R. Iotti (EBASCO, N.Y.) lL, IA H.C. Schmidt (c/o Westinghouse Bethesda)+(Dallas) 12L, 12A-DC "nward Berkowitz (Westinghouse Pa) lL, lA (S. Burwe D g/L.Bethesda) IL, lA (Telecopy) 4 P'

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5.0 WATER VELOCITIES Following the_ post-LOCA. safety injection phase, wnen the contents of the RWST-are exhausted, valving is aligned to provide for a recireulating flow of water from the containment emergency sumps.

The water flowing through various zones provides the motive force

,for the. transport of debris'to the containment emergency sumps.

The available' water velocity in a given area of the containment determines the transport potential for the debris.

The object of the water velocity analysis _ is to establish migration patterns for debris within the containment. The flow pattern within the containment is complex du'e to the presence of equipment. supports, shi eld walls, openings in compartments, floor openings and related hydraulic resistances. The methodology used to estimate recirculation flow velocities within various regions

.of the containment is similar to that discussed in NUREG/CR-2791.

5.1 Sources of Water The sources of water inside.'the containment following a LOCA determines the water level. The water level in turn determines dae flow area for calculation of water velocities in various zones of the containment. The sources of water considered in Ethis evaluation are given in Table 5.1-1. This table gives the maximum available water sources, the minimum and maximum amounts of water expected to-be in the containment following a LOCA. The difference between.the maximum and minimum water source is in the refueling water volume. The maximum water is based on the tank useable-volume, i.e., 2 percent above high water level set point Eto the pump' suction. nozzle. The minimum water volume is based on

'the refueling water tank capacity from 2 percent below the high water level set point to 2 percent above the empty level set point (the empty level set point is 6 ft. 4 inches above the pumps suction nozzle.)

5.2 Water Levels at Sump Elevation (808 ft. EL)

The" high and low water levels were calculated using the maximum and minimum water inventories given in Table 5.1-1. These calculations were cased on the actual net volume available at

< 808 ft. EL. in the containment. The net volume was calculated by i determining: the gross volume and deducting the actual volumes of equipment, foundations, reactor cavity and other basement areas

-below 808'ft'. elevation. The calculated high and low water levels are.also presented in Table 5.1-1.

I E REVISED 5-1 SEPTEMBER 6, 1984

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.. S Wrs.E T 2. t 9 L TABLE 5.1-1 WATER INVENTORY AND LEVELS

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. Available Maximum Minimum Capacity, Quantity, Quantity, Source cu.ft. cu.ft. cu.ft.

Reactor Coolant 12,740 12,740 12,740 Refueling Water Storage Tank 70,400 67,990 53,570 Accumulators 3,810 3,810 3,810 Miscellaneous 920 920 470 Total 87,870 85,460 70,590 Water Level (ft)(18 ,

817.5 814.8 Note:

(1) Based on calculation of actual net volumes available excluding equipment volumes, foundations, reactor cavity and other basement areas below 808 ft..EL.

REVISED 5-2 SEPTEMBER 6, 1984

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.. Moreover, in the free flow orifice of two inches, the velocity at the fine screen is about 1.18 fps and the velocity at the coarse screens inlet is about0.4fpsf: these higher velocities the particles vill tumble and behave mere as an equivalent sphere than flakes.For the lighter particle,

.th 1/8 inch steel paint chip with a specific gravity of 1.5 and thickness

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-of 5 ' mils, ibe t'ernical velocity of an equivalent apbere would be about 0.28 fps. Tualling particles at this velocity would be unaffected by the l 2 inch free area.

In reality the particle will behave socevhere betveen the case of the untu=S, ling flake and the tumbling flake, and hence it is expected that an apprezin. ate 2-inch band of screen at the top will remain free. It a.ast also be stated that the assu=ption of all particles of paint having a specific gravity of 1.5 is conservative, as is the assumption that all will have an equivalent diameter of 1/8 of an inch. The uncertainty in this type of analysis is discussed later in this section .

In additior. to the free band of fine screer.s O.st wou3d rerain on area of t.he a31 sides of the s an.p , O,e r e is s on.e additier.a1 screer,which vill not be blocked.

The amount of additional open area is described herein after.

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.e RESPONSE TO NRC QUESTION

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'NRC Quest' ion; There are columns near.the sumps which create narrow flow passages. ..-If~ paint debris reaches these pasages, they-

.may be blocked by debris accumulation. Evaluate this potential-for~two typical locations: a) near Column-3 and

'b)-near. sump-' screen sections A2 and Bl.

Response:-

Paint' debris accumulation will not occur in.the narrow flow

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passages because the higher water velocities in these pas-sages will tend to' move'the debris away from the passages.

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,Even if paint debris accumulation at the narrow passages is postulated,.'such an' accumulation will be-uniform on

'the floor. 'However,:for the purpose of analysis, we have-

.very. conservatively assumed that.all the paint. debris will

' form'a mound.at the passage with a 45' angle of repose.

. The results-of calculations for evaluating the potential

-for blockage of the two typical passages is as follows:

lA) -Passage at Column-3 (see attached figure)-

The~ volume of; debris required to block the passage is 216 cu. ft. The available debris at this-

~ location is determined by conservatively assuming K that all debris at screen sections D3 thru D7 will accumulate attthe passage.= The quantity of debris lat--screen sections D3 thru D7 was previously calcu-lated and presented in Table.9.1-2 (attachement to

.GTN-69345, dated August 15, 1984).- From Table 9.1-2, lthe quantity"of debris available for blockage of the passages-at: Column-3 is only 82 cu. ft.

b) Isosage at-Screen Sections A2 and Bl.

4 The calculated quantity..of debris required to block this passage is 138 cu. f t. . The total quantity of debris'at Screen Sections 31, A2,-and'B1 thru B7 is only 22 cu. ft.

,From the above, Tit is concluded that there is no

. possibility of blocking flow passages near the sumps,

- because the available paint debris.is considerably less'than:the quantity required to cause blockage.

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