ML20235C907

Forwards Request for Addl Info Needed to Continue Review of Gessar Application,Including Discussion of Steam Condensation Rates Assigned to Containment Sprays & Heat Sinks.Info Requested by 740509

ML20235C907
Person / Time
Site:	05000000, 05000447
Issue date:	03/26/1974
From:	Stolz J US ATOMIC ENERGY COMMISSION (AEC)
To:	Hinds J GENERAL ELECTRIC CO.
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FOIA-87-40 NUDOCS 8707090574
Download: ML20235C907 (17)

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I[D-UNITED STATES i

ATOMIC ENERGY COMMISSION

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FIINE'O KCBS i

WASHINGTON. O.C. 20545

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MAR 2 61974 Pht

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-a Docket No. STN 50-447 p

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General Electric Company g g.',

8-ATTN:

Mr. John A. Hinds, Manager ce iG Safety and Licensing

[Ed C

e" 175 Curtner Avenue San Jose, California 95114 Gentlemen:

In order that we may continue our review of you( rGESSA_Pfapplication a

additional information on those matters set fortn in the enclosure is needed.

To maintain our licensing review schedule, we will need a completely adequate response by May 9, 1974. Please inform us within 7 days after receipt of this letter of your confirmation of the schedule or the date you will be able to neet.

If you cannot meet our specified date or if your reply is not fully responsive to our requests, it is highly likely that the overall schedule for completing the licensing review for this project will have to be extended.

Since reassignment

.of the staff's efforts will require completion of the new assignment prior to returning to this project, the amount of extension will most

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likely be greater than the extent of delay in your response.

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l The questions in the enclosure have been grouped by sections that

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correspond to the relevant sections of GESSAR, and the question numbers continue consecutively from previous letters.

Please contact us if you desire additional discussion or clarification of the material requested.

4 Sincerely, j

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O ohn F. Stolz, Chief L,i'cht Water Reactors Project Branch 2-1 Directorate of Licensing

Enclosure:

GESSAR Request for Additional Information I

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(see next page)

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Cencral Electric Company MAR 2 01974 J

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Mr. W. Gilbert, Manager Safety and Standards General Electric Company i

175 Curtner Avenue l

San Jose, California 95114 Mr. L. Gifford, Manager Regulatory Operations Unit General Electric Company 4720 Montgomery Lane i

l Bethesda, Maryland 20014 M

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.g s N ENCLOSUPI v

REQUEST FOR ADDITIONAL INFORMATION GENEPJJ., ELECTRIC CO>fPANY GESSAR PLANT a

DOCKET NO. STN 50-447 i

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30 Design of Structures. Comnonents, Iouinment and Srstems 3 160 The analysis of containment vacuum breaker sizing presented in response to question 3 133 requires the followin6 additiona:

3 information:

a) clarify the inconsistency between Table 3.8 4 and Table 6.2-19 b) specify the signals which actuate the containment, spray system and describe the operation of the time delay device which trecludes simultaneous operation of both i

f core and containment sprays.

2 c.)

specif r the flow area of the vacuum breaiers in teres of h/ Nri'.

1 d) justify your assumption of an air-vapor mixture flowing through the drywell vacuun breakers since air-only flow would re.nove more noncondensibles from the containment.

e) in regard to Figure 3.8-34, discuss the reasons for the drywell pressure lassing.the containment pressure by more than 0 5 psi, the setpoint. for the drywell vacuum a

broa':e rs.

f) discuss the steam condensation rates which were assicned to the containment sprays and heat sinks.

g) for t.e ;ostulat4:d rupture of t?.e Reactor '.7ater Cleanup System (7llCU) line it appears t5at the displacement of containment air into the drywell could cenerate a high drywell pressure signal and cause isolation of the r.otor operated valves which are in series with the coats. intent vacuum brea::ers as discussed on page 3.8-4h of GESSA2.

Containment spray operation could reduce the containment pressure below atmospheric.

The preseure could go be.Jond the containment design nesative internal pressure of

-0.8psig (P 3. ^-4) since the spra,"s would not affect the drywell pressure, and the isolation signal to t'e motor operated valves would be caintaired.

Discuss the need for and availability of containment vacuum relief under these conditions.

3.161 Section 3.8.31.1 of GTSSAR, " Description of the Drywell

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Vacuun Relief Syster", discusses protection of the. containment j

. vessel and co"tain: cent vacuum breakers, Clarify tnis

apparent dicerepancy.

'3.162 Your resfonse to question 3.82 concerning the effects of post-LOCA suppression pool swell has not been subcitted.

In your resjonse, describe t'.e analytical :.:ethods which were used to deter:uine the dynaaic loads and how there loadc were incorporated in the structural design.

Trevide the magnitudes of these loads used in the structural analysis

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conducted by the structural designer.

Specifically consider the. following:-

a) pool swell due to drywell air carryover; b) impingement effects during vent clearing and vent flow; I

c) seismic induced pool motion; j

1 d), circumferential or radial pool wave effects d ue to non-

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uniform vent flow and/or non-uniform air addition to the pool.

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'3 16'2.1 For the circumferential or radial pool wave effects' dis-'

cussed in d) ahove, discuss the otential for transient vent uncovery or pool separation and re;ultant steam bypass of l

the. suppression pool.

3 162.2 Provide similar information as outlined in 3.162 for the case of a small break LOCA followed by actuation of the Automatic Depressurization System (ADS).

3.163 section 311.2.1.3.2 of G2SSAR indicates the local environ-s ment for a steam line break inside the containment and out-side the dryttell.

Indicate wPat equipment will be subject-to these effects of the steam line treak environment and how thoce environmental conditions ciere considered in the development of the environmental envelopes for eac'h of the e ffec ted equipr.cnt.

In addition,. discuss the considerations given in-the selection of the environmental envelhpes for the effects of localized steam impingement and/or spray water cuch a.; that which. night occur to couipment located in the containment as a result of direct drywell bypass.

3 164 Table 3.11.1 in CTSSAR lists the accident environment for safety related systems located in the drywell.

Justify 1

-3 psig as the assumed minimum pressure f or the drywell i

since the drywell relief valves are not designed as engineered safety features.

It is our position that 30 psig s!;euld be used for the maximum design internal pressure.

Also revise page 3 11-7 to be consistent with these values.

The ecm-bustible gas control systets should be included in Table 3 11.2.

3 165 The response to suestion 3 68 is incomplete.

The magnitude and the oscillatory nature of the LCCA forces are not pre-sentod-in Figure 4.2-10 as stated in Section 3 0.1 5 Deceribe the LOCA fo*cing function acting on reactor internal structures.

In adddtion, since :.00A and SSE may not be entirely uncorrelated, the rule of using square r ot of the sum of squares may not be justifiable.

The acceptable I

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combi' nation of LOO.i and SSE effects is considered as' linear I

e numerical. superposition of maximum responses.

3 166 The. response to Question 3.55, referenced G.E.. Topical Report NEDE-10813, "PDA-Pipe Dynamic Analysis Progran for Pipe-Rupture Movement.".A preliminary staff review cf this report has resulted in the following questions:

3.166.1 The sinplified system rodhling of the piping and the re-asstatedin"EDE-lOY13maybeacceptable.straint for corputinr th 1

However nunerical examples providing comparison with representative so,lutiens using nore rigorous dynamic analysia and/or suitable enperi-mental results are necessary to der.onstrate the adequacy of the prorosed methods, The staff requires a cercittent to provide representative numerical examples durin.; the PSAR stage of individual plant reviews to justify ~the simplified analytical models ecployed, 3.166.2" As indicated in NEDE-10313, the pipe whip restraint desirn i

is based on analyses using an enorgy balance approach, che state of ::aximum stress or strain of the restraint is based on the computed aximum: deformation at the end of the first

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quarter cycle of the. response.

'ionever, in certain circ';.-

stances nanicum deformation may occur latar than the first quarter c;cle of response.

'/!e agree that the rebound si:nld not cause uajor concern when the restraint remains elastic and will still have ample desicn margin to absorb additi nal energy.

However, reben.nd may cause a problem if the restrair.t i

reaches'its fsesign limit but the bro':en pipe is still in t'.e i

elastic state.

.In addition some studies indicate t' at re-bound may occur due to the e,ffects of the 1-itial tr=nsient of the jet thrust.

An arrlification factor of 'l.2 s5 ?uld 3

therefore te a r. plied to the jet tPrust in addition to the thrust coefficient.

The staff will reon I

a thrust force az;11fication factor not' ire a corrittent that less than 1.2 cust be ceployed to determine the forces to be used in rectraint l

design.

3.167 Table 3.2.1 indicates the only seistic Category I source of makeup water is the R"R system.

It is our position that a fuel pool rater makeup source independent of the ?".2 shculd be provided which n:ets the seis.?.ic Category I require:.e:t.

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6.0 EncinmereTSafety Features t

6.90 The Pressure Suppression Containment System (PSCS) anal:* sis code contains a subprogram for vent clearing.

is also used to compare with the test results. This sub:.rcirar Describe the numerical solution method that is employed in this sub-prosram and supply a justification for the nodalization that has been colected.

Discuss the e:mected accuracy of the solution that is obtained by the numerical solution 1.et'.ed.

What other assurances are there that the numerical solution method corresponds to the set of equations to be a 1ved?

6.91 In a letter from J. A. Hinds to 2.C. De?oung dated Ja.uary 30, 1974 jou have described the analytical modeling used to calculate the blow-down from a postulated recirculation line break for drywell pressare response analyses.

The codel is seperated into s' ort and long-term periods ' tith res;ect to its treatmer.t of th loop side of the breel,t.e mass flow from the recirculation 1

The *.:odel applies a flow coeffi:1e.t of 0 5 to the 1:cody correlation for the loop side nr.til the inte: rated mass releave equals the iritial loop esas inventory.

After depletion, the loop-ride unss fic; is based o-i<cody flow t5 rough an arca equivalent to ten jet pump nozzles and the cleanup line.

.7e have. reviewed the above modeling techniques and currently believe that:

a)

The assumption of jet pump-cleanup line restricted f' o is acceptable it the lo.c term.

b)

The use of the 0 5 coefficient in the short tert is not j

acceptable and the following alternate assumptions should be considered for the short term:

1) the recirculation loop should be modeled as a single and separate volume with the initial subceoled :a:sr mass aid energy equal to the inventory of the 1 cop.

ii) the break area associated with this tolute should equal the area of the recirculation pipe.

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iii) the mass flux out the break should be co=puted based on the Moody correlation.

iv) mass addition to the volume should be eemputed based on the arca of ten jet pump nozz1cs and t'. e cle nup line with the corresponding differential presse.re between the reactor vessel cnd the single node simulation of the recirculation loop.

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The above model should be used until the mass flow out the break is rectricted by flow t'rouch the jet pump nozzles and the cleanup line, at which time the long-term nod'el becor.es appropriate.

In either case the total ~ mass and energy addition to the drywell is tFe sum of the cohtri-i butions from the recirculation loop side and reactor. vessel side of the break as describcd in the.above referenced letter.

Therefore, in regard to the G3SSAR application i

provide the following information:

I 1.

A table of blowdown mess and enersy rates at various time incremental steps for a recirculation break hased on the atove specified codeling techniquas.

Show separately t'e contributions fron the vessel and loop

. sides of the break.

2.

Based on the above blowdown data, provid'e the drywell pressure response as a function of time.

6 92 Frovide the data used in your c:mputation of c'ontainaent pressure, ct the conditions of pod: contain=ent pressure, usin; tho equct$ons from the long-tors analysis in GESS;.2 i

Section 6.2.1 3.7.

6.93

'Vith res7ect to."our res onse to question 6.27 provide the results of an analysis of containment pressure and te.pers.t"re as a function of time for the following postulated conditions:

a) a small prinary system bren't which results in the maximuu duration of blowdown.

i b) l existence of bypass leakage between the drywel containmentequivalentto-approximatelyoneft}and (A/s/?).

c)' continuous operation of the contcirmont spray system.

Specify any initial conditions or assumptions used in the analysis which are not consistent with Table 6.2.1,B (on pace 6.2-67).

i 6.94 Specify the value of the inte of peak containment pressure.: rated decay heat at the time i

Also revise items 14 and 15 l

in Table 6.2-15 to express 1 *a--atoA values in Stu's as requested by 7.uestion 6.70.

6.95 The analysis of contain:.ent spray condensing capability

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presentad in response to Question 6.63 s'ould be based on e

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7-l 1100F service water and a heat 'exchancer capacity which is consistent with the data provided in Table 6.2.1.

In addition, justify your assumption of 75% spray efficiency considering the effects of the steam / air ratio in the containment.

16.96 The following inconsistencies have been noted in GESSAR regarding the lons-term containment response.and RHR heat i

exchanger capabilities.

Revise G S.9AR as @ pro

. provide. consistent information in these areas:priate to a)

Table '6.2-15 indicates the time of containrcent peak i

pressure as 30,560 seconds //hich is not consistent tiith Table 6.2.4, page 6.2-64 or Figure 6.2-11.

b)

The RHR heat receval rate shown on Figure.6.2-14 is not consistent with the heat removal rate c mputed using the data on page 6.2-65 and a peak pool temperature a

'of 179 F (Table 6.2-3).

0 c)

The data in (b) above is not consistent with the decay heat rate at the time of peak contnine.ent pressure as shown in Table 5.2-15.

6.97 From the design data provided in Table 6.2-1 and our recent discussions with you, plants referencing GISS!.R will have the option of selecting one of three RHR heat exc' ranger designs de;endiig on site service teter tetparature.

In addition, your res ense to Question 6.87 indicates that t're heat removal capabilities of the varicus heat exchangers will not be equivalent and therefore the tines and values of peak containment pressure and peak pool temperature will be a function of the particular heat exchanger desisn.

Therefore to establish the tir..es and values of containment pea'c pressure and. temperature for each alternate desi n, provide containment response analyses for the heat exchancer designs corresponds.; to 700 0

F and 90 F service rater.

If the RER heat exchanger size will be based on some fourth RER design provide the containment response analysis for that size also.

1 6.98' As requested by Questions 6.9 and 6.60, analyses of all subcompartments within the drywell and containment should I

be provided.

Subcompartments "thich have been identified on other similar plants include the sacrificial shield the drywell head recion, and compartments which contain ung,ucrded R?lCU lines.

To ensure that a complete resfonse is provided 9

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at this stace of the. review, our information requirements for each subcompartuent are listed below:

a) the blowdown rates and' energies (note Question 6.91

.above, for a recirculation line rupture);

b) the total-vent area; c)- the coreportment free volume; d)- - the peak ' calculated differential pressure and time at which the peak occurs; e) the design differential pressure; f) the' analytical methods used to deter: cine-the pressure response 1 cluding a description of the computer codes l

used; g) the values for flow coefficients used in c'ompartcent i

analysis and the basis for the selection of flow co-officients and h) a flow or bubble dingraa showing compartment voluuss, how they interconnect with other conp?rtments, and the flow areas throu-h their interconnecting pathways.

6.99 specify the design temperature and tressure. Tor the guard-pipes provided on high energy lines passing through the containment.

Also provide a list of all hi;h energy lines and their sizes that are equipped with a guard pipe.

6.100 Your'res:onse 'o Cuestion 6.57 is not cot;1ete.

Provide t

the following information concerning postulated ruptures-of Reactor ?!ater Cleanup System lines in the containment, a)

Specify the peak containment pressur6 associated with the worst R!CU line rupture.

b)

If orifices are provided in the R!CU system to linit blowdown-flow rates, specify the diaceter of the orific es.

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Describe the leak detection and isolation systems which are relied on to ter.T.inate blowdown from a RICU line

. rupture.

Specify the lapse tiues associated with ench system.

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6.101-Your' response to' Question 6.62 is not complete.

Provide the following additional information concerning the arranfe-ment of RH3 suction and return lines:

a) verify' that the EHR test lines shown in Figure 5.5-la i

s represent the post-accident EUR flow path.

b) justify your assumption of a homogeneous pool volute in Section 6.2.1.3.7 considering that all the IHR

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suction and return lines are located in a one third i

secter of the pool and that follocling post-accident pool drawdown the height of water above the suction lines'do not clearly encure mixing.

-6.102 Your restonse to Question 5.'61 does not justify the anal" sis 1

of drywell depressurization that is used in GCSSAR.

Exa:.ples of the deficiencies we have noted are the following:

1 1)

Initial' suppression pool ' temperature should be 110 F to 0

a be consistent with Table 6.2.1.

2). No justification is provided for the spray efficiency assu.:.ed in the analysis.

3)' Credit is taken for vacuum breaker operation although it is not a design basis for the vacuut breakers.

In response to the above co:ments provide either (1) t additional and cotulete substantiation of your current analyais or (2) provide a revised analysis showins the i

slowest possible depressurization time for the drytell a:d indicate its 1:.: pact on peak eniculated containment pressure.

Also specify the peak contal". ment pressure for the assump-tion of all drywell noncondensibles rennining in the con-tainaent for the duration of the long-term transient.

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-6.103-Figure 6.2.lc provided in res;cnse to Que.stion 6.74.1 does not adequately define the secondary containment boundary.

i Frovide t'ris information on drawin.;s of comparable detail as Ficures 1.2-2 throush 1.2-B in CISSAR.

1 6.104 Your response to Question 6.74.2 is not adequate.

provide f

the prorosed allowable limit for t':e fraction of total con-tainment leakace which could brpass the Standby Gas Treat-ment System filters.

6.103 Your responses to Questions 6.7541 and 6.75.2 are not n

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As requested, indicate those lines, by reference to Table 6.2 9, that c ould be open to the containment or drywell atmosphere and interface with the outside atmosphere following a loss-of-coolant accident.

Also indicate the number and type of leakage barriers w'-ich are assumed to be available considering a single active failure.

1 6.106 Your response to Euestion 6.79 does.not adequately justify.

the separation or protection against such things as fires,

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flooding, missilos,etc. pf Standby Gas Treatment System (SGTE' components.

Discuss th6 adec,uacy of the design with respect i

to the separation and protection of the 53TS fans, and the protection afforded the SGTS ducting from the shield building to the SGTS fans, filter trains and to the plant disch?.rge point.

l 6.107 Your response to questi'on 6.78 states that"a separate decay heat removal fan is provided for the Standby Gas Treattent System (SGTS).

This fan should be indicated on Figure 6.5-1.

In addition, justify al. lowing the SGTS filter carbon tem-I pcratures to reach 3100F (desorption temperature is 2750F) before actuating'the fire protection system.

6.108 Provide the following hdditional information with rerard to the Standby Cas Treatment System (SGTS):

6.108.1 Face 6.5-2 of GTSSAR indicates that the SGTS starts auto-matica11y following a "LCCA" signal.

Specify the signals (e.s., high drywell r;rescure, low water level) which are used to indicate a loss'-af-coolant accident.

6.103.2 Page 6.5-8 of GESfAR states that failure of the SGTS different pressure controller wou'.4 cause negative pressures within the secondary containme;;t to increase but remain beloi. the design differential pressure, 3 psid, of the auxiliary build-ing.

Specify the caxixum negative pressures that could occur and the design differential pressures of the ICCS pump roo s, shield building annulus, and fuel building.

6.109

!ith respect to GESSAR Section 6.2.5 3 3 5, discuss the potential for stray water to accumulate in containment sub-compartments and t'rereby provide a source of hydrogen - If the subeccpartments are not provided with sufficient mining, loca'_

concentrations could exceed 4 volume percent.

Discuss how ye; design will prevent local subcompartuents from exceeding a hydrogen concentration of 4 vol,ume percent.

6.110

?!ith respect to the analysis of dryrell mixing prior to the start of the hydrogen mixing system, presented in GESSAR Section 6.2 5 3.3.1, discuss the f ollowing:

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6.110.1-It-is our position that the.~.ixing system should have the capability to start at'10 minutes followins a LOCA.

Evaluate the potential for fla mable hydrogen mixtures exiting the reactor vessel assuming hydrogen generation rates which would yield a 4 v/o hydrogen concentration in the drywell at 10 minutes.

6.110.2 Assuming no bulk steaming in the reactor vessel,-discuss t,he' tanner Sy.w ich dilution or depletion of the steam s

inventory in the vessel dote was considered.

16.110 3 Discuss the potential for condensation of the entrained steam along the flow path from the vessel dose 1to the brea%

in the recirculation line.

6.111' In' the discuscion' of containment mixing prior to the start of the hydroren mixin system, prese-ted in G"5SAR Section 6.2 5 3 3 3, the a.nproach taien was.to estnblish the a

existence of turbulent natural convecticn at t.he suppression-pool surface.

Further substantiate your analysis as follor:s:

'6.111.1 Justify the selection of the full peel width as the char-acterictic len. th asscciatei with the Grashof number.

s 6.111.2 E:: tend your analysis to include the calculation of a cass transfer coefficient and show that the resultint mass trens-port will disperse the hydrosen'conerated at the pool surft:e.

6.111 3 Justify your contention on pase 6.2-60s that the containment will have turbulent natural convection since it annears 1

that the analysis applies only in the vicinity of the p ol

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surface.

6.111 4 Discuss the validity of your assumption of a sufficient temperature difference between the pool and containment atnosphere to t%.e. time period after n'-ich the suppression pool has reached its peak temperature.

6.112 Your response to questf on 6.S3 does not adequstely jurtify that the single sat.pling point availcble in the drywell and containment (followins a cinrle failure) is capable

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of detectinc non-uniform hydrogen concentrations.

It is our position that each redundant hydrogen analyzer unit should sauple a :.initum of two locations in sach the drywell and containment and that tS ere locations be justi-fled to be rey.-esentative of the bulk atr.nspheric conditions l

within each volut.:e.

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...O 6.113 Spebify the size and location of the hydrosen mixins syster inlet penetrations.

6.114 Discuss the separation and protectimn criteria which are applicable to the lines and components of the t" ernal recombiner system.

6.115 Your response to question 6.35 indicates that corrosien : f zine and alur.inum naterials itithin the containment f llorin-a loss-of-coolant accident has been considered as a source of hydro;en.

Discuss t'e source (s) of corrosive arents which could be present in the post-accident containment environment.

6.116 Your respense to questien 6.84 states that tfree inMrico'cs are incor; orated in the hydrogen uining syste.T desig. ' ore ter only tbc cecond and third are described.

Specify the first interlock.

6.117 Provide t' e raximum allowable suppression pool tempere.ture for both LOCA and relief valve operation co-ditions.

the initial terpcrature and taximum tee.perature in:"e..en:s List for normal o;eration and LOCA energy additions.

6.118 Yle have noted the followin: additional d ficiencies in G2SSAR Cection 5.2.4, Containment Isolation Systems, plesse i

revise GIGSAR to acconcodate these contents:

a) the purce exhaust line shottn on Figure 9 4-5b sSc:1d be incluged in Table 6.2 9 and Figure 6.2-15 b) the drywell purce line, penetration 31 in Table <.2 9

is shown to be norually open.

be closed during normal operation.?le require this line to c) 6.2-15 do not asree with Figure 6.2-16.the co. buctible Cas I

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6.119 It is our position that protective screen assemblies should l

be provided around the containment heat removal pipin-suction points in the suppression pool and sk.ould 're capC:le of preventins debris frou e.tering the impair the performance of system pumps,pipins thich could valves, heat ex-chancers or spray nozzles.

The desica of tS e screened area should be larce enouch to assure a low approacP velocity and preclude clo:31ng of the screening by lebris beinc c';: n_

against it.

Describe how your design moets this requirement.

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6.120' In the. event' of high radiation in the containment nurge the shield building annulus,: the ECCS pu.'p rooms,'and t'de

, fuel buildinc, you state that the exhausts are directed to

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the standby nas.treatet.ent system (SGTS).

To. meet the i

"as lov; as practicable" guidelines, the containmentcbu11 ding 1

. ventilation exhaust and the dry *:: ell purse exhaust should d

be treated to remove radiciodine.- The combined car >acit~y i

of' these ventilation systems far e:.:ceeds the. treathent capability of the.?~TS.

Additional means of reducine the releases. of radioactive v.aterials in raseous effluenEs from the plant ventilation systems need to be trovided in'either the G3 or bop design..

6.121.

It is our position that ' esign e::ternal cressure of the d

dryttell s,nould be 21 psid as noted on pa'ge 6.2-56..

Table 6.2.1 chows 20 psia.

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-6.122 Your' response'to cuestion 6.69 stated that the details

-regarding tne routing of the safety relief valve discharge piping vo the suppression pool ; tere not available It is our.?ositien that this piping should not penetrate.the dr"-

viell above tno level of the suppression pool.

DatM' r tbde pipes s'ould he routed down bety:een the weir wall a.!.d tb3

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before discharging into;the pool outside of the i

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' 9.0 Au"iliary Systems

-9;49 The description of the Fuel Building Pressure Control System t

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presented in GZSSAR Section 9 4.6 requires clarification as follows:

a)

. list any sections of the Fuel-Building which are not maintained at negative pressure during normal operation, b) specify the magnitude of the negative pressure which is maintained durinC normal operation and following a 100A.

c) the response to Question 6 44 stated that the Fuel Building Pressure Control.5ystem maintains the SGTS rooms at necative pressure during normal operation and following an accident..This does not appear to be consistent with Figure '9 4-6 which shows the SGTS roots connected directly to the SGTS.

9 50 The description of the Auxilinry 3uilding ventilation

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system presented in GISSAR Section 9 4.2 requires clarificatier as follows:

a) specifylthe magnitude of the negative pressure main-tained in the ECCS pump rooms durins normal operation and following a LOCA.

b) provide similar information for this system as requested in Question 6.106.

9 51 The description of the shield annulus recirculation and exhaust s;ste.a presented in GTSSAR'Section 9.4.5.3 req' tires clarification as follows:

i 9 51.1 Specify the marnitude of t're ne ative pressure maintained in the annulus during normal operation.

9 52.2 Describe the operation of_the system following a LoCA as-to the fractions of flow which are recirculated and exSausted to t' SGTS'and the negative pressures which are taintained.

9 5L3 Justify the adequacy of the system design considering the active failure of the valve in the recirculation line at the top'of the doce (Figure 9 4-5a).

.9 5L4 Provido nimilar information for this system as requested in Question 6.106.

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9 52 Chemical treatment of the closed coo 11n7 water system is discussed in Response 9 20.2 Modify Fi6ure 9.2-2a,b,or e to show how this is accomplished.

9.53 Page 9.4-2 states t' cat Figure 9 4-1 will. be ~ revised.. Fro-vide this ficure so that our review of.your response to question 9.30 can proceed. -

l 9 54 Incorporate the information siven in response to question 9 20.1 (concerning the design data of the major components of the closed cooling water system) into the applicable portions of GESSAR.

l 9 55 Response 9 20.3 states the heat exchan. ers for the fuel pool coolinc and cleanup s.ystem and the drywell. atmosphere cooling coils will not be cooled by the closed cooling etater (as shown in Figure 9.2-2d) but rather by the standby service water systen.

Clarify your position with respect to this item.

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