ML17341B187

Forwards Addl Info Re NUREG-0737,Item II.B.1, RCS Vents, in Response to NRC 820224 Request.One Oversize Drawing Encl. Aperture Card Is Available in PDR

ML17341B187
Person / Time
Site:	Turkey Point
Issue date:	05/26/1982
From:	Robert E. Uhrig FLORIDA POWER & LIGHT CO.
To:	Varga S Office of Nuclear Reactor Regulation
Shared Package
ML17341B189	List: ML17341B187 ML17341B190
References
RTR-NUREG-0737, RTR-NUREG-737, TASK-2.B.1, TASK-TM L-82-221, NUDOCS 8206010290
Download: ML17341B187 (37)

Text

r REGULATOR NFORMATION DISTRIBUTION . TEM (RIDS)

Zj AOCKSSION 'NBR"f 206010290 DOC DATE,'2/05/26 NOTARI'ZED: NO. DOCKET FAOIL:50- 50'rkey ~

Point Pl anti 'Uni t 3i Fl or ida Power and Light 'C 05000250 AUTH, NAME AUTHOR AFFILIATION UHRIGi 8 E, ~ F1 or ida Power 8 Light Co ~

IR BC I P ~ NAME RECIPIENT AFF ILIAT ION VARGAi A, S ~ Operating Reactors Branch 1

SUBJECT:

For wards addi into r e NUREG-0737i Item II B ~ ii "RCS Ventsi"

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in response 'to NRC 820229 request Three oversize drawings encl. Aperture cards are available in PDR.

~RACY) i@i4 W DISTRISUTION CODEI AOASS:COPIES RECEIVED:LTR,JENCL Q SIZEi i

(@+3 TITLE: Response to NUREG "0737/NUREG 0660 TMI Action Plan Rgmts (OL's)

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~ SW PiEASVae RECIPIENT ID CODE/NAME To, 4S COPIES Pic.8 LTTR ENCL br'C (i)RECIP IE/T ID CODE/NAME CZ) Sc~~

COPIES LT~TR ENCL ORB 01 BC 01 7 7 INTERNALS ELD/HDSO 1 0 IE/DEP 0IR 33 1 1 IE/DEP EPOS 1 1 IE/DEP/EPLB 3 3 NRR/DE DIR 21 1 1 NRR/DE/ADCSE 22 1 1 NRR/DE/ADMQE 23 1 1 NRR/DHFS D1R 28 1 1 NRR/DHFS/DEPY29 1 NRR/DL D I'R 10 1 1 NRR/DL/ADL 16 1 1 NRR/DL/ADOR 1'5 1 1 NRR/DL/ADSA 17 1 1 NRR/DL/DRAB 18 3 3 NRR/DSI DIR 2A 1 1 NRR/DS I/ADDPS25 1 1 NRR/DS I/ADRP 26 1 1 NRR/DS I/ADRS 27 1 NRR/DS I/AEB 1 1 NRR/DSI/ETSB 1 NRR/DS I/RAB 1 1 NRR/DST D IR 30 1 1 NRR 'GP 31 1 1 NRR/DST/ADT 32 1 G- 00 1 "1 RGN2 1 1 EXTiERNALo ACRS 3u 10 10 FEMA REP DI V 1 1 INPOiJ,STARNES 1 1 LPDR 03 1 1 NRC PDR 02 1 1 NSIC 05 1 1 NTIS 1 1 TOTAL NUMBER OF lCOPIES REQUIRED0 LTTR 53 ENCL '52

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FLORIDA POWER & LIGHT COMPANY May 26, 1982 L-82-221 f ti Of i ce of Nuc1 ear Reactor Regul a on Attention: Mr. Steven A. Varga, Chief Operating Reactors Branch gl Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Dear Mr. Varga:

Re: Turkey Point Units 3 8 4 Docket Nos. 50-250 and 50-251 Post-TMI Requirements NUREG-0737 Item I I.B. 1 Reactor Coolant S stem Vents Attached is the Florida Power and Lighh response to your February 24, 1982 letter which contained a request for additional information concerning the RCGVS at Turkey Point Units 3 and 4. We trust that our response will allow the staff to complete thei r revi ew.

Very truly your s, PuM Robert . Uhrig Vice President Advanced Systems 8 Technology REU/PKG/mbd cc: J.P. O'Reilly, Region II Harold F. Rei s, Esquire S

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ATTACHMENT Re: Turkey Point Units 3 Docket Nos. 50-250, 50-251 Pos+ TMI Requirements NUREG-0737 Item II.B.1 Reactor Coolant S stem Vents QUESTION l Verify that the reactor coolant gas vent system (RCGVS) flow xestriction oxifices are 'smaller than the size corresponding to the definition of a loss-of-coolant accident (10 CFR Part50, Appendix A) by providing the pertinent design parameters of the reactor coolant makeup systems and a calculation of the maximum rate of loss of reactor coolant through the RCGVS orifices (reference NUREG -0737 Item II.B.l Clarification A.(4)).

Response-The orifice used in the RCGV'S (7/32" x l") is the standard size orifice used throughout the C-E NSSS to limit mass loss from instrument line breaks to less than the makeup capacity of a single charging pump.

Initial conditions upstream of the orifice were consideredwith pxessures ranging from 1800 to 2250 psia at corresponding saturation temperatures to calculate the mass flow rate through the orifice. Under these con-ditions, the orifice will limit the mass loss to approximately 4 ibm/sec (29 gpm), which is w'ell within the capacity of a single charging pump (77 gpm).

J> 1

UESTION 2 The following items apply to the portions of the RCGVS that form a part of the reactor coolant pressure boundary, up to and including the second normally closed valve (reference NUREG-0737 Item II.B.l Clarification A.(7)).

Verify that the materials of. construction will be fabricated and tested in accordance with SRP Section 5.2.3, "Reactor Coolant Pressure Boundary Materials."

b. Demonstrate that internal missiles and the dynamic effects associated with the postulated rupture of piping will not prevent the essential operation of the RCGVS (i.e., at least one vent path remains functional) (reference Appendix A'o 10 CFR part 50, General Design Criterion 4).

RESPONSE

The RCGVS is a modification to the existing reactor vent, thus the change was performed in accordance with ASME Section XI. Therefore, the system was installed in accordance with the applicable PSAR committments in regard to the requirements of SRP Section 5.2.3. The components for the system were procured in accordance with SRP Section 5.2.3.

b. There are no postulated piping failures which would preclude the essential operation of the RCGVS. In the vicinity of the RCGVS there are no potential internal missiles or dynamic effects (pipe whip, jet impingement, etc.) that= would preclude the essential operation of the RCGVS. The high energy lines inside containment are not in close proximity to the RCGVS.

i+I UESTION 3 Since your submittal of July 16, 3.981 was based on the Combustion Engineering, generic RCGVS design., verify that your final piping configurations have been "reviewed or analyzed to assure their capability in maintaining the integrity of the piping system" (reference p.23 of your submittal).

RESPONSE

Attached. for your information is the stress report certificate for the piping stress analysis of Turkey Point Units 3 6 4 Reactor Head Vent System. Mhen the "final as-built" configurations of the, system are complete, the information will be transmitted to Combustion Engineering for final verification of the stress analysis. However, no maj or modifications of the system during installation is anticipated.

Ql 4 ~

Stress Report Certificate This is to certify that, in accordance with'SIDE Boiler and Pressure Vessel

.Code; Section III, Paragraph NA-3260, the following Stress Report has been reviewed and is based on the Design and Service Loadings stated in the De-

.sign Specification identified below.

Stress Report: Vendor: Nuclear Structures Inc.

Report: '002-08 Revision: 00 Date: 11-17-81 Design Specification f: 96480-PE-141 Revision: 02 Date: 10-21-81 Plant Owner: Flordia Power & Light (Turkey Point Units 3 5 4}

Designee: Combustion Engineering, Inc.

Power Systems Group Nuclear Power Systems .

Mindsor, Connecticut Certified by:

Approved by:

Name Title Date

i' UESTION 4 Verify that the following RCGVS failures have been analyzed. and found not,to prevent the essential operation of safety-related systems required for safe reactor shutdown or mitigation of the consequences of a design basis accident:

a0 Seismic failure of RCGVS components that are .not designed to withstand the safe shutdown earthquake.

b. Postulated missiles generated by failure of RCGVS components.

C~ Fluid sprays from RCGVS component failures. Sprays from normally unpressurized portions of the RCGVS that are Seismic Category 1 and Safety Class 1, 2, or 3 and have instrumentation for detection of leakage from upstream isolation valves need not be considered.

RESPONSE

a. The entire reactor coolant head vent system at Turkey Point Units 3 6, 4 will be seismically supported, thus this question is not applicable.

The normally closed isolation valves on the system which are the only components of the system which could generate a missile have been provided with backseats to,preclude a missile. In accordance with the Turkey Point Units 3 & 4 FSAR, Page 5E-5, valves provided with backseats do not have to be considered to generate internal missiles. Hence, the ability to achieve and .maintain a safe reactor shutdown is assured.

Ce The normally unpressurized portions of the reactor coolant head vent system are entirely Seismic Category I and Safety Class 1, 2 or 3'up to the second isolation valve, and have leak detection capabilities from upstream isolation valves.

Fluid spray from the normally pressurized portion of the RCS head was not considered in accordance with SRP 3.6.2, since the, pipe diameter is one inch or less.

Qi I

uestion 5 Describe the design features or administrative procedures, such as key locked closed val'ves or removal of power during operation, that will be employed to prevent inadvertent actuation of the RCGVS (reference iXUREG-0737 Item II.B.l Clarification A. (7)).

~RBS OllSL The RCGVS at Turkey Point utilizes key.:locked closed valves during operation, to prevent inadvertant actuation.

4~

UESTION 6 Demonstrate, using engineering drawings (including isometrics) and design descriptions as appropriate, that the RCGVS paths to the containment atmosphere (both direct and via the quanch tank rupture disc) discharge into areas:

a. That provide good mixing with containment air to prevent the accumulation or pocketing of high 'concentrations of, hydrogen, and

b. 'n whichshutdown any nearby structures, of the reactor systems, and components essential or mitigation of a design basis to safe accident are capable of ~ithstanding, the effects of the anticipated mixtures of steam, liquid, and noncondensible gas discharging from the RCGVS (reference NUREG-073'7 Item II.B.l Clarification A.(9)).

RESPONSE

The flow path to be used during post accident operation is the vent to the containment atmosphere. The flow path to the pressurizer relief tank is provided as an aid during the filling and venting of the reactor. Therefore, our response is limit'ed to the direct flow path to the containment.

The discharge point from the RCS vent is located at elevation 80'-0" (see Nuclear Structures, Inc. Drawing No. 2002-08-2, Rev. 0, Coordinates C-6). As can be seen on drawing 5610-M-60 and 5610-M-154 this discharge point is in an open area of the containment that is well suited'or mixing. There is no equipment or structure above the discharge point that could form pockets of high concentrations of hydrogen.

b. As can be seen on the same drawings referenced above, there is no safety related equipment in the area that would be affected by the discharge from the 'RCS vent.

Ol I

uestion 7

1. Submit operating guidelines for use of the RCGVS including the following:

a. Guidelines to determine when the operator should and should not manually initiate venting, and information and instrumentation required for this determination (reference NUREG-0737 Item II.B.1 Clarification A.(2)). The guidelines to determine whether or not to vent should cover a variety of reactor coolant system conditions (e.g., pressures and temperatures). The effect of the containment hydrogen concentration on the decision to vent or to continue venting should also be addressed considering the balance between the need for increased core cooling and decreased containment integrity due to elevated hydrogen levels.

b. Methods for determining the size and location of a noncondensible gas bubble (reference Position (2) and Clarification A.(2)).

c. Guidelines for operator use of the vents, including information and instrumentation available to the operator for initiating or terminating vent usage (reference Position (2)).

d. Required operator actions in the event of inadvertent opening, or failure to close after opening, of the vents including a description of the provisions and instrumentation necessary to detect and correct these fault- conditions (reference Position (2) and Clarification A (2)).

e. Methods which in lieu of venting will assure that sufficient liquid or steam will flow through the steam generator U-tube region so that decay heat can be effectively removed from the reactor coolant system (reference Clarification C.(2)).

~Res ense The Turkey Point nuclear Safety Committee has appr oved a new procedure (0P 1008.10, Response to .Voids in the Reactor Vessel) for the off-normal use of

. the reactor vessel head vent.

a. The procedure directs the operator to initiate venting when needed and to terminate when not needed or wnen adverse RCS conditions exist. The procedure allows use of the head vent system under a variety of RCS conditions. Hydrogen concentration in containment is addressed in the procedure and is one of the parameter prerequisites governing RCS venting.

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b. The procedure is primarily concerned with void formation in the reactor vessel and does not attempt to distinguish as to size and location of the non-condensible gas bubble.

c. The procedure offers adequate guidelines for operator use of the vents including. i nformation on instrumentation available to the operator for initiating and terminating vent usage.

d. The procedure does not address operator actions in the event of inadvertent openi ng or failure to close after opening. Uue to the fact that the RCGYS is equipped with key locks and because it utilizes double valve protection, ther e exi sts .more than adequate protection against inadvertent opening. The administrative procedural controls used in the procedure to prevent failure to close after opening are deemed adequate by the Turkey Point Plant Nuclear Safety Committee.

e. The procedure requi res the operator to attempt to repressurize the RCS prior to venting in an attempt to collapse any existing voids.

If this attempt and the head vent attempt fail,, the RCS parameters should exceed the limits stipulated in the procedure.. If this was the case, the operator is instructed to reinitiate safety injection to assure adequate core cooling.

A copy of procedure OP- 1008. 10 is enclosed for your information. The procedure was written utilizing, for the most part, the guidelines provided by the Westinghouse Owners Group.

Ql QUESTION 8 Verify that all displays (including alarms) and control's, added to the control room, as a result of the THI Action Plan requirement for reactor coolant system vents, have been or will be considered in the human factors analysis required by NUREG-0737 Item X.D. I, "Control-Room Design Reviews."

RESPONSE

All displays and controls, added to the Control Room as a result of the TMI Action Plan requirement for reactor coolant system vents are being considered in the human factors analysis .required by NUREG-0787, Item I.D-l, "Control Room Design Reviews."

I '

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RIDA POWER AND LIGHT CQHPA.'IY TURKEY POINT UiHTS 3 P~iD 4 OFF-NOR"1AL OPERATING PROCiDL~v 1008 10 APRIL 29, 1982

1.0 Title

RESPONSE TO VOID IN REACTOR VESSEL 2.0 Approval and List of Effective Pages:

2.1 ~Ao revel:

Reviewed by Plant Nuclear Safety Committee: 82-42 Approved by Plant ~iwnager-Nuclear. 4/29!82

2. 2 Lis t o f Ef fective Pages:

~Pa e Date ~Pa e Date Page 1 4/29/82 3 4/29/82 5' 4/29/82 2 4/29/82 4 4/29/82 "

4/29/82 7 4/29/82 3.0 Purnose and Discussion:

3. 1 cirrose 3 This procedure provides instructions when a void is detected in the reactor vessel and when the operator determines that it should be removed.

3.2 Discussion; 3.2.1 Any number of transients can result in a void, whenever saturation conditions exist in the vessel head, or gas 's infected into or generated in th RCS.

3.2.2 Removal of a void in the reactor vessel should not be at tempted until a stable, subcooled RCS exists.

3.2.3 This procedure describes steps to remove the void. An initial attempt is made to condense the void. Th's attempt will ultimately succeed if the void is steam. I the void is gaseous, a head vent operation must be performed to remove the void.

4. 0 ~gross:

4.1 Variations from the normal pressurizer pressure and level response due to no. al charging and sparying op rations my be observed the RCS.

if a void exists in The pressurizer level may decrease during charging due to void contraction and level may rise rapidly during a spraying operation due to a void expansion.

4.2 Gases in the reactor coolant system ay result from several types of plant event"-. An accumulator d'scharge or a core uncovery may result in non-condensible gases being trapped in the RCS.

4.3 A rapid RCS cooldown may resul t in the'essel h ad temperature being greater than the primary saturation temperature and result in a steam bubble being developed.

NOTS: The of the operator should suspect tha above events occar.

p= eence oi gases ln the RCS li any

4/29/02 OFF-lClIHAL OMUTING PBDQ3XIRE IOOS. IO, PAtZ 2 RESIYNSE 'IO tJom TH RIMCIOR VL'SSEL me ACTIN/Iniycrm RESmm RFSIOIKE MÃ OKATNH) 5.0 Instruct hms:

5.1 Xaucdfate kutanatf c Acting None 5.2 Tnaedfate rator P~: thne 5.3 Sh Actfona:

C h U T I 0 N: EO IXX stop a~ running RCP's or start any stopped RCP's until carpletion of tld.s pmcedure 5.3.f Rcaad RCS Praaure: ~dg 5.3.2 Rx9Xy SZ 9ystea SIC TM OPBKfflH IF ST systan is in oImration, 'HRB go to Step 5.3.9.

5.3.3 (bede Stab1e P,CS Gmditioos:

a. Presamizer Level STABLE HEMPEN 4'nd 6CC a. Krually adjust letdown ~d cImrgfrg.

b. RCS Presaxre h&URZ b. Operate liters ard @ray

c. RCS Ibt Leg Teaperature SfAEfZ C. Ad)ust GtCQGL dOlp.

5.3.4 Try to Collapse Void in Reactor Vessel 2'.

a. Turn on pressurizer heaters to increase pressure by 50 psf o

b. Hdntain Manced cIerging md letdown flow.

c. Ihfntafn pressurizer level G~ 'HIAN TF level less tlen Step 5.3.3.

20X, %Kl turn off pressurizer heaters P2Q return to

II 4/29/82 OFF~V OiHKfigl BSCGNRE 1008.10, PhCH 3 RLSfQSE 'IO IOm IH REACfA? VIA%i Sm -uyralhXPEClm RES>em BESIM% NZ OBTAINED 5.3.5 Vm1fy VMd fblIapm in Reactor Vessel:

a. Pressurizer level clunges in the direction and at a rate a. IF level clmnges indicate that the void hao not oollapoed, go to corre~fng to RCS l43ter inventory balanceo Step 5.3.6.

(1) Men cl~rgfng plus oeal in)ectfon exceeds letdown plus oeM leakoff, presmrizer level deuld in"reaoe at a rate equivalent to the inventory df fference.

(2) Men chargfng plus oml injection are less than letdown plus oeal leakoff, presairfzer level dmuld deem".oe at a rate equivalent to th invaCory difference. ~

(3) pressurizer spr y operation slxuld not affect presmrf zer level.

b. Return to procedures in effect.

5.3$ Isolate Iotckan 5.3.7 Qmk Pressurizer Gondftions

a. Presmrf zer Level GKQ1?R 'JH"f HE a. Increase clmrgfng floe. IF level ca+mt be maintained above antisun chargfng, llR4 m~~ly ini.tiate SI ad go to EW; lm'ith Step 5.1.

b. Presasrfzer Level REDKBl 2CX and 9QX b. Aliquot cl urging flo~.

c. RCS Presmre GKGHt 11%1 OR RQM. '10 HlESRM~ c. Energfze liters. IF p'resmre decreasing in an unawtrolled BKXRM) IN Sf' 3.1 muuw.r, 'HRN annually inftiate SI ard go to EW, Step 5.1.

N 0 T E: Venting of the RPV may result in RCS presmre decreasfng belm SI initiation setlmfnt.

4(29/82 OI'F~V OKRATPG KOCEIXmE 1008.10, PAlZ 4 RESmm ID VOID IW I enOI VESSEI.

SIIP ACfIC+B{I'ECKDRESIDlSE Rale N0r aITAmm 5.3.8 (heck Iov Pressure@ Measure & Sigil Status:

a. Pressurizer Pressure SI SIgnal EUXXED a. KraLslly block.

5.3.9 Q~ RCS Rdxualirg=

a. RCS Subcooling QIEKIIR MINI 80 P a. IP less elan 80 'F, Vlf'ncrease steam hxnp. IP 80 'F subcoolirg camme be obtained, 'HIBl jo eo E-O, Step 5.1.

5.3.10 ~are QmtaIramt for Reactor easel Venting:

a. Source (heck R-ll or R-12 and Verify Contaiamnt Ventilation Isolation:

(1) CV~-2819 Cont. Instnaent Air Bleed mSED (2) CV~2826 Cont. Instnma>t Air Bleed QQSH)

(3) NN~-2600 Cont. urge Air Ripply Isol. QlÃED (4) HN~2601 Cont. leery. Air Supply Isol. QUASH)

(5) K@~2602 Cont. urge Atr Shet Isol. (XQK)

(6) ~-2603 (bne. erg Air EdLsust Isol. QIANA)

(7) 1'AN ~V 9 Cont. Vent Supply IRII'iM (8) FAN *-V20 Cone. Vent EdunLst XIII'ILD

b. Start Contaiarant Afr (Xrculation Fquiprent:

(I) Start all operable ?brmal Contaiamnt (bolers (2) Start all operable HrerI~cy Contaiarmt Coolers (3) Start all operable Bnergency Containment Filters

Ql II,

4/29/82 QV~~SI. 0)IIIATBG HSQQXRIE 1008.10, PAlZ 5 RESMM T0 VOID IH RFACKR VESSEI.

RESIGN NOf QlTATRB 5.3.11 Ihtendne Ihxtaaza All~bio Venting Ihtiod:

a. Contairmant lgdmgul Concentration - IEiS 'IIIAN 3Z

b. Calculate Ihximm Venting Rriod:

(See Graph cn Page 7 )

C A,U T I0 H & ANY vent tennlnation criterion jn Step 5 3 12 is reacIRB or exceeded Qlile ventingy IBHSNAIHYB'top venting 5.3.12 Ihvtaz RPV Vent 'lhnuination Criteria:

a. Contafnaent ligdmgen ConcentratiuHRKKIIR '1IRM 3X IIY MIIHE

b. RCS Kbcooling IXSS 'IINI Xl F

c. Pr~~rizer leal IZSS 'IIIAM 3X

d. HCS Pressure MRP~S IIY 200 PSI

e. 'enting Period QKZQR llNlImHO CAURIA'IH) IH SIEP 5.3.11 5.3.13 Ant actor Vial

a. ~ Vent Valves to Containrant: a. ~n Vent Valves to M'.

(I) ~x 6318A or 63188 (I) Jan 6318A or 63188 (2) Cpen 6320B (2) q 63m

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4/29/02 OFF-1m'. OmlAVaC WXmau. 1OOS.10, Pml 6 tuxmSZ m urn IN RF me mob Sly'Cl'HN/HPcCKO RESIGNS RISI&gLr lCI'E1'AINH) 5.3.13 (cont 'd)

b. Clom Vent Valves Nun:

(1) Presmrizer 1evel reqxxds in a nornal manner as described in Step 5.3.5.b OR (2) Any tenafnatica criterion of Step 5.3.12 is reached.

c.

5.3.12, ~

IF venting stopped becaua. of PXC criterion in Step return to Step 5.3.7.

5.3.14 Osedc Presaadzer Level SEARS Ad+at ingecticn aal letcka;n, as taquired.

5.3.15 Return to Procedure In Effect 6.0

References:

6.1 Meath')aua. Punctionnl hnvery Qxidelira (%7~) Basic dated S~tudjer 1, 190l.

6.2 ~xy Prccakce 2NXO (EW), ~~ Acticna ard ~~ca 7.0 iiunls mrts md Notifications; 7.1 leg Entries 7.2 Voids in tbe reactor Msa'1 may be reportable oca~s or algnlficant evens, or cay require initiatigg tlat Rheg~xy Plan. '?la Qxxctlons %pe~isa' >bchar, Opcratiom SUperinbxrknt kbdcar or Phyla Huv~ 143aar, @auld be rotlfied as +em aa poedble.

~i ONOP 1008.10

,~

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.Page j 4/29/82 A ~ Containment,Volume (at STP),

6 2250= (1.55 x 10 Ft ) x 4 92 R Cont. emp. F + CO 8 Haximum H Volume to be Vented 2

(3.0 - Present Cont H Concntration)x A 100~~

2000 o 1750 1500-1250 1000 r',

C I 1 2

~O V

4I~

C4 750 n

500 200 500 750 1000 1250 1500 1750 20 0 C ~ HYDROGEN F2 GW RATE (SCFM)