ML18019A393

Advises That,Following Evaluation Re Superheat After Postulated Main Steam Line Break Outside Containment Bldg, Superheat Not Safety Issue.Basis for Conclusion Presented to NRC on 850719

ML18019A393
Person / Time
Site:	Harris
Issue date:	09/23/1985
From:	Cutter A CAROLINA POWER & LIGHT CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
References
NLS-85-234, NUDOCS 8509300118
Download: ML18019A393 (38)

Text

n ~

REG TORY INFORMATION DISTRIBU N SYSTEM (RIDS)

ACCESSION'BR;8509300118 DOC ~ DATEE 85/09/23 NOTARIZED: NO DOCKET FACIL:50 400 Shearon Harris Nuclear Power Planti Unit 1> Carolina-BYNAME, 05000400 AUTH AUTHOR AFFILIATION CUTTER,A ~ B ~ Carolina. Power 8 Light Co.

RECIP NAME'ECIPIENT AFFILIATION DKNTON~H,R ~ Office of Nuclear Reactor- Regulationr Dir ector

SUBJECT:

Advises that~ fol lowing, evaluation r e. superheat af ter postulated main steam line. break outside containmentbldg<

superheat not safety issue, basis for conclusion presented to NRC on<<850719 ~

DISTRISUTIOR CODE: SDOID,COPIES RECEIVEDILTR TITLE.'icensing Submittal: PSAR/FSAR Amdts 8, Related Correspondence!

L ENCI. L" SiZE:

NOTES:

RECIPIENT GOPIKS RECIPIENT'D COPIES ID CODE/NAME> LTTR ENCL>> CODE/NAME- LTTR ENCL NRR/DL/ADL 1 0 NRR LB3 BC 1 0 NRR LB3 LA 1 0 BUCKLKY,B 01 1 1 INTERNALS ACRS 41>> 6 ADM/LFMB 1 0 KLD/HDS1 1 0 IE FILE. 1 1 IE/OEPKR/EPB 36" 1 IE/DQAVT/QAB21 1 1 NRR ROEgMNL 1 1 NRR/DE/AEAB 1 0 NRR/DE/CEB 11 1 NRR/OE/EHEB 1 1 NRR/DE/EQO 13I 2 NRR/DE/GB 28 2 2 NRR/DE/MEB 18 1 1 NRR/DE/MTEB 17 1 1 NRR/DE/SAB 24 1 NRR/DE/SGEB 25 1 1 NRR/DHFS/HFEB40. 1 NRR/DHFS/LQB 32 fv f>>

NRR/DHFS/PSRBI 1 NRR/DI./SSPB 1 0 NRR/DSI/AKB 26 1 1 NRR/DS I/ASB 1 1 NRR/Ds1/CPS 10, 1 1 NRR/OS I/CSB 09 1 1 NRR/DSI/ICSB 16" li 1 NRR/DSI/METB 1 NRR/DS I/PSB 19 li 1 12'AB 22 1 NRR/DS1/RSB 23i 1 1 RK K 04 1 1 RGN2 3 M/DDAMI/MI8 1 0, EXTERNAL 24X 1 BNL(AMDTS ONLY) 1 1 OMB/DSS (AMDTS) 1 LPDR 03 1 1 NRC PDR 0?! 1 1 NSIC 05 1 PNLI GRUEL'gR 1 1 1'OTAI NUMBER'F COPIES'EQUIRED ~ 'TTR 52'NCL

'111 1 li w

.47 4)" 4>>w44>>H>>X 5; ) 1 >>44". )', 4. 4 r 1 ~ g<<f fv 1>>w 4 g "f , )n f') 4 1'h>> w

',<> w w<<

~ >><< .>> '1 >>4 f rf ~ ~ I e

I Hh ) ') I j) qiw I w

~

<<') )

I'I'1 f 4 40 f'hw f H>>4 '1 "')Hv ) -)hv'4 whh )(<< <<4<<>>; h'1 (1<<;I f jl fh>>) t hwy tint>>>>f ) (tw fvw x t !>>HI) ') 4'IO ~" >> f f ('>>) '4 P fl, 4>> <<<<1 thh '1'(ll >>1Q f >>'4>> l 1 'II4 1

~ '1>>h ) 4(h , >>4)..>> f jv r>> i>> 'll' 1 1

~,4, QT>>, 5> II ) )<<1 3

I 4 1

") )I 4 , f ii .I 'f ~ T v;',

<<Ig v<<)h~vh>> )fhl9 >>) << f>>rf<<>>4 (4 ~ t 41>> 4<<, ( o l<<1) P (,H )v ~ >>I f

~ il ~

[ ') J, ') J l>>

r.

'ft I $ Ihl II'i', 3 f

'i, Ji t

)f J >>

HP 4 i<< ",4," "5)

R Zl 4 vi fk ('4i ~ i<) )X H

~'H,j 4 1>>ll 1'),

<<>> )H)'<<4 k I X hvhh g<<)," r <<l 'I'wi

~ .41 .

44 v")~ )Pvu<<

,,r H << f ), 1 4)

' ', '4H 'Sl v<<41% ( kh<<)I>>I<<1 4

41 'w 1<<'>>i<< w

'v>>

lx 'l

()'3 4't A) j>>'i i 1) X

>>74.

4 $ 1<< j 4)HV, l 1>> h

) 4 t <<4 f 1 4>> 1",f 1

CM6 Carolina Power & Light Company SERIAL: NLS-85-230 PEP 3 31985 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation United States Nuclear Regulatory Commission Washington, DC 20555 SHEARON HARRIS NUCLEAR POWER PLANT - UNIT NO. 1 SHNPP DOCKET.50-000 MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT

Dear Mr. Denton:

Carolina Power k Light Company (CPRL) has completed its evaluation related to superheat following a postulated main steam line break outside of the containment building. The Company has concluded superheat is not a safety issue for the Shearon Harris Nuclear Power Plant (SHNPP).

The basis for this conclusion was presented to members of your staff on 3uly 19, 1985.

Carolina Power R Light Company demonstrated that the actual piping design stresses are only a small fraction of the NRC allowables. This large margin does not include the many conservatisms in the pipe stress calculation codes, and the inherent conservations added by water chemistry control and actual system operating pressures. Irrespective of the conclusion that superheat is not a credible concern, CPRL considered the effects of superheat and concluded these effects are bounded by existing design conditions. The steam tunnel size and venting area limit the steady state transient pressure buildup to less than 1 psi above atmospheric pressure. This prevents the condensing film temperatures on components and structures from exceeding 215'F. Consideration of the heat transfer effects shows the bulk temperature in the tunnel will not exceed design limits and equipment temperatures will not exceed their qualification envelopes.

Additionally, equipment that is essential for safe shutdown following a break actuates to its required position before the bulk air temperature exceeds the equipment qualification temperatures.

The NRC staff concurred with CPRL's evaluation contingent upon clarification of two items. The NRC staff also required that an arbitrary break be postulated regardless of the available margins in pipe stresses. The information presented in the 3uly 19, 1985 meeting is attached for your use as Enclosure 1. The Meeting Attendees List is attached as Enclosure 2.

The first point of clarification requested was an explanation of why the Harris steam tunnel temperature increased to approximately the same temperature as relatively smaller compartments reviewed by the NRC.

The Harris steam tunnel subcompartments, as well as the other are small compared to the volume of steam being released from a plants'ubcompartments, postulated break. As a result, essentially the entire pre-break atmosphere is swept from the compartment, and the compartment bulk ambient temperature will approximate that of the released steam.

411 Fayettevitte Street o P. O. Box 1551 ~ Raleigh, N. C. 27602

0 C'

~ ~

Mr. Harold R. De Nk.S-85-230 / Page The second point of clarification requested was a discussion on the applicability of using the Westinghouse Owners'roup generic data (reference data) for a Harris specific application.

Carolina Power A Light has completed an assessment of Harris versus the reference plant and determined the reference data is bounding for a Harris specific application. This assessment includes a comparison of pertinent plant parameters and a discussion of hoiv these parameters behave during steam line break.

COMPARISON OF PERTINENT PLANT PARAMETERS The reference plant has more energy stored in the primary system as:

a. sensible heat (with four loops instead of three; this is due to the specific heat of additional metal and primary coolant), and

b. decay heat.

2. The two plants have practically the same steam generators (SG) - (both are Westinghouse Model D preheat steam generators).

3. Although the reference plant's total Auxiliary Feedwater (AFW) flow is higher than SHNPP, the proportional amount fed to each steam generator for the reference plant is lower.

With a rated power of 3027 MWth, the reference plant has 2000 gpm divided among four SGs; 0.106 gpm per MWth per SG.

With 2785 MWth, SHNPP has 1800 gpm divided among three SGs or 0.215 gpm per MWth per SG. This is an increase in flow of -07 percent per MWth for each SG.

DISCUSSION Two cases are considered:

1; Breaks that initiate MSIV closure In the short amount of time before MSIV closure is accomplished, the temperature and enthalpy of the blowdown will be essentially the same for the two plants as the integral flow restrictor controls the choked flow.

After the SGs are isolated, the MSIV design function is completed and the success criteria is achieved.

2. Breaks (smaller) that do not initiate MSIV closure

a. The relatively larger AFW flowrate (-07 percent more per MWth) for each SG at SHNPP can maintain a level in the SG shell covering the tube bundle for larger break flowrates than at the reference plant. Keeping the tube bundle covered precludes superheating of the steam.

e ty

~l

'i *~

Mr. Harold R. De~

NLS-85-230 / Page&

b. The remaining situation is break flow low enough to avoid initiating MSIV closure (and AFW isolation), but large enough to prevent AFW from maintaining secondary side level. If level cannot be maintained, the higher relative AFW at SHNPP translates to a higher steam flow rate. As with any convective heat transfer configuration, the larger flowrate of steam up past uncovered tubes gives less of a temperature rise (superheat) in the steam for SHNPP.

In either situation, the temperature and specific enthalpy of the steam entering the subcompartment at SHNPP will be bounded by (i.e., less than, or equal to) that at the reference plant.

The information in Enclosure 3, when used with the Westinghouse Owners'roup blowdown data, provides sufficient information for an independent assessment of the steam blowdown transient into the main steam tunnel.

This submittal concludes CP&L's assessment of superheat outside containment. Thus, CPRL considers this issue resolved with the NRC staff.

If you have any questions, please call.

Your ery tr A. B. Cutter - Vice sident Nuclear Engineering 2 Licensing ABC/DCM/ccc (1663DCM)

Enclosures CC: Mr. B. C. Buckley (NRC) Mr. 3. P. Knight Mr. G. F. Maxwell (NRC-SHNPP) Mr. L. S. Rubenstein Dr. 3. Nelson Grace (NRC-RII) Mr. 3ohn D. Runkle Mr. Travis Payne (KUDZU) Dr. Richard D. Wilson Mr. Daniel F. Read (CHANGE/ELP) Mr. G. O. Bright (ASLB)

Wake County Public Library Dr. 3. H. Carpenter (ASLB)

Mr. Wells Eddlernan Mr. 3. L. Kelley (ASLB)

ENCLOSURE I PURPOSE:

TO REVIEIN THE DESIGN BASIS FOR THE CURRENT MAIN STEAM TUNNELs

~ TO DISCUSS THE EXISTING CONSERVATISMS IN THE MAIN STEAM TUNNEL DESIGNs

~ EXPLAIN WHY THERE IS NO BASIS OR ADDED CONSERVATISM IN POSTULATING AND ANALYZING NEW CRITERIA FOR AN ARBITRARY CONDITION ~

(17300CM/ccc )

Page 1 of 21

BACKGROUND:

EVOLUTION OF HSLB OUTSIDE CONTAINMENT AT SHNPP DATE JuNE 1971 CPRL DOCKETED HARRIS PSAR FOR CP.

JuLY 1977 NRC ISSUED SUPPLEMENT 3 TO THE CP SER ACCEPTING THE HARRIS SUPER PIPE WITHOUT RUPTURE ~

JANUARY 1978 HARRIS CP WAS ISSUED.

APRIt 1978 NRC LETTER TO CP8L REQUESTING STEAM TUNNEL BE DESIGNED FOR PRESSURE AND ENVIRONMENTAL EFFECTS OF A LARGE HAIN STEAM LINE BREAKS JuNE 1978 CP8L LETTER TO NRC DECLARING THIS NEW CRITERIA TO BE A SIGNIFICANT BACKFIT AS DEFINED IN 10 CFR 50.109.

JUNE 1978 CPRL AND NRC MET TO DISCUSS NEM CRITERIA.

JULY 1978 CPRI COMMITTED TO POSTULATE A NON-MECHANIST I C BREAK FOR PRESSURE AND TEMPERATURE EFFECTS BUT NO DYNAMIC EFFECTSI AUGUST 1978 EBASCO/CPRL MADE MAJOR CHANGES TO THE TUNNEL JUNE 1979 'TRUCTURAL DESIGNS 1981 EBASCO/CPRL UTILIZED THE HASS ENERGY BLOWDOWN DATA OF NRC APPROVED NCAP 8822 FOR THE HARRIS STEAM TUNNEL ANALYSIS.

(1730DCM/ccc )

Page 2 of 21

BACKGROUND: (CONT D)

DATE NOVEMBER 1983 OL SER APPROVED CP8L'S STEAM TUNNEL DESIGN.

JUNE 1984 WESTINGHOUSE INfORMS CUSTOMERS OF POTENTIAL FOR SUPER-HEAT ~

JULY 1984 CP8L DETERMINES SUPER-HEAT ISSUE DOES NOT APPLY TO HARRIS SUPER PIPE.

pe (1730DCM/ccc )

Page 3 of 21

I

'l I

I 4

SHEARON HARRES NUCLEAR POWER PLANT CAROLINA PGNER & LIGHT COMPANY MAIN STEAM TUNNEL CK I

I I

44 t)i r I I r 0

.r t ro t

J page 4 of 21

,I I

IL

l~ I

= i%I 1 0 0 II~II I

~ THE DESIGN BASIS OF THE STEAM TUNNEL PIPING IS THAT THE PIPE DOES NOT RUPTUREs

~ THERE IS NO BASIS TO POSTUI ATE A RUPTURE SINCE THE PIPE STRESSES ARE MAINTAINED MELL BELOM THE NRC S BREAK EXCLUSION ZONE DES I GN CRITERIA s

~ ADDiTIONAL CONSERVATISMS'AVE BEEN INCORPORATED INTO THE HARRIS DESIGN BY THE POSTULATION OF A CPRL/NRC NEGOTIATED ENV I RONMENT e

~ CPRI HAS QUALIFIED ESSENTIAL COMPONENTS IN THE STEAM TUNNEL

,TO THE NEGOTIATED ARBITRARY ENVIRONMENTI

~ 'PERFORMING ADDITIONAL ANALYSIS DOES NOT SERVE TO

,INCREASE THE PUBLIC SAFETY (17300CH/ccc) page 6 of 21

SHEARON HARRIS NUCLEAR POMER PLANT CAROLINA POMER 8, LIGHT COMPANY CONSERVATISMS BEYOND DESIGN BASIS

~ ACTUAL CALCULATED PIPE STRESSES ARE A SMALL FRACTION (e05 TO

.02) OF THE NRC ACCEPTANCE CRITERIA.

~ ACTUAL MATERIAL PROPERTIES OF THE MSP TAKEN FROM THE CMTR DATA SHOW THAT YIELD STRESS OF THE PIPE USED AT HARRIS TO BE 15X ABOVE THE ASME CODE ALLOWABLE' PIPING WELDS HAVE BEEN RADIOGRAPHED PER ASME CLASS 2 AND B 3lal CRITICAL SYSTEM CONSTRUCTION EXAMINATION REQUIREMENTS ~

~ STRAIGHT PIPING IS EXTRUDED AND THEREFORE SEAMLESS. THIS MAKES THE POSSIBILITY OF A LONGITUDINAL BREAK EVEN MORE REMOTEs

~ PSI PROGRAM IS TO PERFORM A 100X VOLUMETRIC INSPECTION OF ALL WELDS IN THE BREAK EXCLUSION ZONE ~

~ ISI PROGRAM IS TO PERFORM A 100'OLUMETRIC OF ALL WELDS AT EVERY ASME SECTION XI INSPECTION INTERVALs (1730DCM/ccc )

Page 7 of 21

Summary of Break Exclusion Stresses Main Steam Line 50 Harr is Pipe Yield Str ess - 46.7 45 Code Yield Stress Allowable 40.0 40 HRC Oper atinq Condition 37. 8 35 3O T

9 25 20- tanto/naant Panatr'ation Pipe Str ess " Oper atin9 Condition 10 alia Valvaa V V SN>

Y Nodel Node Points

SHEARON HARRIS NUCLEAR POttER PLANT CAROLINA PONER R LIGHT COMPANY OTHER INHERENT CONSERVATISMS IN THE DESIGN AND OPERATION OF THE SYSTEM

~ CONSERVATISMS IN THE PIPE STRESS CODE USED TO CALCULATE SHNPP ACTUAL PIPE STRESSESs

~ CHEMISTRY CONTROL OF SECONDARY SIDE MATER TO ENHANCE S/G RELIABILITY' OTHER DESIGN AND OPERATIONAL CONSIDERATIONS'1730DCM/ccc

)

Page 9 of 21

SHEARON HARRIS NUCLEAR POMER PLANT CAROLINA POMER 8 LIGHT COMPANY INHERENT CONSERVATISMS IN THE PIPE STRESS ANALYSIS

~ ENVELOPED RESPONSE SPECTRAL

~ LOW DAMPING VALUES ~

~ LEFT OUT FORCE FOR RIGID MODE CONSIDERATIONe

~ PEAK SPREADING OF RESPONSE SPECTRAL ABSOLUTE SUMMATION FOR CLOSELY SPACED MODEST

~ DECOUPLING OF PIPING AND STRUCTUREe

~ SPECTRAL PEAKS AND SEISMIC DISPLACEMENTS ARE ASSUMED TO OCCUR AT THE SAME TIME ~

(1730DCM/ccc )

Page 10 of 21

SHEARON HARRIS NUCLEAR POMER PLANT CAROLINA POWER 8, LIGHT COMPANY INHERENT CONSERVATISMS IN MATER CHEMISTRY CONTROL

~ NON-SUSCEPTIBILITIES TO CORROSION CRACKING FOR FERRITIC TYPE CARBON STEELe

~ PIPING IS CLEANED EXTERNALLY AND FLUSHED WITH DEMINERALIZED WATER AS, PART OF THE PRE-OPERATIONAL TEST PROGRAMe

~ HATER CHEMISTRY FOR PRE-OPERATIONAL TESTING IS CONTROLLEDe DURING PLANT OPERATION> SECONDARY SIDE WATER CHEMISTRY WILL BE MONITOREDe CONTAMINATE CONCENTRATIONS WILL BE KEPT BELOW THE THRESHOLDS KNOWN TO BE CONDUCIVE TO STRESS CORROSION CRACKING.

(1730DCM/ccc )

Page ll of 21

SHEARON HARRIS NUCLEAR POMER PLANT CAROLINA POWER R LIGHT COMPANY OTHER DESIGN AND OPERATION CONSIDERATIONS

~ CYCLIC THERMAL STRESSING OF THE PIPING SYSTEM IS MINIMIZED DURING NORMAL PLANT OPERATIONe

~ HINIMIZE TRANSIENT AND STEADY STATE VIBRATION BY CONSIDERING SUCH EFFECTS IN THE PIPING AND PIPE SUPPORT DESIGN CONFIGURATIONS' HAIN STEAM PIPING AND SUPPORTS HAVE BEEN DESIGNED TO ACCOMMODATE THE RESULTING LOADINGS ASSOCIATED WITH STEAM HAMMER AND SAFETY RELIEF VALVE DISCHARGE LOADS' HINIMIZE PIPING LOCAL STRESSES FROM WELDED ATTACHMENTS BY MINIMIZING THE USE OF THESE ATTACHMENTSs

~ STEAM PRESSURES AT OPERATING CONDITIONS ARE LESS THAN THEY ARE AT NO LOAD AND ISOLATED CONDITIONS (- 965 PSIG AT FULL POWER VS ~ 1185 PSIG AT RELIEF VALVE SETPOINT) a (1730DCH/ccc )

Page 12 of 21

CONCLUSION

~ PIPE STRESSES IN THE BREAK EXCLUSION ZONE ARE A SHALL

=

FRACTION OF ALLOWABLE' HARRIS DESIGN BASIS IS TO MAINTAIN PIPE STRESSES BELOW THE NRC ALLOWABLES FOR PIPE BREAK CONSIDERATIONs

~ CPRL AND THE NRC NEGOTIATED AN ARBITRARY ENVIRONMENT IN 1978 FOR PRESSURE AND TEMPERATURE EFFECTS WITHIN THE TUNNEL EVEN THOUGH SUPER PIPE DOES NOT RUPTUREs

~ CP8L HAS RE-DESIGNED THE TUNNEL AND QUALIFIED ESSENTIAL EQUIPMENT WITHIN THE TUNNEL TO THE NEGOTIATED ARBITRARY ENV I RONHENT ~

~ THERE IS NO BENEFIT TO THE HEALTH AND SAFETY OF THE PUBLIC BY POSTULATING A NEW ARBITRARY ENVIRONHENTs (l7300CM/ccc)

Page 13 of 21

SUPER-HEATED STEAM

~ .NEWLY PROPOSED SUPER-HEAT CONDITIONS IN THE TUNNEL ARE OF A SHORT DURATION ORDER OF MINUTES AND ARE NOT EXPECTED TO VIOLATE THE EXISTING QUALIFICATION ENVELOPEN

~ CURRENT RfSEARCH ON 6ENERIC TASK A-21. MAIN STEAM LINE BREAK INSIDE CONTAINMENT'ONCLUDED THAT BECAUSf OF RELATIVELY LOW HEAT TRANSFER RATE IN SUPER-HEATED STEAM AND THE HEAT CAPACITY OF THE AFFECTED SAFETY-RELATED EQUIPMENT> THE fQUIPMENT ITSELF WOULD NOT BE EXPECTED TO EXCEED THE TEMPERATURE FOR WHICH IT WAS QUALIFIED AS A RESULT OF THIS SHORT DURATION PEAK IN THE TEMPERATURE OF THE CONTAINMENT ATMOSPHERfa

~ PEAK TEMPERATURES OF THE CONDENSING FILM ON fQUIPMENT IN THE VENTED MAIN STEAM TUNNEL OUTSIDE CONTAINMENT WOULD BE LESS SEVERE THAN A PRESSURIZED CONTAINMENT FOLLOWING A HELB.

(1730DCH/ccc)

Page 14 of 21

Steam Tunnel Bulk Air Temperature Response 500 1..4 8q ft MSLB 400 T

Generic super heat COMPARE data P

--- (estimated) r F a p Selected Points 300 \\ with revapor ization U

r EQ Envelope II 100 50 100 1 0 Time (seconds)

380 TRANSMITTER 5 CABLE QUALIF)CAT)ON TEST TEMPERATURE K

~

g280 K

~ ~

I 220

~

f'~ <<0 ~ ~ O~ J~

~ ~ ~ 'P~

/

f.r

. ~

180

/.A LEGEND:

CABLE SURFACE TEMP

~ ~ ~~ CABLE TEMP .045" BELOW SURFACE

~

~ i ~~~ TRANSMITTER SURFACE TEMP

/

o ~

~

100 0 60 120 TIME (SECONDS)

SHEARON HARRIS FIGURE NUCLEAR POWER PLANT TYPICAL Carolina EQUIPMENT TEMP. VS. TIME Power 5 Light Company WORST CASE A2 age of 21

JACKET ICtEI SHIELD TAtE LOel "I INSULATION IF REFI CottER CONDUCTOR CottE R ~ ~ ~ +

DRAIN WIRE IG ROUND)

OVERALL DIAM. ~ ~ INCHES TYPICAL ELECTRIC INSTRUMENTATION CABLE 4S/4" MAX. 4 1/E" MAIL 3/a" CLEARANCE FOR COVER REMOVALITYFICALI 1/E'la NFT CONDUIT CONNECTION NAMEFLATE TR ANSMITTER CIRCUITRY THIS SIDE TERMINAL 7/I CEO UNF CONNECTIONS THIS SIDE ITYtl CALI VENT/DRAIN

~ VALVE rI g

't HL 7/16 la UNC Ia tLAcEsl 1/41) NFT tRESSURE CONNECTION lTYtICAU TYPICAL TRANSMITTER SHEARON HARRIS FIGURE NUCLEAR POWER PLANT Carolina TYPICAL COMPONENT DIAGRAMS A-1 Power 5 Light Company Page l7 of 21

Q Z

ocn rZ fTl m A 200

~o 5'o m

O 37~

175 150 a O U b O O O O

OOO OO O 125 O

I mA Ol

~~ 100 Q

H-I O>

C 2 m 75 2'm 07 ill ~

~

~

m I- DETECTOR LOCATIONS CD mQ I % 0~ ADJACENT TO JUNCTION BOX EXTERIOR CQ ~~ 6 ~ JUNCTION BOX INTERIOR yO ~ ON CONNECTOR SURFACE f

25 0

0 10 20 30 40 50 60 70 80 90 10D 11D 120 130 140 150 160 170 180 190 200 210 ELAPSED TIME.MINUTES

HEAT SINK INTERIOR SINK SURFACE CONOEiVSATE BOUNDARY I

.LAYER J LIQUID-GAS INTERFACE GASEOUS BOUNDARY LAYER BULK CONTA INMEiVT REGION SHEARON HARRIS FIGURE NUCLEAR POWER PLANT TEMPERATURE GRADIEiVT IN GASEOUS 8< L(QUID Carolina BOUNDARY LAYERS DURING HEAT SINK Power 5 Lignum Coinpanv SUR FACF COND F iVSATION 6.2A-1 FINAL SAFETY ANALYSIS REPORT n

Pa e 19 of

SUPER-HEAT STEAN

~ AN IMPORTANT PHENOMENA THAT IS NOT CONSIDERED IN CURRENT INDUSTRY CODES IS RE-EVAPORATION OF CONDENSATEs NHEN THE CONDENSATE FILM RE-EVAPORATESN IT WILL ABSORB ENERGY NEARBY AND WILL ALSO EVAPORATE INTO THE SATURATION STATE RATHER THAN SUPER-HEATED STATE~ THEREFORE> THE ACTUAL STEAM TEMPERATURE IN THE VAPOR REGION WILL BE MUCH LESS THAN THE VALUES CALCULATED WITHOUT CONSIDERING RE-EVAPORATIONs THE RE-EVAPORATION PROCESS IS CONTINUOUS AND COMPLICATEDs AND IT NEEDS TO BE .CONSIDERED FOR A MORE REALISTIC EVALUATIONs

~ FOR THE SAKE OF LEARNING THE IMPORTANCE OF THE RE-EVAPORATIONs A VERY SIMPLE CALCULATION CAN BE MADE WITH THE DATA CALCULATED BY CONTEHPT-LT26:

FOR COMPARTMENT VOLUME: VC

= 106,161 FT AT TRANSIENT TIME OF 120 SEC ~

STEAM PRESSURE = 14.7 PSIA STEAM TEMPERATURE = 428'F STEAM HASS (HS) = 2959 LBM CONDENSATE HASS (HC) = 4852 iBM IF IT IS ASSUMED THAT A 10K OF THE CONDENSATE HAS BEEN RE-EVAPORATED INTO THE VAPOR REGION'HEN HS WILL BECOME 3444 LBM WHICH WILL REDUCE THE SPECIFIC VOLUME OF STEAM TO 30.82 FT /LBM WHICH IS APPROXIMATELY CORRESPONDING TO A TEMPERATURE OF 306 F.

(1730DCM/ccc )

Page 20 of 21

1 SUPER-HEATED STEAN ADDITIONALLY'EHAVE PERFORMED SOME PRELIMINARY CONSERVATIVE HEAT BALANCES TO DETERMINE THE OPERATIONAL NEEDS TO SAFEL'Y MAINTAIN THE PLANT ASSUMING EQUIPMENT IS RENDERED INOPERABLE DUE TO SUPER-HEAT.

THE RESULTS SHOW:

1) FOR A LARGE BREAK DOWN STREAM OF THE NSIV, THE NSIV CLOSURE TERMINATES THE BLOWDOWN AND SUPER-HEAT IS NEVER SEENe

2) FOR A LARGE BREAK UP STREAM OF THE NSIV, THE NSIV CLOSE PRIOR TO SUPER-HEAT ~ AUXILIARY FEEDWATER IS

,AUTOMATICALLY ISOLATED TO THE EFFECTED LOOP AND THE STEAM GENERATOR BLOWS DOWN VERY RAPIDLYs DUE TO THE SPEED OF THIS TRANSIENT THE COMPONENT WOULD NOT BE EFFECTED (THERMAL LAG) ~

3) FOR MEDIUM TO SMALL BREAKS THE CALCULATION DEMONSTRATED

= MORE COOLING IS AVAILABLE THEN REQUIRED TO ENSURE THE STEAM GENERATORS DO NOT BOIL DRY EVEN IF THE NSIV S DO NOT WORKS THEREFORE~ THE PLANT CAN BE MAINTAINED IN A SAFE CONDITION FOR AN EXTENDED PERIODe (1730DCM/ccc )

t Page 21 of 21

ENCLOSURE 2

>/i~lVS A<<erJa c L(wl; S Mo,rovl Hmxv IA UH it SQ>er4yi:.c,uw>ihrdi ~

3 K Si'nP J i+ Qnl.lGHT

., 2 5 g,,

. H<</iygR/1-$

MP su~ ( g> sr~

g ~ ~i'0 f'c t.

,~.6~

A/iJ <d<

Qanqa~ f 58 Z(M~ ~unsay,, Cp/L. ikey A@i. Zrc.

Qlg Q~rvq QP~( pQ,IILEI /LCD ~iQC (PW~

.A 4 Q~T~c ~ .

QV'.~'.l V P, Mal('~cc~g'Li~

M.C~. C~agIiavgi ..... Eke~~ ~J Ep.

~, S'A 'P g E~sc o 4 sj~ @gp hl. Af+EQ NRc/gsz./ps@

~<~/'Os%/fs p O t.k~ Pga~ . --- .. tc

~~ Coy, wee /~~/go< ~

'E NGLOSURK THE lola-DE'I aF 'THE K.AM TLINHEL hlAS COb1 IBAD TO SK A S VOI UMK, 5

~

dlJHGTIOH MODEL ~

V0LljNlE, HEAT Sl aSS OF JUNCTION DE5 l ex ATlOH 3I4 I C CONCRETE= S83C f]~ Do 2. I 404 f't ~

S i~ cool~<

po585 cOHCP.KTK =4@84 f'4" 2To5 780 f'4 ~

5 Egl.= 5'40@80 ~

I I 2 00 l HOT COHS DER.KD 3To + 390 I 2,960 WTo g 4oo I. OE,+30 INFORMATION F ROM KBASCQ CAI, ~ AP $ 2.-0l>

VOI VO.L VOL

+

VOL VOL

2. 2 VOL S VOL 5 OUTS) DE OLITBIDE VOL VOL I I