ML19345D438

Proposed Research on Methods of Analysis for Core Meltdown Accidents. Prepared for TVA

ML19345D438
Person / Time
Site:	Sequoyah
Issue date:	06/19/1980
From:	Battelle Memorial Institute, COLUMBUS LABORATORIES
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ML19345D436	List: ML19345D435 ML19345D437 ML19345D438 ML19345D439 ML19345D440 ML19345D441 ML19345D442
References
587-K-2803, NUDOCS 8012150110
Download: ML19345D438 (60)

Text

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i APPENDIX A-4 i'

' CCNS RUENCE ANALYSIS - TECHNICAL DETAILS o

PROPOSED RESEARCH .

! (Proposal / Agreement No. 587-K-2803) i on i

l METHODS OF ANALYSIS FOR CORE MELT 00WN ACCIDENTS r_

to j.;

-p l-Tennessee Valley Authority .,

1 June.19, 1980 s

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EATTELLE

' Columbus Laboratories o 505 King Avenue Columbus, Ohio 43201 F

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, METHODS OF ANALYSIS FOR CORE MELTDOWN ACCIDENTS g to Tenness'ee Valley Authority k June 19, 1980 f BATTELLE Columbus Laboratories

. Introduction In response to the May 15, 1980, letter from Mr. G. F. Dilworth of TVA to Mr. P. Cybulskis of Battelle's Columbus Laboratories, Battelle

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proposes a program to train TVA staff in the use of computer codes for '

r the analysis of core mel~tdown accidents. The specific codes which would be used in the program are the MARCH, CORRAL, ALDOS, SUEDOSA, DACRIN, PABLM, PEDIC, and INPREP codes. The MARCH code describes the thermal d

and hydraulic behavior of a core meltdown accident; CORRAL predicts the transport and deposition of radioactivity within the containment and the

! release of radioactivity to the environment; the other codes are used to calculate the dispersion of radioactivity'in the environmert and the dose N man. The MARCH code has been developed at ECL subsequent to

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the Reactor Safety Study and has been used in on-goicg programs for the NRC. CORRAL was originally written at Battelle's Pacific Nr.rthwest Laboratories for use in the Reactor Safety Study. The currer.t version, CORRAL 2, was developed at BCL. The dispersion and dose codes were writ-ten at Battelle's Pacific Northwest Laboratories.

In the proposed program, Battelle would:

(1) c repare input and perform a sample problem with the codes for the Browns Ferry reactor,  !*

(2) Conduct a workshop to describe how the codes operate, and l

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- 2 (3) Undertake technical assistance to make the codes operational on TVA equipment.

- Ba*.telle-Columbus would be supported in his effort by means of a sub-

+ contract with Battelle's Pacific Northwest Laboratories in the area of

-- environmental dispersion and dose estimation.

Some potential problems and limito ions in the proposed effort should be' identified.

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(1) Because of the differences between CDC and Amdahl ccmputers, it may not be possioie to implement scme

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features of the programs easily on TVA equipment. In

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particular, problems are anticipated in implementing restart and plotting capabilities. Some allowance has been

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made in costing the effort i'n attempts to permit these routines to be made operational. However, until Battelle staff meet with individuals from TVA's computer center, the associated difficulties will not be known. Neither capability is es-

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sential for operation of the codes. .

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(2) The codes used for the analysis of core meltdown accidents have not undergone extensive testing and veri-fication. No guarantee is made of the correctness or ac-curacy of the models. The codes have been used for a variety of plant designs and accident sequences including analyses for BWR pressure suppression containments. Since there are a wide range of potential accident sequences of interest, however, it is possible that a particular sequence cannot be run without modifying the codes.

(3) The planned sample calculation is being performed to demonstrate how the code can be run for potential accident sequences in a TVA plant. The analyses are not intended

< for use in the support of plant licensing. Because of prior commitments to the Nuclear Regulatory Comr ission,

- Battelle would not be able to represent TVA in licensing l

hearings involving the use of these codes.s GATTELLC -COLUMOUS I  :

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a 3 (4) The analyses performed in the MARCH code treat the containment buildirig as a serie,s of interconnected volumes.

Within each volume, conditions are homogeneous and there is j a single atmosphere temperature. Thermal gradients within 4

structures in each volume are analyzed. In order to provide i

! greater stability to the analysis of the containment transient, I

intercompartmental pressure drops are not calculated.

(5) The generation and transport of cctbustible gases within the contaimnent are calculated in the MARCH code.

Within each control volume, all components are homogeneously mixed. Options are available to trigger combustion upon exceeding combustible limits, or at designated times.

Additional models could be added easily to the MARCH

code.

(6) Radiological decay is considered during all phases of the dispersion* modeling _except during transit from thg_ release point to the exposure locations.

(7) The calculated population doses are expectation values based on site-specific data; a probability distribution for consequences is not generated.

(8) The output produced is in terms of population doses

! to organs. From these results latent health effects can '

l be estimated.

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o Scoce of Work Task I. Inout Precaration and Performance of Samole Problem A sample calculation will be performed for the Browns Ferry Nuclear Plant for an accident sequence to be specified by TVA. The M'RCH and CORRAL analyses will first be ;erfccmed on the Battelle-

, Columbus ccmp.ter and later on TVA equipment following installation of the codes. The dispersion and dose calculations will be performed on TVA equipment. it is assumed that TVA will provice the plant design data required for operation of the codes. For the sample problem, the computer codes are run in the follow-ing sequence: .

(1) A MARCH calculation is performed to describe the accident progression and the thermal-hydraulic ,

conditions during the meltdown accident.

(2) MARCH output is run through an input preparation code KCRALIN.

(3) A CORRAL calculation is made to predict the trans-

, port and deposition of the radioactivity within the contaimnent and the release to the environment.

(4) A series of atmospheric dispersion and dose calcul-ations are performed.

The results of the sample problem will be documented and provided to TVA in report form.

Task II. Installation on TVA Eouipment Battelle staff will discuss machine differences and capabilities by telephone with the Computer Users Assistance group in Chattanooga. Modi-I l fications will be made to the MARCH and CORRAL codes on the Battelia COC eATTELLE .CQLUMBUS f

I f 5 equipment as anticipated in attempts to achieve compatibility with the Amdahl computers.

It is expected that one week will be required for a staff member from BCL to assist in making the MARCH and CORRAL codes -

operational.

The dispersion and dose codes will be estabilished on the TVA equipment over an estimated time period of two weeks.

Task III. Trainina of TVA

Staff i

Prior to the Workshop, effort will be required at the Battelle Laboratories in the preparation of instructional material. An outline for the Workshop is provided in Appendix B. The planned duration of the training course is four days. Three Battelle staff will act as instruc-tors: P. Cybulskis, R. 0. Wooton, and B. A. Nacier.

Biograohical data are provided under Personnel.

Included in the course will be:

(1) Description of the basic models and assump-tions of each code, - - - -

(2) Instruction in the preparation of code input, (3) Description of code output and a discussion of the interpretation of results, (4) Demonstration of the application of the pro-grams for a sample problem.

A tentative agenda for the course is provided in Table 1.

Schedule The anticipated start date for the program is September 15, 1980.

A schedule is shown in Figure 1. All work is planned to be completed within

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three months. A four month project duration is prcposed to provide contin-gency for problems encountered in making the cedes operational at TVA.

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6 TABLE 1.

TENTATIVE COURSE AGENDA

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CORRn- .ispersion/ l B ro..:r.s F s e !

Code Code Dose Codes Sample Proble: '

SESSION l i

Course Overview Description Overview of MAP.CH 1 Description of Models Models and Setup and of Models ,

Code Usage Results Description KORALIN; Input and Output coggAt 2 of Models Input Description; Setup and (Continued) Instructions Sample problems Results Input and Output =

3 Input I-nterpretation Description; Dispersion /Cose Instructions of Output Sample Problems Setup end Pesults Interpretation Discussion of Input and Output General 4 of Sampid Problems

Description:

Discussion Output for MARCH Sample Problems and CORRAL I

or APPENDIX A. DESCRI-110:; 0F CO::r; il C L;S 1 A.1 The MARCH Code R

The MARCH (Mel:devn _A.cciden: -.es@csse _ Characteristics) code analyzes the ther=al-hydraulic response of the reac:o: cere, the pri=ary coolan: s/ s:e=, and the conta1==ent s:ste= in ligh: vate: reactors to

, reactor accidents which can lead := core =el:dcrn. Cepending on the acci-den secuence, the code can carry cut the calcula:icns thrcugh the stages of:

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,, 1) Ini.aal blevdern cf the prinary sys:e- cc:lant in:e the contain=ent,

2) Generation and :ransport of heat energy in the reacte c::e, the pressure and :e:perature res;cnse of the pri=ary sys:e=,

boiloff of water fre: '.7e react:: vessel, =el:ing and slu= ping of :he core :o the pressure vessel be:to= head, and =e:al-va:e: reae:1ons in the vessel, -

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3) In:eraction of the core debris vi:h the pressure vessel botto= head and the =elt-threugh cf the vessel,

4) Interac:1cn o_f the core debris vi:h va:e: in the feac:er cavity follevbt , =41:-:hrough of the vessel, and

5) The interaction of the core debris vi:5 the concrete cen:ain-

=ent floor underneath the pressure vessel.

The = ass and energy additions into the centai==en building during l' Stages 1 th:cugh 5 are centinuously evaluated and the pressureate=pera:ure l

response of the contain=ent with or without engineered safety features is calculated. Models are developed that aise calculate the release of :he volatile fissica products f c= :he =elted fuel and follev the heat _sgar.cs associa:ed with a nu=ber of g: cups of fissien p:cducts in:o the centain=en:

or to the eu: side at=csphere if leakage to the ou: side occurs.

1 i Figure A.1 shows schenatically how the MAFCH cede trea:s :he five l ..

s: ages of a nel:down acciden: secuenec. In Figure A.1, INITIAL, 30:'_, EEA!.

h0 TORO?, and IN!ER are the na es of the subrou:ines :ha: perfer: the analysis of S: ages 1 :hrough 5, respec:ively. If the ac:iden is not a large pipe l

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j. break accident, the subroutine INITIAL is bypassed and the BOIL cal-3 culations start i=nediat ely. As also shown in Figure A.1, all fite subroutines are continuously and independently coupled to the con-l I tainment analysis code MACE.

Table A.1 lists in alphabetical order the names of the I subroutines in the MARCH code and gives a brief descriptien of what j u each .eubroutine does.

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stCwo wN l INITI L _ __ _ , A L

,! T PRIMARY SYSTEg agsponse -1 SCILOFF, CORE MELT 001L r

VESSEL HEAO MELT THRCUGH HEAD .

MEE P

DESRis WATE R INTER ACTION IN CAVITY HOTDROP P

DEERIS CONCRETE INTERACTION IN e R v

STOP MARCH CODE TREATMENT OF A POSTULATED REACTOR ACCIDENT l i I

FIGURE A-1.

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i IABLE A-1. SU3 ROUTINES IN THE MARCH CODE Subroutine Descrietien ANSQ Calculates the American Nuclear Society standard decav heat fraction as a functicn of ti=e after shu:dern a d ti=e at power.

ECli Oces the felleving: heat genera:1c: and ::ar.sfer i: :he core, thereal-hydaulics of the pri=ary syste=, beiloff of water f:c: the reae:c: vessel, rel:ing and slue-ing of the core sa:erial to the vessel bo::e head, and 2:-

32 0 reactions in the core and in the bo::c: head.

3UEN Burns hydrogen in ces:ainment vele=es if its cc: centra-

1en exceeds fla== ability li:1:s.

CHNG Reduces the =cl:en debris to single exidic layer when all the =e:al has bee: used up by che:ical reactions.

CONTAIL Calculates :he cass and energy *eakage to out, side a::es-phere through the break area when the contain=en: fails.

CCNVER Converts input units f:c: SI to I:itish.

COOL Calculates the rate a: which :he energy is entracted frem the een:ai:=en: a:=esphere by the coolers.

l CSHI Medels the centain=en recircula:1cn spray water heat exchanger.

D3?ROPS Calcula:es.the effective properties such as density,

, specific heat, ther=al conductiviyt, and rel:i=g or free:ing point in bo:h the cxidic and etallic layers of the debris.

DICOM? Calculates the te:peratures and energies associated vi:h the decompositien of the cens-1:ue::s of concre:e.

DEFINI Lists definitions of variables printed in the output.

. ECC Regulates I ergency Cere Cocling sys:e= vater flow.

ECCHX Medels the Ire:gency cere Ceoling recirculatien flew hea:

exchanger.

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[ n'I TASLE A.1 (Continued)

INTE Cc=putes en:halpies of preducts passing into or out of i

celted debrisfloor.

contain=ent which is in centact with the concrete IQUIL Finds the ecuilibriu= :e:perature of a contain=en:

volu=e af:er-:he effect of the nev = ass and energy l input / output :o/fre= the sa:e vole =e has bee: unifer=ly distribu:ed over the vele=e.

' C EVINTS Initiates and con:rols :he " events" used in :he in;u:

=cthe in :heinput cen:ain.en:

section).cede (ree :ne na=elis: N:ACI in;ut EX1TQ Calculates the gas enthal;ies and the hea:

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ansfe::ed I to s: ue:ures sys:e=. in the tas flov :ath exitinz the tri=arv FICE '

Used to obtain the ou:put fre: :he code on =derofiche.

??LCSS

, Modelsfuel.

=elted the loss of vola:ile fission products f:c= the EEAD Perfor=s the heat transfer aaalysis between the =el:ed core debris and the pressure vessel botto= head, and -

calculates :he botto= head failure.

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• HOTDROP Analyzes the interaction of the core debris with water

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in :ne reactor etvity folleving :he vessel botto= head

!, J =elt-through including such effects as debris frag =en-I tation, hea: transfer, and che=ical reactions.

HRSTy.

Calculates the coefficients rod-to-stea=

in the core. radiation heat transfer

] INITIAL J Inputs initial blevdown coolant into contain=ent for 1arge pipe b:eak loss of coelanc accidents.

INygT Reads the card inpu: da:a in:o the code, edits, and echo-prints the sa=e data in tabular for=.

IN1EA 1 Analy:es the interaction between the molten core debris and the concrete contain=ent l

of the molten debris into concrete. floor, and the penetra:i:-

KOOLIA Does the spray water droplet centain=ent heat ::ansfe analysis if the initial sprayat=osphere l vate 4 --

te=perature is greater :han :he con:ain=ent te=pera:::e.

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MCE 1 Cc=putes inputs frc:

the ces:ain=ent respense :o sass and emergy and INTER.

subroutines 151:lAL, 10:L, HIAD, HOTDRop,

}'.AR C3 The =ain progra:.

1 It calls various subecutines fer perfo::.ing appr:pria:e tasks during an ac:ide:: sequence and regula:es prrgra= flev.

.MIXCTF1 MIXCI?1 with its associa:ed subreu:ines is used to uni-for:ly =ix any = ass / energy addi:' ens to cc :ai =en:

velu es and obtain a new c:1for: :e:perature and pressure

. . for each volu=e.

- E RP Analy:es ths: =e:al-vater reat:1 cts taking place in the pressure vessel bctto: head af:er the core slu=;s.

. PRIY.?

Evalua:es the res;cnse of the primary cr.,olant sys:e= te

' s:all pipe break and transien accidents. It also calcula:es the a: cunt of water /staa: leakage into cc tain-ment through a s all pipe break and/er s&fety/ relief

. valve. .

. PRO?S Contains a table of sa:urated va:er/stea= the odyna=ic properties between :he pressures of 0.09 and 3200 psia.

, Tro: a given value of pressure, te:perature, or specific volu=e, it calculates the other proper:1es by interpola-ting between the values in :he :able. The properties in-cluded in the table are pressure :e:perature, specific volu=es, specific enthalpies, and specific hea: of va:er.

Ql5TER Does hea: transfer analysis a: the =olten debris-concrete

( interface, and calcula:es the ra:e of recession of the

' concrete surface (rate of pene:ra: ion of the =elt into concrete).

QPA3 Calcula:es the hea: radiated frc: he top surface of the t

sol:en debris to the valls of :he cavity.

RD.CT Perfor:s = ass and energy balances in che:1 cal reactions Te + Hy 0, Te + CO 2 ' Z# ' E2 0, Zr - Teo, Cr + H 0, and 2

Ni

• H2O durfcc cne ti:e when :he debris is celting the concrete place in the flocr=e:all.;

of :he cen:ain=en:.

layer cf the debris.The reacticas take P

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bo i 5 .:s A-7 TA3LE A.1 (Continued)

?.EYN _

Calcula:es :he Reynold's nu:ber a=d the fall veloci:7 associated a:=osphere. with the spray water d:cplets in centain:en:

RSTART Catalogs proble=. the files created by :he code and steps the It can be used :c res:ar: the sa:e ;;oble:

f:c:

probla: the beginning er f::: whe:e 1: lef: eft, * , . .. :3.

is res:ar:ed, se:e cf :he input su=bers can ha chanSed if desirsd.

fres :he =ain ; ogra: PJ.RCH.RST;.T.! is the last subrou:ine called SATEST De:e at esphere :inesiswhether or not the s:ea in the centaineen:

sup,e: heated.

SINK Subroutines SINK and SLG de hea: ::ansfer a: alysis between the cen:ain=ent a::es the s::uctures in the con:a'-;.ere andhey -- thecalculate valls andthe a:ount cf hea: lost to the va'is and the structures and an average vall surface te:pe:a:::e in each centai=:ent volume.

• SLA3

See SINK above.

SOLIl'IQ

/.djusts the mass transfers betvee the contain=ent volutes so that the pressure in all volu es a:

i is the same. the end of a :izes:ep SOLLIQ Calculates the effective =el:ing peint of the oxide layer of the debris which is pene::a:ing into the con-crete floor of the contai=ent building. It also ca'.culates the change in the effective specific hea: of the oxide layer due to mel:ing or freezing of 1:s constituents.

SOURCE A::anges the contai=ent velu=es in the order of decreas-ing pressure before inter-c :part:en:al transfers :ake place.

i S? RAY Perfor:s :rass and heat transfer calculations, be:veen the spray water d:cplets and :he centain=ent a e: sphere.

It also calcula:es hev much va:e and energy is added l

to the contain=ent surp as a resul: of spray a:: ion.

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A-S T A31.E A .1 (Centinued) 3 TIX?

Calculates the equilibriu: :her: dy:a:1: properties such j as partial pressure of s:et=, air, and 1:s constitue.. 5, specific enr'. .;y, specific vole =e, and mass of s:ca: and i

vater d:cplets in con:ain=ent a::: sphere af:e: unifer:ly distribu:ing the ne: effe : of any = ass / energy addi:1cns c: deletiens in een:ain en: vole:es.

TOIOM Calculates :he :hereal b:undary layer :hicknesses in :he debris and :he cencra:e.

E TS 1.ists units used in :he cu:put f::= :he cede.

i k'Si!M Li=i:s the stea: cass in the centai::en: a:=osphere te

ha: =inimu: value yhich veuld ':a presen: if the cc :ain-ent tolu =e vere filled vi:n 40*? sa:urtted ste;:.

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}9 A.2 The CCP3AL Code The analytical model for the connAL Il ec=p.::er program is a WR or WR reactor containmen: system cchposed of up :o fifteen (15) individual ecmpartmen:s. Any compartment can be assigned to represen:

any of the rooms, cavities, well.s, filter chambers , e:c. , cf a cc=ple:e reactor con:ain=ent sys tem. The cc par:aints can be connec:ed to each other in any combination of mul:iple seriet/ parallel arrangements.

Radionuclide release by any of fcur release nechsnises can be specified in any of the cc g :se .:s. ::creany re' ea,es cccur in:e :he 4

d:ywell of a n7. reac:or and into one of the subecepar:; en:s of a 7;p.

reactor.

The fcur release =echanisms include gap (cladding rupture),

fuel mal: int, vapori:stion, and steam e:.:plosion. Since cladding failure

] cus: chrenelogically occur before :he' release by ary ether =ech nism the progra= assu=es gap release has occured a: :he ini:ial proble: ice.

The releases by the other three =ec.taniscs cay occer at any other. :ime and in any sequence follouing the gap release.

The gap and explosica releases are burs: :ype relea~ies, i.e.,

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" the full quanti:y of radionuclides specified as being released by these cachanisms is released at one time. Radionuclide release by the cel:

} and vaporization cechanisms, herever, occurs ever a period of :ime which is specified by the program user. To pro;erly age the continuous

} celt and vaporization releases they are divided in:o discrete step i

i releases. The cel: release is divided in:o ten equally si:ed releases occurring over 20 time steps (i.e., one release every c:her ti=e step).

j Each release is independent age-wise from the other nine. The vaporiza-tica release (occurring at an exponential rate) is dividad into 20 s:ep releases vi:5 each successive release a: an exponentially lower

! f value than :he first. The sum of :he firs: :en releases (occurring over 20 equally spaced time steps) equ:ls 1/2 of :he total release, and the retaining :en (occurring over :en equally spaced :ime steps) equal the other 1/2. The durt,' ion of the period cf :hc first ten releases is one half-life. The duration of the secend :en relcases should bc three

! half-lives for a rc:conable appro:.:in.:: ion of ar. cxpener.:ial decay.

The accuracy of :ac ou:put depende up.an the ra:e of ch:nge of :he rate cocfficiente.

.i Therefore, short time c: cps ..rc desirable ire.edictoly O -

- -- - . = . . __ - _ _ - - ~ .-

1 o**B Ul 1. .%@

.s-10

_oon af:cr each discrete release (aging is rapid a: firs:, espccially if sprays are engaged) .

Long time steps are sufficien: fer cid releases.

Tission product removal ra:es an,d :hermodynamic da:a for condi-tiens wi:hin each compartment as well as intercompartmental flow and fission product rencval can be specified at up to twen:y (20) sequen:ial

' event times including the initial and final times of :he problem. The data can be in:e:pola:ed between the sequential event ti=es using quadra tic in:e:polation. If specified, calcula:icas are performed at in:c:vals be::<een :he seque..:ial even: :iras as de:e::t,e by ca;ee,3:te -

3, time step incremen:s.

During the periods of the cel: and vapor releases the :i=e step incre=en:s are determined by the p cgrca as noted abeve.

,. Dr all c:her :imes during :he p chle=, :he :ite s:ep incremen:s are

} conta11ed by the user. + '

Radienuclidas are recoved f:c= the gas and va:er sapor strea= as it flows :hrough the various ccepar::ents by particle se:: ling, dep:sitien, spray rencval, and/or by fil:ers. In scre cases, re=cral ra:es rates are calculated within the program based en in;c: da:a. An er:a=ple is the se:: ling ra:e cf par:1cula:e :::erial which is 1:self a function of the particle size range which is a da:a inpu:. In c:her cases, removal rates are input directly. An exseple is the filter receval rates for partice-la:es or iodine. Leakage rates of the radionuclides f:c= any compartment t

to cutside of :he containment sys:e= can also be input.

In addition :o loss of radionuclides from the contain=ent i

to :he environ =ent by leakage the program aise permi:s a one-time loss to the environment through a rapid release of fission products due to a con:ain=en: failure which is not associa:ed with a steam e>:plosion.

I Such an occurrence is referred to as a puff'" release" al: hough it represents a release of fission products from the con:aineant system and

{ not from the core. The user can designate up to five ccepartments which are no: affec:ed by a puff release.

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The program considers eigh: groups of radienuclices released frc the fuel: noble gases, element:1 iodine, erganic iodine, cesie=-

rubidium, telluriu=, barium-strontium, re:Senien and lan:hanc=. The 1

noble gases, elemental iodine, and organic iodine each have unique rezcva* .

properties from the steam-air =ixture as it fleus through the cen:ain=en:

sys:em.

The remaining five radionuclide groups have si.=ilar removal properties (characteris:ic cf par:iculate ma:erials) whi:t are differen:

frc

} the neble gases and iodina gre;c;s. Censceuan:1::, during :he calcula icns involving frac:icnal re=cval and leakage frc: :he cen:ai. e.:

system they are censidered as a sin;1e "radiencelida" greep referred to as parti:ulates.

n Thes the pregram felicus only four types ef release o raterials thrcush the contain en:

sys:en: noble gases, elemental icdi'..e, organic icdine, dnd par:iculates.

The pregram perferns all calcula:icns l on a relative basis , i.e. , fracticns of ecch of :he fcur release ra:eria".s f1 cuing thrcugh each cc= par: ent, being recoved, e:c.

Output accen: data fer each of the fcur release ::erials inc1 de the cf =sterial which is {rborne in es:h c::partmen: and the ancun:

escaped to the envirennent.

These da:a are presented as a fractics cf on'.-,

that a=cun: released from the core by each cechanis=.

Dese reduction fac:crs are also presented for each of :he' four greups for each release =echanist.

l i

In addition, the cu:put data include the fracticn of the total core inven: cry .

of each of the eight radionuclide groups which has leaked :o the envirc e .:.

The results of the re= oval and leakage calcula: ions fer the particulates are combined with the core inventory release data for each of the five

" particulate" radionuclide groups to deter =ine :he frac:icn of the core in-ventory of each specific group which has leaked :o the environment. The fractional leakage of the core inventory of the noble gases and iodina grcups are calculated independently.

oo g

.j O D[3'l oj [2 - :2

t A-12 A.3 Descriptien of Dispersion / Dose Models The codes that would be provided by the Pacific Northwest Laboratories for analysis of atmospheric dispersion and dese to the population are:

ALLDOS e population dose summation and report preparation l SUBDOSA e dose factor generator for external dese from air submersion DACRIN e dose factor generster for inhalatien uptake PABLM e terrestrial pathway dose factor generator PEDIC e atmospheric dispersion and population evacu-ation calculation INFREP e input preparation aid for ALLDOS The code ALLDOS uses factors generated by the other codes to calculate total

?

population dose for each of several selected organs of reference from all significant environmental pathways. The computer code DACRIN implements the ICRP Task Group on Lung Dynamics lung model to describe deposition and transport through the respiratory system. The co=puter code PABLM odels terrestrial pathways that result in consumption of containminated foods plus exposure to contaminated ground. The effects of atmospheric dispersion and population evacuation' are estimated by the ecmputer code PEDIC. This code e= ploys an evacuation mode 1' developed by Nuclear Regula-tory Commission staff. The convenience cede INFREP will be provided if TVA facilities include ccmpatible interactive operation and if time permits.

l 930 PD'G~l 6 D"dh\

3 b l L JN

. a l

.- . _ -~ _,

APPENDIX u 5 SINGLETON TESTING - TECHNICAL DETAILS Results of various glow plug perfor=ance, reliability, and endurance tests are presented.

A. Voltage Vs. Temperature Test Six General Motors 7G glow plugs were energized with voltages ranging from 11.0-V ac to 14.0-V ac and the temperature was recorded r,ft3r periods of eno minute and three minutes. The resultr, of these tests are shown in table A-5.1 Temperature measurements were made with a Mikron Infrared Thermemeter, Model Number 57.

l As can be seen frem the table, after three minutes at 12-V ac, the temperature is censistently at,cVe 1600 F, and at 14-V ac, the temperature is con:13tentiv above 1c00 F after one minute.

B. Preconditioning Test Three-hundred and two GM-7G glow plugs have been' subjected to a preconditionin5 test which was designed to eliminate plugs with manufacturing defects. The test consisted of three steps:

1. Each plug was energized with 6-V ac 1 0.5 volts. After five 1

l

Oinutes, a continuity eneck was made by confirming current flew to the plug. .

2. Each plug was energized with 12-V ac

• 0.5 volts. After five minutes, a continuity check was made by confir=ing current flow to the plug.

i 3 Each plug was energized for one hour with 13.9-V ac ^- 0.1 volts. The surface was confir=ed to be 1540 F or greater i

af ter being energized for three =inutes. Alter cne hour, the plug was deenergized and allowed to cool to a=bient, energized again, and the 1540 F =ini=u temperature j confirmed.

i During testing cf the first 16 plugs, six failures occurred.

These failures were attributed to volatizable material, possibly water, inside the sheath. The volatized material was unable to i

escape rapidly enough to prevent rupture of the sheath. At this point, the test procedure was modified to include a 5-minute

interval at 8 and 10 veits. Only eight of the remaining 286 ,

plugs failed, after the test precedure was modified, for a failure rate Of 2.8 percent. The overall failure rate was 4.6 sa percent. Any and all additional igniters installed will be selected frem the group of plugs which have successfully passed the preconditioning test. The 32 igniters presently installed at l Sequoyah unit 1 were subjected to the preconditioning test before installation.

i I

0. Cycling Lnd Endurance Test '

Frc= the lot of 288 plugs which successfully passed the crecondittening test, 50 plugs were selected at rando: for additional testing. The test cen:isted cf two ; arts.

1 l

1 Each plug would be energized until the surface tencerature had stabilized, deenergi:ed and allowed to ecol to 1 tient, then the cycle repeated for 10 cycles.

2. Eacn plug would re=ain energizec centinucusly fer a period of 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />.

These tests are presently being conducted; the results will be available at a later date.

l

[

l i

_ n - - - -

L

TABLE A-5.1 VOLTAGE VS TEMPERATURE Voltage ter Temperature Aft Plug No. (Volts AC) Te:peratureA{F)

One Minute ( Three Minutes (grF) 1 11.0 1480 1530 12.0 1610 1610 13.0 1715 1740 14.0 1820 1830 2 11.0 146L 1530 12.0 1650 1675 13 0 1710 1740 14.0 1810 1815 3 11.0 1410 1510 12.0 1570 1615 13.0 1710 1735 14.0 1790 1810 4 11.0 1460 1530 12.0 1580 1640 13.0 1675 1735 14.0 1810 1820 5 11.0 1550 1605 12.0 1630 1750 13.0 '755 1795 14.0 1820 1830 6 11.0 1535 1585 12.0 1660 1695 13 0 1765 1795 14.0 1825 1830 l

I i

l l

l L

APPENDIX B EQUIPMENT SURVIVABILITY I. Introducticn Events involving core ' degradation have the potential for producing environmental conditions that have not been co.isidered in the evaluation of instrumentation and equipment for present i design basis events. Discussions of temperature respense curves to be used fcr evaluating equipment, heat transfer mechanians, and the value of an ice condenser plant cra provided below. A comparison of the temperature curves with data from the Fenwal tescs is included. Considerable efforts are planned to increase the understanding of hydrogen burning and its effects on equipment. These programs are discussed in section II of this j report.

Temperaturt Effects The NRC, i.t quest!cns about the ability of the Sequoyah Nuclear plant to withstant THI-type events, has requested a temperature curve based on transient containment analysis. Figure B.1 is the requested curve, originally submitted in Volume II of the l

I Sequoyah Degraded Core Program Report (September 2, 1980). The figure represents tne results obtained from the CLASIX computer code developed by Offshore Power Systems and provides the hypothetical atmospheric temperature response for the burning of I

hydrogen that results from a small LOCA without emergeacy core i

~

m

) -. .-. ..

O.,

v g

a 5-5 "

l e G .

a:

• l 0 a

i f E-s > E N

fi= L--?- 1 ='#pD

-- & c A 0 , , , ,

1000 2000 3000 4000 TIME (SECc: irs)

A - Calculated Atmospheric Te=perature Without Burn

- LOTIC S2D case

- assu=ed as initial te=nerature for heat sink calcuations (160 F) ~

3 - yeasured Atmospheric Te=perature With Burn '

- T:E - 2 (2to* F)

C - Experimental Heat Sink Te=perature With Burn

- Fenwal Phase 2, Part2, Test 2 (multiple burn)

- =axi=um igniter box internal te=perature (238 F)

D - Calcuated Heat Sink Te=perature With Burn

- T7A analysis mav4m;r heat sirl temperature (275 F)

E - Calculated At=cepheric Te=perature With Burn .

l

- CLASIX S2D case

- no structural heat sinks FIGURE B.1 l

[

. . . . .= ..

cooling. The release of hydrogen is terminated when I

approyimately 75 percent of the zirconium cladding has been oxidized.

l The CLASIX code models the major compartments and flow paths in i

an ice condenser plant. The code also models hydrogen burning, the ice bs4, upper compartment sprays, and air return fans. The steam and hydre jen mass and energy release rates from the reactor coolant syster were obtained from a MARCH computer code run for Sequoyah Nuc3 3r Plant. The CLASIX. code case presented assumes that all the hydrogen in a compartment will burn when the

tydrogen reaches a 10-percent by volume concentratice.

In addition to obtaining ~the atmospheric temperature, it is necessary to evaluate the total energy available to heat up components. Present equipment qualification done by testir.i; is i

based on the atmospheric temperature alone. This simplifies the procedure and provides conservative results since sufficient energy is supplied to maintain the desired atmospheric temperature. To be completely accurate, present equipment qualification for LOCA's and MSLB's should also consider the total energy available. However, for these events, the atmcapheric temperature profiles are not so severe as to preclude qualification on the basis of temperature alone. This is not the case for degraded core events, as the calculated temperatures are too extreme for equipment to survive because there is h insufficient enercy available to support equipment temperatures at atmospheric temperature levels.

_ _ ~

l 4

In the ice condenser containments, as high temperature steam and hydrogen are released from the core and burning occurs, the pressure in the lower compartment starts to rise. Large quantities of the icwer compartment atmosphere are driven into the ice condenser.and, in the process, over 75 percent of the energy released by burning or from the core is removed by the ice. This effect is also seen in conventional LOCA's and MSLB's where ice condensers have lower design conditions than other PWR containment designs.

It must be noted that much higher atmospheric temperatures (2200 F) are calculated in the lower compartment of an ice condenser plant than would be calculated for other containment designs.

T*as is not due to solely massive energy releases, but is more a result of the reduction in lower compartment gas and vapor mass due to flow into the ice condenser. This effect ca0 be readily seen in the equation for the increase in internal energy of a gas:

dQ = m cy dT.

where dQ = the change in internal energy m = the mass of gas cy = the specific hes.t at constant volume, and dT = the temperature enange in the gas i

For a given change in energy, the temperature change is inversely  !

i l

- - . _ _ - , . . - ~ . . . _ . _ ,_ - _ . , -

, . _ _ W

proportional to the change in mass. Reduce the mass by a factor of two, and the temperature increase will double. Even though the temperature of the lower compartment atmosphere may reach 2200 F, there is only a fraction of the amount of energy available to heat up equipment and other heat sinks 7{)

cc:;- as there is in a dry containment.

As a result, the ir. crease in component te=peratures vill be less in an ice condenser than in other PWR contain=ent designs. To quantify the value of the ice condenser, TVA has performed evaluations of the temperature rise of the lower cc=partment heat sinks that result from a degraded core event. Considering only the lower compartment steel heat sinks inside the crane wall (SQN FSAR Section 6.2), a uniform temperature rice of 150 F will remove all of the energy released that is cot bsorbed by the ice condenser. If the steel heat sinks in the dead-ended regions are also included, the heat sink temperature increase required is reduced to 1150F. This means peak heat sink temperatures will be less than 300 F. In actuality, some of the energy credited to the heat sinks will stay in the atmosphere and be removed by the flow into the ice condenser as a result of air return ran operation, and the concrete heat sinks will remove some energy also. The numbers provided represent an upper bound on the temperatures seen in the heat sinks. The CLASIX code, at present, does not model the heat sinks. When this option is added, we do not expect major changes in the peak atmospheric temperature, but we also expect modest temperature increases in the heat sinks which will be less than the 150 F discussed above.

i In addition to the transient analyzed with CLASIX, an evaluation of a continuous burn was made. This analysis indicated the major concern to equipment would be the result of radiation from the flame. The analysis was generalized by computing the heat flux at various distances from a flame. The analysis showed that a 4400 F flame temperature will produce a radiativa heat load of 280 STU/hr-ft2 10 feet from the flame. The heat lead 50 feet from the flame would be 11 BTU /hr-ft . Most critical equipment would not be affected by cent'inuous. burns since/6ihe:nlI/

ww.alJ equipment in a line of sight with the flame assi be affected.

However, areas that have a high potential for continuous burns such as near the pressurizer relief tank would be reviewed to determine that important-components are not in the vicinity.

Fen,'al Tests The tess program at Fenwal was basically set up to confirm the I

ability of the igniters to burn hydrogen under a variety of j conditions. We do not believe the results from Fenwal represent the temperature responses that would be seen at Sequoyah Nuclear Plant. The tests do lend credence to the temperature response that have been discussed earlier and provide experimental i

j evidence that hydrogen burns do not reprsent an unusually severe l

l test for equipment. Particularly, during the second phase of I

testing, four tests were performed with the explicit intent of measuring the temperature rise across equipment similar to the critical components necessary during'and after a hydrogen 1

I l

generating accident. These tests are discussed in v.-aster detail in the following material:

A. Test Results The Phase 1 testing was conducted to prove the igniter's ability to burn hydrogen under various environmental j conditiens. The Phase 2 testing wns cenducted to further

l l test the ability of the igniter as well as to observe the effect of hydrogen aurning cn a representative sample of equipment.

1. Phase 1 Testing Although it was not the purpose of this group of tests

[

to demonstrate equipment survivability, the test results do provide useful data. Primarily, the IDIS igniter box demonstrated that it cou1* survive repeated hydrogen burn tests and still function. Table 1 lists the Phase 1 tests and the four temperatures which were recorded for each of the tests. The test results l

l indicate that the temperature rise across the igniter box (T - T y) for the 12-voluce-percent hydrogen tests 3

averaged 48 F, for the 10-volume-percent tests it averaged 38 F, and for the 8-volume-percent tests it averaged 17 F.

In several of the Phase 1, 12-volume-percent tests, the

TABLE 1 TABULATED RESULTS l

Tv V Baro R/fl T amb Tg T T Tg 2 3 1H, ( F) Ft/Seo) (mmHg) ( F) ( F)

(%) ( F) ( F) ( F) 12 180 0 763.7 53 70 230 395 220 1050 8 180 0 763.7 46 76 310 330 -

710 8 180 0 757 3 73 61 245 140 205 190 12 120 0 763.9 82 55 280 205 178 748 8 138 0 763.9 68 50 129 150 150 222 12 176 0 759.4 95 , 67 270 250 228 1000 8 190 0 761.9 65 72 218 200 195 657 12 145 5 767.2 88 56 255 200 200 1000 12 130 10 767.2 63 75 212 195 175 1000 10 145 10 761.1 85 71 200 247 190 -

10 146 5 761.1 60 83 242 is6 178 800 12 350 10 757.0 85 78 472 403 395 1000 12 350 0 756.4 47 88 450 402 400 495 8 350 0 752.5 76 78 408 360 370 390 1.egend

$11 2 - !!ydrogen Test Concentration (5) l Tv - Vessel Test' Temperature ( F)

V - Air Velocity at Glow Pub (Pt/Sec)

Baro - Barometric Pressure (mmHG)

'R/H - Relative Humidity (%) '

T amb - Ambient Temperature ( F)

T - Glow Plug Box External Wall Maximum Temperature ( F) 3 [

T - Vessel Internal Wall Maximum Temperature ( F) 2 T - G1 w Plu8 Box Internal Maximum Temperature ( F) 3 T

4 - Vessel Air Maximum Temprature ( F)

E50343.02

TABLE 2 PilASE 2, PART 1 Test .

Time No. T T T To T e o$ o$ o$ k P, g p P

$b/in , g"F i

s0 ["

H il O see Mg mmHg malig "

1 136 210 175 -

960 96.16 838.57 134.42 2

38.75 6.85 15.8 36 56 138 141 130 140 2a 165 85.64 843.18 141.65 31 5.4 15.9 76 41 185 143 148 330 - - -

16.0 - - - -

3 140 140 135 145 74.77 846.0 147.39 4 142 ,142 1.5 5.5 15.5 35 55 142 142 142 64.67 856.0 157.17 1 11 17 80 44 5 144 144 144 144 144 53.9 '858.69 165.44 6

.25 3 17 -

51 138 230 183 140 685 86.25 850.16 141.66 142 36.0 4 15 34 49 7 190 152 8 212 335 64.68 856.18 157.17 14.0 9 17 85 45 280 242 240 700 107.02 535.1 428.08 212 30.0 9.6 17 74 62 9 212/225 200/200 212/217 235/245 64.21 577.9 428.0P, ,78/2,66 10 16,5 $5 65 210/210 212/225 2'o/247 227/269 205/208 64.21 577.9 428.08 .20/3.2 1.88/5.88 19.75/25.7 52 50 Bar.

g H, S, V ill 2 b'Nd 9 765.3 761.4 8

7 761.4 6 767,7 5 767.7 5 8 767.7 5 6 768.0 10 767.4 0/5 6 7f.7. 4 0/5 6 702 3 Note: 1) For Test 10, T is the maximum vessel air temperausee and gT is the maximum vessel2 wall temperature.

E50288.05

l 1

I LEGEND for TABLE 2 Tg = initial test temperature Tg = igniter box exterior temperature T2 = vessel wall temperature -

T3 = igniter . box internal temperature ,

Tg = vessel air temperature P,P H 0 = partial pressure in mm of.Hg air' H : 5 hydrogen (preburn) chromatagraphic analysis HP = 5 hydrogen (post-burn) via chromatagraphic analysis 0" buri velocity 5"lip is j hydrogen given in test conditio1 V s air vel) city across glow plugs R/H = relative humidity i Amb. Temp - ambient air tes,perature prior to test Bar. Press - barometric pressure in mm of Hg E50288.05 e

l

,. - . . . _ - . - . - - . . . -= _ .. - .

k i

TABLE 3 Phase 2, Part. 2 Time Time to to Amb Test T2 T Tq P P P P Ign H/H Temp No. T1 Tj H air il O P max 3 _

go 2g6 4 759 1 -

7.8 2 11 sec. 1.5 min. 95% 38:

1 330 138 183 scrm aus Hg, Ib/in F F F F F F 4 759.1 6.09 2 12 sec. 1 min. 95%

Extrasen g4 338 133 Igo 34 238 F F scfm mm lig lb/in F F F F o

' 4.5 sec. 1.4 min.

2 Ig5 4 **768.5 -

10.15 2 57%

37 Igo 2g5 3g7 238 F F F F F F scfm mm lig Ib/in Ba'r.

H 11 .Su V $H 2 Press y a 759.1 mm Ilg 759.1 min lig 768.5 aus Hg "From H input initiation 2 '

seInitial conditions - 1 atmos., T=160 F seeTest considered extra due to uncertainty in 112 input E50323 09

LEGEND FOR TABLE 3 T initial test temperature Tg g= = igniter box exterior temperature T2 = vessel air temperature T igniter box internal temperature T 3 = vessel wall temperature Pg =P Hj air' H O2= Partial pressure in am of lig H = % hydrogen (pecburn) chromatagraphic analysis 11 = 5 hydrogen (post-burn) via chromatagraphic analysis S = burn velocity 5"H2 is 5 hydrogen given in test ~

condition V = air velocity across glow plugs R/H = relative humidity Amb. Temp - ambient air temperature prior to test Bar. Press - barometric pressure in mm or lig 4

ES0323.08

In Phase 2, part 3 (Table 4), we discovered that the teflon insulation on the thermocouples had melted.

.1.

Therefore, the temperature data for these tests is suspect. Neglecting this, the temperature rise across l the igniter box according to the data collected is

still no larger than the part 2 continuous injection f

testa mentioned above.

i j

In the part 4 tests (Table 5), the thermocouple located inside the igniter box was removed and relocated so that the temperatures measured were the inside and outside of the equipment placed in the vessel for survivability testing. In-those tests, the maximum temperature rise inside a Barton transmitter casing, a solenoid valve, and a limit switch were 14, 99, and 41 F, respectively,,for exposure to a 12-v/o hydrogen burn.

Table 6 is a list of all the equipment exposed to at least 12 v/o hydrogen burns during the part 4 tests.

These components are representative of the critical l ccmpenents needed following a TMI-type accident. The majority of the equipment did not experience any visible signs of degradation. The only exceptions were some paint samples on concrete blocks which showed slight discoloration on the corners and one piece of cable showed two small (1/2 x 2 inch) scorched spots on

'the black plastic coating. Table 7 is a list of

TABLE 4 PHASE 2. FART 3 Test Tg Ty T

. Tice Time Aab 2 7 Tg P P Bar.

3 P P to Psas to dI a R/H Temp '

No. F 'P *F F F H _ Air psid O Press ,

_ sea see

_ 1 F M H 5 V , Q am itz

. 42 -

665 135 85.72 '

771 5 -

56.25 - -

45 na Hg 39 - - - ~ 10 778.5 1 82 650 157 84.47 760.2 -

50.0 .56 11.59 50 47 - - -

an Hg - 10 763.2 2 80 48.27 756.2 -

31.2 1 56 22.0 34 48 - - - - 6 756.2 3 80 502 157 4 acra 755.5 -

3.12 6 89.5 34 48 - - - - -

755.5 1A 73 358 142 85.67 771.0 -

42.2 1.125 15.0 ma Hg 50 40 - - - - to 772.5 Notes:

1.

2. AveragesprayflowratedurfngtestmeasureJtobe19gpa.

Temperature spray appros 50 F rce all tests.

3.

4 Igniter box enterior thermocouple rell off during the course of the experiment.

Legend for this table same as for Table 3.

Caroled data are uncertain due to thermocouple insulation failure.

DE02:FEWAL.2

y ._ . . _ . _ . _ . _ . _ . _ . . _ . _ _ _ ._ __ _ . . _ __ . . _ . . _ . . _ _ . ._. _ __ _ __

TABLE 5

. PHASE 2. PABT 4 Time Time Aab Tszt Tg T*

y T8 T8 T* g 78 T86 P P P P to Paan to Ign R/M Temp

• 2F 3 5 N *. 'F *F *F g F F *F Air HO psid sea see 1 *F ha u V 1 129 255 140 230 150 135 710 124.1 830.3 111.7 60 .64 27.1 55' 40 - - ' - -

14 129 '357 130 143 ' 140 133 735 124.1 830.3 111 7 ,61 .60 27.2 93 26 - - - -

CTemperatures are as designated below:

T a Maxisua test vessel unll temperature '

T ,ge Barton transmitter casing maximum interior air temperature (thermocouple #2) e Barton transmitter casing r simum esterior surface temperature T a Barton transaltter casing maximum interior air temperature (thermocouple #4) .

- T s, Barton transaatter casing maxteue interior air temperature (thermocouple #5)

T s Maxieue test vessel air temperature 1

I Pre- Post-Bar Vac Burn Burn Ign Q Press Pulled Anal Anal Voltage .

12 756.6 12 12 751.6 12

• l

PHASE 2. PART 4 Time Time Aab Tatt Tg T* y T8 2 T* T*

g 7* 7* P

'P P P to Paan 3

• $F 6 to Ign R/ti Temp No. *F *F *F *F *F F H. Air HO psid sao see 1 F a u V 2 129 365 240 228 235 170 760 124.1 830.3 111.7 63 .55 25.8 30 55 - s - -

2A 129 395 250 183 185 138 755 124.1 830.3 111.7 58 .65 26.3 57 27 - - - -

eTraperatures are as dealgnated belou:

T ' " 'I""" E*** *****I "*II ***P*#**"

T,1a Solenoid valve maximum exterior surface temperature T a Solenoid valve maximus interior air tesperature Ta Limit suitch aantaus exterior surface temperature Tg a Limit switch maximus interior air temperature 7' *l""" t**L *****l *l" L**E*#*t"#*

6 Pre- Post-Bar Veo Burn Burn Ign Q Press Pu11ad Anal Anal Voltage 12 755.0 12 12 771.0 12 FEW AL. )

9

PHASE ? .' ART 4 Tsat Time Time Amb Tg T- T T Tg P P Bar 3 2 3 P P to Psau to Ign R/H Temp No. F F F F F At U ,

H psid see

_ sec 1 F 4( V Q Press I

5 146 379 790 203 432 109 841.6 142 49.0 1.7 27.8 60 30 - - - - to 760 2 mm Hg 6 146 ' S-2 760 195 510 109 841.6 145 50.0 1. 's 56- 55 65 - - - - 10 -

Nittas

1. Test conducted wb4 , 41 12 volts. P a 21.1 pala; 6.4 psig.

2. Test conducted 'vith ignitar et 10 volts, P a 21.1 pala; 6.4 psig from test 6 BX e&ble - no vis'ible damage b)het plastic cable - single spots (2) appros 1/2"x2" spaces scorohod I

LEGEND FOR TESTS S AND 6  :

Tg = initial test temperature T

T,3-==vessel igniterair box exterior temperature temperature T' igniter box internal . cmp'-ature

= vessel wall temperatu.'e Tf=P P,- ,gp, PH 0 = partial pressure in mm of Hg H

H 2= 2 H,E = % hydrogen (preburn) chromatagraphic analysis $ hydrogen (post-burn) via chromatagraphic analysis S = burn velocity .

%"H is % hydrogen given in test .

bondition V = air velocity across glow plugs 2

R/H = relative humidity '

Amb. Temp - ambient air temperature prior to test

. Bar. Press - barometric pressure in mm of Hg Elo339 01 -

i +

q e.

TABLE 6 COMPONENTS PLACED IN FEh"4AL VESSEL FOR THE EQUIPMENT SURVIVABILITY TESTS No. of Test Effect Ecuic=ent Exposures of Tests

1. Paint samples (on 1 Very light oxidation film over concrete blocks) paint, deeper discoloration of excess paint on corners of concrete blocks

2. Paint samples (on 1 Very light oxidation film over metal slabs paint 3 BX-type metal conduit 1 No obvious degradation 4 Black plastic coated 1 Two secrch spots (2" by 1/2")

cable

5. Namco limit switch 3 No obvious degradation

6. Asco solenoid valve 3 No obvious degradation

7. Barton transmitter casing 5 No cbvious degradation

8. Miscellaneous wiring 1 No obvious degradation 9 TVA igniter assembly 30 Assembly still functions well.

Transformer coating scorched.

Transformer wires scorched.

'drap on transformer windings scorched.

i

, Glow plug connector scorched.

l Transformer laminations. corroded.

l Cover gasket scorched and hardened.

Assembly exterior lightly corroded.-

l

10. Duke igniter assembly 6 Cover seal burned, but no other obvious degradation

(

[ 11. Fischer Regulator 1 No obvious degradation i

e E10331.01 i

l l

• i i

4

. TABLE 7 MISSCELLANEOUS EOUIP!'ENT IN FE!T4AL VESSEL DURING TESTING No. of Test Effects Equip =ent Exposures of Tests

. '4 cod block (4" x 4" 20 Thin browning over =uch of wood f

5-1/2") surface

2. Thermocouples 14 0 No obvious degradation 3 The mocouple lead 30 Teflon insulation turned off most wires (first set) of wires

4. Thermocouple lead wires 6 No obvious degradatiot

_second

( set)(wrapped in aluminum foil)

5. Spray nozzle 5 No obvious-degradaticn

6. Fan =otor (1st)(1/150 hp 20 Light oxidation over surface; shaded pole motor) soldered connections failed on last test

7. Fan motor (3rd)(1/150 hp 1 Failed after high temperature shaded pole motor) , transient burn test; soldered connections detached E10331.01

(

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1 miscellaneous equipment which was also included in the test vessel during the testing. This list is provided to demonstrate the minor effect of the hydrogen burn environment on even off-the-shelf equipment.

B. Comparison with Sequoyah The test conditiens which were chosen for these tests do not directly model the worst environmental-condtions which might exist inside Sequoyah containment after an accident. The test conditions were . ;ead selected to present significant environmental challenges to the effectiveness of the igniter by which it could be evaluated.

The 8-percent hydrogen concentrations for the Phase 1 static tests were selected to bound the volumetric concentrations where we believed hydrogen burning would begin. The 10a and 12-v/o tests were conducted to determine the effect of environmental conditions on concentrations where we believe complete burning would occur.

Other Environmental Effects In addition to temperature eft'ects, critical components must be evaluated for pressure and local detonation effects. Figure B.2 provides the containment pressure response for the event that was 4

used to calculate the atmospheric temperatures. Once again, there is a pressure pulse associated with each of the burns with

.,. .-.4 ,, _ .

• * "*. . . .. w. . . . . . .

1 D"O D'W i

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6 the highest pea'. reaching 26./ lb/in2absolute. The design 7

pressure for Sequoyah is 26.4 lb/in2absolute; therefore, pressure is not a concern. Detonations have the potential for damaging equipment and, with the exception of valves and piping, TVA has assumed that any equipment will be destroyed if it is in the immediate vicinity of a detonation. Even given this assumption, detonations do not require equipment modifications or special protection features. This conclusion is based on the following:

1.Section IV.C and Appendix H of the Sequoyah Degraded Core Program Report, Volume II, provide discussions of why detonations are unlikely.

2. Even if pockets of hydrogen at high concentrations are postulated, the igniter system will prevent any detonations except very local ones (see Appendix G, Sequoyah Hydrogen Study, Volume II).

3 The effects of a small detonation are so_ localized that only equipment located within a few feet of the detonation will be advertsly affected. Redundant instrumentation and equipment will still be available. Since it is unlikely-that a detonation can occur and, because any detonation that might occur would be a very localized event, it is improbable that any equipment would be damaged in any case.

Additionally, the most likely location for a localized

detonation is in the ice condenser upper plenum, and th?re is no critical equipment located there. Last, it would take many widespread detonations to damage redundant equipment.

Therefore, no changes to equipment are required to prevent unacceptable damage from detonation.

Equipment List Table 8 provides a list of components inside containment that could be required to functicn after a hydrogen burn resulting from a small break LOCA.

Shutdown logic diagrams and safety function diagrams were prepared (with emphasis and detail on the functions occurring inside containment following the hydrogen burn) to determine the equipment needed for the event. The shutdown logic diagrams illustrate what functions must be achieved and what necessary or alternative paths may be available to reach cold shutdown following the event. The safety function diagrams provide ft ther detail of what must be available to achieve the particular safety function. These diagrams were then surveyed to identify the equipment located inside containment which would be required to function following the hydrogen burn. The emergency operating instructions were also used to determine information required by the operator and that required instrumentation was added to the list.

The diagrams and, consequently, the listing, do not include check

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TABLE 191 gg Category Justification of Category foT Equipment Function ,

)

LT-3-148, -156, -164, steam generator level input for '

H-1

-171, -172, -173 -174, control of AFW flow N3UE3

-175 (, g Containment pressure and L)

Air Return Fans 11 - 1 ggy_g hydrogen control H2 1-43-200, -210 Hydrogen analyzers H-4 All equipment is located in the annulus with sensing lines into containment.

Installation of ' flame arrester will stop propagation of flame to equipment.

FCV-43-201, -202, Allows air flow to hydrogen  !!-4 Valves fail open and loss of air to valve

-207, -208 analyzers ' will not affect closure.

FSV-43-201, -202, Allows associated FCV to open H-4 Loss of these valves will not cause

-207, -208 associated FCV to close. ,

Ice Condenser doors Allows steam flow through ice . II-3 Temperatures eue to hydrogen burn will bed have no effect on the doors. Require qualification for pressure only.

LT-t3-176, -177, Sump level for ECCS switchover H-1

-178..-179 FCl. .;'-172 Closed position' required for H-4 Not required to operate; must only proper ECCS flow path maintain closed position. All relays and controls for valve are outside containment. Hydrogen burn cannot cause the valve to open.

11 . -220, -355'. Pressurizer-level  !!- 1 TE-63-1, -24, -43,' -65 . Hot leg temperature H-4 The only equipment inside containment are the BTD's and cables inside conduits.

Lualification of cables in conduits will recolve these mensors.

Eculpment Function Category Justification of Category TE-68-18, -41, -60, -83 Cold leg temperature H-4 Same as TE-68-1, -24, -43, -65.

Hydrogen Igniters Hydrogen control H-4 Fenwal test data and analysis have demonstrated durability.

Core exit thermocouples Information for inadequate core H-1 cooling TE-68, -373 through For reactor vessel level system H-4 Same as TE-68-1, -24 -43, -65.

TE-68-386 FSV-68-394, -395, Reactor vessel vent valves H-1

-396, -397 Ice condenser seals Direct steam flow through ice H-4 Seals have been qualified for pressure requirements. Large heat sinks attached to seals will prevent damage due to high temperatures.

Penetrations X-003, .

Containment boundary, blind flange H-4 Penetrations have been qualified for

-111, -113, -112, -054, with 0-ring seal pressure requirements. Large heat sinks $'

-079A, -079B attached to the 0-ring seals will preven @i damage due to high temperatures.

Electrical penetrations Containment boundary H-2 Penetrations have been qualified for pressure requirements.

Airlock, Equipment Hatch, Containment boundary . H-4 Large heat sinks altar:hed to the seals and Personnel Airlock will prevent damage due to high tempera-Seals ture.

Containment Isolation Containment boundary H-4 The containment isolation valves will be Valves in the required position prior to any hydrogen burn. All air supplies will be isolated and all relays and controls are outside containment with only power feeds to the valves (i.e., the. valves cannot change position).

T Key for Tabic *EEE H Evaluation for pressure and temperature envi. c.ncntal qualification required.

H Eva'.uatica for temperature envirenr. ental qu?.itricatien enly required.

H Evaluatien for pressure envirennental qualificctien enly required.

H !!o further evaluatien required.

e i

and manual valves in piping systems since their function is not seen to be impaired by the hydrogen burn. Also,.the cables, splices, junction boxes, panels, limit switches, sensing lines, etc., associated with the listed equipment are also required (Table 9). All components of the instrument loop foi- the listed instruments which are inside containment and necessary to, or could prevent, the function of the listed co=ponents are also required, but not explicitly listed. Equipment-which needs to i function only very early in the event (i.e., before the hydrogen burn) and cannot later prevent the function of needec equipment is not listed in the table. The table includes equipment whose function is redundant to other required. Equipmeat whose function may only be desirable is.not listed.

The instrumentation and equipment are divided into fs'ar categories for evaluation of equipment survivability:

H Temperature and pressure l

H Tempeasture only l H Pressure only l

l H No further evaluation required t

Evaluation of Equipment

, Valves, penetrations, fans, junction boxes, cable in conduit, exposed cable, and instruments represent basic classes of l

components that have been evaluated to determine their ability to

~

withstand a degraded core event. Large equipment (fans, etc.)

t

- - . - . = .. .. . _ . . . . . - _ . ._ . - ~ .

i i

9 TABLE EE2 l

l Category H-1, H-2, H-3 components Required

Equipment for Equipment to Function i

LT-3-148, -156, -164, -171, Dirrerential pressure transmitter, sensing

-172. -173, -174, -175 lines, cable inside conduit, junction box

Air Return Fans Flow switch, sensing lines, cable inside l conduit, junction' box, electric motor Ice Condenser Doors Top deck blanket, intermediate deck doors, l

lower inlet doors

LT-63-176, -177, -178, capillary tubes,-dirrerential pressure

! -179 transmitter, cable inside conduit, junction box

LT-68-320 -335A capillary tubes, condensate pot, dirrerential-l- pressure transmitter, sensing line, cable

inside conduit, junction box i

1 Core Exit Thercocouples Exposed cable, cable inside conduit, junction i box i FSV-68-394, -395, -396, Solenoid operator en valve,- cable inside

-397 conduit,' junction box .

Electrical Penetrations Sealed penetration assembly I

6 i

1 1

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.i I: -

I l

1 .E-6

and containment boundary components, such as valves and penetrations, have esser:tially the same temperature response as the steel heat sinks. I..a Fenwal test data supports the analytical results, as it showed temperature rises in the 1

equipment and the test vessel w'11 were approximately equal and that the rises were modest for all bus very small components (i.e., thermocouples). Large components can survive a degraded core event without damage. Exposed cable tested at Fennal showed minor damage for certain types of insulation. The insulation was not sufficiently damaged to degrade the cable; however, modification of exposed cable inside conta."nment may be needed.

Further testing of cabling will supply the informatien necessary to determine changes that may be required. Our evaluation indicated that cable in conduit is protected from hydrogen burns. Fenwal test data supports this conclusion. The tested "

samples of instrument boxes indicated temperature rises that were less than the temperature rises indicated by the analysis of the steel heat sinks, supporting previous statements that dama6e to instrumentation from a hydrogen burn was unlikely. Because instrumentation and, in particular, the electronics are more sensitive to temperature changes than most components, TVA is committed to a program over the next year that will provide additional information on the effects of the temperature on instruments. !rcul: ting Insulation does not appear to be required for any equipment other than exposed cable. However, because it would be so effective in reducing temperature rises, it is being seriously considered for instrumentation also. TVA is also evaluating relocating instruments on steel heat sinks to

APPENDIX C COMPARISON OF POST-INERTING AGENTS Several post-inerting gas systems have been examined for use at the 7equoyah Nuclear Plant during degraded core events where significant

(;antit ies of hydrogen may be produced. The post-inerting schemes rely en the introduction of diluent gases or explosion suppressants

'during the accident, based on QQgrator judgement concerning the extent of core damage. Agents examined include Halen 1301, carbon dioxide, and nitrogen. Inerting is acco=plished by increasing the partial pressure of nonfla=mable gases and hence their volume fraction in the mixture while reducing the volume fraction of oxygen in the mixture.

Halon represents a special case since the gas acts to inhibit the deflagration chemical chain reactions during the burning process and therefore less Halen is required to prevent burning than from a simple diluent process. Unfortunately, in all of the post-inerting processes the oxygen fraction is depleted by adding non-oxygen bearing gas to the system, consequently increasing the containment pressure.

Thermodynamic and chemical properties of the commonly _ used iner ting agents are shown in Table C.1. At normal temperatures and pressures, each of the agents exists in the gaseous state. Carbon dioxide stored for fire protection is under pressure and refrigerated (300 psi, O F).

Once sprayed into an enclosed space, the carbon dioxide liquid becomes a vapor and snow mixture which then sublimates, absorbing energy from the atmosinere in the process. Halon is also stored as a liquid under

i I

pressure and the necessary latent heat of vaporization is available '

from the containnent air / steam mixture. Nitrogen can be stored as either a cas or a cryogenic liquid.

National Fire Protection Association (NFPA) Standards reco= mend that a Halon vapor vencentration of 31 percent by volu=e be used to prevent hydrogen detonaM0n er deflagration for any hydrogen concentration.

This is cc$servative when compared to inerting Halon concentrations of 20 percent by volume generally accepted as adequate for Halon inertinc of hydrogen atmospheres. Analyses performed for cr.parative purposes have assumed the 31 percent value.

Table C.1 Properties of Inerting Gases p Halon 1301 Carbon Dioxide Nitrogen Composition C Br F CO N Molecular Weight 3 2 148.91 44 01 23.01 Critical Temperature 152 7 F 87.8 F -232.87 F Boiling Point (1 atm) 57gpsia 1057.4 psia 492.2 gsia Freezinc Point -72 F subliptes -320.3g F Heat of Vaporization -270.4 F -109.4 F -345.7 F Vapor Pressure 'f 7.7 6%/16. Z%.J ON/llm S S.7 Otu / b (Sat Vapor at 70 F) 213 7 psia 800.0 psia -

Vapor Density (60 F, 14.7 psia) 0 392 lbm/ft 3 0.1159 lbm/ft 3 0.0737 lbm/ft 3 Specific Heat 0.205 Btu /1tm 0.249 Stu/lbm Thermal Conductivity -

0.00952 Btu / 0.0149 Btu /

(ft Ib F) (ft Ib F)

For P "rting via nitrogen or carbon d. oxide, Bureau of Mines data has been used which indicate that approximately 61 percent carbon dioxide or -

in de (i.ul mhiure l ty colu e--ead 75 percent excess nitrogen by volumeAare individually '

adequate for inerting atmospheres with any concentration of hydrogen.

Calculations using the above concentrations indicate that the partial pressure of either nitrogen or carbon dioxide is exce.sive whereas the

r use of Halon does not result in unreasonable ice condenser containment / pressure loadings. Results for an assumed containment temperature of 240 F are shown in Table C.2. More importantly, the ratios of the partial pressure of nitrogen and carbon dioxide to that of Halon required for inerting are also shown. These ratios are independent of temperature. It should be noted that if a lower concentration for Halon inerting (20 percent by volume) is used, then the results for nitrogen and carbon dioxide become even worse in comparison to Halon. Based on TVA's preliminary studies, both carbon dioxide and nitrogen post-inerting are not being considered further for application at Sequoyah.

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Table C.2 Partial Pressure Results for Post-Inerting

-Assume: - temperature = 240 F

- hydrogen release equivgleng to 75j metal / water reaction

- air volume = 1.19 .* 10 ft at 60 F, 14.7 psia

- ratio of nitrogen s 'ume/ hydrogen volume required to inert =17

- ratio of carben dioxide volume / hydrogen volume required to inert:10 5 Inerting Gas Partial Pressure Carbon Dioxide 47 psia Nitrogen 76 psia Halon 11 psia Ratio P(CO2 )/P(Halon = 4.3 Ratio P(N2 )/P(Halon) = 6.9 l

1

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