ML20128N237

From kanterella
Jump to navigation Jump to search
Preliminary Idcor Task 23.1 - Integrated Containment Analysis
ML20128N237
Person / Time
Site: Sequoyah, 05000000
Issue date: 06/30/1984
From: Henry R, Mims W, Mitchell H
FAUSKE & ASSOCIATES, INC., TECHNOLOGY FOR ENERGY CORP., TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML20127A894 List: ... further results
References
FOIA-85-110, RTR-NUREG-1150-2-V2-C.4.09 NUDOCS 8507130064
Download: ML20128N237 (142)
v • d • e


Text

{{#Wiki_filter:oh ' ,)nO ~ g;,; ) '5

ac0w. :C::.:Az st.uC n >f)ft v

3 sc 5 a DOOK TiST. 23.1 - OCIOR.CD CO CA2iXCC A.;A*.!!!3 ~: ; ".;c~9 I , p g,'y,u\\.n,'j d # d'. n, \\g GV V Prepared by: h"

x d e * "'g.

..x William. F -=, Jr. .w.. : t : r,.=s,,P' ##~ ~; John W. McAdoo .. z. s. W.: x Chr:,,s Carev s&=We Teung H. In Stan C. The=as 7:ank A. Kcon::, Jr. Tennessee Valley Autheri:7 Rober: I. Henry Marc A. Kenten Rny W. Mac Densid Fauske and Associates', Inc. 5 Ezrcid Mitchell Technology fc: Inergy Corporazion Dirk S. Leach Westinghouse Electric Corpora:ics Rober: D. Burns CS Nuclear, Inc. June 1984 (9 IfD 4 050413 0 ALVAREZG5-110 PDR .=.- DCOR.70 //9

J e r- @ g " 9 TA31.E OF CON 7"fCS o r.C Acknowledgement h Abstrset .. y,.e JM "' Executive S -ary

  • ,Q
    ).ll :. gj5*W Seetion gs Pace

.7 1.0 Introduction....................... 1.1-1 1.1 Statement of the Proble:n...........,.. 1.1-1 1.2 Relationship to Other Tasks. 1.2-1 2.0 Strategy and Methodology..... 2.0-1 3.0 Descriptions of Models and Major Asst =:ptions. 3.0-1 3.1 Plant Description. 3.1-1 3.1.1 Reactor Coolant Sys te:n Description 3.1-1 3.1.2 Reactor Core 3.1-1 3.1.3 Reactor vessel 3.1-3 3.1.4 Stes: Generator.............. 3.1-4 3.1.5 Reactor Coolant Pu:sps........... 3.1-6 3.1.6 Pressuriser................ 3.1-6 3.1.7 Contain:sent Description. 3.1-7 3.1.8 Contain:nent Heat Renoval Sys tes. 3.1-16

3. l.9 Emergency Core Cooling Sys tem.

3.1-17 3.1.10 Auxiliary Feedvater Sys ten 3.1-20 3.2 MAAP Code and Input Model Description. 3.2-1 3.2.1 Primary System Bodali=ation 3.2-6 3.2.2 Contain:sent Noda11:ation. 3.2-8 3.3-1 3. RETADI code In t Model Descript n 3. Tis on Product elease om Malting F 3.3-1 3.3. F' sion Product Re eas from the Core Interaction with crate

3. -3 3.3.3 Fin on Product Re as free Continuing 3-3 Int m etion vi Coner
a.........

3 .4 Tis sion hodue.ransport. 3.. 3.3 - .3.5 Reference 4.0-1 4.0 Sequences Analyzed. 4.1 Sequence No.1 - S D

  • * * * * * * * * * * * * *
  • 4*l~l 2

4.1.1 Accident sequence Description....... 4.1-1 4.1.2 Reactor Coolant System Response 4.1-1 i IDCOR.TC

, g ~. r. - FC TABLZ OT COT"IM"'S (Cantinund) ,M, .M

  • ~,.;
  • s
q. g

, w-b 7 4.1.3 Contai:nnent Response - I:nmediate Rel' ease " ~ of Volatile Fissioni Products ,,._4 . 4.1-3 4.2 Sequence No. 2 - S H * * * * * * * * * * * * * * *

  • 4*2~1 2

4.2.1 Accident Sequence Description...,...:... 4.2-1 4.2.2 Reactor Coolant Sys tem Response... . 4.2-1 4.2.3 Containment Response - Insmediate Release of Volatile Fission Products........ 4.2-4 l 4.3 Sequence No. 3 - 5 EF............... 4.3-1 2 4.3.1 Accident sequence Description . 4.3-1 4.3.2 Raastor Coolant sys tem........... 4.3-1 4.3.3 Containment Response - Immediate talease of Volatile Fission Products........ 4.3-2 4.3.4 Reactor Coolant Sys tem Response . 4.3-5 j 4.3.5 Containment Response............ 4.3-6 4.3.5.1 Immediate Release of Volatile Fission Products................. 4.3-6 4.3.5.2 Retention of Volatile Fission Products in the Primary System............ 4.3-7 s 1 4.4 Sequence No. 4 - TML3' 4.4-1 i 4.4.1 Accident Sequence Description . 4.4-1 j 4.*4. 2 Reactor Coolant Systen tesponse 4.4-1 4.4.3 Cont ainment Res po ns e............

4. 4-2 l

4.4.3.1 Immediate Release of Volatile Fission Products................. 4.4-2 4.4.3.2 Retention of volatile Fission Products in l in the Primary Sysces.......... 4.4-4 xL.............. 4.5-1 4.5 Sequence No. 5 - T23 4.5.1 Accident sequence Description Reactor Coolant System Response 4.5.2 Containsent Response - Immediate de[ ease of l 4.5.3 Tolatile Tission Product.......... 4.5-2 4.6 Sequence No. 6 - AD................ 4.6-1 l 4.6.1 Accident Sequence Description 4.6-1 4.6.2 Reactor Coolant System Response . 4.6-1 i 4.6.3 containment Response - Immediate Release of i Yolatile Tission Produce.......... 4.6-2 1 1 -li-ID001.TC l l e

~ .bg'I gt ,p ' T8L3tI 0F CONTIN *S (Continued) p,C 7., {\\ ~ ,V g\\$@\\$'6 g , ILLCSTRATIONS .. :-W:e' p - 7itu;e ~,

fu,, r.g,' '
. :y&"

^ 3.1-1 Cross Section of Reactor Coolan: Sys Ea$$$$'PY.. 3.1-2 W 3;1-2. S eems Generat or Cutaway....... '. -...... 3.1-5 3.1-3.. Containmen: Cross S aiion. 3.1-9 p 3.1-4 Con:ainment Cross Section.. 3.1-10 3.1-5 Con:ainmen: Cross se:: ion.............. 3.1-11 3.1-6 Containmen: Cross Section.............. 3.1-12 3.1-7 Ice Condenser Cu:avay................ 3.1-13 3.1-8 Rase:or Cavity Cucavay ~.............. 3.1-15 3.1-9 Emergency Core Cooling Sysess Tiow Diagram 3.1-18 3.2-1 MAAP Primary Sys tem Nodalization... 3.2-7 1 3.2 2 Ice Condenser Containment Nodalization....... 3.2-9 -- t *4 E.A 5 k awai =.aw awa."l..:ier - .?*' 4.2-10 S R Eydrogen Burn Duration 4.2-1 2 4.6-1 Core Temperature Nap 0.00 Hours.......... 4.6-4 4.6-2 Core Temperature Map 0.10 Hours.......... 4.6-5 4.6-3 Core Temperature Map 0.60 Hours.......... 4.6-6 ' 4.6-4 Core Tamperature Map 1.60 Bours.......... 4.6-7 4.6-5 Core Tamperature Map 1.70 Rours.......... 4.6-8 4.6-6 Core Tamperature Map 3.00 Hours.......... 4.6-9 9 '-5 =5.1-1 H-i - 5 g ;2: -?[ 51* 7.swiaA mes cor.1.. ;f Isj..:i;;. - 5 ? ^ $^# 2 5.1-4 4ri-5 rarcial Restorar. ion si.uj.;;1er

  • ?

5.1 ? y -1 iarcial Restoration a:.aja..lw. ?g5 v IDC01.TC

% a 9 J TA3LE OF CON"'ESI*S (Centinusd) 1<~ O P ec ~ . _..y , ; J '~ c

C.

.o ..y

z. -

hfb~ T. ABLES Table . Pare .. ;. : p 4.0-1 Primary and Con:si=:nen: S ys ta= S ta:us 4.0-2 4.1-1 5 D Even: Summary........ 4.1-5 2 4.2-7 4.2-1 S E Even: Summary. 2 4.3-3 S EF Even Summary (F3MAAP). 4.3-9 2 4.4-3 'DC.B ' Even: Su=nnary (74MAAP) 4.4-9 4.5-1 T23E Event S ummary...............

4. 5-4 4.6-10 4.6-1 AD Even Su= mary 7
7. -1 TMLB VWi:h A Sea LOG (Case 1 7.1-5

\\ th A Se LO (Case 2) 9 7.1-2 'DC.B / ' - With 7.1,-10 B Seal LOG (Ca 7.1-3

7. -1 5

- (Case 1). . 7.3-2

7. -2 5 EF ase 2)

.3-4 2

7. 3-3

- (Case . 7. -5 / /

8. -1 5

ry of Se en s 8.1-5 Eigh Se ah Release celans Com 8.4-with WW1400 Results /.... pars. 4-2 / IDC01.TC e w. 4

s. u. L G I t_ c TA3!.E CF'05.C r5 /Ccc:inued) e Disclai::e s ?is verk was prepared.by the.Tsunessee 7 alley Au:heri:y, in part, fe use by the A:c=ic Industria.1 ?cru= i Nei:her :he Te==essee Valley Autheri:y, the A:c=i: I=dustrial ?cru=, nor any of their e=picyees, =akes a=y warran:y, exyressed cr.i= plied, er assumes' legal liabili:7 c: responsibility for the accu:acy, c e.~.::ple:eness of any infer =atic: cos:a:.ned :..s th:..s reper.- l @l f +,. t. a o '1b \\bo n}eg;.4 g \\\\ . s.;,., , + ~ / ..+ ....,.< **.*. 3.: >Y, -:p ... ~ ,a p Tbkh. ~ Q,. \\ f f. 's t 6 s = . v t \\ n IDCOP..TC e' v...-.- - - - - - - ~ - '

s .., ;..- r _ mn e_ c;. en.i _ _....e. ( wo-.. :.s e d ),- p,, - e l s< A knev1edee=en: he authers and cc : ibe:::s wish := ack=:vledge the '.effe :s....of several i=dividuals i: the p eparatic: ef :his reper:: Messrs 1,.

  • a'.

Lau, 7.

7. Christie, and D. G. Re.fre for =anuscrip: review; Messrs 7.. D. Kei:h a d M. L. Miller for input da:a retiew; and the NI3

- seere:arial staff fc: =anuscrip: :yping. In addition, cu effer:s and

ibula:icas have benefi:ed f c= disenssien virh Mr. I. 7811er the
  • DOOI phe===e= ology =anager.

e 9 m M .GW s 4 me..

== W m 9 9 211 3,.n o.. mwbwhoeb

.g e rv:n i 1.0 Introdue:ien

1.1 Statemen

of the Proble= ne =ain objective of this investiga: ion is to calculate the ther=al y.x e #3.. ;.:5.95'* hydraulic and radiological response of the m n=esie,e Valley Au:hori:v.'s Sequoyah Nuclear Plant primary system and cen:ainmen: for postulated severe accident sequences, i.e., those which have been iden:ified as These sequences potentially leading to core degrada: ion and melting. will be addressed on a more realistic basis and vill include assessments of the majer uncertainties associated v-1 h s:ste-of-the-ar Also, the s:udy vill include assess =en:s of the results of modeling. operator in:erventien in these sequences along v-ith the influence of could be considered for specific addi:ional _itigating features tha: Similar studies have been performed for the Sequoyah Nuclear Plan:. three other reference plants: Zion, Grand Gulf, and Peach So om. The results of the containment analysis are incorporated into an assessment of the fission product release and deposition within the For those sequences in various regions of the con:ainment building. which containment integrity is violated, the release of fission is calculated and included in products to the surrounding environment an evaluation of the potential health effects associated with the In this regard, the influence of the specific accident sequences. specific additional mitigating fea:ures is also addressed, in a different IDCOR subtask, in terms of the effective risk reduction provided by these. features. 1.1-1 IDcoE.1

m. , g.y [. t*. s,'>- 3 y. M E. ' y' 4 a ' '

1.2 Relationshi

to other Tasks rs I-G.

  • Se centai==en: enalyses of IDC01 Subtssk 23 a e dependent upon the pri=ary systen and containmen: response models developed in Sub:ssk 16.2 and 16.3, 'Tsecutive Analysis Prog:sm,""(Ref erence 1.1) cud the fission product release, transport, and re:en: ion =odels developed in DCOR Subtask 11, " Fission Produe: Behavior"' (Icf erence 1.2). ne dominant accident sequences used for the analyses along with the operator interventions were developed by considering :he relevan: or key acciden: sequences presented in Subtask 3.2 (Reference 1.3).

The ul:imate s: uctural capabilities of the reference plan: containments and other typical designs were assessed in 2001 Subtask 10.1 (Reference 1.4). These analyses define the contai= ment failure pressure and failure mode assumed in this analysis. Ter the Sequoyah containmen: this failure was identified as a breach at the containment spring line. Calculations of tha rate and amount of fission products released from the containment, for those sequences which result in centainment f ailure, were supplied to DCOR Subtask 18.1 (Reference 1.5) to formulate assessments of the health consequences associated with these postulated accident sequences. These health consequence analyses were i then supplied to DCOR Subtask 21.1 (Reference 1.6) to evaluate the risk redue: ion potential for possible additional mitigating devices considered for the Sequoyah Euclear Plant. DCOR.1 1.2-1 w, -++==-+ em .= w o- ,y ---m w v e*--*--

r g ,, e _.. M. $ dd"O

c. p..a. \\ -

Potential operator interventions were developedjan: Fha,.ps e. .v pplied to the .p specific a=:iden: sequences in the Sequoyah analysis to de:sr=ine those M'" potential actions which could ter=inate the acciden:Isequdice,.y.=G,~~ ..g.v..-x: . - s and $kSOSW result in a saf e.s:able state. This was considered as part of IDCOR Subtask 22.1, (Ref erence 1.7), "Saf e Stable S tates," which discus ses . potential means of terminating the various core da= age sequences considered for the Sequoyah Nuclea Plant. Finally, it should be noted tha: the analyses developed as part of IDCOR Sub: asks 16.2 and 16.3 involve the detailed consideration of many different phenenena which are the=selves considered in separate IDCOR sub: asks. These' include: hydrogen genera: ion, distribution and combus tien (12.1, 12.2, and 12.3), s tea = generation (14.1), core heacup (15.1), debris behavior (15.2), and core-concrete interactions (15.3) as discussed in Reference 1.1. Detailed discussions of these topics can be found in the final reports subc:itted for that specific task. Individual issues vill only be addressed as required to understand the specific behavior obtained for the acciden sequences considered and the specific design characteristics of the Sequoyah Nuclear Plant. IDC3R.1 1.2-2

o s ,,,. x.,. O,Le f.ss\\, W pt \\, '",,g i ; 1,, s. 1.3 References i g \\Y\\\\\\$"' .,y : ' . ;.u> 1.1 "MAA?, Modular A::iden: Analysis ? cg z=," Technical lepert,ce COCOR Subtasks 16.2 and 16.3, June 1983. ,, hid;Mf,.g#p pr. i?.Whp d p y,+ 1.2 " Fission ?:odue: Transper: in Degraded Core Accidents," Technical Repor: on IDCOR Subtask 11.3, December 1983. 1.3 Technical Report en !DC01 Subtask 3.2. 1.4 Tech =ical Report on IDCOR Subtask 10.1. 1.5 Technical Repor: on IDC01 Subtask 18.1. 1.6 Technical Report on IDCOE Subtask 21.1. 1.7 Technical Report on IDCDR Subtask 22.1. e +e e eee IDC01.1 1.3-1 i e ~ ~ ..-..e n. w.

.S 2.0 Straterv and Methodoloev The basic strategy is to analyze some of the relevant er ke sd i" dent _c, .\\ \\H C ,i sequences leading to a degraded core sta:e. Theselsfa1 sis' wiM first 7 consider whe:her such sequences lead :o core =colvery(and dc= age and ~ @ 4.( 'l

c. /

~ \\ u then de:er=ine the progression of the accifeEt for those sequences;in' w' :- .which core degradation and melting is calculated. ;This;4nal}' sis n ~c +.- Q @ includes the performance of the emergency edreTooling sys tem and the containment engineered safety systems, such as the upper head injection, ice condenser, contain=ent sprays, hydrogen igniters, residual heat removal sys te=, etc. The methodology used in these analyses is the PWR-EAP computer code developed within the IDCOR program as Subtasks 16.2 and 16.3 (Raference 2.1). This code considers :he major physical processes associated with accident progression including hydrogen genera: ion, steam formation, debris coolability, debris dispersal, core-concrete interactions, and hydrogen combus: ion. The calculations for primary system and containment response have been evaluated for each of the key accident sequences. Core and containment temperature, pressure, s team condensation rates, and flow rates were used to assess the fission product release rates from fuel and the ef fect of core-concrete l interaction on fission produe: deposition and release for each sequence resulting in con:ainment failure. The containment conditions have been supplied to the EITAIN code to de: ermine the retention of fission - -- poducts wi:hin the primary sys tem and containment (Refere$ce 2.2). j ~ This provides quan:ification of the relative amounts of materials deposited on cold walls within the contai= ment, within the ice bed, and l IDC01.2 2.0-1 l j .w-.

o thoco which would be expacted to be t=hausted through any breach in tha 6\\ reactor building contai=nen: boundary. This calcula%ien $h'en provides $ ed ' the ti=ing, a=ount, and rate of release-ofAhe radienu:lifes which are \\1 ' further considered in Subtask 18.1 (lef e~rences.2). 7cr ez:h ac:iden: sequence, analyses were carried out considering three potential =edes' of fission product behavior af ter release from.:he fuel =at-iz. These ~ include the assumption that either al1 volatile fission p oducts and noble gases are released from the primary system at the time of reactor vessel failure (point A on Figure 2.0-1) or that these fission products are retained v'. thin the priscry sys:em with their potential release being governed by the subseques: hea:up of the structural =a:erials and the flew be:veen the primary syste= and containment (point 3 on Figure 2.0-1). This spectru= of condi: ions represents the uncertainties associated with the dynamic processes accompanying f ailure of the. reactor pressure vessel. For the cases in which the vola:ile fission products are retained within the primary system, the heatup of the reactor vessel and its structures is evaluated through the CIRC code natural circulation model. This model was incorporated into 2ETAIN to evaluate the subsequent fission product behavior and transport as a result of density driven flows. As part of this evaluation, the MAAP code containment pressurization was imposed upon the primary system, and this determined the magnitude of flows between the primary system and containment. - The cases in which the fission products were retained in :he primary system were further subdivided into two situations. The first assumed that the cesium and iodine were combined as cesium iodide rlth the IDC01.2 2.0-2

-. s t 4 W,7 't Dr(M* la y c.'t.\\ 'b C \\r ' ' tr ~ r l l .l l I I I id g i g I I i g 2 s-I .,... f.i d * I i ,. j d'I hM y~r .. s.+~. l t l h"l l I

==-" t I _ _ Qy.' l.j d l I i s l = 1 1 .3WE4 f 9)# I i hM i l I l i S i l / -?,! l i i i i I g e d I i I T h:=alt l i 3 li jlg s 3 i g

ui i

i e 3 i '".=&g W-. i I i I i 2 lji I I i i W 1 1 m g l C' i i C l i 14 5 I i 1r" 3 i i<- i l i. l i i i I i 1 i l l 1. si s i u fis i i i i i = x j _m_. e _ _ i, __.; i i i i i i s -s i i el i i = .r i o ,. w:2.. i v i = i i t i e.i t pL = u ng-5 i i . w. i i m p.n mi i 3 $l i I di 3 3

  • 3 C

E, i .==a. i z - - i, H l l i i j Gli E e s i i i I o i i i i i i i 3. i i r-- W O i I i i FJ

s i

.I, i m

. iu i

l i i

g i. : :.

f 8 i i i i i i u i f s. g i i i i 35 i i s. i 1 41,i 1 i i i. i. l i. i m _4 I i i i i i, i 3 i i i _. d...i f-i i i i i i re i i s e

~3' i

t i r 3 i i i i 3 I 1 l di i i I i I l i i 3 I I i i i i l 1 i I i i I 1 i i i I I i g g .i 7,. -- 8 i 8 i I I I I i 1 l l l.l l-I l=! i,. tr.s 11.= e_, :.w..;tl, 4,i i:l :n.45..j: x i s., i-x i ,,22l;,s.z.s.2 3 J,2. i s;s'j $ g i it: aa i :I;3; 28 s gs-1 3.=. :. 2 i._3 = i

remaining casium being bound as cesiu= hydronide. In this 1sassrsant, 6 4 % b designated as point C on Figure 2.0-1, both the,%.,=I16didek.0,'.\\a ahd cesi.:. s cesium hydren.de were assumed to have a vapor \\p.)\\\\ \\$\\higus in\\Dregsnee equal to that M' ,P specified for cesius iodide in Reference 2.3. The second evaluationi."n..s.. ..N.

e. Rip.<~" g ;*

(poin: D in Figure 2.0-1) asse::ed that the deoosited :ces ~u="and iodine NQV.' would reae: with stainless steel surf aces with*:.I.the pri=ary sys tem and become tightly ~ bound to the' surfaces. This chemical bonding should reduce the. vapor pressure and minimize mass transport. In this assessment, the materials were assumed to have the vapor pressure of iron. With this assu=ption, the subsequen: heatup of the primary system was d.2:er=ined and if the original fission product deposition resulted in melting of the structural ma:erials, these =aterials were then added to the coriu= deposits belov the reactor pressure vessel. Figure 2.0-1 also. indicates evaluations rela:ing to both containmen: bypsss' and failure to isola:e acciden: scenarios. These are reported under IDCOR Task 23.5 (Reference 2.4) f or all the IDCOE reference plants and are not discussed in this report. Several si=ulations of the primary system and contai= ment reponse include features other than the currently-installed saf ety sys te=s. These simlations are par:ieularly important in deter =ining whe:her specific accident sequences indeed lead to core damage when all available plant sys tems are credited and can be of considerable importance in determining the potential for establishing a permanently coolable state. IDCOE.2 2.0-4

  • ' ~ ' '

^**-- .m,._,_.

e, For occh of th2 cecident scenarios selected for analysis, the sal- . hydraulic calculations were performed bo:h with and withou: opera:or intervention dr ing the a=:ident. The " base case" analyses, which as su:ne only =ini=al opera:cr reponse dri=g th'e' a=:ident, es:abl,ish a j reference sys te= response dring each of the a :idenY scenarios. The " operator action" analyses are branch calculations of the base cases. These operator intervention cases de=enstrate the effect of a ' realistic operator response on the progression of an acciden 'and provide a measure of the time available to the opera:or for such action. Uncertain:7 and sensitivity analyses have been performed on several key parameters associated with the a :ident respons e. These are. reported in Reference 2.5. In the analysis of the containmen: response for the ice condenser systeci wo features have been observed to provide subs tantial accoc=nodation for energy deposition and fission produe source terms for a wide range of acciden: scenarios. These are the igniter systen for hydrogen ec=bustion a: low concentration levels and the ice I condenser which condenses steam released frein the primary reactor coolant system. The igniter system is modeled in te=ns of the ac:nber of igniters and their location throughout the containment compartments. DCOR. 2

2. 0-5

7cr ths Sequoyah Nuclec: Plant, the ice condensar has a do=inent i influence on the accident progression frect savaral different response characteri=ations. Tirst, overpressurization of the containment by. - 'mN', s t es=t can oniv occur if the ice bed has ce=pletelv meir%9..whi'ch". g.43 .d.J' )). requires' subs tantial energy deposi: ion and i.ifIdd.nMb...N:@renoval L the residual hea: reoval sys tem and contai=nen: sprays. S econdly.,, the...,j, q'% w =* &* n ::- w total vatar inven:ory in th'e lower compartment,and. cavif.'. Oil 5%ueich gm..... -: g,wT. - . Mists the core debris which would lead to core-concretT attack if not covered. Las tly, the ice bed can retain subs tantial quantitic. of fission product ma:erial, specifically cesiu= and iodine, which would be los: from the fuel during a core =el:-down event. All gases evolved frcan the vessel vould be forced t'..roug'.. the ice bed to the upper cocrpartment either by differential pressures or by the air return fans. These ' features are included in the integrated MAA? and RETAIN analyses carried out for the Sequoyah Ruclear Plant. These vill be presented in the following sections starting with the description of the plant and its sys tems, the accident analysis models and the major assumptions associated with the models, followed by the plant response, recovery actions, and the influence of selected mitigating features. G e. IDC01.2 2.0-6 n-+- n.

2.1 References uy .j ...,v.udu 2.1 "MA.A?, Modular Accident Analysis Prcgrn,)UsdVRanual," Techni:al $2 Report en IDCOR Tasks 16.2 and 16.3, May 1983. = e en ..,, u.- . pG D.'._ PAG #q, W ...4 2.2 Technical Report on IDCOR Task 3.2. s ~' ' i 2.3 " Estimation of Fission Product and Core-Material Source Characteris-tics," Technical Report 11.1, 11.4 and 11.5, October 1982. l 2.4 Technical Report on IDCOR Task 23.5. 2.5 " Uncertain:y Analyses for Modeling Approaches Used in the NAA?-B*at and MAAP-?WR Computer Codes," to be published as an IDCOR report. DC01. 2 2.1-1

'O s 3.0 Dese-i >eien of Medels and Ma _ier Assu=stions ""his section of :he reper: describes the plan: model and =ajor ~ assumptions used in the !0CCR Task U.1 analysis of~.he, Sequ'oysh-p1an: 8 g e .r P using :he MAA?, FPRAT, C!RC, and RETAIN cedes. g g tg,dUy G u uu u M g! 3.1 Plan: Descrietion p;/:.M m...n.. . - ic aw.-. -. v ,ggggg+g_ j,.2,.....wh ;; a-ddice' The Sequoyah Nuclear Plant is a two unit plant eonsm.ng or 'Jestinghouse-designed reactor coolant systems with a raced thermal power of 3123 M'J:. An ice condenser pressure suppressien containment is e= ployed along with several other unique plan: systans and features that deter =ine the overall thermal hydraulic and fission prec:.::: respense charac: eristics to degraded core events. As a basis for understanding the resul:s presented later in this report, a description of :he important geometric and system details is given in the following section. A review of the salien: features of the MAAP, 77 RAT, RETAIN and CIRC codes is then presented in conjunction with a discussion of input parameter de:erminations j IDCOR.3 3.0-1 n m $e A+q-ma 4-4, we ww.m_y-

  • --4 3yreae a e

+4.-moQ s-me=.R =e pe Mg - een.e

3.1.1 Reseter Coolant System Descriotion The Reactor Coolant Systam censists of four si=ilar, heat transfer ~ loops connected in parallel to the reactor pre'ssure 'vesseJ. ' EachYoopd yo-contains a reactor coolant pump, steam generator, and associated piping. In addition, the system includes a pressurizer,- a.pressurizeri ',

  • A1.1 ':hhe4boire Tom,g.;;41-."

"'~ ' %t:d {7e.-3 5.0 relief tank, and interconnecting piping. ponents are located.in the containment building. Figure 3.1-1 indicates a typical reactor coolant loop cross section. The high elevation and U-tube design of the steam generator creates the potential for condensation refluxing and countercurrent hot leg flow during sequences with inadequate primary system makeup. 3.1.2 Reactor Core Two-hundred sixty-four rods are mechanically joined in a square array to form a fuel assembly. One-hundred ninety-three assemblies ~ make up the Sequoyah core. The fuel rods are supported at intervals along their length by grid assemblies which maintain the lateral spacing between the rods. The grid assembly consists of an " egg-crate" arrangement of interlocked scraps. T-straps contain spring fingers and dimples for fuel rod support as well as coolant mixing vanes. The fuel rods consist of slightly enriched uranium dioxide ceramic cylindrical pellets contained in Zirealoy-4 tubing which is plugged and seal welded at the ends to encapsulate the fuel. A total mass of 222,645 lba of uranium dioxide is used in a typical fuel loading. The approximate Zircaloy weight of the fuel assemblies is IDCOR.3 3.1-1 ~ ~ .__n -.i-~ ~

.- - =..._._ _.. 'o A* e a w 5: e ~~^._... - iii.ih m l -- %]g l'E '.,- c r.-.,E % ~ _ ^ '

_s-..a x

j -- [,# 1 W m l i Qf;5=Qi,:k* 6YE *Y I 5 d I' z ,I e Q = e t 25 = ~ u ~* = 'b-3$ u ~ W W 8 d 5 W= u g a. v. - 57 U V: N 7 5 5 & gg 2 s ( _Q = mum:== % } a. e = w 2 \\

  • 5

>2 5 ', z \\..w

==

"2 s.c.. 3 s. ~ - U3 lC k "N % I N e W sw w'. = -._.u--- c$ J E t w. y I-J / f 58 I w (: \\ QI s W 6.- \\ 's i w V = 5 5 v = i u a B. w i i v. l 5 5 e p;;;:3 ' JJ j y ."g N =7 = as I ~ k l a i p .? ~ l I NI l $:e I. .w i i 4 j % I ~ k. .f l f hi U * "M"*""""" l l I O! / i p~., m -s 1 j' i f (" r w w 5 e-eI 8 8 S e M ~ T a. >= - a w E188* j i . lGURE 3.1 1 CROSS SECTION Oi: REACTOR COOLANT SYSTEM 3.1 2 w e. w m. rw. - - ,,.__,,,,_c --..,-,,.,y, ,,,,,,-,....__-,,-,,,.,-.,,ym,. .,,.,,-.,-.-%.,__,,-__.,.,,-,,-._--,rgy., '" * ~ n,, ,,,,m,-,.,--.,.._,y,--- -y,.-

      • F*
    • sw..,g, r

-w

47,000 lbm. Potentially, complete exidatien of this :ir:eniu= could result in the release of over 2000 lbm hydetgen. All fuel rods are pressuri:ad with helium during fabrication. 7:' '. _.,. - ____>y v. The core is cooled and moderated by light water se-a" pressure of 2250 lb/in2 The coolant contains boron as a neutron poison. 3oron a is varied as required to control' 3g" ;y.vC ;* ' concentration in the coolant ,, ;. x - relatively slow reactivity changes including the effects of fuel burnup. '"he control red drive mechanisms are of the magnetic latch type such that upon a less of power to the coils, the red cluster control assembly is released and falls by gravity to shutdown the reactor. 3.1.3 Reactor Vessel The reactor vessel is cylindrical with a welded hemispherical bottom head and a removable hemispherical upper head. The reactor vessel closure region is sealed by two hollow metallic O-rings. The vessel contains the core, core support structures, control rods, and other parts directly associated v.th the core. The reactor vessel closure head contains control rod drive motors (CRDM) and upper head injection (UEI) adaptors. The bottom head of the vessel contains penetrations for connection and entry of the nuclear in-core instrumentation. Each in-core instrumentation tube is attached to the inside of the bottom head by a partial penetration veld. It is this weld that is projected to fail under corium attack for. the Sequoyah vessel. IDCOR.3 3.1-3 .e+

7. s .3.1.4 Steam'Generater e "'he steam generator is a vertical shell and U-:ube eyaporahwfch'.. E'?.$? assG.nd(C'@'""g.ir2.#.\\e 'yigurs The integral =oisture separating equip =en: h$\\ reae:ce coolan flows through the inver:ed Ug;:ches7 entering and leaving through the nozzles located in the hemispherical bet:cm.headj.U'.cah s -c; #.. .... "' c.'5-!&v g .o! ME A -of the steam generator. 'QQil$k tyr Feedwater at approximately 43007 flows directly into the annulus formed by the shall and tube bundle wrapper before entering the boiler Subsequen:1, water-steam mixture section of :he steam generator. 7 flows upward dreugh the tube bundle and into the steam drum section. A set of centrifugal moisture separators, located above the tube bundle, removes most of the en: rained vecer from the steam. Steam dryers are employed to increase the steam quality to a minimum of 99.75 percent (0.25 percent moisture). Recirculating flow from the moisture separators mixes with feedwater as it passes through the annulus formed by the shell and tube bundle wrapper. Steam exits the generator at 857 lb/in2a with a.flowra:e of 3,730,000 lbm/hr per steam generator. Each steam generator also has 5 safe:y valves with a total capacity of 3,917,000 lba/hr per steen generator. The set points for these valves range from 1064-1117 lb/in2 An atmospheric relief valve is also g 'provided on each steam generator with a capacity of 890,000 lbm/hr per steam generator at 1085 lb/in2, g IDCOR.3 3.1-4 ..s* - o w. ,.e e- .-m .n, w m-s. eo - .e,~e.- w- ~~~e.sm===*"

  • e=

- ~ -

e,. C, e * ' MEN::77.AM(L'T157737W.M Ei1T3 ~ ' e;S w ~~ g ,.,s* n nu,Am s. w - B 'A ~ ' y n===mm p.. ll g,=i - - - q, p m At m.s m I ,1~ 4 is li a ia re_ m2 . a m m W b 7 b,. u it. 3 s iEMATEXR {( i k b'&?'V,,. k ygg s EN D I'j y j J k j! 'L! I .n N [ ll lii.. k3 i .,u,.. svhs v. l ,::: j_.4cr.. r '. ?= ig1: hs _. l k g -emm V

i.

NE

9. ;j_

FAXWAT - y %"2TC R!,L m:lllcuxT:::%..cM: ' i .ne t w..!

!GURE 3.12 STEAM GENERATOR CUTAWAY

3.1.5 Reseter coelant ?_ es ~he reactor coolant pu=ps are identical single-speed centrifugal uni:s is vert cal pith ~ i driven by three phase induction motors. "he shaftpqg <, the motor mcunted above :he pumps. A flyt6eb:::rP:he'shaf ' abova ihe motor provides additional inertia to extendg\\\\ D.Qb05# ~ '\\f =n w as:down. ~he inlet is at the bottom of the pump; discharge is on the side. The reactor q ,... &. l%:.stfW; coolant pumps impar: - a total heae input of$2 Kit..to'sFchadynactor wg#gmagg coolant system. f.- 3.1.6 P essuri=er The pressurizer is a ver:ical, cylindrical vessel wi:h hemispherical top and bot:cm heads tha: is connected to the reaccer coolan: sys:am on ene of the hot legs of a reactor coolan: loop. Electrical heaters are installed through the pressurizer bottom head while the spray no::le, relief, and safety valve connections are located in the pressuri=er upper head.

  • he spray system condenses steam to prevent the pressurizer pressure frem reaching the se: point of the power operated relief valves during a step reduction in power level of ten percent of load.

The pressuri=er is equipped with 2 power-operated relief valves which limit system pressure and thus prevent actuation of the fixed high pressure reactor trip. The capacity of each of these valves is 203,600 lbm/hr a: 2350 lb/in2 The relief valves are operated g automatically and can be opened by remote manual control to initiate 1 once-through cooling in degraded events. Operation of these valves also limits the undesirable opening of the 3 spring-loaded safety IDCOR.3 3.1-6 g.

c, E valves. Remotely cperated block valves are provided to isolate the Power-operated relief valves if excessive leakage occurs. Ee's'afety ~ valves each have a capacity of 420,000gbm/h ai 2435 lb/in.:gr ;; ~ e a w-to - '"he pressurizer relief tank is a hori=o'neal, cylindrical vessel with. 5 ...e.6 '~' elliptical ends. Steam from the pressurizer. safety anderelief valves

u......~;,..~"

is discharged into the presssurizer relie* tank through a sparger pipe under the water level. This ~ condenses and cools the steam by mixing it with water that is near containment ambient temperature. Two 18 inch diameter rupture disks are provided n the tank for overpressure protection. The disks fail at a pressure of 104.7 lb/in2d and discharge into the lower compartment of the containment. 3.1.7 Containment Descriotion '"he primary containment uses the ice condenser pressure suppression i - design. The containment, which has a net free volume of about 1,192,000 cubic feet, is divided into three major subvolumes, .. including a 289,000 cubic foot lower compartment enclosing the reactor and reactor coolant system, a 158,000 cubic foot ice condenser I compartment enclosing the energy-absorbing ice bed in which steam is condensed, and a 651,000 cubic foot upper compartment which accommodates the air displaced from the other volumes during postulated loss-of-coolant and steam line break accidents. Figures 3.1-3 through 3.1-6 show typical cross sections. The primary containment vessel is a free-standing, welded steel structure consisting of a vertical cylinder, a hemispherical dome, and a concrete basemat with steel membrane. It has a design pressure of IDCOR.3 -3.1-7 i I n n. ...=*e er r ~w, ..n--+ +. - .-.m ._p.mw.,,. _ -, ~ _. , -.,.., ~ _,. _. _ _,. _. _. _ _, _, - _, _ _ _ _ _ _.. _ _. _ s

12 lb/in2, ;;COR Task 10.1 (Ref erence 3.1) reviewed the ultimate g pressure capacity of the Sequoyah containment shell and esti=ated a' failure pressure greats; than 50 lb/in g. This v'alue was used in these analyses. Design basis leakage is 0.25 percent per day at 12 lb/in2 The shield building is a mediu:n-leakage concrete structure g enclosing the containment vessel and is designed to provide the collectien, mixing, holdup, and controlled release of containment vessel fission product leakage following an accident. The annular region between the primary containment and the shield building has a free air space of 375,000 cubic feet. The ice condenser, Figure 3.1-7, is the primary pressure suppression component. During normal plant operation, the ice bed (approximately 2.1 x 106 lba of ice) is maintained at about 15 degrees Fahrenheit by a redundant refrigeration system. Refrigeration ducts and insulation on the ice condenser walls serve to mimimize heat losses from the ice. The insulation within the ice condenser is suf ficient to prevent the ice frem melting for a minimum period of seven days following a complete loss of the refrigeration syster.. Inlet and outlet doors are provided at the bottom and top of the ice condenser compartment. In the event of a loss-of-coolant accident (LOCA), the lower inlet doors will open due to the pressure rise in the lower compartment caused by the release of the reactor coolant to the lower compartment. The differential pressure will then cause air, entrained water, and steam to flow from the lower compartment into the ice condenser. An operating deck separates the upper and lower compartments and ensures that steam and air flow resulting from a LOCA accident is directed through the ice condenser to the upper IDCOR.3 3.1-8 .;+ ~.

i', l .7* '* py g.

n..

,,...i t I C g g uy',gn,i:,3sg 'u'# U \\ - f J'a J " ' I p c-e.eI ;r f,$ *1 'l ., s:

Q.n ;.fiff.J.\\.,

pl31-W,.#.: l / (CONTAlle'.ENT SPRAY HEA:ERS .i;te N.. y a.. <- gre.8# ~- ,I 175 TON CRANE 1 l p,.h. & f >i -EL 796'7.5' P b6 I Ch l t i V -N2 i L ",]g;{ q [ UNIT F I EL775.6% G i Sifd; (( i i i v. } !w % '%[b> ' N. $ S .. s{ 5. l GENERATOR % Ic! BA5 KITS - j, i /, e m. ,a c_ XWly O W !n: ~ l 4 ~l rREACTOR + fgh j COCLANT PUMP I sRA:t EL 7C5.03 i g,g,5,o' g _P. i I ( 1 ~N'" ' 'O. - \\ l l ~\\ g, -"*n. u,,,.,-.2 n -

  • ~

l ( i.*. A::L'MU,ATOR"#,Al3,Yl -. ;. i i; .c MQht 11 COMPARTMENT t.' 'a 3.~ ..., %......,r ~ numusi - 000LER b h- 'A ,679.7 M t l RCA: tor l

D
  • f: *?.

f': mt t !.S ~"~l

  • l sC: m !NMENT EL E51.6p EMERGENCY SUMP

.;. ? :t';* s.,g. f ji?" FIGURE 3.13 CONTAINMENT CRCSS SEC lON

  • E s

3.1 9 ~ w .g --,4 ^e v+*

. = u.u. :- s 'L.wR 3FUY HEA0ER,.-4

  • y

^ ./ ,. ~ ' ~ ~ A g..; g,.:.' ' AC0hTAlhPINT s7 UY HEA !A j '"=*.,. '4.. ?: ?,, V4- ^ ,..r.. ... ~ ~ POLAR CMN! I g 171 TON *.ADACITY t 4 U.PDE.R PLINUM

  • t. -***

C*O'INO 7j ] COOLIN3 q p UNI;' l TOP CF ICI I UNIT W. g. I SIO. EL 783'.0" # j l l L 1 3 d i..- -l sn m s stuT:a B ic: c:Norssta--7;T c. ji, n:.:w. ( l.g [ 7sl'#"C" r s parssux::ta h EL 733.63 { d i m o s ! _.== _.',, ' O ;, c.....,)/().I. s: sir g Ls s.i.75 ^. k mcox nssa g;;-] N_y. ic_ 'I, ': rI ! E ~ w 4 i i '.-I -/ ETL r' 1 c u et et 7:s.o.

c. M

!N. i@a.V Tr1^ .I/ (rgsy:suixw A L;.... J T,.___. .r in .i rt. f;. sc..TAza - a c r. a a = .it=mer ara =a j 43, i HL, ,' 'l ,\\ ..^ .s.

.?

O 's.'s \\ataton:octwT .pzssvar:rx t

uts.m RILIEF TANK ggg pyyp 1

+t- .,\\

  • y, TYPICAL IN00RE FLUX MONITDA TUSI FIGURE 3.14 CONTAINMENT CROSS SECTION un-m c:

'~~ 3.1 10

g;;. , N!. ._./ '~ AUXILIAllY BLDG Pi~ . s t.: .D*W' I i s s a ? . F;P. n 3 '~ r J~WJ. OTIl ) n T .}fE e j,' AIR RETURN j gg f] EOUlPMENI IIATCil sj FAN \\ PEllSONNEL N [ g LOCK h Allt flETullN FAtl ~ 'Y~a fJ / g= 9 -- fl IIECOMBINEll y {- H ilECOMDir4 Ell 7 N CilANE WALL f S i till f f, _.! *g -- M h T i s 'I' 4 [ \\ C() J I AlfdMENT C / VESSE L n / ~ in ICE 1100 / - SillE t D [; - - - Ji UUILDING o h, )' _,- _-,\\ s. O l l \\ c 2 I l -t 's % f8 EL 778 69 I { .g i ilEACIOR { l t -,,u.. g v i l in d' n s.* 7 f. '. ;n -rp s y' ~l \\ \\ \\ lu _,, a

  • i- <

l )l - (4) COOllflG UNIIS 1 l l;, u (4) STEAM / ,j Q GENEllATolls-i l, ~~~ I ' '. / Q {2, s,,, /,,4 l -(t) flCS PUMP ilEMovAg. .e ilATCll[S ~ Z / . w - p; m ,1 J . ' -'ks':E DED F i PflESSulll2 Ell '(

  • 3

[ ,.,f/ noit: urni I as snown.orn,2 oiroslie

  • N' IIAfdp 4

i j ay, O 3_ C 3' {. T. ; c. m q C 't p g

i. ',

s r s a t a [ {- e t 'l t l L s s O c i t y O Or 1 S c ~ M4 C I !I I 4 t .eiu[l #i. h;i! 'A

1. 'r{;I

~ f lAni "h ,k a f t 1 ,.'l

5 r

xl A j l f j* aC (N'$} Ig F. J ) t-r t i Ou to Cg ~ 4) to l t c - _ { l A I 4f O 1 4( C 3 O,W[ /' r O 'g ]" s ] / f'( l fK I EJ ~ I A R y' / lt I s f i F t / i l E \\ Se g r. sI 9 3 sI S F tt 5 l t \\ e l ~ l rI \\,- };7 'e Al %N f '3 g y 8f $ e8 ' i 1 i t f l l D 1i A 1 S f 1 n >~ ~f.w. t 8 7 S - ~ '; N C L A g = [( a_ h A 4 E / ".L E I-S s g j? y }' i* \\ / p y NN j y Q. I d. / s, q! '8 \\ g> Q' k E .u:() / / / ej 2 /. %1 ) l 8 l 1 J\\ E rs 2l I. i r t l e s N ef % O

  • ,{'8 O'.

l wo r r E WGl S lo. t u = t 04 f 5 s u f t u fOe E t l f $n 5 EG 0AI f t Ct ~ V4 1l A i Sr Ir Ar ll l [CL P A i. t l A O t r 3

o. 8 d

Mi s I A _ [~ Ai i E t lL l C S. E 1 ,8, ri.i 1 sa n I M l( e I i I O r CA t ) a 4 S '!) l* E - 1C lO Al cA fl Mf S f I l I l i f l tE I Pi nll A ~ MtU Ml l O AE M H CG a 4 Et A [ lt l t I i E l Et SG I A S WO W OO li a C t l D L t A E ) M E 4 F 1 z gZg. 9OI$ $,O~O2 ",a d 8 a I-T it*- g.YG j) M-t t n j';. ,i!

~ N / se F. rf FV ' i pc g O, y @_.igi,c;JJ*~ u g.! "f" g t e ra,% / \\; w r,' -C2TAsot2CihEE.L (*uset M r. r:y .>.g...- ..... - ~ y. + wnu.- -. '~~. + :-).

  • $ e[

OUo r,* bEIM M

. (

@ g-2 ff.7 't -{ z_ !b?'h l l 5h

  1. , e. p 5m:m m 5g2,.

..f.1 N ~?:TM.;.: I.e k f ? sY e " v*~ ~,..,',. k$ 9e-k l L i ! m <,.......u a < [ b. s g ly~-M q.-. .e :. e I i fz .',.) ' *.,1 l*'

.s/

{ i 1 g l 3 .I,. f y:- Q. ~. .? i i TW. b-83 ,.$[.'/ N.,nl i 5)' k Y ) G '7 l - LmraDELTTODOE3 .g[ ) d l j ITEAX EDEETDI i:.ij4 ,a., . a, m usts i FIGURE 3.17 ICE CONDENSER CUTAWAY d!'h 3.1-13 qi ,p 4 . ~,. -

- E. ~, compartmen: ra:her than through uncone'rolle'd bypass pa:hs tThs'. resulting pressure rise, due principally \\\\ ?. \\}}

p. lo'-the increased air = ass in the ice condensar at the star: of an acciden: will cause the doors a:
he :op of the ice condenser to open and allew the air to flow from the ice condenser to the upper ce=partment. Steam will be condenaud as it contacts the ice contaired in the baskets in the ice condenser compar: men: and therefore does not appear in the upper compir: ment until the ice is melted. Virtually complete steam condensation is assured because of the ice mass and gec=etrical arrangement of the ice columns. It is anticipated that subs tantial fission product retection will occur in the ice condenser.

A hydrogen igniter system consisting of electrically operated heaters is used in the reactor building contai=nen: to control hydrogen accumula:ics following severe accidents. A total of 68 igniters are currently used in the upper, lower, dead-ended ecmpart=ents and ice condenser upper plenum for this function (64 were conservatively assumed in this analysis based on an earlier plant configura: ion). l Design basis accident hydrogen concentration is controlled by two ~ safety grade permanen hydrogen recombiners. Each recombiner processes 100 scfm of containment atmosphere. The recembiners are l ) located in the upper compartment. The reactor cavity, illustrated in Figure 3.1-8, is divided into a region directly below the reactor vessel and a region between the vessel and the instrument tunnel. The former region is approximately 15 feet in diameter and 20 fee: high. The latter region is 35 fee: in i IDCOR.3 3.1-14 Mwmi*=e.=w==+*aw =g, .m ,y

s s M-r g @ "g. Uo s; -.i q\\ h. (;:hi\\n[i' '.,n 'j p d .g.p. 3 1 lf. if/ s, ,ya \\..Q. \\1 J * + .nbaw s e 2 -w% 7 s .,;r.# :- _;.....;..,Z.'. ~

w. sues @i:s,y.bOWyl$"*

f- .v ...+.. sex.. 9, J T'* 1 t WW.:4 .: y, f$.4# .. *.i..., ' I *I 's t N. i, 'i 1-l 7et'EIS WNC. \\ a.=zss sur:M .\\ N.,,,. .s -\\ [7:e w n :.. 1

c. sein.

\\ .) \\ I \\s'\\\\ ~ J i N. \\ j ; ' y N.... -.... \\ l \\ l ;, j s N'.j 'l - g' ij l ,t I .. 9 .} / \\i; / / : '. Ml(g g ~ /i s I \\.h a m.) \\'k' .i ; \\ l," N. l / w. mea: cavasc.. A g - a c.us.c '\\g \\ !

; q mm er 3

7 s, ('- t l .*l 1 i j t g g \\ /! h i s' c. i j,,, . 4c. u. i.,- ., y i ..,_,...- i g. 1 !

i..

.. =. : A . en;i cm-: F t cac mc e n / it \\ o r,;51 < rm ~. / a c.satas i I i m / ann-s, / I ) i ...~. 1 i ..r. s .m ..s. s t' a i ,;i;m

lGURE 3.18 REACTOR CAVITY CUTAWAY

.i s 3.1-13 --~~e-*-w- - - - * = ~., - - - - - - ~ - - - ~. l

i I l length and 23 feet in width. This unique design has i-portan: \\ %. c '; consequences in the behavior of Sequoyah for degraded,-ace'idents int 3,qc,. y9 tha: the ge==e:ric cenfigura ica precludes;-ecriu= dispe-sal' into the a* lower compar:=en:. ?crtuna:ely, :he cavi:y has a relatively large floor area for debris cooling. The in-core instru=entatics passes g...a through an instrument tunnel starting at %;hi',, seal'iable and in:ersecting the rectangular region at an angle of apkoximately 60 degrees and 5 feet above the cavity floor. A personnel access hatch is located at the upper end of the instrument tunnel opening into the lower compar:sen:. ~here are two pathways for water to spill over into :he cavity frem the lower comoar:sent. The first pathway is :hrough :he reactor vessel nocele penetrations in the reactor shield wall. The second pathway is for water to accumula:e above the personnel access hatch flooding the cavity via the instrument tunnel. a 3.1.8 Containment Heat Removal System The energy released to the containment following an accident is absorbed by the ice condenser. However, af ter the ice bed has melted, mass and energy will continue to be released to the containment. The containment spray systems are designed to maintain the containment pressure, in the long term, below the containment design pressure, and eventually reduce the containment pressure to about atmospheric pressure. The containment spray for the Sequoyah Nuclear Plant is provided by two redundant spray trains, each designed to provide the cooling capacity required to main:ain the peak pressure at less than design pressure for the full spectrum of design basis events. Each of the redundant IDCOR.3 3.1-16 , 3 S 4 .ww- -,,- r-, --u-e -.v --r-,

containment ~ spray train pumps delivers 4750 galices per =inute to the containment. Additionally, 2000 gallons per minute may be diver'ted frem -t~., - one residual heat emoval pump and heat enchanger *hrough. a RER' spray u header. The containment spray pump is stafted by a contai= ment pressure at 2.81 lb/in2, - and containment spray starts at about 30 signal set g seconds af ter a large loss-of-coolant acebdent,(,, Co'ntainment - spray from .a the residual heat removal pump may be manually initia'ced. The contai= ment is equipped with a redundant air return fan system. Each of the two air return fan systems uses a 40,000 cubic feet per minute fan to force air from the upper compartment back to the lower compartment. The air return fans are started by the containment pressure signal, but the fan startup is delayed for 10 minutes to ' provide increased backpressure during the large LOCA core reflood. 3.1.9 Emergenev Core Cooline Svstem ~he emergency core cooling system (ECCS) is designed to provide core cooling as 'vell as additional shutdown capability for accidents that result in significant loss of water inventory from the reactor coolant system. The design basis is to limit clad damage due to excessive temperatures and cladding metal-water reactions. Important systems are diagrammed in Figure 3.1-9. The emergency core cooling systems consist of both passive and active systems. The upper head injection and low pressure accumulator tanks are passive systems that are actuated when the reactor coolant IDCOR.3 3.1-17 ~- ,.~..-

y _u t = s *8 s- -1: u-- D .nn. b t l 1 l -m R '\\ S 'uc'a.M: ',G O. o s

  • I *I W i u. C pijg W

d. d" )f g 'g t 0-1 f t I h N ....i... ?.. - y N d &.q~,g(:c.d;sh'M-I, I f = ' ~ - n

== l l i i ng 552 i i99 .( / -i 5 3 f ( e< si, l =s _u z pe:c l =i r x 2 _, C, " t

  • =,

1 ~ -.= s = i 3:i ,. S, J l.., 5 ,1. 1 pi-- s u. F*"}' Ef. uI I e)1 ~ e i = = g: { s a. xa .......... h..... 2 5.. ........ 1.._..........{.. ux...i.w. e. s..x.t.e w i w ... e

animc2 xm
a n

o m i 8 I E 5 3 .E%. 1t = = u. a v E 1 i 4 li ens y., t j, L } l .a.. o. :. _L.- - - I_ _- i I u g 'u'. _ _, _ ' ._ :_:_i_. a _'_:_: Ei p 5 ,7 e, se w. , o o, EE ) s< = v s ~ ~ e r a s e r:: r

  • mJ

.= 6 5 I /w a $s = = 2.)9 5 as N ) C gM 2 ) ,d. ns

)

FIGURE 3.19 EMERGENCY CORE COOLING SYSTEM FLOW DIAGRAM 3.1-18 wm- --y.- e- ---y7 _---c--, ,-9wwav-y y------9-vr-N-- .-----*-*-Y w w-

~. 1 pressure falls below 1255 lb/in2a and 413 lb/in,,,,,p.eggy,1, 2 7 The active components of the emergency core cooling system are hig!1-9 J -e ff head (charging), medium (safety injection), and low pre's's'dre.(residual' ,. 'l, ..,. j s ' ' :' heat removal) pumps that are actuated by a saIek EjAer,iori signal. )L -- Following a postulated accident, the passive and active injection systems may be called to operate, and af ter the water inventory'.iri the ' , j w.v ~ 4 3 refueling water storage tank (RWST) has beenai~pleted; the long-term recirculation mode will be activated. The emergency core cooling system incorporates two subsystems which serve other functions. The residual heat removal system provides for decay heat removal during reactor shutdown. At other times the residual heat removal system is aligned for emergency core cooling operation.

  • he centrifugal charging pumps are utilized during normal operation for maintaining the required volume of primary fluid in the reactor coolant system. Given an emergency core cooling system actuation signal, the system is aligned to emergency core cooling operation and the chemical and volume control system function is isolated.

i The upper head injection system consists of a borated water-filled tank connected to a nitrogen tank that is pressurized. When the reactor system pressure falls below 1255 lb/in2, water will be a injected into the top of the reactor vessel. This system provides potential for top down quenching and upper plenum cooling during degraded core events. Nominally,1839 cubic feet of 12007 water is-available for injection into the upper head region using this passive system. IDCOR.3 3.1-19 .- se i .*m- .-a ., > = - %op.e ,ye=w .e m eme -+ e,e,

Each of the four low pressure accu =ala:Or tanks contains approxi=ately 1000 cubic feet of borated water pressurized wi:h ni:rogen gas to l-approxi=a:ely 415 lb/in2 a When the reacior coolan: sys:em pressure falls below the: in :he accumulater tanks, ya er -is' forced into :he four cold legs. The' high pressure injection mode consists of the opera: ion of two high head centrifugal pumps, raced for 150 gym at _2300 lb/in2, which g provide high pressure injec:ica of borie acid s'elution into :he i reae:or coolan: system, upon actuation by a safety injection signal. l Also par: ef the high pressure injee: ion mode are two safe:7 injec: ion 1100 lb/in2, which take sue:ien fren pumps, rated fer 425 gp= a: s

he refueli:2 va:er s:orage tank.

Low pressure injection consists of two residual heat removal pumps l-which take suction from the refueling water storage tank. The pump performance is 4500 gpm at 125 lb/in2 Switchover from the g injec:Lon to recirculation phase is accomplished manually with au:ematic backup, i.e., automa:ic switching of residual heat removal pump suction from the refueling water storage tank to the containment sump a: a level 40,000 gallons below the low level set points in the RWST. (Approximately 350,000 gal are injected from the RWST.) 3.1.10 Auxiliarv Feedwater Svstem The auxiliary feedwater system is designed to supply unheated water to the steam generators for reactor coolant system sensible and decay heat l i I IDCOR.3 3.1-20 .s l t e What - we .e- -Naes>*** = * *ge e

u., _ _ removal. This need would occur when the normal feedwater system is not available.- Therefore, the auxiliary feedwater system w-111 be utiliced in::the event of during certain periods of normal startue and shutao,ygp nd ~5 is eat f l malfunction such as loss of offsite pow 'j ~u O u

  • g, i accidents.

c.1.a.gfemagp14. c,a. -ryki~.

.... ;;#5 The auxiliary feedwater system contain[('2yawGTEartven pumps and one turbine-driven pump. Each motor-driven pump has a capacity of 440 gc11ons per minute, at 2900 feet head, which is sufficient for safe cooldown. ne motor-driven pumps are connected to ser:rste emergency power buses. The turbine-driven pump has a capacity of 880 gallons per minute at 2600 feet head.

1 Steam supply to the auxiliary feedwater turbine is taken from one of two main steam lines at a point upstream of the main steam isolation valves. Separate remote operated isolation valves are.provided for these connections. ( Normally, the auxiliary feedwater pumps take succion from two condensate storage tanks. Each tank has a capacity of 397,700 gallons of which 190,000 gallons is reserved for the auxiliary feedwater system by means of a standpipe in the tank. The condensate storage tanks are not designed to seismic Category 1 requirementst however, the essential raw cooling water system provides an alternate source of water. All three auxiliary feedwater pumps will start r automatically in the event of a safety injection signal, loss of offsite power, tripping of both main feedwater pusps, or tripping of one IDCOR.3 3.1-21 .- s

  • hsinse+
  • Wegeme m 4my.

_ w q> we+ . 4_m 4 ._,__._-,.,,___...__._.___,-eein_. _..... ,___._..____._....._-,_,._m.,.,_...___,J__,,,,_..__.

main feedwater pump if plan: load is grea:er :han 80 per:en:. In addi: ion, che me::: driven pu=p s arts au:cuatically in the even: of a two-out-of-three low-low water level siinal in a.y Mea = generator. '"h e .., > - g turbine-driven pump also starts automaticaljlye3.n <he event of a.ao-ou:- of-three low-low water level signal in any steam generator. Auxiliary feedwater flow will be adjusted by remote-operated flow con:rol valves. ...e . :u ~ ,..;;s.., The valves' associated with the curbine-driven pump are served by both electric and con:rol air subsys: ems. ne :urbine-driven pu=p receives control power from a third direct curren: electrical channel

hat is distinct from the channel serving :he electric pumps. Except for the common supply line from the condensate :anks, the :wo reactor units have separate auxiliar r feedwater systems.

IDCOR.3 3.1-22 ,=g.3i=4 T g.4.A4-e e

3.2 MAAP Code and Inout Model Descriotion Evaluations of degraded core accidents must include assessments of steam formacien, clad oxidation (hydrogen formation), hydrogen ecmbustiona,,' - r i g - y.t - E tphd ll core-concrete attack, fission product behavior et c previously discussed plant systems mest be pro, r1 modeled in conjunction with their respective trip logic to accurately portray -:a pp, m .,, a.v. ;> accident progression. ghk;b The basic purpose of MAAP is to provide a general accident analysis program to treat these phenomena and plant systems over a spectrum of accident sequences. The sequences have been identified in the probabilistic risk assess =ents that have been carried out for those plants which IDCOR has designated as Reference Plants. PWR assessments have generally found that the accident initiators can be divided into three categories: (1) a large break LOCA, (2) a small break LOCA, and (3) transients. These accident initiators have been considered in terms of the availability of various emergency safeguard systems, both within the primary system and the containment, and the effectiveness of these safeguard systems in maintaining primary system inventory, core cooling, and containment integrity. The occurrence of the accident initiators combined with the failure of protective systems has a small probability. Given the potential for uncovering and overheating the core, containment response is governed by the ability for water to be centinually supplied to the debris, the ability to achieve a coolable debris configuration, the availability of containment hest removal, and the ability of the centainment to either withstand hydrogen accumulation and combustion or prevent substantial hydrogen accumulation by measures such as controlled burning. 1 IDCOR.3 3.2-1 W shiii ie w e -e m-w hye si regie 4b eN +hw me-- e e.m p e m m g im W m eua=* O

  • Wb$,r M dD'&4 s

i

"'he MAAF code is ceganized en the basis of physical regions of the plan:. The regien subroutines asse=ble the differential.equatith's' -. m-W governing conserva:icn of internal energf an'd -bss for theiy,reepytive au-r- ,, w u part of the medel (on the order of 1000 Oualions). "'his is done by calling the phenomena subroutines which calculate the rates of the varicus g..c::iwM C.. physical processes. Specific phenomenit[pa% hay,. bh N hr[pIiate anal k . r.. w.. simplifying assumptions are used when plant behavior is. insensitive to the details for the models chosen. Examples include detailed examination of URI top down quenching, corium debris cooling, corium en:rainment in the instru:nen: tunnai, and hydrogen burning.- Si=plified treat =en: is used for in-vessel melt reloca: ion and core support place failure. A key feature of :he code is :he use of an array consisting of " event codes" to characterize the instantaneous state of the system and to control problem execution. Event codes are logical flags aose values are either 1 (true) or 0 (false). These flags nave three roles. Some event code values are calculated by the code (e.g., Ras a burn occurred in the lower compart=en:?). Others are user-selected to define ~the accident sequence by specifying external events (e.g., Is AC power available?). The third category of event codes is used to define operator actions (e.g., Is the high pressure injection manual actuation switch in the "on" position?) which can modify hard-wired system logic. All of these event codes are defined in the central subroutine EVE!CS, and the set of their values provides a concise characterization of the state of the reactor plant which can be ased 'by the region subroutin~ s e during the transient analysis. Key ac.. dent event codes are su:mnarized in each transient output; this list is useful when examining the problem solution. IDCOR.3 3.2-2 w + w ww,...-.g., .....e., u.-, g 7-,?- pr_ -e-c

8 Finally, it should be noted that these analyses have utilized simplified, fast-running codes to represent the core heatup behavier following core In this evaluation, the code assume @s_,'t7. atuche %,e', m @. r0 ~ ot*- core can be.. \\a; uncovery. QWUdd eM. divided into into seven radial regiens each wi{_. }en axial nodes. Within - each node, the fuel, clad, s tructure, and coolant are assumed to be at the. .o. ~...

; 9'
:.u...p z,. -

same temperature and the oxidation behavior Mllytef [+he..'s$f-di Eats ~. ' p diffusion race laws which are well documented ~ in the literature. Comparison of this simplified PWR heatup model to the more detailed model being developed by EPRI/NSAC demonstrates reasonable agreement for both the a=eunt and. rate of hydrogen production as well as core heacup during and af ter substantial oxidation. The MAAP plant model is divided into two parts: a primary system model and a containment model. Representative input describing plant geometry and systems in the MAAP code is detailed in Appendix A. The following subsections provide informatien on modeling assumptions used in compiling certain inputs 'that require additional explanation. 3.2.1 Primary Svstem Nodalization The PWR primary coolant system is divided into nine nodes as shown in Figure 3.2-1. Nodes exist for the core region, downcomer, broken loop cold leg, broken loop hot leg, unbroken loop cold leg, unbroken loop hot leg, pressurizer, and both the broken and unbroken loop steam generatrr secondary sides. This primary system nodalization permits a reasonab.'y detailed accounting of the water which is available for cooling the core and for reacting with the Zirealoy cladding. In addition, this scheme allows for the user to track hydrogen concentrations through the primary system and thereby calculate hydrogen IDCOR.3 3.2-3 v..eeo e. aeee-oom = .,~--~w , es e -

  • +-sw

v{I .I ? .l, l .r j , ' i.. )* q\\ .I- ,.,,, 5 7Ut E?. f. .p cr s g .i. :., i-. s C' l ; M y.* g _ k \\ O O E E L L i D l a t 'l L E n 0 O M sna > 8-G O 1 G-l 1 l l E i i K K W O-O O O l l i l _l- _l l l l il!' iI \\ \\ M M u U l l i l E E E L L l l l .! ) l .i O

. (

l l l C_ l E E W 'I O I U ? l q l L r E f I / l l i l l S-- 1: I l O-O l E E. E A L L l l U I l' T D l I l O L l IIlli s ),i1I ( O A / i / s l l C l s3Jl s E l i rlIII s e I1ggg K E (i O K O l l l / l l l l l _ I i l W i t U \\ . ) cre(~ f8 aI T,ep i 8 I n s o:'li'5 uD" s ,.,?,. F o'., =l t.oI" d i' l-

release races to the containment. Further, a separate, user-selected core nedalizacien is used for the Sequoyah reference _analy, sis. Top'd'wn o cr; quenching is examined for the upper head injecti,on system flow and-botpom up quenching is examined for cold leg ECCS fio\\ y.., w: Reactor coolant pump 4 coastdown is simulated in all cases where the pumps are stopped either by operator action or loss of power. The majority of the primary system data comes from the Sequoyah Final Safety Analysis Report (FSAR) (Reference 3.2) including initial condition pressures, temperatures, flow rates, snthalpies, and = asses. Additional information describing system pressure set points, rated relief-valve flow rates, control logic, ECCS parameters is also taken from the FSAR. Reactor coolant pump coastdown data is taken from FSAR analyses. Geometrical input data such as flow areas are obtained from vendor drawings and/or documents. Volumes representing components such as the cold leg, hot le g, pump " bowl", and steam generator inlet and outlet plena are based on a single loop. The pressurizer heater power input is based on the summation of the backup heater power and proportional heater power above that required to supplement ambient losses. The axial and radial power peaking" factors are computed for the representative core L l consisting of 10 axial regions and 7 radial regiens by collapsing a more r ( detailed FSAR core power distribution map. Pump curves for the ECCS t including the charging, safety injection, and residual heat removal pumps are derived based on ECCS Performance Analysis. I I l IDCOR.3 3.2-5 1 . ~...

I l ,3.2.2. Con =ainment Nodali=ation j "'he nedalizatica 'of :he ice c:ndenser ::::ainmen: is shewn in Figure 1 3.2-2. As illus::cted, the cen:ai==en: is divided in::.eegiens f.:r-I g -c f '., 7 M ice cendenser and #:sydp Fule:'umn m uua ph I

he upper ccmpar: ment, compartment, quench tank, dead-ended comptreden:, and reactor cavi:y..

I Input data ' including ini:ial conditions, free volumes, exposed surface and walls, and flow. areas between._e$cb455'2far;e s. . areas of equipment 'q ;1-Pe*~" based on FSAR information. This information is listed in Appendix A. The walls of the ice condenser and the upper plenum are assumed to be insulated. Only the containment floor and/or vall areas that are co= mon and uninsulatad are =odalad as regions for energy exchan;s :hrough heat transfer. For the upper compartment this heat sink area consists of the ice condenser deck, upper compartment ficor, and the s: cam generator and pressurizer dog houses. In addition, energy can be transferred by conduccica and/or convection through the standing steel shell, containment annulus region, and shield building (concrete) wall to the environment. A natural convection heat transfer coef ficient is calcula:ed for hea: transfer in the containment annulus. A constan: heac transfer coefficient and heat sink temperature are specified a: the shield building outside wall. l L i i IDCOR.3 3.2-6 4 e e-p , ape me<,6 6 %a -mm..4 ww4 e e =% ^

- < : O e C

  • ..m 'l O

a; ', g - \\;g . 7 ev,= p g a'u '.; '( hw, 6 i:{*

[" { I 7..

$:m w j~; w- ~' 1

. 4.,,,,;~,
.:..' *'

l l M u.*.e t,a . s.. N,,, set v s p. d d i P Scustwats v h ' rsa 'w V**I s ',. s. d n 0 i qt: s i 4n: ,. a... = **.. .=r = s=osta ....u..:.. e O / aug M lj v1 4 ( Panf anta r ] f "!.omest e vu q sa. Low e n 6 g / N ) MesAmeggAJe kF / la. i c' _, ... 4a, l l' I '7 a sa t we a r, ~ .us.. s... h #J 0 / l ?-

:r -

g, .s $T878u V,4 si g Y ' /////////////, ,l/,//f /

Y.

,g v,;: - t ';'////////W/,

55b, UFFER COMSARTMENT atT1 s'

0 9 0ftam s ~ *a;,f,; - m.atsmessa A N N U'.'A R t.eeeewe BCE CONOENSEA COWPARTWENT e.eae gsage,gg,,ggj UPPER PLENUM "='* se .r...... LCE e,c w g R i coMe:N R eeuri, wsNr s . ~....... CUfMCM TANG .......n ) CAVITY t ..e o ue.e s..e.e e PRESSURt*1R peggggy SYSTEM s ..n. ae J BRJKENLtt S*IAW GENERA?cR UNB2CKIN LIO(3) lat AW c NERitencas i i 19tI* N 5.,,I Tigure 3.2-2 Ice Cencanser Cen:21:sen: Noda*.1:ac h n 3.2-7 =_... _.....

o The su=ps modeled in the contain=ent system include :he lower compar: ment, ice condenser, 'and reae:or cavity. The upper co= par:=en: is nor= ally assu=ed unable :o re: sin cny appreciable c=ount of water -and ~ d therefore drains directly :o the lower compartment.' E~he ice condenser sump is assumed to retain a small amoun: of water before also draini g :o the lower comparrment. The lower compartment sump will retain the most water and is used as a reservoir for both ECCS and con =aioment spray recirculation. Excess water in this sump spills into the reactor cavity. The air return fans are assumed to have a delay :ime cf 10 minu:es following a containmen: isolation signal. Con:ainment sprays are activa:ed "on" when the containmen: pressure exceeds 17.5 lb/in a. The af fective height of the spray header in the upper compartmen: is based on an area-weighted averaging technique. The total dead-ended compartment volume is the summation of all the smaller dead-ended subcompartments. The representative flow area between the lower compartment and the dead-ended compartment is the summation of the subcompar: ment flow areas. The total flow area between the lower cespartnen and the ice condenser is the summation of the lower ice condenser door areas. The containmen: failure pressure (50 lb/in2 ) was determined in IDCOR Task 10.1 3 (Reference 3.1). t l 3.2.3 Safety Svstems Modeled in MAAP l The safety systems considered in the Sequoyah analysis include the charging pumps, saf ety injection pumps, low pressure injection pumps, l passive cold leg injection and UHI accumulators, auxiliary feedwater, pressurizer safety valves, pressurizer p0R7s, steam generator safety valves, s team generator PORVs, ice condenser, and centainment sprays. IDCOR.3 3.2-8

These are shown in Figure 1.2-3 along with other systems i:nportant to the accident progression. All of these systems can be enabled or disabled at the discretion of the user. The MAAP User's Manual (Reference 3.3) gives a complete description of the application and use of the MAAP and also compares the physical models with pertinent experiments. nc % rF 31 ~ O IvUw / .,..u- , g;; :..: " ' ' ~ ' IDC01.3 3.2-9 ~* .. - :. :r. : . - :~ "- 2

-= s.. a i ~.. ~~ a. o. ,.,9,... a... -. + i i i a ! it!:i,.: li I .i sa n. 1 t$ sh1I . -U 'j. '. I le is = s i l !l ~. 115 = ,= y::ggat e d qjp ..l.lI.!iillilisil 5 \\ 'E i fi. 3-

as sss:His g

g lj [,: y .I $INIII@'II!

! g j C t;j I
[

r x

n C

i 0 + ? I c I = ~ = N 8=

  • 5 I

N M != ( m .= ; l tu = 0

f. *,/.

I* vi l zw e + -l ? ~ ,,,~ 2 gv / J ,a M h 3 O 2 i :-T::. 4r w g, h:.: < LO. 9 Q ~ 'R. .a M, v E U * :. iI 3 3 o w w ~:: "n rs m ~ m e -

4..; #

.g .O N 4 37 m) E i.:=8-i. ~ . :: D - u E i.$. ~ U 4 w M I f i n s.':. ~.).: - w. U 4 lig 7. d,, J. E T r. N '..: / l. g c

i 43 1

I gl w .u -s 2 : _,I ::: g I: g .i :: n.

  • b e
n a
O 2!

~ -&l 5

  • i l.

l g I. I I J 3 2-10

. /, 4.0 Seeuences Analyzed C nfa~fTea,. o -t" ~ p:: dOig'.ro Considerations of the dominant accident sampi :klrgW\\\\Wt}fsk 3.2,ICCd. 66 % potential core damage as given in the draf t regert. (4.1), resulted in six small loss-of-coolant-accidents and two transient initiators, comprising 94.4 percent of the 1,ikely.ycore dan g.;ini;tiacors V A ~ 6,$A These sequences were developed by reviewing-the Sequoyah RSSMAP study with some regrouping of sequences. The AD accident sequence was added to determine the plant response to a 10 inch diameter LOCA. Translation of these sequences into the Sequoyah reference plant input model include the following assumptions: 1. All loss-of-coolant-accident (LOCA) sequences incorporate manual reactor coolant pump trip via operator action subsequent to reactor scram. 2. Credit is taken for the full complement of emergency safeguards for accident sequences where they are available unless otherwise specified. Table 4.0-1 illustrates the status of both primary and containment systems for each accident sequence used in the analysis. The sequences analyzed aret SD - Small LOCA with loss of ECCS injection, 1. 2 2. SH - Small LOCA with loss of ECCS recirculation, S HF - Small LOCA with loss of ECCS and containment sprays in 3. 2 the recirculation mode, 4. TML3' - Loss of all AC power and auxiliary feedwater, 5. AD - Large LOCA with loss of ECCS injection, and 23HL - Transient 'with loss of auxiliary feedwater and loss of 6. T charging pumps. The use of MAAP for predicting primary system and containment response imposes ene significant modeling constraint on the user in that MAAP does not, of itself, contain datalled models of fission product physical IDCOR.4 4.0-1 ..:~.

m ~2 1e '.."-1 OOINA,,^OV R'y R i A..,i q 9 - 3 i.- Lq .s. .. s i i u v,s i. -~

  • I

/ENT .e W .e - ") ' e '.:.".: :

  • f ' '...e ::., ' g, i N

[ i. RC: CCASTDCWN l X l X j '4 -- f ~ X l X jX l L.:PER HEAD X X X X X X I NJ ECTI O N ._s. . m_ e-CHARGi N G X 4.X '~' Pugss SAFETY I NJ X X PU435 RHR PUaDS l X l l X l l l l CCLD LEG X X X X X X ACCUdu ATCRS.

.. a--

.. ~- C' - "- l l ~ j i l .n ECCS hT XCHNG l l l l l l VAIN FEEDWATER l l l l l l l AUX FEECWATER l X l X lX l l lX .s CONTAlNMENT SYSTEMS STATUS ETMNT l 52H l520 l 52HF l TMLS' l T23.NL l AD AI R RETURN. X X X X X FANS SPRAY X X __] X l l X lX SPRAY RECIR C l X X l X lX SPRAY hT. XCHNG l X l X l l l*X lX l I GNIT CRS l X l X lX l l X lX l l l l l l l 4 'y k.0-2

behavior. This is not a ::ajor limitation for the noble gases, which remain as gases in the MAAP modeling, or for the very low vola,tility, materials. A f :e-T ? which have the form of either liquids or solitis.Te latter group yields W b'%fjddOU0"

  • 6 the major fraction of decay heat and thus govern / tN overall containment-response. However, the volatile fission products which can be vaporized, _

and condensed at various times and regions AMnkjed5EN?N YE W modeled in MAAP in terms of these transport ~pr'ciasses. 'This can be a o limitation on the realism with which the transport processes and consequent fission product heating can be modeled if these materials are highly mobile during the accident progression. For purposes of this evaluation, two bounding phenomenological cases can be examined with MAAP to establish the reasonable ranges of containment response subsequent to vessel failure. The first case assumes that all of the volatile fission products are released from the primary system at vessel failure and that these remain in the gas space contributing decay heat directly to the containment atmosphere. This case allows the essium, iodine and tellurium to be released into the containment gas space at a rata dictated by the flow between the primary system and containment. In this evaluation, the fission products are removed in the ice condenser through the user-assigned DF. While this ignores, the very real aerosol formation and depletion mechanisms depicted in the RETAIN code it does result in the shortest time to containment failure. When this case is coupled with RETAIN, significant early depletion of volatile fission products in the containment atmosphere is predicted. l IDCOR.4-4.0-3 + ,,-==q .-w+

s. (.. r I' The second case ~ assumes tha: all of :he vola:ile fissien produ:: are held wi:hin the primary system through vessel failure and that subsequen: i I retentien is virtually :otally effective. Hea: release fre= :hese fissien i products is not ::ansferred frc: :he pri=ary system :o :he cen:ain=ent l atmosphere by MAA?. This overescima:es :he time to con:ainmen: failure r l l somewha:, but permits a maximum late release of volatile fission products, l as a vapor or fine aerosol at the time of containment failure. t \\ l- .,~ .,m.,.,. _y-9 i

... 4 :. % '

... + .. ~. . ". ;,_;f. y - -.., .s, j;, s ' ~,, i 1 i l ~ t I i i r l IDCOR.4 4.0-4 m

i r* ; p : ~~

  • l 4.1 Secuence No. 1-50 2

4.1.1 Accident Secuence Descrietion sed consists of a small LCCA initiator Ed.tha g., a _t.fai. lure of..a;,.. subsequen ~- the emergency core cooling system (ECC$t-in' the injection mode. The ECCS continues to be unavailable in the recirculation mode. Containment safeguards systems (ice condenser, sprays, air return fans, and ignitors) are available throughout the accident. 4.1.2 Reactor Coolant System Response Upon initiation of a 0.0218 ft2 cold leg break, the reactor is scrassed, followed by reactor pump cossedown and auxiliary feedwater startup at five seconds. Figures C.1-1 through C.1-5 illustrate the variables of interest. Immediately following break initiation, the primary systes pressure decreases to approximately 1255 lb/in2,, Ag this time (approximately 0.08 hrs) the upper head injection (URI) rupture disk fails and relatively cool vecer injection is initiated. The race of inventory loss out of the break is partially offset by the injection of CEI water. The primary system depressurization continues as decay heat is being transferred to the stess generators and lost through the break. This gradual depressurization continues until 0.90 hours at which time the core uncovers. A slight pressure increase is indicated as the reactor vessel gas temperature increases and superheated staan is liberated from the core. As the water level in the core continues to drop, the cladding temperature begins to increase. Approximately 0.26 hours after core uncovery fuel nodes approach 19400F and the metal-water reaction initiates hydrogen generation. The generation rate is somewhat constant between 1.1 and 1.6 hours. Between 1.6 and 2.4 hours the hydrogen generation race is IDCOR.4 4.1-1

O O esser.:ially zero due := the slu= ping of :he c re esterial issul:ing in plugging of :he channels in the high tempers:cre reglen of :he core. qs, .L; t i. approxi=ately 1.6 hours, t' e primary sys:e= pressure drops rapidly as A: a the remaining vuter fres :he CH is injected (CHI depte: ion at 1.83 v

  • ..,, =.

hours). However, the injected unter does =st jeneirate and ecol the upper core regions since mere :han 5 per:ent of the core is =ol:en and the influx of us:er is bypassed :o the lower plenam. This addition of water pr:vides cooling of the icwer core regions. However, the increased s:as=ing ra:e daring :his be::c=-up quenching resul:s in a rapid pel=ary sys:em pressure inersase :o a peak of approximataly 1000 lb/in2. A: a appr xima:ely 2.3 hours, :he primary system pressure has dropped belew the 415 lb/in2a set poin: for the cold les accumula: ors and cool vater injection begins. At the :Lse of injection ini:iation the reac:or vessel water level is abou: 9 feet, which indicates the bo:: m of the active core is uncovered. The effect of :his " bottom to top " reflood is to initially quench the lower nodes of the core. However, this quenching is not maintained and :he heat-up of the injected water supplies steam to the cladding-water reactien and hydrogen production is restarted at appreximately 2.4 hours. As core nodes reach the melting temperature (first node reached 5144o7 at 1.61 hours) the mass of molten core collecting on the core support increases until about 137,000 lba (50 percent of the original core mass) have accumulated at 3.02 hours. Ac this time, the lower core support place fails and the molten core material falls into the lower plenum of the reactor vessel. Approximately one minute later (3.03 hours), :he molten core material falls ene of the penetrations in the bottem of the vessel and the =el: is IDCCR.4 4.1-2

t \\ 1 I 5 l discharged through the hole into the reactor cavity. Following the i l. molton' core, the remaining hydrogen, steam, and water is di.scharged into , ' '.T ~. J the cavity along with the remaining accumylatorTw,a,, terr 7he cors nodes remaining in the vessel continue hean\\gp~(-(~3. Qigd#" W d!ifg ud@hNr: ally. As each node l a-reaches 51440F it then falls into the cavity. .The corium disch I rate af ter vessel failure decreases.with.theif,inal; shing the egypc. e melting camperature at 8.0 hours. T$U$ h regen production from in-l vessel Zircaloy saidation is 435 lbs. The average rate is 0.09 lb/ses and the reaction is equivalent to a total s' ora average clad oxidation i of :: percent. ? 4.1.3 Containment Resoonse - Innediate Release of volatile fission Products The following section presents the results for the first case discussed in Section 4.0 in some detail since this represents the most conservative containment response. The second case is not presented since containment failure is not predicted for this sequence. l Immediacaly following the accident initiation, the lower compartment pressurises as RCS inventory is discharged. At 63 seconds the j i containment spray pressure set point is reached. The containment sprays l f take suction from the refueling water storage tank (RWST) until recirculation realignment occurs at 0.4 hours. At 3.03 hours the vessel L fails causing a pressure spike to about 20 lb/in2a with an associated I lower compartment temperature increase to 2350F. The available air return fans, ice, and containment sprays decrease this temperature to l approximately 1608F. Since the ice has not been depleted at this time, the temperature response in the upper compartment does not exhibit a i similar characteristic. Pressure suppression is effective as j f anticipated. As the ice continues to melt and RCS inventory is lost from IDCOR.4 4.1-3 i-e I l

r...... ::-~::

~ ~ 7 7 ~ : i J

he break, the wa:er level in the lower compar:sen: ex:eeds the necessary curb heigh: required for spilling vs:e in:e :he cavi:y 4: app :xima:ely 0.8 hours. Therefore, by the :ime ::ac::: vessel failurs occurs, :he cavity is flooded. This flooded condi: ion limits cere-conche:e abla:Len

.~ I to the " jet" at:ack resulting in a 0.17 ': pene:ra:Lon' dap:h. )-The ~~ a, g w s. flooded cavi:y resul:s in immediate quenching of the corium. The remaining ice cass at time of v ss,el.failu're 1 approx!=ately 9.0x105 lbs (about 57 percen: =al:ed). A: 5.0 hours all o8 :he ice has cel:ed and con:aln= ant pressurica:!cn be; ins. Following i:e depletion, :he ice condenser and ice condenser upper plenum

e=peratures !==edia:aly increase :o approximately the lower cocpartmen: temperature. The contain=en: sprays continue :o remove heat fren the containment atmosphere as indicated by the depressed upper cecpartment temperature with the con:inued molten corium discharge from the vessel and the decay heat fres quenched debris generating steam.

This heat removal rate catches the decay heat at approxima:ely 7.3 hours when the =4xi=um cen:alnment pressure reaches 20.4 lb/ int. Af terward, e the contain=ent spray heat removal este exceeds that of decay hea: rnd the contain=ent pressure continues to decrease, thus precluding containment failure. IDCOR.4 4.1-4

s_ c - g... Te le L.1-1 F1MAAP S2D 0 .s SEC l HR l EVENT DESCRI P Ti O N m:S-n 3 o jl lCCCEl 0.0 0.00 REACTCR SC.ht ggEu 12 0.0 0.00 AUX FEECWAHR CN ~ 15A 0.0 0.00 MSIV CLCSED ).c.t56 PS BREAK FAILEgjWyl'jiq~ $$$ .I02 0.0 0.00 3REAK IF ANY INgCCLQ LEC- - 209 0.0 0.00 0.0 0.00 H.:l F CRCED CFF ~ ~~ 216 0.0 0.00 L?l FCRCIO CFF 217 0. 0.' O.00 ' CHARGi N G.:LMPS FCRCEO CFF 222 60.5 .02 N%IN CCCLANT PLMPS CFF 4 63.4 .02 CCNTMT SPRAYS CN 102 1A60.S . e-1 REC R C SYS i ed i N CPERAT1CN 1Si 1460.3 41 REC R C SWITC-i: N%N CN 220 1466.1 41 C-f PWPS IN SLF NPSH 153 1466.1 41 HPl P WPS I N SUFF NFSH 155 3223.0 .90 CCRE UNCCVERED A6 5797.9 1.61 SURN IN PROGRESS IN I /C LEPER PLENLM 1 41 6357.1 1.77 SURN IN.:RCGRESS IN UP:ER OST 102 64M. 6

. 78 SURN IN PRCGRESS IN ANNULAR CST 122

,.q 6575.5 1.83 UHI ACCLM EMPTY 190 5672.7 2.41 SURN IN PRCGRESS IN LCNER CMPT 75 9331.6 2.59 NO SURN IN LC#ER OST 75 10497.7 2.92 NO SURN 1N UPPER OST 102 10515.7 2.92 SURN IN PROGRESS IN UP.:ER OST 102 10598.5 2.94 NC SURN IN UPPER CST 102 10695.2 2.97 NO SURN IN I /C UPPER PLENW 14,1 10768.8 2.99 SLRN IN PRCGRESS IN UPPER CAPT 102 108A1.A 3.01 NO SLRN IN UPPER OST 102 108AA.6 3.01 SURN IN PRCGRESS IN UPPER CMPT 102 10856.8 3.02 SUP.:CRT PLATE FAIL ED 2 10863.6 3.02 NO SURN IN UPPER C#T 102 10868.7 3.02 SURN IN PRCGRESS IN UPPER CMPT 102 10525.8 3.02 NO SLRN IN UPPER CST 102 10917.4 3.03 RV FAI L ED 2 10917.5 3.03 SURN IN PRCGRESS IN UPPER CST 102 10920.8 3.c3 SURN IN PROGRESS IN I /C UPPER PLENLM 1 41 10922.8 3.c3 NC SLRN IN ANNULAR C#T 122 J ' y,1 3 * ' '~

w ..s ,..,3 q ._ A AA, m _,. o"'. 4 y(~pS Tll. v 2I i va _,, '\\. ,.ii. l

e. r. e.-

l w:

nj.-.yi.,.r..e. u.=. l.: p. r, n., e. t +.2-

..g . s. n.,.. ;, .w . C 9 c..i.:

  • 2.

e ve.N, 1N e r.L ens e s. e...- - N. -x u.. .-j w ,_4

  • 0c,c,o.c, c.Os-C - M*s *s u n~
u..v.. ~:.~-t., :. s : :. >

i ~ ~~~ ~~ -~ c 11001.6 2.06 5 URN I N .:RCGRESS !N LCNER Csi:7.. 75 % #*"'j xd-I C"*/r.:.Im ry.3.- tic's.a ,aa NO " URN I N ~* l- ~ - ,m i.< 12196.3 3.39 NO 5 URN IN U::ERID1:T 102 12303.5 3.42 EURN IN PRCGRESS IN C::ER CS'-

02 12341.0 3.43' NO " URN I N UP
ER CST 102 12455.5 3.47 NO SURN IN ANNULAR CST 122 12511.5 3.45 5 URN IN ORCGP.ESS IN ANNULAR CST 122 12531.5 3.48 NO EURN IN ANNULAR OST 122 1 n n. o *i, s

' so.

.un.N l N.= =.r C_~..=.v

s N.~ 9iyL,-. n-e..r.:,- 1 nn. .i

  • **) $. 2 4.2

..g,Q Q f'\\ 31 'C..Q f kf I '/* l *C.3 ? ~.N Cl.?1 %' % ) \\f L Y =wi esi e/ I. s two a=1 1255c.2 3.49 NO SURN IN ANNULAR OST 122 -. h, h. .,, c-a.. .,,.9 1 n, CR..:.a-- -c i., ,., ir- =i .42 swa c .4. n-m ev 12565.1 3.49 5 URN IN PROGRESS IN I/C UP:ER :LENLM i ci 12722.0 3.53 NO SURN IN I/C U.::ER.:LENLM 1 41 12505.9 3.56 NO EURN IN ANNULAR OST 122

  • < =., E n 0 A. ".

.=UR N I N.:R O'e~:.....e _t ..N m' N N L'.,' R C /.: T

  • 07 i

15591.5 4.33 NO EURN IN ANNULAR CST 122 16i70.9 A.49 EURN 1N.:RCGRESS IN ANNULAR CST 122 16185.1 A.50 NO EURN IN ANNULAR OST 122 16265.0 4.52 EURN IN.:ROGRESS ! N ANNULAR CST 122 16279.2 A 52 NO SURN IN ANNL1 AR OST 122l 16467.0 A.57 5 URN IN FRCGRESS IN ANNLLAR CS-

  • 22 16A93.5 4.55 NO EURN IN ANNULAR OST 122 16573.6 A.60 EURN IN PRCGRESS IN ANNULAR CST 122 16604.5 4.61 NO SURN IN ANNLLAR OST 122 1502a.3 5.01 I CE DE:L i:D 132 i8029.3 5.01 SURN !N PROGRESS IN ANNULAR CM:7 122 1*059.3 5.02 NO SURN IN ANNULAR OST 122

~. ? w .s u., -c ~..

4.2 Seeuence No. 2 - S;g 't,, c. ~4..-:

  1. ~

A.2.1 Accident Secuence Descrietion p.,, e j ,i,y 4 4 ', 6

~ -

04'.ch{suh'sequEnc failure of ~ S H censists of a small T.CCA initiate: 2 y-the emergency core cooling systen in the recirculation mode. Emergency core cooling in *.he injection. mode is success *a1..and 'the containment safeguards systems (ice coEde[sseY,p.%i LW 5d5O sprays, air return , fans, and ignitorsi are available throughout the accident. .4.2.2 Reactor Coolant Svstas Reseense Upon initiation of a 0.0218 ft2 cold. leg break, the reactor is scrammed, 'followed by reactor pump coastdown, and auxiliary feedwater startup at five seconds. Figures C.2-1 through C.2-5 illustrate the variables of interest. Immediately fo11owing break initiation, the pr mary system pressure decreases to approximately 1100 lb/in2,, During this depressurication period (0.0-0.04 hours) high pressure injection started at 0.C3 hours with URI injection initiation at 1255 lb/in2. This introduction of cool water into the reactor vessel a results in initially cooling the primary system water. An equilibrium point between the rate of inventory loss out of the break, heat tran.rfar to the steam generator, and injection rate is reached about 0.04 hours. At this point, the URI injection stops as the primary syst.em pressure increases due to the net increase in the inventory supplied by the ICCS pumps. The primary system water mass and level continue to increase imeil 0.37 hours when the recirculation switchover point is reached. This increase in primary system inventory and cooling results in the secondary side temperature and 2 pressure dropping to approximately 5150y a 790 lb/in,, respec.tively at the time of recirculation switchover. Since the primary systata ' pressure is continually decreasing af ter unsuccessful IDCOR.4 4.2-1 J '~

c o recirculatica svi:chover, :he "EI cen:inues :s inject pas: 0.37 hours. "'his continued injectica cools the pri=ary and sec=ndary side un:i1 a

ini=u= pressure of about 3C0 lb/in2a is sached in Tae.,pr.i=a y ? ~I

+ \\, e..,., n.3 p. system. At this point, the primary side prekure heginsy:3,ine-$se.f; tt yb-- w due to secondary side heating. "he pri=ary sfde pressure increase resul:s in termination of UH! injection. Since heat removal through

.....a..u.~jp.sd ?r# 8~" '"

u.,...~ boi.:.h.u f;nt. /* TeTondary M the break is less than the decay heat, pressuri=e to the secondary side relief valve se: point of appreni=a:ely 1100 lb/in2 'fi:h no more va:er available for a injectien, reacter coolan: inventory centinues to decrease as does the va:er level vi:hin :he pri=ary sys:es. The pri= arf system pressure remains somewhat cons:an: un:i1 about 1.45 hours. A :his ti=e, the reae:or vessel.; ace: level falls below :he top of :he core and superheated steam begins to exit the core. As the water level in the core continues :o decrease, the cladding :emperature increases. Approximately 0.30 hours after core uncovery, the first fuel nodes approach 19400F and the cladding metal-water reae: ion ini:iates significan: hydrogen generation. The increas'.*: void. in the primary system coupled with the increased flow out of :he break causes a depressurization at a rela:ively constant rate until 1.8 hours. At this time, the pressure has decreased enough for UHI injeccion initiation. This introduction 'of cool water condenses some of the steam in the reactor vessel thus effecting a rapid decrease in upper plenum camperature. URI injection continues until depletion occurs at 2.17 ' hours, af ter which 'gs injected water is quickly heated to reactor vessel conditions. During this period (1.S-2.2 hours), the UHI injection is insufficient to quench the fuel resulting in continued hydrogen IDCOR.4 4.2-2 ges e qg -e-,

e. pga.m. op

, wie w 4%. %-gwumim sei+a a-e w%,

  • asi--**

=%>

e, i, l 2 production. Immediately f ollowing UHI depletion, regions of the core reach melting temperature with a corresponding rapid increase in upper plenum temperature. ?. a e \\@y ' p.g..:, + ~i # " 6 - Atapproximately2.4 hours,theprimarY#3ystem pressure has decreased to the cold leg accumulator set point (415 lb/in2 ) and bottom-to-a . ~ ~ ~ top reflood is initiated. This resultszin.providing additional water for steam production and further oxidation of the cladding as indicated by the continued hydrogen production. Continued accumulator discharge causes the vessel water level and mass to increase as the pressure decreases to approximately 250 lb/in2a As the core continues to heat up, the first node reaches the melting temperature of 5144o? at 2.07 hours. Increased heating and node melting results in the molten core collecting on the core support plate until about 137,000 pounds have accumulated at 3.04 hours. At this time, the lower core support plate fails and the molten core material falls into the lower plenum of the reactor vessel. Within one minute, the molten core material fails one of the penetrations in the bottom head of the vessel and the molten core material is discharged through the hole into the reactor cavity. Following the moiten core, the remaining hydrogen, steam, and water is ~ discharged into the cavity along with the remaining accumulator water. The core nodes remaining in the vessel continue heating adiabatically with each node draining into the reactor cavity when it reaches 51440y. The corium discharge rate af ter vessel failure decreases, with the final core node reaching _the melting temperature at 8.0 hours. A total hydrogen mass of 420 lbs is generated w.th an average hydrogen productico rate of 0.10 lb/sec. This corresponds to an overall Zircaloy clad oxidation of 21 percent. IDCOR.4 4.2-3 -vr-

4.2.3 centsi=en: Res onse - I=adiate Release.of "ola:ile ?ission ?redue:s ~r'? The following section presents :he results Ep)..r %. D irs:acase irg e=e., f,1 \\.\\ Q gua G- ? e. detail since this case represen:s :he =est conserva:ive cen:ai=en: response. The second case is act cresen:ed since contain=ent failure is E@A+F-~M.. ;.:IE # ~ W "," ". w, +

$,5i- -

.. :. u. no: predicted f : this sequence. W. t Immediately f olleving the a iden initiation, the lower ce=partmen: pressuri es as RCS inventory is discharged. A: 64 seconds, the pressure se: poin: for de contai =en: spray is reached. The centai=en sprays

ake sue:icn fr = the RWST until :he recir:ulatica alig=en: ec urs a:

0.37 hours. A: :his poin: de spr:ys recir:ulate water f :m the conta#-- m: su=o. A: 3.05 hours h.en :he vessel fails :he lower compar: men: pressure increases to 20 lb/in2a and the lever :c=part=en: temperature reaches a peak of 21507. However, the air return fans, containmen: sprays, and available ice reduce this temperature :o appecximately 160 F. The water level in the lower comoartment exceeds the necessary curb heigh: required for spilling water into the cavity a: -appr:xi=ately 0.8 hours. "*here f ore, by the :ime the reac::: vessel failure occurs, the cavity is flooded. This flooded condi: ion limi:s - core-concrete ablation to the jet attack caly resulting in a 0.18 f: penetra:ica depth. The flooded cavi:7 results in the '=nedia:e quenching of the corium. ~ The ice remaining at the time of vessel failure is approximately 7.0x105 lbs. A: A.6 hours all the ice has been melted and the containment pressure rapidly increases due to loss of the passive ice heat sink. The containment sprays continue to remove heat frem the contain=ent atmosphere, but lag the input decay heat energy until 6.6 hours, at which time the peak containment pressure of 20.6 lb/in2a IDCOR.4 4.2-4 A g..w- %,.ges.e eemym= -m,we.w=e%+,=- - +, -~-o-+

is reached. Afterward, the containment spray heat removal rate c ,-c' exceeds that of decay heat and the containment prMsn=e coTeinues to fau,((ure.'@v,..y.e".$h .\\ @ t Y '\\- \\ \\ decrease, thus precluding contain=ent ~

i...

Referring to Table 4.2-1, the hydrogen burning due to intentional _ b ~i...~. v < ignition in the various compartments is -i'ndicated. '~Eic..-.h compartment experiencing a burn is presented along with the associated burn duration time (see Figure 4.2-1). Hydrogen burning is initiated in the ice condenser upper plenum at 2.24 hours. - After about 4.5 minutes of localized burning in the ice condenser upper plenum, results in a flannable mixture in the upper compartment and burning is initiated around the igniters in this compartment at 2.32 hours. Due to the forced circulation, the hydrogen concentration reaches flammable conditions in the dead-ended compartments approximately one minute l'ater and approximately ene minute later the lower compartment experiences a burn -of about 130 seconds duration. All of the above mentioned compartments (except lower compartment) experience continuous burning with another bur-initation in the lower compartment at 2.51 hours. All compartments experience continuous burning until about 2.6 hours at which time the f l invessel hydrogen generation rate has decreased to near zero resulting in l I the lower compar nent' burn cessation. However, the other compartments continue to experience incomplete combustion around the igniters at a decreasing efficiency as the hydrogen is depleted. l-Immediately following reactor vessel failure at 3.05 hours, the lower r j~ compartment hydrogen concentration increases to flammable limits and l l_ localized burning is initiated at 3.07 hours. Approximately 7.8 minutes i i later, the lower compartment burning ceases. The other compartments IDCOR.4 4.2-5 I l 1 .-,. 7 _

l . A. ', (upper, lower,; ice condenser upper plenu=) cen:inue burning un:i1 app :ni=a:ely 3.48 hcurs, a: -t.ich ti=e :he upper ::=part=en: burn s: ops. The i:e. condense upper plenus burning ceases 214 secends la:er. I ocali:ed inec=plete ::=bustion has ceased at 3.36 hours, with only sporadic burning.occuring in the deadended ce=part=ent un:i1 ice deple: ion a: 4.63 hours.. e O D ,. ~ I g , e .. ~ T E IDCOR.4 4.2-6 ~.. _.. -+-e..e -,4--+, e ia

4 tl.

  • -; Ii

- i! l' I 'e.,., - l' i.e 'loI, l WI i, { cr 4 1 N J ) ( c D }L b6 T - T 1 3,'i, N i oti(to n)r. t F O 2 a- )i ' 2 _UOOd_ ~ UtU 3I f t 7l-i i t t l. ~ )! a c <t ( i O.O O.OO tlI'.OIOt nO(l{7 i - ) t a o l-i lf (3X .tltO3(=l-lt OZ O.O O.OO i ill ,t .(.

  • ii T

QVt ['.g: ".:sMk%il.>dAyj8-i i h M p. k Io 2}t. > U._OilO O.O O OO i /. ] ni I .j y4.M1 l 7 l L. NO0 (ub cg)(3 (, itt t l;Y i O.O O.OO nte i 8 Jt9 1 ) iO NOo l O.O O.OO tn lt .a ( _ ai tiI < d . n i 3 F O. )G Oe UT(*Mb. z O L)a,)v OZ e. i (.. ( )n i t i. tt s D,.O ON Nr< z UOOJ.t.zL-t.q(,) M OL.i j n Dl.j ON UOZ _ - UIt <>in OZ .OP ( - - iLr(- I t - N0.O Ol)' xn. - OZ o 1 t I tl i .P0tl8D.P Pt xt-O.i.a n w ) . l f I. i1 PP1l40.l is 0T(*tb:7O I)$ni Ot1 P Pi n at i I

  • l.

. (. w tlUtU n>1 - z Onttit(~ - OZ n-PWD.P Pt t i 1 l ) 1 . ) OtUIO Oii PvtD 1 ( t .- PN0.F Pt xL-t t.i a i w 8 - - i ) . ) l l') O. :- Mi i I ) 1 1s J.n. OtUi( Pi 8 t - (N0 - - s >(Z OZ NPO e U IE l-Ur- <td t ePNo.P Pt t n i w tl I ) i . 1 ePNo.P Pt UT(< tO. z O .1 ntlOt OLt NPN t i 1 tI t tl lw ) - ) ) - Psi [.O FI OT .H n ziJtl Z(LnI enP (i I N n i.a )1 1 ' . ) t. (i , H4 x(- t32(iL n z I.n 3s..t Zn.iI -1'll.O Fi lsv L n s )1 . ) t 4o U U r j J Z U D >'i a t tdtla tI fOtP.4 i , 4c n i wI ) t UUEi U dtla 4o (l ft oOt1w 0. )G e.4-t t i = t leltto Jo n 0P.o r.4N UU(t JZU t ie a i a tl 8l , 0O t(U 'N o N.t J;E. (UU$7 i l t 5 w w 8 LrOo(tlIn _2 _NO 3tn.,li tZ3 i ,ae i. (t tDI nJIZ. 7 r nOIN.P N.N4 t. - l-t i t s n)CZ _ ~z ttOo(iittdno.23(atfLtit O 4'l-EON Il ) i

i. l ii t

i.n N.lN iP )' t l )I , 0N t Il iJtZ. z ((OU[(tttloo. 2 .r< % Z.. (* t O JQ U. (1 N.P4 (

  • i

)J nt LE 8 ) ) l t fi tit 1f Iu )os. O N.Pt' nJiZ. z tnOo(Clno _2 JO%dt sn Gtie 1u i ) t bo 1 UwOO.i N.YN zO uJ(tZ.z _iD=ti U2(,1 - <t f dt s I ti eJiZ. z L 'Oo(tlln. 2. U=ti O4-wn tti an nt (n 8 ev OONG.0 N.n-i / J j n ) bn i I 1l zO IJiz z _aO=Ii O e nP.. N.GP t dr - )I )1 ) L (. _ dO P I i i I il n>L.Ot--(n il I_ OOPW.O P.O4 a 4 1( s t1) n ) .g t i 1* F .OOOtw.4 P.Oo t> 1 (__ J to u ) nn 1 ti .Oo..O P.Ot o]tZ ._Z LrOo(tiao _2 _13>iI d4l. wn t t. ( (f tlt ( w dE l ) < (g aia_dtfl - I'O U) .Otawl.o P.O)G (UUJ2)eJ( Ot 3(<l-dt t -l ( lI i 1 tt iI ZO i- (Z 2 _aU=ttr r U2f - wo . o )' w-.o F.NO tt t l>r l a ) ON Ne *Q. )G P.l) ZO )HJ(tZ.z Jn.itttlr Us,tl aP t l i i i 1 itOO'(_ti n n 2 J(Ln.aE d4l-EON tii (t# iJ{tZ ~7 eNPoP.P P.4P t tr n l l i i 1 1 1 J.d~ i: ) 5 1 i,; i. f, 'i l -f

f

e + i'.*. ',. ;1 ,'ai, t.,'e ( (N g<,l<:O v( ' d, - ':@h~. f .ls p~~ - rde f , cg, l ~ ) ~ p h.3- ~ VlU t 'g t fNt-[- n l. O Z. -I o !l ot.r2 sit i i. i i i(t / ,t l l. Il1 Nn)tU.l )' 7O l i s t 5 t ( H. 1t .)tz.a J.nstt OI'.nr 1I i_ ON n PsPIN.P F.4n . 4i) i tDnZ. Z .H(tOJrlIIPttVV _Z "nii ZO i. (Z. Z DtI.t E :o 'p i. :!<.e..d P. - . Ol8' i i t -i. ot 1 ) l 0,oN.O F. J)u ~ iIiI ._ OP 1 n)t s I 8 n ) I t t Po o.i P.J)n ZO tDtZ Z (*ZZ.J(<n o%l s i NM 4 s i l ) l NuNP.J P.ja n3nZ. Z L t OU'(t lll Z R sn i (t ttt s" tis di l ON i i/ .i o t ) 1 ) NONO.P N. l,o nJ(tZ _ Z .n(OU'(tt))tVV _Z iZ;.<ti d9. i. ._ (0 a i s n I - i E ]r 18 i t ~ 0 n j*. o P.jn t i ZO l)tZ. Z 3L.t a.r oini_ oN t ( . (ilf i 8 l l - 0oe. N P.no t i Z O s Dt Z _ Z 4ZZ. m. ,t t; o % l-NP l e i < s )J 8 ) I Nu,O.0 N.n. I f 3iZ _ Z

n. t OU't t VV _Z t

5Z. 4t d o. i pN i r t i tlII ).J t n 8 i a - Nuissj.N P.oN ZO n3tZ _Z CZZ..<( 0 % l-T t i I tO ).I(r t l ss N o iW.. P.nN _Z i Za. i d 9, i. _ t'0 e tDnZ. Z tVV l .l n O >U(t ( ~ n I i i !(t lII s8 r0rtln.) N.nn i 0 i i ZO iDtZ.Z NU Dn(L83t -"..iZ _)7 I n 1i i I1 4 ).- NnOi.s P.oot ZO lDiZ _Z 4ZZ.,.t o%l _. NI t i t t nl ) i t ) J,t;t s' Nn,oO.l P.oo I >t Z _. z n n OU't t V! _ % iza. t ds; t t i I t f NN i i / i n I tlI3 J( NoNO.)(t )'.nn t i i ZO i.(Z.Z (ZZ.,.t o4l t( nJE )J(t s n n si - jr t G 4. o t f i( i a3nZ. Z t K OU'(t lI)tVV . Z 4Z. <n dai_ eN r .)]a; . ) s - 4nnP.l t ,.- o ZO nJfI _ Z e szZ.. n N (g* a l J. g ) ). t. J ii s . j~ ss.U j. t3tZ.Z tEOU'ttVV Z Q2;m t dai. .o i l II i , NN i i rlII lr n frG1)0.) P Z O u D(Z _Z (<ZZJe (<t d "i t I a iN t l l i

  • i t

a .. jsO. o l.e.- taJ(t Z. Z L 'OU'(t (O ttV ._ Z #Z)" Jct o4_ <i . ep r it l)) n tg - l,n o t 4.,.- a ZO lDIZ _ Z (ZZ <t d"i NN t t w i I t t inIN.d j.No . = iJ{tZ Z L E OU'n t tV _ (( Z iZa. < n dai. N0 ? .Jr: r i r n

li) 8 ZO tDtZ. Z 4ZZ3.. I o % l-toditso.e

.PO I e . sp ) n . rt ] . qg ) e s n4(o. N .Po t 3t Z._ Z L E OU'n t VV Z i Za,J(t dai . Np i II i i t j

l))

g ) ) 8 i = 0oP,.d .Ps ZO iDtZ. Z 4ZZ.. < I dSl-r pN n ).,rt j j 8 i I a t ii ( s t - oon.- O f.Po i3tZ. Z H D OU'(t o1ItVV ( _. Z QZa <t dwi (p n I J(t 9g ) - or.tw.o -.PI t ZO rDtZ _Z 4ZZJ..t os"l-gp \\ s I N n I(t _ yg ) eiP t i (( ns)N.o J.P~ nDtZ. Z L E OU't t V V Z iZ..<e)]rr dni_ _ Np i tl)1 m I 1 g t . orlO.N j. )' r a l ZO n. (Z Z 4ZZ_).J(t dol-i <( 3t _ Np g ~ nrnO.r l.Pa e i n 3iZ _. Z L K O).(t t V V _ Z WZa<}r< t d m i. . NN r (I ( a t i 'r l I I )) orO .s l.Pu ZO f. t ( i w i 3 t Z Z 4 z Z_). ( . (t d " l- < ( J _ pN )) n 3 tiU os)o.4 4.Pn (DtZ. Z i L(O OU'(t i V V. t .. Z iZ. J(t i d t i. Np n l)I i )) g ai t s - nsOo.o j.PO ZO nJIZ Z (<ZZ.,<I o % l-i Ng )_1(t t y n s i i . ioa a n,lo.P j.lN n3(Z _. Z .OIOU't tVV _ i i _ Z i Z a. < i d u i. ? )(t NW t U rlII =. s I ton r o,Ie.l d. Nl* Z O i D ( Z _ Z (* /~Z_].J (< t 0 % l-N(1 s nt e oit t3iZ _ Z L . n.so.e j.I'l ( D Os 'I t V V a t i ._.Z nZa <aJ(t dwi Np ut )tln1 g O,a 8 f -lt, l;l!.- 'i!>! r fi -l l r. i

. - - ~ ~ a 3*'; *

  • 7 1
  • * - - =.

.=. F2MAAP S2H CONT. m, i SEC l HR l EVEN" DESCRI:T1CN ! CODE l i6C18.5

  1. . 3-6 NC 5LRN 1N ANNULAR Cn:T l122 161C3.5 4.47 EURN I N :RCGRE55 iN ANNULAR CA:T i22 16159.9 a.49 NO ELRN IN ANNLLAR OST 122 16306.3 a.53 SURN IN RRCGRESS IN ANNULAR CA:7 122 16338.9 4.54 NO SURN IN ANNULAR CA T 122 16532.4 a.59 EURN IN RRCGRESS IN ANNULAR CET f22 16556.6 A.60 NO EURN IN ANNULAR CA:T 122 16597.3 4.61 EURN IN. RCGRESS IN ANNULAR C4:7 122 16609.4 4.61 NO SURN I N ANNULAR CA:T 122 16648.2 4.62 EURN IN.:RCGRESS I N ANNULAR CA:T 122 16660.1 4.63 I CE DE.:L:::D 132 16698.6 4.64 NO EURN ! N ANNLLAR Cvi:7 122 y

a

  • N n

V ,s d w .' e k.2-9 ~2

w 0% "A m.e en.o g I. O e og=.

    • e e *me e

g -g e,= 09 'A n } g, ,, u u t.;;d J u u m' 2_ L',W u ,6. i. i I eP L :1 g M ," oY e ess.a I. r.

n.... m.

m, .....g.- cS;.

  • f.T e arE, -OM.med;* hh===ma g

, ;t <. .T i,-i*fj=**.tM.Y.*E I.i' I. Ml!!!mE I t."* l "v ' l = i. ei Z -- 4 o t. i. w ,I ~. m l '* O g 1 e f amm. i I. .ia Nz [ "2 e). y 1n..- D -m L m.- l. _L CN I. I

i. e.

l I. l. l l. f I y O I. o

taJ, O

~ m.s-2 y ~ a C Oo n Z O l C y n t e =.1 9 O te.m t'h'. W W e e em m.a 6 w=== m W W m k.2-IO ~**=up,em,--e. .+enw.w.,_ g..,g,._o

_s

.{;-{ hat.Lu.; w
q 4.3 Secuence No. 3 - S HF 2

4.3.1 Accident Secuence Descrietion S HF consists of a small LOCA initiator with subsequent failure of 2 the emergency. core cooling system and centain. ment spray system in the recirculation mode. Emergency core cooling and containment sprays are i available during the injection phase only and the containment (- i safeguards systems (ice condenser, air return fans, add igniters) are available throughout the accident. The following sections will present two scenarios for this accident sequence. The first sequence (4.3.2, 4.3.3) postulates that the drains between the upper and lower compartments are either closed or blocked resulting in the spray water accumulating in the refueling pool thus preventing the normal flowback from the upper compartment to the lower compartment sump. The second sequence (4.3.4, 4.3.5) presented postulates an equipment failure preventing the accumulated water in the lower compartment sump from being recirculated back into the upper compartment. 4.3.2 Reactor Coolant Svstem Resuonse t Upon initiation of a 0.0218 ft2 cold leg break, the reactor is serasuned, followed by-rasetor pump coastdown and auxiliary feedwater l - startup at five seconds. Figures C.3-1 through C.3-5 illustrate the l l primary system variables of interest.. Immediately following break initiation, the primary system pressure drops to saturation pressure f followed by the initiation of ICCS injection at 0.03 hours to replace l the mass of primary coolant lost out of the break. The ECCS system-IDCOR.4 4.3-1 [ 2::, - ~ ~. _ _ _ _ _.. _...

O .o supplies water to the RCS be:veen the :i=e of 0.03 and 0.37 hcurs. During this time period, the RC3 pressure rs= sins se=ewha: constan:. W.en the prIEir;,.py.s:e:r(ofssa'Oe dr$ps ne UE: begins to injec: va:e f/ h 1 'p: , q h lj r 1. d 5a YEI'sfs ine~ m below 1255 lb/in2. This addi:ien of cool vi.te' a primary system pressure to a c:inimum of about SCO lb/in23 a 0,33 hours af:er which the reacter coolan pressure. and. te=perature._........ej;:1,.41 tgy{jgg;.i:i3:# = '~~ increases due to the heat transferred fr.ei.n. sEohdarv. side. Continued loss of pri=ary system i:rientory leads to cere uncovery at'1.42 hours accoc:panied by initiation of the cladding me:al-water reaction producing hydrogen a: a signifi:nn: ra:e around 1.f heurs. Tota'. hydrogen predue:ica ia 380 lbs a: an rierage rate of 0.10 lbs/sec. This corresponds ' to an average clad exidatien cf 19 per:ent. A: appecxi=ataly 2.4 hours the primary system pressure decesases below 415 lb/in2a and the cold leg accumulators begin to dump water into the reae:or vessel. The core continues to heat up us:i1 suf ficien: molten fuel accumulates leading to failure of the cere support p1. ate. The =ci:en corium falls into the lower plenu= at approximately 3.02 hours. A: 3.04 heers, the vessel fails and the remaining water, hydrogen, remaining accu =ula:or water, and molten corium is discharged in:o the cavi:7 region. ~ 4.3.3 contaie=ent Reseense - I= mediate Release of volatile ?issien Preducts The second case, presented in se :ica 4.0, is judged :n be more closely representative of the overall con:aimnent and fission product response. Recention of fission produe:s within the primary syste= is predic:ed by CIRC and RETAIN. The predicted hea: transfer from :he pri=ary systa= :o the con:ainment a:mosphere is influenced by the reflee:ive insulation employed on that system. However, the following section presents :he results for the first case since this case represents the mos: IDCOR.4 4.3-2 j.

conservative containment response. The second case differs mainly in the time to containment failure. The resulting fi,ssion producj;. hehavior is .c - F. i.:'% t..,.c [; wg' y __ g, [p e ' " discussed in Section 7. i.,,- immediately f ollowing the accident initiation, the lower compartment

-P e,...

pressurizes as the RCS inventory is' disc;hargedR. At.64 s.. -..:,-econds' the . a: - pressure set point for the containment spray is reache'd. The contairunent spray takes suction from the RWST until recirculation switchover is attempted unsuccessfully occurs at 0.37 hours. At 3.04 hours the vessel fails and the containment pressure increases to 22 lb/in2a and the lower compartment temperature reaches a peak of 26007. The forced circulation of the air return fans and remaining ice reduce the temperature to approximately 160e. At the time of vessel failure, the r water level in the lower compartment is approximately 6.5 feet, which is less than the 10 feet necessary for spillover into the cavity. Although the containment sprays have delivered all the RWST water prior recirculation switchover at 0.37 hours, all of this inventory is trapped in the upper compartment due to the failure to remove upper to lower compartment drain plugs. Therefore, the molten corium is released into a dry cavity. Inunediate concrete ablation occurs due to " jet" attack during the corium blowdown, resulting in an initial penetration depth of 1 0.25 feet. Following reactor vessel failure, the water level in the lower compartment increases due to accumulation from the melted ice but never i reaches the necessary 10-foot spi 11over height. Therefore, once the water discharged during vessel blowdown (cold leg-accumulators and f remaining vessel inventory) is evaporated by decay heat, the corium in l IDCOR.4 4.3-3 I ~ ~ ~~ ,~;~'""~~~ 2.7 T.*::. _ T, * ~.7 s

the rea==:r cavi:7 reheats and ther= ally a::acks :he :: crate base =a: generating concendensible gases.

  • he = ass of ice re=aining at :he ti=e of vessel failure is approxi=stely 7.0x105 lb=.

he air re: urn fans in conjusetien with :he re=aining ice previ.ie con:stkgag.es scrEC' :

1. h m,. t

. y

.,n which ti=e t a'
P 'G u.I d.e 'gs = eked.

suppression until 3.62 hours, a: -heji ~4ith

y... g g no =ethod of re=oving decay heat frc= the centainment, and the con:inued generation of noncondensible gases fr== the core-cencrete attack,.the ?

fatlu re pressure of 65,ubg:,.,,m:s..,.L%.Lh...M.;-i*;.:ii.;:i~ ~;iV : .6 .y.,.. contain=en: ng,.igerdachE a: 18.92 hours. At this ti=e, the contain=ent rapidly depressurizes through the assumed 36-in:h diz=eter contain=ent failure hole. 4.3.4 Resetor Coolan: Svs::= Res :ense (Drains No: 31ocked) Upon ini:iation of a 0.0218 f-2 cold leg break, the reac:or is scra=ned, following by reactor pe=p coas:down and auxiliary feedwater startup at five seconds. Figures C.3-6 through C.3-10 (later) illustrate the primary syste= variables of interest. I==ediately following break, initiatien, the pri=ary syste= pressure drops to satura: ion pressure followed by the initiation of ICCS injectien at 0.03 hours to replace the = ass or pri.mry coolan: lost out of the break. The ICCS system supplies wa:er to the RCS be:veen the time of 0.03 and 0.37 hours. During this ti=e period, :he RCS pressure is approxi=ately :enstant. The UEI begins to inject water ~ when the primary syste= pressure drops belev 1255 lb/in2a This addition of cool water depresses the pr' mary syste= pressure :o a mini =u= of about 800 lb/in2a at 0.55 hours af ter -tich the reactor coolant pressure and te=perature increases due to the hea: ::ansferred from secondary side. Continued loss of pri=ary syste= inven:ory leads to core uncovery a: 1.423 hours accec:panied by ini:ia: ion of the cladding =etal-water reaction producing hydrogen a: a significant rate around 1.6 hours. IDCOR.4 4.3-4 aspe m we epe -m= e,w eewer4m- ~ =,onsu op. e- -s e- .q e

===ne.ew =- =w*

i . t Total hydrogen production is 380 pounds with an average race of 0.10 lbs/sec, which' correspends to an average clad oxidation of 19 percent. At appreximately 2.4 hours the pri=rry system pressure decreases belew 415 lb/in2a and the cold leg accu =alators begin to dump water into the reactor vessel. The core continues to heat up until suf ficient molten J fuel accumulates to failure of the core support place with molten corium flowing into the lower plenum at approximately 3.02 hours. Vessel failure occurs about one minute later and the remaining water, hydrogen, remaining accumulator water, and molten corium_is discharged into the .x.p. reactor cavity region. 3g }y + u w G i 4.3.5 Containment Resoonse (Drains Not Blocked) ",,u : - ,,.,..,v..>.W. s 4.3.5.1 Containment Ressense - Immediate Release of Volatile Fission Products ~ Immediately following the accident initiation, the lower compartment pressurizes as the RCS inventory is discharged. At 64 seconds the pressure setpoint for the containment spray is reached. The containment spray takes suction from the RWST until recircualtion switchover is attempted unsuccessfully at 0.37 hours. At 3.04 hours the vessel fails causing a containment pressure increase to 22 Ib/in2a and the lower compartment temperature to reach a peak of 260cF. The forced circulation of the air return fans and the - remaining ice reduce the temperature to approximately 160oy. Well before the vessel failure, the water level in the lower ecmpartment has equaled the height required for spi 11over into the cavity. Therefore, the molten corium is release into a wet cavity. Immediate concrete ablation occurs due to " jet" attack during the corium blowdown, resulting in an initial penetration depth of 0.25 feet. However, IDCOR.4 4.3-5 .a 1 _p. .,....y .. -.~. ,--y =

after :he debris is quenched, no =:re cenerete a::ack occurs and the centain=en: ; essure re=ains low until the ice =el:s. Subsequently,

he contai =en pressuri:ss due to s:cas fer=a:icn.and fcils in 3

' hours. 4.3.5.2 contai=ent Reseense - Retention of volatile Fission Products in :he ?-imarv Sys:em The basic contain=en: response for :his case is initially the sc:e as for che preceding case. The significant redue: ion in 2:sespheric hea:ing =anifes:s i:self, subsequen: to ice deple:ica, in a si:ver ra:a of con: sin =an: prassuri:acica wi:h the ' pressure rise being due solely to nonvola:ile fissi:n product heat input and noncendensable gas generatien. The ci=e :o con ainment failure is stretched frem abou: S hours in the preceding case to abou: 15 hours in :his case. . ' rQ .1 \\.'. ' O

  • ?., \\

br1e\\\\\\\\h$ 9 g. ......:W...%,. .....9

  • ~. r.:.n.,,

,Lig ~.us-h r t v,. p *,y,. # g~ e .-e 7.: y q g,n e y._.. ':.e.4-7. .y. ~ 72.@ pen IDCOR.4 4.3-6 6

  • v ese e

+=.eu.- r *ee++, w

4.,, g

,4g== c gy w e.igepe up.m e #..

N::le u.3-3 F3MAAP S2HF l SEC l HR l EVENT OESCRI P TI C N lCCOEl 0.0 0.00 REACTCR SCRAM 13 0.0 0.00 AUX FEEDWATER CN 154 0.0 0.00 MS!V CLCSED L !.' 2. h a - 156 0.0 0.00 EREAK I F ANY ! N COLD LEG 202 . S 5REAK FAIL ED 209 0.0 0.00 ~ 11 39.5 .01 CHARG N G PLMPS"CN ~"" 4 61.9 .02 MAI N CCCLANT-yLMPS 'CFN# 64.4 .02 CCNTMT SPRAYS ON 103 125.9 .03 H.1 O N 5 1334.4 .37 HPI OFF 5 1334.4 .37 CHARG N G PLMPS CFF 11 1334.4 .37 CCNTMT SPRAYS CFF 103 1334.4 .37 H:1 FCRCED CFF 216 1334.4 .37 LP! F CRCED CFF 217 1334.4 .37 SPRAYS FORCED CFF 222 1334.4 .37 CHARG N G PLMPS FCRCED CFF 232 5102.A 1.42 CCRE UNCOVERED 46 7761.0 2.16 5 URN IN PRCGRESS IN I /C LFPER PLENLM 1 41 //e4.7 2.16 UHI ACCLM Eht:TY 190 I 5149.3 2.26 5LRN IN PROGRESS IN UP:ER OST 102 5196'.6 2.25 EL%N IN PRCGRESS IN ANNULAR CST 122 5479.5 2.36 5 URN IN PROGRESS IN LCWER CA T 75 5548.9 2.46 NO 5 URN IN LCWER C4:T 75 1C502.6 2.92 NC 5 URN !N ANNULAR 04:T i22 10522.6 2.92 NO EURN IN UPPER CST 102 10522.6 2.92 EURN IN PRCGRESS IN ANNULAR OST 122 10542.6 2.93 EURN IN PRCGRESS IN UPPER CNt:T 102 10542.6 2.93 NO EURN IN ANNULAR OST 122 l 10555.7 2.93 NO SURN IN UP ER CST 102 l 10569.7 2.94 5 URN IN PROGRESS IN LFPER CST 102 10587.0 2.94 NO EURN IN UPPER Ch i .02 t 10624.5 2.95 EURN IN PROGRESS IN U:PER CMPT 102 i 10649.6 2.96 NO SURN IN UPPER CST 102 10704.5 2.97 5LRN IN PROGRESS IN UP ER OST ' 102 10725.2 2.95 NO EURN IN UPPER CST 102 10506.9 3.00 5 URN IN PRCGRESS IN U:PER 04:T 102 l < N, J 4.3-7 '~~_.,

  • ~.

~~' " ~ ~ ~

y--- -= 10 e 4.;.-; s./._ L s $ /I a 4, , i-v 6., 'g ( ( d t 4.. ,. 4 s, .1 ai e:6 i j _ v =.u- ~ r.e vn 1 i : ", 4 ,,,.,i. 4. OC522.5iO,C". NC SURN 1 N LF:ER C/;7 1102 l j 36.."~f,..- 9. ..e-

VOi..-

J.m-w4 ,." m,. b,,,3 4 l ,n : r l } , i i -..- :n u.a.: . e. x -- m -- e = :l* / n..L-OLnm.1 ! N - CLn se n ww' t a

  • m' e ----

,a**=- e n== ":*.A, un ~'L n's t i N Lt* r On v.t" i iy4 . A c e "4. ** O i'd ww 81w ,6 v, I h, C C. '.:.a. '. ':.CA . V. m^1' :D ~

h. v. 9 =,. c

,..rA =,L:n N I N

==.C<en-ree.l.s1 ? = =.r..:. ev.,e.m 0.:. nc v v. m i l.. e..

3.. O J.n-b0 r.b6 s,,aviLum I 6 *

, Yr. ".. ,'-l".,.- L L :., .OO .r- . - ~ v. 8. t l'021.a 2,06 5 URN I N PROGRESS IN ANNULAR O.t:~ l 122 CC..e.t..t. l.'1 ".':V :.. C.': s- ~* 1 nc4.A. ..e= =.t.:..q i y

N c

/, w-ww 4 l * * ** (* 2. O. ".:. *s *a N L, O f 'a'* A't s' ( /*i e f r-N 'si 6./,., i I 6es n

1.
  • v...1

?. :.. a...:.

1

..A b.

.L.=. v i41 w.=.==..=. L v>.

i . e.s. ro : - m .i

u../ **',"

n : " %,. *.* . =,1 A'v OL'."*.N I N r* N,t4f,1 rn"* N m 4 ,4. .4 .... Ov...

1C-

= s;n,.. N i a,, e nsn.-n s !,i,. 120:e.; 2.:e er-n i 4 t.C4 L,e- --. Cv,. i oa:,c. 2.:2 NC L. N ,.N n i n L.- -. - L.,e, . p' z 3 - -cC I N,

L..31 I N

-n . 22 r- .:.a ia/:c.; 2. n 02 L,e-- Cv'e-i . -,. -c.: 4.0c-- NO =L. N,N e :n i2e n ,..5 sNC :L"n'N I N I /v~ i !~e::n' N L M. 's 4'< ,1 ic.A. 9 . 7, 1 : v., =...: n =-_.._D. ,.. 2 ice g e c. s. '6 5 C ca. 5 '5.C2 CONTMT FAI L ED 1C4 h,p faQ.,," \\ ,. g i, -C'*e? i @ r? Q'$0 J"')_2 # - o _ \\ '. ;. n V;}'I' \\. . c. - v..,...-+= -. e.., -. J, c :. f;..c,,' ;.L. *=v =.,* *,.. *

  • ^ *,,

d*"

  • A,.. e**;,..

e*

  • ,.,s

'qdrif 2.";.. :t - ;,..' u. -e r*

  • q2,.W'" n e

m I . J I. . 0- C M3 g %g.' a .r ep.pe. se g9 als P $ dig =*'r

c_. ... ~ - 0 g ', d g 4.4 Secuence No. 4 - TML3' {

4.4.1 Acciden

Secuence Descristion TML3' consists of a transient sequence initiated by loss of off-site AC power wich' subsequent loss of on-site AC power. Due to lack of cooling, the reactor coolant pump seals fail resulting in a small LOCA (50 gym / pump). In this sequence, several potential sequences are lumped together. These include inanediate failure of main and auxiliary feedwater as well as sequences involving no interruption of main feedwater but subsequent failure of the power conversion system and failure of the auxiliary feedwater. For the base case analysis, both main and auxiliary feedwater are both assumed lost at the time of the initiating event. Emergency core cooling, containment sprays, air return fans, and hydrogen igniters are not available due to loss of all AC power. 4.4.2 Reactor Coolant System Resoonse This sequence is initiated by loss of off-site AC power with subsequent loss of on-site AC power, reactor trip, reactor pump coastdown, and loss of both main and auxiliary feedwater. Figures C.4-1 through C.4-5 illustrate the variables of interest. Due to lack of injection and cooling, the reactor coolant pump seals fail at O.750 hours resulting in a total 200 gal / min leak. The RCS water mass continues to decrease as RCS inventory is depleted through the pump seals. The primary system meintains a relatively constant pressure of about 2000 lb/in2a as the steam generator provides a heat sink. However, the steam generators are losing mass through the secondary side relief valves with no make-up from feedwater. 4.4-1 ...y....

  • he primary system pressure starts to rapidly increase between 1.2 and

-T ~ T 1.3 hours due to :he loss of :he se:endarv side staat: @ e m. senara:5F hea: sink. The pressure con:inues to increase to,the[sid point wi-the# ~ t' it i,} c ~ pressuri er relief valves. Con:inued blowdovn':o the cuench tank results in failure of the tank rup:ure disk a: 1.42 hours. C c=p l e te... ;,.;O:.~.5 steam genera:or dryout occurs at 1.5 hours.'$;During thi's" mt.iniCW". "*~' is a.: ~... E

Ice of high

,. ei pressure RCS blowdown, :he water level in the reactor. vessel rapidly decreases with core u;:covery around 1.3 hours and initiation of hydrogen p cductien occu:-ing at appecxi=ately 2.0 hours. The total hydrogen = ass productica is 450 lbs. at an average ra:e of 0.16 lbs/sec. ~his corresponds :o an overall oxidacien of 23 percent. The pri=ary sys:em continues :o re=ain a: high pressure and sufficien: molten corium is accu =ula:ed to fail the core support plata a: approxi=ately 2.97 hours as evidenced in :he vessel pressure spike and level swell in the vessel. About cne minute later, the vessel fails cad the remaining water, hydrogen,.and corius are discharged from the vessel into the cavi:y at high pressure. Due to the eleva:ed RCS pressure, no water is injected by either 'Td! or cold leg accumulators un:11 the time of vessel failure. ~*inen UE! does inject, it results in cooling of :he upper structures in the vessel, thus providing cooler regions for fission produe: deposi: ion. 4.4.3 containment Respense 4.4.3.1 Containment Reseense - Immediate Release of Volatile ?ission products The following sections presen:, first of all, the results for the first case (see:ien 4.0) in some detail since this case represents :he =est rapid contain:nent pressurization. The second case is presented enly in terms of significant differences from the results of :he first case. 4.4-2

The containment pressure increases to 17.0 lb/in2a following failure of the pump seals and then increases further to 26.0 lb/in2, following cuench tank rupture disk failure. At 2.99 hours the vessel fails, increasing the cental=:nent pressure to approximately 33.0 lb/in2 At the time of vessel failure the water level in the lower ~ a compartment is approximately 2.5 feet which is less than the 10 feet necessary for spillover into the cavity. B erefore, the molten corium is released into a dry cavity. I:mnediate concrete ablation occurs due to " jet" attack during the corium blowdown,,resulting in.aIn initial 3 penetration depth of about 0.20 feet. .c.,' 4 Following reactor vessel failure, the water level in the lower compartment never reaches the necessary 10 foot spillover height. Therefore, once the water discharged during vessel blowdown (cold. leg accumulators and URI) is evaporated by decay heat, the corium in the reactor cavity reheats and decomposes the concrete, thus generating noncondensible gases. The mass of ice remaining at time of vessel failure is approximately 1.5x106 lbs., but this has melted by 8.6 4 hours. With no method of removing heat from the containment, and the continued generation of noncondensible gases from the corium-concrete i attack, the containment failure pressure of 65 lb/in2a is reached at approximately 18.4 hours. At this time, the containment rapidly depressurizes through the assumed 36-inch diameter containment failure hole. Global combustion does not occur in the large containment compartments for two major reasons. First there is suf ficient steam in the atmosphere to inert these compartments early in the accident, i.e., 4.4-3 = 'h-M* P-1h p N OrW G t gyy pm # 4 6 906i dhhe emms 4-b g a** Awun+ as.,

-1 i fla=e :e=perature is less than tha: :ypical of a glebally : !:us:ible sys:e=. Se:endlys high :e=peratures in the reac::: :svitv. due to concre:e a::ack and na: ural circula:icn be:veen :he re:::e cavity and the lever ::=part=ent resul: in burning in the cavi:y which consu=es

he available oxygen over an extended :i=e interval. Thus, the energy release bv ce=buscion is dis: ibuted over the extensive hea: sinks in
he con: sin =en building.

4. I. 3. Cen tai:=en: Reseense - Eeten:ien of Velatile ?ission ?reducts in the ? i=arv Svste= "he basic contain=en response f:: this case, with respect to ice =elt, cenere:e at:ack, combustien, e::,, is inizially :he sa=e as for the -preceding case. The significant redue:icn in at=ospheric heating . =anifests i:self in a slower long :er= pressurization rate. The ti=e to containment failure is about 29 hours as cent:ss:ed :o about 18.4 hours for the preceding case. 9 tac

  • p c. e?.Q

^**' 4 p\\. &= C. ,' L - s. g,. a .1 t-y. o w me t .w e 3 l' 1 is wk G.,~ " w ... Eqi. b ... '~ s,e......:. :~.s TT.;.

  • M. y e.rf /, b **y..'.;?*G;p.a ;.. #'

f ....?...-*..-s- ,w e O f 4.4-4

  • T}

9 1 4 .e-see ea v

  • m=em..

mein. 6.

  • 'e
  • e',-*

eseen g+-

N::2.e k.k-3 kNtAA.P D/iLB ' u.c.----'- SEC i HR l EVENT CESCRI P TI C N lCCCEl 0.0 0.00 MAlN CCCLANT PLM.PS CFF a 0.0 0.00 REACTOR SCRAM 13 0.0 0.00 MSiV CLCSED 156 0.0 0.00 PC#ER NCT AVAlL AELE 205 2704.S .75 EK IN ALL CCLD LEGS (PLM.: SEAL LOCA) 200 2704.E .75 EREAK l F ANY I N CCLD LEG 202 2704.5 .75 PS 3REAK FAIL ED 209 3391.8 .94 LT 10 SEC INVENTCRY ERCKEN S/G 151 3391.8 .94 LT 10 SEC INVENTCRY UN5KN S/G 151 5129.5 1.42 CH RU.:TURE DI S K FAI L ED 92 6A83.9 1.80 CORE UNCOVERED 16 6485.1 1.80 CORE CCVERED A6 C - L,N,o w6 u. C.,, i. .v -e :.. s .s 3 10696.5 2.97 SUPPCRT P' ATE. AIL ED 2 10756.7 2.99 RV FAIL ED 3 10758.5 2.99 CORE COVERED 46 10759.0 2.99 CORE UNCCVERED A6 ~T 10855.3 3.02 ACCU.ill ATCR WATER CE. L: :D 1SS 10857.6 3.02 EURN I N :RCGRESS IN I /C UP:ER PLENiJ.i

  • /

1 41 10982.5 3.05 UH1 ACCLM EMPTY 190 12016.5 3.34 NC SURN IN 'l /C UP:ER PLENLM 1 41 20812.8 8.56 I CE DERL i-D 132 66138.0 15.37 CCNTMT FAIL ED 101 I h.h-5 e a e-am may 9, y ow = y,,

r-m, i. - m t - a [01i '. m

1. :d 1:~

' ;l.. e ", Lg 4 ~. 5 Seouence No. 5 -'T,,E -U N.OdUdEU N a.. ~4.5.1 A :iden: Secuence Descristien T,,E consis:s of ' a ::ansien: ini:ia::: c:her :han. less of eff-site ~~

i*;La'.'.',
*.. N2.:'i.v 'e e W. '
  • 4.2 e

power wi:h aute=a:ic reac:c trip and loss of = sin and auxilia y feedwa:er. AC power is available and, :herefore, emergency ecre c.;) ling and containment safeguards are available throughou: the a: ident. Although sufficient time exists for operator ac: ion, che base case assumes human or equipment failures prevent proper charging and saf ety system operation. I:, therefore, is a very lev probabili:7 even:. Higher probabili:y sequences are dis:ussed in section 5.0. 4.5.2 Resetor Coolant S sten Rassense "his sequence is initiated by loss of both =ain end cuniliary feedwater, followed by reactor trip and reactor pu=p coastdown. = Figures C.5-1 through C.5-5 illustra:e the variables of interest. Following loss of all feedwater and reae:or scra=, the primary sys:em pressure decreases momentarily folleved by the actua:ien of the pressuriser hea:ers which maintain :he pressure a: approxi=ately 2270 lb/in2 The water level in the pressuri:er increases during heat up and volumetric expansion causing :he pressuri:er to go solid around 1.0 hour af ter accident iniciation. The primary system pressure starts to increase be:veen 0.71 hours and ~ 1.3 hours due :o the loss of the secondary side s:eam generator heat sink. The pressure continues to rise to :he se: poin: of the presssuri:er safety valves. Ecwever, blowdown through these valves decreases primary system inven:ory and with no makeup both the primary - system pressure and l'evel begin to decrease. Therefore, the pri=ary IDCOR.4 4.5-1 n.,-.

I. system pressure.stablizes at the PORY set point of 2350 lb/in2a with continued inventory depletion and core uncovery occurring at 1.60 ~ hours. As the water level in the core continues,co drop, the cladding i f ~ ' :. camperature begins to increase. At approximately Q31, hours,- the-fualdi nodes begin to approach 19440F -and the metal-water reaction initiates significant hydrogen generation and further core melting. NR. ~~ Total hydrogen production from in-vessel Zirealoy oxidation is 448 lbs. The average production rate is 0.17 lbm/see and the reaction-is equivalent to a total core average clad oxidation of 22 percent. The primary system continues to remain at high pressure and suf ficient molten corium is accumulated to fail the core support plate at 2.73 hours. At 2.75 hours the vessel fails and the remaining water, hydrogen, and corium core discharged from the vessel into the cavity at high pressure. 4.5.3 Containment Resoonse - Immediate Release of volatile Fission Products The following section presents the results for the case of volatile fission products released at vessel failure in some detail since this represents the most conservative containment response. ~he second case is not presented since the containment failure is not predicted for this sequence. i The centainment pressure remains at 15.0 lb/in2a until quench tank rupture disk failure at 1.1 hours. The containment pressure rapidly increases to 23.5 lb/in2a but is quickly suppresssed as the containment sprays, air return fans, and ice are available. The containment sprays take suction from the RWST until successful recirculation realignment occurs at 1.5 hours. This pressure IDCOR.4 4.5-2 E e_ m auw.,-,gw.= 4 =h 9 9e

  • e *
    • "F 8"* * "***W*"si--**

e

suppressica reduced the pressure :o abou: 17.5 lb/in a un:i1 vessel f ailure occurs at 2.75 hours wi:5 a ecrresponding pressure increase :: 22.5 lb/in2a which is quickly suppressed. As :he ice cen:inues to =el: and RCS inventory is les fr== the pressuriser relief valves, the water level in the icwer ec= par:=en: exceeds :he necessary curb height required for spilling water into the cavity c: approxir,ately 1.3 hours. Therefore, when the vessel fails a: 2.75 hours the cavity is flooded. This flooded condi: ion li=i:s core-cencre:e ablation to the "j e " a::ack resulting in a 0.19-f oot penetrati:n depth. he fleeded cavi:7 resul:s in i=ediate quenching of the coriu=. ~he re=aining ice a: ti=e of vessel failure is appr xinately 1.2xic6 1h=. At 5.02 hours, all of :he ice has =el:ed and centai=en: pressurica:ien begins. Following ice depletica, :he cen:ai=en: pressure rapidly rises to abou: 20.0 lb/in2a However, the containment sprays continue :o re=ove heat fre= the contai=en: a:=osphere. ~his heat re= oval rate catches the heat decay at approxi=ately 7.0 heers. '"here f ore, the con:ai=en: spray hea: re= oval rata is =cre than adequa:e to re=ove decay hea: and the contai=ent pressure continues to decrease, thus precluding contain=en: failure. p 9 e,m, Pt g - _.i m Ei o c. O ' ~1.i Q)yk,;('QQ..uugGJd"'yU.' .i t O .-j-u .e g.2 IOCOR.4 4.5-3 ene am. , gamin, emm me e emm 9 PS >-ne. -e 4 w. m.. e g - eW w =- e w -es eee.i.. .u-.

y_::.e L. 5_:. FD"I/LhAD ~ n q W Il _ %A 4 l 4. - L v-N -= .L. SEC l HR l EVENT DESCRI P TI C N. lCCDE! 13 O.0-0.00 REACTCR SCRR.i ..s 0.0 0.00 MSIV CLCSED 156 0.0 0.00 H:1 F CRCED C 716 0.0 0.00

  • LP! F CRCED CF 45%...
2.,,. _....,,~._.e.-- 217 0.O O 00 AUX FEED WATERiFCR'CEfCe f 224 0.0 0.00 MAIN FW SHUT CF~

22S 0.O' O.00 CHARGIN G WPS FCRCED CFF 232 2539.7 71 LT 10 SEC -1 NVENTCRY ERCKEN S/G 151 71 LT 10 SEC INVENTCRY UN5KN S/G 161 2539.7 3987.1 '1.11 C/T RU.:TURE DI SK FAIL ED 92 4006.6 1.11 MAIN CCCLANT PLM S CF-4 40C6.6

1. i 1 CONTMT SPRAYS CN 103 5400.2 1.50 REC 1 R C Sh a.M ! N CPERATI ON 121 5+0S.2 1.50 Rd.C2 R C SWIT Oi: MAN CN 220 5411.6 1.50 CH FLMPS IN SUFF NPSH 153 5411.6 1.50 HP! P Lht:S IN SUFF NPSH iSS 5774.8 1.60 CCRE UNCOVERED 46 9540.5 2.73 SUP CPT PLATE FAI L ED 2

' ) 9901.3 2.75 RV FAI L ED 3 9903.5 2.75 CCRE CCVERED 46 9903.6 2.75 CCRE UNCCVERED 46 9905.3 2.75 SURN IN PRCGRESS IN I/C UP ER LENLM 1 41 9907.A 2.75 EURN IN PRCGRESS IN LCWER CSi /5 9998.7 2.78 ACCLAU ATOR WATER DE.:L:7ED iSS 10083.6 2.80 NO SURN IN LCWER C# i /o 10095.5 2.80 NO SURN IN I/C UPPER PLENLM 1 41 10:03.5 2.81 EURN IN PRCGRESS IN I/C U::ER :LENLM 1 41 1 10127.5 2.Si UH! A CCLM EMi-Tf 190 10263.3 2.85 NO SURN IN I /C UP:ER PLENLM i ai 15086.9 5.02 1CE DEPLETED 132 r k L.3 h -=. .---...=w i es,m. +s _.4 ..y,,,,

    • ge m

v-r

4.6 3ecuence No. 6 - AD

4.6.1 Acciden

Secuence Descrietica AD censists of a large break *.00A (10" dia=eter). E.n.i.:idcr wi':h ' , s w /r~*> s,. t failure of :he energen:y core b,oolipi;:sys:em..( CCSr,\\, da::::he s g: s.s. e subsequent a n.3.s w - injection mode. The ICCS tencinues :o be unavailable in the recircu1a::..cn m e. Conta ta=ien: sa:eguards sys tems are ava:. lab.le.. -:.~.;

d..'.jg$.c..dW="~;~"g.;i.~:w

~~..:.~e

g.,,

w throughout the aceiden:. 4.6.2 Reae:or Coolant Svstem Reseense Upon initia:icn of a 0.f454 ft2 cold leg break, the rea:::: is scracned, followed by rea::or pump =cas:down caf au::iliarv feedwa:er startup a: five seconds. Figures C.6-1 :hrou;;h C.6-5 illus::a:e :he . variables of interest. Inmedia:ely folleving break ini:ic:ica, the primary system pressure rapidly decreases to contai.r.en: prsssure. The decrease in reactor vessel va:er level resul:s in core uncoveri abou: 0.58 hours and ini:ia:ien of hydrogen produccion a: 0.70 hours. Total hydrogen productica from in-vessel Zirealey exida: ion is 370 lbs, 'at an average rate of 0.19 lbs/sec. '"his correspends to an average clad exidatien of 19 percent. The core con:inues to hes: up until fuel mel:ing occurs leading to failure of the core support place at 1.62 hours as evidenced in the vessel pressure spike and level swell in the vessel. The molten corium falls into the lower plenum and fails the reactor vessel a: approxima:ely 1.63 hours and the remaining water, hydrogen, and mol:en corium is discharged into the cavity region. IDCOR.4 4.6-1

i L. j.-. 4.6.3 Containment T.essense - Im=edis.te Release of Volatile Fission products The followiorc section presents che'results for the first case (volati7 e fission! products released at vessel failure) in some detail s since this case represents the most conservative containment response. 2EFe tis n@+T The second caso is not-presented since een 1 E s l Hu. - i predicted for th s sequence. C Immediately following break initiation, the; lover. compartment rapidly...... c;- .~ gggsww :.a:. pressurizes as the' RCS inventory is discharged. This immediate pressure increase leads to actuation of contai= ment sprays at 2.1 s,econds. The - containment spray takes suction from the Rk'ST until 0.39 seconds at which timet successful spray recirculation switchover is ychieved. At 1.63 hours, the reactor vessel fails and the containment pressure increases 19.5 lb/in2a and the lower compartment temperature reaches a peak of 2000F. The air return fans, containment sprays, and remaining ice reduce the temperature to about 1600F. Since the ice has' rat been deplaced at this time, the temperatbre response in the upper compartment remains somewhat constant. The water level 6 tb - at approximately 0.3 hours. Therefore, at the time dr. ;,1 .. lure occurs the cavity is flooded. This flooded condition-limits core-concrete ablation to the " jet" attack only resulting in a 0.17 ft penetration depth. The flooded cavity results in the inanediate quenching of the corium. The ice remaining at time of vessel failure is approximately 8.5x105 . lbs (about 60 percent melted). ' At 3.21 hours, all the ice has melted and containment presrurization begins. Following ice depletion, the containment sprays continue to remove heat from the containment IDCOR.4 4.6-2 .. ~ -. w$ w. -wu%..w....<

i,. a:=osphere as indicated by the depressed upper ::=partment ta=pers ure. This hea: re=cval ra:e =atches the de:ay hea: at apprcxi=a:ely 5 h:urs when - the =an'--- con:ain=ent pressure reaches 21 lb /in2. Af:e-vard, a

he contai:=en: spray hea: re=cval ra:e ex:eeds :ha: of decay hea: and the ontainmen: pressure will decrease,_:hus precluding cen:ain=en:

f ailure. I" <L ~ ' .r s. 3 This sequen:e results in the mos: rapid loss of reae:c coolan: system e inven:ory in ::=parisen to the e:her :ases.. Theref:re,- :he :::s... heating history is-illus: raced in Figures 4.6-1 :hrou;h 4.5-6. hese

e=pera:ura :::: cur aps represen: a vertical see:irn :hr: ugh the :cre with both radial and axial node regicas indica:ed. A: :i=e zero, :he te=pers:ure dis:ribuciens are indi:2:ed en Figure 4.6-1.

l==ediately following reae:c scra=, all core node :e peratures correspond :o the satura:1cn ta=perature and pressure :..a pri=ary sys:e= as indicated in Figure 4.6-2. This te=perature equilibra:ica of all =cre nodes c ontinues to follow :he satura: ion ta=perature until ccre uncovery occurs a: apprcxi=ately 0.58 hours. Following core uncovery, :he core tempera:ures increase rapidly as the cladding-stes= reaccion provide energy and hydrogen is generated as indicated en Figure 4.6-3. Referring :o Figure 4.6-4, the temperature distribution a: 1.60 hours indicates :he te=perature profiles as :he upper regions of the core begin heating. Approximately 0.10 hours later :he lower core support plate fails and the vessel fails at 1.63 hours. Figures 4.6-5 and 4.6-6 illustrate pos: vessel failure heating. These nodal ta=peratures are cnly representative of nodes tha: have not reached the =elting te=perature. IDCOR.4 4.6-3 9 s ep W "d** We==.s eeWir

  • -epsw*v A haup d'

-"=ehmi e Aw wwhe% .g

n ; r e E.6 '. b.ijguWJuuwg.-,,. r) AT QvMy,. 'iCURS =M @ ~ CORE MAP (deg r.v e-t 00 -.c. :..+ :. a:w.120 0 -t - . ' - - ~, . a. ~ =. =-: :=:.. -. 0 w - ----. . w<cnc_ p..-. 'y ,gGO-1400- ~ m-,' s, 's ~, r_ i 1600 - 1500 - i\\ j l l - --~~. \\ ~, \\ \\ \\ \\ p' / \\ s \\ t t y \\ \\ \\ l I MOO [ I, l l i i c-I s_ \\ t I I 8 g e i '/ / 8 l I I* l\\,' t 1 1 I s-l g I I L i O r l i 0 C t LU t g- ' t.c C c-t i

  • *** t Q

\\ t I I l{0 w k I \\ ', 5 '\\ \\ 0s / /o / \\ Iw I

==' \\ Q \\ ,.**r f,,l. l \\ \\ \\ s l \\ ,/ %s - - \\ 'm. l \\ x m. \\ ,0 \\ g g i QA / t, x 'v *^ i ~ l a 1 r I t i I I t t I / 1 g I ,f / l ./ ,1 ,1 1, s -. ~ ~'% 's \\ l \\ r \\ n., I \\ \\ ^ l@Q l 400

/

/ i N 1400 - ,f t t l s s N, i n- 's, A - 1200 ~, ~' 1 ~, l 's. 1000 1000 l -s -s -4 -s -2 -1 a 1 2-3 4 s s l RADIAL NODE "g \\..' s h.6 h "*BD'O#'tM'g W'8* v-w-.e*g,,,... -Tv p

.4._.. .2-c- ,o - -.. ~ -S i i4-( U r u, a r, - - g i

a..m

/. i, ; W,._ __ ..'v i Liv,s_s m LV. iv:-.i t \\ / .s

=

o- ..x, '. s. t. ,,,.-,.i

t...

-3 g.

4. g. y.,.,u, w:..

c- ..,...: - m 2. < ~ . :.- ~ - - - 8-W n'1 C.o. Nrt"b-s u nL w. -c-O v mI .,C. ../. < X :n - .m-1 m. ~6 -5 -+ -2 -2 -1 0 1 2 2 4 5 5 NUs:a n.- .=s t. 9 l.4 ! a / b.2' = :: s .I = 'Muu"1

  • + espostme

,,,9 ,m -m-

n = h.6-3 con!. N,i.,ap ceg r) c! r i N..,i t = .0 0 r o, y trs S- -- s f i c un C j,, ,/ 99--.. s s - 7390 l, j -- ~~?. - W, ' \\ ~, \\s %, \\, s N N-o- l ,V 7 f ~f lD 0 ~\\' 's 's i l l

  1. 00O

\\ \\, , s, .h.,.\\,,m,~.<. ns.w s l ,u i i t. s '; {\\ ' - ~ ~ l n i s i,, i e e-i I 'O I s g 3 4,': !o N i 8 . 't v :. ....e.. io -g : 5.,n.. =.c :

  • "'g

,i. l l s s g '\\ \\_ 2000 2000 l l i n- , O., \\ s A s s s s - s ..c-s, s ,i s s \\ -1 0 s s a s s ~~ -_.' ,'/ '. \\, \\ g3 g 4. N N N, v' ~ s O,' emus ~ ~ ~ ' - - - _ _ _ - _ - _ _ _ _ 3.,q .*~ X N ,/ 1900 ^ \\ 's, s..y e 3000-j ~, ~ ss, s 800- / ,-'y N m. - ' goo /

...-.......o00 s

' 00, 5 400 u. ~~~~ -......-........... -----------...-----._-..... _'s _'s _ 4 _s -2 -1 o i i 5 I 5 5 RADIAL NODE 3 ,e h,6 6 -.-..,_.=*-.ee.., s,. e m. ,,1 ..e-e-e ese m ammmamem-e. em.mp e e. 4 + - ~.

.I .-g_. I l"""w %""* q

=== h / ,e, ,* A ,*,I O -l

  • l ;\\ ;,,=== --

!.Cy e

===, 's R \\ p,s i /.,. r'. [ (,b~.~.1 ,.m t :VLi'V \\ucy I e,1 1 i W.-

  • e e

e__ C-N e m* r, s m.,. ' ,a n? .\\. ' p..'.. t. ,w .o' , e. s . e n'* 0.t w O O,' .f- ,O= p

== X 'e9 ""' / /. / \\ / ,/ < \\ / \\ / ,/ \\ 5 \\ p g .O - \\ / / N, 's 5000- ~,. / 4 / ~~~--..... . -o,,/ 4, s, ., 0 O - - -. - - - - _ - - - - - _ _ _ _ _ _ _ hgo ' s s s A 's ,'s,,,,,~.-______-...2, - s n- ,,.______.2000.____---------_-_....__.__- ~, ~., q,... - - - - _ _ _ _ _..).. n. Q. _ _ _ _ _- - - - ~.. _ on00. / e p ej i 4 2 "O "O "4 "'* J "" 9

    • 3
  • =
b. 6-7

--y w. e y 7

n c=- u.6.- CORE MAP dea F Al -l i ME= 1.70 HOURS _d C

  • ~

/ 's e y m, #% e s,.- - - n c m $3-

; j r. m e. ; 7 *. 6-C c
n _

I. Ub b c - L-o e_ w -. , f,': =_..,. M/M.-. s ?.,3 a; *

2... s b*4* 'a' 7da.il ' ** 1r e n.'r h ' W*d.*L ' 5 i....r O*~

CZ J O, < d-X< r-M- ,r / \\ / / \\ / / - \\ p / /s \\ f f /^ \\ / <* #

f

\\\\

\\\\,t,0,(,.. _ _.. _ __ 5 0 0 0._ - __ _ - _ __ __ _ _._. _ __ _ 5 0 0 0 a-

,o,,,...___...._..__-_...___.__....__-__......_..__...,,, 0 0. _.... _ _ _. _.__ _____. _ _..... 0 0....,,- 00 00 ./,*' , ' ~, s -6 -5 .-A -3 -2 -1 0 1 .2 3 4 5 5 RADIAL NODE .g , 6_a 4 ...m._.

i e e .?J..-e-. .' C ~ b (m ~.- '\\fi.p.a..'3 ( P.O. C ~\\ -. b r, s.S.. v'; ifm . ~ ~ - lm, '..% m t o ).- ' - .( v - .,o ,u. l i . s i >< s. v .vv. / C m.. S m- .i _.,; m....__ - ... - -.. =. .s - s'c*- d 3 e-X< n-t \\ ,/ s / N w%'~~ --- ------------------------------------.--.-- --- e-.e . ~. - ~ - o 00'O ~:-: - 2000- ~ g:,% ;, ',

~~...-

~,-~% ~,. A%%%\\s\\% [ -2 -1 c 1 2 3 4 5 s -o -4 -,in.L NODt .,nv l e e

1..6"

-y a = g= ..4., .u. w.

x:le a.6-1 NAM I V IVI, e^,.D 6n ,sv l SEC l HR l EVENT DESCR!.:T1CN !CCDE! 0.0 0.00 REAC CR SCRAM 13 0.0 0.00 AUX FEEDWATER CN i54 0.0 0.00 MSIV CLCSED '56 0.0 0.00 SREAK 1 F ANY I N CCLD LEG 202 0.0 0.00 PS SREAK FAIL ED 209 0.0 0.00 HPI FCRCED CFF 216 0.0 0.00 LPI.CRCED CFF 217 0.0 0.00 CHARG N G PUSS FCRCED CF 232 2.1 .00 CCNTMT 5: RAYS CN 103 GO.9 .02 N%IN CCCLANT U 'PS CFF 4 318.5 .09 UHI ACCLM EMPTY 190 542.2 .23 ACCLMULATCR WATER DE.:L::. : ED iSS 1409.2 .39 REC R C Sh i:ed i N CPERAT1 ON 181 1409.2 .39 REC R C SWITCH : NAN CN 220 1415.7 .39 CH PLMPS IN SU. F NPSH 183 I 1415.7 .39 H:1 P LMPS I N SUFF NPSH 185 7 '2080.5 .58 CCRE UNCCVER D 46 4070.7 1.13 SURN IN PRCGRESS IN LCNER CMPT 75 4155.9 1.15 SURN IN PRCGRESS IN I /C UPPER PLENLM 1 41 45S5.8 1.27 SURN IN PRCGRESS IN UPPER CAPT 102 4652.3 1.29 SURN IN. RCGRESS IN ANNULAR CMPT 122-5683.0 1.SS NO SURN IN LC#ER CMPT 75 5816.1 1.62 SUPPCRT PLATE FAIL ED 2 5876.2 1.63 RV FAIL ED 3 5896.7 1.64 CCRE CCVERED 46 5S96.7 1.64 CCRE UNCOVERED 46 5897.4 1,64 CCRE COVERED 46 5897.A 1.64 CCRE UNCCVERED 46 5931.9 1.65 EURN IN PRCGRESS IN LC#ER CMPT 75 6425.0 1.75 NO SURN IN LCNER CAPT 75 7075.8 1.97 NO SURN 1N UPPER CMPT 102 7082.0 1.97 SURN IN PRCGRESS IN UPPER CST 102 7106.1 1.97 NO SURN 'lN UPPER CST 102 7177.7 1.99 SURN IN PROGRESS IN UP:ER CVPT 102 7177.7 1.99 NO SURN IN ANNULAR CAPT 122 7203.5 2.00 NO SURN IN UPPER CST i 102 .m k.6-2.C

  • ~

=... r.

~& ~ a k. 5 ~~- . T'. q' - Vu~.,"~u) Al I k '.'.O A i4 h.h e AA' ' 7J !. O

  • (,

ltt.; h,iL*'y0 M C i: ,~C I w ~ } l 7 .C (.* I, ' ; =. j 7\\,'T.Al~.

n..."l'[=. f = ~4 } C e iU l e.""..' 7 1 s

}4.CC

, nN i d.- ". ' un = ?.:. i.,4 c.h, r.,..vien

's ' e.--

.44

./46 ..~ I==.C.J i..e au 1 gI, ~7. s4 .e Nr m n N L u c.,:. C.s.: w. :.. //i 4.~ . v = en. .za i .c-- l ' "/ / *s,,.

7.. *. c

= L.=..>I !.sI

==..CF,=..ree, l.sl m.e.u ba,_n.=. n.:=. t

  • a =1 A

[' = u s i l ///=.9 4.4ic NO :, nN, I N, .NNU.., O.4-i i24, tan e "* c.1. '^:f 4. I :w O. f M.M t at 9 + .==CL.a.c.e.t. .i N n4 4.A4'c, n.=, .c. i 1aa sa a. // .v 4 sn ";l:4"4'..C 9. *. O. tNV = f '.=..'N' I' N m' N'N't 1 n* n* ^

t. 4="i 1 *.*.*.")

9 / _v v 7851.0 2.12 SURN I N PRCGRESS IN ANNULAR 04:7 122. / c. 4 4. O 4.4*e n o = v n N, I44

m. o s..,anuver:

n o i aa Ov. a a44 c c0** 9 e. 9.:. = L"n-'N *t.t4 =. =..r. c =..c t e a I l nNtA'L9, nn C. e,: i 1 S a) a a a i a SCa2.5 2.22 NO SURN I N -ANNULAR Ov'PT

  • 22
C. ~/. ~:.

7."4 O.f s'.:..N I.N ... C ":. T.T. I.N e" "u"sb~ 2.n" w".c. 6 'a '.:.7 c. .=. Q c 7. n., 9 s: HV = f..=. nu

e..U,

.a ua 4,,nn(*.A; gv:i.==1 . i uu i .=.** =

7.. a -

=Una s av lnV +1a7 .==.Ce=r..ee t.U< = Uut ni n v't... =, (9..c.. t i... 3 C. I .,- i N C =-.. N, I N

e.,,el.

C,,e i i2e i =.-.. 2.ao iac. vn .n a v..sn .t .. /,- =y=..q [.u .= =. c. c=..r..e.e. g it e.1s.yg r =. m..= 1 3 j a.

. o e

u. 4 .C ?. C., d = ".).. "4'* Q,. .A,f ^ O. f,.'* n kt ' Af cIi bft T r*.n* .= "I" l 7.7

  • I V

n t.. v C *2 0 4. *.: ".).. *.*. C = L'" Nf f.A1 c" O. C v".:.'.T. *.* T n i C I N n* a'Nf 1 n* n O.C i 1 *.*.*.3 k v 22*.' 7

7. 7.:

.NO : URN I.N ANNU.n*.:. C/:T .m

.3.4 4. ~

e, -..M N.i. enCGR =2 .43.. , N

n. cN....r.

O,,e-i .3 =c = i n Vur i4. S242.4 2.29 NO SURN I N ANNLU" 04:T 122 .= v.a c. a , nC .=L=.q c N.= =. e.C.R =.,. I 6s elln L" E. Ov>e-i i4n. us I w =;.9.o-4..2. N,O =L..s! IJs e,L,.s. - Ov,e-i i22 .uu .t n

c. *. i 7. 7
7.. = ~.:

.NC.: URN 1.N I /C U:. :2_.9.08 TNU/.

  • at

.=.yn N l.q .=.=.c.C"..:..e.e j g i /e.. c = =.=. => .r..u. g..{ . c. c.. 2.v - 7..=c i s v. i i 9521.4 2.64 NO SURN I N I/C UP:ER PLENUd 1 41 9540.2 2.65 SURN IN ::CGRESS IN I/C UP:ER PLENUA 1 41 9692.9 2.69 NO SURN IN I/C UPPER PLENUd t ai 9695.2 2.69 SURN IN PRCGRESS IN I /C UP:ER PLENUd i 41 9757.3 2.71 NO SURN IN I /C UP:ER.:LENLM 1 41 9772.1 2.71 SURN IN PRCGRESS IN I /C U::ER PLENUd 1 41 9822.2 2.72 NO SURN IN I/C U:.:ER PLENUd 1 41 9905.2 2.75 SURN IN PRCGRESS IN I /C UP:ER :LENUd 141 9942.6 2.76 NO SURN IN ! /C UPPER PLENLM 1 41

c. c. =,..=

.= >v n.y I,e, =.=.cc=..ree i.N [/c L==..=. =rryua A. i i 100:5.8 2.75 NO SURN IN !/C UPPER PLENLM 1 41 ...CGR.e.t? I N l /C Uf.::..:..:'-'.NLM

  • 11 100'S.:

0 7o. . URN I N .s v h 6 :.2. m ge eMW4- >.d.I** e *.. , an. ei e e ,a +s+ .+e.

U Etm ,? t t il ,8 )a, 3 s h' L.,g @Q'r C_. 'c a.. ~%- 0dl. 33;_2 3 2 <n- .is l J %g' l t tlU _ ;r l>11Z[-

t I

l-O2 ,UoOl oloLt}r tt /i g l i i If .O.tM.N N.U1 Z0m>tz z ( 3' n( t (- IZ dN.1t }. - )o (F t E Lin 1l$ ] )1l g; - 1 ii r'.- ttyd y \\U 3(n.at .I-ti I .ONNO.1 N.704 i3Ez _2 LrO tZ3 t tt i/ i L. lll l l il n.4 N.Gt ZO m3r2 2 U.nntt. !r. It IZ37 Ol1' - t 1_ t 1_ w s 1- ) ) ir htt _ z N U 3.n n. h i n_ tZ 3 OPtIs.o N.Gt t f3tz z nEO 1oo ( 1 l' w a lt 1- ) .fl l OtI4.Il' N.1U z0 m3tz.z U 3Lnt( t. ( t. tZ37 GE l' N r .iE i 1-l

l U3tZ z IEObtttloo. z NU J(L.nti slZ3 1-t S

t (_ .OPOJ. w N.UO r it L_ i t i In In l 1 Ol'tO.O N.Oe 20 u3tz z U D.(tIhs t _f tZ 1-f I f l 1 e wn lt n G3iz z

n. DO iMto _z

\\U Dt.hi sn n_ iZ3 t .- OoNN.l N.ON t G s t at 1-1t l s n U 3t n. i E tJltZ37 1-t( i - OooN.)G N.Oln )' zO mJtz z tt i L t l OoOo.)G N.Oo GJ(r2 z n0Obhttsoo z NU 3.f1ti tz3 4 t t t f. t1it .l i l Il n l ODno.i N.Ot zO nDtz.z U 31ntt ( nJ tZb i Ot i S s w r ..it s ~ 1-n l t3t2 z nEObiMto_z N U 3.(1 I.at i ( t Iti n_ tz3 It ( Osl'P.H N.O)G i i I-il l 1 n l l (ti t _1tZ 37 1-t l z0 lDtz. z O J(L1lt Oitsoo.O N.OO n i t e r nn InObt(n. z N(1 D.fn1( n_tZ3 l3rG. (Z. f-I CEr tUof P.OC O t - 1 L - sM i 5-8

  • i1 S

o O 3(n tn s_tatZ37 i UI z0 mJ(t2 _.z O(Po.G )' O.- t t L.i s I- ) l: Z 2 ttObtttsoo.z NU D.inttlt L_1 8 Z 3 4,- t I 1 I3K I .- OOe to.P P.OP a i I tr l 1 1 n U 3 ( n. t i nJjZJ2 4-h zO iJ(Ez. z - OOPo.M M.O4 t n L at l nI (3t2 _ z nKObh1M.7 NU 3t.tnit ti L_I t Z 3 t I e t eO.n.)f P.Oo s H r 14 l 1-1 t LIlZ37 2O lJ(z. z O 3Ln. a n (_ ( t n t wONi, P.Oo i 1-s.- t l: l .-.OPN..- P.O0 n3r2 z LEObsoM z \\U DtLlt t(ti 1 tZ3 1 i t E ht i 1. i 1-1 1 Il .-.OJ-.o l' Ot zO mJEz.z U 3Liht L tZ37 4 t t tt (. i lt w Il \\ U 3 ( n. e E L_i t Z 3 l I_ l e.On..O M.Ot U3tz _ z trObhMi _2 e E t It w n e L l-n t s LJlz37 1-I t U 3tnti ..N.O M..O zO m3tz _ Z t

t. a t i

-) l n NU.Liit (ttt ( t L_i l Z 3 l-tMM_2 n3tZ _2 LWO i i O)2.O P.e. i i ). l r n 1 l .n_ tZ37 1-z0 u3(z _ z U 3tntst iiIi NOo.o P..- t t i t 1 Il l .z NU 3(nhi t_ lZ3 1-t t ti t i tI htt .-.Nos.O P.M i3t2 2 tEO loo i L. lt 1 l O 3(.nhE.n_tZ37 2. .No..D M..M z0 mJ(rz _z t ( i L 1-l Il i3rz 2 tEObbti _z NU 3(1nttl.r L ltz3 1-t t (_ . No(~ M..P t .. i i n lon - 1 1z. 2 O 3L. ht. I1 (. (n zO i3Ez _2 ( .N)GP.o M..N t n_ 1- ) lt n 1 (3iZ _2 LEObiMi _z N U J (L L i E t_ l Z 3 f( t Et f t t

  • PGN.P P..o i

U t n 1- - 1J ) 1 l l U 3tLlt H_bz37 4.- t(hi - eIQN.P P.i zO n3Ez.2 f s 1l 1 I e+noN.D N.Nv ._Ot oh.n_i a3 PN t' it E a 1 l 1 Il .. e t.4rN e i tt s 'i 'i

s , ~ _ u e......, .. ~, -. %;* d '*\\ Y'~ ? '5',,*. "t i.E. 5 )*,,' j,fl?$' ?.:,'J. $' ': ; Ab = * .. a.s.,s.ra. e-APPEND X C 9 9 4 4 S O O e 4 e m a

C.1 Accident Signaturns Accident signatures are presented for each of the base cases analyzed in this report. These signatures are generated directly from the MAAP progrs= plot files using prog-s=s developed at VA. Figures are arranged according to case utsaber as described below. In all figures, the lef t axis is used in conjunction with the solid curve whereas the right axis, if present, is u' sed with the dashed curve. An attempt has been made to group multiple plots on each plate to show transient interslationships between variables of interest. Cases are identified as described in the report body. c - ,,..._,"s.- s, Case 1 S.,D (F1MAAP) 19 p Case 2 5 H (F2MAAP) 2 Case 3 S2HF (F3MAAP) ..,. u. TML3' (F4MAAP) Case 4 ~ Case 5 T23ML (FSMAAP) AD (F6MAAP) Case 6 4 i i T IDcot.C C.1-1 .. y _,;_--

u D :_- i m,,.m,.,. e, o oa = aj i I .s. i =o .e e e. o, ..g _ e .a.. - 1 I .c. o. t.: :; .-:..o-6.z.*4g y,\\ , =-*. w g DCo. U%' d. N k a g-N; u g \\ \\ a1 \\ - xs o _i 'I \\ O W S I w J I I 'c.c c.s u u u u u u 4.c 4.s TIME Chr) a e. asJ P ~e g, a l l e' I /r! g' =., i 1 i. E .a C%) Al j ,/ "I ) a. O i i - e ,,., g - t e i / a. 4 E*, 'a< m ~g-t' l,,/ I

== / g*< at O 2., i / v ,o o g. ti =m vo, n a / m l = e. ., s. g g.'.._ a., e, l , -- c' l s, I a.s c.s u u u u u u a <,.s TIME Chr) .u..w.. C.*-2 y

  • e

....i

.~..,_ -, _.. c.,.., 2D..M A A-r: r = w,. M u i t i i i --e.,.. = ,., 5 't. li ! I N. ~@..J.ih. it d M,,. I., " > i 0 .l g f.g = = - w n v.. g i n n t ~, n a .u am .i .i. c n >t i r n .l M bd.pt kphy h.,;,.g f;f

  • N*'

4 O$, 1, j ! l: 9*".'f'dii$ siss."*** ~ ~ 3 < a. -- i, I., as e .c >a e e. w2. ; - i. i. j l ll. w c u . }. a< ll o e i. i i,, .e l 1 i =,. U m.: <g (< ..,i j g C!. s' e { l s O =.. 1t e. u u u u u O O .u u u TWE Chr) s e . u ,i \\ s ,g s, ,o s-i a ,e t ., sun 3,u '.----- -...u 4 s 's d.' \\ .. a. .g m2 tm g as e-O , 2. 4 v o ,~ n., ? g; v 5." l 'N

t m

o ..m e w ,/ ,. a. v. 3 o.- ,n 7. w e (, i,,,., 'g , ei. s, _ = e.t. o 'u u i.s u 2,s u u u b d TWE. Chr) 9*, c.1-3

1 -.e. e -..._.t + 1 \\ amm i= ("i/gk.i 3.' D./. i / T

  • =.o o

I g .....a...... (- r P' ~.......t.......!.......I

o. )

i I [ I [ ,r-4 t } 4

/ ;

i mi 1 5 ~- t, ... _... 1 a i

r. e >

n= / i i i t- ~ L e .,i pa w q.; : li

  • s b-

.,p I

r. 2,

1 l in y ,e r_ <.e. ? } } } 3 i i ..v V >.< l I. i ~ l^ i .~8 3..- 1 I=M l . - ~ + v. 4: 1 1 n-k 1: i i l [a o. i i i f a , e, 'u u u u u m.s e.s wa tu u.s

u

=.:

u TIME (hr)

=

i, e

I I I I l l l l = Id I t I l t t t t g l -k .P I .w'% 8 i n.- i r e-8 O

==< l .44 w a. w e c - 2

e.

..a -: .4= w g. = a. V :] l;l o l=V = = ', O v, .8 , g :n y i > a=, 1 ,*v .o 2 v ;- ';l i.......t.......i............. 1..... i...... i......i..... 1....... i. i l l I I I I I I i a, .u

.s u

u u u.s =.s ka tu tu

.s

=.s

u TIME (br)
  • ,p C.'.a

n== .12 S2D FtMAAP 8 i l 1 I l l l I f I Y'N-NNe.j*.n,~k n,!.M b i ~% I 1 J. l l o Jc 1 N ( .M ~

_-,A i

h?!Q. ilt h..e uw o

i. -n v-g gj y

O v es h !. < )[ j ft4 hu. L "'i * ~" w ~ s-m 'o.s u is u u is.s u.a U.a su u.s zu

=.s 24.s TIME Chr) 1.

nll A, \\ a-.! \\ l l I i Js, 9:, E=.i \\. \\ 4 : WE' \\ s e i a.: T <e. 4 : 3s! * ~ .l w ( \\ = . 'u s.s is u u is ts.s sa u.s tu ro.s

==.s 24.a TIME Chr)

  • h$$e C.1-5

-s... .-3-. QQO CT &&u e m n.O A & i O

2. 8 3

F 4 1 a j ,...,6 i j ,. ' :' ;..... \\ ':7 ? n C O--..~..'..............'.,.......,!.....,,,4....,,.j,,.,..,L,,,,.., .* ? i -l i !o I me o : 2 < j i i-. F - 1 ~l vi. : i vi,. i i .~ t 4..

l

.s g g- =2< i i j i g I i I 1 =*: =g, , e! . - b. m x * <, t i a.e S, ).n'y?k-->~a~^-~p l 1 ~ I %=: / l l g. ,v 4 . /:,l *! -- i e[; i l a.* i i l 1 l 1 V e *4 l - 8

40.;.
a,...

= j i_- i j i i i i [" 'l 3 7 i > !

.::: n 2 e '

pr

_.z e i.

t a: fI i 1 i i l i i i i u u u u u tu =.: km As is.s =.s

u TIM I Chr)
    • n.

e< 25 a. e<n' en

4. " j l

l I l l l. *1 Il (1 \\4.0.W!W A I t i

s. 2 =.

f .4 A w*. lH} > I <<s ~ ru~ y~ eL.,,a. A vp. T ** ; p#n pupgm i i y1,' n in i l h,l g*9 g I gs i I mf -8 _'W.Y.,:,,,% s v'a m ~, . ta u N.w%. -... - - _<- -- r, a.% gel a i i. i g

w. --..

s

k. e S w*,

e.=. --- :_m -

g.,

a

    • .. ~. *.. ~.. -.. v.

2, g g g l- ,,l, iI1 i <; * :g as , x.1.

a. g j-

,=:. j e 1 i i ' %.p*.M; 'PP!2 CC AP g

  • h :e $(..,ly '..

l l q._ 3" S' 's.s 2.s b u u

.s u.s Rs ma ts.:

=.s

(s TIMI Chr)

...W e a e %, e

  • f.d

~

g. ,. w.a - 52H F2MAAP 3 N. i t 1 E-c :~ ~ -:1 ree ..! i; ' f J al., s.. K. i .a .,s ~ d[_* .i 1 .;. ]

  • 3_

a. '"~ ~ n ; j.a..c.>. J.?. r.n.w.. ~ - +s:;+:=- D u. w,:u. ww p., w L w as a. C*' A _s w3 m' \\ a. i 5 1 3- - - x; \\w 1 ~ . 'u u u u 1.0 u 1.s u k h TIME Chr) I

s

,3,, a. l t. g. / p , c,=. a ./ d a< pf. ./ *,; -s e w a*' / 4 w.{' ( 4 ,/ ,.4 m -. E g*- g l \\ s s V ,e -.m v.< wi< a l 3 w ' e m, s.. 7 g l l / I. i l I,. / 'u u u u u u u u e.a a.s TIME Chr) u. e l I - -... C. ' '~t..,. \\

w_ .c. _..,> ..s. 9.' , 5. t i s s. 7....................... -......f....._i .... t t,, i .j v:, ,~; = i. w.,. m2.....__......__......y....___.s..._..........t._.._._....-....t . ~ j QM i w v.. ...i .,. g 4 _ _.. __._ _.7 j._. i m g,_3 o w. m., ./ t 3: a y.-.

t.. s ee

=1.J. < m. cg e'..... l,. . f.' 2*.. O m l:* e. ey _._:::.,,.___.5 53- .__._...._2. 4< i i w { l u e., i i - s, _ _. a i. i., i 21 !__....l .I :._. i i

e.. -

- a. r, g. a.a a.s a u u u x.s u a a T!M 3 Chr) w 2 .2 .j i i. i i. 1 i i l l i.,, ,e ,o d, # "j l l i I e d.j i l l l. _. og a, / gw w l / aO: f,*q va, \\;

r. 3. -

= -N.. ,\\ <s, 16 a w f 3 a m. ,i a m. g' '. w_ s c ,4 ,I ' 3 II i w.. .t ,a r e. ,o t. , <T.. __,2. l \\.. h. l l s= a g o.o u u u

.s u

u u a u e TIME Chr) i RB .I.. c.1 8 e . + - * * ..s i ,,r... W.

.-.-- x-

tip ta;-

i.

CAVITY CONC PEN DEPTH He) CAVITY WA1Et MA45 (llem) eld ese een es. en en en en en om en se is se se 4e se se re se se g. g-s, n. .n. g ._ g _-_- ~ g g. ~ .) _.u y,4.. = m g g. e g _g_ g. t l. g g. i. m g . -g_. o, g g g -a .o. -s a. E n =g _g m g. JF.. 3-t, _.g p i 9 i 9 c,r; .,c ) i E _g _ b. 5:~-M i i t[ giD i s a l E w a= = u } g l_ p - h. C jr .l..

c..

p3 c - i. n i f. c :- E p h (C3 ) b.. c_ j l gw e+ I l ti i : l.. r4 i 6 I. u =. y h-neee e se sees.e seee s asse.e.ses e seese seese rease a se se is se se le s ne is e .... CAVif Y COtlWM TEMF ('F) ... LOWER COMP WATER LEVEL He) .e

.-e-. .. = ~ /.**.. = - n ,.a..=8 / j i v. N ^ i /,( ! w l t W 8 f 6 '% ~% N.......~... s t.iw 74 3 . j i . s., y a o D Te .r nl i i I I e Ip i .a 1 a u r sv a s !..2+ a. < t,. 9-E V- ~. { O .w", -M , i J v atw a -y. O. 1 i t g . 'u * :.s 4.s 4.s u m.e =.s u.s ao e:

n.:

=. :

4.s TIME Chr)
  • o
  • 9v TO n.

1 n- -. 3. \\ l l l l l l i M2' .3 i O.l, l 0 17 n. m..- l <=, i ( we: l =2 w", i 4 l m., y.* l \\l i "7 u 4.s u u to.s uo as u.a ao zu =.2

O TIME (hr)

A b W ..m m M

i ..=- S2H F2MAAP 2 l i 4 i n. a' i o i'* i .- N.......... .J,......*..............i .n,.*.* a' ..:.-..........J.. r , n c o.., 3

e e

l aE. i. a.- C. i @ps[ifM[@kISp! .I. g y y jdubujaW" # ~ W. l 1 I i =2' ce =' t 8 I ~ 51 = i...<.+.d.e-:9'^4 - (,<< h ),i hh{ d.bY '. s. I

  • I<

.s.i , LOWER ccMP

a.. ;

nj l 1 Es: gg i O ( j - -

f. " '

jl { i i 7 l l 1 i i i

I

'a ~ -l j p', smau.nusuun, i i 8 i 8 S, ~ f; e i e ,k".. _ _ l i i i l i i i i I 's a 2.s (s b u na 2:.o s.o As is.o 20.0 22.0 2'As TIME Chr) .':2 3, a tt News: ' comp L l S 11 iffil -e d '= i l p

== 1 43 u coa

  1. 9 Pt bum l

M ."9M l %Qg i gM

  • Mr.'E9% h _.mm-d g-w-

-,r~......y, 4 ^ *- w e' We'(: ,.*e . ~e 4g' , 'j '! !, i LPPit CIDMP [I., n. i-O* \\f1u4 i i n %I S: e 4 3- ~ S' u s.s 4a u a,e as as s.o we te.s 2a.o =.0 240 TIME Chr)

n.

a a ..9.*.

  • =
s., r i o ^

pr,.~ Oe -e i a. i. ~ = .= OO. C. e- -g.

3... e.

(

  • e._i 2

e mw l........

  • i, t.

n 1 r----% t mo a N [!, O I f. s 2 s i. i a 1

o. '

u u La i: u i.: u a.o iJ TIM E <h.-) . e i = ~ < ,i ( , fi o te l CI e / !! ro i 3.. -= s / di .~ 2 J / / ti ).* gm e m / f m ,/ s. 4 q e m . rg, ,. e i. -w% c 4 a s O m e v ee. l' ,e gg l a< m m ,/ m e. '. = f e a. =. a. - l a o e., s. i / l CA CJ L3 LS 1.2

  • J 1.3 SJ 4.0 4J TIMi! Chr) e l

j se l ~%_yy y__. _-w, p ._..%-p ,_.we-,.;

s u:- u> 'w i e 1 MASS OF IHTACT CORE @d

  • l0*

TOTAL 112 MASS GEllERATED IN CORE (llam) I se se e in n i< e us one see sa a sie se e see so we ice e ise e see s ass e wee noe 4ee s ..m C. n .. ) ...i-h l e g I s t g-g- t, I g. g. _ t. t .a ae Q m .a ~ e 1. aPj l g - -{ y j - f-W K N ll s ~ ~ N 't i / ) N 11 m m OJ / p t a: p ".e. Su / d. cO gp <=p) / =3 / g .v ' g

.7:- h-::- {cg:y:.

a..

p.;

c : - e

c..
g. 3 l

t.a

car,

/ c -r g. _s g. g. .s v;f c ~! 9 v e c -n l ti l .V <h ', -e p g. y. .. g p-a i

r..

3 i.... ,...........w.., .-g .-g i. 4 .w..e sua we.e aw.e ue.. n..e me.e ewa we.. sw.e se =e ne n. 25 a ae ~ i ... UPPER PLENUM TEMP ('F) ... REACTOR VSL WATER LEV '(fi) I f

~ e w_._., ._s.. ,e.,.%.,. .h,,,,., %e. o - ;=., i. ,............-...----.....a..............-.------., i ...~ ~ t.,. e t .o, n,. a I F-t i 2 f w 1, -.=: a = I e.P 1 1 m o, ..a M ti 4 *'. . '8 f , t-l 6,, \\ a l m 4 l I l .o 3:. -, v s u m I b n. n o t,,.I. ll i v -..'n t t i. 3,l 1 r, .\\ 3 i .r i to I .= t i 'c.s u u u u u.o su iu =.: =.s

b lA C,ne) e

.6 e,i o ,=.*% pp 13 r A*:- ,~ r l ,a n 1 . e.u n - e., o

4.,

..,t *. / m ,i 6J si / .o. E ei ~-.' t / .. = _ = _ n -...~i l w u ,3 o c-i ~--~ +-- -....... . :q v y ; j. ,f i. l I i O ,s '. V .g >< l l a v

3..
' ! I

'. 3 l ,a u c. . i. l i ...........i 1 l y. I . s, i .c.:

.s e

u u is.s w.m tu tu

n.:

=.s

u TIM!! Chr)

, t!!' p... - -e +.. k

q,*,;"t G e ',---

\\. .S2HF F3MAAP 4 + h i i 3-y I l I 4 e.g l o l

  • s e '
  • w as e-e-
      • S O

.. e.. .O, v ) 6- \\- \\. - Q' '.\\. )

    • gCg * \\ '

g., l j w 32 ,s ..,,,,, y,, y '\\j\\ J,.1 o 'A, 0 w s a W j y,- s. c ...y*. (S[e e ,.g... v. p y.m a.N.,.tliiA7,...

s #~

. l. l 6+ x... a u

.s

.o os is is.s sa na is as so.a 2Lo 24.s TIME Chr)- 1 i!' . a,

  • h 2,

, \\ ~ .; \\ 1 a.; p e, g=, \\ ~\\ IEe- \\. s< 4 \\ s e i h 4 w ** : l W1 l t. 1 w I 4 l t j al I \\, s e' [ a.s. s.s e as a.o st.s as na as me so.a

s.o 24.s TIM E (br) ist g #
  1. 4B 7

- h

  • E

[ _ _, - -- -.. - _ _~ _-___ _ _ __- _ _

. ~ _4 a. ".'. i_ .y e-s s .-~8 e & O *S $ S Q A d a n ;*=' A a .o iwe C o rg M 1 e I ? o - o

c. e e,

i j ,e a

'*" * "***,. * - - - = =

e =y 9 e, r-* ~~.~~p.... t ~ 1 '. >',2-i - r e. 4 t. .e1

l 4-s-

O e, - ?- 2,, I. i l o 3 .4'.n - t .i ) ~~ M.j j = l'. I i 11 ot m

j 1

i %.4 i j .I { 4 t =S m 2~ e 3 i d, N c ~,.u.' w. i m

C e

t N..E.I._. F N, M d S !. k.

p. A, y

,I \\: s-i ,/ ,3 ..,.. ~ r....:...........:,.

~

1 s s,,,- -. . ~. ~. - j i. <=3 l[d l i-* *51-M+\\ c-i 4: U,w., b.~ C w r' 2 t t E 3,

%.A -

t- .O f

  • 3 M

M M La 1C.2 "3 u.: u: .u TIME Chr) eo O. 4 . CZ 6HD l .j l. a e e t__e, NL. y l s u .,. -4 Y 5 J i I A ....,1 e.I A -...#.....---...:...i l tr p t_f (',y -- - - - u,, y, i' 1 g, /;, $. '.p *;?9 # *=.lh p { } i

e.,,, j i

l. 1 1,............. i ,/ j j w .- e. l w,, l1 I r i .4 w.n ,o . w v .: j l eq a < 7 C*- o j,.*" l w-, w =< l <a I U < =,t. s 9 ll

c. 2..

q-< e.j, g r4.. g. C.- y, *,* g a I o. 1 a=< 4 C.: e u a.o m.0 1:.8 w.s tu tu

o.:
u IIM E (hr)

,1.*, 1 1 . ~.... o

\\. n== c.L-:. TMLB' F4MAAP I E i .) = 5 /: t}** l .y + ~I

. -, -r -

g..t. 1 g .2.. .r3, n5,,,., y(.e.. l br..bla... b u..s.. i e,, u.. gi t ,g. w

a. 3,

=.- = 1. g.;. . J.eg;;p. A c-V.-N "l - ".. : a s."~l www-- >w a l l l 1 i. I l c. . 'u u d u u u u u a a TIME Chr) , *o t .s. a I 4 i i g. ,/,f -= f: 1 i / 't i ..s -s

  • et.

i I: t ~=. l. .w 4*. .l .'. I s..: g -s w =* : l l l e

  • g i.

i. }- W ..a 5. -l = 3, :. -= o es3 f 'W O i v *. : w3 _i, l t .. >w -w ME: i I i i [- ! ! I i 3 I. 1 i i i }/ I. i i a. =. n. i,,. L' I: ti i.+ 3 l w. 'u u i.e b u u u u 4e u T1ME the) .m. 4r* C.1-17 3.y ~

8

  • -J.y pg

,'e-*G e o e '~ /4 L 5 ', WA A A.3 ~ O O S S NJ j ,i. 7 8(* i. i. b i M3 g 9 t y, t. s. -o i ~ e w g y 9 ? 1 W e w,g,,.3._.. p

i. :

7 gg /*' M + g l' y e I u 1; o e _., b':. o e 8 a e = g ---- i -a 1 l** m l 4,. t w a. i. s. n 4,. fi i 'oa em " ' l w i uo. I. y-i cs ~f. (la bs N < 5t 6%4 C i t,,...* - ,u v, .e - av u,.. _ _ _,, 'i o <o, <0j i

  • g w

i E $4 4 t Ng t =e -.f-

=

-= I f3 l -= ~, I e. pg 1 %,e O t P= t t q i g '* ' O, U bO O $.0 S.#.

  • Q 2S 43 4.$

TL%E Chr) ya .o* O en es. q M f t I e 4 ft et

  1. t

>O e-1 i i j t et o e

  • c 89 __

i. t t t 8 9 1 I. i t a t i t i g .a-1 l ..r* i

r.. e 1,

1 W, w i. n I ,r

== o v i I .a g..............-..s..,- ". w. a i I .-g W be i. . = j g c c -a a I =w = u. i a. oa-i. t _u, f-v, o i f -o w$ i I ) 4-s o, N__ I i La l- *,..... -........... i. a i r n o.: u La i.s 2.s . u

s 4.o 4.s TL%3 Chr)

C.1-18 _ = -.

3 1 --a_.,,. TMLS' F4MAAP .c,. -g z.. i.....;...........4......-;..---..., d i y -,-,,,,..__....A, - _- i. , i. ,a i i l} ,i -g En i w .a = l s i a 1 ~ ~. 3 W9 8 4 w W1,.,. (.,1 1 l i 4 <g p Mi j j. ..y m.. .i i l 1 i a. w. n. .4 l 0 V 3., y' t = l i -a 3 i... - o vs ,4,. '\\ ra ., = i t. .i I i 2'.o c.o

.o a

u u m.o

2.0 34.s m.o to 2c.o

=.o d TIME Chr.' .3 a l i 3 i l l 1 i i 1 i i i ! / 'g a [ ,e e e e i i i m g 8 l r ' cy *** 3 ! I I I 4 i /i i ' g 2. t =". I.:. 1 / i I .34 l-,/ l l e w I 1 i. ,'..i.- w ,l l '----.... _ _ ! j--. I 'g{ C.- i-- .+... 2..,,-----!---...==: ,/ = i 3 = t i i o m. i i i i '.V / y i i 3 o~ 11 l i .2= t U lI j i I i. i i i i ..v 1 a. w: .r. l l I .!g v I i i i i

i..
  • ----- ' l I.

j j i v i i i i l / i i l i i 1 [ i i 1 .u 2.s e u u m.o n.o u.o a.o ma

c.o

=.o 04.o TIME Chr) 't .t 1. i C.1-19

== T._a .i. - c.. 3 = o , m an s..s O o ~ l .s. / ..../.....'. oe. M l t 1, m 3 i

o

+ 'l;. o .a t w I w c4 C. o '~ N: ;.., S S-s. g . v O o i -. t .i. -, - s. i e v i-1 .; 4 ue n , a t. v M*~1 4o .N r s >a t 4 O j t a , n ,b p i \\ h ll ~ - ** . i :~... l e _ ;.- n............ - ~- r V 4 a l f iN: g J. u o, c.c

.s 4.0 o

u-10.3

.s u

14.0 t2.s

.o
.3
(:

TIME Chr) % o ~w =n 1 "j i j i I s 3 i i i l I t e: i e + 1 i i 1 i i i j eel i i i + i -.3 = 1 a g i N o 4 i i n j Zol 1 i -s -c wa, CC 3 y -.-=. l w

  • a. -

t G a o< .v- } i .~ + o,4 ~ o I I I ~ n 4 I 1 6 j t u i t 7 ,s o' o 'c.c 4.c 4.o u s is tu

u

=.: 24.: i TIME (br) ) x... g.go C.1-20

) a Firt.: s C.L-5 TML3' NMAAP 3 I '.2. e. e 2 --'I i o ~o a, E, i a =a. l g l l _j

G COND

..G-1 M2, i ei - i I' 4.' i ' 8 ! PPER 'CCAP i ( [ l l 1 i i U S ]i , y i i 3 i [ !,.**'.ij,,' j',. . I =.,; m w. g u i. i,,, I. ','. I tif. i E '<.. i i fEl C*j [+Mj l/J.cw!I COMP i, i g 1 i i i i '. v3 c i { p[' i. j ); i% A _ I [3/Qb. -Q,wvI-d( - l NV" i i i e i .!JPPER RONUM j Ji i I i [ ,/l e. t/ Ir 's.o

.s a

U s.s s.o n.o w.o n.o u.c =c.o

u
k.c TIME Che) e.

it E2. l l [ l i l 8 i i I i i .i i i i i j E' i i i i l i i e i girPPER PuNumi J-I l' 1 l i 8 E. ' I i i l E l ua A. i j I: l I m 1 <e< l i l Og. I' i -E i l l 1 i I l = I j i i w i i i 3 l l 1 I l 3 4 I i i i > =. ar II. i !i i I i 4 I i j O i j / c C=io U.< t 3 [owm-cc.gf

t..:h(, k..

4.......--.4----}-l[.. .} i PP5R COMP l i i i 's,o u 4.s to a.s so.o n.s ks u u =c.: =.o

d TIME Chr)

.8 C.1-21

we-i i, L.4 4 lfw: (~ C,3,n, %n.* oo O 3) i a a, ac....... "l / 1 ps. / L,( re_ ?'d l o<N i 4 t, . -. -e - ' ;;. - o gg--

, c.

-s S c, "d o LiC. E - S-c w ...,..n.~.. : p. '-~ m O. g u_ o_ g. ~. 4 C 4 oI n O u u u b

.s 1:
.s a

c TieWE Chr) o

e. =

a o .:s

n..

I I .i L =. i Ag 1 t o, i i o. n; I d C.3, -1 ,'l1 a. i 1 e. I o 6 4 a i ll ~ 3 i i Los ' l f r 1;

  • ao, i

m de

  • ll m

l -= co. 1 /q, o. .o...

  • C

-o = 4 g Q e,. a i i I, L,'

E w.

o. o ..j y j l om <n C v DOJ ( Ei a Cj m Y-s . o >. e' o. .,m L/% O i 4 >. ~, i .ar I l / t a". i + r o 1 n ,o aa-c g;. t ') -w ol i ,' l s e o, o. o j o. a. t .n a g a o. 6 i 4 I i o. .o o. I i g o u w d La u u u - a a TIME Che) w. .N C e e ,B e e= W >ew +-+ e us. .. m-w -ev ger-a w

  • e pw-w e,

, ppe.wwen.s

    • -e-

3. \\,,.. 723ML F5MAAP 8 = w. r. n. c 'o w*< i i = m=

. =~

O"' l v. OC w a. a

o a

. g 1 s l c 1 .- i -2 i l [ w.- m w-I y W ,._ ~4 <a j i a-m .e r . a 3; w l p: =.<.. w.. 2 .N CA. i / i .l l. _o= i a. . t. ',, a m m.. .o T=. i .= =g m a-< f -2 i [ j

  • o' 3

o o g, { l i. o c.o c.s 1.s u 2.s u 2.c u .s.o d.s ilM5 Chr) a. j f l l\\ ./i. i

k. *,*.,

i I a i l l a 3 l I i 1 a . -?,. - a 5 i -- o a. t w.< I I W$ W I. l l t 88 s l l I O 8( ,', =

  • V s

..w i = n e v., .

  • a.

w s w -O g o 6 ~ 3 8 8 I I - *w Ce' l j i t l ,.a u 2 6 m .i i e. 7%. m i 4 ( s s t o G' = ~ l

  • I i

.e t ,e ) o e-t S $.8 E.M M d(.O IIM E Chr) r.e. W C.1-23 N 4um

- __., g /, .. en -,. - \\ .. 2 i-4 l l_ r3- / *. A,..) tpw/ % a. o E t' s..*.*, o

  • .r

.......... O i r-f: e .t F w ? a. f e e. 1. .e o 4 f e,. m = s.. i ,...,......r l sa ~aw -..! n + + s - L; vn a t g. j "~"?~g..~b* ~. u (o4 u e e .eg o. e w, l IeC . :a.. i. I* V 1 o ( p.,.,-- ..t .e; .e w.~ t r 1 O :o. e,. t e e [', v %o t y c, e l t a [ I 4 to i

  • c t

i s

o. 1

~ ~ n' ,6 i o. [ . o o

  • o 2.3 Le 2.0 3.3 4.0 S.0 6.*

7.0 9. I".3 C %.% t* / 66 e e .e o n o . ~ a4 C s 9 g . C.a g l e I I E' I f l 5 6 ) .o = w o. i c. c v ' l y "t, l t ' o. V i l i a O a. ' _o2 i ? . n" - vo - g i . *v a. . a i -g v ;;; 6, .....s..................(o t l. 1 4 -=

  • ..t....................../

i i 4 .j l = I 1 1 o 3 o .e o.c to

.o
Ls

..4.2 S.s 6. 7.2 t.o e.s i:.: TIM E Che) .N..k. C.1-24 _ _.,.... -.. _ _ _ ~

, :s.

_,,._..--.2-

.T23ML.:5M A AP i.l i o. i ~ 'i ^ i TE I .a. J =-- ~ m m n ya* ,( a G. (k 8 m-' l ', -a v.- 1I

  • /

l 's ._i f O 1 ) N 1 = . y :1 w

3. :

O2 4 i +

o..

il .; 7 i j i s 1 I i I a.c d to La a s.a Lo 7.c n.o s.o ic.c TIME Chr) .n 3._. ~r ~*": 1 i i j i i iT i. i i. i i l g a. i l i: g I i 3 \\ l I i -.1 \\ I i s. d- [ l c : '. r 8 l i 2 I 1 i. g =- 2 ".. j j [ j m i I i I.. i

  • 2,

.i i j viQ.: I \\ i i { I i ( j i i 8 I uJ. l l v a. I l i I i I, g i N i i \\ t n l i 8 s i o.0 W La LO S.0 U 7.0 8.3 9.0 W TIME Chr) I" C.1-25 t l

r, - ~#-...==. "..2, ir. .-g e P r, 'e s

    • O Q 1A I C%&A A

a

  • i

%, / 7 \\ L a e / f '. (". /%.* O C

?. j l' '

'=...:.........;s****** K*-~~~~~=?-=== *-~.-=~== =^*'.==~*' s 3 1 i o} + e a. e,; s. 3 =_ =. =. - .g p w.. A :w e -4 l.' 5 9 el O.c.1

l..

r. g b e. ~ ~,; - j u c.'! _ _ _ _ _ 4. wa %, O, m t i 2 "'". o ' i a' a t No- .I

== l i:..v- ' r.. % ~ ; i.-'...;;u, Q :_:::.m. i - . + ~

== 8

== a keg se . g N j I ! t + w. N ag,f c.e o 3 I t . e g-. g,6 . M.uP*g =I ? F***I,, a A % -a. 4 6 asi i_ ett i .t p e. .s il.; W %P i ,1, 7 /* ".-.s*

c. 4 i

/ ij ' --- - "- V e 3.~ /) mfr:1 r.3 M w /6. r e l 5, i- .4. ,' j. i l o $.0 3 $.0 b$ d E.E d e.0 8.3 T.3 IOS .ua r*M Js $ 1tnC o. e

  • 2

-tot O M g e a 3 I. ,i 4 h o. [ e. i c. e e M j. d4 h. 1 6 .=.0< i e W ND LW E. l 6 i i t t t/5 d<*- i i. WE Sm i I y ! "7 Pelt 7 LINUM N / We. a MO 3 1 ($

d. - '

e. e N' O V ) e. C E C._ m t j j I j CWII COME '7P!2 C O X P /;I CON ;; y-- r a. ..J---=----------.----------------~~~~~--- o, e".$ e.E M I.O I.O T.) '0.0 6 hhg. g. )

v..

b C.1-25

3 s Fip: e C.62 AD F6MAAP n ud "b$h/Ak j -6 j o /\\ %,w.A y I. =. ' n --.3.%.... N W'N 1" j j 'N k i i m i w=' 'l

e. n -,

as 1 db h=' \\]. + v= .I s as i w j i c..!.- 3.- l l i O m' a I-I-- i i i i i

e. '

'o.c

.s lo 6.o a.s tc.o c.s u.o u

m.s

.3
.s 24.3 TIME Chr) b,,,, ~*

e n. l i M, -i ) i i i a ~ f I a.. I I i i E *.. aa j g a 3 e., l l i l i i 03-I i I' = l 8

E:.

St <2, I m., an s. g a g f. t#9 I l 1 i ( U i i i l j w.: 1 i. i i. M' i l i I w { 3 I I i i 8 g 8 I { I I i f I 8,8 2.4 4.9 6.0 &,4 30.$ M k2 M M S0.0 D I40 TIME Chr) '.b.Y.

[ ,n ~ s=. V i' C in n, n,.* c e. c.1 .c aj . ;....... g...'.............. ........,....,,,,..,,.... 4....,,....,,,,,,,,, l - g.. 3. ~;

  • 4 v.p s =.ss.. :

...p;%..p. - - - - - = - e t i i

oi e
3 e,.'.

.a a.. _1 m m al <e-4 ~ .*, o <'. s b. f I t s o< _.4 n -j -i -,,, ;.j H + L w-j s.I .r i g n. u1 I a e --C 4

  • m,./ O s

> 1...o. -ag

- n.

"ya.1 :.:... v.--- c

! (G

-L-y e I' 4 _= ....,a n s n. l' # V _I e.1. ?. 6 + ~ ..c...... A "i ,r. ~e C )4 1 s o

4..,

In.,. c 4.. L. 1#.4 sar) e .i.e a n< l I e< e< 1 i va. - i "i j oli.o. oi 3 i ,,. a - s +

u. n i t ;. l i I

+ ). .I ~, o 4 (*I I ,. o - .../:- .-r:e p2 i i

  • 4 I

/ [ ua

  • 4 h J!i\\

i i c --_.i.. ' h7.',"==.- %.-(..a ,#.:.., s..n to.. I --.:-. - r. e#j i' 4 r 2 i; .f"!,' $.(C'7V--ND,G'&...TQR%..<g_.,d. :..,..7.. eo.a-i i > = *

  • f f

t [,,,,,,,,,,,,,,,t.,,, yCgo4 e 9,, .........,<.....,.m,. E 8.s I e t ,,,V e .: -+. 0 p,;,.; * '. 'k r'R e ;.- _f< v wwM-e .u.,.w. r t r s 4, t I O.,

==. M 4 t ) e. a. I 1 [ s 9 Q M 4.,$ d M M b* b SM e.= r T'f,Q ('ne) ne.n !.W C.1-25

Ti.g:.:c :.5 '- '... ~. ' AD F6MAAP l .e i. t + .o a. 4 1 - = s g s W 1. y U Ep L -_

  • =z:_

} j i i .a m w I = i. a. i a.., t. I s -w.,-w-:. x.tt a.. . v4.!;,;. 9..r....., _,.i. m.. s -... ~. en o 2,1 i t -= t a. .i i = a it s N ~ 'u u La u

n
.s 6
.5 o

O TIME Chr)

=,

= e, l / l i i l l I E, i i ? i .. = i

j e

u I j M i [ g i. i. i. r w e s.g. i (a< l l l ..g -s i = e l g m -, 3 - i '.E ( .= -o Ee .e [ U aa w, O I m v i g -.m M. o as w, i a. l I E I l s. i l t l l i a, j l -o I s e I e e i e s g 6. f. .'8 0 M 0.0 W W W

.8 U

M M d d TIM E Chr) C.1-29 m

sr. ...., o - ,. N.- .% A,A 'A <h.,i..O !N v O a -g ( I .... [ a .. a.........y-f e w - a t .i,. ..u o, .s 4 / I 7. c ; J. ya< C ae t. ',I au e

  • i ng
  • .- O j o,

J ,C"- D-8 e P= n, e <u.. a. oa e -. - c y> 5a. 1 1 w0 i ~ u .s a G o. i p=,

g f.

i j 1 e s. e, o. a i ( .-.= 4 6 i To a -o - o OR; i r y I l a j t 1 l l i i t' lai a o i 'e.: s 1.s i.s

.s u

(a .5 -. u.. - s.t ) s. o. o go o o ,,c. ,e, I I l l I 1 o i. e l i

..~...................,,....u~:_

[ s. o- { e. n ( o."' I ". ~ 3 .m. - L, .a, e s

      • e
  • c.

s ee o UJ a, L.W r L p= A O %n* . e O*c *: Q o 1' s p em. p ef b 11 " k "6 UC7 4 <=n.,, o --a a

  • l F. o c-

>= H / } ng O );a e i w l u. I.

  • o=

O o,' : -e

  • F UT

, 8' = } W s 4 e

o

. l i a. i ,.e } } i. ro ,e o. - i. t N l fI ge < : l '... i. \\I

r. a-

?.., } i' - o "O >,o s a e. IIM E (hr) /

m....

It* C.1-30 ..g.e+ pe n=ww .m...Ow= ee--q*..4 =

.u.: s _) D . AD F6M AA? e. T* g + g ..s g H.. / i i 1 = p . = = U i + i i U i.* i 5 A d l e,.... g o> ?.I' -s "' .a c.< W g e i 8 i w i e i 1 i l E: ,- 3 = I i m e.. i 4 '.o 3 i I ~*U y.:: -r .5 1 i "t i l < I .. o. U.4 i i i s i l -a y.o c.s

.o 4.o U

U to.o =.o 14.c ta.o ts.o 20.o =.:

d TIME Chr)

.E l l 1 l l i i i .z < i l l .2 l.,i l 1 i jl i. l 1 i. I i e 2 0.. i , t e. ,w j I - = = < l l l .44 m le, l I >= w .S I I l l i C _ s. g3 ~ . n as = s. o 1 a. V 3 U S. ' 1 i l l . :t t-o .o> l v

t i

3.3 < et I' I 5 ..v i i 1 ;; l l i l - g-g v *., i i ;... _... I ... I.. I- -....i.......i. . i..... _!...... !..... f

  • I I

I i l i e i i 1 I i l f* g< I i i 4 i i i, l l i 2.: i t i. i 2 a.a in d b a.s ts.m is.: 54.s tu ts.o =.: ri. TIME Che) m,. C.1-31 -,-,_w. ,-,s ,u-

6 e Directory to Documents on the Severe Accident Source Term Reassessment June 1984 NOTE: The Directory will be updated. Christopher P. Ryder l I l l l Hf

c-f. .s Foreword The Directory to Documents on the Severe Accident Source Tern Reassessment is a listing of documents that are pertinent to review the source term reassessment. All documents in the listing are available but all documents have been distributed. The most relevant documents are distributed. Documents of secondary importance are kept on file at the NRC or at the APS Studf Group. Should documents be need, call either the NRC or the APS Study Group at: NRC: (301) 427-4337, Christopher Ryder, Technical Assistant, Accident Source Term Program Office. APS Study Group: (617) 495-3387, Kamal Araj, Executive Assistant, American Physical Society Group.

r. LI' Introduction The Directory shows where the major topics in the source term reassessment are discussed. In the Directory are the following sections: l (1) Matrix -- The BMI-2104 reports, the supplemental reports, and the IDCOR reports are tabulated along with the major topic in the sou'ce ' term reassessment. The report titles were abbreviated for the matrix; the full titles are listed in Attachment B. (2) Transcript Listing -- The major agenda subjects of the Peer Review Meetings are listed. The transcripts could not be directly indexed because of the loose structure of a spoken discussion. (3) Attachment A -- The topics appearing on the Matrix are defined. (4) Attachment B -- The full titles of the documents appearing on the Matrix are listed. (5) Attachment C -- The documents discussing background information are listed. J e 2 J

p Matrix: page 1. BMI-2104 Radionuclide Release Under Specific LWR Accident Conditions TOPIC Plant Fission Thermal Failure Fission lhermal Selection Core In-Vessel Product Hydraulics of the Ex-Vessel Suppres-Product Hydraulics Sequence Melting Core Behavior in the Reactor Core sion Ice Behavior - in the External DOCUMENT Selection Pnenomena Interactions in the RCS RCS Vessel Interactions Pool Condenser Containment Containment Systems Vol. 1 Ch. 3,4. Cn. 5. Ch. 5,6, Ch. 5,6,7. Ch. 5.6. Ch. 5,6. Not Not Ch. 5,6,7. Ch. 5.6.7. PWR Large Dry Appn. B. Appn. A Appn. C appli-appil-Containment cable cable (Surry) Vol. 2 Ch. 3.4. Ch. 5. Ch. 5,6,7. Ch. 5,6,7. Ch. 5,6,7. Ch. 6,7. Ch. 4,5, Not Ch. 5,6,7. Ch. 5,6,7. Ch. 6,7. BWR Mark I 6,7. app 11-Appn. A Design Appn. B cable (Peach Botton) Vol. 3 Ch. 3.4. Ch. 6,7. Ch. 6,7. Ch. 6,7. Ch.4,6,7. Not Ch. 6,7. Ch. 6. BWR Mark 111 Appli-Design cable (Grand Gulf) Vol. 4 Ch. 3.4. Ch. 6. Ch. 6. Ch. 6.. Not Ch. 4,6. Ch. 6. Ch. 6. PWR Ice App 11-Condenser cable (Sequoyah) Vol. 5 Ch. 3,4. Ch. 6. Ch. 6. Ch 6. Not Not Ch. 6. Ch. 6. (Surry, Appli-Appli-recalculated) cable cable Vol. 6 Ch. 3,4. Ch. 6. Ch. 6. Ch. 6. Not Not Ch. 6. Ch. 6. PWR Large Dry Appli-Appli-Containment cable cable (Zion) Code Validation The report is a review of the modelling and the computer codes in the BMI-2104 analyses. QUEST The report is a study of the uncertainty in the computer cades in the BMI-2104 analyses. Notes: (1) See Attachment A for a definition of each topic. (2) See Attachment B for a 11st of the complete titles of the documents.

s Matria: page 5. IDCOR Program Reports (Continued) Fission Thermal Fission Thermal Failure Product Hydraulics Selection Core In-Vessel Product Hydraulics of the Ex-Vessel Suppres-Plant Sequence Melting Core Behavior in the Reactor Core sion Ice Behavior - in the External Selection Phenomena Interactions in the RCS RCS Vessel Interactions Pool Condenser Containment Containment Systems Report 16.1 Ch. 15.1 Ch. 11.1, Ch. 11.3 Ch. 14.1 Ch. 15.2 Ch. 14.1 Ch. 14.1 Ch. 11.4 Ch. 12.2, 12.3, 14.1. Ch. 15.3 12.1 Assess Available The scope of the code, The phenomena of a severe accident are not discussed. i fly Codes the structure of the code, the solution techniques of the code, features of the code, and an uncertainty analysis are br e The report is a user's manual for the MAAP code. Report 16.2-3 Disccussed in detail are the input decks, the batch output, and file index, and a parameter file. MAAP Vol. I discussed. The analytical methods used to model the phenomena of a severe accident are The analytical methods are divided into subroutines; a subroutine or group of subroutines makes a quantitative The report is a user's manual for the MAAP code. Report This report describes the subroutines and how the phenomena are modelled. 16.2-3 discussed. estimate of some portion of a severe accident. MAAP Vol. 2 Severe accident phenomena are not discussed. The report shows flow charts of Subtask The report is a description of the HAAP code. 16.1 the MAAP code. Review of the MAAP Code This report discusses the analysis of the thermal hydraulic and radiological response of the primary system and t IDCOR at the Sequoyah Nuclear Generating Station. lASK-23.1 (1) See Attachment A for a definition of each topic. Notes: (2) See Attachment B for a list of the complete titles of the documents.

I b ~ Attachment B Volume 1--Executive Summary (unpublished) Full Titles of the Documents Listed on the Matrix Volume 2--Analyses DMI-2104 Reports "Radionuclide Release Under Specific LWR Accident Conditions" BMI-2104 series. Battelle Columbus Laboratory Volume I -- PWR-Large, Dry Containment (Surry) Draft July 1983 Volume II.-- BWR, Mark I Design (Peach Botton) Volume III -- BWR, Mark III Design (Grand Gulf) -Volume IV -- PWR, Ice Condenser (Sequoyah) Volume V -- PWR-Large, Dry Containment (Surry, recalculated) Volume VI -- PWR-Large, Dry Containment (Zion) -Supplemental Documents " Review of the Computer Models of Containment Aerosol Deposition"

5. Beal, Advisory Committee on Reactor Safeguards / Nuclear Regulatory Commission, June 1983 "A Discussion of the Concept of Deposition Velocity" (draft)

D. Power, Sandia National Laboratory NUREG/CR-2921, " Chemical I'nteractions of Tellurium Vapors With Reactor Materials"~ R.'Sallach, et. al., Sandia National Laboratory, July 1983 - NUREG/CR-3248, " Studies of Fission Product Scrubbing With Ice Compartments" U.S. Nuclear Regulatory Commission " Interim Report on Accident Sequence Likelihood Reassessment (Accident Sequence Evaluation Program)" A. M. Kolaczkowski, Sandia National Laboratory. August, 1983. " Severe Fuel Damage Test Series, Severe Fuel Damage Scoping Test, Quick [ Look Report," R. K. McCardell, et. 41. Idaho, National Engineering Laboratory, December 1982. I " Severe Fuel Damage Test 1-1 Quick Look Report," R. K. McCardell, et. g al., Idaho National Engineering Laboratory, October 1983. Review of the Status of the Validation of the Computer Codes Used in the NRC Accident Source Tern Reassessment Study (BMI-2104). T. Kress. Oak Ridge National Laboratory. l Uncertainty in Radiological Release Under Specific LWR Accident Conditions (QUEST -Quantitative Uncertainty Estimate of Source Terms). Sandia National Laboratory. IOCDR Prooran Reports Technical Report 2.1 -- Ground Rules for the IDCDR Program, April 1982. Technical Report 3.1 -- Define Initial Likely Sequences June 1982. Technical Report 3.2 -- Define Initial Likely Sequences, October 1983. Technical Report 3.3 -- Selection of Dominant Sequences - Update, Technical Report 11.1, 11.4, & 11.5 -- Estimation of Fission Product and Core Material Characteristics, October 1983. 17

i Technical Report 12.1 -- Hydrogen Generation During Severe Core Damage Sequences, June 1983. Technical Report 12.3 -- Hydrogen Combustion in Reactor Containment Buildings, Volume 1, April 1983. Technical Report 14.1A -- Key Phenomenological Models for Assessing Explosive Steam Generation Rates, June 1983. Technical Report 14.18 -- Key Phenomenological Models for Assessing Non-Explosive Steam Generation Rates, June 1983. Subtask 15.1 -- Analysis of In-Vessel Core Melt Progression; User's Manual and Modeling Details for the Fission Product Release and Transport Code (FPRAT), June 1983 Technical Report 15.1A -- In-Vessel Core Melt Progression Phenomena, July 1983. Technical Report 15.2A -- Hypothetical Core Melt Accident on a PWR Vessel with Top-Entry Instruments, June 1983. Technical Report 15.28 -- Debris Coolability, Vessel Penetration, and Debris Dispersal, August 1983. Subtask 16.1 Vol. 1 -- Review of the MAAP/PWR Code, May 1983. Technical Report 16.1 -- Assess Available Codes, Define Use, and Follow and Support Ongoing Activities, April 1983. Technical Report 16.2-3 -- MAAP Modular Accident Analysis Program, Vol.1, Technical Report 16.2-3 -- MAAP Modular Accident Analysis Program, Vol. 2 August 1983. IDCDR Task-23.1 -- Integrated Containment Analysis, June 1984. "An Assessment of Existing Data on Zirconium oxidation Under Hypothetical Accident Conditions in Light Water Reactors," L. Baker, Argonne National . Laboratory. IDCOR Program Plan WASH-1400 Executive Summary Main Report Appendix ! ----------- Accident Definition and Use of Event Tree Appendix II, Part ! -- Fault Tree Analysis Appendix II, Part 2 -- Fault Tree Analysis Appendix III --------- Failure Data Appendix IV ---------- Common Mode Failures, Bounding Techniques and Special . Techniques. Appendix V ---------- Quantitive Results of Accident Sequences Appendix VI, Part 1 -- Calculation of Reactor Accident Consequences Appendix VI, Part 2 -- Calculation of Reactor Accident Consequences Appendix VII --------- Release of Radioactivity in Reactor Accidents Appendix VIII -------- Physical Processes in Reactor Meltdown Accidents Appendix IX ---------- Safety Design Rationale for Nuclear Power Plants Appendix X ----------- Design Adequacy Appendix XI ---------- Analysis of Comments on the Draft WASH-1400 Report f 18

{ Attachment C ' Documents Discussina Background Information (1) "An Assessment of the Radiological Impact of the Windscale Reactor Fire, October 1957." NRPB-R135, Chilton, Didcot, Ocon, 0XII ORQ, November 1982 (2) "The Behavior of Iodine Species in the Windscale AGR," J. Hillary, United Kingdom Atomic Energy Authority. 18 March 1970. (3) " Final Report on the Incident at the Lucens Experimental Nuclear Power Plant." Translated from the original German report: N2C translation 1053 (4) NUREG-0771, " Regulatory Impact of Nuclear Reactor Accident Source Ters Assumptions." Appendix C. (5) SECY-83-219. " Status Report on the LWR Accident Source Term Reassessment." Note: Schedule presented in this NRC policy issue has been adjusted. (6) NUREG-0654, " Criteria, Preparation, and Evaluation of Radiological Emergency Response Plans and Preparedness in Support of Nuclear Power Plants." (7) NUREG-0396, " Planning Basis for the Development of State and Local Government Radiological Emergency Response Plans in Support of Light Water Nuclear Power Plants (8) NUREG-0900, " Nuclear Power Plant Severe Accident Research Plan," Larkins, J. T., NRC. (9) NUREG/CR-1724, " Proceedings of the CSNI Specialists Meeting on Nuclear Aerosols in Reactor Safety." (10) NUREG/CR-2299 "LMFBR Aerosol Release and Transport Program Quarterly Progress Report." Vol. 1. January - March 1981 Vol. 2. April -~ June 1981 Vol. 3. July - September 1981 Vol. 4 October - December 1981 Kress, T. S., Tobias, M. L., Adams, R. E., ORNL (11) NUREG-0544, "A Handbook of Acronyms and Initialisms." (12) " Nucle u Aerosols in Reactor Safety," June 1979 CSNI. (13) The Technoloay of Nuclear Reactor S*fety. Selected sections. Vol. 1 T. Thompson. MIT Press. (14) TID-14844, " Calculation of Distance Factors for Power and Test Reactor Sites. March 23, 1962. Division of Licensing and Regulation, AEC, Washington, DC. (15) NUREG/CR-2629, " Interim Source Tern Assumptions for Emergency Planning and Equipment Qualifications." (16) NUREG/CR-2239 " Technical Guidance for Siting Criteria Development." (17) NUREG/CR-0772, " Technical Basis for Estimating Fission Product Behavior During LWR Accidents." (18) WASH-740, " Theoretical Possibilities and Consequences of Major Accidents in Large Nuclear Power Plants." 19 L

(19) Nuclear Aerosols in Reactor Safety, CSNI. Nuclear Energy Agency Organization for Economic Co-operation and Development. June 1979. (20) " Calculation of Iodine Removal by Spray in LWRs Containment Vessel's," G. Nishio, et al. Journal of Nuclear Science and Technology. (21) " Degraded Core Accidents for the Sizewell PWR: A Sensitivity Analysis of the Radiological Consequences," G. Kelly, et. al. National Radiation Protection Board. (22) " Interim Report on Accident Sequence Likelihood Reassessment (Accident Sequence Evaluation Program (ASEP)]," A. Kolaczkowski Sandia National Laboratory. (23) NUREG/CR-0400,'"On Risk Assessment Review Group Report to the U.S. Nuclear Regulatory Commission," H. Lewis. (24) NUREG/CR-1250, "Three Mile Island: Report to the Commissioners and to the Public," M. Rogovin. Volume 1 Description of accident and conclusions Volume 2 Part 1 Licensing and regulatory background Volume 2 Part 2 Technical description of the accident Volume 2 Part 3 Description of responses by the utility, the State government, and the Federal government. (25) 10COR/NRC Meetings > Accident Phenomenology and Containment Loading - November 29-December 1, 1983. Summary and presentations. > Fission Product Release and Transport - February 7-8, 1984. Summary presentations. > Integrated Analysis of Containment loads - May 15-17, 1984. Presentations. (26) 10COR/NRC Technical Issues (27) NRC Containment Review Meeting May 30, 1984 TEC Corporation, Knoxville, TN. (28) NUREG-1037, " Containment Performance Wcrking Group; Containment Leak Rate Estimates. Fourth draft. (29) Containment Loads Working Group, papers > Meeting at Brookhaven National Laboratory, September 1983. > Meeting at Argonne National Laboratory, November 1983. > Meeting at Electric Power Research Institute, Februa y 1984. > Summaries. (30) MarvikenProject(Selectedreports) c (31) APS/hRC Meetings > December 2-3, 1983 Dak Ridge > January 16-17, 1984 Sandia March 22-24, 1984 Cambridge > May 21-22, 1984 Berkeley (32) " Glossary of Severe Accident Sequences Analyzed in the Source Tern Reassessment Study," Battelle Columbus Laboratory. (33) " Accident Sequence Progression," Battelle Caiumbus Laboratory. Sussiary. 20

a. ~ (34) New York Power Authority Source Ters Study. Nuraerical results without ' text. (35) NUREG-0772, " Technical Basis for Estimating Fission Product Behavior f during LWR Act.idents." (36) Sample of computer output. Battelle Columbus Laboratory. (37) Letters from the ASTP0 Peer Review Meetings > January 25-26, 1983. > May 24-25, 1983. > July 28-29, 1983. > October 12-13, 1983. > January 26-27, 1984 (38) NUREG/CR-3028, "A Review of the Limerick Generating Station Probabilistic Risk Assessment." (39) NUREG/CP-0027. " Proceedings of the International Meeting on Thermal Nuclear Reactor Safety," American Nuclear Society. Volume 1 Volume 2 (40) User manuals > MARCH 2 October 21, 1983 > MERGE February 10, 1984 > NAUA Mod 4 Undated > TRAP-MELT January 1979, NUGEG/CR-0632 > QUICK May 1981, NUREG/CR-2105 21}}

Retrieved from "https://kanterella.com/w/index.php?title=ML20128N237&oldid=4255858"