ML19289C794
| ML19289C794 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 01/18/1979 |
| From: | Gilleland J TENNESSEE VALLEY AUTHORITY |
| To: | Varga S Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7901240107 | |
| Download: ML19289C794 (34) | |
Text
_.
- s
'I TENNESSEE VALLEY AUTHORITY CHATTANOOGA, TENNESSEE 374o1 500C Chestnut Street Tower II JAN 181979 Director of Nuclear Reactor Regulation Attention:
Mr. S. A. Varga, Chief Light Water Reactors Branch No. 4 Division of Project Management U.S. Nuclear Regulatory Commission Washington, DC 20555
Dear Mr. Varga:
In the Matter of the Application of
)
Docket Nos. 50-327 Tennessee Valley Authority
)
50-328 During a telephone conversation on January 10, 1979, TVA agreed to provide the Containment Systems Branch and Accident Analysis Branch reviewers information to justify our request to change the technical specification for the secondary containment bypass leakage fraction from 0.10 to 0.25 L for the Sequoyah Nuclear Plant (SNP). The enclosed a
material includes a draft of a revision to Section 15.5.3 of the Final Safety Analysis Report (FSAR) and a draft of the revised technical specifications 3.6.1.2.C and table 3.6-1.
We believe this submittal fully justifies our request; and we would appreciate your notifying us of the results of your review of the requested technical specification change for Sequoyah Nuclear Plant units 1 and 2 by February 1, 1979, so that we may proceed with our implementation of the revised leak rate test criteria.
The enclosed material will be included in Amendment 60 to the Sequoyah Nuclear Plant FSAR.
Very truly yours, E. Gillel nd g
Assistant Manager of Power Enclosure (10)
\\
7901240107 g
s
3 SNP-24
,c--
kw.
f ENVIR0!CfENTAL CONSEQUENCES OF A POSTULATED LOSS 0.F. COOLANT 15.5.3 ACCIDE'iT A oJ s4 f
The results.of analys-s presented in.this section demonstrate that the amounts of radioactivity released to the environment in the event of 'a los s--o fwo olan t accident do not result in doses which exceed the guideline values specified in a 10CFR100.
W (t) ra reatht4e-aar.lysI, --62}-a-conservat-ive-y
-3hree -an+1ysee-are p-rfm=ed.
analysisenO&)'+An analysis basegn Regulaty Guide 1.4 (Reference 3)pu pM
-uA.
3 The paranaters used for eaciM -these--andyseo-ar-e listed in Table 15.5-
- 4.. A-se n si t,1 wi t y-st udy-f o r---va ni ous-o E--the s% par amat er s-l udi scei--
-in-AppendiM5IF,-Ior--th--core act+ +t y--releeWRegula'terpGtride--l-4).
In addLtion, an evaluation of the dose to control room operators and an evalu-ation of the of f site dose resulti ag from purging the containment for hydrogen 24 control arc presented.
Fission Product Release to the C ontainment Following a postulated doubic-ended rupture of a reactor ' coolant pipe with subsequent blowdown, the Emergency Core Cooling Systen keeps cladding temperatures well below melting, and linits zirconium-water reactions to an insigniticant level, assuring that the core recains intact and in place. As a result of the increase in cladding temperature and rapid depressurization of the core, however, some cladding failure f
oay occur in the hottest regions of the core. Thus, e fraction of the
~
('
fission products accumulated in the pellet-cladding gap eay be released to the reactor coolant systen and thereby to the primary containment.
- g. 3. ~, L d 7 the radiological consequences of a fission ygoduct
.In order to evaluate off-site deses verd calculated for ( A d % E Tission a
release, ti e product release case n.
Cat >- Activity-Releasa-(Conservat-iveJAnalysi&)-
fission product release case (conservative analysis) it,/p.
x In th'e~first vas assuaed that the entire inventory of volatile fission products,. contained in the pallet-claddin3 rep is released. Of this gap inventory,9 00%
of the halogens and.1007. of the nchle gases are assu-ed to b'c released to the containment. Of t.he fission product iodine re16ased t o the containnent, 50% is considered to he available for leakage, uhile the remair.;ng 50% is assuced to cc2 dense on t,he various structural surfaces in the containment.
) c
's 1hus, a total of 100% of,the/ noble gas gap activity, and 50% of the halogen gap activity,is' assumed to be availabic'irmediately for leakage froa the primary,c66tainment.
N l
~
Of the halogen activity availabic for release, it is further~bscuced
/
that-91% is in c3cnental form, 4% in r. ethyl forn and 5% in particulate fofm.
_ _ _ _. ) _
D f.
P 15.5-4 July 26, 1974
s Core Activity Release (Regulatory Guide 1.4 Analysis)
Itr-the-second-fission-produet-release--case--(Regulatory-Guidslr4 ana-lysi The of f-site doses resulting from a hypothetical accident assuming Activity releases of these core activity releases have been analyzed.
d nagnitudes have a considerably lower probability than those associatetNe "
Fpr the ana.l sis of this Jiy?.ot.hetical... case,J m.
.ll
.s i
ca.
s al with a gaEl release 4 myl-arf,,,,,,, I c./,2 m a d...
n.1.ta.al-ac t4vi
.l.v, t(> de t er. r2.nc thea. v.n.-
p,.m.
. ty.re,t.t ano 6.ar e
6 ossurr.pta ons-ps%.s e
.. - s
-e th.te he.t-fissrlon-pro u.c.tsl L
h.L.3,_>
< :.s u
.-s
~
vi he.s 2c-1;ap-rel.e.:ase-c.a.nsynx, cept.s s-a-La..a...for-the.
.,4 se c
r e
t,
.m t.o. J...n os t-- u s A
,...s
-act,Lvttv-ra anse.4., e (.. g so y
-t 2nventor y-of 1the-en t-i r e--c ore-a s-u'se d--a.
r ow.
1 o.
. n.
r,1 rr-s L,d,,r.1 A
o f..
3 c.s,ne4 h
v.,,6 3,.
.cof.
,3 u A to
- p.,
r-....$
Thus, a total of 100% of the neble gas core inventory a un a.J...., a A
.~
Of the halogen activity available for from the primary containment.is further assumed that 91% is in elemental form, 4%
release, it nethyl fc,rn and 5% in particulate form.
The fission product invgtories used for -both the core aml-the-gap activity release cases rA listed in Table 15.1-4.
nre s
Fr-imar-y-Cont s rert-Model
.q"n e-qu an t i ty-o f-a c t iv i t y -r el e a s ed-f r ow-t he-con t a in me n t-u to represent upper, vi th a r:ulti-volume nodel of the containment, Jour \\and ice condenser regions of the containment.
there are no sources of activity following the f
If it is ' assumed that initial instantaneous release of fission products to the, containment, 5
if to time in each of the well-tixed f-the change of activity with respect
\\
p volumes is described by the following equations:
j-dA F
F3,'3_
1 2.1_
y 4y y
dt V
2
'V D
L 1
=
2
'1,\\
dA F
F A _
2,1
-)
,A g
2 3,2 L
2
=
_dt V
3 V
\\
2 2
\\ x
/
3 1,3 (1 nice)~'
F dA F
12, 3
Ds 3
V
- o
=
- 1. /
_dt V
3
/
,/
ITnere
/
o lower eck ian cffcctive flou rate from upper region F
2 p, region
/
nou rau Mm ice comknsa ug%n
& ck fan c W ct he S
F
=
3,,
b-to upper._ region D\\
15.5-5
Deck fan effective-flou_ rate from lower-region to_ico F.-
.. =
I'3 condenser region Activity of a nuclide in lower volume as a function of time A
=
p y
1ctivity of a nuclide in upper region as a functio of time A
=
'N Activity of a nuclide in ice condenser region as a function A
=
of time Free volume o lower volume V
=
1 V
Free volume of uppe volume 2
V
=, Free volume of ice cond' ens 3
DecayconstantofanuclidNe A"
=
/
Removal rate due to containment 1 akage A
=
L Ice condenser efficiency for halogen form
=
n.1Ce time t
=
'Ihe above set of dif ferential equations are solved simultaneously for each isoto' (e.g. elemental, methyl, particulatef. pc and for each halogen formFron this the isotopic concentrations airb containmInt as a function of time and the integrated isotopic leakage f
fror3 the containment for a given time period can be obtained. Parametere u,e'd in the loss-of-coolant accident analysis are listed in Table n
6%5-4.
Modeling of Retaoval Process For fission products other than iodine, the only renoval process considered is radioactive decay..The dec-ay--constants-used-in-the-calculat-ions are lis4ed-in-AppenMx-15A, The fission product iodine is assumed to be present in the containment atnosphere in elemental, organic, and particulate form.
For-both c are-: + gep-a-t ir t,.
m..,
at n assumec :nat 91% of the iodine available for leakage from the containment is in elemental (i.e., 12 vap r) form, 4% is assuned to be in the form of organic iodine compounds (e.g.,
methyl iodide), and 5% is assumed to be adsorbed on airborne particulate matter.
In this analysis it uas conservatively assumed that the organic and particulate forms of iodine are not subject to any removal processes other than radioactive de ay and leakage from the containment.
The effectiveness of R ice condenser for elemental iodine removal is described in Appendix A to Chapter 6.
For the calculation of doses
-for-both the ga;>-and core-releasa-sour-cm the ice condenser was treated r
a P
15.5-6
%l er~m pry.4..,, /
-6 um.
.., u,, i f-o
- c. A.,., e 11,
.d..., ~,,4, a. U,
- x.,e J.,, L J ca.-a,1(c...L.s.
a n--a-r e a ir c ula t-ion-f-i-i t e r-wi thin-th e-i c e -b e d-v o l tue.
The time dependent ice condenser iodine removal efficiencien for hot-h-th@Eonservati.ve
[
and Regulatory Guide 1.4 analysts th given in Table 15.5-5.
- fhe s e nsi t-iv-ity-of-iod-ine-a c t-ivi ty-re-lea s e s-t o - th e-ic e-c o n d e n s e r--ef-f-ie-ien cy-in-discussed-in-AppemMx-M.
Ice' Condenser
%c ice condenser is designed to lianit the leakage of airborne activity from the containment in the event of a loss-of-coolant accident.. This is accomplished by the removal of heat released t o the containtcent during the accident to the extent necessary to initially maintain that structure belou design pressure and then reduce Ihe pressure to near atmospheric. The addition of an alkaline solution such as sodium tetraborate enhances the iodine removal qualities of : t he nelting ice to a point where credit can be assumed in the radiological analyses.
The operation of the containment deck f ans is delayed for '10 minutes following the loss--of-coolant accident. This delay in fan operation yicids an initial inlet steam-air mixture int o',the ice condenner of greater than 90% steam by volume which results in more efficient iodine removal by the ice condenser.
As a result of crperimental and analytical effort.s, the ice condenser system has been proven to be an effective passive systen for removing iodine from the containn.nt atmosphere following a loss-of-coolant accident.
(Reference 14, Ulth respect to iodine removal by the ice condenser, the following assumptions were made:
l.
He ice condenser is only ef f ect ive in removing airborne elemental iodine from the containment ah'iosphere.
.z,,..
.L p.., L J r c..n l p r.ms.
2.
Le ice condenser is modeled an a recirculat.-ion-filltr-30cated
-in-the ice-condenser-vcFlune.
-3 Activity-transfer-be tueen-the-various-volumes in-the-contminnent is-due-to--th+- for eed--ventilat wn of--the_cc.n tainme.nt deck f ana acented-between-the-upps--and 't over-con t ai nmen to.
3 The ice condenser is no longer ef f ect ive in removing e3cnsental
-4:
iodine af ter all of the ice has been melted using the most con -
j servative assumptions.
Primary'Contninment Leak Rate The primary containment leak rate used in hot,h--the!.c t
conservatSve and-Regulatory Guide 1.4 analysis is the design basis leak rate guaranteed in the technical specifications regarding containment Icahnge. For IP 15.5-7
i
(~
i the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following the accident, the leak rate was assuned
.( !
to be 0.25 percent per day and the leak rate was assumed to be 0.125 O
percent per day for the remainder of the 30-day period.
l The Icakage f rom the prinary containment can follow either of two paths:
(1) leakage into the annulus volume, or (2) through-line leakage of rocas in the auxiliary building (see Figure 15.5-4).
The environmental cffects of W h.,tl gap _and core release source events hYl!8en analyzed thal geercenENE the total primary containment leakage on the basis goes to the auxiliary E ilidTiK k g.
Auxiliary Euildint; Release Path The auxiliary building allows holdup and is normally ventilated by the auxiliary building ventilation systen.
However, upon intiation of the SIS signal follouing a loss of coolant accident, the normal ventilation systems to all areas of the auxiliary building are shutdown and isolated. Upon auxiliary building isolation the Auxiliary Building Gas Treatment System (AECTS) is activated to provide ventilation of the,
',his systen T
area and filtration of the exhaust to the atmosphere.
17 is described in Subsection 6.3.3.
Fission products which leak from the primary containment to areas of the auxiliary building vill be diluted in the room atmosphere and vill travel via ducts and other rooms to the fuel handling area or the vaste packaging area where the suctions for the Auxiliary Building g-Gas Treatment Systen are located. The cean holdup time for airborne t'
f activity in the auxiliary building areas other than the fuel handling area is greater than one hour with the auxiliary building isolated and both trains of the AUGTS operating.
For the reference case, it has been conservatively assumed in the estimation of activity releases the auxilia.s building is, im.med..iat. Y, released _ d a b k.q.,
that acti;ity leaking to rv o -
. ~
s
.o, n
n
.. t
.g "
envuonae at,y,arough... -tne AEGTS filter systen.
In the egulatory.a w
., c to tue Guide 1.4 analysig the ABGTS, filter systen ig. assumed to have renoval of ficiencies of SU percent, 10' percent and 50 percent for elemental, organic and particulate iodines, respectively.
In-the-conserva t-ive analyss-.the._1dXIIS_ir-assumal to-have-r emoval-ef fielene-ien-o f-99 percent,
05-p e r c e n t-a nd-9 9-pe r c e n t-f or-el eme n tal rorganic-and-particulate-iodines, respectively - Thc. sensitivity-of-activity _nclea.ses-to-the-delny-before chwt-ire-thn--91ery4-;,ildire-i., J _ ceM:--Appendix-15R.
The auxiliary building internal pressure vill be maintained at less 17 than etcospheric during normal operation (See Subsection 9.4.2), thereby prevent ing release to the envi.ronment withog, filtration following a LOCA.
Refer to the response toAECquestionf.ll for more detailed f
17 discussion of this capability. The annulus pressure uill be maintained less than the auxiliary building internal pressure during normal operation, therefore, any leakage b-tueen the tuo volumes following a LOCA vill be into the annulun.
It has been assumed conservatively that there is no leakage via this route.
-Shield Buildine, Releases The presence of the annulus betueen the containment vessel and the chieldbuildingreduce$rtheprobabilityofdirect leakage fron the c.4.h.s.4 k
P March 11,1974 r c
~
vessel to the atmosphere and allows holdup, dilution, mixing,-an ~ sg
{
plate-out of fission products in the shield building g'tTie aniiulIsOnety ;TeTce
(
of the prin:.ty containment leakage is assumed to go in f
volume in t.he reference case.and-other-cases presented-in-Appendix 15n.
'ihe initial pressure in the annulus is less than atmospheric. After blowdown, the annulus pressure trill increase rapidly due to expansion of the containment vessel as a result of primary containment atmosphere temperature and pressure increases. The annulus pressure will continue to rise due to heating of the annulus atmosphere by conduction through the containment vessel.
After a delay of 30 seconds, the Emergency Gas Treatment System (ECTS) vill be operating at full flow to maintain the annulus pressure to belou atmospheric pressure.
The EGTS.is essentially an annulus recirculation sys tem with pressure activated valves ubich allow part of the system flou to be exhausted to atmosphere to maintain a " negative" annulus pressure.
The system includes absolute and impreg-nated charcoal filters f or removal of halogens.
The EGTS combined uith AUGTS ensures that all prirary containment leakage is filtered before release to the atmosphere, yd A The EGTS suction in the annulus are located at the top of the containment 3
dome, while nearly all penetrations are located near the bottom of the containcent (see Subsection 5.1.2), thereby minimizing the probability of lenhage directly from the primary containment into the ECTS.
- llouever,
,(
it has been conservatively asst'med for the reference case that, after
)
the initial 30 second period,38 rcent of the pr.imary containment
,1cah' age to the Annulus voluSe (or w ce n t = of--th e-t-e t-al--pM aar-y-c o n t,a4 n+-e nt
~'
'leakag(-), goes -direc t19 to the EGTS suct ioW. ' Th e-de n s i t i-v-I t-y-of-a c t4v-1-ty--
.r el ea se s-t o-tM s-a s sunp e-len-ar e-di-s eu s sed-in-App end ix-1-S h l
Th o-r emair.ing-SO-r.e rc e n t-o f-th e-pr-imary-c on t ainme n t-l e ak aght o--the-nanulue.-h1 -p+rcent--of-the-total-primary-containment-leakage)-ie-assn :ed
.to-go-t o--the annulus.- volume-(al'ohg_ wit,h -the-reci rcula tion f-lo.e-fron
.the-EGTS)-where_ it-in heldup-before-entering -Lhe ECTS-suction. The holdup time is a function of the EGTS flou and exhaust rates as well as the annulus volume). The mean holdup time (h) bef ore release to the atmosphere it, defined as:
0.5 x Vol.me of the Annulus e
=-
'll Exhaust Flow from the EG15 to A nosphere It is conservatively assumed that only 50% of the annulus free volume
/
- L pm -lb d - i is available for mixing of activity. /)
m.. -
auwd E c,rs f/hn a T r a ns f o r-o f-ac t iv i ty-f rom--th e-a nnulus-volume-t o-th 6ECTS-s u e t4ow-is-assumed to.be a statistical proccas similar mathemat;ically to the
~
decay process [(1.e. Jhe rate of removal from-tliE~ annulus is proportional ?
to the total activity in'the annulus) c^fiIis assumption, uhile compatible with complete mixing ofj;he-aniiultis'voluge, does not require any mixing to take place to,be v611d. Ilouever, becau'sPofsthe low ECTS flou rate (compardito the annulus volume), the thermaUnvection due
[
-t o h,e a t ing--o f-th e - c on t a inmen t - vessel,- and-th e-reln l i ve-l oc at lidih c
(c1 15.5-9
., -. - ~ __
4f..the ECTS.suctionL(at the top-oE-tha doma-)-and-the-ECTLre.circulatiou exhaustm.(at the_ base of thc. anmilns), a high degrce of nixing. can.
~
-be-expec ted.- -The-mean-holdup-tiane-neglects-travel--time-in-the-EGTS.
~
k(")
tioreover, use of-n-mean holdup-tima-ia-conservative,-since in fact hearly all of the Icakage is expected to occur in the area of the penetrations near the base of the annulus uhere it would he diluted %
Table 15.5-by the ECTS flow and slowly travel to the ECTS suction.
6 shous the variation of ECTS exhaust and recirculation flow rates, with time af ter the LOCA, which was used for calculation of activity releases for. bot-h the conservative and Regulatory Guide 1.4 analysts.
~
The flou path of fission products which are drawn into the air handling systems is shown schematically is Figure 15.5-4 where-Ir-is-the-f raet-ion of-primacy containment-leakage-going-to-the--shio1d buiriding which does-not-nix-with--the-shield huilding air, Effectiveness of Double Containment Design The analysis verr-led-ont--with-the predose codc ;-uhi ch-represents-the-
-l ou e r-a n4-u pper-c on t a4 n me n t--vol t.ees7-a s-uc i l-a s-th e-i c e-co n d e ns e has demonstrated clearly the beacfits of and-the-annulus-volu %
As vould be expected for a double the double containment concept.
the second barrier acts as an ef fective hold-barrier arrangement, up tank, resulting in substantial reduction in the tuo-hour inhalation The expected off-site doses for the and uhole body immersion doses.
the low population zone are also substantially reduced, 30-day period at since the holdup process is ef fective for the duration of the accident.
flow rate is dependent on the rate of air inlenhage
[
The ECTS exhaust N
after about 20 minutes following blowdown f
to the annulus.
In fact, of the reactor vessel the ECTS exhaust flow is equal to the air inleakage Studies [5] made of Icak rates from typical concrete buildings type have resulted in leak rates from 4 to 8 percent per day rate.
of this Although the pressare a pressure differentici of 14 inches of uater.
dif ferential in this case vill be nuch lower than this value, it has at been assuned that a shield building inleakage flow of 100 SCFI! (about the 30-day period, for both 34 percent per day) exists throughoutThis inleakage flow includes leak ~
.t h e-ga p-a ml-c or e-r el ea w--s emcces isolation valves age past ventilation system primary containmentf ails in the open posit. ion.
assuming that a single isolation valve yrergency Cas Treatment Systen Filter Efficiencies The Emergency Cas Treatnent System takes suction from the annulus, and gases are drawn through tuo banks of impregnated charcoal the exhaust Sufficient filter c pacity is provided to contain filters in r.eries.
inorganic, organic, and particulate available for leakage.
all iodinos, Since the air in the annulus is dry, filter ef ficiencies of greater than 99 percent are at tainable. Tes ts reported in ORNL-NSIC-4 (Reference
- 6) have demonstrated that inorganic halogen removal ef ficiencies greater than 99.99 percent can he expected uith low relative hu i ity.
To further ba incorporated casure high filter efficiency, heaters and demisters wi m the filters, resulting in a relative humidity of less than 70 percent in the air entering the filters.
{
upstream of N.
P O
\\
15.5-10
-In-the-analysis of-tinr gahrelcase--sourcyhowevery-a--remova-1-efficiency of-99-perc en t-f or-el enenen1-a nd--pa e t-ietria ee--iodine-ana-95% f or-or ganle g
.iod ine ic -a ssumul-f or-ca c h-o f-t he-tur-f 11 ter-ba nka-in-s e r i ew-r esult;ing
'q f
-in an overall c f fitiency of_9 9.99-percent-f or--elemental-and-paet-ieula te.
Jodines-and-99 75% for-methyl iodine L
For -the analysis of-the-core-releem.-souree, overall filter synten effi-j ciencies for the two filter banks of 95 percent, 90 percent and 95 percent were assumed for inorganic, organic and particulate forms, respectively.
Discussion of Results The gamma, beta and thyroid doses for the loss of coolant accident at the site boundary and the low population zone are given in Table 15.5-7 for each-c4-the analyses presented in this section. The dose limits for this accident are defined in 10CFR100 (25 rem uhole body and 300 ren thyroid).
Even f or t-h8A>st conservative analysis the doses are well within the 10CER100 guidelines.
Thn dases--f-roa-a-J oss-o f-co+1*nt a c c i d e n t-wi t h-a L1-s a f eg ua r d s-opera t-i n g-as-d es-ign ed-cocr espo nds-to-those-g-1 ven-f o r-t h e-r caList-i c-a nal-y s is-in--Tal4 e-1-5d-7.
lue e.ECec t.iveness-of-tha--secondar-y-conta-inment-is-shown-by-the-reswLt-s-r obtained 'for-the. core activity release (Regulatcry Guide 1d) in Appendix 15B, uhich descriht'all possible combinatioon.-of' lea'kage paths t cough the annulus and auxiliary bui$liit/.-Tr(results, given in Table ISB-1 through 15B-3 and 'Eigures~'15B-1 through 15B li-also demonstrate that
~~~
system is~. iot -sipnificantly the ef f ec.tiveneh
- the secondary containment t
s of ie ponLu nr.ed.
g imp 4 fred uhea a-situation of_ttiniun1_or-no_ntixing_and hold-up J t.is--apparent r-thereEare.,-that fue rajor fac tor in the ef f ectiveness of the secondary contafament is its inherent capability to collect the containucat leakage f or iiltration of the radioactive iodine prior to release to the environment.
This effect is greatly enhanced by the recirculation f eature of the air handling systems, uhich forces repeated filtration passes f or the major f ract ion of the prirary containment leakage before release to the environment.
1 An analysis was performed to determine the of fsite radiological doses due 43 ;'
to purging containment atmosphere into the annulus at a rate suf ficient to limit the hydrogen concentration in the contaitunent to approximately 3%.
It was conservatively assumed that the containment conditions and hydrogen generation rates were such that pur;;in;,.es initiatcA during the second day.
Two sets of c Iculations were perforned.
in a conservative case (Case 1) the total release from the conta inment immediately entered the air cleanup subsystem intake uith no mixing in the annulus.
In a more realistic case (Case 2), the purge gases were assuned to nix with the annulus atcosphere before entering the air cleanup subsysten intake. The off site doses are shown in Table 15.5-7a.
Loss of Coolant Accident - Control Room Operator Doses In accordance with General Design Criterion 19, the control room venti-lation system and shielding have been designed to limit whole body gamaa f(
dose during an accident period to 5 rem.
'1hyroid dose is limited to 30 43 rem and beta skin doce should not exceed 30 ren.
3 g0 15.5-11 Decceber 29, 1976
. Q'
4.
The concentration as a function of distance along the access k(,
road was determined from the atmospheric ditf usion model.
5.
One one-way trip first day, one round-trip / day 2d through 30th f
day.
6.
Other parameters used in the calculation ware taken from Murphy and Campe[10]. They are:
1)
Occupancy Adjusteent Factors:
100 percent occupancy 0-24 hours 60 percent occupancy 1-4 days 40 percent occupancy 4-30 daya
- 2) Wind Speed Factors:
5th percentile vind opeed 0-8 hours 10th percentile wind speed 8-24 hours 20th percentile wind speed 1-4 days 40th percentile wind speed 4-30 days 4'
It was also assumed that initially the make-up cir intake would be through the vent admitting the highest radioisotope concentration, but that the Main Control Room personnel could switch intake vents 2 8' hours af ter the accident in order to admit a minicum of Airborne Activity to the Main Control Room via the nake-up airflow.
The whole body and thyroid doses from the radiation sources discussed above are presented in Table 15.5-10; The dose to uhole body is below the General k
Design Criterion 19 limit of 5 ren for control roon personnel, and the
\\
thyroid dose is below the limit of 30 rem.
The total calculated beta dose
- 6. % i h 41 rea.
This is also within acceptable limits.
Since the whole body f
dose permitted under.Ceneral Design Criterion 19, App. A,10CFR Part 50, is the same as the yearly dose under 5 20.101(a), 10CFR20, the same relative doses to different parts of.the body should apply.
The calculated beta done is below the linit for all specified organs.
The blood forning organs are beyond the rcnge of the betas, and the gonads are normally protected by clothing and skin.
A breakdova of the calculated beta dose by isotope shous that cost of the dose (about 92%) is due to 133Xe which has a maximum beta energy of 0.346 McV, and a corresponding average energy of 0.1005 MeV.
From Berger and Seltzer the range of 0.35 MeV electrons in water is 0.104 The thickness of the cornea, anterior chamber, and f ris is approxi-cm.
nately 0.3 ce; therefore, even assuming all beta from 133Xe have taximum energy, none vill reach the lens ro thcr the dose from this source is zero.
If 133Xe is clicinated froa consideration on the above grounds, the re-raining isotopes contribute only.k3 rem which is under the linit for t/7 dose to the lens of the eye.
03 t'
9
(~~
15.5-17 April 29, 1977
').
79
.:~.
t; e,
TAELE 15.5-4 t6
, s
- \\
PAIW!ETERS USED IN LCCA ANALYSES
\\calisticf
\\ oncervctiv Regulatory Ouide 1.
alysic(1)/
Ar tlysis (1)
Analysis Core thernal power 35S2 int 35 2 >Nt 3532 1."Je
\\
6 3
6 3
6 3
Primary centainment free volt:me 1.241 x 10 ft 1.241 x 10 ft 1.241 x 10 ft 5
3
\\
/ 5 3
5 3
7.16\\x110 ft 7.16 x l'0 ft 7.16 x 10 ft Upper primary containment free volume I 5 3
/ 5 3
5 3
Lower primary containment free volume 4.0 x 10 ft.
4.0 x 10 ft 4.0 x 10 ft If 5 3
1.25;x/
5 3
5 3
10 ft 1.25 x 10 ft
- u Ice condenser free volume 1.25 v 10 ft t5 5
3
'l 5
3 5
3 l',
i d
Annulus free voice 3.75 x'10 ft 3.75 x 10 ft 3.75 x 10 ft l\\
\\
Pri=ary containment deck fan flow rate 80,000*cfm 40,000 cfm 40,000 cfm
/
Number of deck fcns assumed operating 2 of 2 1 of 2 1 of 2
\\
Activity relenscl to primary contain-ent end evcilabic for relcace noble gcces Inyantory in one 10,0%of; gap 100% of core g
RCS volum i vento y.
inventory iodine Iqventory in one 50% of gap 25% of core tventor' inventory RGS volume 1j Picteout of iodine cetivity released to 50%
50%
50%
/o
[
(1) Reference LOCA.
9 9.h
?
2%"
I o
TABLE 15,5-4 (Cont'd)
PARAM2TE IS I' SED IN LOCA ANALYSES I
healistic Conservative Regulatory Guide 1.4
.! nalysis Analysis' Analysis A
h
\\
1 t
l
}
Forn of iodine activity in primary containment available for release I
i elenental iodinc 91%
91".
I 91%
\\
e.cthyl iodinc 4 %.
4%
/
4%
s 1
I particulate iodinc 5%
l 5%
5%
Ice condenser renoval efficiency 1.0
/
Se Table 15.5-5 See Tabic 15.5-5 for elemental iodine I
w u,
\\ l Primary containment Icak rate 0.125% per day 0.25% per day 0.25% per day vi 6,
(0-24' hours) 0--2A hours) 0-24 hours) u p
\\;
0.12,5*? per day 0.125% per day 0.03125% per day 7
(1-30 days)
(}.-3pdays)
(1--30 days)
?creent of primary contain= cat leakage
.10% j( "
10%
10%- 26 %
to auxiliary building j
A2GTS filter efficiencies I
99%,
99 90% $f $
- c d.4 y. -
clc-.ce.. "1 4
j nethyl icdinc 99h 95,%
70%' cio 7.
particulate icdinc 99 9%
9%
90%~ N.
Delay tiec of activity in auxiliary 1.
hour 0.0 hour0 days <br />0 hours <br />0 weeks <br />0 months <br /> OTO-he.rr-o. 3 lic t
builc..ing f
Io m a y fe,s Ly n c.)
.Q d.a.9 Lech cGTS total :f,Ilep yu A3:vs ar<
zf'00 ci~-
' 000.fm 4000 Cfn
.nta4c flow i
/100% j I
50%
Percent of annulus free volu=c availabic for 100%
e.ixing of activity
/o
/
8
- 5T'h j 'Dg i
T TABLE 15.5-4 (Cont'd)
FARMIETERS USED IN LOCA ANALYSES, cncervatkve gegulatory Guide 1.
st c u
AU3-VSic Analysis See Table 15.5-6 ScTayle15.5-6 5-6
\\
EGTS cxhaust flow rate 1 of 2 l 'of 2/
10r Number of ECTS air handling unite 7
assumed operating
/
\\ !
\\aI ECTS filter efficiencies
)9f 95%
'\\
clemental iodine 99.99%
99.75%
90%
=cthyl iodine 99.99%
95%
i 99.9999%
~,
particulate iodine G
Percen&or, primary contain ent-Icakage nixed in 40$,h 0%, $
90%-
c
\\
d, annulus rree-volume-during-initial-30 f!
o acconds-post-LOCA 9y/
'9%~
?orcent-of primary. containment--Icakage-to ECTS 0,og )
"f
\\
i j
{' r nancling -units suction - af ter-initial 1,
f 00-seconds' post-LOCA ~
-81%-~Y*~
k 90%'
9-Pe r c en t-o f-pr i=ary__containmen t-le aka ge-mixed-in annulus-voluna._af tcr-initial--30-seconds
\\
i i
pos t-LOCA-l j
An?.ual.verage
" Accident'k l5 A)
(sce Accident (see avpragedTover all-ppendix Appendix 15A)
Metecrolog"#
sectors (2{
l 1
0
- c. n]c. a mnt len bp be gg75 g o ep, 7
p e = ~.s ry 1 e rr.ent sr kdl. $ u-.k s d en av
-bec/m -- at-cite-boundarv-based-en auxi11ary-buil-dint-and~sliicid-building _ve:tt _cxhaus t s -
-(2 )_7. 23_.2:._10 3
-as-re-lease-:: enc ;-_5.9 3 x-.10 7-sec/m -at-1cw pepulation--zone.
Op
f.
c*
TABLE 15.5-5 ICE CO'IDENSER 10DItiE REMOVAL EFFICIENCY Iodine Renoval Time Interval Efficiency Post LOCA (Hours)_
0.96 0.0 to 0.106 0.84 0.106 to 0.133 0.71 O.133 to 0.244 0.67 0.244 to 0.333 0.64 0.383 to 0.522 0.62 0.522 to 0.578 0.30 0.578 to 0.606
- 0. 0' 0.606 to 720 4" ~
I
.I (1)The ice condenser removal ef ficiencies given in the above tabic are used for both-the conservative.and Regulatory Guide 1.4 analyses. The inlet stcan-air nixture cocing into the ice condenser is greater than 90% secam by volume initially due to the delaying of the operation of the containment deck fans. Uithout the delay of operation of the deck fans the amount of steam by volume in the inlet nixture initially would be much lower and the ice condenser iodine removal ef ficiencies would be reduced.
0
\\
x-(*% 0.
15.5-37
Revi ed y Amend. 19, day
.3, 1<) /4 f' m.
(.-
c.f TABLE 15.5-7 OFF-SITE DOSES FROM LOSS OF COOLANT ACCIDENT Thyroid Dose (Rea)
Site Boundary Los Population Zone (0-2 hours)
(0-30 days) 556 neters 4828 neters J v.l ', C :
-;c' l. . 10 --
- 1. ',. 10~
~2
-?
.Gon9ervat-i-eAnr ', c =-
6-%.el0 1 ; 9=5=Id--
2<3 7--I d 1 8 o 52 J "# 3 0 Reg. Guide 1.4 Analysis 10 CFR 100 Guidelines 300 300 Carna and Beta Doses (Rem)
Site Boundary Loti Population Zone (0-2 hours)
(0-30 days) 556 neters 4828 neters Camma Beta Canma Ecta I
Dose Dose Dese Dose JhliciwAnalyM b-1-x-10 6 Ar2-r10 ~-E 9A. =-10 5r %+=10'7
-8 Co:rerva t-ive--Ader 7 4-~-10
.7 r-5 10 2.5. 10'3 9 r9-'-lO-3
-3
-3 Reg. Guide 1.4 Anal, sis h3' 8.o h 9- '/. 3 7 4 r-10 1 A S-x---10
-1
- t. 3
- .1 10 CFR 100 Guidelines 25*
25*
~
- Taole Body Dose
\\
.m 15.5-39
Revised by Amendment 43, Dece=ber 29, 1976
- D TABLE 15.5-8 Atmospheric Dilution Factors at Control Building Dilutiog) Factor Time Period (nec/m
__ (hour)
-3 0 - TL 1.59 x 10
'I g,eq xeo 1-s
~'
2.-7& E#10 '
8 - 24 1.67 x 10
~
24 - 96
-5 96 - 720 8.73 x 10 9
a O
e S
e 0\\
15.5-40
Revised by Amendment 43, Decem;er 29, 1976 TABLE 15.5-10 CONTROL ROOM PERSO:mEL DOSE FOR DBA POST-ACCIDEtiT PERIOD s
Personnel Dose Source ilhole Body Beta Dose Thyroid Gamma Dose (rem) *
(rea)
(rea)*
Control roon airborne activity Or102 o, p 4 5709 5.73 9715 19.2 8 External cloud shine 0.001 0
0 Contair. ment shine 40 0
0 Floor, adjacent structures / shine 0.023 0
0 Ingress - Egress
.Gr0&9-o.o 'l Z.
-Or36-c. o T7
.4.-60 t. I 8 Total 0-1&5-o. I B Gr42 5'. 8 3 $75 go.s f
- Includes occupancy factor:
100 percent occupancy 0-24 hours 60 percent occupancy 1-4 days 40 percent occupancy 4-30 days
'O 15.5-42