ML20137N645

Proposed Tech Specs 14.2.4, Steam Generator Tube Rupture

ML20137N645
Person / Time
Site:	Point Beach
Issue date:	04/02/1997
From:	WISCONSIN ELECTRIC POWER CO.
To:
Shared Package
ML20137N644	List: ML20137N645 NPL-97-0144, Provides Supplemental Info to TS Change Requests 188 & 189, Requesting Amend to TSs Identified by Analyses Performed in Support of Operations Following Replacement of Steam Generators.Revised TS 14.2.4,encl
References
NUDOCS 9704090014
Download: ML20137N645 (13)

Text

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14.2.4 STEAM GENERATOR TUBE RUPTURE

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14.2.4.1. General ,' g

)

A complete single' tube break a' d jacent to the tube sheet in a steam generator is

] examined for two assumed situations. Since the reactor coolant pressure is

', greater than the steam generator shell side pressure, the contaminated reactor- ,

coolant discharges into the secondary system.

The'. activity release'. is limited by the concentration in the reactor coolant, -

which is conservatively assumed to arise from 1% defective fuel cladding. The activity release is further limited by operator action to terminate the primary j 2

lto secondary fluid leakage and the releases from the affected steam generator to the' atmosphere.

[ Method of Analysis +

j l A detailed time sequence of events is presented from occurrence of the assumed steam generator s.ube rupture until the primary 'to secondary break flow and i

e release from the affected steam generator to the atmosphere have been terminated. l Resultant radionuclide releases to atmosphere have been evaluated s:pr:t:1y-t assuming that off-site power h weihble in = cese ed is lost h th etL .

.T h;'.'.,,--;ite k J F= u..... .

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g. The potential for an increased radioactive release to the environment due to steam generator tube bundle uncovery has been evaluated (Reference 3). Uncovery ,

does not !,ignificantly increase the radiological consequences associated with the j

SGTR accident. The probability of a significant release due to non-SGTR events,

}.. including the effects of tube uncovery, is sufficiently low to exciude such events from consideration. The NRC agrees with the position that the effects of j on R eve t s negligib e (Reference 4).

l

[ 14.2.4.-2 Analysis Assumina Minimum Antliny Feedwater and Off-Site  !

Power are Available i

The-sequence of events'following tube rupture is as follows:

E d -1.- . Primary leakage takes place initially at a high rate (~)Rf lbm/sec) but

~p7 rapidly drops to a lower leakage rate (74'l lbm/sec).

. "'55 9704090014 970402 y 14.2.4-1 June 1994 i d POR ADOCK 05000266g i P PDR g_

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14.2.4.4 Radioloaical consecuences of a steam Generator l Tube Ruoture Accident l

This section presents an evaluation of the offsite consequences of a

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steam generator tube rupture accident.

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l ;n:20I..- 1 L.d'.t:x; f d'-* - -

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1 Assumotions: The following assumptions were used in the analysis of f I

the off-site consequences: l

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oC' j

[M/} E ine equisier~ primary coo J. actlvity i equivaient factive fuel. ef. Table 9. (See note 1 page 14.2. 9) i a  !

,2 . With ortsa ,to secondary age assuzad r to the pc ulated i I l

accident, the uilibrium a vity in the s ndary sys., is f' l Jected assumin e followin f l

i X .

s s 1

a. Pr ry to seconda takage is e ly distribu both s >

j steam nerators.

l unit vol. aa t b The iodine p tior. factor $Amountiod unt iodine / vol. liquid %

assumed to be 1 in steas g rators and blowdown tank  :

Amo n odine/ unit k aas '

The ine partition tor , Amount i

/untt vol. id l l s ass' to be 10" in densers.

Ns,-

s wl process' sisted of

d. The ondar stem activity

{ lease, blowd tank radioac e dec air ejector venting, blood tank liquid arge.

4

e. T lowdown ra rou t as generator s continuous.

j Addi i paramet used t alculate th quilibrica n the sec ary syst re present Ln Table af.tiviti

.2.4-1.

k ,

i 14.2.4-5

Insert 1 (on FSAR page 14.2.4-5 where marked) ,

1. Both pre-accident and accident initiated lodine spikes are analyzed. For the pre-accident iodine spike it is assumed that a reactor transient has occurred prior to the steam generator tube rupture and has raised the RCS iodine concentration tff#pCi/gm of dose equivalent (DE) I-131. For the accident initiated iodine spike , the reactor trip associated with the steam generator tube rupture creates an i iodine spike in the RCS which increases the iodine release rate from the fuel to the RCS to a value 500 times greater than the release rate corresponding to the maximum equilibrium RCS Technical Specification concentration of k0 Ci/gm of DE I-131. The duration of the accident initiated iodine spike is J4 hours. 0f

1. G

2. The noble gas activity concentration in the RCS at the time the accident occurs is based on a fu_e!

defect level of 1.0%. This is approximately equal to the Technical Specification value of 100/E pCi/gm for gross radioactivity.

3. The iodine activity concentration of the secondary coolant at the time the steam generator tube rupture occurs is assumed to be equivalent to the Technical Specification limit ofJXpCi/cc of I-131.

/.O

4. The amount of primary to secondary steam generator tube leakage in the intact steam generator is assumed to be equal to the Technical Specification limit for a single steam generator of 500 gallons / day.

5. No credit for iodine removal is taken for any steam released to the condenser prior to reactor trip and concurrent loss of offsite power.

6. An iodine partition factor in the steam generators is used as follows:

0.ol SW(curies !/gm steam + curies I/gm water)

7. All noble gas activity carried over to the' secondary side is assumed to be immedi=ly released to the outside atmosphere.

4

1 squil ~rium ca. entrati of iodi - and no e gas in the se dary's e versu assumed imary to- condary akas ates, with s isary l a'nt ac vities sociated *h 1% de tive 1 e giv . in Fig es 14.2. -1 thre 14.2.4I For a en lea ra , if a cool .t acti y is 1 s than th equiva t 1%

acti ty, se ndary tivity ld be rescondin _

lowe i.

0 Thirty minutes after the postulated tube rupture accident the 7

pressure between the faulted steam generator and the primary

) 23, (,00 4

y systes is equalized. Approximately' M rNHi lbs. of reactor ,

coolant is discharged to the secondary side of the faulted. steam 7

er.erator. Also, approximate @',^^.", lbs. of steam is released to the atmosphere via the ruptured steam generator curing the 7%000 ti.'s interval.

8/ Auxiliary feed water is available during the accident.

E; kb I#f. 4dhoursaftertheaccidenttheresidualheatremovalsystemis placed into operation.

, Enk4 7 // f. iff hours after the accident no further activity is released to .

I the environment.

4

/. The atmospheric dispersion factor (X/Q) at the ' site boundary (1200 meters) and at the boundary of the low population zone (9000 meter) are:

X/Q (sec/a8) g 0-2 HR HR s

.r. o t 1200 seter 24x10" datuMPA/A 9000 aster -i.GalG 'gA tr3ried 3.h/0*# .

0 Breathing rate used to calculate the thyroid dose for the

/

l accident is 3.47x10" m8/sec,,

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i 14.2.4-6 i

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1 Consecuences: ,

(th pr ary colaT1 activi asso lateo En 1% Tect1 fuel Wa '

)

pr. ary se ndary leakag rate f .3 gps, act ities 1 l

> di ctive odin and ble ga s rel sed o r vari t time riod i r .e sta os rater uhe et nr. . eiv in Tah 14.2 2.

j i The thyroid deems and body doses at the site boundary and the

&Aboundary of the low population zone are given in Table 14.2.4I7, 4 1

- m , r;/ asa acts - 7 is ess nen 45 uivai nu i uh ed  !

arfyyst eti y ea a corr and gdesk (u 1, he e

! .wk _b 1 r.I 1

r 4

Because cine is uoie in ter, co toeraai eparauo til o

the st generat . The factive econtam tion fac is fun ion of , steam op rate, nd ste generato iquid sa as l .

well a the par ion coef isnt as ntione in the as ptions

^e equi rium act ities 11 d above, furth partitio " actor of l

10 is sssu in the in con er. s is,ba upon an ine l

larti n fact of 10" less fr experi nts per reed in Ca -a

! d Russ ."*'

doses p sented i able 2.4-3 a given

< The t roid an whole bo l

,' bot condit1 s of l'a bath iren=<t r= e cr;::1..A o the public as a result of a 5 l

f ftsam generator tube rupture =:M :-; L .:;;'"::-t : ' are less j l than the permissible limits of 10 CFR Part 100.

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, 14.2.4.5 Multiole Tube Ruotures 1

A nuch larger dose, e.g., whole body dose of 25 res at the exclusion radius, can only result free the rupture of sufficient steam generator tubes to cause fuel cladding failure.

Operating experience with steam generators of the type used in this plant has not

' shown significant numbers of single gross and inmediate tube failures. Small l

leaks in a single tube which caused erosion type damage to adjacent tubes have been reported, but did not cause a rupture of the adjacent tubes.

Thus, if a 4 single tube failure were postulated ,it is probable that adjacent tubes would not 14.2.4-7

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1 be damaged but any adjacent failure would be an erosion-caused leak rather than a sudden gross failure. ,

I i To perform a rigorous analysis of the flow dynamics of blowdown through multiple '

j tube ruptures, one must understand and define mathematically the physical

configuration of the ruptures. Because no reasonable mechanism exists for the

sultiple ruptures, it is instead just as meaningful to analyze the conseqvences  ;

of a pipe rupture, equivalent in terms of discharge rate to various multiplas of )

the single tube discharge rate. l l

l Such an analysis reveals that the core cooling system will prevent clad damage j for break discharge rates equal to or smaller than that resulting from a broken j pipe between 4 in and 6 in. in diameter. The discharge rates which bracket the onset of cladding damage correspond to 18 and 40 times the discharge from a single severed steam generator tube. Actually, the ratio would be much larger

owing to the fact that the discharge from a tube failure will be limited by the back pressure in the steam generator. Ultimately, the tube discharge would l terminate when the reactor coolant systes and the steam generator reached pressure equilibrium. The operator can initiate cooldown through the unaffected steam generator.  ;

These conclusions are based on single-failure mode performances of the core cooling system. The core does not become uncovered by the calculated quiet level 1

in those cases where cladding damage is found to be prevented.

The incredibility of multiple simultaneous tube failures is supported by the

, following reasoning:

1. At the maximum operating internal pressure the tube wall sees only about 1530 psi compared with a calculated bursting pressure in excess of 11.100 psi based on ultimate strength at design temperature. j

2. The above margin applies to the longi *udinal failure modes, iaduced by hoop stress. This failure mode is the least likely to cause propagation of failure tube-to-tube. An additional factor of two applies to ultimate pressure strength in the axial direction tending to, resist double-ended failure (total factor of 14.6). .

14.2.4-8

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i Failures induced by fretting, corrosion, erosion, or fatigue are of such a

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nature as to produce tell-tale leakage in substantial quantity wnile ample l metal remains to prevent severance of the tube (a small fraction of the original tube wall section) as indicated by the margin derived in 2 above.

Thus, any incipient failures that would develop to the point of severe leakage requiring a shutdown for plugging or repair, in accordance with Section 15.3.1 of the Technical Specifications, would happen long before the large safety margin in pressure strength is lost.

~

' inary lant tivityas}~ ih,this ,

Note 1:- It should be n *ed that the alysis differs th the maxi coolan activ limits o echniQ1 l

Sp ification 15.3. . The Techn i Spe icati limits we firsh ,

1 Ort.!er ted ember 30, 79,  ;

impos on Unit 1 by Confirmato

.pril 1983, e NRC issu /

• and lat applied to Unit as well. C 76 for Uni 1a 2, r ectively, icense doents 71 an l Beach chnical these activit inits in t Poln in rporatin Spec ications. These activit limits are sed o a par tric evalua n conduc by the NRC o pical sites d are nsery ve r Plant. The echnical sp ficatt limi or Point each Nuc ary owing  ;

e ure that e resulti 2-hour dose a the site be- l genera tube rup e does not ex ed an approp 'ately all -

i as 100 limit The specif tions are i tica fract) of 10 C l nghouse Pre urizac l ,

he Stan rd Techn 1 Specift ions for We er React s, NUREG- 52, Revist 2. l l

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14.2.4-9

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REFERENCES - Section 14.2.4 )

1. L. C.- Wdtson, A. R. Bancroft . and C. W. Howlke, " Iodine Containment ey Oousing in NPD-11' AECL-1130 Atomic Energy of Canada. Limited, Chalk River, Ontario, October 27, 1950. -

2. .M'.- A. .

Styrikovich, O. I. Martynova, X. Ya. Xatkovskaya, I. Ya. Dubrovsuit,-

and I. N. Smirnova, " Transfer of Iodine from Aqueous Solutions to Saturated ,

Vapor," Atomriaya Energiya, Vol.17, No.1, pp. 45-49, July 1954.

?

3. .0. J. Mendler, *Thgdtffect of Steam Generator Tube Uncovery on Radiciodine I Release," WCAP-13132, January 1992. ,

l 4 R. C. Jones U.S. NRC, Letter to 1. A. Walsh, WOG, ' Westinghouse Owners  !

Group - Steam Generator Tube Uncovery Issue,' March 10, 1993, Attachment to WOG-93-066 dated March 31, 1993.

T 4

4 1

June 1994

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i.n I TABt.E 14.2.4-1 l THYROIO COSES AND WHOLE SC0Y COSES x STEM GENERATOR TUBE RUPTURE ACCIDENT w

i d A,u,- &.. .c :Jn2,64:%.fah_e

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• 0 - 2 HOUR 0- HOUR DOSE AT SITE BOUNOARY OOSE AT LPI' M B00Y THYR 010 M .800Y THYROID.  !

~5 5' gg ' igg l o' ' O .1 '5 g gig a M ~2 N 2 :;,J 3

_MRA10 .3:f M+M poweee  ;.;74  : . : ;^'* w l

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i B.

W.18 $"-*Am

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hhh$&!k$

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: --t C:- ! ' :i' :1-

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- 9 0.- 2 HOUR 0 - # HOUR 00SE AT SITE 800h0ARY OOSE AT L,PZ_

. THYROID aue m BODY THYROID West 800Y-Wg1. 7 q fx;0-'

M.

O.a 04K E {0S 9;* d ,

.Jkf7*~ .4/2AM*1

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.;f M:.'.? :. +rttzt9*

1 TE:

1. 61 Def t = 15 mary to onda sak a=. G F

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POINT BEACH NUCLEAR PLANT EP1P 5.2

& ' l* s EMERGENCY PLAN IMPLEMENTING l NNSR PROCEDURES Revision 8

' April 9,1996

,. , RADIOIODINE BLOCKING AND TIIYROID DOSE ACCOUNTING 1.0 GENERAL Potassium iodide, a stable iodine, saturates the iodine receptors in the thyroid gland, preventing unnecessary thyroid gland exposure from radiciodine.

2.0 REFERENCES

2.1 Letter Erwin S. Huston, M.D., dated November 6,1980, and attachment " Protection Against Radioactive Iodines."

f-2.2 NRC Information Notice No. 88-15: " Availability of U.S. Food and Drug Administration (FDA)-Approved Potassium Iodide for Use in Emergencies Involving Radioactive Iodine," April 18,1988.

2.3 NUREG-1210, "Public Protective Actions - Predetermined Criteria and Initial Actions," Volume 4, " Pilot Program: NRC Severe Reactor Accident Incident Response Training Manual," February 1987.

2.4 Memo NPM 91-0273, " Potassium Iodide - Issuance Dose level", dated Febmary 7,1991.

ch 3.0 PRECAUTIONS 3.1 Potassium iodide will only be administered to personnel as approved by Company Medical Services personnel consistent with this procedure.

3.2 The use of potassium iodide will be authorized by the Health Physics director and/or the rad / con waste manager.

33 To be effective, potassium iodide must be taken within 1 to 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> after exposure to radiciodine. If potassium iodide is administered more than 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> after an individual has suffered an acute ingestion or inhalation of radiciodine, its effectiveness as a thyroid blocking agent is less than 50 percent.

+

3.4 After an initial dose (one tablet) of potassium iodide has been administered, its continued use on a daily basis will be determined by Company Medical Services personnel, or by a designated physician.

3.5 Rosters of WE and security personnel approved to use potassium iodide as a blocking agent will be maintained at the operations support center, site boundary control center, and the control room. Personnel not authorized to take potassium iodide are 3 marked "NOT APPROVED" on the appropriate roster.

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.l- Page 1 of 4 REFERENCE USE

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,, POINT BEACH NUCLEAR PLANT EPIP 5.2 EMERGENCY PLAN IMPLEMENTING : l NNSR PROCEDURES- Revision 8 April 9,1996 s RADIOIODINE BLOCKING AND THYROID DOSE ACCOUNTING 3.6 A copy of the pharmaceutical company instructions for the use of potassium iodide tablets is reproduced on Attachment A to this procedure. This is furnished for information only.

4.0 STORAGELOCATION Single dose 130 mg tablets of potassium iodide will be stored in the emergency lockers located at the ope ations support center, site boundary control center, and the control room. .

The shelf life of potassium iodide tablets are as indicated on the pharmaceutical container.

5.0 ADMINISTRATION In the event of an emergency, potassium iodide will be administered to authorized personnel if the projected dose to the thyroid is likely to exceed 25 rem.

If the projected dose to the thyroid is not likely to exceed 25 rem, the issuance of potassium iodide (to authorized personnel) is at the discretion of the Health Physics director and/or the rad / con waste manager.

6.0 THYROID DJSE CALCULATIONS The dose to the thyroid from airborne concentrations of radiciodine may be calculated as follows.

l 6.1 Inhaled Conversion Factors. rads /uCi:

i I-131 1.480 rads / Ci j

I-132 0.054 rads / Ci '

1-133 0.400 rads / Ci I-134 0.025 rads /pCi  :

I-135 0.124 rads /pCi  !

1 1

6.2 Breathine Ratej 6.2.1 Assume 1.25E06 cc/ hour (= 3.47E-04 m3/sec.) for short exposure times or exposures while working.

l 1

6.2.2 3 Assume 8.35E05 cc/ hour (= 2.32E-04 m /sec.) for long exposure times (in excess of a single day).

1 6.3 If the concentration of each iodine isotope is not known. conservatively use the dose factor for I-131, given above, as illustrated in the example in Step 6.5.

l Page 2 of 4 REFERENCE USE

POINT BEACH NUCLEAR PLANT EPIP 5.2

• * [' ** I EMERGENCY PLAN IMPLEMENTING l NNSR PROCEDURES Revision 8 April 9,1996 RADIOIODINE BLOCIGNG AND THYROID DOSE ACCOUNTING 6.4 The total amount of radiciodine inhaled in pCi is calculated by multiplying the average airborne concentration in pCi/cc by the breathing rate in cc/ hour by the total time of exposure in hours. The thyroid dose in rads is then calculated by multiplying the total amount in Ci by rads /pCi in the above table.

6.5 E2ampjg Gross Iodine = 5.4E-07 Ci/cc in air Breathing Rate = 1.25E06 cc/ hour Expected Exposure Time = 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />

, I-131 rads / Ci = 1.48 Calculation:

l (5.4E-07 Ci/cc) (1.25E06 cc/ hour) (1.48 rads / Ci) (1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />)

= 0.999 rads Thyroid Dose

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7.0 DQSE ACCOUNTABILITY FOR EXPOSURES TO AIRBORNE RADIOIODINE 7.1 It is imperative that accurate exposure times and radiciodine concentrations encountered be maintained for each individual's exposure to an airborne radiciodine environment for dose calcuhtion purposes.

7.2 The following minimum information should be documented for each exposure.

7.2.1 Date and time 7.2.2 Names of individuals involved 7.2.3 Duration of exposure 7.2.4 Concentrations of airborne radiciodine

, 7.2.5 Reference to specific analysis by sample number or manner in which -

concentration of airborne radiciodine was derived.

l Page 3 of 4 REFERENCE USE v ,

y" , POINT BEACH NUCLEAR PLANT EPIP 5.2

• • -  % ~

EMERGENCY PLAN IMPLEMENTING l NNSR PROCEDURES Revision 8 April 9,1996

_ RADIOIODINE BLOCKING AND THYROID DOSE ACCOUNTING

/< ATTACHMENT A This attachment is furnished for information only. The administration of potassiurn will be as stated l in Procedure EPIP 5.2.

Panent Pacnage anaert rer HOW POTASSIUM IODIDE WORKS Certain forme ofio6ne help your tnyroid gland work nght.

Most people ger rSe nodine they need from fooca. hke iodized salt j or Sab. He thed can " store" or hold ordy a certain amount of  !

nodine.

THYRO-BLOCV' i' TABLETS In a radiation emergency ro6oactive iodme may be reluned in (POTASSit)M IODIDE TA81ETS. USP) the air. Dis matenal may be breathed or swallotved. It may enter the thyroid gland and damage it The damage would uwonouncoc poo. TASS +um EYE on<tred) orobably not show staelf for years. Children are most likely ta (abbrevisaed. KI) have thyrmddamage if you taka potaarum iodada, at wsU fdl up your thyroid giand. I Than reduces the chance that harmful radioacuve sodine will i TAKE POTASS1UM IODIDE ONLY WHEN PUBLIC enter the thyroid gland HEALTH OFFICIALS TELL YOU. IN A RADIATION l EMEROENCY. RADIOACTIVE IODINE COULD BE WHO SHOULD NOT TAKE POTASSIUM IODIDE RELEASED INTO THE AIR. POTASSIUM IODIDE (A The only people who should not take potassium iodide are FORM OF IODINE) CAN ID:U' PROTECT YOU. P*ople who know they are allergic to iodade. You may take Potasesum iodsde even af you ere takang medacines for a thyroid IF YOU ARE TOLD TO TAKE THIS MEDICINE, TAKE IT P'roblem (for example, a thyroid hormone or antithyroid drug).

ONE TIME EVERY 24 HOURS. DO NOT TAKE IT MORE t regnant and nursin awomen and babies and children may also OTTEN. MORE WILL NOT HELP YOU AND MAY take ttus dmg-INCREASE THE RISK OF SIDE EFFECTS. DO NOT TAKE Tills DRUG !! YOU KNOW YOU ARE ALLERGIC TO HOW ANO WHEN TO TAKE VOTASS8UM 800lOE IODIDE. (SEE SIDE EFFEC"IS BELOW.) Potassium iodide should be taken as soon c3 possible after ,

Pubhc bealth ofLeials tau you You sheuld take one dose ewry I 34 hours3.935185e-4 days <br />0.00944 hours <br />5.621693e-5 weeks <br />1.2937e-5 months <br />. More will not help you because the thyrmd can " hold"

% ) only hauted amounts ofiod no. Larger doaca will increase the risk of side eSecta. You will probably be told not to take the drug for more than 10 days. 1 INDICATIONS $1DE EFFECTS THYROID BLOCKING IN A RADIATION EMERGENCY Usually, side effects of potassium sodide happen when people ONLY. taka hsgher doses for a long time. You should be careful not to ,

s take mon than the remmmended dose or take at for longer than DIRECTIONS FOR USE you are told Side eMeets are unlikely because of the ion dose  ;

Use only as airected by State or local pubbe health authontaes and the short une you will be talung the drug 1 m the event of a radiation emergency.

Pouable side enects include skin rashes, swelhng of the sahvary Tablets ADUL AND Cit!LDREN 1 YEAR OF gianos and "soAsm"(metalhe taste, burtung mouth and throat.

AGE OR OLDER. One (1) tablet once e $$pN,7AI*P,[ms of a head cold, and sometames day. Crush for small children.

BABIES UNDER 1 YEAR OF AGE.

One. half 0/2) tablet once a day. Crush A few people have en allergic reaction with more serious h symptoms Dese could be fever and Joir.t pe nn, or swethng nr parts of the face and body and at times severe shortness of Dreath recuartng unmediate medecal attenuan.

Take for 10 days unless directed otherwise by State or local public health authenusa Taktrig lodida may rarely cause overactivity of the th> road gland. undersetmt* of the thyrose gland or enlargement of the Store at centroCed room tamparsturv betwun 16' and 30*C (59 myrmd gland pr) to 86*F). Keep container oghtly closed and protact from hght.

WHAT TO DO IF SIDE EFFECTS OCCUR H the side eGecta are severe or if you have an allergic reaction.

WARNING stop takang potassium iodide. Then. af possible, call a doctor or Posassasan sadade shodd not be used by people allergte to sodida pubbe health authonty for tnstructnons.

Keep out of the reach of children. In case of overdose or allergic reactson, cordact a physician or the public health authonty. HOW SUPPLIED THYRO. BLOCKS TABLETS tPotassium todade Tablets. USP)

DESCRIPTION are wtute. round Lebiets. one side awed other side debossed Each white, round, scored, monogTammed THYRO-DLOCK8 LLA each con TABLET contains 130 mg of potassium sodide. Other N2 in ng30 po esgum iodide.

ingredienta: mapesium ateerste. microcrystalhne cellulose, sibca gel, and sodium thiosulfate WALLACE LABORATORIES Dmswon of CARTER

• alt. ACE. INC.

Craneury. New Jersey 00512 IN44y2 03 Rey, $/94 s

.! Page 4 of 4 REFERENCE USE