ML17297B929

PNO-79-67V:summary of Info Re Nuclear Incident as of 790415. Describes Plant & Environ Status

ML17297B929
Person / Time
Site:	Crane
Issue date:	04/15/1979
From:	Gower G, Thompson D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
To:
References
PNO-79-067V, PNO-79-67V, NUDOCS 7904250013
Download: ML17297B929 (6)

Text

> ~

Sbsv>

,v >(T~

~

'(V>

9.l 10~

W '-r BvEll llPj ys )979 (av, F>EClo>/ r

~fv'~PZCnp;~ <

OTFog~p~~( ~

/

(Xp IMMEDIATE PRELIMINARY NOTIFICATION aev 4$Jb v>

r(')

'I v v% 's>

'&ye.'>

>r>(,Z.,'.

Ieie'. '

• 1 (q'

~

ffH';

~

QTI:(*..

~F>Vga'VS eb 'vvs

'ct 8'~f>'vsse(

~ (

>~m$ V('

>$4~)"

'~

L77+'s.'

>>V ~

.((>fib v ~'

V

'"~

~

V%NN

~

't

')4(,

~

~ A.iv-i (1

( V

.V

>w w~~~'~fi V~

April 15, 1979 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE' PNO-79-'67V j,f"., ='.

This relfmfnar notification constitutes sugar information o'f an event of safet or ublic interest si nificance.

The info(>sat~ion resented is a sunna}.

o informat on as of 7:00 a.m.

on A ril 15, 1979.

Facility:

Three Hfle Island Unit 2 Hiddletown, Pennsyl vania (DN50-320)

~Sub'ect:.

NUCLEAR INCIDENT AT THREE NILE ISLAND Plant.Status:

ae

-'qf +59k

">s As of 0600 oh April 15, 1979, primary coolant temperature had stabi1ized at approximately 250 degrees F.

Four of the incore thermocouple readings

'mafn-above 300 degrees F with the highest at 348 degrees F.

The hydrogen recombiner that failed on April 13 has been repaired and is in the process of being restored to service.

~

The staff has completed a preliminary evaluation of TMI-2 fuel damage.

Examinations of data from core thermocouples, incore detectors and excore ion chambers, and analyses of core parameters such as primary coolant. pressure for the first fifteen hours of the transfent show

> several periods of significant core uncovery.

These were time periods-durfng which portions of the fuel elements were cooled by steam rather than pressurized water which fs the normal cooling method.

It was dur'ing these periods of deficient coo1ing that extensive damage to the fuel elements occurred.

This damage occurred primarily by oxidation of the fuel cladding and other zirconium alloy components, which were embrittled'and lost structural integrity in some regions of the core.

Estimates of the extent of'amage were calculated from fission product and hydrogen releases inside the plant and radiochemical analysis of the reactor coolant water.

The analyses indicate that

significant cladding oxidation occurred in the upper regions of the core and most fuel rods have sere damage.

The core geometry in the upper regions of the core, especially nea'r. the center, is. believed to be severely distorted due to loss of fuel cladding integrity in that region.

However, the lower and peripheral portions of the core are believed to have retained their basic structural integrity.

The highest fuel temperature during the transient is estimated by these damage mechanism analyses to be well below the 5100 degrees F fuel melting point.

Previous results of radiochemical analyses of primary coolant samples support this conclusion of little or no fuel melting.

V V

s ~

V >>>

'I VV sgess,>>

M>(V

~

pre".i'HNEOIATE PRELIMINARY NOTIFICATION 7904a5oo z3

~ <W I I

et<'roon C

OI gA

'I a

~~i TjT.~

1V'~Rff".

-<s I~~~&f<<'e'

~t

~.';IIO.

i

~

wb~'>4

'-tgl~Vr <-

<-TfSj\\I

~~m~h.;:

,s.

4 ~>~:t-'.

aLa s

~~aa3,

'ats rl'S

~~~~ fr.r FjV~4",%,

~

fi~4~$V~(s

'ontinued Page 2

April '15, 1979

'PNO-79-67V Environmental Status:

T Offsite radiation levels identified by HRC survey teams were consistent with normal background levels (0.02 mR/hr maximum).

The results were obtained from routine surveys performed on the east and west sides of the Susquehanna River at distances up to five miles north and south of the site.

c By 9:30 a.ro..on April 14, 1979, 375 local residents were scanned with the whole body counter located in Hiddletown.

Scan results indicate no radiation levels above normal body levels.

The following Aerial Measuring System surveys were conducted on April 14, Hind speed was variable.

The principle isotope is Ãe-133.

TTiime Max. Radiation Levei Sector Distance from Site 1138 - 1221 0.04 mR/hr

'70

=-

1000 feet a

The NRC took a 24-hour air sample near the observation center starting at 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br /> on April '}3;, 1979.

The results indicated less than 3.0 picocuries per cubic meter of iodine-131.

The 10 CFR 20 limit for iodine-131 is 100 picacuries per cubic meter.

Dose rat'es.(47 locations) as measured by NRC thermbluminescent dosimeters for the past 24-hour period of April 14 are near expected natural'ackground levels.

4 Water

.4 Vegetation 4 Air (3 ground level and 1 helicopter)

CONTINUED I/MEDIATE PRELIMINARY NOTIFICATION A pressurized primary coolant'sample was taken April 13, 1979.

The six individuals invOlved received a total radiation dose of 800 mrem.,

The highest individual dose was 270 mrem.

During the period of 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br /> an April 13 to 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br /> an April 14, DOE collected and analyzed the following samples:

Number T e

I-131 HDA 7

X 10 microcuries/cubic centimeter 0.04 nanocuries/square meter microcuries/cubic centimeter

.=as

~ ~

Continued

. Page 3

Revised April 15, 1979 PNO-79-67V

,l ".-

e s S. J. Chilk, SECY C. C. Kaaeerer, CA P.Bldg H. R. Denton, NRR R,

C.

DeYoUng, NRR R. J. Nattson, NRR V. Stello, NRR R. S. Boyd, NRR SS Bldg H. J. Dsrcks, NMSS S. Levine, RES J. G. Davis, IE Region I Region Il Region IIT

~

. Cunl)ings. OIA R. Minogue, SO A1'1 water, 3 vegetation, and 1 ground level.air samples indicated less than HDA for I-13l.

One vegetation (grass) sample indicated 0.16 nanocuries/square meter I 131.

Two ground level air samples

{collected at'he same location and time side-by-side on April 13 at ll:45 a.m.) indicated I-131 levels of 9.5 picocuries per cubic meter.

)

An air sample taken by helicopter 100 meters downwind of the auxiliary building stack (within the restricted area) indi'cated an I-131 activity-

'f 119 picocuries "per cubic meter.

The 10 CFR 20'imit is 9000 picocuries per cubic meter.

The cause of thi,s increase in-radioactivity in certain environmental samples

$ s pot known but is under investigation.

It is possibl'e that.

the increase is the, result of the change-out of the charcoal filters.

4

Contact:

GCGoner I'.E x27246 DThompson, IE x28487 Distr(hut(on:

Transmitted H St dA ()

Chairman Hendrie Corani sioner B) adford Corrmissioner Kennedy Coranissioner Ahearne Commissioner Gilins I

Transmitted:

HNBB

1. Y. Seasick.

EDO

'H. L. Ornstein, EDO J. J. Fouchard, PA N. X. Hailer, (eA R. G. Ryan, OSP H. K. Shapar, ELD IE (TNI) Site (Provide copy to STATE)

Hh'lte House Situation Room

-" PDAA

'Provide copies to the Administrator and BRP ~State of PA)

DCPA HEM flic(up)

,Handcarry (FAA)

• .".JI the Operations Center)

• r 7

IHBEDIATE PRELIMINARY NOTIFICATION vrev ~

s ~