ML19199A310
| ML19199A310 | |
| Person / Time | |
|---|---|
| Issue date: | 02/28/1979 |
| From: | Hoyle J NRC OFFICE OF THE SECRETARY (SECY) |
| To: | |
| References | |
| ACRS-MA-0711, ACRS-MA-711, NUDOCS 7904120301 | |
| Download: ML19199A310 (5) | |
Text
gggW IMMEDIATE PRELIMINARY NOTIFICATION April d. 1979 PRELIMINARY NOT UICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-79-67L This oreliminary notification constitutes summary information of an event of sarety or puolic interest s'anificence.
lhe information oresented in a summary of informat. ion as o{ 7:00 a.m. on 4/6/79.
Facility: Three Mile Island Unit 2 Middletown, Pennsylvania (DN 50-320)
Subject:
NUCLEAR INCIDENT AT THREE MILE ISLAND Plant Status Reactor pressure is about l075 psi with bulk core coolant inlet and cutlet temperatures at about 285 degrees F.
Core thermocouple readings are relatively unchanged and indicate a maximum temperature of 448 degrees F, well below saturation temperature for the present reactor pressure.
Three thermocouple readings remain above 400 degrees F.
Thirty thermo-couples are being monitored.
Containment atmosphere measurements indicate less than 2% hydrogen, One hydrogen recombiner is in operation, with the second unit on standby, A Heise pressure gauge, installed to provide an alternate method if monitoring pressurizer level, has been unsatisfactorily pressure tested.
(Boron crystals indicate leakage f rom an eTbow in thq bypass line around the sample cooler.)
Plans to vent Make-Up Tank (MUT) and one of the Waste Gas Decay Tanks (WGDT) gases to containment have been approved by the NRC, Waste Gas Decay Tank "A" venting to the containment was started at approximately 0545 on April 6, 1979.
Venting was terminated at 0630 following an approximately ten-fold increase in radiation levels detected by the auxiliary building exheust monitor.
Environmental Status Periodic ground level radiation surveys performed on April 5,1979 by the HRC survey teams on the east and west sines of the Susquehanna River from a distance of 4 miles north to 4 miles south of TM1 detected radiation levels averaging less than 0.01 mR/hr on the west side and from 0.01 to 0.15 mR/hr on the east sice.
Prevalent wind direction during the day was from the west-northwest.
!^
1.0 VQR 790412060(
/'
(
s Continued April 6, 1979 Page 2 PNO-79-67L ARMS surveys were performed on April 5, 1979 at 0500, 0950, 1430, 1515, 1649, and 2120 hours0.0245 days <br />0.589 hours <br />0.00351 weeks <br />8.0666e-4 months <br />.
The flights identified the plume in the sector 110 to 130.
The maximum radiation levels were detected during the 0950 flight during which levels of 0.3 mR/hr were measured at 1 mile.
Between 3 and 10 miles, the measured levels were from 0.03 to 0.05 mR/hr.
The State of Pennsylvania reported data on milk, water, precipitation and grass samples.
Analysis of ten milk samples collected on April 4 and 5 detected no radiciodine above the minimum oetectable activity (MDA).
Also, the results of analysis of water samples collected from five cities surrounding TMI from March 31, 1979 to April 4, 1979 detected no levels of iodine above the MDA, as did analysis of precipitation and grass samples for April 2 and 4.
Dose rates in populated areas as measured by NRC thermoluminescent dosi-eters (TL0s) showed only minor changes from the previous day.
Minor fluctuations are expected at these low dose rates.
Ten additional TLD stations at area schools were established on April 5 (making a total of 47 stations).
Following are the exposure rates for previously reported locations:
Dose Rate (Milliroentgens per Hour) 4/1/79 4/2/79 4/3/79 4/4/79 4/5/79 Falmouth 0.15 0.01 0.20 0.04 0.02 Middletown 0.04 0.01 0.02 0.01 0.01 Goldsboro 0.13 0.05 0.07 0.07 0.05 Goldsboro 0.04 0.02 0.05 0.02 0.03 Lewisberry 0.05 0.02 0.04 0.03 0.02 Pleasant Grove 0.04 0.02 0.05 0.01 0.01
~
York Haven 0.07 0.02 0.10 0.05 0.01 Conewago Heights 0.04 0.02 0.07 0.02 0.01 Emigsville 0.05 0.02 0.07 0.02 0.02 Population Exoosure Estimates e
Representatives from NRC, EPA and HEW have made estimates of the radiation doses to the public around TMI based primarily on TLD data.
The calculated population dose increment for 4/3/79 to 4/4/79 is 70 man-rems.
The total cumulative, 50 mile radius population dose since 3/28/79 is estimated to be 2100 man rems with an average dose to an individual of 1.1 millirems.
The estimated maximum dose to an individual offsite (hypothetical, ton-tinuously present 0.5 mile NE of plant) is estimated to be less than 100 millirem.
y') !'n??
=
l Continued April 6, 1979 Page 3 PNO-79-67L Industrial Waste Treatment System (IWTS)
Industrial waste discharge (other than sewage) began about 3 a.m.
4/6/79 at an average rate of 100 Qpm with Iodine 131 radioactivity of 2.3 x 10-5 microcuries per milliliter into the 58,000 gpm cooling tower discharge to the river.
The Unit 1 waste evaporatt. condensate storage tank is also being discharged.
The licensee has calculated the release to the river to be about two-thirds the HPC for continuous discharge of Iodine 131 from both units.
The discharge from the Unit 2 Industrial waste Treatment System was stopped at approximately 0400 on 4/6/79 to collect and analyze a sample.
Other Information IE Bulletin 79-05A was issued on April 5,1979 and required additional actions by Babec,ck and Wilcox power reactor facilities with a operating license.
Contact:
Distribution:
Transmitted H St / N O U Chairman H2 drie Commiss ione7Bradford S. J. Chilk, SECY Commissioner Ke^nedy Commissioner Ahearne C. C. Xammerer, CA Commissioner Gi.insky (For Distribution)
MNBB /2'/Op P. Bldg dC/[-
J. G. Davis. IE Transmitted:
L. V. Gossick, ED0 '
H. R. Ddnton, NRR Region I H. L. Ornstein, EDO R. C. DeYoung, NRR Region II //> t n J. J. Fouchard, PA R. J. Mattson, NRR Region III N. M. Haller, MPA V. Stello, NRR Region IV R. G. Ryan, OSD R. S. Boyd, NRR Region V H. K. Shapar, ELD SS Bldg K re.Cl4'67 (MAIL)
W. J. Oircks, NMSS J. J. Cummings, CIA S. Levine, RES R. Minogue, SD IE (THI) Site //1344.nt(Provide copy to STATE)
Wnite House Situatiorf Foom _
' EPA FDA/5RH 00E/E0C FDDA/ FEMA BRP (State of PA)
DCPA HEW Handcarry (FAA)
IMMEDIATE M ' ' b3 PRELIMINARY NOTIFICATION