ML13319B013
| ML13319B013 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 04/02/1979 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Johari Moore SOUTHERN CALIFORNIA EDISON CO. |
| References | |
| NUDOCS 7904110320 | |
| Download: ML13319B013 (5) | |
Text
SREC UNITED STATES 0 NUCLEAR REGULATORY COMMISSION REGION V IN-KV IG7
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SUITE 202, WALNUT CREEK PLAZA 1990 N. CALIFORNIA BOULEVARD WALNUT CREEK. CALIFORNIA 94596 April 2, 1979 Docket No. 50-206 Southern California Edison Company P. 0. Box 800 2244 Walnut Grove Avenue Rosemead, California 91770 Attention: Mr. J. B. Moore Vice President Gentl emen:
In accordance with our letter dated April 1, 1979 transmitting Bulletin 79-05, we are enclosing Preliminary Notification 79-67H.
Sincerely, R. H. Engelken Director Enclosure PNO 67H cc w/enclosure:
J. M. Curran, SCE J. T. Head, SCE 7 904 110 3 e
IMEDIATE PRELIMIRARY NOTIFICATION April 2 1979 17 PRELIMIUARY NOTIFICATION OF CVENT OR UNUSUAL OCCURRNC --PHO-79-67H This ioralmiriary notification CoP.ttUtCS SU r'ary inforinatiofl of an. event
... 4Z of safety or pubilic 11.;L:,2S L teaJest s fgnifcance.'
The i nform at,on. presented i s a SM~ratxof. in-formatiofl as of 1Z nooin on 4/79.T Facility: Three 1iile Island Unit 2 Middletown, Pennsylvania (ON 50-320)
S Ct:
NUCLEAR INCIDEWT AT THREE MILE ISLAND Plant Status Reactor pressure is being held at about 1000 psi Incore thermocouples coflilC osnwadcraei fuel channel terpratures, with all Vilasure-nts bal &- about 475 degrees F. Bulk core inlet and outlet te-A-peratures are 2^80 dagra-es :F.
At I I p.m., April1 1, a Contairme n t air sample indicated 2.3% hydrogen.
Further analyses and consultations with experts has led to the develop ment of a strong concensus that the net oxygen gensration rate inside the noncoRdnsible bubble in 'the reactor is much less than originally atively estimated.
Also measurerenits at the plant appear to indicate that the voluse of gases within the bubble is baing signifr cantly reduced.
Further dev10pments are being closely followed to confims these favorable indications.
Action on Othar Facilities The Threa Mile Island Unit 2 (TIHI-2) pressurized -ater ri-eactor was supplied by Babcock & Wilcox (n,4).
All utilities with an operating B&W rector ware sent an NRC Bulletin yesterday to provide them with inforMa tion about the TiI-2 incident; require a prompt review of their plant Sconditions-and to effect action to prevent such an incident. NC inspectors are being sent to each licensed R&W reactor to provide increased inspection coverage.
Additional reactor shutdowns or power reductions are not being required by the NRC at this time.
Envirmei-ntal Status Thirty-seven therroluminescent dosimetry (TLD) stations were established by the Nc at distances fromr aboiut one mile to about 12 miles from the plant. Multiple dosimeters are placed at each location -
one will be CONTINUED 904110036
Continued April 2, 1979 Page 2 PO-79-67H left in place for a cumulative dose measurement; another is pulled and replaced each day.
TLD's collected on April 1, 1979 indicated the follcwlng dose rates in populated areas; Location Dose Rate (H11ircentgens per Hour)
Middletown) 0.044 Goldsboro 0.13 Goldsboro 0.040 Lewisberry 0.053 Pleasant Grove 0.041 York Haven 0.074 Conewago Falls
- 0. 044 Eigsville 0.053 The highest dosimeter reading was recorded at a location m
mile ENE of the plant.
The average dose. rate at this location was 1.1 ni.liroentgen per hour.
For comparison purposes, the licensee's environmental report for 1977 when one unit was operating, indicated that the average dose rate at offsite stations located within three rmiles of the plant was 0.007 rR/hr.
Calculations using tha TD data indicate a population dose of approxi m'ately 200 man-reas for the 24-hour period.
This means there was an avarage radiation dose of about 0.3 millirems. per person in the population within a 20-oill1 radius of the plant.
ARM's flights were continued at three-hour intervals on April I, and 2, 1979.
The plumie readings were essentially the same for all the flights.
Direction of the plume varied from SW to W.
The maximum lsvel at one mile from the plant was about 3 mR/hr at an altitude of 500 feet.
At three miles, the levels were from 0.1 to 0.5 mR/hr.
Offsite ground level surveys taken between 11:00 a.m. April 1, and 4:30 a.m. April 2, on both sides of the river in a southerly direction g naeally showed levels of 0.01 to 0.04 mR/hr.
Nine milk sampTes collected and analyzed by the State of Penhsylvania on April 1 showed no detectabl radiolodine.
The licensee reported results from 5 milk samples taken fro". four loca tions around the plant collected the evening of March 30, 1979.
The samples included one samiple of goat's milk and four samples of cow's milk.
The highest level was reported for the goat's milk and was 41 picocuries per liter (pCi/1.).
. The highest level in cow's milk was 8.4 pCi/.
The NRC has estimated. the thyroid dose toa child drinking milk with concentra tions of radlolodine at 41 pCi/l to be about 0.2 milliren per day.
The thyroid dose to an adult would be about.0,07 millirem per day.
Each of.
these samples indicated levels slightly above normal background levels for radiocdine.
CONTI UED
Continued April 2, 1979 Page 3 PNO-79-67H The Bureau of Radi6lcgical Health, HEW, also reported identifying radio iodine in six samples of milk collected on March 31, 1979 from four locations around the plant.
Analyses.of the samples identified near background levels of radioiodine.
The levels ranged from the! minimum detectable limit to about 40 pCi/l.
For comparison, the licensee's environmental report for 1977 showed observations of 0.74 to 31 pCi/1 of 1-131 in rmilk throughout the year previous to the incident.
At 12,000 pCi/1, the U.S. DepartmLent of Health, Education, and Welfare recommlends placing dairy herds on stored feed.
Local hards are already on stored feed.
Contact; DThompson, IE x28487 NCMoseley, IE x28160 Distribution:
Trans itted H S tfX fan endri e Co miis r Bradford S. J. Chilk, SECY Commissioneir Kennedy Commissioner Ahearne C. C. Karpderer, CA Com-issioner Gilinsky (For Distribution)
Tran smit ed:
NN0 B P. Bldg J. G. Davis, XE L. V. Gossick, EDO H. R. Denton, NRR Region I H. L. Ornstein, ED0 R. C. DeYoung, NRR Region II J. J. Fouchard, PA R. J. Mattson, NRR Region III N. M. Haller, NPA V. Stello, NRR Region IV R. G. Ryan, OSP R. S. Boy NRR n V H. K. Shapar, ELD SS Bldg W. J. Dircks, NHSS J. J CaiDings, 01A LeR.
Minogua, SD White House Situation Room
- ~
(Handcarry
)
EPA FOA/8fF DOE/EOC____
FA FDAA Radiation Dose Rate Hap IMXMEDIATE PRELIMINARY NOTIFICATION
Attachrent 1' NRC THEP MOLUMINESCENT DOSIMETER (TLD)
Numbers are cumulative radiation dose in millirem over a 23 hour2.662037e-4 days <br />0.00639 hours <br />3.80291e-5 weeks <br />8.7515e-6 months <br /> period during March 31 and April 1, 1979.
The highest dose (25-8 mrem) was measured at 0.5 miles ENE of the plant; the next highest (10+/-2 m-em) at 1 mile SSE.
Palyra detown
'--A o "mil thto n A FPX sCAL 10