ML19263D859
| ML19263D859 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 04/08/1979 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| References | |
| NUDOCS 7904130345 | |
| Download: ML19263D859 (1) | |
Text
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NUCLEAR REGULATORY COMMISSION hs h
REGION V Os' SUITC 202, W ALNUT CREEK PLAZA
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WALNUT CREEK, C ALIFORNI A 94596 April 8, 1979 Docket flo. 50-312 Sacramento Municipal Utility District P. O. Box 15830 Sacramento, California 95813 Attention:
Mr. John J. Mattimoe Assistant General Manager Gentlemen:
In accordance with our letter dated April 1,1979 transmitting Bulletin 79-05, we are enclosing Preliminary tiotification 79-67tl.
Sincerely, oWm Ed!~
c R. H. Engelken Director Enclosure Pfl0-79-67tl cc w/ enclosure:
5 R. J. Rodriguez, SMUD f
L. G. Schwieger, SMUD l
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E g c.:. w m IleiEDIATE PRELIMlhARY NOTIFICATION April 8,1979 PRELIMINARY NOTIFICATION OF EVENT OR UNU5UAL OCCURRENCE--PNO-79-67N This preliminarv notification constit.utes summary information of an ovent of safety or public interest signi ficance.
The infornation presented is a surr, mary of iTttornation as of 7:00 a.m. nn 4/8/79, Facilitv: Three H11e Island Unit 2 Middletown, Pennsylvania (DN 50-320) subiect:
NUCLEAR INCIDENT AT 1HREE MILE ISLAND plant Status Bulk coolant inlet and outlet temperatures are about 281 degrees F.
The average core thermocouple temperature is about 299 degrees F, and the higher thermocouple reading (SH) is about 442 degrees F.
At approximately 1955 hours0.0226 days <br />0.543 hours <br />0.00323 weeks <br />7.438775e-4 months <br />, April 7, the licensee began lowering reactor coolant system pressure in 50 psi increments at a maxitnuta rate of 5 psi por minute.
This will continue until pressure reaches 500 psi, providing a 100 psi safety margin above saturation for the current temperature of the highest reading thermocouple.
This is a step toward cold shutdown and includes degasification to prevent bubble formation as pressure and temperatures decrease.
During the initial pressure decrease to 700 psi, the auxiliary building stack monitors showed an increase of a factor of 10 at 2213 hours0.0256 days <br />0.615 hours <br />0.00366 weeks <br />8.420465e-4 months <br />, April 7.
Later information indicates that about 1400 gallons of borated water were 6ddad to the makeup tank during the initial pressure reduction, causing some go; to leak from the vent header.
The ARMS helicepter reported a slight incraase in readings downwind (south) of the site.
Pressure was held steady for a short period and the auxiliary stack monitors decreased to the original readings, During the rollowing pressure cycles there have i-been no increases in the radiation readings.
Hydrogen concentration in containment is about 1.9%.
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.a At 2130 hours0.0247 days <br />0.592 hours <br />0.00352 weeks <br />8.10465e-4 months <br /> PST, April 7, airlifting of backup charcoal filters for the auxiliary building stack was initiated from Pasco, WA, to Harrisburg, PA.
The Unit 2 miscellanw.s waste t in preparation for puu. ping the a was stopp&d late on April 7 when DUPLICATE DOCUMENT Entire docament previously entered into system under:
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