ML19263D873
| ML19263D873 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 04/09/1979 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| References | |
| NUDOCS 7904130374 | |
| Download: ML19263D873 (1) | |
Text
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umTED STATES t
NUCLEAR REGULATORY COMMISSION s,,
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o SUME 202. WALNUT CREEK PLAZ A U
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,o 1990 N. C ALIF OHNI A BOULEVA RD 9 *eee*
W ALNUT CREEK, CALIFORNI A 94596 9
April 9,1979
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Docket flo. 50-312 Sat ramento 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 flotification 79-67P.
Sincerely, kWL,<cG_
R. H. Engelken Director Enclosure Pfl0-79-67P cc w/ enclosure:
F R. J. Rodriguez, SMUD h
L. G. Schwieger, SMUD L
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IMMEDIATE PRELIMINARY NOTIFICATION Apri19,[1979
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PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-79-67P*
This preliminary notification constitutes summary information of an event
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of safety or public interest significance.
The information presented is a
_ summary of information as of 6:00 a.m. on 4/9/79.
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Facility: Three Nile Island Unit 2 Middletown, Pennsylvania (DN 50-320)
Subject:
NUCLEAR INCIDENT AT THREE MILE ISLAND
_P_lant Status Bulk coolant inlet and outlet temperatures are about 280 degrees F.
The v
average core thermocouple temperature is about 300 degrees F, and the highest i,'
thercoccuple reading (8H) is about 425 degrees F.
Y At approximately 0430 hours0.00498 days <br />0.119 hours <br />7.109788e-4 weeks <br />1.63615e-4 months <br />, April 9, the reactor coolant system pressure reached the 400 psig endpoint established for the second degassing evolu-tion.
At lower pressures in the 400 to 1,000 psig range, noise monitoring indicated possible presence of some gas in loop B of the reactor cooling system.
1-Noise monitoring verified re-solution of gas with time.
The cperating reactor coolant pump vibration increased to 8.5-9 mils but the level of vibration was still significantly below the limit (30 mils).
Pressure variation for degassing is continuing.
Following reduction to 400 psig,
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the licensee plans to increase pressure to the 900-1,000 psig range and a phased cooldown is under consideration as the next step.
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The licensee requested and received permission to temporarily change the 9
minimum pressurizer level to 150" from 200" to prevent high pressurizer q,
levels on pressure decreases.
4:s At approximately 1320 hours0.0153 days <br />0.367 hours <br />0.00218 weeks <br />5.0226e-4 months <br />, April 8, the reactor coolant system began to heat up.
This was due to a decrease in steam generator level.
Steam Generator A level was increased to decrease the primary temperature.
Hydrogen concentration in containment is about 1.85%.
At approximately 1942 hours0.0225 days <br />0.539 hours <br />0.00321 weeks <br />7.38931e-4 months <br /> EST, the last airplane involved in the filter airlif t lef t Pasco, WA, for Harrisburg, PA.
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A (Tne letter "0" was not used, previous issuance was PNO-79-67N)
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Continued April 9, 1979 Pace 2 CORRECT _F0_ COPY PNO-7n-r,7p ma
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ENVIRONMENTAL STATUS Offsite radiation levels identified by NRC survey teams continue to range between 0.01-0.1 mR/hr.
The results were obtained f rom routine surveys performed on the east and west side of the Susquehanna River at distances of up to 4 miles north and south of the site.
The following ARMS surveys were conducted during April 8,1979:
h MAXIMUM TIME RADIATION LEVELS LOCATION DISTANCE FROM SITE v.
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00:00-00:30 1 mR/hr sector 180 h - 1 mile
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06:00-05:20 0.3 cR/hr sector 200 1 mile (west-southwest) l.
09:00-09:50 0.03 mR/hr sector 170 1 mile (south-southeast) 18:05-18:30 0.05 mR/hr sector 275 3 miles (west-northwest) 3..
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Eight offsite air samples collected near the NRC trailer during April 1-8 indicated iodine-131 concentrations between 0.9 - 3.3 picocuries per cubic meter (pCi/m ).
The maximum permissible concentration per 10 CFR 20 3
a is 100 pCi/m,
s No new data were reported for milk, water, and vegetation samples.
Offsite dose rates as determined by NRC thermoluminescent dosimeters (TLDs)
L' indicate that present radiation lev: 1s are in close agreement with expected natural background levels.
Hinor fluctuations among individual TLDs are expected due to the limitations of the TLD systen.
Forty seven TLDs are
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presently positioned at various locations around the site.
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Dose rates (47 locations) as measured by NRC thermoluscent dosimeters have 7
ranged from 0.01 to 0.02 milliroentgens per hour for the past 24-hour periods
't of April 7 and 8.
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Continued April 9, 1979 Page 3 CORRECTED COPY PHO-79-67P ___ _
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Contact:
EJordan, IE x28180 NCMoseley IE x28160 Distribution:
Transmitted H St /
Cnairman Hendrie Co:nmTssioner Bradford S. J. Chilk, SECY Commissioner Kennedy Commissioner Ahearne C. C. Kamerer CA
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Comissioner Gilinsky (For Distribution)
Transmitted:
HNBB /8/8d 4 P. Bldg ff:o L7N J. G. Davis IE 4
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L. V. Gossick, E00 H. R. Denton, NRR Region I /d//OpY H. L. Ornstein, EDO R. C. DeYoung, NRR Region Il fd,X##7 J. J. Fouchard, PA R. J. Mattson, ilRR Region III/O;/f,p,77 il. M. Italler, NPA V. Stello, NRR Region IV /~O p/y R. G. Ryan, OSP R. S. Boyd NR3 Region V //)f,2/ Art 3
H. K. Shapar, ELD SS Bldg fo/0er#/1 (MAIL)
W. J. Dircks, NHSS J. J. Cummings, OIA S. Lovine, RES R. Minogue, SD IE (TiiI) Sita /d/624N (Provide copy to STATE)
White House Situation Room EPA f;
FDA/8RH DOE /EOC
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