ML19261C870
| ML19261C870 | |
| Person / Time | |
|---|---|
| Site: | Catawba, Perkins, Cherokee  |
| Issue date: | 04/05/1979 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Dail L DUKE POWER CO. |
| References | |
| NUDOCS 7904190169 | |
| Download: ML19261C870 (1) | |
Text
UNITED STATES
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'o, NUCLE AR REGULATORY COMMISSION REGION ll
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- p APP 0 51979 In Reply Refer To:
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( Q0-413, 5 -4'14 3 50-488750;489 50-490, 50-491 50-492, 50-493 Duke Power Company Attn:
Mr. L. C. Dail, Vice President Design Engineering P. O. Box 33189 Charlotte, North Carolina 28242 Gentlemen:
79-05-A, is f orwarded to you for information.
The enclosed IE Bulletin, No written response is required.
If you desire additional information this office.
regarding this matter, please contact Sincerely,
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h3,ames P. O'Reilly D rector
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Enclosure:
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IE Bulletin 79-05-A w/enclosuren cc w/ enc 1:
D. G. Beam, Project Manager Catawba Nucicar Station P. O. Box 223 Clover, South Carolina
?7910 J. T. Moore, Pro'ect Manager Cherokee Nuclear Station P. O. Box 422 Gaffney, South Carolina 29340 7904190 //f/
1 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, DC 20555 APRIL 5, 1979 IE Bulletin 79-05A SUCLEAR INCIDENT AT THREE MILE ISLAND - SUPPLEMENT Description of Circumstances:
issuance of IE Preliminary information received by the NRC since Bulletin 79-05 on April 1, 1979 has identified six potential human, design and eechanical failures which resulted in the core damage and radiation releases at the Three Mile Island Unit 2 nucIcar plant. The information and actions in this supplement clarify and extend the original Bulletin and transmit a preliminary chronology of the TMI accident through the first 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> (Enclosure 1).
1.
At the time of the initiating event, loss of feedwater, both of the of service.
auxiliary feedwater trains were valved out The pressurizer electromatic relief valve, which opened during 2.
failed to close when the pressure the initial pressure surge, decreased below the actuation level.
Following rapid depressurization of the pressurizer, the pressurizer 3.
level indication may have lead to erroneous inferer.ces of high level in the reactor coolant system. The pressurize-level indication apparently led the operators to prematurely terminate high pressure injection flow, even though substantial voids existed in the reactor coolant system.
does not isolate on high pressure injection Because the containment 4
initiation, the highly radioactive water from the relief (HPI) valve discharge was purped out of the containment by the automatic initiation of a transfer pump. This water entered the radioactive system in the auxiliary building where some of it waste treatment overflowed to the floor. Outgassing free this water and discharge thrcugh the auxiliary building ventilation system and filters w.s the principal source of the offsite release of radicactive nobh gases.
Subsequently, the high pressure injection system was intermit t ently 5.
inventory losses operated attempting to control primary coolant through the electromatic relief valve, apparently based on pressurizer level indication. Due to the presence of steam and or noncondensible volds elsewhere in the reactor coolant systee, this led to a further reduction in primary coolant inventory.
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