ML19256C991
| ML19256C991 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 06/12/1979 |
| From: | Bryan S, Klingler G, Nolan F NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | |
| References | |
| PNO-79-151, NUDOCS 7910150826 | |
| Download: ML19256C991 (1) | |
Text
PRELIMINARY NOTIFICATION June 12, 1979 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-79-151 This preliminary notification constitutes EARLY notice of an event of POSSIBLE safety or public interest significance.
The information presented is as initially received withcut verification or evaluation and is basically all that is known by IE staff on this date.
Facility:
Consumers Power Company, Big. Rock Point (DN 50-155) Charlevoix, Michigan
Subject:
REACTOR COOLANT PRESSURE B0UNDARY LEAK (REFERENCE PN0-79-90 The licensee reported to RIII that a special nitrogen pressure test of control rod drive thimble F-2 revealed that the leak is in the weld connectin;; the thimble to the inside surface of the reactor pressure vessel.
A special adaptor was used to apply approximately 100 porads of nitrogen pressure to the junction of the CRD thimble and the outside surface of the reactor pressure vessel.
This resulted in a stream of bubbles emitting from the above mentioned weld.
The core was defueled earlier during this leak location effort.
The reactor vessel is maintained full of water for shielding purposes.
Concurrent with the above efforts while the reactor is defueled, the licensee is investigating vibrational noises reported in the area of the inlet diffuser plates.
Removal of other core baffles is required to examine the inlet diffuser plates.
These efforts are in progress.
Initial findings reveal that two of the three bolts holding one inlet diffuser in place were loose.
Repair methods are being evaluated.
The State of Michigan was notified.
The licensee and the NRC do not intend to issue a press release at this time.
This inforration was reported to an NRC inspector at the site on June 11, 1979, and is current as of 9:00 a.m., June 12, 1979.
Contact:
G. Klingler, IE x28019, F. Nolan, IE x28019; S. Bryan, IE x28019 Distribution:
Transmitted H St L1'.sd Chairman Hendrie Commissioner Bradford S. J. Chilk, SECY Commissioner Kennedy Commissioner Ahearne C. C. Kammerer, CA Commissioner Gilinsky ACRS (For Distribution)
Transmitted:
MNBB 4'G P. Bldg %;37 %
V. Stello, IE L. V. Gossick, EDO H. R. Denton, NRR Region E 7 tT6 c/
H. L. Ornstein, ED0 R. C. DeYoung, NRR
/G J. J. Fouchard, PA R. J. Mattson, NRR NRR (MAIL)
N. M. Haller, MPA R. S. Boyd,f 6[e SS Bldg %:V J. Cummings, 0IA R. G. Ryan, OSP H. K. Shapar, ELD W. J. DTrcks, NMSS R. Minogue, SD S. Levine, RES 1450 1y2 PRELIMINARY NOTIFICATION 1910150 h b