ML17202U779
| ML17202U779 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 08/03/1990 |
| From: | Davis A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Reed C COMMONWEALTH EDISON CO. |
| References | |
| CAL-RIII-90-14, NUDOCS 9008090120 | |
| Download: ML17202U779 (2) | |
Text
UNITED STATES a
-CLEAR REGULATORY COMMISSION 9 REGION Ill 799 ROOSEVELT ROAD GLEN ELLYN, ILLINOIS 60137 AUG o 3 1990 CONFIRMATORY ACTION LETTER
- Docket No.*50-237 Commonwealth Edison Company ATTN:
Mr. Cordell Reed Senior Vice President Opus West II I 1400 Opus Place Downers Grove, Ii 60515 Gentlemen:
CAL-RI II-90-014 This letter confirms the telephone conversation between E. G. Greenman of thi~
office and D. Galle of your staff on August 3, 1990, related to the Target Rock Safety Relief Valve problem leading to the manual scram which occurred on August 2, 1990, at Dresden Unit 2.
At that time, operators manually scrammed.
the reactor after all attempts to close the Target Rock Safety Relief Valve failed.
Following the reactor scram, the torus bulk water temperature reached a temperature of 122 degrees f, and during the reactor cooldown the maximum permissible cooldown rate of 100 degrees F per hour was exceeded.
Subsequent to the reactor scram, you made a drywell entry on August 3, 1990, -
at 2:00 a.m. (CDT), and discovered a loose terminal box supported only by electrical wires containing electrical leads leading to _several valve components, including a separated conduit.
With regard to this event we understand that you either have completed or will:
- 1.
Quarantine the electrical equipment as *identified above unti.1 such time as NRC Region III has had an opportunity to view the equipment and assess*its condition. This equipment was subsequently verbally released for trouble-shooting and repair on August 3, 1990.
- 2.
Provide the results of the analysis of the effect of the cooldown rate that the reactor primary system experienced as a result of the* therma 1 transient conditions experienced on August 2, 1990.
Your analysis should discuss any long term consequences of the temperature transient and* it.s duration.
- 3.
Provide the results of the analysis of the high temperature reached in the torus (suppression pool). Your analysis should discuss any long term consequences of the temperature transient and its duration.
- 4.
Provide a root cause analysis of the electrical equipment found in a degr.aded condition as observed on the August 3, 1990, drywell
. entry.
CONFIRMATORY ACTION LETTER
(-
Commonwealth Edison Company CONFIRMATORY ACTION LETTER CAL-RIII-90-014
- 5.
- Conduct a full investigation of the failed valve for a root cause analysis including a review of the maintenance history on this valve.
- 6.
Submit to NRC Region III a formal report of your findings and.conclusions including the root cause analysis of the valve failure within' 30 days of receipt of this letter.
We also under~tand.that startup of Unit 2 wiil not occur wiihout concurrence of the Regional Administrator or 'his designee~
Issuance of this Confirmatory Action Letter does not preclude the issuance of an order requiring implementation of the above commitments~
None of the actions specified herein should be construed to take precedence over actions which y~u feel necessary to ensure *plant and personnel safety.
Please let i.Js know immediately if your understanding cfiffers from that set but above.
cc:* D. Galle, Vice President - BWR Operations T. Kovach, Nuclear Licensing Nanager E. D. Eenigenburg, Station Manager
.. DCD/OCB-(RIDS).
Licensing Fee Management Branch Resident Inspectors LaSalle,
. Dresden, Quad Ci~ies Richard Hubbard J. W. Mccaffrey, Chief, Public Utilities Division*
Sincerely, A. Bert Davis.
Regional Administrator Robert Newmann, Office of Public Counsel, State of Illinois Center J~ M. Talyor, EDO J. Ljeberman, OE J. Sniezek, DEDR H. L. Thompson, OEDO J. W. Clifford, OEDO J. R. Goldberg, OGC J. G. Partlow, NRR