ML20091G283

Ro:On 840516,discovered Unanticipated Increase in Water Level in Steam Generator B.Caused by Steam Generator Tube Failure.Efforts Initiated to Determine Corrective Actions

ML20091G283
Person / Time
Site:	Fort Calhoun
Issue date:	05/22/1984
From:	William Jones OMAHA PUBLIC POWER DISTRICT
To:	John Miller Office of Nuclear Reactor Regulation
References
LIC-84-149, NUDOCS 8406040213
Download: ML20091G283 (2)

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Omaha Public Power District 1623 Harney Omaha. Nebraska 68102 402/536 4000 May 22, 1984 LIC-84-149 1

l Mr. James R. Miller, Chief U. S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Division of Licensing Operating Reactors Branch No. 3 Washington, D.C. 20555

Reference:

Docket No. 50-285

Dear Mr. Miller:

Steam Generator Tube Failure on May 16, 1984, at approximately 1650 hours0.0191 days <br />0.458 hours <br />0.00273 weeks <br />6.27825e-4 months <br />, while performing a hydrostatic test of the reactor coolant system, operating per-sonnel observed an unanticipated increase in the water level in "B" steam generator. The reactor coolant system was at a temper-ature of 398'F, 1800 psig, with 488'F in the pressurizer. The secondary side of the steam generator was at approximately 200 psig. The plant staff personnel determined that the most probable cause of the unexpected water level increase in the "B" steam generator was a result of a tube failure and, therefore, appropri-ate actions were taken to depressurize the reactor coolant system and the Radiological Emergency Response Plan was activated. No offsite releases of radioactivity occurred. Additional details of the incident were provided to Mr. E. G. Tourigny of your staff during telephone calls on May 17 and 18, 1984 in an effort to keep your office informed of actions taken by District personnel. In addition, Mr. L. A. Yandell was present in the control room during the initial stages of this incident.

Since the steam generator tube faflure on May 16, 1984, the Dis-trict has taken action to identify the failed tube and the cause of the tube failure. In addition, efforts have been initiated to determine appropriate corrective actions and measures in order to reduce the probability of recurrence of additional tube failures.

To date, the District has identified that one tube in the peripher-al area in "B" steam generator has a through-wall defect in the l horizontal run of the tube. A plan is presently being developed which will represent the District's actions regarding the identi-fication of the cause of the tube failure and other corrective 8406040213 840522 PDR ADOOK 05000285 /

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Mr. James R. Miller LIC-84-149 Page Two actions:which will be taken. The District plans to keep your of fice informed on these plans. Also, as requested by you in a telephone call on May 22, 1984, the District is preparing for a meeting with your staff prior to returning the plant to power oper-ation.

Sincerely,

?llb W. C., Jones Divisifn Manager Produhtion Operations WCJ/JJF: jam cc: LeBoeuf, Lamb, Leiby & MacRae 1333 New Hampshire Avenue, N.W.

Washington, D.C. 20036 Mr. E. G. Tourigny, Project Manager Mr. L. A. Yandell, Senior Resident Inspector