ML20081B216

Application to Amend License NPF-2,permitting one-time Tech Spec Change Re Movable in-core Detectors.Change Does Not Involve Significant Hazards Consideration

ML20081B216
Person / Time
Site:	Farley
Issue date:	10/21/1983
From:	Clayton F ALABAMA POWER CO.
To:	Varga S Office of Nuclear Reactor Regulation
Shared Package
ML20081B221	List: ML20081B216 ML20081B232
References
NUDOCS 8310270374
Download: ML20081B216 (4)

Text

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Mailing Addrosa Alagama Power Company

. 600 North 18th Street

• Post Office Box 2641 Birmingham. Alabama 35291 Telephone 205 783-6081 F. L Clayton, Jr.

CLL*Cff"' AlabamaPower the southem ermtre system October 21, 1983 l

Docket No. 50-348 _

Director, Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D.C. 20555 Attention: Mr. S. A. Varga Joseph M. Farley Nuclear Plant - Unit 1 One-Time Only Proposed '

Technical Specification Change for Movable Incore Detectors Gentlemen:

On October 13, 1983 while performing Unit 1 surveillance tests utilizing the Movable Incore Detector System (MIDS), it was determined that less than 75 percent of the detector thimbles were OPERABLE, i.e. ,

only 37 detector paths (i .e., 74%) were found operable. The remaining thirteen (13) incore detectors were not able to travel through the entire length of the incore i.histes into the reactor vessel due to mechanical thimble blockage problems. Technical Specification Section '

3.3.3.2a. requires that 75 percent (i .e., 37 1/2 rounded to 38) of the detector thimbles be OPERABLE when the MIDS is used for the following power distribution monitoring:

1. Recalibration of the excore neutron flux detection system (Technical Specification 4.3.1.1),

2. Monitoring the QUADRANT POWER TILT RATIO, (Technical Specification Sections 4.2.4.2), or

3. Measurementof[4H,Fq (Z) and Fxy (Technical Specification Sections 4.2.3.1, 4.2.2.2.a.

4.2.2.2.d.2).

A Unit i routine incore flux map was due on October 14, 1983. Flux map #130 was run on October 13, 1983 with four of five incore drive \

units operable. Acceptable data was obtained from 37 of 50 incore thimbles. Applicable surveillance interval grace periods were g determined to expire at 7:00 a.m. on October 22, 1983. Maintenance was y 8310270374 831021 cM PDR ADOCK 05000348 P PDR g, i t

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Mr. S. A. Varga October 21, 1983 U. S. Nuclear Regulatory Commission Page 2 a

scheduled to begin on the night of October 13, 1983. However, Unit I had to be shutdown on the evening of October 13, 1983 and plant conditions were unacceptable for work on the MIDS until October 19, 1983.

On October 19, 1983 fourteen containment entries (average 29 minutes due to heat) were made by 11 maintenance personnel. On October 20, 1983 fifteen containment entries (average 42 minutes due to heat) were made by 15 maintenance personnel.

! On the evening shift of October 20, 1933, flux map #131 was performed. Because of Incore Drive Unit problems only 34 of 50 thimbles were operable. At the present time, the 1C Incore Detector drive unit is inoperable with its detector not in the storage position thereby creating a high radiation field in the vicinity of the IC and ID Incore Drive Units. These high radiation fields will preclude maintenance until short lived radioisotopes decay.

1 Due to current high radiation fields, it will not be possible to correct the mechanical problems associated with the MIDS thimbles by October 22, 1983 at 7:00 a.m. CDT. Therefore, Alabama Power Company requests a one-time only revision to the Farley Unit 1 Technical Specifications as included in Attachment 1. This one-time exception would allow continued plant operation based on power distribution monitoring with 74 percent or more of the MIDS thimbles OPERABLE.

Alabama Power Company and Westinghouse have evaluated utilizing 37 versus 38 incore thimbles to perform surveillance testing and has determined that there is only a minor difference in the flux measurements contained by each configuration. As a result of these

evaluations, additional measurement uncertainties of approximately 50%

were added above those provided by Technical Specification Sections 4.2.2.2b, 4.2.3.2 and 4.2.2.3. Calculations verified that the power distribution parameters obtained under these conservative assumptions still meet the technical specification requirements for flux map #130.

i Past experience on both units has indicated concern related to the movability of these incore detectors. As a result, in June 1983 Alabama Power Company has performed an extensive evaluation of alternative corrective actions to mitigate this condition. This study

included enhanced preventative maintenance programs, design changes and entire system replacement. It was determined that enhanced preventative j maintenance was the only feasible cost effective short term corrective action, i.

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Mr. S. A. Va rga October 21, 1983 U. S. Nuclear Regulatory Commission Page 3 Prior to the last shutdown, Unit 2 exhibited several drive unit and cable problems and 10 inoperable thimbles. As a result, during the current Unit 2 refueling outage the incore flux thimbles were cleaned by forcing high pressure demineralized water at a high velocity to flush out and clean the tube bore. Compressed instrument air was used to remove the majority of the water from the tubes and provide initial air drying. Vacuum drying removed the remaining moisture.

After the thimbles were cleaned and dried, a thin uniform film of Neolube lubricant was applied along the complete length of the thimble bore. This controlled lubricant application was subsequently air-dried to smooth out the lubricating film and provide a very thin uniform thickness. A dummy cable was inserted by hand into each thimble through full travel with no problems. Following completion of maintenance the MIDS was exercised through all thimbles with no blockage.

This same course of action is scheduled to be performed for Unit 1 during the 5th refueling outage scheduled to commence in the January / February 1984 timeframe. The only physical differences between units is that Unit 1 thimbles are 0.201" ID which is 0.009" smaller than the Unit 2 thimbles.

During the next surveillance interval, Alabama Power Company will continue ef forts to restore at least a minimum of 38 thimbles. However, if such efforts do not provide confidence that the system can be made functionally operable through the remainder of this Unit I fuel cycle ending in the January / February 1984 timeframe, Alabama Power Company may submit an additional request.

This proposed one-time change does not involve a significant hazards consideration as defined in 10CFR50.92. This change is not consistent with any of the " Examples of Amendments that are Considered Likely to Involve Significant Hazard Considerations" listed on page 14870 of the April 6, 1983 issue of the Federal Register. The proposed change does not involve a significant hazards consideration because:

1. The change does not result in an increase of the probability or consequence of an analyzed accident,

2. The change does not create the possibility of a new or different kind of accident from any accident previously evaluated, and

3. The change does not involve a reduction in a margin of safety.

Mr. S. A. Varga October 21, 1983 U. S. Nuclear Regulatory Commission Page 4 Adequate determination of the power distribution limits is provided with 37 thimbles. The added uncertainities considered in the flux map review provide additional confidence in these measurements.

The Plant Operations Review Committee has reviewed this proposed change. The Nuclear Operations Review Board will review this change at a future meeting.

The class of this proposed one-time technical specification change is designated as Class III for Unit 1 in accordance with 10CFR170.22 requirements and a check for $4,000 to cover the fee required is enclosed. NRC approval of this proposed change is requested by 5:00 p.m. CDT October 21, 1983 to support continued plant operation.

Therefore, this change is considered an " emergency" in accordance with 10CFR50.91.

In accordance with 10CFR50.30(c)(1)(i), three signed originals and forty (40) additional copies of this proposed change are enclosed. As noted by the distribution, a copy of this letter is being sent to the Alabama Power Designee in accordance with 10CFR50.91(b)(1).

If you have any questions, please advise.

Yours very truly, l

. . Clayton Jr.

FLCJ r/RLG:dd r-D9 Attachments cc: Mr. R. A. Thomas SWORN TO AND SUBSCRISED BEFORE ME Mr. G. F. Trowbridge THIS C Y DAY OF '8 S h , 1984 Mr. J. P. O'Reilly Mr. E. A. Reeves Mr. W. H. Bradford Dr. I. L. Myers JA k JALfAl v Notary Public My Commission Expires: I -l O ~h

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