ML20059K184

Safety Evaluation Supporting Amends 83 & 76 to Licenses NPF-2 & NPF-8,respectively

ML20059K184
Person / Time
Site:	Farley
Issue date:	09/07/1990
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20059K180	List: ML20059K174 ML20059K184
References
NUDOCS 9009210205
Download: ML20059K184 (4)

Text

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k-UNITED STATES

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NUCLEAR REGULATORY COMMISSION l

o WASHINGTON. D. C. 20005 -

SAFETY. EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION-SUPPORTING AMENDMENT NO. 83-TO FACILITY OPERATING LICENSE NO. NPF-2 AND AMENDMENT NO. 76 TO FACILITY OPERATING LICENSE NO.- NPF-8 ALABAMA POWER COMPANY JOSEPH M. FARLEY: NUCLEAR PLANT. Uh "S 1 AND 2 D0_CKET NOS. 50-348 AND 50-364;

1.0 INTRODUCTION

By'1etter. dated June 12, 1990, AlabamaPowerCompany(the-licensee) submitted a request for changes to the Technical Specifications of the.

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Joseph M. Farley Nuclear Plant, Units 1 and 2 (Farley). The amendments redefine the fully withdrawn position of'al_1 rod cluster control-assembly-(RC(,A) banks to minimize localized :RCCA wear.

Currently, the fully withdrawn position for theicontrol and' shutdown RCCA banks is defined as 228 steps above rod bottom. - The~ proposed changes will allow the control' and shutdown RCCA banks' to be designated as fully withdrawn between: steps 225'and'231, inclusive..These changes are consister.t with Westinghouse's

- recommendation to axially reposition the RCCAs up'to three steps to 1 distribute wear to other locations.on the.RCCA rodlets in. order,to extend rod'11fe.

The RCCAs in Westinghouse pressurized water reactors were originallyi estimated to last for at least 15-years before the absorber-cladding, a thin tube, would show excessive thinning as a result of sliding wear.' In 1983, after 13 years of operation,.the RCCAs were inspected at Point Beach:

Nuclear Plant, Unit 2.,LThe result of this' inspection showed that slidingL l wear was minor, but severe fretting wear had occurred on-several tubes.

LSubsequent inspections at'the Kewaunee and Haddam Neck plants',_which:had been in operation for more than '12 ' years, also showed fretting-wearEThe-marks of fretting wear, were aboutE1 inch inL length and were found adjacent to the guide blocks that position the' rods when the RCCAs are in their withdrawn position.

The fretting resulted from flow-induced vib'ratory contact between the rods and the' guide blocks during long. periods of steady-state power operation.

Vibration.is hydraulically induced by, flow of the reactor coolant; therefore, Lit is a continuous, process when the reactor coolant pumps are in operation.

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.2.0 EVALUATION:

Currently, the fully withdrawn position for all of the Farley RCCAs is 228' steps above rod bottom with a tip-to-tip distance of 128 steps maintained between the: control banks during overlap. operation. To avoid the fretti.x wear at the same locationi Westinghouse has recommended that the fully.

withdrawn parked posision beEchanged periodically.. ;In this way the wear will be spread over a greater-surface area of-the,rodlet cladding.

c Thelicenseeproposeddefining"fullywithdrawn"tomeanbetween225and-231 steps, inclusive, above reactor bottom ~ for all RCCA banks. Between 228 and 231 steps, the RCCAs are withdrawn at least two steps above the active:

1 fuel. Thus with; respect to core Also at 231 steps the RCCAs will physics, the effects are equivalent.-

remainLinserted in:the guide thimbles of

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the. fuel assemblies and:thus will. allow,for a smooth rod drop.

The rod drop time assumed in the safety analysis will still be bounding. When the

- RCCAs are withdrawn to 225 steps, they will actually be inserted one step; 1

(0.63 inches) into the active fuel.

Thus the key physics safety para-meters were evaluated to determine if the change invalidated any safety l

analysis assumptions.

The effect on the calcu ation performed to verify i

shutdown margin is minimal, 'a: decrease of 0.03% delta-rho (change in reactivity). This effect can be accommodated by the available excess-L-

margin at end-of-life which is approximately 1.40% delta-rho. Other 1

physics parameters such as core axial. power distributions,Mifferential 1

and integral rod worth:are affacted only slightly.- Sufficient margin exists in the safety (F-)its expected to increase by less than 1% in the analysis to: account for these' changes. The heat flux 1

hot. channel factor bottomofthe.~coreanhthe-axial'offsetwillbemorenegativebyelessthan 1%.--There is sufficient margin to' bound these effects.

As part of-the. reload safety evaluation processP the l fully withdrawn RCCA -

position which is selected for.use throughout each cycle will be' j

evaluated.-

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SUMMARY

j The staff has reviewed and evalauated the licensee's request. Because the-proposed change will remove. or insert the RCCAs only sli: tly "to or out.

~ of the active fuel region,'the staff expects negligible erfects rrom the y

proposed change as reported;1n the licensee's-evaluation. Base.,on the=

L above considerations, we find:the proposed Technical Specification changes D

acceptable, i

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4.0 ' ENVIRONMENTAL CONSIDERATION _

j These' amendments change a: requirement with respect toJinsta11ation orb use of a facility component located within the restricted areas as defined,.

in.10 CFR Parts 20 and: changes the surveillance _ requirements. The staff; 1

'has determined that these amendments involve no significant increase in.

1 the amounts,, and no significant' change -int the. types, of:any offluents: that may be released off site, and that there is no significant;The' Commission increase'in individual or cumulative occupational radiation exposure..

has previously issued a proposed finding that these 6mndments involve no; significant hazards consideration, and there has~been a public comment on 2

.t such finding.' Accordingly, these amendments meet the-eli for-categoric,al exclusion set forth in 10 CFR 51.22(c)(9)gibility criteria-

. - Pursuant toL10; CFR.51.22(b), no. environmental' impact statement or environmental.

assessment need be prepared in connection with the ' issuance of _these, amendments..

5.0 CONCLUSION

The Commission made a' proposed-determination that this amendment involves,,

no significant: hazards' consideration which was published in the Federal ~

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' Register (55 FR 28472) on' July 11; 1990, and consulted with the state

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.of Alabama. No public comments-or

? quests for hearing were received, and:

the State of Ala)ama did not have ey comments. '

!Thestaffhasconcluded,basedontheconsiderationsdiicussedabove, W

'I that:. (1)1there Lis reasonable assurance that the. health and; safety of the?

ublic will not be' endangered by. operation in the: proposed manner,-

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p(2) such activities will be-conducted in compliance with the-Commission's:

a regulations; and _(3) the issuance of these amendments will'not be inimical' to; the common ' defense' and security or_'to; the health and safety. of thecpublic.

,y Principal Contributor:

i. Chatterton H

.y Dated:' September _.7, 1990-5

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. AMENDMENT NO.

AMENDMENT NO. 83 TO FACILITY OPERATING LICENSE NO. NPR FARLEY, UNIT 1-4" 76 TO FACILITY OPERATING LICENSE NO. NPF FARLEY, UKIT 2-

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