ML18025B733

Forwards Request for Addl Info Re Tech Specs for Average Power Range Monitor Flow Bias Setpoints.Omb Clearance Not Required

ML18025B733
Person / Time
Site:	Browns Ferry
Issue date:	02/09/1982
From:	Vassallo D Office of Nuclear Reactor Regulation
To:	Parris H TENNESSEE VALLEY AUTHORITY
References
NUDOCS 8202260372
Download: ML18025B733 (6)

Text

DISTRIBUTION:

Docket Fi le NRC PDR L PDR Docket Nos.60-260 and 60-296 TERA NSIC IEEIEEMI DEi s enhut SNorris DClark OELD AEOD IE-3 ACRS-10 Gray File CBerlinger, CPB ORBg2 Rdg FEB S

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Hr. Hugh G. Parris Manager of Peler Tennessee Valley Authority 600A Chestnut Street, Tower II, Chattanooga, Tennessee 37401

Dear Hr. Parris:

Re:

Brogans Ferry Units 2 and 3

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8 Reference is made to your letter of Spptember 21, 1987 (TVA BFNP TS 167) requesting changes to the Brogans Ferry Technical Specifications regarding

'he APRH flow biased setpoints.

In order to complete our review, v<e need the addittional information.identified in the enclosure to tI>is letter.

Since there is no safety concern'perating with the present Technical Specifications and since <ve'recognize that you may have to obtain technical input outside TV/, the suggested response date is at your convenience.

This request for information applies only to one company (TVA) and is necessary to accommodate an action requested by TVA.

Accordingly, OIIB clearance is not required for this ~r'equest under P.L.96-611.

Sincerely, ORIGINALSIGHED SY Domenic B. Yassallo, Chief Operating Reactors Branch 02 Division. of Licensing Encl os ure:

Requ'est for Additional Information cc >v/enclosure:

See next page j'8202260372 820209

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0 Mr. Hugh G. Parris CC.

H. S.'anger, Jr., Esquire General Counsel Tennessee Valley Authority 400 Commerce Avenue E llB 33 C

Knoxville, Tennessee 37902 Mr. Ron Rogers Tennessee Valley Authority 400 Chestnut Street, Tower II Chattanooga, Tennessee 37401 Mr. H.

N. Culver 249A 'HBD

'400 Commerce Avenue Tennessee Valley Authority Knoxville, Tennessee 37902 Robert F. Sullivan U. S. Nuclear Regulatory Commission Route 2, Box 311

Athens, Alabama 35611 Athens Public Library South and Forrest

Athens, Alabama 35611 Mr. John F.

Cox Tennessee Valley Authority W9-D 207C 400 Commerce. Avenue Knoxville', Tennessee 37902 Mr. Herbert Abercrombie Tennessee Valley Authority P. 0. Box'000

Decatur, Alabama 35602 James P. O'Rei lly Regional Administrator, Region II U.S. Nuclear Regulatory Commission 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303

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Enclosure REQUEST FOR ADDITIONAL INFORtRTION FLOW BIASED SCRAH AND ROD BLOCK LIMITS BROWNS FERRY UNIT NOS.

2 AND 3

'OCKET NOS. 50-260 AND 50-296 In your application of September 21, 1981 (TYA BFNP TS 167), you proposed changes.,to the Browns Ferry Units 2 and 3 Technical Specifications regarding the equations involving the fraction of rated thermal power (FRP) to core maximum fraction of limiting power density (CtlFLPD).

One of the proposed changes is to move these equations without changes from Section 2.1 (Fuel Cladding Integrity-Limiting Safety System Settings) to Section 3.5 of the Technical Specifications as a Limiting Condition for Operation.

This is con-sistent with the BWR Standard Technical Specifications and is acceptable.

We note, however, that you propose to delete the bases for these equations from Sections 1.1 and 4.1 and that these bases are not proposed to be included elsewhere.

You have also proposed to modify the required corrective action when the Ct<FLPD exceeds unity.

At present, you are required to initiate action within 15 minutes to restore operation within prescribed limits and to restore the plant within limits within two hours or reduce thermal power to less than 25K.

This is the same requirement as in the BWR Standard Technical Specifi-cations.

You have proposed that six hours'e allowed to restore the plant within limits.

Since these limits primarily come into play during startup, the normal movement of control rods should restore'he plant within limits within six hours without any other specific, action. being taken.

We generally agree with the proposed change in the Technical Specifications but need additional supporting and background information to prepare an adequate written Safety Evaluation.

You point out that under the old minimum critical heat flux ratio correlations, the peaking factor adjustment to the flaw biased scram and rod block equations had relevance to maintaining core limits in certain flow excursion transients, As we understand it, the peaking factor was put in because of a localized phenomenon in the Hench-Levy heat transfer correlation.

Now that the correlations are based on bundle power effects, the peaking factor adjustment has lost some of its safety significance, because power in a single rod is no longer critical.

In any of the Safety Evaluations we prepare supporting an.amendment, we have to conclude. that there is not a significant hazards consideration based on the th h

i t ~life td i

fty gi.

A, indicated above, we are fairly certain this is the case or else we would have prenoticed your application.

But to reach this determination, we need:

1.

A discussion of the differences between the two departure-from-nuclear-boiling heat transfer correlations-Hench-Levy and GETAB-GEXL.

2.

Identification of pertinent thermal limits and a discussion of why the change in thermal limits justifies a longer time to take corrective

'ction (or possibly justification why the limits can be removed from the Technical Specifications).

, 3.

A discussion of why the system is adequately protected by the 120K fixed scram in the absence of any peaking factor adjustment and that the calibration techniques used in setting the ApfUP scram trip settings (under high APRM Gain Adjustment Factor} insure that the 120K setpoint is not exceeded.

4.

The bases for these limits in the Technical Specifications, ifyou propose to retain the equations as a limiting condition for operation (as in your submittal).

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