ML20112B404

Application for Amend to Licenses DPR-53 & DPR-69,revising Tech Specs Re Flux Peaking Augmentation Factor & Control Element Assembly Power Dependent Insertion Limits.Fee Paid

ML20112B404
Person / Time
Site:	Calvert Cliffs
Issue date:	12/31/1984
From:	Lundvall A BALTIMORE GAS & ELECTRIC CO.
To:	John Miller Office of Nuclear Reactor Regulation
Shared Package
ML20112B406	List: ML20112B404 ML20112B421 ML20112B446
References
NUDOCS 8501100376
Download: ML20112B404 (4)

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1 BALTI MORE GAS AND ELECTRIC CHARLES CENTER.P.O. BOX 1475 BALTIMORE, MARYLAND 21203 ARTHUR E. LUNDVALL. JR.

vice Persocra suppov December 31,1984 U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, D.C. 20555 ATTENTION: Mr. J. R. Miller, Chief Operating Reactors Branch #3

SUBJECT:

Calvert Cliffs Nuclear Power Plant Unit Nos.1 & 2, Docket Nos. 50-317 & 50-318 Request for Amendment ATTACHMENTS: (1) Technical Specification Figure 4.2-1, page 3/4.2-5 (being deleted for Units 1 and 2)

(2) Marked up Technical Specification pages 3/4.2-2 and B3/4.2-1 (Units 1 and 2)

(3) Marked up Technical Specification Figure 3.1-2, page 3/4.1-27 indicating change (Unit 1 only)

(4) Clad Collapse / Augmentation Factor Analysis for Calvert Cliffs (5) EPRI Report, " Evaluation of Interpellet-Gap Formation and Clad Collapse in Modern PWR Fuel Rods", EPRI Contract RP 2061-6 Task A2, prepared by Combustion Engineering, Final Report, August 1984 (not yet released)

Gentlemen:

The Baltimore Gas and Electric Company hereby requests an amendment to its Operating License No. DPR-53 and DPR-69 for Calvert Cliffs Unit Nos.1 & 2, respectively, with the submittal of the enclosed changes to the Technical Specifications.

PROPOSED CHANGES (BG&E FCR 84-3003)

1. Changes to delete the flux peaking augmentation factor:

Delete existing page 3/4.2-5. Remove existing pages 3/4.2-2 and B3/4.2-1 and replace with attached marked-up pages. These changes apply to Units 1 and 2.

2. Changes to CEA Power Dependent Insertion Limits:

Remove existing page 3/4.1-27 and replace with attached marked-up page. This k change applies to Unit 1 only. g 8501100376 841231 gWJ /50 00 T PDR ADOCK 05000317 P PDR h

Mr. J. R. Mill;r December 31,1984 Page 2 f

DBCUMION

1. CHANGES TO DELETE THE FLUX PEAKING AUGMENTATION FACTOR

[ One of the factors involved in setpoint limits for the Incore Detector Monitoring i

System is the flux peaking augmentation factor (see Attachment 1). That factor 3 'is based on a model for the formation and distribution of axial gaps in the fuel 4-pellet stack esused by pellet densification and lockup with the clad. Decreased neutron absorption in the location of the gap leads to power peaking in adjacent

areas. Complete clad collapse into the gap region, replacing the fuel / gap area with moderator, enhances that effect. The augmentation factor is defined as the ratio of peak augmented power (due to axial gaps) to peak unaugmented power.

Since the model for the distribution of axial gaps predicts increasing gap size as a

function of core height, the end result is a set of axially increasing peaking g augmentation factors, with a maximum value at the top of the core.

, ~ The fuel upon which this model is based differs significantly from modern fuelin many important aspects. Whereas old fuel was prone to densification and was not prepressurized, modern fuel is resistant to densification, and is prepressurized.

! The resistance of modern fuel to densification eliminates the propensity for interpellet gap formation, and prepressurization inhibits clad creepdown, diminishing - the pellet-clad lockup which enhanced gap formation. Data supporting elimination of the axial gap induced augmentation factor are presented in Attachments 4 and 5. An upper limit of .022 inches axial gap, as compared to 0.7 inches maximum gap size for older fuel (upon which the present model is baswl) yields an augmentation factor which is insignificant compared to the' uncertainties involved in developing setpoints for the Incore Detector Monitoring System.

Based on this, the augmentation factor should be removed,' deleting Technical Specification Figure 4.2-1 (Attachment 1), and changing Technical Specification page 3/4.2-2 and Bases page B 3/4.2-1, as shown in Attachment 2.

2. CHANGES TO CEA POWER DEPENDENT INSERTION LIMITS The current and proposed Power Dependent Insertion Limits are as shown on Attachment 3. The new limits are more conservative, in that they require Group

. 3 to be more fully withdrawn (40% insertion versus 60% insertion). The result of.

this change will be an increased flexibility to accommodate future design changes without reducing shutdown margin.

' DETERMINATION OF SIGNIFICANT HAZARDS

,1. CHANGES TO DELETE THE FLUX PEAKING AUGMENTATION FACTOR The pivpcxd changes are consistent with example vi of amendments considered not likely to involve significant hazards considerations as shown in Federal Register Notlee 1487 dated April 6,1983, since they involve a small reduction in peak linear heat rate penalty resulting from the application of a small refinement of a previously used calculational model or design method.

Mr. J.' R. Mill;r December 31,1984

- Page 3 o There is a small reduction in the margin of safety as a result of the proposed changes.

By eliminating the augmentation factor, the core will be allowed to operate at a slightly higher linear heat rate, slightly closer to the Specified Acceptable Fuel Design Limits. This does not lead to a significant hazard, as there is no -need for an augmentation factor since nondensifying prepressurized fuel does not exhibit axial gap formation as did fuel upon which the augmentation factor was based. The elimination of this factor does not significantly reduce the margin of safety as it merely reflects refinements to the fuel performance model based on present fuel designs.

o The changes will not result in any increase in the probability or consequences of any accident previously evaluated.

The change incorporates a model refinement reflecting present' fuel designs and does not adversely affect accident consequences or initiating events.

o The changes will not create the possibility of a new or different kind of accident from any accident previously evaluated.

No new accident initiators are created by the incorporation of the model refinements. These refinements merely reflect present fuel designs.

2) CHANGES TO CEA POWER DEPENDENT INSERTION e

The proposed changes are consistent with example 11 of amendments considered not likely to involve significant hazards considerations as shown in Federal Register Notice 1487 dated April 6,1983, since they pose an additional limitation, restriction, or control not presently included in the Technical Specifications. Thereforer o There is no reduction in the margin of safety as a result of the proposed changes.

o The changes will not result in any increase in the probability or consequences of any accident previously evaluated.

o The changes will not create the possibility of a new or different kind of-accident from 'any accident previously evaluated.

SAFETY COMMFrrEE REVIEW

., These proposed changes to the Technical Specifications and the determination of significant hazards have been reviewed by our Plant Operations and Off-Site Safety Review Committees, and they have concluded that implementation of these changes will not result in an undue risk to the health and safety of the public.

Mr. J. R.' Mill:r December 31,1984 Page 4 FEE DETERMINATION Pursuant to 10 CFR 170.21, we ete including BG&E check number A314880 in the amount of $150.00 to cover the application fee for this request.

Very truly yours, f , r}&

h STATE OF MARYLAND :

TO WIT:

CrrY OF BAI.TIMORE :

Arthur E. Lundvall, Jr., being duly sworn states that he is Vice President of the s

Baltimore Gas and Electric Company, a corpt.'ation of the State of Maryland; that he provides the foregoing response for the purposes therein set forth; that the statements made are true and correct to the best of his knowledge, information, and belief; and that he was authorized to provide the response on behalf of said Corporation.

WirNESS my Hand and Notarial Seal: [121._ r L ~_ s Notary Public My Commission Expires: 7f.ftt.

I I AEL/ PAP /jes cc: D.A. Brune, Esq.

G.F. Trowbridge, Esq.

D.H. Jaffe, NRC T. Foley, NRC T. Magette, DNR

, - _. .